JPH11349865A - Anode deposition type electrodeposition coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anode deposition type electrodeposition coating compsn. which is excellent in capability for hiding the minute grain of a substrate and can form an electrodeposited coating film with a bright external appearance by incorporating a flaky pigment mainly comprising mica or aluminum into a pigment compsn. SOLUTION: Pref., a flaky pigment having a length of 1-100 μm, an average flake size of 5-25 μm, and a thickness of 0.01-1.5 μm is used, and its content in the compsn. is pref. 1-50 wt.% of the coating film. The compsn. contains a binder comprising a partially amine- or ammonia-neutralized polycarboxylic acid resin and a curing agent. An acrylic polycarboxylic acid resin and a curing agent which causes a three-dimensional crosslinking reaction under heating are used in terms of weatherability, suitability for coloration, chemical resistance, etc. The compsn. is prepd. by partially neutralizing a mixture comprising the pigment, the polycarboxylic acid resin, and the curing agent with an amine or ammonia and then dispersing, together with water added, on a bead mill or by mixing and dispersing the pigment and a binder into an aq. resin dispersion prepd. by emulsion polymn. or suspension polymn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anodic deposition type electrodeposition paint for coating metal products such as aluminum and iron, which is excellent in concealing a fine shape of an underlayer and has a high-grade appearance with a brilliant appearance. The present invention relates to an anodic deposition type electrodeposition coating composition capable of forming a coating.

[0002]

2. Description of the Related Art Conventionally, various coatings have been applied for the purpose of preventing corrosion of metal products such as aluminum and iron, protecting surfaces and imparting aesthetic appearance. Among them, anodic deposition type electrodeposition coating is often performed because it has particularly excellent film thickness uniformity, high coating efficiency, suitability for unmanned coating, low pollution by low organic solvent content, excellent corrosion resistance and weather resistance etc. I have. However, recently, among these painted products, demands for new aesthetics have been increasing in fields where the aesthetics of the surface is important such as aluminum sashes and steel furniture. On the other hand, in the past, in most cases, clear coating films containing no pigment and coating films containing titanium oxide as a main pigment were inadequate, and the concealment of the fine shape of the base was insufficient.
There is a drawback that it is difficult to give a high-quality feeling as a coating film.

[0003]

DISCLOSURE OF THE INVENTION The inventors of the present invention have proposed a method of adding mica or aluminum to such an electrodeposition coating film in order to add a high-grade appearance that is excellent in concealing the fine shape of the base and has a glittering feeling. The present inventors have studied to incorporate a flaky pigment containing as a main component into a coating film, and have reached the present invention.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a water-soluble anodic deposition type electrodeposition coating composition comprising a polycarboxylic acid resin partially neutralized with amine or ammonia and a curing agent. By incorporating a flaky pigment containing aluminum as a main component, it is excellent in concealing the fine shape of the base such as dice mark of aluminum material, and the coating film formed from this is a high quality It adds an appearance. That is, the present invention is an anode deposition type electrodeposition coating composition comprising a flaky pigment containing mica or aluminum as a main component.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The flaky pigment used in the present invention has a longitudinal direction of 1 to 100 μm, especially 5 to 40 μm,
Average particle size 5-25 μm, thickness 0.01 μm-1.5 μ
m, particularly preferably in the range of 0.05 to 0.5 μm. For example, as an example of a composition mainly containing mica,
ME-100, ME-80W, SM manufactured by Nippon Koken Kogyo
E-80W and the like. Examples of the material containing aluminum as a main component include AW-600 and AW-5 manufactured by Asahi Kasei Corporation.
20B, AW-808C, AW-50F and the like. The flaky pigment is preferably blended so as to have a content of 1 to 50% by weight of the coating film. If it is less than 1% by weight,
Insufficient concealment of the fine shape of the underlayer, and it is not possible to add a brilliant high-grade appearance to the coating film. If it exceeds 50% by weight, it becomes difficult to form a continuous coating film, and furthermore, the stability of the coating material Is also unfavorable. Particularly preferred is 5 to 30% by weight.

