JPH0152405B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel oxidation-curing aqueous coating composition, and more particularly, it contains a drying oil fatty acid residue or a semi-drying oil as a film-forming component to enable oxidative curing. Regarding an oxidation-curing water-based coating composition containing a water-soluble or water-dispersed copolymer having a fatty acid residue and a urethane bond or urea bond in the side chain for imparting secondary cohesive force to the resin. .

Several oxidation-curing aqueous coating compositions have been known, but water-soluble or water-dispersible resins (hereinafter referred to as "aqueous resins") are used as film-forming components in these known compositions. Generally, alkyd resins and fatty acid-modified acrylic resins are widely used. These water-based resins are easy to manufacture and available, easy to handle when prepared into a coating composition, and cost-effective compared to other water-based resins. Widely used.

However, conventional water-soluble alkyd resins
Since it contains many ester bonds in its main chain, it is easily hydrolyzed when stored in an aqueous solution. Therefore, aqueous coating compositions containing the alkyd resin generally have poor storage stability, and the films formed therefrom have the disadvantages of poor initial hardness and lack of performance such as water resistance and alkali resistance. Ta.

In addition, fatty acid-modified water-soluble acrylic resins are usually obtained by copolymerization of fatty acid-modified vinyl monomers, α, β-ethylenically unsaturated carboxylic acids, and other copolymerizable unsaturated monomers. Since the main chain of the resin is a carbon-carbon bond, the aqueous coating composition containing the acrylic resin has excellent storage stability, and the initial hardness of the coating formed from the composition is lower than that of the acrylic resin. It has the advantage that it can be adjusted as desired by appropriately selecting the copolymerizable unsaturated monomer component of the resin.
However, since the acrylic resin lacks secondary cohesion, when trying to increase the hardness of the cured coating formed from it, the paintability (processability) of the coating composition is affected.
On the other hand, if the coating composition is improved in paintability, the hardness of the resulting cured film tends to be insufficient. There was a big drawback that there was no.

Furthermore, since the coating formed from the coating composition contains a considerable amount of relatively low molecular weight components in which the acrylic resin in the composition has not sufficiently polymerized, It had the disadvantage of exhibiting a poor texture due to the long-term tackiness of the coating surface.

The present inventors have discovered that the film does not have the above-mentioned drawbacks, that is, it is possible to provide a film with well-balanced performance in terms of hardness and paintability (workability), and it also has a texture based on tackiness. In order to obtain a resin for aqueous coatings that does not exhibit any adverse effects, intensive studies have been conducted on the introduction of urethane bonds or urea bonds, which have extremely strong secondary cohesive force, into the resin skeleton.

As a result, the present inventors have developed an isocyanate-modified acrylic monomer consisting of a reaction product of an acrylic monomer selected from hydroxyl group-containing acrylic monomers and amino group-containing acrylic monomers and an isocyanate compound. is obtained by copolymerizing with a specific fatty acid-modified vinyl monomer, α, β-ethylenically unsaturated carboxylic acid, and other unsaturated monomers. The introduced resin is extremely effective as a resin component of an aqueous coating composition that provides a well-balanced film hardness and paintability and does not exhibit poor texture due to stickiness. This discovery led to the completion of the present invention.

Thus, according to the present invention, (A) an acrylic monomer selected from glycidyl group-containing vinyl monomers and hydroxyl group-containing vinyl monomers, and an unsaturated fatty acid selected from drying oil fatty acids and semi-drying oil fatty acids. a fatty acid-modified vinyl monomer consisting of an addition or condensation reaction product; (B) an acrylic monomer selected from hydroxyl group-containing acrylic monomers and amino group-containing acrylic monomers and an isocyanate compound; Isocyanate-modified acrylic monomer consisting of a reaction product; (C) α,β-ethylenically unsaturated carboxylic acid; and (D) the above monomers (A), (B) and/or (C) and a radical There is provided an oxidation-curable aqueous coating composition comprising a water-soluble or water-dispersible resin obtained by copolymerizing a copolymerizable unsaturated monomer. Ru.

