JPS6011758B2 - Aqueous coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aqueous coating composition, and more particularly to an aqueous coating composition useful as a cold-curing rust-inhibiting coating composition and a coated top coating composition.

Recently, water-based paints have been attracting attention as non-polluting paints.

These water-based paints are mainly of two types: types using water-soluble resins and emulsion types. However, water-based paints using emulsions cannot be said to have sufficient anti-corrosion properties due to the large molecular weight of the emulsions, the poor leakage of the particles to metal surfaces, and the characteristic of emulsions to form porous coatings. . On the other hand, water-soluble resins can exhibit a high degree of shine, but because they have a large amount of hydrophilic components to make them water-soluble and have a small molecular weight, they cannot avoid the drawbacks of poor water resistance and durability even after drying.

The present inventors have made earnest efforts to develop an aqueous coating composition that does not have these conventional defects, and as a result, they have arrived at the present invention.

That is, the present invention uses Q- The main vehicle components are an emulsion 1 obtained by emulsion polymerization of a polymerizable vinyl monomer having a Q value of at least 0.1 and an oxidatively crosslinked water-soluble or water-dispersible resin (like material) 0. The present invention relates to aqueous coating compositions. Vinyl polymer emulsion 1 used in the present invention
can be obtained as follows.

First, drying oil fatty acid and/or semi-drying oil fatty acid (
Hereinafter, it will be abbreviated as unsaturated fatty acid.

) and an acrylic polymer obtained by radical polymerization are ester-bonded, and the fatty acid-modified acrylic polymer is an acrylic polymer whose main chain is obtained by radical polymerization, and whose side chain has oxidative curability. It is a high molecular weight polymer that is a drying oil fatty acid residue and/or a semi-drying oil fatty acid residue. As a method for producing this high molecular polymer, for example, a fatty acid-modified pinyl monomer containing an unsaturated fatty acid residue is produced in advance, and then a 3-ethylenically unsaturated acid and a Q,B-ethylenically unsaturated acid are combined with this monomer. A method for obtaining a fatty acid-modified acrylic polymer by copolymerizing saturated monomers. An acrylic polymer having a carboxyl group and a main chain consisting of a carbon-carbon bond is synthesized, and this polymer is combined with an unsaturated fatty acid and Examples include a method of obtaining a fatty acid-modified acrylic polymer by subjecting a fatty acid-modified epoxy group-containing compound, which is an adduct with jepoxide, to an addition reaction. In the case of the former method, unsaturated fatty acids having non-conjugated double bonds are mainly used since gelation occurs during polymerization if fatty acids having conjugated double bonds are used as the unsaturated fatty acids.

In addition, the Q,8-ethylenically unsaturated monomer has a Q value of 0.1 or more in the Q,e theory so as not to destroy the active sites that enable easy copolymerization and oxidative hardening of unsaturated fatty acids. Q of
, B - must be an ethylenically unsaturated monomer. When using the latter method, unsaturated fatty acid groups are introduced into the previously obtained carboxyl group-containing acrylic polymer by an addition reaction between carboxyl groups and epoxy groups. There is no limitation on the ethylenically unsaturated monomer. Next, each component used in the former method will be described.

Bag oil fatty acids and semi-drying oil fatty acids with non-conjugated double bonds include safflower oil fatty acids, linseed oil fatty acids, soybean oil fatty acids, sesame oil fatty acids, poppy oil fatty acids, enoic oil fatty acids, and hempseed oil fatty acids. , grape kernel fatty acid, corn fatty acid, tall oil fatty acid, sunflower oil fatty acid, cottonseed oil fatty acid, walnut oil fatty acid, rubber seed oil fatty acid, etc. In addition,
If necessary, a conjugated fatty acid such as tung oil fatty acid, oticica oil fatty acid, dehydrated castor oil fatty acid, or high-density fatty acid may be added together with the above-mentioned unsaturated fatty acid having a non-conjugated double bond, and in this case, the use thereof. The amount is not more than 8% by weight of the total amount of unsaturated fatty acids.

If more than 3% by weight is used, gelation will occur during copolymerization, which is not preferable.

The other component for obtaining the fatty acid-modified vinyl monomer is a glycidyl ester of a Q,8-ethylenically unsaturated acid or a Q,8-ethylenically unsaturated monomer having a hydroxyl group.

