JP2003342792A - Method of forming flat anion electrodeposition paint film and painted material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a flat anion electrodeposition paint which has excellent finishing properties, die mark hiding power, paint film performance and low temperature curing properties. <P>SOLUTION: The method of forming a flat anion electrodeposition paint film comprises: a step 1 where an anion electrodeposition paint (I) containing a vinyl polymer resin (A) and a cross-linking agent (B) in which the difference in solubility parameters between the vinyl polymer resin (A) and the cross- linking agent (B) is 0.5 to 1.5 and composed so as to be dispersed in water is applied to an aluminum alloy by electrodeposition coating; a step 2 where the uncured paint film formed in the step 1 is immersed into an aqueous solution (II) of pH 7.1 to 14 obtained by adding a basic compound of one or more equivalences to at least one kind of higher alkylaryl sulfonate, and is supplied with currents; a step 3 where the paint film is washed with pure water or industrial water or a recovered liquid; and a step 4 where the paint film is baked and dried. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for forming a matte anion electrodeposition coating film which is excellent in finish properties, dice mark concealing properties and coating film performance.

[0002]

2. Description of the Related Art Conventionally, since aluminum has better workability at high temperatures than many metals (such as steel), it is relatively easy to obtain a die material having various cross-sectional shapes by hot extrusion. Aluminum alloys are manufactured by mixing various metals with such aluminum.

Such an aluminum alloy 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. ing.

The hot extrusion method of the aluminum alloy is usually carried out by heating a cylindrical aluminum ingot to melt it, then putting this melt in an extruder and pressing it into a die having a hole of a predetermined cross-sectional shape. The method is to obtain a mold material having a predetermined shape by passing through the holes in a flexible manner.

The aluminum alloy itself is not easily corroded by corrosive substances such as salt water resistance, but easily corrodes by alkali resistance (mortar, etc.). It is general that the matte clear coating film is coated with a matte anion electrodeposition paint or the like.

As a conventional invention, a basic anion electrodeposition coating composition is applied, washed with water, and then uncured, and a basic compound containing at least one higher alkylaryl sulfonic acid is added to pH 1 to Energize in the aqueous solution of 7,
Next, there is a matte electrodeposition coating method (see Japanese Patent Laid-Open No. 229494/1984) in which the material is washed with water and then baked and cured.

However, according to this electrodeposition coating method, pH 1 to
The aqueous solution of higher alkylaryl sulfonic acid of 7 has a matte coating film, but the catalytic effect proceeds only on the surface of the coating film, resulting in uneven coating to deteriorate coating performance, insufficient low temperature curability, and designability. Therefore, there was a problem that a satisfactory value was not obtained in the L value, which is a measure of the degree of matting.

In the above invention, when the pH exceeds 7, the matting effect becomes weak, but since the basic anion electrodeposition coating film is a basic solution, there is little shock due to immersion, and the aqueous solution is inside the gas holes generated by electrodeposition. As a result, the finishability, coating film performance and low temperature curability were good.

In the anion electrodeposition coating line, two electrodeposition tanks are used as shown in FIG. 1, and a glossy anion electrodeposition paint or a matte anion electrodeposition paint is applied to an object to be coated according to the purpose. In many cases, examples of the invention relating to such a matte anion electrodeposition coating composition include, for example, a matte anion type electrodeposition coating composition obtained by adjusting a solubility parameter of a resin and then dispersing the mixture in water to obtain an emulsion. 2001-
There are inventions such as Japanese Patent Laid-Open No. 131494).

However, the matte anionic electrodeposition coating composition has a fixed design composition because the composition of the coating composition is fixed, and it is not easy to change the matting degree. From this, finish, dice mark concealment, coating performance,
There has been a demand for a matte anion type electrodeposition coating film forming method which has excellent low-temperature curability and can easily change the design.

[0011]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have found that the difference between the solubility parameters of resins is 0.5 to 1.5. The coating obtained by electrodeposition coating of the coating composition is uncured, and at least one higher alkylaryl sulfonic acid is added with 1 equivalent or more of a basic compound to adjust the pH to 7.
The present invention has been completed by a method for forming a coating film by immersing in an aqueous solution adjusted to 1 to 14, applying electricity, washing with water, baking and drying.

