JP2007009059A - Anionic electrodeposition coating and method for forming coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an anionic electrodeposition coating that has excellent low-temperature curability, finishing properties, chemical resistance, weather resistance and adhesiveness of topcoating film. <P>SOLUTION: The anionic electrodeposition coating comprises 0.1-15 mass% of a specific compound (C) based on 100 parts wt. of total of solid of a resin (A) containing a hydroxy group and a carboxy group and a blocked polyisocyanate compound (B). The anionic electrodeposition coating comprises 100 parts wt. of total of solid of a resin (A) containing a hydroxy group and a carboxy group and a blocked polyisocyanate compound (B) and 0.1-60 parts by mass of a pigment component (E). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an anionic electrodeposition paint excellent in low-temperature curability, finish, chemical resistance, weather resistance, and adhesion of a top coat film, and a coating film forming method using the anion electrodeposition paint.

Conventionally, anodized (anodized) aluminum material is lightweight and excellent in strength and corrosion resistance. After molding, it is electrodeposited with an acrylic resin / melamine curable anion electrodeposition paint. It is used for building materials, for example, aluminum sashes, joinery, base materials for verandas, roofing materials, shutters, doors, shojis, door pockets, and solariums.

  The forming process of the aluminum material is usually performed by heating and melting a cylindrical aluminum ingot, and then putting the melt into an extruder and pressing the die into a die having a hole with a predetermined cross-sectional shape. A mold material having a predetermined shape is obtained.

  Recently, with the revision of the standard of anion electrodeposition coatings on aluminum sashes, there is a demand for thinning of anion electrodeposition coatings. However, when the dry film thickness is 7 μm or less, there is a problem that the finish, chemical resistance, weather resistance, and adhesion of the top coat film are remarkably reduced. Furthermore, in the anion electrodeposition coating material that forms a matte coating film, there is a problem that the die mark of the aluminum mold material is easily noticeable and the commercial value is inferior. In consideration of energy saving, low temperature curing at the baking temperature is required.

  Conventionally, an anodized aluminum material is electrodeposited with an anionic electrodeposition coating composition containing a hydroxyl group- and carboxyl group-containing resin, a blocked polyisocyanate compound, and an organic tin catalyst. It is disclosed that the performance is good (Patent Document 1). In addition, a matte anionic electrodeposition coating material containing an aqueous resin, an amino resin curing agent and / or a blocked isocyanate compound is disclosed, and the evaluation results of the coating performance when the anion electrodeposition coating film has a dry film thickness of 18 μm are disclosed. It is described that it is good (Patent Document 2). However, in Patent Document 1 and Patent Document 2, an aluminum member having a dry film thickness of 7 μm or less of the anion electrodeposition coating film is required to be improved because the finish, chemical resistance, weather resistance, and adhesion of the top coat film are lowered. It was done.

JP-A-8-41380 JP 2003-292879 A

  The present invention is applicable to anion electrodeposition coatings having a dry film thickness of 7 μm or less, an anion electrodeposition that is excellent in low-temperature curability, finish, chemical resistance, weather resistance, adhesion of top coat, and dice mark concealment. Is to provide paint.

 As a result of intensive studies to solve the above-described problems, the present inventors have found that a resin (A) containing a hydroxyl group and a carboxyl group, a blocked polyisocyanate compound (B), and a specific compound (C). Even with a dry film thickness of 7 μm or less depending on the contained anion electrodeposition coating, it has excellent finish, chemical resistance, weather resistance and adhesion of the top coat film at low temperature baking. The inventors found that the dice mark is excellent in concealment, and have completed the invention.

  Even if the dry film thickness is 7 μm or less by low-temperature baking by the anion electrodeposition coating material of the present invention and the coating film forming method using the anion electrodeposition coating material, the finish, chemical resistance, weather resistance, and adhesion of the top coating film An anionic electrodeposition coating film having excellent resistance is obtained. Furthermore, a matte anion electrodeposition coating film having excellent concealing ability for dice marks can be obtained.

  According to the present invention, it is an anionic electrodeposition paint containing a resin (A) containing a hydroxyl group and a carboxyl group, a blocked polyisocyanate compound (B), and a compound (C) represented by the following formula (1).

Formula (1)
(R ¹ is the same or different alkyl group having 1 to 10 carbon atoms, or phenyl group, R ² is the same or different hydrogen atom or methyl group, and n is an integer of 15 to 80. Showing).

  Examples of the anionic electrodeposition coating material of the present invention include anodized aluminum, magnesium, titanium building materials, electrical products, automobile parts, and the like. Hereinafter, the anion electrodeposition coating material of the present invention will be described in detail.

