JPS6045666B2 - Leveling agent for water-based paints - Google Patents

Description

[Detailed description of the invention] The present invention relates to a leveling agent for water-based paints.

More specifically, water-based paints are added to water-based paints, especially cationic electrodeposition paints, to improve the appearance of the paint film, improve the interlayer adhesion with the topcoat paint film, and improve the dispersion stability of the water-based paint. Regarding a leveling agent for paint. recent years,
Electrodeposition paints are used in a wide range of fields because they are resource-saving and non-polluting.

In particular, the demand for cationic electrocoating paints is expected to increase in the future because the corrosion resistance of the resulting coatings is superior to that of anionic electrocoating paints. However, cationic electrodeposition paints generate more bubbles than anionic electrodeposition paints due to water electrolysis during electrodeposition, and in addition, the resins used are relatively polar, such as epoxy resins and urethane resins. Due to its molecular structure, it has the disadvantage that defects such as dents, orange skin, and repellency are likely to occur in the coating film during heat flow in the early stages of baking the coating film.

These coating film defects not only remain as unevenness in the coating film even after the topcoat is applied, but also have an adverse effect on the coating film, such as being susceptible to interposition from those areas due to variations in coating thickness. Various leveling agents are added to the electrodeposition paint for the purpose of improving these coating film defects.

As the leveling agent, silicone-based, fluorine-based, butyral resin-based, cellulose-based, vinyl resin-based, etc. are known. J Although the silicone-based and fluorine-based leveling agents are effective in improving the appearance of the paint film, they have the disadvantage that interlayer adhesion with the top coat paint film decreases.

In addition, the butyral resin leveling agent has a drawback of poor leveling effect. Furthermore, cellulose-based leveling agents have the drawback of not only lacking in the smoothness of the coating film but also having a negative effect on the interlayer adhesion with the top coat coating film during overbaking and on the dispersion stability of the electrodeposition coating material. Furthermore, various types of vinyl resin leveling agents are commercially available, and although they are all effective in improving the appearance of the paint film, on the other hand, adding them can improve the relationship between the top coat and the paint film. There was a problem that interlayer adhesion deteriorated.

In particular, when a cationic electrodeposition paint film was overbaked, the interlayer adhesion with the top coat paint film was significantly reduced. Furthermore, the above-mentioned vinyl resin leveling agents also had the disadvantage of adversely affecting the dispersion stability of cationic electrodeposition paints. By the way, after the above-mentioned cationic electrodeposition paint is applied to various products including automobile bodies, a paint such as an alkyd melamine resin paint or an acrylic melamine resin paint is often applied on the paint film.

Therefore, even if a cationic electrodeposition paint film has good anticorrosion properties, its value is halved if its adhesion to the top coat is poor. However, as mentioned above, among the known leveling agents, there is no one that simultaneously satisfies both the coating film properties of coating film appearance and interlayer adhesion.

In view of the above points, the present inventors have conducted extensive research into leveling agents for water-based paints, particularly cationic electrodeposition paints, and have discovered that a specific vinyl resin has excellent effects, and have arrived at the present invention.

That is, the present invention provides (4) dimethylaminoethyl methacrylate...1
0. ~70% by weight, (B) one or more alkyl esters of acrylic acid (the number of carbon atoms in the alkyl group is 1 to
4)...20 to 85% by weight, (C) one or more α,β-monoethylene. N-alkoxymethylated monomer of unsaturated carboxylic acid amide and/or N-
Methylolated monomer...5 to 3% by weight, and (D) one or more α,β-monoethylenically unsaturated monomers other than the above... -Relates to a leveling agent for water-based paints made of a copolymer obtained from 0 to 5% saliva.

Many water-based paints using copolymers etc. obtained from amino group-containing monomers and α,β-monoethylenically unsaturated monomers have been known.