In the present invention, the "glycidyl group-containing vinyl monomer" used to form the fatty acid-modified vinyl monomer (A) has the following formula in the molecule: A monomer containing one glycidyl group represented by the formula and one ethylenically unsaturated bond (C═C) is used, and examples thereof include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and the like. In this specification, it should be understood that the term "vinyl monomer" is not used in a narrow sense (a monomer having _CH2 =CH-) but in a broad sense as described above.

In addition, as "hydroxyl group-containing vinyl monomer",
Vinyl monomers containing at least one hydroxyl group (OH) and usually one ethylenically unsaturated bond in the molecule, especially one hydroxyl group in the ester residue of acrylic ester or methacrylic ester. and containing 2 to 24, preferably 2 to 8 carbon atoms, among which those having the following formula (I) or () In each of the above formulas, R ₁ represents a hydrogen atom or a methyl group, n is an integer of 2 to 8, p and q are each an integer of 0 to 8, provided that the sum of p and q is 8
Hydroxyl group-containing (meth)acrylic acid esters of the type shown below, which do not exceed , are preferred.

Specific examples of such hydroxyl group-containing (meth)acrylic esters include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, and polypropylene glycol monoacrylate. , polypropylene glycol monomethacrylate, and the like.

"Drying oil fatty acid" and "semi-drying oil fatty acid" used to react with the glycidyl group-containing vinyl monomer or hydroxyl group-containing vinyl monomer to form the fatty acid-modified vinyl monomer (A). are unsaturated aliphatic carboxylic acids and their derivatives that are mainly collected from plant fruits, seeds, etc. here,
Although drying oil fatty acids cannot be strictly defined, they generally refer to unsaturated fatty acids with an iodine value of 130 or more, and semi-drying oil fatty acids have an iodine value of 100 to 130.
unsaturated fatty acids. Therefore, typical drying oil fatty acids and semi-drying oil fatty acids that can be used in the present invention include, for example, safflower oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, sesame oil fatty acid,
Non-conjugated double bond containing fatty acids such as poppy oil fatty acids, eno oil fatty acids, hempseed oil fatty acids, grape kernel oil fatty acids, corn oil fatty acids, tall oil fatty acids, sunflower oil fatty acids, cottonseed oil fatty acids, walnut oil fatty acids, rubber seed oil fatty acids, etc. Examples include saturated fatty acids, and these fatty acids can be used alone or in a mixture of two or more.

Furthermore, in the present invention, in addition to the above-mentioned unsaturated fatty acids containing non-conjugated double bonds, tung oil fatty acids, oiticica oil fatty acids, dehydrated castor oil fatty acids,
An unsaturated fatty acid having a conjugated double bond such as a high diene fatty acid can also be used alone as long as gelation does not occur during the copolymerization reaction described below, or an unsaturated fatty acid having a non-conjugated double bond type as described above can be used alone. It can also be used in combination with

The fatty acid-modified vinyl monomer (A) is prepared first in the absence of a solvent or in an appropriate inert solvent, although it differs depending on the type of unsaturated fatty acid used when using a glycidyl group-containing vinyl monomer. Inside,
It is carried out by addition-reacting both components at a reaction temperature of 60 to 220°C, preferably 120 to 170°C, and a reaction time of 0.5 to 40 hours, preferably 3 to 10 hours, and in the quantitative ratios described below. be able to.
The addition reaction product obtained by this reaction has a hydroxyl group newly generated by ring opening of the glycidyl group, but this hydroxyl group may be further esterified with an unsaturated fatty acid if necessary. The conditions for this esterification reaction are the same as those for esterification of a hydroxyl group-containing vinyl monomer described below.

Next, when using a hydroxyl group-containing vinyl monomer, the above-mentioned unsaturated fatty acid is usually reacted with the hydroxyl group-containing vinyl monomer in an appropriate inert solvent in the presence of an esterification catalyst. This can be done by The reaction generally takes about 100 to about 180
C, preferably about 120 to about 160 C, and the reaction time is generally about 0.5 to about 9 hours.
Usually about 1 to about 6 hours.