Resin (A) containing hydroxyl group and carboxyl group:
The resin (A) containing a hydroxyl group and a carboxyl group is a resin having at least one carboxyl group in one molecule and having at least one hydroxyl group. Specific examples include resins such as acrylic resins, polyester resins, polyether resins, polycarbonate resins, and urethane resins. Among these, acrylic resins are preferred from the viewpoint of weather resistance. The acrylic resin includes a carboxyl group-containing radical polymerizable unsaturated monomer (a ₁ ), a hydroxyl group-containing radical polymerizable unsaturated monomer (a ₂ ), and other radical polymerizable unsaturated monomers (a It can be produced by copolymerizing ₃ ).

Examples of the carboxyl group-containing radical polymerizable unsaturated monomer (a ₁ ) include monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid.

Examples of the hydroxyl group-containing radical polymerizable unsaturated monomer (a ₂ ) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4- Hydroxybutyl (meth) acrylate, and in addition, Plaxel FM1 (manufactured by Daicel Chemical Industries, trade name, caprolactone-modified (meth) acrylic acid hydroxy esters), Plaxel FM2 (same as left), Plaxel FM3 (same as left), Plaxel FA1 (same as left) ), Plaxel FA2 (same as left), Plaxel FA3 (same as left), and the like.

Examples of the other radical polymerizable unsaturated monomer (a ₃ ) include N- (2-hydroxyethyl) (meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide, and N- (3 -Hydroxypropyl) (meth) acrylamide, N-methyl-N- (2-hydroxyethyl) (meth) acrylamide, N-ethyl-N- (2-hydroxyethyl) (meth) acrylamide, N-methyl-N- ( 2-hydroxypropyl) (meth) acrylamide, N-methyl-N- (3-hydroxypropyl) (meth) acrylamide, N-ethyl-N- (2-hydroxypropyl) (meth) acrylamide, N-ethyl-N- (3-hydroxypropyl) (meth) acrylamide, N, N-di- (2-hydroxyethyl) (meth) ac Ruamido, N, N-di - (2-hydroxypropyl) (meth) nitrogen-containing radical-polymerizable unsaturated monomer acrylamide.

  For example, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinyltripropoxysilane, vinylmethyldipropoxysilane, vinyldimethylpropoxysilane, γ- Examples include alkoxysilyl group-containing radical polymerizable unsaturated monomers such as (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, and γ- (meth) acryloxypropyldimethylmethoxysilane. .

  For example, divinylbenzene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol diacrylate, glycerol di (meth) acrylate, glycerol tri (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, penta Erythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentylglycol Diacrylate, 1,6-hexanediol diacrylate, glycerol allyloxydi (meth) acrylate, 1,1,1-tris (hydroxymethyl) ethanedi (meth) acrylate, 1,1,1-tris (hydroxymethyl) ethanetri Examples thereof include monomers having two or more radically polymerizable unsaturated bonds in one molecule such as (meth) acrylate.

For example, N-methylolacrylamide, N-methoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide, Ni-propoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, Ni-butoxy And methyl (meth) acrylamide. Other radically polymerizable unsaturated monomers (a ₃ ) can be used alone or in combination of two or more as appropriate.

The blending ratio of these monomers is such that the carboxyl group-containing radical polymerizable unsaturated monomer is based on the total solid content of the radical polymerizable unsaturated monomer constituting the resin (A) containing a hydroxyl group and a carboxyl group. The monomer (a ₁ ) is 2 to 40% by mass, preferably 4 to 30% by mass, the hydroxyl group-containing radical polymerizable unsaturated monomer (a ₂ ) is 3 to 50% by mass, preferably 5 to 40% by mass, The other radical polymerizable unsaturated monomer (a ₃ ) is preferably 10 to 90% by mass, and more preferably 20 to 70% by mass.

  Examples of the solvent used for the polymerization reaction include alcohols such as propyl alcohol, isopropyl alcohol, n-butyl alcohol, t-butyl alcohol, isobutyl alcohol, diethylene glycol monobutyl ether, methyl carbitol, 2-methoxyethanol, 2-ethoxy. Ethanol, 2-isopropoxyethanol, 2-butoxyethanol, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, 1-methoxy-2-propanol, 1-ethoxy-2-propanol Ethers such as dipropylene glycol monomethyl ether can be preferably used.