That is, the present invention is as follows: Method for forming matte anionic electrodeposition coating film according to the following steps 1 to 4, step 1: vinyl having a difference in solubility parameter between the vinyl polymer resin (A) and the crosslinking agent (B) of 0.5 to 1.5 Step of applying an anionic electrodeposition coating (I) containing a polymer resin (A) and a cross-linking agent (B) and dispersed in water to an aluminum alloy by electrodeposition coating, Step 2: uncured coating film obtained in Step 1 Is immersed in an aqueous solution (II) having a pH of 7.1 to 14 in which at least one higher alkylaryl sulfonic acid is added in an amount of 1 equivalent or more of a basic compound to conduct electricity, Step 3: Pure water, Alternatively, a step of washing with industrial water or a recovered liquid, Step 4: a step of baking and drying. 2. The energization condition in the aqueous solution (II) is 10 as the first step.
After applying a voltage of ~ 150V, the second step is 150
The method for forming a matte anion electrodeposition coating film according to item 1, which is a two-step energization method in which a voltage of ˜300 V is applied. 3. The vinyl copolymer resin (A) is a hydroxyl group-containing unsaturated monomer (a), a carboxyl group-containing unsaturated monomer (b), and another radically polymerizable unsaturated monomer (c).
3. The method for forming a matte anionic electrodeposition coating film according to item 1 or 2, which is obtained by radical copolymerizing 4. The matte anionic type electrodeposition coating composition according to any one of 1 to 3, wherein the crosslinking agent (B) is an amino resin curing agent and / or a blocked isocyanate compound. 5. The matte anion electrodeposition coating film forming method according to any one of items 1 to 4, wherein the higher alkylaryl sulfonic acids are dinonylnaphthalene sulfonic acid and / or dinonyl naphthalene disulfonic acid. The L value of the matte coating film obtained by the method for forming an anion electrodeposition coating film according to any one of 1 to 5 is 10
Coated objects in the range of .about.25.

[0013]

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

Anion electrodeposition coating resins Examples of resins for anion electrodeposition coating materials include vinyl copolymer resins, polyester resins, fluororesins, rubber resins and modified resins thereof, but from the viewpoint of weather resistance. Vinyl copolymer resins are preferred. A hydroxyl group-containing unsaturated monomer (a), a carboxyl group-containing unsaturated monomer (b),
It is a water-dispersible vinyl copolymer resin (A) obtained by radically copolymerizing another unsaturated monomer (c).

The unsaturated monomer containing a hydroxyl group (a) is, for example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, (poly) ethylene glycol monomer. (Meth) acrylate, (poly) propylene glycol
Rumono (meth) acrylate, hydroxybutyl vinyl ether, (meth) allyl alcohol, and the above-mentioned unsaturated monomers containing a hydroxyl group and β-propiolactone, dimethylpropiolactone, butyrolactone, γ-valerolactone. , Γ-caprolactone, γ-caprylolactone, γ-laurolactone, ε-caprolactone, δ-
Trade names such as reaction products with lactone compounds such as caprolactone are Praxel FM1 (manufactured by Daicel Chemical Industries,
Trade names, caprolactone-modified (meth) acrylic acid hydroxyesters, Praxel FM2 (same left), Praxel FM3 (same left), Praxel FA1 (same left), Praxel FA2 (same left), Praxel FA3 (same left), etc.

Unsaturated monomer containing carboxyl group (b)
Are, for example, (meth) acrylic acid, maleic acid, Praxel FM1A (hereinafter, manufactured by Daicel Chemical Co., Ltd., a caprolactone-modified carboxyl group-containing (meth) acrylic monomer,
(Product name), Praxel FM4A, Praxel FM10A
Etc.

The other unsaturated monomers (c) are, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth).
(Meth) such as butyl acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate
C ₁ -C ₁₈ alkyl or cycloalkyl esters of acrylic acid, aromatic vinyl monomers such as styrene,
(Meth) acrylic acid amide, N-butoxymethyl (meth) acrylamide, (meth) acrylamide such as N-methylol (meth) acrylamide and derivatives thereof, (meth) acrylonitrile compounds and the like.

In addition, for example, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monoacrylate,
Polypropylene glycol monomethacrylate, polyethylene glycol monomethyl ether monoacrylate
And polyethylene-modified acrylic unsaturated monomers such as polyethylene glycol monomethyl ether monomethacrylate.