The glycidyl group-containing vinyl monomer or the hydroxyl group-containing vinyl monomer usually contains the unsaturated fatty acid 1
It can be used in a proportion of 0.5 to 1.9 mol per mol, preferably 1.0 to 1.9 mol per mol of said unsaturated fatty acid.
It is advantageous to use a proportion of 1.5 mol.

Examples of the esterification catalyst used in the above reaction include sulfuric acid, aluminum sulfate, potassium hydrogen sulfate, p-toluenesulfonic acid, hydrochloric acid, methyl sulfate, and phosphoric acid. About 0.001 to about 2.0% by weight of the total amount of the above unsaturated fatty acid and the glycidyl group-containing vinyl monomer or the hydroxyl group-containing vinyl monomer,
Preferably, it is used in a proportion of about 0.05 to about 1.0% by weight.

In addition, as the inert catalyst used if necessary, a water-immiscible organic solvent that can be refluxed at a temperature of 180°C or lower is preferable, such as aromatic hydrocarbons such as benzene, toluene, and xylene; heptane, Examples include fatty acid hydrocarbons such as hexane and octane.

Furthermore, when carrying out the above reaction, a polymerization inhibitor such as hydroquinone, ditertiary butylhydroxytoluene,
Methoxyphenol, tert-butylcatechol,
It is advantageous to add benzoquinone or the like to suppress the polymerization of the glycidyl group-containing vinyl monomer, the hydroxyl group-containing vinyl monomer, and/or the resulting fatty acid-modified vinyl monomer.

In the above reaction, there is an addition reaction between the glycidyl group of the glycidyl group-containing vinyl monomer and the carboxyl group of the unsaturated fatty acid, or an addition reaction between the hydroxyl group of the hydroxyl group-containing vinyl monomer and the carboxyl group of the unsaturated fatty acid. A condensation reaction takes place and a vinyl monomer modified with an unsaturated fatty acid having an acid value of generally 15 or less, preferably in the range of 1 to 10, is obtained.

Therefore, the fatty acid-modified acrylic monomer (A) used in the present invention can essentially consist of the unsaturated fatty acid obtained as described above introduced by addition reaction or condensation reaction. hand,
It may contain a small amount of unreacted unsaturated fatty acids or glycidyl group- or hydroxyl group-containing vinyl monomers, but the amount of unreacted unsaturated fatty acids is 40% of the total amount of monomer (A). % by weight or less, preferably 10
The content of glycidyl group-containing vinyl monomers or hydroxyl group-containing vinyl monomers should be limited to 37% by weight or less, preferably 25% by weight or less.

Next, isocyanate-modified acrylic monomer (B)
is obtained by reacting a hydroxyl group-containing acrylic monomer and/or an amino group-containing acrylic monomer with an isocyanate compound. It has a structure introduced at a position isolated from binding.

The "hydroxyl group-containing acrylic monomer" used to form the isocyanate-modified acrylic monomer (B) includes the formula (I) described above in preparing the fatty acid-modified vinyl monomer (A). )as well as()
Hydroxyl group-containing (meth)acrylic acid esters of the type shown are suitable.

Furthermore, the "amino group-containing acrylic monomer" has at least one, preferably only one, and 2 to 24, preferably 3 monomers in the ester residue component of the acrylic ester or methacrylic ester. Includes those containing ~15 carbon atoms, among others the following formula () In the above formula, R ₁ represents a hydrogen atom or a methyl group, R ₃ represents an alkyl group having 1 to 6 carbon atoms, and m is an integer of 1 to 6. Monoalkylaminoalkyl esters of acids are preferred.

Specific examples of such amino group-containing acrylic monomers include methylaminoethyl acrylate, methylaminoethyl methacrylate, ethylaminoethyl acrylate, ethylaminoethyl methacrylate, methylaminopropyl acrylate, and methylaminopropyl methacrylate.

