JP4776019B2 - High hardness matte electrodeposition coating composition - Google Patents

Description

  The present invention relates to an anionic matte electrodeposition coating composition, and is particularly suitable for the coating of aluminum building materials, is characterized by high hardness, and can provide an electrodeposition coating film excellent in durability and scratch resistance.

  Conventionally, anodized aluminum materials are light and strong, and are excellent in corrosion resistance. Therefore, they are widely used for building materials such as window frames, doors, and exteriors of buildings and houses. For the coating of aluminum materials, anionic electrodeposition paints with a single coat and good finish are generally used. A typical example of the anionic electrodeposition coating material is a melamine curable electrodeposition coating material prepared by blending a water-based acrylic resin containing a carboxyl group and a hydroxyl group with a melamine resin as a crosslinking agent and dispersing in water.

  However, in recent years, the required quality for aluminum building materials has become sophisticated, and in particular, in terms of scratch resistance, performance that cannot be achieved by conventional products is required. Specifically, reduction of scratches is required in every situation such as product manufacturing process, transportation process, and use site. There are various causes of scratches, such as rubbing between building materials, rubbing with spacers (corrugated cardboard, plastic, rope, etc.), rubbing with sand, dust, etc., in terms of reduced product yield or aesthetics. Building materials that have become a major problem and have excellent scratch resistance are demanded.

As a conventional technique for improving the scratch resistance, there is a technique of mixing and using a silicone material having a relatively high hardness from the viewpoint of increasing the hardness of the coating film. Patent Document 1 is a method of producing a water-dispersible vinyl copolymer in the presence of a silicate compound to obtain a base resin for a paint, and although it can certainly improve the scratch resistance, Property and weather resistance are insufficient. Patent Document 2 is a technique in which colloidal silica is used in combination with a conventional anionic electrodeposition paint, but although a matte paint film is obtained, the paint film appearance is insufficient and the chemical resistance and water resistance are poor. In Patent Document 3, it is a technique that uses organic hard resin particles in combination, but it is necessary to further increase the hardness and to improve the level of scratch resistance.
JP-A-11-315254 JP-A-11-302576 JP 2001-342425 A

  Therefore, the present invention has characteristics that are not found in conventional products in coating film hardness and scratch resistance, and coating film properties such as weather resistance, chemical resistance, solvent resistance, and mechanical properties, and a feeling of finished film and coating. It is an object of the present invention to provide a new matte electrodeposition coating composition that is excellent in workability, coating stability, and the like.

  The present invention includes (A) (a) an α, β-ethylenically unsaturated carboxylic acid monomer, (b) a hydroxyl group-containing α, β-ethylenically unsaturated monomer, and (c) an acetoacetyl group as a crosslinking functional group. (B) a vinyl copolymer having a Tg of 0 to 50 ° C. obtained by copolymerization of another α, β-ethylenically unsaturated monomer having (d), (E) The content of the α, β-ethylenically unsaturated monomer whose Tg of the homopolymer is 60 ° C. or higher and 170 ° C. or lower is 40 to 90% by weight, (f) the hydroxyl group-containing α, β-ethylenically unsaturated A vinyl copolymer containing 5 to 40% by weight of a saturated monomer, and (g) another α, β-ethylenically unsaturated monomer as the remaining part by weight, and (C) cross-linking An anionic matte electrodeposition coating composition containing an agent, and even more preferably a vinyl copolymer ( A) an anionic matte electrodeposition coating composition having an acid value of 10 to 150 KOHmg / g and a hydroxyl value of 20 to 200 KOHmg / g, and the vinyl copolymer (B) having a weight average molecular weight of 5,000 to An anionic matte electrodeposition coating composition of 50,000, wherein the vinyl copolymer (B) is preferably copolymerized with an α, β-ethylenically unsaturated carboxylic acid monomer. An anionic matte electrodeposition coating composition having a value of 5 to 100 KOHmg / g.