The mixing ratio of these monomers is such that the hydroxyl group-containing unsaturated monomer (a), the carboxyl group-containing unsaturated monomer (b), and the other unsaturated monomer (c) are contained in the total amount of the solid content of the hydroxyl group-containing unsaturated monomer (c). 3-5 unsaturated monomers
0% by weight, preferably 5 to 40% by weight, the carboxyl group-containing unsaturated monomer is 2 to 40% by weight, preferably 4 to
30% by weight, other unsaturated monomers-10 to 90% by weight, preferably 20 to 70% by weight.

The method for producing the vinyl copolymer resin (A) is as follows:
It can be carried out by a conventionally known production method, for example, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method or the like, but the following solution polymerization method is preferable.

Examples of the organic solvent used for radical copolymerization include alcohols such as n-propanol, isopropanol, n-butanol, t-butyl alcohol and isobutyl alcohol, cellosolve, methyl cellosolve, butyl cellosolve, methyl carbitol, Two
-Methoxyethanol, 2-ethoxyethanol, 2-
Isopropoxy ethanol, 2-butoxy ethanol,
Diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, 1-
Ethers such as methoxy-2-propanol, 1-ethoxy-2-propanol and dipropylene glycol monomethyl ether can be preferably used.

In addition to these, if necessary, for example, aromatics such as xylene and toluene, acetone, methyl ethyl ketone, 2-pentanone, 2-hexanone,
Ketones such as methyl isobutyl ketone, isophorone and cyclohexanone, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, 3-
Esters such as methoxybutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl propionate and ethyl propionate can also be used in combination.

The radical polymerizable initiator used for radical copolymerization is, for example, benzoyl peroxide or di-t.
-Butyl hydroperoxide, t-butyl hydroperoxide, cumyl peroxide, cumene hydroperoxide, diisopropylbenzane hydroperoxide, t-butylperoxybenzoate, lauryl peroxide, acetyl peroxide, t-
Examples thereof include peroxides such as butylperoxy-2-ethylhexanoate, and azo compounds such as α, α′-azobisisobutylnitrile, azobisdimethylvaleronitrile and azobiscyclohexanecarbonitrile.

The solution polymerization reaction is carried out in the above-mentioned organic solvent by using monomers such as a hydroxyl group-containing unsaturated monomer (a), a carboxyl group-containing unsaturated monomer (b) and other unsaturated monomers (c), radical polymerization The mixture of initiators is, for example, about 50 to 200 ° C, preferably about 60 to 180 ° C.
It can be obtained by reacting at the temperature of about 1 to 24 hours, preferably about 2 to 10 hours.

The hydroxyl value of the vinyl polymer resin thus obtained is in the range of 30 to 200 mgKOH / g, preferably 5
0 ~ 180mgKOH / g, acid value 15 ~ 150mgK
OH / g range, preferably 20-130 mg KOH /
g, the number average molecular weight is preferably 10,000 to 100,000, and more preferably 20,000 to 60,000.

If the number average molecular weight is less than 10,000, the coating performance is insufficient, and the number average molecular weight is 100,
If it exceeds 000, the aqueous resin may have a high viscosity and it may be difficult to form a uniform emulsion when dispersed in water.

Crosslinking agent (B): The amino resin used as the crosslinking agent (B) may be a conventionally known amino resin. Amino resins include melamine, urea,
Examples thereof include a methylolated amino resin obtained by reacting an amino component such as benzoguanamine, acetogranamine, sterogtanamine, spiroguanamine, and dicyandiamide with an aldehyde. Examples of the aldehyde include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like.

Further, a product obtained by etherifying this methylolated amino resin with an appropriate alcohol can be used.
Examples of alcohols used for etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol,
Examples thereof include i-butyl alcohol, 2-ethylbutanol, 2-ethylhexanol and the like.

The blocked polyisocyanate compound used as the crosslinking agent (B) may be a conventionally known polyisocyanate compound obtained by blocking the isocyanate group with a blocking agent.

Examples of the polyisocyanate compound include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; cyclic aliphatic diisocyanates such as hydrogenated xylylene diisocyanate and isophorone diisocyanate.