(For example, Special Publication No. 45-12395, Special Publication No. 48-3
No. 7147, Special Publication No. 52-7 redundant, Japanese Patent Publication No. 50-157
No. 491, JP-A-52-77143, U.S. Patent No. 36
No. 17458, etc.) However, all of these merely indicate the use as a paint binder, and do not indicate any specific use as in the present invention, that is, use as an additive for water-based paints. ) In the present invention, the dimethylaminoethyl methacrylate component is essential, and this component greatly contributes to the adhesion with the coating film of top coat paints such as alkyd melamine resin paints and acrylic melamine resin paints, and particularly improves the adhesion during overbaking. It is effective for sex.

Furthermore, since this component has water dilutability in the presence of an acid, it also contributes to the dispersion stability of the leveling agent, particularly in cationic electrodeposition paints. A leveling agent using a reaction product of diethylaminoethyl (meth)acrylate, dibutylaminoethicol (meth)acrylate, glycidyl (meth)acrylate and a primary amine or secondary amine, etc., which have a structure similar to the above component. can not be used for purposes such as the present invention because it has poor adhesion to the top coat film, especially during overbaking.

The dimethylaminoethyl methacrylate is used in a proportion of 10 to 7% by weight in the copolymer.

If the amount of the monomer is less than 1%, the adhesion with the top coat film will decrease, and if it exceeds 7%, the coating will have low resistance and a non-smooth coating. Both are unfavorable because they result in a decrease in water resistance, corrosion resistance, etc. of the coating film. The alkyl ester of acrylic acid (the number of carbon atoms in the alkyl group is 1 to 4) used in the present invention has the effect of improving the appearance of the paint film and, like dimethylaminoethyl methacrylate, improves the adhesion to the top coat paint film. Particularly contributes to improving adhesion during overbaking.

Among the alkyl esters of acrylic acid, monomers whose alkyl group has 1 to 2 carbon atoms have particularly excellent adhesion to the top coat film, and monomers whose alkyl group has 3 to 4 carbon atoms has the effect of improving the appearance of the paint film within a range that does not impede the adhesion with the top coat paint film. In the monomer, if the number of carbon atoms in the alkyl group is 5 or more, it has the effect of improving the appearance of the paint film, but it is not suitable for the purpose of the present invention because it impairs the adhesion with the top coat paint film. do not have.

The monomers are used in a proportion of 20 to 85% by weight in the copolymer.

If the amount of the monomer is less than 2%, the effect of improving the adhesion with the top coat paint film and improving the appearance of the paint film will be extremely reduced, and conversely, if the amount of the monomer exceeds 85%, Since the amount of other monomers used is inevitably reduced, neither of these methods can achieve the purpose of the present invention. The above monomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, 1s0-propyl acrylate, n-butyl acrylate, 1s0-butyl acrylate, and Tert
-butyl acrylate, which may be used alone or as a mixture of two or more.

Furthermore, the N-alkoxymethylated monomer of α,β-monoethylenically unsaturated carboxylic acid amide used in the present invention,
The and/or N-methylolated monomer particularly contributes to improving the adhesion with the top coat film using alkyd melamine resin or acrylic melamine resin.

The monomer is used in a proportion of 5 to 3% by weight in the copolymer.

In the above range, if the amount of the monomer used is less than 5% by weight, the adhesion with the top coat coating film will decrease, and if it exceeds 3% by weight, the amount of the monomer used will deteriorate during the process of obtaining the copolymer. Both are unfavorable because they tend to gel. The above monomers include N-methoxymethyl (meth)acrylamide, N
-Ethoxymethyl (meth)acrylamide, N-n-propoxymethyl (meth)acrylamide, N-1S0-
Propoxymethyl (meth)acrylamide, N-n-butoxymethyl (meth)acrylamide, N-Sec-butoxymethyl (meth)acrylamide, N-Tert-
Butoxymethyl (meth)acrylamide, N-IsO-
Examples include N-alkoxymethylated monomers of α,β-monoethylenically unsaturated carboxylic acid amides such as butoxymethyl (meth)acrylamide, or N=methylolated monomers thereof, and these may be used in combination of one or two types. Used as a mixture of the above.