  By applying the electrodeposition paint of the present invention, it is possible to form a matte electrodeposition paint film having excellent properties that are not found in conventional products in film hardness and scratch resistance. In addition, the resulting coating film is excellent in weather resistance, chemical resistance, solvent resistance, mechanical properties such as mechanical properties, and finish feeling of the coating film, and the paint is also excellent in coating workability, stability over time, etc. ing.

Hereinafter, the anionic matte electrodeposition coating composition of the present invention will be described in detail.
[(A) Vinyl copolymer]
The vinyl polymer (A) used in the present invention comprises (a) an α, β-ethylenically unsaturated carboxylic acid monomer, (b) a hydroxyl group-containing α, β-ethylenically unsaturated monomer, (c) It is a vinyl copolymer obtained by copolymerizing an α, β-ethylenically unsaturated monomer having an acetoacetyl group as a cross-linking functional group, and (d) another α, β-ethylenically unsaturated monomer.

  The α, β-ethylenically unsaturated carboxylic acid monomer imparts water dispersibility and electrophoretic properties to the vinyl copolymer (A). Illustrative examples include acrylic acid, methacrylic acid, crotonic acid, vinyl acetic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid and the like. These 1 type (s) or 2 or more types can be mixed and used.

  The α, β-ethylenically unsaturated carboxylic acid monomer is used in such a range that the acid value of the vinyl copolymer (A) is 10 to 150 KOHmg / g, more preferably 20 to 100 KOHmg / g. If the acid value of the vinyl copolymer (A) is less than 10 KOH mg / g, sufficient water dispersion stability is difficult to obtain, and if it exceeds 150 KOH mg / g, the electrophoretic properties and coating film deposition properties are reduced. Water resistance and alkali resistance are reduced.

  The hydroxyl group-containing α, β-ethylenically unsaturated monomer reacts with the crosslinking agent (C) and imparts curability when the coating film is baked. Illustrative examples include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, and the like. The lactone modification | denaturation material etc. of these are mentioned, It can use 1 type or in mixture of 2 or more types.

  Such a hydroxyl group-containing α, β-ethylenically unsaturated monomer is used in such a range that the hydroxyl value in the vinyl copolymer (A) is 20 to 200 KOHmg / g, more preferably 40 to 160 KOHmg / g. Is done. When the hydroxyl value is less than 20 KOHmg / g, sufficient curability cannot be ensured, and when it exceeds 200 KOHmg / g, the coating film becomes brittle, water resistance is lowered, and sufficient performance is hardly obtained.

  In addition, α, β-ethylenically unsaturated monomers having an acetoacetyl group as a cross-linking functional group are those that stably generate insoluble microgels in the vinyl copolymer (A) and impart matte performance. It is. Illustrative examples include acetoacetoxyethyl acrylate, acetoacetoxyethyl methacrylate, and the like. After the electrodeposition coating composition of the present invention is dispersed in water by the method described later, a microgel is formed in the dispersed particles to reduce gloss. . In that case, since the formation of microgel is promoted by using formaldehyde together, it is preferable to use formaldehyde together.

  Furthermore, for other α, β-ethylenically unsaturated monomers, alkyl esters of acrylic acid or methacrylic acid, or other vinyl monomers and amide monomers can be used. Specific examples of the compound include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl. Acrylic acid such as methacrylate, t-butyl acrylate, t-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, heptyl acrylate, heptyl methacrylate or the like Methacrylic acid Alkyl monomers, styrene, α-methylstyrene, vinyl toluene, vinyl acetate, acrylonitrile, methacrylonitrile, and other vinyl monomers, acrylamide, methacrylamide, methylol acrylamide, methylol methacrylamide, methoxymethyl acrylamide, n-butoxymethyl acrylamide, Examples thereof include amide monomers such as diacetone acrylamide and diacetone methacrylamide, ethylene glycol diacrylate, ethylene glycol dimetallate, trimethylolpropane triacrylate, and trimethylolpropane trimethacrylate. These may be used alone or in combination of two or more.

