JP2000186235A - Anionic thermosetting electropaint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anionic thermosetting electropaint yielding a high coating finish. SOLUTION: In an anionic thermosetting electropaint containing a resin containing a hydroxyl group and a carboxyl group, a crosslinking agent, a basic neutralizing agent and water as essential components, the amount of the basic neutralizing agent mixed is within the range of from 0.1 to 2.0 neutralization equivalent. Here, the neutralizing agent contains 50 wt.% or more alkanol amine having a boiling point within the range of from 130 to 180 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel anionic thermosetting electrodeposition paint.

[0002]

2. Description of the Related Art At present, an anodized thermosetting electrodeposition paint having a good finish is applied to an object to be coated such as an anodized aluminum sash.

[0003] As a method of applying the electrodeposition paint, an object to be coated is electrodeposited in an electrodeposition paint bath, and then, when the object is lifted out of the bath, an extra paint (coating liquid) )
There is known an electrodeposition coating method in which the coating liquid is removed by setting (non-rinsing) or washing with water (such as tap water or RO permeated water) (rinsing) and then baking.

[0004] However, in the non-rinse type electrodeposition coating method described above, the coating liquid adhering to the deposited coating film becomes streak (stripe) during setting or baking, and flows down to deteriorate the appearance of the coating film. There was a point. Also, in the rinse-type electrodeposition coating method, the washing water adhering to the deposited coating film is dried in an uneven manner, resulting in a streak (stripe) during setting or baking, or an incongruity with the dried portion. There is a problem that the appearance of the coating film (dry unevenness, uneven gloss, smoothness, etc.) is deteriorated because the gloss of the dried portion is changed.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to develop an anionic thermosetting electrodeposition coating composition which improves the finish appearance of a conventional anionic thermosetting electrodeposition coating composition.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the conventional anionic thermosetting electrodeposition paint has been specified as a neutralizing agent. It has been found that a coating film having an excellent finished appearance can be provided by using a waving agent, and the present invention has been completed.

That is, the present invention relates to an anionic thermosetting type electrodeposition coating composition containing a hydroxyl group and a carboxyl group-containing resin, a crosslinking agent, a basic neutralizing agent, and water as essential components. Is a neutralization equivalent in the range of 0.1 to 2.0, and the neutralizing agent has a boiling point of 130 in the neutralizing agent.
The present invention relates to an anionic thermosetting electrodeposition coating material containing 50% by weight or more of an alkanolamine in a temperature range of 180 to 180 ° C.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The basic neutralizing agent referred to in the present invention is used when the compounding amount of the basic neutralizing agent is in the range of 0.1 to 2.0 in terms of neutralization equivalent to the hydroxyl group- and carboxyl group-containing resin. So,
And the neutralizing agent has a boiling point of 130 to 180 in the neutralizing agent.
Alkanolamine in the range of 155 ° C to 170 ° C, preferably at least 50% by weight. The neutralization equivalent is 0.
If it is less than 1, the resin will be poorly dispersed in water and the storage stability of the paint will be poor. On the other hand, if it exceeds 2.0, high coating voltage, discoloration of the coating film, coating film performance, etc. will decrease. Neutralizer boiling point 13
If the temperature is lower than 0 ° C., the film becomes easy to dry during setting, and the coating appearance such as uneven drying resistance and anti-coating solution (Yolimula (stripe)) deteriorates. . The above-mentioned alkanolamine having a boiling point is contained in the neutralizing agent used in an amount of 50% by weight or more. If the amount is less than 50% by weight, the above-mentioned effects cannot be obtained.

Further, as the basic neutralizing agent, more preferably, the base strength (PKa, where PKa is the ionization constant K of the base)
a) is in the range of 9.5 to 10.7, preferably 9.8 to 10.5, and the solubility parameter (SP) is 8.0 to 11.5, preferably 9.0. ~ 1
A range of 1.0 is preferred. If the basic strength is less than 9.5, the amount of the coating increases, and the coating performance such as acid resistance deteriorates. Solubility), stripe resistance, smoothness, gloss and the like are deteriorated. When the solubility parameter is less than 8.0, unevenness in dryness, stripe resistance, gloss and the like are reduced. On the other hand, when the solubility parameter is more than 11.0, re-dissolution resistance, stripe resistance, smoothness, gloss and the like of a coating film are reduced. Is not preferred because it becomes worse.