Tolylene diisocyanate or 4,
Organic diisocyanates such as aromatic diisocyanates such as 4'-diphenylmethane diisocyanate itself, or adducts of each of these organic diisocyanates with polyhydric alcohols, low molecular weight polyester resins, water, etc. Examples thereof include cyclized polymers, and isocyanate / biuret compounds. Typical examples of commercially available products thereof include "Bernock D-750, -800, DN-950,
-970 or 15-455 "[above, Dainippon Ink and Chemicals, product]," death module L, N, HL, I
L or N3390 "[Product of Bayer GmbH, West Germany]," Takenate D-102, -202, -110N
Or 123N "[Takeda Yakuhin / Products]," Coronate L, HL, EH or 203 "[Japan Polyurethane Industry / Products] or" Duranate 24A-90C "
X "[Asahi Kasei Kogyo / Product] etc.) and the like.
Among these, aliphatic diisocyanates and cycloaliphatic diisocyanates are preferable.

Examples of the blocking agent include phenol-based, lactam-based, active methylene-based, alcohol-based, mercaptan-based, acid amide-based, imide-based, amine-based, imidazole-based, urea-based and carbamate esters. A blocking agent such as a system-based, imine-based, or sulfite-based blocking agent is used.

In the present invention, the mixing ratio of the vinyl copolymer resin (A) and the crosslinking agent (B) is 30 to 90% by weight of the vinyl copolymer resin (A) and 70 to 1 of the crosslinking agent (B).
0% by weight, preferably 35% vinyl copolymer resin (A)
˜80 wt%, and the cross-linking agent (B) is 65-20 wt%. When the amount of the cross-linking agent (B) is less than 10% by weight, the coating properties such as weather resistance, scratch resistance and coating processability are deteriorated, and when it exceeds 70% by weight, the coating properties such as weather resistance and coating processability are deteriorated. Becomes worse.

Since the difference in solubility parameter between the vinyl copolymer resin (A) and the cross-linking agent (B) is 0.5 to 1.5, a basic compound is added to the higher alkylaryl sulfonic acid. It was found that a matte coating film excellent in finishability, dice mark concealing property, coating film performance, and low temperature curability can be obtained by immersing in the following aqueous solution (II), energizing, washing with water, and baking and drying. The solubility parameter represents a measure of intermolecular interaction of liquid molecules and is represented by the following formula.

The SP value of a resin can be measured by a turbidity titration, and specifically, the K. W. SUH,
J. M. CORBETT formula (Journalof A
pplied Polymer Science, 12,
2359, 1968).

[0036]

[Equation 1] (In the formula, V _H is the volume fraction of n-hexane, V _D is the volume fraction of deionized water, δ _H is the SP value of n-hexane, and δ _D is the SP value of deionized water.) Then, 0.5 g of dried vinyl resin (solid content) was dissolved in 10 ml of acetone, n-hexane was gradually added, the titration amount H (ml) at the turbid point was read, and similarly deionized in the acetone solution. Read the titer D (ml) at the turbidity point with the addition of water and apply these to the formula below to calculate V _H , V _D , δ _H , δ _D.

The SP value of each solvent is acetone: 9.7.
5, n-hexane: 7.24, deionized water: 23.43
Is. V _H = H / (10 + H) V _D = D / (10 + D), δ
_{H 2} = 9.75 × 10 / (10 + H) + 7.24 × H /
(10 + H), δ _D = 9.75 × 10 / (10 + D)
+ 23.43 × D / (10 + D), and the SP value can be easily adjusted by the composition and ratio of the monomers.

The basic compound used for neutralizing the vinyl copolymer resin (A) is ethylamine, propylamine, butylamine, benzylamine, monoethanolamine, neopentanolamine, 2-aminopropanol, 3-aminoamine.
Primary monoamines such as aminopropanol; diethylamidiethanolamine, di-n- or di-iso-propanolamine, N-methylethanolamine, N-
Secondary monoamines such as ethylethanolamine; dimethylethanolamine, trimethylamine, triethylamine, triisopropylamine, methyldiethanolamine, tertiary monoamines such as dimethylaminoethanol; diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine Such as polyamine triethylamine.

The compounding ratio of the basic compound in the anionic electrodeposition coating composition (I) is preferably in the range of 0.1 to 1.0 equivalents, and is equivalent to that of the vinyl copolymer resin (A) and the crosslinking agent (B). Basic compound is 0.
01 to 10% by weight, preferably 0.05 to 5% by weight
Is. If the amount of the basic compound is less than 0.01% by weight, the water dispersibility of the aqueous emulsion will be poor, and if it exceeds 10% by weight, the hydrophilicity will increase and the coating performance will deteriorate.