In the present invention, the dimethylaminoethyl methacrylate, the alkyl ester of acrylic acid (the alkyl group has 1 to 4 carbon atoms), and the N-alkoxymethylated monoethylenized α,β-monoethylenically unsaturated carboxylic acid amide are used. α,β-monoethylenically unsaturated monomers other than N-methylolated monomers and/or their N-methylolated monomers are optionally
It is possible to use up to 50% by weight.

The monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate,
-Hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, neopentyl glycol mono(meth)acrylate ) acrylate, 3-butoxy 2-hydroxypropyl (meth)acrylate, 2-hydroxy-1-phenylethyl (meth)acrylate, polypropylene glycol mono(meth)acrylate, glycerin mono(meth)acrylate, etc. Hydroxyalkyl esters of saturated carboxylic acids; α, β- such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, etc.
Monoethylenically unsaturated carboxylic acids: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, IsO-propyl methacrylate, n-butyl methacrylate, Sec-butyl methacrylate, Ter
Alkyl esters of methacnolylic acid such as t-butyl methacrylate and IsO-butyl methacrylate; dialkyl esters of fumaric acid such as glycidyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl methacrylate, benzyl methacrylate, dibutyl fumarate, and styrene. , vinyl 7lutoluene,
Examples include monomers such as α-methylstyrene, (meth)acrylonitrile, and vinyl acetate.

These may be used alone or as a mixture of two or more. The copolymer used as the leveling agent of the present invention is generally produced by a conventional solution polymerization method.

For example, the remaining monomers (mixture) and a polymerization initiator are added dropwise into a mixture of a part of the monomers (mixture) and a polymerization solvent, and the remaining monomers (mixture) and a polymerization initiator are polymerized, or the monomers (mixture)
There are also methods of dropping a polymerization initiator and polymerizing, but there are no particular limitations on the solution polymerization method. Generally, the polymerization temperature range is about 50 to 150°C, and the polymerization reaction time is about 4 to 1'5 degrees Celsius, depending on the temperature. The range is between f. As the polymerization solvent used in the solution polymerization method, water-soluble or water-miscible solvents are used, such as alcohols such as methyl alcohol, ethyl alcohol, IsO-propyl alcohol, and n-propyl alcohol: ethylene glycol monomethyl ether, Ethylene glycol derivatives such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate; diethylene glycol derivatives such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether; methyl acetate, ethyl acetate, butyl acetate, etc. Esters: Ketones such as methyl ethyl ketone and methyl isobutyl ketone are used.

These polymerization solvents may be used alone or in an appropriate combination of two or more. The amount of the polymerization solvent used is such that the nonvolatile content of the copolymer is 10 to 90% by weight, preferably 20 to 8% by weight.
It is preferable to use the range such that

Examples of the polymerization initiator used include organic compounds such as benzoyl peroxide, t-butyl perbenzoate, t-butyl hydroperoxide, cumene hydroperoxide, di-t-butyl peroxide, and t-butyl peroctoate. Examples include peroxides and azo compounds such as azobisisobutyronitrile and azodiisobutyric acid nitrile.

One or more of these polymerization initiators may be used in combination as appropriate. The polymerization initiator is used in an amount of about 0.1 to 15% by weight based on the monomer mixture. Adjust the molecular weight if necessary. Chain transfer agents such as dodecyl mercaptan, 2-ethylhexyl thioglycolate, carbon tetrachloride, etc. may be used to transfer the ester. The chain transfer agent is
It is preferably used in an amount of about 0 to 5% by weight based on the monomer mixture. The copolymer used as the leveling agent of the present invention preferably has a weight average molecular weight in the range of about 4,000 to 80,000, preferably about 5,000 to 50,000.