An isocyanate compound that reacts with the hydroxyl group-containing acrylic monomer and/or amino group-containing acrylic monomer to form an isocyanate-modified acrylic monomer (B) containing a urethane bond or urea bond in the molecule. Any type of monoisocyanate compound or diisocyanate compound commonly used in the production of polyurethane can be used, such as aliphatic type, alicyclic type, aromatic type, aromatic-aliphatic type, etc., but generally, Approximately 50 to approx.
600, preferably in the range from about 50 to about 300, are advantageously used.

Specific examples of such monoisocyanate compounds include the following.

Methyl isocyanate, ethyl isocyanate, isopropyl isocyanate, isobutyl isocyanate, octadecyl isocyanate, phenyl isocyanate, α-naphthyl isocyanate, β-naphthyl isocyanate, etc.

Moreover, the following can be mentioned as a specific example of a diisocyanate compound.

OCN( _-CH2 ) _-a NCO(a=2-12), OCN- _{CH2- CH2} -S- _CH2 - _CH2- NCO, Lysine diisocyanate, isophorone diisocyanate, etc.

These monoisocyanate compounds or diisocyanate compounds can be used alone, or in combination of two or more.

Among the above isocyanate compounds, those having excellent yellowing resistance include aliphatic monoisocyanates such as methyl isocyanate, ethyl isocyanate, isopropyl isocyanate, isobutyl isocyanate, and octadecyl isocyanate;
and 1,6-hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-
Diisocyanate, xylene diisocyanate,
Examples include hydrogenated toluene diisocyanate.

When a diisocyanate compound is used among the above-mentioned isocyanate compounds, it is advantageous to partially block the diisocyanate compound with a blocking agent in advance and use it in the form of a compound having one free isocyanate group. As the blocking agent, monohydric alcohols or primary or secondary alkyl monoamines having a molecular weight of about 300 or less, preferably about 150 or less are used.

Examples of such alcohols include aliphatic alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, t-butyl alcohol, octyl alcohol, lauryl alcohol, stearyl alcohol, and oleyl alcohol; cyclopentanol, cyclo Alicyclic alcohols such as hexanol; phenyl carbinol,
Aromatic alkyl alcohols such as methylphenyl carbinol; cellosolve compounds such as methyl cellosolve, ethyl cellosolve, butyl cellosolve; methyl carbitol, ethyl carbitol,
Examples include carbitol-based compounds such as butyl carbitol.

Examples of primary or secondary alkyl monoamines include methylamine, ethylamine, butylamine, octylamine, stearylamine, dimethylamine, diethylamine, dibutylamine, and methylethylamine.

The isocyanate-modified acrylic monomer (B) is prepared by combining the hydroxyl group-containing acrylic monomer and/or amino group-containing acrylic monomer and the above isocyanate compound in an appropriate inert solvent, This can be carried out by reacting in a conventional manner. Since the reaction is generally exothermic, it is preferable to carry out the monomer dropwise into the isocyanate compound. The reaction is generally carried out at a temperature within the range of about 20 to 150°C, preferably as low as possible within this temperature range, using a commonly known reaction catalyst and polymerization inhibitor, and the reaction time is generally about 30 minutes. ~ Approximately 40 hours.

When the isocyanate compound used in the above reaction is a diisocyanate compound, a method is employed in which the diisocyanate compound is reacted with the above monomer in advance and then unreacted free isocyanate groups are blocked with a blocking agent as described above, or the diisocyanate compound is reacted in advance with the above monomer. Any method of partially blocking with a blocking agent and then reacting with the monomer described above may be used. The reaction between the diisocyanate compound and the blocking agent can be carried out under the same reaction conditions as described above for the preparation of the isocyanate-modified acrylic monomer.

The hydroxyl group-containing acrylic monomer and/or amino group-containing acrylic monomer is usually advantageously used in a proportion of 0.5 to 3 moles, preferably 1 to 2 moles, per mole of the isocyanate compound. be.

Furthermore, in the above reaction, it is advantageous to use a polymerization inhibitor used in the preparation of fatty acid-modified vinyl monomers, if necessary.