An ultraviolet absorber and a light stabilizer can be added to the anionic electrodeposition coating composition (I).

As the ultraviolet absorber, salicylic acid derivatives such as phenyl salicylate, p-octylphenyl salicylate and 4-t-butylphenyl salicylate;
2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4
-Methoxy-2'-carboxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-octoxybenzophenone , 2-hydroxy-4-octadecyloxybenzophenone, sodium 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfobenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 4-dodecyloxy- 2-hydroxybenzophenone, 5-chloro-2-hydroxybenzophenone, resorcinol monobenzoate, 2,4-dibenzoylresorcinol, 4,6-dibenzoylresorcinol,
Benzophenone compounds such as hydroxydodecylbenzophenone and 2,2'-dihydroxy-4 (3-methacryloxy-2-hydroxypropoxy) benzophenone; 2
Examples thereof include benzotriazole-based compounds such as-(2'-hydroxy-5'-methylphenyl) benzotriazole and other compounds (anilide oxalic acid, cyanoacrylate, etc.).

The light stabilizer used in the mixed system is a hindered amine derivative, specifically, bis- (2,2
′, 6,6′-Tetramethyl-4-piperidinyl) sebacate, 4-benzoyloxy-2,2 ′, 6,6′-
Tetramethylpiperidine and the like can be mentioned, and one or more of these can be appropriately selected and used.

The anion electrodeposition coating composition (I) is prepared by adding a vinyl copolymer resin (A), a cross-linking agent (B), a basic compound and deionized water, and stirring the mixture with a desperer or the like.

The anionic electrodeposition coating composition (I) is added with a pigment, a dye, a curing catalyst and a flow control agent, if necessary, to adjust the pH.
Adjust and add deionized water to a solid content of 5% by weight to 20
A weight% of anionic electrodeposition paint (I) can be obtained.
As an object to be coated with the anionic electrodeposition coating material (I), it is preferable to apply an electrodeposition coating to a colored or uncolored anodized aluminum material.

To form a coating film using the anionic electrodeposition coating composition, the anion electrodeposition coating composition obtained above is used as a bath (in a bath) and the bath temperature is 10 to 30 ° C., preferably 15 ~
After the treated aluminum alloy is immersed in a bath at 25 ° C., anion electrodeposition coating is performed so that the dry film thickness is about 5 to 30 μm.

About the aqueous solution (II), the coating film obtained by anion electrodeposition coating is washed with water and then, while still uncured, at least one higher alkylaryl sulfonic acid is added with 1 equivalent or more of a basic compound to adjust the pH to 7 Immersed in an aqueous solution (II) of 1 to 14 and a voltage of 50 to 35
After energizing at 0V for 10 to 240 seconds, wash with water and 140
A matte coating film is obtained by baking and drying at ~ 200 ° C for 10 to 120 minutes.

Examples of such higher alkylaryl sulfonic acids include compounds represented by the following general formulas (1) to (5).

[0048]

Embedded image General formula (1) (R is _an alkyl group of C 3 _{-C 18)}

[0049]

Embedded image General formula (2) (R ₁ and R ₂ are C _{3 to} C ₁₈ alkyl groups)

[0050]

Embedded image General formula (3) (R is _an alkyl group of C 3 _{-C 12)}

[0051]

Embedded image General formula (4) (R ₁ and R ₂ are C _{3 to} C ₁₂ alkyl groups)

[0052]

Embedded image General formula (5) (R ₁ and R ₂ are C _{3 to} C ₁₂ Alkyl Group) Specific examples of the higher alkylaryl sulfonic acids include:
n-butylbenzenesulfonic acid, n-aminobenzenesulfonic acid, n-octylsulfonic acid, n-octylbenzenesulfonic acid, n-dodecylbenzenesulfonic acid, n
-Octadecylbenzenesulfonic acid, n-dibutylbenzenesulfonic acid, isopropylnaphthalenesulfonic acid,
Dodecyl naphthalene sulfonic acid, dinonyl naphthalene sulfonic acid, dinonyl naphthalene disulfonic acid, etc. are mentioned. The concentration of higher alkylaryl sulfonic acids is in the range of 0.1 to 20% by weight, preferably 0.3 to
10% by weight, and more preferably 0.5 to 8% by weight.