  Other than these, for example, aromatics such as xylene and toluene; ketones such as acetone, methyl ethyl ketone, 2-pentanone, 2-hexanone, methyl isobutyl ketone, isophorone, and cyclohexanone; methyl acetate, ethyl acetate, Esters such as pentyl acetate, 3-methoxybutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl propionate and ethyl propionate can also be used in combination.

  Examples of the radical polymerization initiator used for radical copolymerization include, for example, benzoyl peroxide, di-t-butyl hydroperoxide, t-butyl hydroperoxide, cumyl peroxide, cumene hydroperoxide, diisopropylbenzan hydroperoxide, Peroxides such as t-butylperoxybenzoate, lauryl peroxide, acetyl peroxide, t-butylperoxy-2-ethylhexanoate, α, α'-azobisisobutylnitrile, azobisdimethylvaleronitrile, azo Examples include azo compounds such as biscyclohexanecarbonitrile. The weight average molecular weight (Note 1) of the acrylic resin produced as described above is in the range of 5,000 to 150,000, preferably 20,000 to 100,000.

  (Note 1) Weight average molecular weight: Measured according to JIS K 0124-83, using TSK GEL4000HXL + G3000HXL + G2500HXL + G2000HXL (manufactured by Tosoh Corporation) as a separation column at a flow rate of 1.0 ml / min at 40 ° C. It calculated | required by calculation from the chromatograph obtained by RI refractometer and the calibration curve of polystyrene using tetrahydrofuran for GPC.

Blocked polyisocyanate compound (B):
As the blocked polyisocyanate compound, those obtained by blocking the isocyanate group of a conventionally known polyisocyanate compound with a blocking agent can be used. Examples of the polyisocyanate compound include aliphatic diisocyanates such as hexamethylene diisocyanate or trimethylhexamethylene diisocyanate; cyclic aliphatic diisocyanates such as hydrogenated xylylene diisocyanate or isophorone diisocyanate; tolylene diisocyanate or 4,4′-diphenylmethane diisocyanate. An organic diisocyanate itself such as an aromatic diisocyanate itself, or an adduct of each of these organic diisocyanates with a polyhydric alcohol, a low molecular weight polyester resin or water, or a cyclic polymer of each organic diisocyanate as described above, Furthermore, an isocyanate biuret body etc. are mentioned.

  As specific commercial products of the block polyisocyanate compound (B), Bernock D-750, -800, DN-950, -970 or 15-455, (manufactured by Dainippon Ink & Chemicals, trade name), Death Module L, N, HL, IL or N3390 (above, manufactured by Bayer Corporation), Takenate D-102, -202, -110N or 123N (Takeda Pharmaceutical Company Limited, trade name), Coronate L, HL, EH Alternatively, 203 (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.), Duranate 24A-90CX, Duranate TPA-B80 (trade name, manufactured by Asahi Kasei Chemicals Corporation), and the like can be given.

  The anionic electrodeposition paint can be used in combination with a melamine resin. Examples of the melamine resin include a methylolated melamine resin obtained by methylolating melamine with formaldehyde; an alkylated melamine resin obtained by etherifying this methylol group with a monoalcohol; a methylolated melamine resin having an imino group or an alkylated melamine resin. Can do.

  Further, in the etherification of the methylol group, a mixture alkylated using two or more monoalcohols may be used. Examples of the monoalcohol include methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, 2-ethylbutanol, 2-ethylhexanol and the like. Specifically, methylated melamine resin, imino group-containing methylated melamine resin, methylated / butylated melamine resin, imino group-containing methylated / butylated melamine resin, and the like are used.

  Specific commercial products of the above melamine resins include Uban 20SE-60, Uban 225 (all are trade names manufactured by Mitsui Chemicals, Inc.), Super Becamine G840, Super Becamine G821 (and all are Dainippon Butyl etherified melamine resins such as Ink Chemical Industries, Ltd. (trade name); Sumimar M-100, Sumimar M-40S, Sumimar M-55 (all of which are trade names made by Sumitomo Chemical Co., Ltd.), Cymel 232, Cymel 303, Cymel 325, Cymel 327, Cymel 350, Cymel 370 (all of which are made by Nippon Cytec Industries, Inc., trade name), Nicarak MS17, Nicarak MX15, Nicarak MX430, Nicarak MX600 (all of which are all made by Sanwa Chemical Co., Ltd.) Name) Resimin 741 (M Methyl etherified melamine resins such as Santo Co., Ltd. (trade name); Cymel 235, Cymel 202, Cymel 238, Cymel 254, Cymel 272, Cymel 1130 (all of which are Mitsui Cytec Co., Ltd., trade name), Summir M66B (Sumitomo) Mixed etherified melamine resin of methylation and isobutylation, etc., manufactured by Kagaku Co., Ltd .; methylation of Cymel XV805 (trade name, manufactured by Mitsui Cytec Co., Ltd.), Nicalac MS95 (trade name, manufactured by Sanwa Chemical Co., Ltd.), etc. And n-butylated mixed etherified melamine resin.