The "α,β-ethylenically unsaturated carboxylic acid" (c) used in the present invention is a type having an addition-polymerizable double bond between the carbon atom to which a carboxyl group is bonded and the carbon atom adjacent to it. Unsaturated aliphatic monomer or polycarboxylic acid with 3 carbon atoms
Those containing ~8, especially 3 to 5 carboxyl groups and 1 or 2 carboxyl groups are suitable, especially those having the following general formula () In the formula, R ₄ represents a hydrogen atom or a lower alkyl group, R ₅ represents a hydrogen atom, a lower alkyl group, or a carboxyl group, and R ₆ represents a hydrogen atom, a lower alkyl group, or a carboxy lower alkyl group. things are included. In the above formula (), the lower alkyl group is preferably one having 4 or less carbon atoms, particularly a methyl group.

Examples of such α,β-ethylenically unsaturated carboxylic acids include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, monoalkyl fumarate (C _1-8 ) maleate, and the like. These can be used alone or in combination of two or more.

Furthermore, the "unsaturated monomer" (D) that can be radically copolymerized with the above monomers (A), (B) and/or (C) includes a radically polymerizable ethylenically unsaturated bond (
As long as it has C=C), there are no particular restrictions, and it can be selected from a wide range depending on the desired performance of the aqueous coating composition as a final product. Representative examples of such unsaturated monomers are as follows.

(a) Esters of acrylic acid or methacrylic acid, such as methyl acrylate, ethyl acrylate,
Propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate,
C1 _~ of acrylic acid or methacrylic acid such as octyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, etc. ₁₈
Alkyl ester; glycidyl acrylate,
Glycidyl methacrylate; alkoxyalkyl esters of acrylic acid or methacrylic acid such as methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxybutyl acrylate, and ethoxybutyl methacrylate; allyl acrylate, allyl methacrylate, etc. Alkenyl esters of acrylic acid or methacrylic acid; _C2-8 hydroxyalkyl esters of acrylic acid or methacrylic acid, such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate; diethylaminoethyl acrylate, diethylaminoethyl methacrylate, methyl Mono- or di-alkylaminoalkyl esters of acrylic acid or methacrylic acid such as aminoethyl acrylate and methylaminoethyl methacrylate; alkenyloxyalkyl esters of acrylic acid or methacrylic acid such as allyloxyethyl acrylate and allyloxymethacrylate.

(b) Vinyl aromatic compounds: e.g. styrene, α
-Methylstyrene, vinyltoluene, p-chlorostyrene, vinylpyridine.

(c) Polyolefin compounds: for example, butadiene, isoprene, chloroprene.

(d) Amides of acrylic or methacrylic acid: for example acrylamide, N-methylolacrylamide, N-butoxymethylacrylamide.

(e) Others: acrylonitrile, methacrylonitrile, methyl isopropenyl ketone, vinyl acetate, vinyl esters (vinyl esters of aliphatic or aromatic monobasic acids or polybasic acids), beoba monomer, dialkyl maleate (C _{1 - 8} ) Esther etc.

These unsaturated monomers are appropriately selected depending on the desired physical properties, and may be used alone or in combination of two or more.

According to the present invention, the above fatty acid-modified vinyl monomer (A), isocyanate-modified acrylic monomer
(B), the α,β-ethylenically unsaturated carboxylic acid (C) and the unsaturated monomer (D) are copolymerized with each other. The copolymerization is carried out according to methods known per se for producing acrylic copolymers, such as solution polymerization,
This can be carried out using an emulsion polymerization method, a suspension polymerization method, or the like.

The blending ratio of the above four components in the case of copolymerization can be changed depending on the desired performance of the final oxidation-curable aqueous coating composition, but the following is based on the total weight of the above four components: It is appropriate to mix them in the following proportions.

Fatty acid-modified acrylic monomer (A): 5-80% by weight, preferably 15-70% by weight; Isocyanate-modified acrylic monomer (B): 3-80% by weight
60% by weight, preferably 5 to 40% by weight; α,β-ethylenically unsaturated carboxylic acid (C): 3 to
40% by weight, preferably 5-20% by weight; Unsaturated monomer (D): 0-89% by weight, preferably 20
~70% by weight.