Glycidyl esters of Q,8-ethylenically unsaturated acids include glycidyl acrylate and glycidyl methacrylate, and examples of Q,8-ethylenically unsaturated molecules having hydroxyl groups include 2-hydroxyethyl acrylate and 2-hydroxyethyl acrylate. Examples include hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, and 2-hydroxybutyl methacrylate. Glycidyl ester of Q,8-ethylene unsaturated acid is 0.8 to 1.2 mol per 1 mol of unsaturated fatty acid, and Q,8-ethylene unsaturated monomer having a hydroxyl group is 0.8 to 1.2 mol per 1 mol of unsaturated fatty acid. The reaction is usually carried out at a ratio of 0.8 mol or more. In addition, the Q,8-ethylenically unsaturated acids copolymerized with the fatty acid-modified monomer to obtain the fatty acid-modified acrylic polymer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid. etc., and the copolymerized Q,
The Q,8-ethylenically unsaturated monomer having a Q value of 0.1 or more according to the e theory has the general formula C&=CR. COOR2 (However, R is hydrogen or a methyl group, R2 is a carbon number of 1 to
18 alkyl group), methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxybutyl acrylate, ethoxybutyl methacrylate, allyl acrylate, allyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, diethylaminoethyl methacrylate, allyloxyethyl acrylate, allyloxyethyl methacrylate , styrene, Q-methylstyrene, vinyltoluene,
These include vinylpyridine, butadiene, isoprene, chlorobrene, acrylonitrile, methacrylonitrile, N-methylolacrylamide, N-butoxymethylacrylamide, and the like.

These polymerizable vinyl monomers may be used alone or in combination of two or more.

Unsaturated monomers (such as vinyl acetate) whose Q value does not reach 0.1 are undesirable because they tend to gel during the copolymerization reaction. The blending ratio of each monomer is usually such that the amount of unsaturated fatty acids, which are the constituent components of the fatty acid-modified monomer, is 5 to 6% by weight, preferably 20 to 6% by weight. The Q,8-ethylenically unsaturated acid is blended in an amount of 5 to 2% by weight, that is, the acid value is 40 to 180, and the remainder is blended with a Q,8-ethylenically unsaturated acid having a Q value of 0. Q of 1 or more,
It may be an 8-ethylenically unsaturated monomer. Next, each component used in the latter method will be shown.

The epoxy group-containing compound into which an unsaturated fatty acid has been introduced by an addition reaction can be obtained by addition-reacting a jepoxy compound with a drying oil fatty acid or a semi-drying oil fatty acid in an equimolar amount. As the drying oil fatty acid and the semi-drying oil fatty acid, both non-conjugated fatty acids and conjugated fatty acids used in the former method can be used.

As the jepoxy compound, bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, etc. are used.

The Q,8-monounsaturated acid used to introduce a carboxylic acid group into the main chain of the acrylic polymer and the Q,8-ethylenically unsaturated monomer used in the former method are Q,6, respectively. - Ethylenically unsaturated acids and Q,3-ethylenically unsaturated monomers can be used.

The blending ratio of each component is usually such that the basic oil fatty acid and/or semi-drying oil fatty acid is used so that the fatty acid oil length in the fatty acid-modified acrylic polymer is 5 to 6, preferably 20 to 65.
, 8-ethylenically unsaturated acid is a fatty acid-modified acrylic polymer whose acid value is 40 after a complete addition reaction between a polymer primary mirror having a carboxylic acid and an epoxy group-containing compound into which an unsaturated fatty acid has been introduced. Use at a ratio of ~180.

Thus, the number average molecular weight of the fatty acid-modified acrylic polymer obtained by the method of
0 to 50,000, preferably about 1,000 to 15,000. If the molecular weight is lower than 500, the water resistance and solvent resistance of the coating film will be poor, and if it is higher than 50,000, the viscosity will be high and it will be difficult to form an emulsion. The fatty acid-modified acrylic polymer obtained as described above is neutralized and water-solubilized using a neutralizing agent and then subjected to an emulsifying agent. As the neutralizing agent, ammonia, amine, alkali metal compound, etc. are used.

The above is a method for producing a fatty acid-modified acrylic polymer. Considering the ease of production, the former method is Q.
It is desirable to obtain a polymer from a glycidyl ester of an 8-ethylenically unsaturated acid and an unsaturated fatty acid having a nonconjugated double bond through a fatty acid-modified monomer.