The binder component used in the anodic deposition type electrodeposition coating composition of the present invention comprises a polycarboxylic acid resin partially neutralized with amine or ammonium and a curing agent thereof, and is disclosed in, for example, JP-A-59-170164. A transparent or colored coating composition as shown in JP-A-61-14177.
1, JP-A-06-107979, JP-A-07-2922
Matte clear coating composition such as 97
The binder component used in the generally known anodic deposition type electrodeposition coating composition used for the resin composition is used, the resin composition and the curing agent composition are not limited, but in particular, weather resistance, coloring suitability, chemical resistance From the viewpoint of the above, it is preferable to use an acrylic polycarboxylic acid resin and a curing agent capable of causing a three-dimensional cross-linking reaction with the resin by heating.

The acrylic polycarboxylic acid resin is
It can be obtained by copolymerizing an α, β ethylenically unsaturated carboxylic acid monomer, a hydroxyl group-containing α, β ethylenically unsaturated monomer and, if necessary, other α, β ethylenically unsaturated monomers.

Examples of the α, β ethylenically unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid and vinyl acetic acid. These monomers have a polycarboxylic acid resin having an acid value of 10 to 150 (preferably 30 to 80).
mgKOH / g is used. If it is less than 10, the stability of the paint is poor and precipitation is apt to occur, which is not preferable. On the other hand, if it exceeds 150, it easily dissolves in water, so that even if electrodeposition coating is performed, the deposited coating film is dissolved again in water and a uniform coating film is not formed. Further, problems such as poor alkali resistance of the coating film appear, which is not preferable.

The hydroxyl group-containing α, β ethylenically unsaturated monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
4-hydroxybutyl (meth) acrylate and the like, and modified lactones thereof, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, Examples include polypropylene glycol mono (meth) acrylate. These monomers are used so that the hydroxyl value of the polycarboxylic acid resin is 50 to 300 (preferably 50 to 200) mgKOH / g. If it is less than 50, the cross-linking reaction with the curing agent does not sufficiently occur, so that the strength, chemical resistance, solvent resistance, weather resistance and the like of the coating film are not practical and unfavorable. On the other hand, if it exceeds 300, the water resistance of the coating film is poor, which is not preferable.

Other α, β ethylenically unsaturated monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth) acrylate. A) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, 2-ethylhexyl (meth)
Alkyl esters of (meth) acrylic acid such as acrylate, acetoacetoxymethyl (meth) acrylate, acetoacetoxyethyl (meth) acrylate, (meth) acrylamido, N-methylol (meth) acrylamide, methoxymethyl (meth) acrylamide, amidates of (meth) acrylic acid such as n-butoxymethyl (meth) acrylamide, diacetone (meth) acrylamide, styrene, α-methylstyrene, vinyltoluene,
Examples thereof include vinyl monomers such as vinyl acetate and (meth) acrylonitrile, and polyfunctional monomers such as divinylbenzene, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and allyl (meth) acrylate. One or more of these can be used as needed.

The polycarboxylic acid resin of the present invention is obtained by copolymerizing the above monomers by a method such as solution polymerization, suspension polymerization, emulsion polymerization, non-aqueous dispersion polymerization and the like. Particularly, solution polymerization is preferred. At this time, an organic solvent is used as a reaction solvent if necessary. Examples of such organic solvents include alcohols such as ethanol, propanol and butanol, ether alcohols such as butoxyethanol, methoxypropanol, ethoxypropanol and butoxypropanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; and aromatic hydrocarbons such as toluene and xylene. And the like. Known polymerization initiators such as organic peroxides, azo compounds, ammonium persulfate, and potassium persulfate can be used as the polymerization initiator.

The curing agent used in the present invention generally comprises 1
When heated to 00 to 250 ° C., a curing agent for a baking-type paint is used which causes a three-dimensional crosslinking reaction with the above-mentioned polycarboxylic acid resin and cures. Among them, for example,
Particularly preferred are alkoxymethylated melamine and blocked isocyanate. Such a curing agent is preferably used in a weight ratio of 10 to 200 with respect to 100 of the above-mentioned polycarboxylic acid resin. If it is less than 10, curing is insufficient, and sufficient coating strength and coating performance cannot be obtained. If it exceeds 200, the coating becomes brittle, which is not preferable.

The amine used in the present invention is alkylamine such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monobutylamine, dibutylamine, tributylamine, etc., monoethanolamine, diethanolamine, dipropanolamine, dimethylethanolamine. And alkanolamines such as methyldiethanolamine, ethyldiethanolamine and triethanolamine. These are preferably used in a degree of neutralization of 10 to 100 mol% with respect to the carboxylic acid groups in the polycarboxylic acid resin. If it is less than 10, the dispersion state of the solid content of the paint in water is unstable, and precipitation tends to occur, which is not preferable. Also 10
If it exceeds 0, the electric conductivity of the paint becomes too high,
Since gas generated by electrolysis of water during electrodeposition coating increases, traces of this gas undesirably remain as coating film defects.