The above copolymerization reaction is preferably carried out according to a solution polymerization method, in which the above four components are mixed in a suitable inert solvent in the presence of a polymerization catalyst, usually at about 0 to about 180°C, preferably. at a reaction temperature of about 40 to about 170°C for about 1 to about 20 hours, preferably about 4 to about 20 hours.
This can be carried out by continuing the reaction for about 10 hours.

As the solvent used, it is desirable to use a solvent that can dissolve the copolymer to be produced and is miscible with water so that gelation does not occur during the copolymerization reaction. Examples of such solvents that can be used include cellosolve solvents, carbitol solvents, glyme solvents, cellosolve acetate solvents, and alcohol solvents.

Examples of polymerization catalysts include azo compounds, peroxide compounds, sulfides, sulfin compounds, sulfin acids, diazo compounds, nitroso compounds, redox compounds, and radical initiators for normal radical polymerization such as ionizing radiation. is used.

It is generally advantageous to carry out the copolymerization reaction until the number average molecular weight of the resulting copolymer is within the range of about 500 to about 80,000, preferably about 1,000 to about 50,000.

The copolymer resin thus produced is usually 20
It has an acid value in the range of ~250, preferably 30-150, and is made water-soluble or water-dispersible as it is or after distilling off the solvent. This water solubility or water dispersibility can be achieved by a conventional method, for example, by neutralizing the carboxyl groups present in the copolymer resin with a conventionally known neutralizing agent. Examples of neutralizing agents that can be used include ammonia, amines,
Examples include alkali metal hydroxides, alkali metal carbonates or bicarbonates. The amine is a primary, secondary or tertiary alkyl amine;
Primary, secondary or tertiary alkanolamines; and cycloalkylamines can be used. In addition, hydroxides of alkali metals include potassium hydroxide and sodium hydroxide; carbonates and bicarbonates of alkali metals include potassium carbonate,
Sodium carbonate, sodium bicarbonate, etc. can be used.

The neutralization treatment can be easily carried out by a conventional method by adding the neutralizing agent or an aqueous solution thereof to the copolymer resin or its solution obtained as described above. The amount of neutralizing agent used is generally 0.1 to 2.0 equivalents, preferably 0.3 to 2.0 equivalents based on the carboxyl group in the resin.
It is 1.0 equivalent.

The resin thus made water-soluble or water-dispersible can be used as it is as a film-forming component in the oxidation-curable aqueous coating composition of the present invention.

In addition, the oxidation-curable aqueous coating composition of the present invention may optionally contain extender pigments, coloring pigments, driers such as cobalt naphthenate, lead naphthenate, rust preventives, ultraviolet absorbers, surfactants, etc. Additives such as preservatives can be included. The drying properties of the coating can be significantly accelerated by the addition of a dryer.

The oxidation-curable aqueous coating composition of the present invention described above has excellent storage stability over a long period of time, and the coating film obtained from it is non-tacky and has an excellent texture. ing. Furthermore, coating compositions having various properties can be obtained by appropriately selecting the polymerizable unsaturated monomer (D) to be copolymerized within a wide range.

The oxidation-curing aqueous coating composition of the present invention can be diluted with water if necessary, and the coating film formed from the coating composition is sufficiently cured even at room temperature, but of course it is not necessary to dilute it with water. It may be cured while heating depending on the conditions.

Therefore, since the oxidation-curable aqueous coating composition of the present invention fully cures at room temperature, it can be used as a general-purpose paint, and since it can be heat-cured, it is also useful as an industrial paint. It is.

Furthermore, the oxidation-curable aqueous coating composition of the present invention can be used in combination with other emulsion compositions, and can also be used as a dispersion stabilizer in emulsion polymerization.

Next, the present invention will be further explained by examples. In the examples, "parts" and "%" indicate "parts by weight" and "% by weight" unless otherwise specified.