The emulsion, which is the component (1) of the present invention, uses the emulsifier obtained as described above, and the Q
It is obtained by emulsion polymerization of a polymerizable vinyl monomer having a value of at least 0.1.

Although a wide variety of polymerizable vinyl monomers can be used, it is not preferable to use a large amount of a highly hydrophilic monomer as in the case of general emulsion polymerization.

Such polymerizable vinyl monomers have, for example, the general formula C ratio: C(R2)COOR2 (where R is hydrogen or a methyl group, when R is hydrogen, R2 is an alkyl group having 2 to 26 carbon atoms, and R is methyl). acrylic acid ester or methacrylic acid ester, glycidyl methacrylate, represented by R represents an alkyl group having 1 to 26 carbon atoms,
Glycidyl acrylate, glycidyl methacrylate, or adduct of glycidyl acrylate with a carboxylic acid having 1 to 26 carbon atoms, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, or diethylene glycol monoalkyl ether (with an alkyl group) Esterified products of acrylic acid or methacrylic acid (having 1 to 8 carbon atoms), allyl acrylate, allyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, acrylic acid or methacrylic Adduct of acid and Cardular E (manufactured by Shell Chemical Co., Ltd., trade name),
Jetylaminoethyl methacrylate, allyloxyethyl acrylate, allyloxyethyl methacrylate, styrene, vinyltoluene, Q-methylstyrene, butadiene, bendadiene, isoprene, chloroprene,
Examples include methacrylonitrile.

These polymerizable vinyl monomers may be used alone or in combination of two or more. The ratio of the emulsifier and these polymerizable vinyl monomers used in the preparation of emulsion 1 is such that the acid value of the total solid content of the resulting emulsion before neutralization is preferably about 3 to 150, more preferably about 15 to 30. is desirable.

Further, the solid content concentration of the emulsion composition is approximately 15 to 65%.
is preferred. In the aqueous coating composition of the present invention, an oxidatively crosslinked water-soluble or water-loving resin (like material) is used in combination with Emulsion 1 as the main vehicle component. Neutralized maleated and/or fumarated products of oil, semi-drying oil, synthetic oil or processed oil, {2) neutralized product of maleated alkyd resin, '3} drying oil fatty acid residue and/or semi-drying oil Neutralized maleated product of addition polymerization polymer having fatty acid residue as the side head, [4] A structure in which drying oil fatty acid and/or semi-hostile oil fatty acid and acrylic polymer obtained by radical polymerization are ester-bonded. Neutralized products of water-lacquered or water-dispersible fatty acid-modified acrylic polymers and neutralized products of '51 maleated polyptadiene-based polymers can be mentioned.

The method for producing these oxidatively crosslinked water-soluble or water-dispersible resins (like substances) of '1' to '5' will be described below. [
1) To obtain a neutralized maleate and/or fumarate of baggage oil, semi-intoxicating oil, synthetic oil or processed oil,
Maleic acid and maleic anhydride are added to synthetic or processed oils such as bag or semi-drying oils and boiled oils, stand oils, esterified oils, styrenated oils, urethanized oils, and cyclobentagenated oils used to create the emulsifier of Emulsion 1. What is necessary is to neutralize the acid or fumaric acid that has been subjected to an addition reaction and has an acid value of 20 to 200.

'21 To obtain a neutralized maleated alkyd resin,
It is obtained by reacting a polyhydric alcohol, a polybasic acid, and a baggy or semi-drying oil fatty acid.

Oil length 20-88, acid value 20-300, number average molecular weight 50
After maleating the alkyd resin of 0 to 10,000, it may be neutralized. {31 In order to obtain a neutralized product of a maleated product of an addition polymer having a drying I-type fat acid residue and/or a semi-enemy oil fatty acid residue as a side chain, a drying fat with a fatty acid oil length of 10 to 90 is used. What is necessary is to neutralize a product obtained by adding maleic acid, maleic anhydride or fumaric acid to costal acid and/or semi-degradable oil fatty acid and having an acid value of 20 to 200.

{4' To obtain a neutralized water-soluble or water-dispersible fatty acid-modified acrylic polymer, exactly the same method as that used to prepare the emulsifier used in preparing Emulsion 1 is used.

