JP2002012823A - Aqueous coating material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous coating material excellent in weather resistance and stability. SOLUTION: A coating material composition containing an aqueous emulsion (A), a crosslinking agent (B) and a bisbenzotriazolephenol compound (C) expressed by general formula (1) [wherein, A is an alkylene, O, NH, S, SO or SO2; n is 0 or 1; R1 and R2 are the same as or different from each other, and they are each hydroxy, a 1-12C normal or branched hydroxyalkyl, a radical- polymerizing unsaturated group or a (meth)acrylic group; R3 and R4 are the same as or different from each other, and they are each H, a 1-4C alkyl, a 1-4C alkoxyl, an aryl or a halogen atom].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an aqueous coating composition capable of forming a coating film having excellent weather resistance.

[0002]

2. Description of the Related Art Recently, organic solvent-based paints using an organic solvent as a diluent have been required to regulate the use of organic solvents in terms of pollution, the amount of organic solvents used in terms of health, the working environment and the saving of resources. Tend to reduce. For this reason,
Aqueous paints using water as a diluent have attracted attention, and the performance requirements for aqueous paints have been increasing accordingly. Here, the water-based paint used as a top-coat paint on an object to be coated is, in particular, an automobile body having a strong overseas ultraviolet ray region (for example, California and Oceania).
When the vehicle travels, it is exposed to sunlight for a long period of time due to its use, and therefore, components in the coating film are deteriorated particularly by ultraviolet rays, so that the top coating film is broken, discolored, and discolored. In order to prevent this, an ultraviolet absorber is particularly added to the topcoat composition.

[0003] Examples thereof include cyanoacrylates, piperidinyls, benzophenones, and benzotriazoles. However, the weather resistance of the coating film due to these UV absorbers is insufficient. In particular, in order to improve the weather resistance under severe conditions such as the above-mentioned automotive top coating, a large amount of the UV absorber is added to the coating. Must.

[0004] However, in a topcoat paint in which the color is important, if a large amount of an ultraviolet absorber is added, the reflection of sunlight is changed, so that coloring is observed and the color of the topcoat film is affected, or There has been a problem that cracks easily occur on the surface of the coating film.

[0005] Further, since the above-mentioned ultraviolet absorbers are not so good in compatibility with the resin in the coating film, they are easily eluted from the coating film by rainwater, washing, wax, etc. with the passage of time, and cannot maintain the weather resistance for a long period of time. There were also problems.

[0006]

Means for Solving the Problems Therefore, the present inventors have
As a result of intensive studies to solve the above problems, the addition of a bisbenzotriazole phenol-based compound to an aqueous paint allows the functional group in the bisbenzotriazole phenol-based compound and the aqueous emulsion in the aqueous paint, It was found that the functional group reacted to find that the compound was retained in the coating film and could exhibit excellent weather resistance for a long period of time, thereby completing the present invention. That is, the present invention provides: Aqueous emulsion (A) and bisbenzotriazole phenolic compound (C) represented by general formula (1)
An aqueous coating composition comprising

[0007]

Embedded image General formula (1)(Where A is an alkylene group, -O-, -NH-, -S
-, -SO-, or -SO _Two-Indicates that n is 0 or 1
is there. R₁And R_TwoAre the same or different, and
Linear or branched hydroxyal having a prime number of 1 to 12
Kill group, radical polymerizable unsaturated group, (meth) acryloy
Represents a hydroxyl group. Also R_ThreeAnd R_Four Are the same or different, water
Elemental atom, alkyl group having 1 to 4 carbon atoms, 1 to 4 carbon atoms
Represents an alkoxy group, an aryl group or a halogen atom.
You. ) 2. 4. The method according to item 1, further comprising a crosslinking agent (B).
2. an aqueous coating composition; When the crosslinking agent (B) is a blocked isocyanate compound,
3. The aqueous coating composition according to item 2, which is any one of a mino resin
Thing, 4. Bisbenzotriazole phenol for crosslinking agent (B)
The aqueous compound (C) is added to the aqueous emulsion (A).
The aqueous coating composition according to item 2 or 3,
You.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the present invention, the aqueous emulsion (A) is a film-forming component, and conventionally known water-dispersible resins can be used without any particular limitation. Usually, one or more radical polymerizable unsaturated monomers are used. It is a copolymer emulsion obtained by emulsion polymerization in the presence of an emulsifier (d) and a catalyst. Examples of the radical polymerizable unsaturated monomer include an acidic group-containing radical polymerizable unsaturated monomer (a), a hydroxyl group-containing radical polymerizable unsaturated monomer (b), and other radical polymerizable unsaturated monomers. (C) and the like, and the emulsion polymerization reaction can be performed by any method such as a monomer dropping method, a monomer batch charging method, and a pre-emulsion method.