  As a compounding ratio of the resin (A) containing a hydroxyl group and a carboxyl group and the blocked polyisocyanate compound (B), the resin (A) containing a hydroxyl group and a carboxyl group is 25 to 75% by mass, preferably 40 to 40%. The range of 60% by mass and the blocked polyisocyanate compound (B) in the range of 10 to 60% by mass, preferably 20 to 40% by mass is also preferable for low temperature curability and coating stability.

Compound (C):
The anion electrodeposition paint of the present invention is
It contains a compound (C) represented by the following formula (1).

Formula (1)
(R ¹ is the same or different alkyl group having 1 to 10 carbon atoms, or phenyl group, R ² is the same or different hydrogen atom or methyl group, and n is an integer of 15 to 80. Showing).

Specifically, Sannics PP-1000, Sannix PP-2000, Sannix PP-3000, Sannix PP-4000 (above, Sannix series, manufactured by Sanyo Chemical Industries, Ltd., polyoxypropylene glycol) may be mentioned.
By adding the compound (C), a dry film thickness of 7 μm or less, preferably a dry film thickness of 1 to 7 μm, more preferably a dry film thickness of 3 to 6 μm, finish, chemical resistance, weather resistance and adhesion of the top coat film Can be obtained.

  The compounding ratio of the compound (C) in the anionic electrodeposition coating is based on the total solid content of 100 parts by weight of the resin (A) containing a hydroxyl group and a carboxyl group and the blocked polyisocyanate compound (B) (C ) Is preferably in the range of 0.1 to 15 parts by mass, preferably 0.5 to 5 parts by mass, and more preferably 1 to 3 parts by mass from the viewpoints of coating stability, finish, and adhesion of the top coat film.

  The reason why the anion electrodeposition coating film to which the compound (C) is added is excellent in finish and adhesion to the top coating film is that the compound (C) is a resin (A) or block containing a hydroxyl group and a carboxyl group. Excellent compatibility with the modified polyisocyanate compound (B) and heat flow of the coating during baking and drying. For this reason, the obtained anion electrodeposition coating film has excellent finish, and further, the compound (C) is easily oriented on the surface of the anion electrodeposition coating film, thereby providing an adhesion active point with the top coating film. Therefore, it is considered that the adhesion with the top coating film on the anion electrodeposition coating film is excellent.

Organotin compound (D):
An organic tin compound (D) can be appropriately added to the anionic electrodeposition paint of the present invention to improve chemical resistance and low-temperature curability. Specific commercial products include trade names of Nitto Kasei Co., Ltd .; T-100, U-100, U-130, U-15, U-20, U-200, U-220, U-230, U-28. U-300, U-303, U-317, U-340U-400, U-50, U-500, U-550, U-700, U-700ES, U-8, U-800, U-810 U-830, U-ES, U-280, U-350, U-360, U-840, U-850, U-860, U-870, etc., trade names manufactured by Sansha Co., Ltd .; SCAT-1 , SCAT-1W, SCAT-4A, SCAT-7, SCAT-8, SCAT-8B, SCAT-24, SCAT-25, SCAT-27, SCAT-31A, SCAT-32A, SCAT-46A, SCAT-51, SCAT -52A, no. 918, STANNBL, STANNSNT-1F, etc., trade names made by Sumika Bayer Urethane Co., Ltd .; Desmolapide PA, Desmolrapid SO and the like can be mentioned, but are not limited thereto.

  Examples of organometallic compounds other than the organotin compound (D) include organic bismuth compounds such as bismuth lactate and octix bismuth, titanate compounds such as tetrabutyl titanate, tetraisopropyl titanate, and triethanolamine titanate, lead octylate, and naphthene. Carboxylic acid metal salts such as lead acid, nickel naphthenate, lithium naphthenate and cobalt naphthenate, metal acetylacetonate complexes such as aluminum acetylacetonate complex and vanadium acetylacetonate complex, trade name manufactured by Nitto Kasei Co., Ltd .; U-600 U-660 and the like, but are not limited thereto.