Of these, dinonylnaphthalene sulfonic acid and dinonyl naphthalene disulfonic acid are preferred. These higher alkylaryl sulfonic acids are basic compounds such as ethylamine, propylamine, butylamine, benzylamine, monoethanolamine,
Neopentanolamine, 2-aminopropanol, 3
-Primary monoamines such as aminopropanol; diethylamidiethanolamine, di-n- or di-iso-
Propanolamine, N-methylethanolamine, N
-Secondary monoamines such as ethylethanolamine; dimethylethanolamine, trimethylamine, triethylamine, triisopropylamine, methyldiethanolamine, tertiary monoamines such as dimethylaminoethanol; diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropyl Examples include polyamines such as amines and triethylamine.

By using the method for forming a matte anion electrodeposition coating film of the present invention, it is possible to easily obtain a design property in which the L value is in the range of 10 to 25 in the coating film evaluation item, and the following variation of the coating conditions is given. The degree of matte can be varied by

The energization conditions for the aqueous solution (II) are 10 to
At a water temperature of 35 ° C., a voltage of 10 to 350 V, preferably 10
Higher alkylaryl sulfonic acids can be deposited in the uncured coating film by applying an electric current for 1 to 300 seconds in the range of 0 to 250V.

As the energizing method, the first step is 10
After applying a voltage of ~ 150V, the second step is 150
Using the two-stage energization method of applying a voltage of ~ 300V,
Higher alkylaryl sulfonic acids permeate deeper into the uncured coating at the first low voltage, and higher alkylaryl sulfonic acids can be easily deposited on the coating with high film resistance at the next high voltage. It has been found that it contributes to the improvement of the coating film performance by increasing the shift to.

[0057]

EFFECTS OF THE INVENTION Anion type electrodeposition coating (I) is electrodeposited on an aluminum alloy, and at least one higher alkylaryl sulfonic acid is added in an amount of 1 equivalent or more of a basic compound in an uncured coating film. By immersing it in an aqueous solution (II) with a pH of 7.1-14, applying electricity, washing with water, and baking and drying, a coated product with excellent finish, die mark concealing property, coating performance, and low temperature curability can be obtained. To be Although the reason why the effects of the present invention are obtained is not clear, the solubility parameter of the vinyl copolymer resin as the base resin and the melamine resin as the crosslinking agent or the resin as the blocked isocyanate compound is 0.5 to 1.5. It is considered that the difference in the above is affected by the aqueous solution (II) having a pH of 7.1 to 14 and a matte coating film is obtained.

[0058]

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".

Production Example 1 280 g of isopyr alcohol was charged into a reaction vessel and kept at 80 ° C., while 40 g of styrene, 96 g of methyl methacrylate, 40 g of n-butyl acrylate, 120 g of ethyl acrylate, 48 g of 2-hydroxyethyl acrylate, and acrylic. A mixture of 28 g of acid and 8 g of azobisdimethylvaleronitrile was added dropwise over 3 hours,
Then add 4 g of azobis dimethyl valeronitrile,
The reaction was carried out at 80 ° C. for 1 hour to obtain a vinyl copolymer resin. The vinyl copolymer resin has a weight average molecular weight of about 25,000, an acid value of 55 mgKOH / g, and a hydroxyl value of 58.
It was mgKOH / g.

Production Example 2 Emulsion N
o. Production Example 1 of Vinyl Copolymer Resin Made in Production Example 1 0.4 parts of triethylamine was added to 70 parts (solid content) of the carboxyl group, and then mixed and dispersed, and then Nilacac M.
After mixing and dispersing 30 parts of X430 (Note 1), deionized water was gradually added dropwise while stirring, and triethylamine was added to adjust the pH to 7.5. Got 1. Resin No. The difference in the solubility parameter between 1 and Nicalac MX430 was 0.7.

Production Example 3 Emulsion N
o. Production Example 2 of Vinyl Copolymer Resin No. 1 70
0.4 equivalents of triethylamine with respect to parts (solid content) of the carboxyl group are mixed and dispersed, and then 20 parts of Nicalac MX430 (Note 1), Duranate 24A
-90CX (Note 2) 12.5 parts (solid content 10 parts) were mixed and dispersed, then deionized water was gradually added dropwise while stirring, and triethylamine was added so that the pH became 7.5, Emulsion No. 10% solid content Got 2. The difference in solubility parameter between the vinyl copolymer resin and the Nylacak MX430 / Duranate 24A-90CX was 0.6.