Example 1 (1-a) The following components: Linseed oil fatty acid 2240 parts Hydroquinone 1.2 parts Methyl sulfate 2.5 parts Heptane 144 parts were placed in a reaction vessel and heated to 150°C while stirring. Next, a mixture of the following components: 1300 parts of hydroxyethyl methacrylate, 7.6 parts of methyl sulfuric acid, 2.6 parts of hydroquinone, and 234 parts of toluene was added dropwise into a reaction vessel at 150° C. over a period of 2 hours. The resulting condensed water was removed from the reaction system, and the reaction was continued for 7 hours after the dropwise addition was completed. After the reaction, the solvent was removed to obtain a fatty acid-modified acrylic monomer having an acid value of 6.1 and a Gardner viscosity of A.

(1-b) 777 parts of isophorone diisocyanate was placed in a reaction vessel and heated to 6.0°C. A solution prepared by dissolving 0.24 parts of ditertiarybutylhydroxytoluene in 45 parts of hydroxyethyl methacrylate was added dropwise to this solution over 2 hours, and after the addition was completed, it was left at 80°C for 2 hours. Then add n to this solution
-311 parts of butanol was added and the mixture was left at 80°C for 2 hours, and then left at room temperature overnight to remove excess n-butanol. In this way, an isocyanate-modified acrylic monomer was obtained.

(1-c) 600 parts of n-butyl cellosolve was placed in a reaction vessel and heated to 120°C. A mixture in the proportions shown below was then added dropwise to this solution over a period of 2 hours.

Fatty acid-modified acrylic monomer obtained in (1-a) above 252 parts Isocyanate-modified acrylic monomer obtained in (1-b) above 150 parts n-Butyl methacrylate 106 parts Methacrylic acid 92 parts Azobisdimethylvalero Nitrile 30 parts The reaction temperature was maintained at 120°C, and the above mixture was added dropwise to the reaction solution while stirring. 6 parts of azobisisobutyronitrile were added 1 hour and 2 hours after the completion of the dropwise addition, and the mixture was allowed to stand at the same temperature for 2 hours to carry out a reaction. After the reaction was completed, unreacted monomers and n-butyl cellosolve were distilled under reduced pressure to reduce the heating residue to 78.5%. Thus, the resin acid value
A copolymer with a Gardner viscosity of 89.2 and a Gardner viscosity (60% n-butyl cellosolve solution) U to V was obtained.

47 PHR of n-butyl cellosolve was added to the obtained copolymer, and then equivalence neutralized using 28% aqueous ammonia to obtain a 47% aqueous solution. Cobalt naphthenate is added to this copolymer aqueous solution as a dryer.
Manganese naphthenate and lead naphthenate were mixed in metal amounts of 0.07%, 0.07% and 0.2%, respectively, and dispersed with a paint conditioner to prepare an aqueous coating composition.

Applying the obtained aqueous coating composition to a mild steel plate,
It was dried for 10 days at room temperature. The resulting paint film had a pencil hardness of B, an elixirne value of 3 mm, and a paint film with no tackiness and a good texture.

In addition, when the paint film is dried by baking at 100℃ for 30 minutes, the pencil hardness is 4B and the Erichsen value is 2mm.
No tackiness was observed on the surface of the coating film.

Example 2 (2-a) 777 parts of isophorone diisocyanate was placed in a reaction vessel and heated to 60°C. A solution prepared by dissolving 0.24 parts of ditertiarybutylhydroxytoluene in 455 parts of hydroxyethyl methacrylate was added dropwise to this solution over 2 hours, and after the addition was completed, it was left at 80°C for 2 hours. Then add this solution to 30
Cool to ℃ and add n-butylamine to this.
Drip 255.5 parts over 2 hours or more. During this time, the temperature of the contents rises to 50°C due to exotherm.
Further, the mixture was left at the same temperature for 1 hour and then at room temperature for 1 day to obtain an isocyanate-modified acrylic monomer.

(2-b) 600 parts of n-butyl cellosolve was placed in a reaction vessel and heated to 130°C. A mixture in the proportions shown below was then added dropwise to this solution over a period of 2 hours.