(2) To obtain a neutralized maleated polybutadiene polymer, the number average molecular weight is about 200 to 40,000, preferably about 500 to 10,000.

A polybutadiene homopolymer or a butadiene copolymer having the above number average molecular weight containing 1% by weight or more, preferably 4% by weight or more as butadiene units, or a homopolymer or copolymer thereof, by hydrogenation or A modified product modified by a cyclization reaction or the like is treated with maleic acid or maleic anhydride to give an acid value of 20 to 35.
What is necessary is just to neutralize what is maleated so that it may be 0, preferably 40-200. Obtained as above,
The oxidatively crosslinked water-soluble or water-dispersible resin of the present invention (
When the acid value is 20 or less, the water solubility and water dispersibility are poor, and when the acid value exceeds each upper limit, the resulting film has insufficient water resistance.

In addition, when obtaining the water-soluble or water-dispersible resin (like substance) of the oxidized maiken-kyo type of [11 to [51] above, the neutralizing agent used for neutralization is ammonia, amines, or alkali metal hydroxide. Examples include compounds, oxides, carbon salts, and bicarbonates. The blending ratio of 1 and 0 in the silk composition of the present invention can be determined within a wide range, but preferably, the solid content weight ratio (1) component/(2) component = 95/5/95, especially 90
The range of /10 to 10/90 is preferable.

If the blending ratio of component (1) and component (□) deviates from the above range, problems will arise in the drying properties, weather resistance, corrosion resistance, etc. of the coating film. To create this composition, all the ingredients need to be mixed together, and in addition, ordinary coloring pigments, anti-rust pigments, dryers,
There is no problem in adding thickeners, antifoaming agents, and other additives.

Although the composition of the present invention is sufficiently cured at room temperature, it may also be cured by heating.

The coating composition of the present invention is characterized not only by its excellent weather resistance, corrosion resistance, and drying properties, but also by the fact that it provides a high-gloss coating film, and furthermore, it has excellent coating workability, especially brush application workability. It has excellent properties that make it useful as an industrial material. The present invention will be explained below with reference to production examples and examples.

Note that parts and % indicate parts by weight and % by weight, respectively, unless otherwise specified. Production example 1 286 parts of linseed oil fatty acid, 1 part of glycidyl methacrylate
$ parts, 0.4 parts of hydroquinone, and 0.2 parts of tetraethylammonium furomide were placed in a reaction vessel and reacted for about 4 hours at a temperature of 140 to 150 Q○ with stirring to obtain an addition reaction product.

Next, 100 parts of n-butyl cellosolve was placed in a reaction vessel, heated to 120 oo, and added to a mixture of the above addition reaction product 4, 47 parts of n-butyl methacrylate, and 18 parts of acrylic acid, 2,2'-azobis-2, Add 7 parts of 4-dimethylvaleronitrile and stir in a nitrogen stream for 12 hours.
At 0:00 pm, the reaction was carried out for 8 hours.

After the reaction was completed, 75 parts of butyl cellosolve was distilled to obtain a polymer with a polymerization rate of 99.5%, an acid value of 91, and a solid content of 80%. To this reactant 10, 8 parts of 28% ammonia water was added to make it water-soluble. , 52 parts of water is added to this to obtain a resin varnish with a solid content of 50%. Production Example 2 320ml of the resin solution obtained in Production Example 1 was dissolved in 6702ml of water.

Furthermore, 16 days of ethylene glycol monobutyl ether was added, stirred well to dissolve it thoroughly, and then 414 days of n-butyl methacrylate was added and the suspension was well-framed. Add the ingredients prepared in the 20th century, heat the mixture at 80℃, and react for 2 hours to obtain an emulsion. Production Example 3 820 g of the resin solution obtained in Production Example 1 was dissolved in 670 g of water.

Furthermore, 14 parts of butyl cellosolve was added and dissolved well, followed by 207 parts of styrene and 2 parts of 2-ethylhexyl methacrylate.
After adding 0.7 ml of water and stirring well to form an emulsion, add 1 ml of ammonium persulfate dissolved in 20 ml of tap water, heat while stirring well, and keep at 80°C for 2 hours to obtain an emulsion. Production Example 4 Gardner Foam Stand linseed oil with a viscosity of M to N (20 qC), 1,132 ml of maleic anhydride, and a small amount of toluene were placed in a two-piece flask and heated at 200°C.
After a period of reaction, a maleated stand linseed oil with a spin value of 96 was obtained.