For the anionic electrodeposition coating, the water dispersion of the carboxyl group-containing resin of the resin (A) containing a hydroxyl group and a carboxyl group is performed by adding 0.1 to 1.2 equivalents of a basic compound and deionized water as a neutralization equivalent. An emulsion can be obtained while stirring with a disper or the like.

  The basic compounds used for neutralization of the resin (A) containing a hydroxyl group and a carboxyl group are ethylamine, propylamine, butylamine, benzylamine, monoethanolamine, neopentanolamine, 2-aminopropanol, 3-amino. Primary monoamines such as propanol; secondary monoamines such as diethylamidiethanolamine, di-n- or di-iso-propanolamine, N-methylethanolamine, N-ethylethanolamine; dimethylethanolamine, trimethylamine, triethylamine, Tertiary monoamines such as triisopropylamine, methyldiethanolamine, dimethylaminoethanol; diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropyl Examples include polyamine triethylamine such as propylamine.

Pigment component (E):
The anionic electrodeposition paint can be blended with the pigment component (E) as required. By blending the pigment component (E), an effect of being excellent in design properties and top coat adhesion can be obtained.
Specific examples of the pigment component (E) include color pigments such as titanium dioxide, red pepper, carbon black, yellow iron oxide (ocher), copper phthalocyanine blue, copper phthalocyanine green, clay (kaolin), talc, calcium carbonate. An extender pigment such as barium sulfate, silica, diatomaceous earth, and magnesium carbonate can be used.
It is preferable to add a surfactant and water to the pigment component (E) and prepare in advance a pigment dispersion paste that is dispersed using a ball mill, a sand mill, or the like, and use it in the production of an anionic electrodeposition paint.

  The anion electrodeposition coating is produced by adding a neutralizing agent or water to a resin (A) containing a hydroxyl group and a carboxyl group (A), a blocked polyisocyanate compound (B) and a compound (C) and dispersing in water. It can be obtained by adding a pigment dispersion paste and adjusting the solid content to 5 to 30% by mass with deionized water.

Film formation method To obtain an aluminum member having an anion electrodeposition coating film , an anodized electrodeposition electrodeposition coating is applied to the anodized aluminum material, and the paint is baked and cured without being washed or washed with water. Is obtained.

  The formation of a coating film by anionic electrodeposition coating is usually performed by placing an anionic electrodeposition paint in an electrodeposition bath to form an electrodeposition bath, immersing the aluminum substrate in this bath, and then the dry film thickness after baking. Anion electrodeposition coating is performed so that the thickness is about 30 μm or less, preferably 1 to 7 μm, more preferably 3 to 6 μm, and washing with water (non-rinsing) or washing with water (rinsing) is performed. Subsequently, after setting at room temperature, it can carry out by baking and hardening. The baking conditions are usually about 130 to 200 ° C., preferably 140 to 160 ° C., and about 15 to 50 minutes, preferably 15 to 30 minutes.

  The coating film using the anion electrodeposition coating material of the present invention is excellent in finish, chemical resistance, weather resistance, and adhesion of the top coating film even at a dry film thickness of 7 μm or less by low-temperature baking at 160 ° C. or less. Furthermore, in the anionic electrodeposition coating material that forms a matte coating film, a coating film having the above-mentioned coating film performance and having a 60-degree specular gloss (see Note 13 below) of 10 or less and excellent in dice mark concealing properties. can get.

Multilayer coating film forming method A top coating material can be applied to the surface of the coating film of the anionic electrodeposition coating material of the present invention. As the top coating material, a coating material which is already known per se, mainly composed of a base resin and a curing agent can be used. It is also possible to wash the anionic electrodeposition coating film with water and set it at room temperature, then apply the top coating without curing and bake and cure both coatings at the same time to obtain a multilayer coating film. .

  Examples of the base resin of the top coating include acrylic resins, polyester resins, alkyd resins, epoxy resins, urethane resins, silicone resins, fluorine resins, and modified products thereof, amino resins, (block )) A top coating composition containing a polyisocyanate compound.