  The Tg (glass transition temperature) of the vinyl copolymer (A) is 0 to 50 ° C. When the Tg is lower than 0 ° C., the physical properties, particularly the hardness, of the dried coating film are reduced, and the vinyl copolymer (B ) And the stability of the electrodeposition paint is reduced. Moreover, when Tg is high, it becomes difficult to obtain an electrodeposition coating film. About the concrete numerical value of Tg of a copolymer, it calculates with the formula of the following Fox. Moreover, the preferable weight average molecular weights of a vinyl copolymer (A) are 10,000-100,000, More preferably, it is 20,000-70,000. When the weight average molecular weight is 10,000 or less, the coating film durability is hardly obtained. When the weight average molecular weight is 100,000 or more, the water dispersibility is lowered, and the handleability of the paint tends to be poor.

  The vinyl copolymer (A) as described above can be obtained by polymerizing each monomer by a known method such as solution polymerization, non-aqueous dispersion polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, etc. Solution polymerization is preferred, and the reaction temperature is usually 40 to 170 ° C.

  Reaction solvents include n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, t-butyl alcohol, propyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono It is preferable to use a hydrophilic solvent such as butyl ether. Moreover, as a polymerization initiator, well-known things, such as an organic peroxide, an azo compound, ammonium persulfate, potassium persulfate, can be used.

[(B) Vinyl copolymer]
The vinyl copolymer (B) used in the present invention is used together with the vinyl copolymer (A) to increase the hardness of the resulting electrodeposition coating film and improve the scratch resistance. The content of α, β-ethylenically unsaturated monomers having a Tg (glass transition temperature) of the homopolymer of 60 ° C. or more and 170 ° C. or less is 40 to 90% by weight, the hydroxyl group-containing α, β-ethylenically unsaturated A vinyl copolymer having a saturated monomer content of 5 to 40% by weight and (g) other α, β-ethylenically unsaturated monomer as the remaining part by weight. The copolymer (B) preferably contains a carboxyl group in order to obtain a stable resin liquid dispersion, and the acid value thereof is preferably from 5 to 100 KOHmg / g. In this case, it is preferable to copolymerize the monomer exemplified in the section of the α, β-ethylenically unsaturated carboxylic acid monomer of the vinyl copolymer (A). However, even when the vinyl copolymer (B) does not have an acid value, the performance of the obtained coating film is not adversely affected.

  The α, β-ethylenically unsaturated monomer having a homopolymer Tg of 60 ° C. or more and 170 ° C. or less includes styrene (100 ° C.), α-methylstyrene (168 ° C.), vinyltoluene (varies depending on the isomer). 93-136 ° C), methyl methacrylate (105 ° C), ethyl methacrylate (65 ° C), isopropyl methacrylate (81 ° C), t-butyl methacrylate (118 ° C), cyclohexyl methacrylate (83 ° C), acrylonitrile (100 ° C), acrylic Acid (106 ° C.), methacrylic acid (130 ° C.), acrylamide (165 ° C.) and the like can be used, but are not limited thereto. Moreover, there is no problem even if these are used alone or in combination. The content of these monomers in the vinyl copolymer (B) is preferably 40 to 90% by weight. If the content is less than 40% by weight, a sufficient effect of improving the hardness of the coating film cannot be obtained. If the content exceeds 90% by weight, the compatibility with the vinyl copolymer (A) decreases, Stability is reduced.

  The α, β-ethylenically unsaturated monomer (e) having a Tg of 60 ° C. or higher and 170 ° C. or lower is included in the vinyl copolymer (A) (d) other α, β-ethylene. Although what is used in common with the unsaturated monomer is included, the content of the vinyl copolymer (B) of the α, β-ethylenically unsaturated monomer of (e) is 40 to 90% by weight. The vinyl copolymer (B) obtained has a different effect from the vinyl copolymer (A).

  As the hydroxyl group-containing α, β-ethylenically unsaturated monomer, a hydroxyl group-containing α, β-ethylenically unsaturated monomer that can be used in the vinyl copolymer (A) can be used. The content in the combined body (B) is preferably 5 to 40% by weight. If it is less than 5% by weight, sufficient hardness improvement cannot be obtained upon curing by baking, and if it exceeds 40% by weight, the coating film becomes brittle and water resistance and the like are lowered.