The electrodeposition coating composition of the present invention is obtained by partially neutralizing a mixture of the above scaly pigment and a polycarboxylic acid and a curing agent as a binder component with an amine or ammonium, and adding water to a predetermined concentration. After dilution, the dispersion may be prepared by a bead mill, or by emulsion polymerization or suspension polymerization, a scaly pigment and a curing agent are mixed with the polycarboxylic acid resin dispersed in water in advance, It may be prepared by dispersing with a bead mill. However, the present invention only needs to be in a state where these components are dispersed in water and does not cause any trouble in electrodeposition coating, and there is no particular limitation on the method for producing the coating composition.

In the present invention, if necessary, other organic or inorganic coloring pigments and extenders, colloidal silica and silica sol, additives such as antifoaming agents and leveling agents, and curing catalysts may be used.

[0016]

The present invention will be described below with reference to production examples and examples. The numbers represent parts by weight.

Production of Polycarboxylic Acid Resin (Preparation Example 1) (Polycarboxylic Acid Resin A-1) A reactor having a stirrer, a thermometer, a monomer dropping device, and a reflux cooling device is prepared. (1) ethylene glycol monobutyl ether 10.2 (2) isopropyl alcohol 40.7 (3) 2-ethylhexyl methacrylate 3.1 (4) n-butyl acrylate 26.8 (5) methyl methacrylate 29.4 (6) Styrene 13.5 (7) 2-hydroxyethyl acrylate 17.6 (8) γ-methacryloxypropyltrimethoxysilane 2.5 (9) Acrylic acid 7.1 (10) Azobisisobutyronitrile 1.0 ( 11) Azobisisobutyronitrile 0.5 Total 152.4

(1) and (2) were charged into a reactor, the temperature was raised to the reflux temperature with stirring, (3) to (10) were previously mixed uniformly, and then added dropwise over 3 hours. Temperature is 90 ±
Maintained at 3 ° C. 1.5 hours after completion of dropping, (11)
And further continued the reaction at 90 ± 3 ° C. for 1.5 hours,
After cooling, it was cooled. Resin solids = 65%, acid value = 5
A transparent and viscous polycarboxylic acid resin solution A-1 of 5 mgKOH / g (in terms of resin solid content) was obtained.

(Production Example 2) (Polycarboxylic acid resin A-
2) A reactor having a stirring device, a thermometer, a monomer dropping device, and a reflux cooling device was prepared. (1) ethylene glycol monobutyl ether 25.0 (2) isopropyl alcohol 50.0 (3) n-butyl acrylate 15.6 (4) methyl methacrylate 25.6 (5) styrene 30.0 (6) 2-hydroxyethyl Acrylate 20.0 (7) Acetoacetoxyethyl methacrylate 2.4 (8) Acrylic acid 6.4 (9) Azobisisobutyronitrile 1.0 (10) Azobisisobutyronitrile 0.2 Total 176.2 (1) was charged into a reactor, the temperature was raised to 90 ° C. with stirring, (2) to (9) were uniformly mixed in advance, and then added dropwise over 3 hours. The temperature at this time was maintained at 90 ± 3 ° C. 1.5 hours after the completion of the dropwise addition, (10) was added, and the reaction was further continued at 90 ± 3 ° C. for 1.5 hours. After cooling, the resin solid content was 56% and the acid value was 50 mgKOH / g (resin solid content equivalent). )), A transparent and viscous polycarboxylic acid resin liquid A-2 was obtained.

Production Example of Electrodeposition Coating Composition (Production Example 3) Electrodeposition coating composition B-1 (1) Polycarboxylic acid A-1 152.4 (2) Triethylamine 7.2 (3) Deionized water 160 0.0 (4) Nicaraq MX-40 50.0 (Melamine manufactured by Sanwa Chemical Co., Ltd.) (5) SME-80W 15.0 (Nippon Koken Kogyo Co., Ltd., scaly mica pigment) (6) Deionized water 1448. 7 Into 1833.3 (1), add (2) and (3) with stirring, stir for 1 hour until uniform, and then add (4). Then (5)
, And dispersed for the second time using glass beads. Subsequently, (6) was added, and the mixture was stirred and mixed for 30 minutes, and the solid content was 9%.
%, PH = 8.7, and liquid specific resistance = 1680 Ω · cm, to obtain an electrodeposition coating composition B-1.