Production Example 4 Emulsion N
o. Production Example 3 of Vinyl Copolymer Resin No. 1 70
0.4 equivalents of triethylamine with respect to parts (solid content) of the carboxyl group are mixed and dispersed, and then 10 parts of Nicalac MX430 (Note 1), Duranate 24A
-90 CX (Note 2) 25 parts (solid content 20 parts) were mixed and dispersed, then deionized water was gradually added dropwise while stirring, and triethylamine was added to adjust the pH to 7.5, and solid content was added. 10% emulsion No. Got 3.
The difference in solubility parameter between the vinyl copolymer resin and the Nylacak MX430 / Duranate 24A-90CX is 0.
It was 3.

(Note 1) Nikalac MX430: Sanwa Chemical Co., Ltd., trade name, butoxylated melamine resin, solid content 100% (Note 2) Duranate 24A-90CX: Asahi Kasei Corporation's trade name, block polyisocyanate , 80% solids.

Production Example 5 The above 10% emulsion No. 13,000 parts, and then triethylamine was added to adjust the pH to 8.5, and anion electrodeposition paint No. 1 was added. Got 1.

Production Example 6 The above 10% emulsion No. 23,000 parts, triethylamine was added to adjust the pH to 8.5, and anion electrodeposition paint No. 2 was added. Got 2.

Production Example 7 The above 10% emulsion No. 3 3000 parts, triethylamine was added so that the pH was 8.5, and anion electrodeposition paint No. 3 was added. Got 3.

Production Example 8 10 parts of Taycure AC-901 (trade name, dinonylnaphthalenesulfonic acid, manufactured by Teika Co., Ltd.) was dissolved in 90 parts of isopropyl alcohol, and 0.28 parts of triethylamine (0.5 equivalent) was added to 100 parts of this solution. Equivalent to) was added. Further, deionized water was added to obtain 1000 parts of an aqueous solution having a solid content of 1%. This aqueous solution No. PH of 1 is 9.0
Met.

Production Example 9 20 parts of Taycure AC-330 (trade name, pentadecylbenzenesulfonic acid, manufactured by Teika Co., Ltd.) was dissolved in 80 parts of isopropyl alcohol, and 0.34 parts of triethylamine (0.5 equivalent) was added to 100 parts of this solution. Equivalent)
Was added. Further, deionized water was added to obtain 1000 parts of an aqueous solution having a solid content of 1%. This aqueous solution No. The pH of 2 was 8.5.

Production Example 10 20 parts of Taycure AC-430 (trade name, dodecylbenzenesulfonic acid, manufactured by Teika Co., Ltd.) was dissolved in 80 parts of isopropyl alcohol, and 0.37 part of triethylamine (0.5 equivalent) was added to 100 parts of this solution. Equivalent to) was added. Further, deionized water was added to obtain 1000 parts of an aqueous solution having a solid content of 1%. This aqueous solution No. The pH of 3 is 10.
It was 0.

Production Example 11 20 parts of Taycure AC-901 (trade name, dinonylnaphthalenesulfonic acid, manufactured by Teika Co., Ltd.) was dissolved in 80 parts of isopropyl alcohol, and 0.25 parts of triethylamine (0.2 equivalent) was added to 100 parts of this solution. Equivalent to) was added. Further, deionized water was added to obtain 1000 parts of an aqueous solution having a solid content of 1%. This aqueous solution No. PH of 4 is 3.5
Met.

Production Example 12 20 parts of Taycure AC-330 (trade name, pentadecyl sulfonic acid, manufactured by Teika Co., Ltd.) was dissolved in 80 parts of isopropyl alcohol, and 0.14 parts of triethylamine (to 0.2 equivalents) was added to 100 parts of this solution. Equivalent) was added. Further, deionized water was added to give an aqueous solution having a solid content of 1% 10
I got 00 parts. This aqueous solution No. The pH of 5 was 3.0.

Preparation of test plate An aluminum alloy (# 5000) was subjected to secondary electrolytic treatment (degreasing-etching-neutralization-anodic conversion treatment-sealing) and anodizing treatment was performed to a film thickness of about 10 μm. (Silver: size 150 × 70 × 0.5 mm) was obtained.