The type of the paint may be any of a solution-type paint using an organic solvent medium, a non-aqueous dispersion paint, a water-soluble and / or emulsion paint and a powder paint using water as a medium. Good.
The top coating is applied to the surface of the anion electrodeposition coating film by a usual coating means such as brush coating, spray coating, dip coating, flow coating, roller coating, electrostatic spray coating, and then dried (including heating). ) To form a coating film. The applied film thickness varies depending on the required performance, but is usually in the range of about 10 to 100 μm in terms of dry film thickness. The drying can be performed at room temperature or by heating, but it is desirable to set conditions suitable for the type of paint. The anion electrodeposition coating film of the present invention provides an anion electrodeposition coating film having a dry film thickness of 0.1 to 7 μm and excellent adhesion of the top coating film.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited thereby. “Parts” and “%” indicate “parts by mass” and “% by mass”.
Production Example 1 Acrylic resin solution No. 1 Production Example 1 In a reaction vessel, 143 parts of isopropyl alcohol was charged and maintained at 80 ° C., and the following “mixture (A)” was added dropwise over 3 hours, and then 1 part of azobisdimethylvaleronitrile was added. And the reaction was carried out by holding at 85 ° C. for 4 hours to obtain an acrylic resin solution No. 70 having a solid content of 70% by mass. 1 was produced.
"Mixture (A)"
Styrene 10 parts Methyl methacrylate 31 parts n-Butyl acrylate 10 parts Ethyl acrylate 30 parts Acrylic acid 7 parts 2-Hydroxyethyl acrylate 12 parts Azobisdimethylvaleronitrile 2.1 parts The acrylic resin solution no. 1 had a weight average molecular weight of about 25,000, an acid value of 55 mgKOH / g, and a hydroxyl value of 58 mgKOH / g.

Production Example 2
Into a reaction vessel, 143 parts of isopropyl alcohol was charged and maintained at 80 ° C., and the following “mixture (B)” was added dropwise over 3 hours, then 1 part of azobisdimethylvaleronitrile was added, and 85 The reaction was carried out by holding at 4 ° C. for 4 hours to obtain an acrylic resin solution No. 70 having a solid content of 70% by mass. 2 was produced.
"Mixture (B)"
Styrene 15 parts Methyl methacrylate 31 parts KBM-503 (Note 2) 3 parts n-Butyl acrylate 19 parts Ethyl acrylate 10 parts Acrylic acid 7 parts 2-Hydroxyethyl acrylate 15 parts Azobisdimethylvaleronitrile 2.1 parts The acrylic resin solution No. 2 had a weight average molecular weight of about 30,000, an acid value of 53 mgKOH / g, and a hydroxyl value of 72 mgKOH / g.
(Note 2) KBM-503: manufactured by Shin-Etsu Silicone, trade name, γ-methacryloyloxypropyltrimethoxysilane.

Production and Production Example 3 of Anion Electrodeposition Paint (Clear) Emulsion No. Production of 70% acrylic resin solution No. 1 obtained in Production Example 1 above. 1 part 100 parts (solid content 70 parts), Duranate TPA-B80 (Note 3) 37.5 parts (solid content 30 parts), Sannix PP-4000 (Note 6) 1 part, SCAT-7 (Note 7) 3 parts (1.5 parts solids) and 1.9 parts triethylamine (0.4 neutralization equivalents) were added and dispersed in water, followed by 158.1 parts deionized water and anion electrodeposition with a solid content of 34%. Emulsion No. for paint 1 was obtained.

Production Examples 4 to 10 Emulsion No. 2-No. 8 Anion electrodeposition coating emulsion No. 8 was prepared in the same manner as in Production Example 3 except that the content of blending was changed to Table 1. 2-No. 8 was obtained.

(Note 3) Duranate TPA-B80: Asahi Kasei Chemicals, trade name, isocyanurate of hexamethylene isocyanate, methyl ethyl ketoxime blocking agent (Note 4) Cymel 232: Mitsui Cytec, trade name, methyl / butyl mixed ether Melamine resin)
(Note 5) SANNICS PP-1000: Sanyo Chemical Industries, trade name, polypropylene glycol, molecular weight 1,000
(Note 6) Sannics PP-4000: Sanyo Chemical Industries, trade name, polypropylene glycol, molecular weight 4,000
(Note 7) SCAT-7: Sansha Co., Ltd., trade name, dibutyltin bis (mercaptocarboxylic acid ester).

Preparation of coated material An aluminum material (silver: size: 150 mm × 70 mm × 0.5 mm) having a film thickness of about 10 μm subjected to primary electrolytic treatment (degreasing-etching-neutralization-anodizing treatment-sealing) Used as an object to be coated.

Example 1
Emulsion No. 2 for anionic electrodeposition paint obtained in Production Example 3. 301.5 parts (solid content 102.5 parts) and deionized water 979.5 parts were added, and the anionic electrodeposition paint No. 1 having a solid content of 8% was added. 1 was obtained.
To the aluminum material, an anionic electrodeposition paint No. No. 1 was subjected to electrodeposition coating under a coating condition such that the dry film thickness was 7 μm. Then, after washing with water, setting was performed at room temperature for 3 minutes, followed by heat drying at 150 ° C. for 20 minutes with a hot air dryer, and anion electrodeposition coating No. 1 test plate was obtained. Anionic electrodeposition paint No. Table 3 shows the film thickness of 1 and the test results.