The preferred basic neutralizing agents described above include:
Particularly, 2-dimethylamino-2-methyl-1-propanol and 2-amino-2-methyl-1-propanol are preferred, and 2-dimethylamino-2-methyl-1-propanol is more preferred.

Other basic neutralizers which can be used in combination with the above-mentioned preferred ones include, for example, ammonia; ethylamine, propylamine, butylamine, benzylamine, monoethanolamine, neopentanolamine, 2-aminopropanol Primary amines such as, 3-aminopropanol; diethylamine, diethanolamine, di-n- or di-iso-propanolamine, N-methylethanolamine, N-
Secondary monoamines such as ethylethanolamine; tertiary monoamines such as dimethylethanolamine, trimethylamine, triethylamine, triisopropylamine, methyldiethanolamine, dimethylaminoethanol; diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine And the like.

The anionic thermosetting electrodeposition coating composition referred to in the present invention is very generally known, and includes an aqueous base resin having a skeleton containing a carboxyl group and a hydroxyl group, an amino resin, and a block polyisocyanate. A cross-linking agent such as a compound is obtained by neutralizing a vehicle component with the above-mentioned basic neutralizing agent and then dispersing in water.

The above-mentioned aqueous base resin includes, for example,
Vinyl copolymer, polyester resin, alkyd resin,
Fluororesins, silicone resins and the like can be mentioned. These resins can be used alone or in combination of two or more. Among these, it is preferable to use the following vinyl copolymers.

As the vinyl copolymer, a vinyl copolymer obtained by subjecting a hydroxyl group-containing vinyl monomer, an ethylenically unsaturated carboxylic acid and, if necessary, another unsaturated monomer to a radical copolymerization reaction is used. No.

The following are examples of these monomer components.

(1) Hydroxyl-containing vinyl monomers: for example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, (poly) ethylene glycol mono (Meth) acrylate, (poly) propylene glyco-
Mono (meth) acrylate, hydroxybutyl vinyl ether, (meth) allyl alcohol, and the above-mentioned hydroxyl-containing vinyl monomers and β-propiolactone;
Dimethyl propiolactone, butyrolactone, γ-valerolactone, γ-caprolactone, γ-caprylolactone, γ-laurylolactone, ε-caprolactone, δ-
The trade name of a reaction product with a lactone compound such as caprolactone is Praxel FM1 (manufactured by Daicel Chemical Industries, Ltd.
Brand name, caprolactone-modified (meth) acrylic acid hydroxyesters), Placcel FM2 (same as left), Placcel FM3 (same as left), Placcel FA-1 (same as left), Placcel FA2 (same as left), Placcel FA3 (same as left)
etc.

(2) Ethylenically unsaturated carboxylic acids: for example, (meth) acrylic acid, maleic acid, Placcel F
M1A (hereinafter, manufactured by Daicel Chemical Industries, caprolactone-modified carboxyl group-containing (meth) acrylic monomer, trade name), Praxel FM4A, Praxel FM10A and the like.

(3) Other unsaturated monomers: for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate , (meth) acrylate, octyl (meth) acrylate, lauryl (meth) alkyl or cycloalkyl esters of C ₁ -C ₁₈ (meth) acrylic acid such as cyclohexyl acrylate, aromatic such as styrene vinyl monomers - s , (Meta)
(Meth) acrylamides such as acrylamide, N-butoxymethyl (meth) acrylamide, N-methylol (meth) acrylamide and derivatives thereof, and (meth)
Acrylonitrile compounds, etc., alkoxysilyl groups such as γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, vinyltrimethoxysilane Containing vinyl monomers.

In terms of the proportion of these monomers, the above hydroxyl-containing monomers have a copolymer having a hydroxyl value of about 3
It may be blended so as to fall within the range of 0 to 300 mgKOH / g, but the amount of the hydroxyl group-containing monomer is about 3 to 40% by weight, preferably about 5 to 5% in terms of the total amount of the above monomers.
It is in the range of 30% by weight.

The above ethylenically unsaturated carboxylic acid may be blended so that the acid value of the copolymer falls within the range of about 10 to 200 mg KOH / g, and is based on the total amount of the above monomers. And the ethylenically unsaturated carboxylic acid ranges from about 3 to 30% by weight, preferably about 4 to 20% by weight.