Furthermore, after neutralizing this with ammonia, the solid content was reduced to 50 with water.
% to obtain a resin varnish. Production Example 5 RJ-101 (number average molecular weight 1150, OH content 7.
7% styrene-allylic alcohol copolymer, manufactured by Monsanto Chemical) 1641, soybean oil and fat 208
0, xylene 200, and dibutyltin oxide 3
．． 3. Put 5.4 into a flask and dehydrate while 2.
The reaction was carried out at 30:00 for one holding period to obtain a resin having a strength of 5.47.

Add 454 ml of maleic anhydride to this to make it 190-200
The maleation reaction is carried out for 7 hours at qo. After removing xylene and maleic anhydride from the reaction by vacuum deposition, the ring is opened with water and ethylene glycol monobutyl ether is added to obtain a resin varnish with a total acid value of 104 and a half acid value of 96 and a solid content of 30%. . Production Example 6 3 Put 404 parts of phthalic anhydride, 523 parts of bentaerythritol, 2573 parts of linseed oil fatty acid, 175 parts of xylene, and 7 parts of dibutyltin oxide into the reaction vessel, and add 7 parts of phthalic anhydride at 230 qo in the presence of nitrogen. I reacted for a while.

An alkyd resin having an acid value of 3.0 was obtained. 2. The alkyd resin 188 base and 15 parts of maleic anhydride were placed in the reaction vessel and reacted for 9 hours at 190 qo in the presence of nitrogen.

The reaction mixture was cooled to 10,000 ml, 55 parts of water was added, and 100 ml of
The reaction was carried out for 3 hours at qo. A maleated alkyd resin solution with a resin acid value of 106 and a resin solid content of 92.4% was obtained.
10 parts of this resin solution, 20 parts of butylcellosolp
10.6 parts of 28% ammonia water was added to neutralize the mixture, and the mixture was dissolved in water to obtain a resin varnish with a solid content of 50%. Production example 7 Polybutadiene A (molecular weight 19001, 4-cis type 72
%, 27% 1,4-trans type and 1% 1,2-vinyl type) 150%, maleic anhydride 20% and xylene 7$C. The mixture was sealed in an autoclave, thoroughly replaced with nitrogen gas, and then heated at 190 to 200 qo for 5 hours under high-speed rotation for reaction.

After the reaction, wash well with water and add C.I. to butyl cellosolve 6.
is added and water is removed using an evaporator to obtain a maleated polybutadiene solution.

The saddle value of maleated polybutadiene is 9 & the concentration is 85.6
%. Next, take 100 pieces of this and add 8% of 28% ammonia water. Foundation C. Neutralize while stirring and dissolve in water to obtain a 60% resin varnish. Example 1 After adding 27 parts of clean water to 4 parts of the resin varnish obtained in Production Example 1, 8 parts of titanium dioxide and 1 part of Antifoam B (manufactured by Toray Silicon ■, trade name) as an antifoaming agent. 0.1 part and 0.8 part of cobalt naphthenate and lead naphthenate were added as metal amounts as a dryer, respectively, and dispersed in a bevel ball mill so that the pigment particle size was 10 or less to obtain a pigment paste.

Next, 20 pieces of the emulsion obtained in Production Example 3 were added to the paste and stirred well. Thereafter, 8 parts of a 10% polypynylpyrrolidone aqueous solution was added to increase the viscosity, and the mixture was thoroughly mixed again to obtain an aqueous coating composition with a viscosity of 90 KU. Example 2
~13 An aqueous coating composition having a viscosity of 90 KU was prepared using the same method as in Example 1.

The formulation is as shown in Table 1. Table 1 (parts by weight) Comparative Example 1 92 parts of the resin varnish obtained in Production Example 6, butyl cellosolve 2
0 parts, 30 parts of 10% polyvinylpyrrolidone aqueous solution, 5 parts of antifoaming agent Antiform B, and cobalt naphthenate,
The metal content of lead naphthenate is 0.25 parts and 0.75 parts, respectively.
194 parts of titanium oxide, and 10 parts of tap water were uniformly mixed in a fly mill, and dispersed through a sand mill until the particle size was 10 mm to obtain a pigment base.