If the weight average molecular weight is less than 4000 within the above range, the effect of improving the appearance of the coating film will be weak and the performance of the coating film will tend to deteriorate. On the other hand, the weight average molecular weight is 8000
If it exceeds 0, the effect of improving the appearance of the paint film will similarly decrease, and the water dilutability of the copolymer will also decrease, so when it is added to a cationic electrodeposition paint, it will affect the dispersion stability of the paint. This is not desirable as it tends to cause losses. The leveling agent of the present invention thus obtained is 0.5% to 10% by weight based on the resin solid content in water-based paints, particularly cationic electrodeposition paints.
(solid content).

In the above addition range, if it is less than 0.5% by weight, the effect of improving the appearance of the coating film will be very poor;
If it exceeds , it is not preferable because the corrosion resistance, water resistance, etc. of the coating film will deteriorate.

Methods for adding the leveling agent of the present invention include, for example, a method in which the resin for cationic electrodeposition paint is mixed in advance before dilution with water, a method in which the resin for cationic electrodeposition paint is added after dilution with water, etc. There are no particular restrictions on the method. As mentioned above, the leveling agent of the present invention exhibits special effects when added to water-based paints, particularly cationic electrodeposition paints using epoxy resins or urethane resins containing blocked isocyanate groups.

The present invention will be explained below using detailed examples.

Incidentally, unless otherwise specified, 1 part or 1% means 0 part by weight or 0% by weight. Example 1 Ethylene glycol monoethyl ether 100 was added to a reaction vessel equipped with a stirrer, a thermometer, a dropping load and a cooling tube.
After the temperature was raised to 90° C., the following monomers and initiators were added dropwise over 3 hours.

Dimethylaminoethyl methacrylate stamp, 10 parts of methyl acrylate, 25 parts of IsO-butyl acrylate,
5 parts of N-n-butoxymethylacrylamide, 0.5 parts of azobisisobutyronitrile.

After the dropwise addition, 0.25 part of azobisisobutyronitrile was added in 4 portions every 3 gins, and the reaction was further carried out at the same temperature for 4 hours to form a copolymer with a weight average molecular weight of 1230 and a volatile content of 50%. A solution was obtained. (hereinafter referred to as AC-1) Example 2 Ethylene glycol monoethyl ether 100
After the temperature was raised to 90°C, the following monomers and initiators were added dropwise over 3 hours.

Dimethylaminoethyl methacrylate nod, methyl acrylate 5, IsO-butyl acrylate 3? , n-
w parts of butyl acrylate, 1 part of Nn-butoxymethylacrylamide, 5 parts of 2-hydroxyethyl methacrylate, and 0.5 parts of azobisisobutyronitrile.

After the dropwise addition, 0.25 part of azobisisobutyronitrile was added in 4 portions every 3 gins, and the reaction was further carried out at the same temperature for 4 hours, resulting in a weight average molecular weight of 12,000. Non-volatile content 50%
A copolymer solution was obtained.

(hereinafter referred to as AC-2) Example 3 Ethylene glycol monoethyl ether 100
After the temperature was raised to 90°C, the following monomers and initiators were added dropwise over 3 hours.

Dimethylaminoethyl methacrylate part, methyl acrylate part O, ethyl acrylate 10 parts, ISO-butyl acrylate (to) parts, N-methylol acrylamide 5 parts, methyl methacrylate 5 parts, azobisisobutyronitrile 0.5 parts Department.

After the dropwise addition, 0.25 part of azobisisobutyronitrile was added in 4 portions of 3 powders each, and the reaction was further carried out at the same temperature for 4 hours to obtain a weight average molecular weight of 119,001 and a non-volatile content of 50%.
A copolymer solution was obtained. (hereinafter referred to as AC-3) Example 4 Ethylene glycol monoethyl ether 100
After the temperature was raised to 90'C, the following monomers and initiators were added dropwise over 3 hours.