As other unsaturated monomers, it is preferable to use C ₁ -C ₁₈ alkyl or cycloalkyl esters of (meth) acrylic acid and aromatic vinyl monomers such as styrene. The amount of the monomers is about 37 to 95 based on the total amount of the monomers.
%, Preferably in the range of about 60-91% by weight.

[0022] As a method of causing a radical copolymerization reaction,
Conventionally known solution polymerization methods can be used.

As the cross-linking agent, for example, methanol or ethanol, propanol, butanol, octyl alcohol,
Those modified with one or more monohydric alcohols such as 2-ethylhexyl alcohol can be used. It is preferable that the melamine resin has a mononuclear to polynuclear (about 2 to 5) nucleus content of 50% by weight or more. Also,
The melamine resin may contain other functional groups such as an imino group and a methylol group. As the matte electrodeposition paint, C ₃ or more monohydric alcohols, in particular C ₄ -C ₁₈ monohydric alcohol modified ether group triazine ring 1 nucleus per average of about 2.0 or more, particularly 2 It is preferable to contain from 0.0 to 5.0.

Examples of the blocked polyisocyanate crosslinking agent include lactones such as ε-caprolactone, methanol, ethanol, propanol, butanol, and aliphatic or alicyclic polyisocyanates such as isophorone diisocyanate and hexamethylene diisocyanate. Those blocked with alcohols such as pentanol and oximes such as methyl ethyl ketoxime and methyl isobutyl ketoxime can be used.

In the paint of the present invention, the mixing ratio of the aqueous base resin and the cross-linking agent is 40 to 85% by weight, preferably 50 to 80% by weight, based on the total solid content of both.
% By weight, and the crosslinker ranges from 15 to 60% by weight, preferably from 20 to 50% by weight. If the amount of the aqueous base resin is less than 40% by weight, and if the amount of the crosslinking agent exceeds 60% by weight, the coating properties such as weather resistance and workability deteriorate, while the amount of the aqueous base resin is 85% by weight. If the amount exceeds the above value and the amount of the crosslinking agent is less than 15% by weight, the coating properties such as weather resistance, abrasion resistance and workability deteriorate, which is not preferable.

The paint of the present invention may contain, if necessary, an organic solvent,
Pigments, dyes, fluidity modifiers and the like can be added.

The paint of the present invention may be any type of paint such as a building bath paint, a replenishing paint and a line paint.

The paint of the present invention is used as a glossy or matte paint, and a coating film can be formed by the following non-rinse or rinse coating method. When a coating film is formed by non-rinsing or rinsing using a glossy coating material, there is no coating defect such as uneven drying and dripping streaks, and a coating film having excellent smoothness can be formed.

When a paint film is formed by rinsing using a matte paint, a paint film having excellent smoothness can be formed without the same coating defects as described above such as dry unevenness and dripping streaks.

The paint of the present invention is preferably applied particularly to the field of aluminum building materials using a colored or uncolored anodized aluminum material.

The paint of the present invention is obtained by using the anionic thermosetting electrodeposition paint obtained above as an electrodeposition paint bath, immersing the aluminum material in the bath, and then obtaining a dry film thickness of about 5 to 30 microns. Anion electrodeposition coating is performed so as not to perform water washing (non-rinsing) or to perform water washing (rinsing), then set at room temperature, and then baked (for example, about 160
To 200 ° C. for about 20 to 40 minutes) to form a coating film.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to embodiments. The invention is not limited to the embodiments provided.

Production Example of Acrylic Copolymer (a) 70 g of isopropyl alcohol was charged into a reaction vessel and kept at 80 ° C., and 10 g of styrene, 31 g of methyl methacrylate, 10 g of n-butyl acrylate, 30 g of ethyl acrylate, 2-hydroxyethyl acrylate
A mixture of 12 g of acrylic acid, 7 g of acrylic acid, and 2 g of azobisdimethylvaleronitrile was added dropwise over 3 hours, and then 1 g of azobisdimethylvaleronitrile was added.
For 1 hour to produce a reactive varnish (a). The copolymer had a weight average molecular weight of about 20,000 and an acid value of 55 m.
gKOH / g and a hydroxyl value of 58 mgKOH / g.
This copolymer (a) is used for a glossy electrodeposition paint.