Fatty acid-modified acrylic monomer obtained in (1-a) of Example 1 252 parts Isocyanate-modified acrylic monomer obtained in (2-a) above 150 parts Styrene 53 parts Methyl methacrylate 53 parts Methacrylic acid 92 parts Azobisdimethylvaleronitrile 30 parts The reaction temperature was maintained at 130°C, and the above mixture was added dropwise to the reaction solution while stirring. 6 parts of azobisisobutyronitrile were added 1 hour and 2 hours after the completion of the dropwise addition, and the mixture was allowed to stand at the same temperature for 2 hours to carry out the reaction. After the reaction was completed, unreacted monomers and n-butyl cellosolve were distilled under reduced pressure to reduce the heating residue to 82.1%. A copolymer having a resin acid value of 70 was thus obtained.

The obtained copolymer was neutralized in the same manner as in Example 1 to make it water-soluble, and a similar dryer was added to prepare an aqueous coating composition.

Applying the obtained aqueous coating composition to a mild steel plate,
It was dried for 10 days at room temperature. The resulting paint film had a pencil hardness of HB, an elixirne value of 1 mm, and a paint film with no tackiness and a good texture.

In addition, when the paint film is dried by baking at 100℃ for 30 minutes, the pencil hardness is F and the Erichsen value is 1mm.
No tackiness was observed on the surface of the coating film.

Example 3 (3-a) Put 650 parts of hydroxyethyl methacrylate and 0.15 parts of hydroquinone into a reaction vessel,
It was heated to 80°C. 495 parts of n-butyl isocyanate was added dropwise to this solution over 1.5 hours.
After the dropwise addition was completed, the mixture was left at 90°C for 2 hours. In this way, a butyl isocyanate-modified acrylic monomer was obtained.

(3-b) 400 parts of n-butyl cellosolve was placed in a reaction vessel and heated to 120°C. A mixture in the proportions shown below was then added dropwise to this solution over a period of 2 hours.

Fatty acid-modified acrylic monomer obtained in (1-a) of Example 1 280 parts Isocyanate-modified acrylic monomer obtained in (3-a) above 100 parts Styrene 100 parts Methyl methacrylate 56 parts Methacrylic acid 92 parts Azobisdimethylvaleronitrile 30 parts The reaction temperature was maintained at 120°C, and the above mixture was added dropwise to the reaction solution while stirring. 6 parts of azobisisobutyronitrile were added 1 hour and 2 hours after the completion of the dropwise addition, and the mixture was allowed to stand at the same temperature for 2 hours to carry out a reaction. After the reaction was completed, unreacted monomers and n-butyl cellosolve were distilled under reduced pressure to reduce the heating residue to 82.5%. A copolymer having a resin acid value of 87 was thus obtained. The obtained copolymer was neutralized in the same manner as in Example 1 to make it water-soluble, and a similar dryer was added to prepare an aqueous coating composition.

Applying the obtained aqueous coating composition to a mild steel plate,
It was dried for 10 days at room temperature. The resulting coating film had a pencil hardness of B, an elixirne value of 1 mm, and a coating film with no tackiness and a good texture.

Furthermore, when the paint film is dried by baking at 100℃ for 30 minutes, the pencil hardness is 4B and the Erichsen value is 1mm.
The surface of the coating film was not sticky and felt very nice to the touch.

Claims (1)

[Scope of Claims] 1 (A) An acrylic monomer selected from glycidyl group-containing vinyl monomers and hydroxyl group-containing vinyl monomers, and an unsaturated fatty acid selected from drying oil fatty acids and semi-drying oil fatty acids. (B) an acrylic monomer selected from hydroxyl group-containing acrylic monomers and amino group-containing acrylic monomers, and an isocyanate compound; An isocyanate-modified acrylic monomer consisting of the reaction product of; (C) an α,β-ethylenically unsaturated carboxylic acid; An oxidation-curable aqueous coating composition comprising a water-soluble or water-dispersible resin obtained by copolymerizing a radically copolymerizable unsaturated monomer.