(Production Example 4) Electrodeposition coating composition B-2 (1) Polycarboxylic acid A-2 176.2 (2) Triethylamine 7.2 (3) Deionized water 106.6 (4) Cymel 238 ( 50.0 (5) AW-600 21.7 (Asahi Kasei Corporation flake aluminum pigment) (6) 35% aqueous solution of formaldehyde 0.4 (7) Deionized water 1471.2 Total 1833. 3 (2), (3), and (4) were added to (1) with stirring, and the mixture was stirred for 1 hour until the mixture became uniform. Next, input (5),
Disperse using glass beads for 2 hours, add (6) and (7), stir and mix for 30 minutes, solid content = 9%, PH =
8.9, an electrodeposition coating composition B-2 having a liquid specific resistance of 1750 Ω · cm was obtained.

(Production Example 5) Electrodeposition coating composition B-3 (Example containing pigment other than scaly pigment) (1) Polycarboxylic acid A-1 152.4 (2) Triethylamine 7.2 (3) Deionized water 160.0 (4) Nikarac MX-40 (Melamine manufactured by Sanwa Chemical Co., Ltd.) 50.0 (5) Taipaque CR-97 (Titanium white pigment manufactured by Ishihara Sangyo Co., Ltd.) 15.0 (6) Deionized water 1448 .7 Total 1833.3 (2) and (3) were added to (1) with stirring, and the mixture was stirred for 1 hour until uniform, and then (4) was added. Thereafter, (5) is charged and dispersed for 2 hours using glass beads.
Subsequently, (6) was added, and the mixture was stirred and mixed for 30 minutes.
An electrodeposition coating composition B-3 having 9%, PH = 9.1, and liquid specific resistance = 1800 Ω · cm was obtained.

(Production Example 6) Electrodeposition coating composition B-4 (Example not containing flaky pigment) (1) Polycarboxylic acid A-2 176.2 (2) Triethylamine 7.2 (3) Deionization Water 160.0 (4) Cymel 238 (Melamine manufactured by Mitsui Cytec Co., Ltd.) 30.0 (5) 35% aqueous formaldehyde solution 0.4 (6) Deionized water 1297.1 Total 1670.9 (1) under stirring ( 2), (3) and (4) were added, and the mixture was stirred for 1 hour until the mixture became uniform. Next, input (5),
(6) was added, and the mixture was stirred and mixed for 30 minutes.
%, PH = 9.0, and liquid specific resistance = 1810 Ω · cm to obtain an electrodeposition coating composition B-4.

Examples 1 and 2 Comparative Examples 1 and 2 The electrodeposition coating compositions described in the Production Examples were placed in a 3 liter PVC tank, and the cathode was made of SUS304 steel plate.
Alumite treatment on 3S aluminum alloy plate (alumite film thickness =
9 μm) and subjected to electrodeposition coating using the material washed with hot water by a conventional method as an anode (object to be coated). Then at 180 ° C 3
After baking for 0 minutes, the coating film performance was evaluated.
The results are shown in Tables 1 and 2.

[0025]

[Table 1]

[0026]

[Table 2]

(Note) Evaluation method (1) Gloss: 60 ° gloss was measured with a gloss meter. (2) Glitter: Visual evaluation ○ = Yes × = No (3) Dice mark concealment: Visual evaluation ○ = Dice mark is not visible × = Dice mark is visible (4) Luxury feeling: Visual evaluation ○ = Excellent. △ = poor. X = very poor. (5) Alkali resistance: Observation of the coated surface after immersion in 48% 1% NaOH for 48 hours. (6) Acid resistance: After immersion in 5% sulfuric acid at 20 ° C for 48H, the state of the coated surface was observed.

[0028]

The coating composition of the present invention comprises an aluminum sash,
By painting metal parts such as steel furniture and home electric appliances, it is possible to impart a high-grade appearance with excellent concealment of the underlying fine shape and brilliant feeling to these surfaces.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Norihide Fujiki 6-10-73 Minamitsukaguchicho, Amagasaki City, Hyogo Prefecture Inside Shinto Paint Co., Ltd.

Claims (1)

[Claims] 1. An anodic deposition type electrodeposition coating composition comprising mica or a flaky pigment containing aluminum as a main component.