Dimethylaminoethyl methacrylate, 0 parts of ethyl acrylate, IsO-butyl acrylate 2α, N
- methylol acrylamide 2α, 10 parts of styrene,
0.5 part of azobisisobutyronitrile.

After the dropwise addition was completed, 0.25 part of azobisisobutyronitrile was added in 4 portions of 3 powders each, and the reaction was further carried out at the same temperature for 4 hours to obtain a weight average molecular weight of 11,800 and a non-volatile content of 50%.
A copolymer solution was obtained.

(hereinafter referred to as AC-4) Example 5 Ethylene glycol monoethyl ether 100
After the temperature was raised to 90° C., the following monomers and initiators were added dropwise over 3 hours.

Dimethylaminoethyl methacrylate (9) parts, methyl acrylate 15 parts, IsO-butyl acrylate 35 parts
15 parts of Nn-butoxymethylacrylamide, 5 parts of styrene, and 0.5 parts of azobisisobutyronitrile.

After the dropwise addition, 0.25 part of azobisisobutyronitrile was added in 4 portions of 3 powders each, and the reaction was further carried out at the same temperature for 4 hours to obtain a weight average molecular weight of 11,200 and a non-volatile content of 50%.
A copolymer solution was obtained.

(hereinafter referred to as AC-5) Example 6 Ethylene glycol monoethyl ether 100
After the temperature was raised to 90 °C, the following monomers and initiators were added dropwise over 3 hours.

Dimethylaminoethyl methacrylate (t) part, ethyl acrylate 3 (2), n-butyl acrylate 3 (2)
), 10 parts of N-n-butoxymethylacrylamide,
0.5 part of azobisisobutyronitrile.

After the dropwise addition, 0.25 part of azobisisobutyronitrile was added in 4 portions every 3 gins, and the reaction was further carried out at the same temperature for 4 hours to obtain a weight average molecular weight of 13,100 and a non-volatile content of 50%.
A copolymer solution was obtained. (hereinafter referred to as AC-6) Example 7 Ethylene glycol monoethyl ether 100
After the temperature was raised to 90'C, the following monomers and initiators were added dropwise over 3 hours.

35 parts of dimethylaminoethyl methacrylate, 15 parts of ethyl acrylate, 3α of IsO-butyl acrylate, 15 parts of N-methylol acrylamide, 5 parts of methyl methacrylate, 0.5 part of azobisisobutyronitrile.

After the dropwise addition was completed, 0.25 part of azobisisobutyronitrile was added in 4 portions every 3 gins, and the reaction was further carried out at the same temperature for 4 hours to obtain a weight average molecular weight of 119,001 and a non-volatile content of 50%.
A copolymer solution was obtained. (hereinafter referred to as AC-7) Comparative Example 1 Ethylene glycol monoethyl ether 100
After the temperature was raised to 90° C., the following monomers and initiators were added dropwise over 3 hours.

Diethylaminoethyl methacrylate part, methyl acrylate 20 parts, IsO-butyl acrylate part, N
-n-butoxymethylacrylamide additive, 0.5 part of azobisisobutyronitrile.

After the dropwise addition, 0.25 part of azobisisobutyronitrile was added in 4 portions every 3 gins, and the reaction was further carried out at the same temperature for 4 hours to obtain a weight average molecular weight of 12,400 and a non-volatile content of 50%.
A copolymer solution was obtained. (hereinafter referred to as AC-8) Comparative Example 2 Ethylene glycol monoethyl ether 100
After the temperature was raised to 90'C, the following monomers and initiators were added dropwise over 3 hours.

16.5 parts of glycidyl methacrylate, 1 part of methyl acrylate, 3 parts of n-butyl acrylate. - Methyloacrylamide additive, 0.5 part of azobisisobutyronitrile.