Examples 2-4, Comparative Examples 1-4
Anionic electrodeposition paint No. 1 with the formulation as shown in Table 2. 2-No. 8 was obtained. As in Example 1, an anionic electrodeposition paint No. 2-No. 8 test plates were obtained. Table 3 shows the film thickness and test results.

(Note 8) Finishability:
○ indicates that the coating surface is good. Δ indicates that there are a few coating defects such as crusty skin, unevenness, glossiness, repelling, unevenness, dents, or any of the following.
In x, the coating film defects such as crushed skin, unevenness, glossiness, repelling, unevenness, dents, and any of these are remarkable.

(Note 9) Chemical resistance: After immersing the test plate in a 1% nitric acid aqueous solution at 20 ° C. for 30 days, the presence or absence of coating film abnormality such as cracking, peeling or swelling of the top coating film was observed.
◎: No abnormality ○: Slightly inferior, but good for practical use △: Abnormal 異常: Remarkably abnormal.

(Note 10) Weather resistance: In accordance with JIS K5400, the gloss of the paint film is measured using a carbon arc lamp type accelerated weathering tester sunshine weatherometer, and the gloss retention ratio against the gloss before the exposure test is 80%. The time to divide was measured. Furthermore, the coating film surface was observed visually.
◎: Time for gloss retention to break 80% exceeds 3,000 hours ○: Time for gloss retention to break 80% is 2,500 hours or more and less than 3,000 hours ○ △: Gloss retention The time when the rate is less than 80% is 2,000 hours or more and less than 2,500 hours Δ is the time when the gloss retention is less than 80% is 1,000 hours or more and less than 2,000 hours,
X is less than 1,000 hours when the gloss retention is less than 80%.

(Note 11) Adhesion of top coat film (A): A test plate on which an anion electrodeposition coating film was applied, and lanthanum PG white (manufactured by Kansai Paint Co., Ltd., trade name, room temperature drying type two-component urethane paint) with a film thickness of 30 μm And dried at 20 ° C. for 7 days. Thereafter, a moisture resistance test was conducted under conditions of a temperature of 50 ° C. and a relative humidity of 90% for 240 hours.
After completion of the moisture resistance test, the test plate was left at room temperature for 1 hour, and this test plate was cut into a grid pattern at intervals of 1 mm with a cutter knife, and cello tape (registered trademark) was applied to 100 squares and peeled off. .
◎ indicates that there is no problem with the remaining squares (pieces) / total squares (pieces) = 100/100
○ means that the remaining squares (pieces) / total squares (pieces) = 95 to 100/100, and there is no problem in use in the product.
Δ is a residual cell (pieces) / total cell (pieces) = 90 to 94/100, and there is a problem in using the overcoated product. ×: remaining cell (pieces) / total cell ( Pieces) = 89 or less / 100, it is difficult to use products with overcoating.

(Note 12) Adhesion of top coat film (B): Fuccalon (trade name, fluorine-based baking curable paint, manufactured by Kansai Paint Co., Ltd.) is applied to a test plate on which an anion electrodeposition coating film has been applied to a film thickness of 30 μm. And dried at 210 ° C. for 20 minutes. Then, after being immersed in boiling water for 4 hours, it is left at room temperature for 1 hour, and this test plate is cut in a grid pattern at intervals of 1 mm with a cutter knife, and cello tape (registered trademark) is applied to 100 squares. It peeled.
◎ indicates that there is no problem with the remaining squares (pieces) / total squares (pieces) = 100/100
○ indicates that the remaining squares (pieces) / total squares (pieces) = 95 to 100/100, and there is no problem in use in the product.
Δ is a residual cell (pieces) / total cell (pieces) = 90 to 94/100, and there is a problem in using the overcoated product. ×: remaining cell (pieces) / total cell ( Pieces) = 89 or less / 100, it is difficult to use products with overcoating.

  (Note 13) 60 degree specular glossiness: When the degree of glossiness of the multilayer coating film is 60 degrees according to the 60 degree specular glossiness of JIS K-5400 7.6 (1990), respectively. The reflectance was measured and expressed as a percentage when the glossiness of the reference surface of the specular glossiness was taken as 100.