Production Example of Acrylic Copolymer (b) 70 g of isopropyl alcohol was charged into a reaction vessel and kept at 80 ° C., and 10 g of styrene, 24 g of methyl methacrylate, γ-methacryloxypropyltrimethoxy were added. 7 g of silane, 10 g of n-butyl acrylate, 30 g of ethyl acrylate, 2-hydroxyethyl acrylate
A mixture of 12 g of acrylic acid, 7 g of acrylic acid, and 2 g of azobisdimethylvaleronitrile was added dropwise over 3 hours, and then 1 g of azobisdimethylvaleronitrile was added.
For 1 hour to produce a reactive varnish (b). The copolymer has a weight average molecular weight of about 25,000 and an acid value of 5
5 mgKOH / g and a hydroxyl value of 58 mgKOH / g. This copolymer (b) is used for a matte electrodeposition paint.

Example 1 0.4 kg of 2-dimethylamino-2-methyl-1-propanol (boiling point) based on the carboxyl group of the copolymer (a) was added to 7 kg (solid content) of the copolymer (a). 16
After mixing 0 ° C., PKa 10.20, SP 9.05, and the above-mentioned technical literature data manufactured by Angus Chemical Co., Ltd., mix and disperse the mixture.
After mixing and dispersing 3 kg (trade name, butoxylated melamine resin, manufactured by Sanwa Chemical Co., Ltd.), deionized water was gradually added dropwise while stirring, and triethylamine was further added to adjust the pH to 8.0. The glossy electrodeposition paint of Example 1 having a solid content of 10% by weight was produced. Then the paint is heated to 30 ° C
For 7 days to effect aging of the paint. The aging was manufactured on the assumption of a line paint having advanced running. By aging, volatilized water and isopropanol were added, and butyl cellosolve and diethylene glycol mono-2-ethylhexyl ether (boiling point: 272 ° C., solubility: 0.3) were added.

Example 2 In Example 1, 2-dimethylamino-2-methyl-
1-propanol was converted to 2-amino-2-methyl-1-propanol (boiling point 165 ° C., PKa 9.82, SP10.
91, a clear glossy electrodeposition paint of Example 2 was produced in the same manner as in Example 1 except that the same amount was used instead of the above-mentioned technical literature data (manufactured by Angus Chemical Company).

Example 3 In Example 1, the copolymer (a) was replaced with the copolymer (b)
And Nicaraq MX-600 to Nicaraq MX-4
30 (manufactured by Sanwa Chemical Co., Ltd., trade name, melamine core 1)
About 3 methyl groups, about 3 butyl groups, and about 1% of the nucleus are used in the same amount as in Example 1, except that the same amounts were used. A clear paint was obtained.

Example 4 In Example 3, 2-dimethylamino-2-methyl-
A clear matte electrodeposition coating material of Example 4 was produced in the same manner as in Example 3, except that 1-propanol was replaced with the same amount of 2-amino-2-methyl-1-propanol.

Comparative Example 1 In Example 1, 2-dimethylamino-2-methyl-
1-propanol is converted to triethylamine (boiling point 89 ° C, P
A clear glossy electrodeposition paint of Comparative Example 1 was produced in the same manner as in Example 1 except that Ka 10.78, SP7.46, and technical literature data (manufactured by Union Carbide Co., Ltd.) were replaced by the same amount.

Comparative Example 2 In Example 1, 2-dimethylamino-2-methyl-
Same as Example 1 except that 1-propanol was replaced with the same amount of N, N-dimethylethanolamine (boiling point 135 ° C., PKa 9.31, SP 9.78, technical literature data from Union Carbide). A clear glossy electrodeposition paint of Comparative Example 2 was produced.

Comparative Example 3 In Example 3, 2-dimethylamino-2-methyl-
1-propanol is converted to triethylamine (boiling point 89 ° C, P
A clear matte electrodeposition paint of Comparative Example 3 was produced in the same manner as in Example 3 except that Ka 10.78, SP7.46, and the above-mentioned technical literature data (manufactured by Union Carbide Co.) were replaced by the same amount.

Comparative Example 4 In Example 4, 2-amino-2-methyl-1-propanol was replaced with N, N-dimethylethanolamine (boiling point: 1
A clear matte electrodeposition paint of Comparative Example 1 was produced in the same manner as in Example 4 except that the same amount was replaced by 35 ° C., PKa 9.31, SP 9.78, and the above-mentioned technical literature data (manufactured by Union Carbide Co.). .