  Further, as other α, β-ethylenically unsaturated monomers, the following monomers can be exemplified. Specific examples include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, cyclohexyl acrylate, lauryl acrylate, lauryl. Methacrylate, stearyl acrylate, stearyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, heptyl acrylate, alkyl esters of methacrylic acid such as heptyl methacrylate, other monomers such as vinyl acetate, n-butoxymethyl acrylamide, In addition, ethylene glycol diacrylate and neopentyl glycol diac Rate, trimethylolpropane triacrylate, although polyfunctional monomers such as pentaerythritol tetraacrylate are not limited to. Moreover, these can be used 1 type or in mixture of 2 or more types.

  The weight average molecular weight of the vinyl copolymer (B) is preferably 5,000 to 50,000, and is preferably smaller than the weight average molecular weight of the vinyl copolymer (A). The Tg of the vinyl copolymer (B) is preferably 50 to 120 ° C., and is preferably higher than the Tg of the vinyl copolymer (A). The vinyl copolymer (B) has the monomer composition, weight average molecular weight, and Tg as described above, and is preferably produced so as to have an acid value. ) It can be obtained by the same production method.

  The use ratio of the vinyl copolymer (A) and the vinyl copolymer (B) is preferably (A) / (B) = 100/1 to 100/40 (solid content weight ratio), more preferably 100/1. To 100/30, more preferably 100/3 to 100/25.

[(C) Crosslinking agent]
Examples of the crosslinking agent (C) used in the present invention include conventionally known melamine resins, benzoguanamine resins, urea resins and the like. Among them, preferred are those in which at least part of the methylol group is lower. An alkyl etherified methylol melamine resin alkoxylated with an alcohol, and as the lower alcohol, one or more of methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol and the like can be used. Moreover, even if it is 1 type of melamine resin and 2 or more types of melamine resins are combined, there is no problem.

  Examples of the alkyl etherified methylol melamine resin include Cymel 266, 232, 235, 238, 236 manufactured by Mitsui Cytec Co., Ltd., My Coat 506, 508, 548, M-66B, and Nicarak MX manufactured by Sanwa Chemical Co., Ltd. -40, MX-45, etc., but are not limited to these.

  Crosslinking agents other than amino resins include blocked isocyanates, which are a reaction product of a compound having two or more isocyanate groups in one molecule and a compound having active hydrogen capable of reacting with the isocyanate group, or one in one molecule. And compounds having one or more uretdione groups.

  Such compounds having two or more isocyanate groups in one molecule are tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, hydrogenated tolylene diisocyanate, hydrogen. Diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, etc., and isocyanurate type trimers, burette type trimers, or polyols such as triazine tricarbamic acid trialkyl ester, trimethylolpropane, glycerin and the like and the above diisocyanates. In general, a compound called an adduct is a reaction product.

  Among them, more preferable compounds when the weather resistance is emphasized include isophorone diisocyanate, hexamethylene diisocyanate, dimer acid diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, and these isocyanates. Examples thereof include a nurate trimer, a burette trimer, or a reaction product of one triazine tricarbamic acid trialkyl ester, one trimethylolpropane or one glycerin molecule and the above three diisocyanate molecules.

  Examples of the compound having active hydrogen that can react with the isocyanate group include alcohols having 1 to 4 carbon atoms, ε-caprolactam, methyl ethyl ketoxime, alkyl acetoacetate, dialkyl malonate, furfuryl alcohol, phenol, butyl cellosolve, and the like. Can be mentioned.

  The reaction product of the compound having two or more isocyanate groups in one molecule and the compound having active hydrogen capable of reacting with the isocyanate group has an equivalent ratio of isocyanate group to active hydrogen group of about 1/1. Usually, it is obtained by reacting at 50 to 150 ° C. If necessary, an organic solvent or a reaction catalyst (mainly an organic tin compound) may be used. Moreover, the compound which has a uretdione group is a compound obtained by the uretdione reaction of the isocyanate groups of the said isocyanate compound.