(Note 14) Dice mark concealment property: Dice mark concealment property: evaluated by visual evaluation.
○ indicates good dice mark concealment,
△ is inferior in dice mark concealment,
X is remarkably inferior in dice mark concealment.

Production and Production Example 11 of Anion Electrodeposition Paint (Colored) Production Example of Pigment Dispersion Paste Into a ball mill, 9.6 parts of 60% amine neutralized acrylic resin pigment dispersion resin (Note 15) (solid content 5.8), CR -97 (trade name, titanium white, manufactured by Ishihara Sangyo Co., Ltd.) 48.3, Todacolor KN-O (Note 16) 0.07 parts, TAROX LL50 (Note 17) 0.9 parts, and deionized water 41.2 parts Was dispersed for 20 hours to obtain a pigment dispersion paste having a solid content of 55%.

(Note 15) Amine-neutralized acrylic resin pigment dispersion resin: acrylic resin having a carboxyl group with an acid value of 54.5 mgKOH / g, a hydroxyl value of 74.2 mgKOH / g, and a weight average molecular weight of 40,000 (Note 16) Todacolor KN- O: Toda Kogyo Co., Ltd., trade name, Bengala (Note 17) TAROX LL50: Titanium Kogyo Co., Ltd., trade name, yellow iron oxide.

Example 5
Emulsion No. 2 for anionic electrodeposition paint obtained in Production Example 3 above. 301.5 parts (solid content 102.5 parts) of No. 1 and 100 parts of 55% pigment dispersion paste obtained in Production Example 11 (solid content 55.07) were added and stirred, and 911 parts of deionized water was added. Anionic electrodeposition paint No. 12 having a solid content of 12% 9 was obtained.
Next, using the aluminum material, an anionic electrodeposition paint No. After electrodeposition coating of No. 9, it was washed with water and set at room temperature for 3 minutes. Thereafter, it was dried by heating at 150 ° C. for 20 minutes in a hot air dryer. A test plate having 9 electrodeposition coating films was obtained. Table 5 shows the test results using the test plate.

Examples 6-8 and Comparative Examples 5-8
Anionic electrodeposition paints Nos. 6 to 8 and Comparative Examples 5 to 8 in the formulations shown in Table 4 were used. 10-No. 16 was obtained. Anionic electrodeposition paint No. 10-No. Table 5 shows the test results using the test plate according to No. 16.

Example 9
The above-mentioned aluminum material is coated with anionic electrodeposition paint No. No. 9 was subjected to electrodeposition coating under a coating condition of a dry film thickness of 7 μm, then washed with water and set at room temperature for 3 minutes. Next, the adhesion coating A (Note 11) of the top coating film and the adhesion B (Note 12) of the top coating film were subjected to a test without baking and curing the anion electrodeposition coating film. The test results are shown in Table 5.

Comparative Example 9
The above-mentioned aluminum material is coated with anionic electrodeposition paint No. No. 14 was subjected to electrodeposition coating under dry coating conditions of 7 μm, then washed with water and set at room temperature for 3 minutes. Next, the adhesion coating A (Note 11) of the top coating film and the adhesion B (Note 12) of the top coating film were subjected to a test without baking and curing the anion electrodeposition coating film. The test results are shown in Table 5.

The anion electrodeposition coating material of the present invention can provide an aluminum member that is excellent in finish, chemical resistance, weather resistance, and adhesion of top coat film even in a thin film having a dry film thickness of 7 μm or less in low-temperature baking at 160 ° C. or lower. .

Claims (4)

The compound (C) represented by the following formula (1) is added to the total solid content of 100 parts by weight of the resin (A) containing a hydroxyl group and a carboxyl group and the blocked polyisocyanate compound (B) by 0. Anionic electrodeposition paint containing 1 to 15% by mass.

Formula (1)
(R ¹ is the same or different alkyl group having 1 to 10 carbon atoms, or phenyl group, R ² is the same or different hydrogen atom or methyl group, and n is an integer of 15 to 80. Indicates) The pigment component (E) is contained in an amount of 0.1 to 60 parts by mass with respect to 100 parts by weight of the total solid content of the resin (A) containing a hydroxyl group and a carboxyl group and the blocked polyisocyanate compound (B). Anion electrodeposition paint described in 1. An anodized aluminum base material is electrodeposited with the anionic electrodeposition coating composition according to claim 1 or 2 to form an anionic electrodeposition coating film having a dry film thickness of 1 to 7 μm. Method. A method for forming a multilayer coating film, comprising: applying a top coating onto an uncured or cured coating film of the anion electrodeposition coating film obtained by the coating film forming method according to claim 3.