After the dropwise addition was completed, 0.25 part of azobisisobutyronitrile was added in 4 portions of 3 powders each, and the reaction was further carried out at the same temperature for 4 hours, and then the reaction temperature was increased to 120°C. 13.5 parts of diethanolamine was added and the reaction was further carried out for 2 hours to obtain a copolymer solution with a weight average molecular weight of 1000 and a non-volatile content of 50%.

(hereinafter referred to as AC-9) Comparative Example 3 Ethylene glycol monoethyl ether 100
After the temperature was raised to 90° C., the following monomers and initiators were added dropwise over 3 hours.

Methyl acrylate, ethyl acrylate, I
sO-butyl acrylate 50 parts, N-methylolacrylamide (a) part, azobisisobutyronitrile 0.
Part 5.

After the dropwise addition, 0.25 part of azobisisobutyronitrile was added in 4 portions of 3 powders each, and the reaction was further carried out at the same temperature for 4 hours to obtain a weight average molecular weight of 12,400 and a non-volatile content of 50%.
A copolymer solution was obtained.

(hereinafter referred to as AC-10) Comparative Example 4 Ethylene glycol monoethyl ether 100
The following monomers and initiators were added dropwise over 3 hours.

A part of 2-ethylhexyl acrylate, 2 parts of N-n-butoxymethylacrylamide, 0.5 part of azobisisobutyronitrile.

After the dropwise addition was completed, 0.25 part of azobisisobutyronitrile was added in 4 portions every 3 gins, and the reaction was further carried out at the same temperature for 4 hours to obtain a weight average molecular weight of 130001 and a non-volatile content of 50%.
A copolymer solution was obtained.

(hereinafter referred to as AC-11) Comparative Example 5 Ethylene glycol monoethyl ether 100
After the temperature was raised to 90° C., the following monomers and initiators were added dropwise over 3 hours.

2-ethylhexyl acrylate part a, styrene added part,
0.5 part of azobisisobutyronitrile.

After the dropwise addition, 0.25 part of azobisisobutyronitrile was added in 4 portions every 3 gins, and the reaction was further carried out at the same temperature for 4 hours to obtain a weight average molecular weight of 135,001 and a non-volatile content of 50%.
A copolymer solution was obtained. (hereinafter referred to as AC-12) Reference Example 8 cationic resins shown in Table 1 were taken as solids, and a predetermined amount of the leveling agent was added and mixed.

Thereafter, a 10% acetic acid aqueous solution as a neutralizing agent was added until the pH reached 5.
After addition and mixing so that the solid content was within the range of 5 to 6.5, ion-exchanged water was gradually added to dilute the solid content to 40%. To the aqueous solution, n part of titanium white and 0.0 part of carbon black were added.
After adding 6 parts and 0.1 part of antifoaming agent and dispersing with a sand mill, the dispersion was diluted with ion-exchanged water to give a solid content of about 2
A 0% cationic electrodeposition paint was obtained. While stirring the paint, place the zinc phosphate treated tall copper plate (a) in it. 8x70
×150Tm1n) was electrodeposited at 29°C for 12 minutes, then washed with ion-exchanged water, and then baked and dried under predetermined baking conditions. The voltage was set so that the film thickness after baking was 20μ. The electrodeposition equipment used for the above painting included an O~500V rectifier, a box-shaped electrodeposition tank made of approximately 3.5' polyvinyl chloride, a magnetic stirrer, and a carbon electrode (5 x 70 x 150
Tr0rL, distance between electrodes approximately 10α).
The appearance (degree of dents) of the electrodeposited coating film thus obtained was visually evaluated.

The results are shown in Table-1. Next, an alkyd melamine resin paint or an acrylic melamine resin paint was spray-painted on the electrodeposited film so that the dry film thickness was 35 μm, and after being set for 1 gin, it was baked and dried at 150°C for 12 gin, and then subjected to a comparative test. . Note 1) Addition amount (solid content) based on solid content (1) part of cationic electrodeposited resin Note 2) Indentation of 3 test pieces obtained by washing with water and baking at 180°C for 20 minutes after full-surface electrodeposition coating The numbers were counted, averaged, and evaluated using the following criteria.