  A preferable range of the amount of the crosslinking agent used is 10 to 100 parts by weight with respect to a total of 100 parts by weight of the vinyl copolymer (A) and the vinyl copolymer (B). If it is less than this range, the coating film is insufficiently crosslinked, resulting in a decrease in hardness, mechanical properties, solvent resistance, chemical resistance, and the like. On the other hand, when the amount exceeds 100 parts by weight, the affinity with the vinyl copolymers (A) and (B) becomes insufficient, resulting in poor stability of the aqueous dispersion, non-uniform dispersion particle size, and after electrodeposition. Problems such as poor washability, water repellency, gloss unevenness of the coating film, and whitening occur, and an excessive crosslinking agent does not contribute to crosslinking and remains as a plasticizer. A more preferable range of the amount of the crosslinking agent is 20 to 90 parts by weight with respect to 100 parts by weight as a total of the vinyl copolymer (A) and the vinyl copolymer (B).

A curing catalyst can be added to the electrodeposition coating composition of the present invention in order to further improve the curability during baking of the coating film, and sulfonic acid compounds and tin compounds are useful as the curing catalyst.
Examples of the sulfonic acid compound include, but are not limited to, p-toluenesulfonic acid, cumenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, and amine salts thereof. .
Examples of the tin compound include, but are not limited to, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin oxide, and tetrabutyldiacetoxy distanoxane.

  The electrodeposition paint of the present invention is prepared by stirring and mixing the above-mentioned vinyl copolymer (A), vinyl copolymer (B) and (C) crosslinking agent usually at 40 to 100 ° C., and if necessary, a curing catalyst. Add deionized water containing a basic substance for neutralization and stir and mix at a temperature of 20 to 80 ° C. to obtain an emulsified dispersion, and then react the cross-linked functional groups in the vinyl copolymer (A). Thus, it is a general method to form a microgel. Further, it is heated as necessary, or diluted with deionized water or deionized water partially containing a hydrophilic solvent, and used for electrodeposition coating.

  The aforementioned basic substance is a compound for neutralizing at least a part of the carboxyl group in the vinyl copolymer to be dispersed in water, and is, for example, an organic amine or an inorganic base. Examples of such basic substances include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, monobutylamine, dibutylamine, tributylamine and other alkylamines, diethanolamine, diisopropanol Alkanol amines such as amine, triethanolamine, dimethylethanolamine, diethylethanolamine, alkylenediamines such as ethylenediamine, propylenediamine, diethylenetriamine, triethylenetetramine, ammonia, ethyleneimine, pyrrolidine, piperidine, piperazine, morpholine, sodium hydroxide, A potassium hydroxide etc. are mentioned. The neutralization rate with such a basic substance is appropriately 20 to 120%, but particularly preferably 40 to 100%, since water dispersibility is good and gloss unevenness does not occur.

  In addition, it is also possible to further improve the weather resistance by using an ultraviolet absorbing group-containing compound or a hindered amine group-containing compound. By using an ultraviolet absorbing group or a hindered amine group-containing monomer, a vinyl copolymer (A ) And / or vinyl copolymerization (B). Furthermore, additives such as antifoaming agents, leveling agents, and surfactants may be added as necessary. The technique of the present invention can also be applied to a colored type electrodeposition paint in combination with a pigment. Further, for example, a xylene resin, a polyester resin, a urethane resin, or the like can be used in combination according to required performance, workability, cost, and the like. In this case, it is used in the same manner as the crosslinking agent.

The object to which the electrodeposition coating method of the present invention is applied is mainly aluminum or an aluminum alloy, but it can be coated if it has conductivity, and the obtained coating film cannot be obtained by the prior art. In addition to achieving high scratch resistance and coating film hardness that are not possible, it also has excellent weather resistance, mechanical properties, solvent resistance, chemical resistance, workability, and the like.
Abrasion resistance was evaluated by measuring the pencil hardness and by applying a load on the surface of the HEIDON-18L continuous load type scratch strength tester manufactured by Shinto Kagaku Co., Ltd.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these. In addition, unless otherwise indicated, the compounding quantity in a table | surface represents a weight part and weight%.