The above-mentioned acidic group-containing radically polymerizable unsaturated monomer (a) imparts water solubility to the obtained copolymer, and examples of the acidic group include a carboxyl group and a sulfonic acid group. Can be Examples of the radical polymerizable unsaturated monomer having a carboxyl group include, for example, acrylic acid, methacrylic acid, crotonic acid, ethacrylic acid, propyl acrylic acid, isopropyl acrylic acid, itaconic acid, and the like, having a sulfonic acid group. These include sulfoethyl methacrylate and its sodium and ammonium salts. In addition, it is preferable that some acidic groups of the acidic group-containing radically polymerizable unsaturated monomer are sulfonic acid groups. It is considered that the sulfonic acid group has a curing acceleration effect.

Examples of the hydroxyl group-containing radically polymerizable unsaturated monomer (b) include, for example, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate , Allyl alcohol and the like. Further, as other radically polymerizable unsaturated monomers (c), for example,
Methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, lauryl acrylate, etc., alkyl acrylates, itaconic esters, Maleic esters such as dimethyl maleate; fumaric esters such as dimethyl fumarate; methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate;
Alkyl methacrylates such as n-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, stearyl methacrylate, dodecyl methacrylate; acrylic acid Benzyl, benzyl methacrylate, styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, p-tert-butylstyrene;
Isobornyl acrylate, isobornyl methacrylate,
Cyclohexyl acrylate, cyclohexyl methacrylate, acrylonitrile, methacrylonitrile, vinyl acetate, etc., ethylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, divinylbenzene, allyl (meth) Polyvinyl compounds having a plurality of reactive double bonds such as acrylate; silane compounds such as trialkoxyvinylsilane and γ-methacryloyloxyalkyl trialkoxysilane; and the like. These compounds may be used alone or in combination of two or more. it can.

The above-mentioned acidic group-containing radically polymerizable unsaturated monomer (a), hydroxyl group-containing radically polymerizable unsaturated monomer (b) and other radically polymerizable unsaturated monomer (c)
Is used, the content of the acidic group-containing radically polymerizable unsaturated monomer (a) is 0.1 to 10% by weight, preferably 0.5 to 5% by weight.
% By weight, hydroxyl-containing radically polymerizable unsaturated monomer (b)
Is in the range of 0.5 to 30% by weight, preferably 5 to 20% by weight,
Other radically unsaturated monomers (c) may have a content of 60 to 99.
The range is preferably 4% by weight, more preferably 75 to 94.5% by weight. Radical polymerizable unsaturated monomer containing acidic group (a)
If the content is less than 0.1% by weight, the crosslinking property with the compound (C) becomes poor, and if it exceeds 10% by weight, the stability of the aqueous emulsion (A) is unpreferably decreased.

When the content of the hydroxyl group-containing radically polymerizable unsaturated monomer (b) is less than 0.5% by weight, the crosslinking property with the compound (C) becomes poor, and when it exceeds 30% by weight, the aqueous emulsion (A) Is not preferred because the stability of
Further, when the content of the other radically polymerizable unsaturated monomer (c) is less than 60% by weight, the weather resistance becomes poor, and 99.4%.
Exceeding the weight% is not preferred because the stability of the aqueous emulsion (A) is reduced.

The emulsifier (d) used in the production of the aqueous emulsion (A) includes an anionic emulsifier, a nonionic emulsifier, a zwitterionic emulsifier and the like. Examples of the anionic emulsifier include dodecylbenzenesulfonic acid, alkyl sulfate, alkylbenzene sulfonate, alkyl phosphate, monoalkyl sodium succinate, sodium dialkyl sulfosuccinate, and the like.

Examples of the nonionic emulsifier include polyoxyethylene alkyl ethers, polyoxyethylene derivatives, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylamines, and alkyl alkanolamides. No. For example, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether,
Polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether polyoxyethylene phenol ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene mono Oleate, sorbitan monolaurate, sorbitan monostearate,
Sorbitan monostearate, sorbitan triolate, polyoxyethylene sorbitan monolaurate, polyoxyethylene octyl phenyl ether, and the like.