Furthermore, a top coat was applied, baked at 180°C for 2 minutes, and evaluated in the same manner. ○...Average number of dents per test piece 0-1 Δ...Average number of dents per test piece 2-1
10j pieces×...Average number of dents per test piece: 11 or more Note 3) Alkyd melamine resin paint: Dainippon Paint
Manufactured by Co., Ltd. Product name Delicon #8501 Note 4) JIS-D-
Evaluation was made according to the following criteria based on the test method (Type 1) described in 0202, 8.12.

(Number of remaining meals/Number of prepared meals) ○...10
0/1002 Δ...90/100~60/100 ×...59/100~20/100 ×X...19/100~0/100 Note 5) Acrylic melamine resin paint: Dainippon Paint Co., Ltd. ) Product name: Acrose #100 Note 6) After soaking in pure water at 40'C for a certain period of time, the sample was taken out and left for one day, and tested using the same test method as for primary adhesion.

The evaluation criteria were the same as those for primary adhesion. Note 7) JIS
-800 hours of chloride spraying using Z-2371 (removal of cellophane tape at cut area) Evaluation criteria: Peeling width on one side (
(Including peeling width of top coat only) 0...0~
3wrm Δ...3 to 6rfrIn x...6Tfrm or more Note 8) The pump stability test method shown below was used.

The pump used is Iwakirabo Pump LP-15, and the frequency is 50°. The operating time is 24 hours, the operating paint temperature is 29°C, the amount of paint is 1k9, and the nonvolatile content of the paint is 20%. After passing the paint through a 300-mesh wire mesh, a pump stability test was conducted and a 200-mesh
Pour through the wire mesh of Tsushiyu and air dry the remaining material.
After that, weigh the remaining amount. 0...Remaining amount is 100m9 or less Δ...Remaining amount is 100m9
~500m9×...The remaining amount is 500m9 or more Note 9
) Baking conditions for electrodeposition coating Note 10) Tolylene diisocyanate and polypropylene
A reaction product obtained by reacting lene glycol with an excess of NCO was reacted with triethanolamine to obtain a reaction product a having a cationic functional group and a hydroxyl group.

Separately, a monoblock isocyanate compound b of tolylene diisocyanate and 2-ethylhexanol was obtained. The reaction product a and the monoblock isocyanate compound b were reacted to obtain a cationic aminated urethane resin. Note 11
) A bisphenol type epoxy resin and triethanolamine were reacted to obtain a reaction product c having a cationic functional group and a hydroxyl group.

The reaction product c was reacted with the same monoblock isocyanate compound b used to obtain the cationic aminated urethane resin to obtain a cationic aminated epoxy resin. It is clear from the above comparison test result table that the cationic electrocoating paint films without leveling agent (Samples Nos. 13 and 14) had significant dents, and these not only caused poor appearance even after the top coat was applied. , water resistance and corrosion resistance were also poor.

However, when the leveling agent of the present invention is added to such paints (Samples No. 1 to 7), the appearance of the electrodeposited paint film is significantly improved, and the interlayer adhesion with the top coat paint film is completely impaired. Moreover, the dispersion stability of the coating material was also extremely good.

Claims (1)

[Claims] 1(A) Dimethylaminoethyl methacrylate...
...10 to 70% by weight, (B) one or more alkyl esters of acrylic acid (alkyl group has 1 to 4 carbon atoms)...20 to 85% by weight, (C) N-alkoxymethylated monomer of one or more α,β-monoethylenically unsaturated carboxylic acid amides and/or
or N-methylolated monomer...5 to 30% by weight, and (D) one or more α,β-monoethylenically unsaturated monomers other than the above... A leveling agent for water-based paints consisting of a copolymer obtained from 0 to 50% by weight.