Next, 508.8 parts of acrylic copolymer emulsion Acronal 29 [solid content concentration 48%, manufactured by Mitsubishi Yuka ■, trade name] was placed in a tank, and the above pigment base was added thereto evenly. Water was added to obtain an aqueous coating composition with a viscosity of 90 KU. Comparative Example 2 A pigment base was prepared in the same manner as Comparative Example 1, and Sebian A461, which is a copolymer emulsion of acrylic and styrene, was prepared.
91 [Solid content concentration 46%, manufactured by Daicel ■, product name] 58
Take 0.4 parts in a tank, add the above pigment base while stirring, mix until homogeneous, add water and adjust to a viscosity of 90K.
An aqueous coating composition of U was obtained.

Comparative Example 3 166.2 parts of the resin varnish obtained in Production Example 6, 2 parts of butyl cellosolve, 3 parts of 10% polyvinylpyrrolidone aqueous solution, 5 parts of antifoaming agent Antiform B, and cobalt naphthenate and lead naphthenate in metal amounts. 0.25 parts and 0.25 parts, respectively.
75 parts, iron oxide 20 parts, calcium molybdate 10 parts
The base part and 211 parts of tap water were uniformly mixed using a touzusa machine, and dispersed through a sand mill until the particle size became 30 mm to obtain a pigment base.

Next, Brimar A is an acrylic emulsion.
Put 448.8 parts of C-84 [solid content concentration 45%, made by Nippon Acrylic Column, trade name] into a tank, add the above pigment base while holding a light, mix until homogeneous, add water, and make a mixture with a viscosity of 90 KU. An aqueous coating composition was obtained. The aqueous coating compositions obtained in Examples 1 to 13 and Comparative Examples 1 to 3 were
The dry film thickness is 45-50 on the steel plate on the 50 x 70 x 0.8 side.
Apply thoroughly, temperature 20oo, relative humidity 75%
It was dried for 7 days under the following conditions and used for testing.

Test method Water resistance: The coating film was immersed in 20 oo of tap water and the presence or absence of any abnormalities occurring in the coating film was observed.

Salt water resistance: The coating film was immersed in 20 qo of 3% salt water and the presence or absence of any abnormalities occurring in the coating film was observed.

Salt water fog resistance: A test plate with a cross cut that reaches the substrate is placed in a salt water mist device spraying 35DO, 5% salt water, and the presence or absence of any abnormalities occurring in the coating film is observed. did.

Workability: Using a horsehair flat brush, 900 x 600 x 0.8
It was applied to the steel plate of the ribs and the quality of brushing was observed.

Outdoor peelability: A test plate with a cross cut that reached the substrate was placed outdoors and the presence or absence of any abnormalities in the coating film was observed.

The test results are shown in Table 2, and it can be seen that the aqueous coating composition of the present invention has excellent performance.

Table 2

Claims (1)

[Claims] 1. As an emulsifier, a neutralized water-solubilized product of a fatty acid-modified acrylic polymer having a structure in which a drying oil fatty acid and/or a semi-drying oil fatty acid and an acrylic polymer obtained by radical polymerization are ester bonded. , emulsion I obtained by emulsion polymerization of a polymerizable vinyl monomer having a Q value of at least 0.1 according to the Q-e theory, and an oxidatively crosslinked water-soluble or water-dispersible resin (like substance) II are mainly used. An aqueous coating composition serving as a vehicle component. 2 The oxidatively crosslinked water-soluble or water-dispersible resin (like material) II is (1) a neutralized product of maleated or fumarized drying oil, semi-drying oil, synthetic oil or processed oil, (2) maleic (3) Neutralized product of maleated addition polymer having drying oil fatty acid residue and/or semi-drying oil fatty acid residue as side chain, (4) Drying oil fatty acid and/or Neutralized fatty acid-modified acrylic polymer having a structure in which a semi-drying oil fatty acid and an acrylic polymer obtained by radical polymerization are ester bonded or (5)
The aqueous coating composition according to claim 1, which is a neutralized product of a maleated polybutadiene polymer. 3 A fatty acid-modified acrylic polymer copolymerized with a fatty acid-modified vinyl monomer containing an unsaturated fatty acid residue, an α,β-ethylenically unsaturated acid, and an α,β-ethylenically unsaturated monomer An aqueous coating composition according to claim 1.