[Production of vinyl copolymer (A)]
Production Example 1 (Production of resin liquid A1)
A reactor having a stirring device, a thermometer, a monomer dropping device, and a reflux cooling device is prepared. In accordance with the formulation shown in Table 1, (1) and (2) were charged into a reactor, raised to reflux temperature with stirring, and (3) to (10) were mixed uniformly in advance and then added dropwise over 3 hours. . The temperature was maintained at the reflux temperature. (1.5) was added 1.5 hours after the completion of dropping, and the reaction was further continued at the same temperature for 1.5 hours to obtain a transparent and viscous resin liquid A1. The acid value (KOH mg / g solid content), hydroxyl value (KOH mg / g solid content), Tg (° C.), and weight average molecular weight are also shown in Table 1.

Raw materials used AAEM: Acetoacetoxyethyl methacrylate

[Production of vinyl copolymer (B)]
Production Examples 2 to 4 (Resin Liquids B1 to B3) For Example Production Example 5 (Resin Liquid B4) For Comparative Example Similar to the production example of the vinyl copolymer (A), a stirrer, a thermometer, a monomer dropping device, A reactor having a reflux cooling device is prepared. According to the composition shown in Tables 2 and 3, (1) was charged into a reactor, and the temperature was raised to the reflux temperature with stirring. After mixing (2) to (12) uniformly in advance, the solution was added dropwise over 3 hours. The temperature was maintained at the reflux temperature. (1.5) is added 1.5 hours after the end of dropping, and the reaction is further continued for 1.5 hours at the same temperature, and transparent and viscous resin liquids B1 to B3 (for Examples) and resin liquid B4 (comparison) For example). Tables 2 and 3 show the monomer amounts (%), hydroxyl group-containing monomer amounts (%), weight average molecular weights, and acid values (KOH mg / g solid content) of Tg 60 ° C. or higher and 170 ° C. or lower.

[Production of dispersion resin liquids C1 and C2]
A reactor having a stirring device, a thermometer, a deionized water dropping device, and a reflux cooling device is prepared. According to the formulation shown in Table 4, (1) to (5) were charged into a reactor and stirred and mixed at 60 ° C. for 1 hour. To this was gradually added the mixture of (6) and (7) to obtain an emulsion. Further, (8) was added, and the mixture was kept at 50 ° C. for 4 hours to carry out a microgelation reaction. Finally, (9) was added to each to prepare a dispersion resin solution for Examples.

Raw material used Cymel 236: Nippon Cytec Industries, Ltd. mixed ether type melamine resin 100% solid content

[Production of Dispersed Resin Liquid D1]
Dispersion resin liquid D1 was prepared in the same manner as dispersion resin liquids C1 and C2. (6) was added and incubated at 50 ° C. for 4 hours to carry out a microgelation reaction.

Raw material used Cymel 236: Nippon Cytec Industries, Ltd. mixed ether type melamine resin 100% solid content

[Manufacture of electrodeposition paint]
After adding deionized water to the dispersion resin liquids C1 and C2 and D1 to adjust the solid content to 10%, triethylamine is added to adjust the pH to 8.0, and the corresponding electrodeposition paint E1 and E2 (for Examples) and F1 (for Comparative Examples) were obtained.

[Electrodeposition coating and coating film performance evaluation]
(Example 1 and Example 2 and Comparative Example 1)
The electrodeposition paints obtained above (Examples 1 and 2 use the electrodeposition paints E1 and E2, and Comparative Example 1 use the electrodeposition paint F1) are placed in a vinyl chloride bath, and the cathode is a SUS304 steel plate. The 6063S aluminum alloy plate was alumite-treated (alumite film thickness = 9 μm), and further electrolytically colored to black, and then electrodeposited with an aluminum material washed with hot water as a positive electrode (coating material). . The specific conditions for electrodeposition coating were as follows: a bath temperature of 22 ° C. and a coating voltage of 130 V; energization was carried out so that the coating thickness was 10 μm; washing was performed after the electrodeposition; and then baking was performed at 185 ° C. for 30 minutes. The performance of the obtained coating film was evaluated, and the results are shown in Tables 6 and 7.