Coating method (non-rinse): The electrodeposition paints obtained in the above Examples and Comparative Examples were used as an electrodeposition bath, and an object to be coated (anodized aluminum material having a film thickness of about 10 microns (size: Is 1m long x 0.1m wide x 0.5m thick
m) was suspended vertically and subjected to anionic electrodeposition coating so that the dry film thickness was about 10 μm. Then, after the coated product was pulled out of the bath, the coating was performed at 20 ° C. in an atmosphere of 70% humidity for about 2 minutes. (Time until the coating liquid does not drip) Hanged and left. Next, baking was performed at 170 ° C. for 30 minutes to form coating films of Examples and Comparative Examples.

Coating method (rinse): Coating method I described above
After the anion electrodeposition coating is performed by the method described in the above, the coated product is taken out of the bath and washed with water at 20 ° C., and then at 170 ° C. for 30 minutes.
After baking for minutes, coating films of Examples and Comparative Examples were formed.

Table 1 shows the results of the appearance of the coated film of the glossy electrodeposition paint.

[0046]

[Table 1]

Table 2 shows the results of the appearance of the paint film of the matte electrodeposition paint.

[0048]

[Table 2]

The test evaluation of paint storage stability and coating film appearance is as follows.

Paint storage stability: The paint was placed in a test tube (height 20).
cm, capacity: 20 cc) and allowed to stand at 20 ° C. for 7 days, and then the height of the residue settled at the bottom of the container was examined. ◎ indicates that the residue is 0.5 mm or less, and ○ indicates that the residue is 0.6 to 5 mm.
ほ ぼ indicates that the residue is slightly defective when the residue is 6 to 10 mm, and X indicates that the residue is defective when the distance is 11 mm or more. Specular reflectance: Measured the 60-degree specular reflectance according to JIS K-5400. And the like) were visually evaluated. ◎: good, は: almost good, Δ: slightly poor, ×: poor Stripe resistance: The gloss change and unevenness due to stripes (striations of coating liquid) were visually examined. ◎ is good, ○ is almost good, △
Slightly poor, × indicates poor Drying unevenness: The gloss change of the dry unevenness on the coating film surface was visually examined. ◎: good, ほ ぼ: almost good, Δ: slightly poor, ×: poor Acid resistance: immersed in 5% by weight hydrochloric acid aqueous solution at 20 ° C. for 72 hours.
◎: No blistering at all, ○: Some blistering but good, Δ: blistering, ×: Significant blistering.

Influence of substrate: ○ indicates that the coating film is slightly turbid and the dice of the material is not conspicuous, and X indicates that the coating film is clear and the dice of the substrate is conspicuous.

[0052]

Since the paint of the present invention uses a specific basic neutralizing agent, it can form a coating film having excellent smoothness without coating defects such as dry unevenness and stripes. Can be.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J038 CC021 CG031 CG071 CG141 CG161 CG171 CH121 CH141 CJ031 CJ131 CL001 DA162 GA03 GA06 HA156 JB09 JB18 KA03 MA08 NA01 PA04 PC02

Claims (4)

[Claims] 1. An anionic thermosetting electrodeposition coating composition containing a hydroxyl group- and carboxyl group-containing resin, a cross-linking agent, a basic neutralizing agent, and water as essential components, wherein the compounding amount of the basic neutralizing agent is a neutralization equivalent. Characterized in that the neutralizing agent contains at least 50% by weight of an alkanolamine having a boiling point in the range of 130 to 180 ° C as the neutralizing agent. System thermosetting electrodeposition paint. 2. As a basic neutralizing agent, base strength (PK
The anionic thermosetting electrodeposition according to claim 1, wherein a) is in the range of 9.5 to 10.7 and the solubility parameter (SP) is in the range of 8.0 to 11.5. paint. 3. The method according to claim 1, wherein the basic neutralizing agent is 2-dimethylamino-
3. An anionic thermosetting type according to claim 1 or 2, which is at least one basic neutralizing agent selected from 2-methyl-1-propanol and 2-amino-2-methyl-1-propanol. Electrodeposition paint. 4. The method according to claim 1, wherein the basic neutralizing agent is 2-dimethylamino-
The anionic thermosetting electrodeposition paint according to claim 1, 2 or 3, which is 2-methyl-1-propanol.