Example 1 Anion electrodeposition paint No. 1 obtained in Production Example 1 was prepared using two test plates. 1 and was subjected to electrodeposition coating so that the dry film thickness was 18 μm. Next, the aqueous solution N obtained in Production Example 3
o. 1 is energized at a voltage of 150 V for 1 minute, washed with water, then 160
Baking was carried out at two levels of -30 ° C for 30 minutes and 180 ° C for 30 minutes.

Examples 2 to 4 in the combinations as shown in Table 1,
The results as in Comparative Examples 1 to 3 were obtained.

[0075]

[Table 1] (Note 3) Smoothness of coating film: The surface of the coating film (wrinkle skin, unevenness, etc.) was visually evaluated. Using a coated plate which was baked at 180 ° C. ⊚ is good, ◯ is almost good, Δ is a little bad, ×
Indicates a defect.

(Note 4) Dice mark hiding property (visual evaluation): Visual inspection using a coated plate baked at 180 ° C .: ◯: Good dice mark hiding property, Δ: Inferior dice mark hiding property, ×: Die Mark hiding property is extremely poor.

(Note 5) Dice mark concealing property (L value evaluation): For baking, a coated plate applied at 180 ° C. was used, and a goniospectrophotometer GCMS-4 (trade name, manufactured by Murakami Color Research Institute).
Was used at an incident angle of 90 degrees. According to the coating film forming method of the present invention, a matte coating film having an L value in the range of 10 to 25 can be easily obtained.

(Note 6) Low temperature curing property: Acetone was soaked in gauze and reciprocated 20 times on the coated surface to check the coated surface condition. ○: No problem Δ: The coated surface melts and becomes cloudy white ×: The coated surface Dissolution is remarkable.

(Note 7) Water resistance: The test plate was immersed in warm water at 40 ° C. for 2 hours.
It was dipped for 40 hours, and a cross cut was put in, and a peeling test was performed using an adhesive tape. ◎: No peeling and no problem ○: No peeling, but some blistering near the cut part △: Partial peeling from the cross cut part Seen x: All peeled from the cross cut part.

[Brief description of drawings]

FIG. 1 is a model diagram of an anion electrodeposition tank.

[Explanation of symbols]

1. Electroplating tank (1) 2. Wash tank (1) 3. Electroplating tank (2) 4. Wash tank (2) 5. electrode 6. Washing Nords

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08F 220/20 C08F 220/20 C25D 13/06 C25D 13/06 Z 13/22 304 13/22 304B F term (Reference) 4J100 AB02S AJ02R AL03P AL09Q CA03 CA05 CA06 DA28 FA03 JA01

Claims (6)

[Claims] 1. A method for forming a matte anion electrodeposition coating film according to the following steps 1 to 4, step 1: a difference in solubility parameter between the vinyl polymer resin (A) and the crosslinking agent (B) is 0.5 to 1. A step of applying an anionic electrodeposition coating composition (I) containing a vinyl polymer resin (A) of 0.5 and a cross-linking agent (B) dispersed in water to an aluminum alloy by electrodeposition coating; A step of immersing the uncured coating film in an aqueous solution (II) having a pH of 7.1 to 14 and containing at least one higher alkylaryl sulfonic acid added in an amount of 1 equivalent or more of a basic compound; 3: Process of washing with pure water, industrial water, or recovery liquid, Process 4: Process of baking and drying. 2. A two-step energization method in which an energization condition in the aqueous solution (II) is such that a voltage of 10 to 150 V is applied as a first step and then a voltage of 150 to 300 V is applied as a second step. Item 5. The method for forming a matte anion electrodeposition coating film according to Item 1. 3. A vinyl copolymer resin (A) is radically copolymerized with a hydroxyl group-containing unsaturated monomer (a), a carboxyl group-containing unsaturated monomer (b), and another radically polymerizable unsaturated monomer (c). Claim 1 or 2 obtained by
The method for forming a matte anionic electrodeposition coating film according to. 4. The matte anionic electrodeposition coating composition according to any one of claims 1 to 3, wherein the crosslinking agent (B) is an amino resin curing agent and / or a blocked isocyanate compound. 5. A higher alkylaryl sulfonic acid is
The matte anion electrodeposition coating film forming method according to any one of claims 1 to 4, which is dinonylnaphthalene sulfonic acid and / or dinonyl naphthalene disulfonic acid. 6. A coated article in which the L value of the matte coating film obtained by the method for forming an anion electrodeposition coating film according to any one of claims 1 to 5 is in the range of 10 to 25.