The evaluation method of emulsification property, bath solution stability and coating film performance is as follows.
(1) Emulsification: The dispersion resin liquid is filtered and determined by the presence or absence of a filtration residue.
○: No filtration residue
×: Many filtration residues (2) Stability of bath solution: After coating evaluation, the bath solution is adjusted to 30 ° C. and held for 4 weeks under stirring, and then coating evaluation is performed again. Compare the difference in gloss and appearance of the painted plate between the initial and time.
○: Almost no difference in gloss and appearance
X: Difference in gloss and appearance (3) Gloss value: Measure 60 ° specular reflectance [%] with a gloss meter.
(4) Pencil hardness: JIS-K-5600 tear determination.
(5) Cross-cut adhesion: JIS-K-5600 Adhesive state when the cellophane tape is quickly peeled off after making 100 cross-cuts with a cutter knife on the coating film and pasting the cellophane tape on it. Observe. The description in the performance evaluation table means the following.
100: No peeling (100/100)
0: All peeled off (0/100)
(6) Alkali resistance: The coated surface state was observed after immersion in a 1% aqueous sodium hydroxide solution at 20 ° C. for 120 hours.
(7) Acid resistance: After immersing in a 5% sulfuric acid aqueous solution at 20 ° C. for 120 hours, the coated surface state was observed. (8) Scratch resistance: Visually evaluated the degree of scratching after rubbing 50 reciprocating coated plates with a stroke of 5 cm by applying a load of 200 g / cm ^{2 to} the cardboard paper.
○: A slight scar is visible.
X: It looks like a surface with deep scars or reduced gloss.
(9) Scratchability test: Measured and evaluated by using a HEIDON-18L continuous weight type scratch strength tester manufactured by Shinto Kagaku Co., Ltd., and measuring the load at the start of scratching and reaching the wound substrate.

  In the case of acrylic matte electrodeposition coating on aluminum building materials, etc., a vinyl copolymer (A) having a acetoacetyl group as a carboxyl group, a hydroxyl group and a cross-linking functional group, and a homopolymer having a Tg of 60 ° C. or more and 170 ° C. or less. By using a matte electrodeposition paint comprising a vinyl copolymer (B) comprising a monomer and a hydroxyl group-containing monomer and other monomers and a curing agent (C), the scratch resistance of the coating film is It can improve without impairing the performance of other coating films.

Claims (2)

(A) (a) α, β-ethylenically unsaturated carboxylic acid monomer, (b) hydroxyl group-containing α, β-ethylenically unsaturated monomer, (c) α having an acetoacetyl group as a crosslinking functional group , Β-ethylenically unsaturated monomer, and (d) other α, β-ethylenically unsaturated monomers Tg is 0-50 ° C., acid value is 10-150 KOHmg / g, hydroxyl value Is a vinyl copolymer of 20 to 200 KOHmg / g, (B) (e) 40 to 90% by weight of an α, β-ethylenically unsaturated monomer having a Tg of 60 ° C. or more and 170 ° C. or less, f) 5 to 40% by weight of a hydroxyl group-containing α, β-ethylenically unsaturated monomer, and (g) a weight average molecular weight obtained by copolymerizing other α, β-ethylenically unsaturated monomers is 5,000 to Electrodeposition coating set containing 50,000 vinyl copolymer and (C) crosslinker An anionic matte electrodeposition coating composition, wherein the weight ratio of vinyl copolymer (A) / (B) is 100/1 to 100/40. In vinyl copolymer (B), anionic matte electrodeposition coating composition of claim 1 Symbol placement acid value is 5~100KOHmg / g.