Examples of the amphoteric emulsifier include dimethylalkylbedines, dimethylalkyllaurylbedines, alkylglycines and the like. Further, an anion-nonionic emulsifier such as polyoxyethylene alkylphenyl ether sulfonate can be used.

The amount of the emulsifier (d) is 0.1% based on 100% by weight of the solid content of the aqueous emulsion (A).
The range is 5 to 10% by weight, preferably 1.0 to 5.0% by weight. If the amount is less than 0.5% by weight, the water-dispersibility of the aqueous emulsion (A) is reduced, and the stability is deteriorated. Also 10
Exceeding the weight percent is not preferred because the water resistance of the formed coating film is reduced. Examples of the catalyst used for producing the aqueous emulsion (A) include ammonium peroxo-2-sulfate.

In the present invention, the above-mentioned aqueous emulsion (A)
It may contain a crosslinking agent (B) capable of crosslinking with a functional group therein. Examples of the crosslinking agent (B) include a blocked isocyanate compound and an amino resin (melamine resin, benzoguanamine resin, urea resin, etc.), and a blocked isocyanate compound is preferred from the viewpoint of crosslinking and reactivity.

The blocked isocyanate compound used as the crosslinking agent (B) in the present invention is a compound obtained by blocking an aliphatic and / or alicyclic isocyanate compound with a blocking agent. The isocyanate compound is aliphatic and / or
Or, in the case of an isocyanate compound other than an alicyclic compound, for example, an aromatic isocyanate compound, it is not preferable because the weather resistance of the coating film is deteriorated.

Examples of the aliphatic and / or alicyclic isocyanate compound include aliphatic or alicyclic diisocyanate compounds such as isophorone diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, and methylene diisocyanate, and dimers thereof. , Trimers, and excess amounts of these isocyanate compounds in ethylene glycol, propylene glycol,
Examples of the compound include a terminal isocyanate-containing compound obtained by reacting a low-molecular-weight active hydrogen-containing compound such as trimethylolpropane, hexanetriol, or castor oil.

On the other hand, the blocking agent is one that blocks by adding to the isocyanate group of the isocyanate compound, and the blocked isocyanate compound formed by the addition is stable at room temperature and when heated to about 100 ° C. to 200 ° C. It is desirable that the isocyanate group can be regenerated by dissociating the blocking agent. Examples of the blocking agent satisfying such conditions include lactam compounds such as ε-caprolactam and γ-caprolactam; oxime compounds such as methyl ethyl ketoxime and cyclohexanone oxime; and aromatic alkyl compounds such as phenylcarbinol and methylphenylcarbinol. Alcohols; ether alcohol compounds such as ethylene glycol monobutyl ether;

In the present invention, the bisbenzotriazole phenolic compound (C) represented by the above general formula (1)
(Hereinafter, may be abbreviated as compound (C).) Works as an ultraviolet absorber and exerts an effect even when used alone. However, a functional group having good reactivity such as a hydroxyl group or a hydroxyalkyl group in the molecule. Therefore, they are easily chemically bonded to the functional groups in the aqueous emulsion (A) and the functional groups in the cross-linking agent (B), which will be described later. It can maintain the nature.

The alkylene group used in the portion [A] represented by the general formula (1) includes methylene, ethylene, 2-butylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, propylene, isopropylene, Ethylethylene, 1-methyltrimethylene, 2
Linear or branched ones such as -methyltrimethylene and 2,2-dimethyltrimethylene.

The hydroxyalkyl group corresponding to R ₁ and R ₂ in the compound (C) includes, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-
Butyl, tert-butyl, pentyl, n-hexyl,
C 1 -carbon such as n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, etc.
Examples include a group in which 1 to 3 hydroxyl groups are substituted at any position of the 12 linear or branched alkyl groups.

Specific examples include, but are not limited to,
For example, hydroxymethyl, 2-hydroxyethyl, 3
-Hydroxypropyl, 2,3-dihydroxypropyl, 4-hydroxybutyl, 1,1-dimethyl-2-hydroxyethyl, 5,5,4-trihydroxypentyl, 5-hydroxypentyl, 6-hydroxyhexyl, 1-hydroxy Isopropyl, 2-methyl-3-hydroxypropyl, 7-hydroxyheptyl, 8-hydroxyoctyl, 9-hydroxynonyl, 10-hydroxydecyl, 11-hydroxyundecyl, 12-hydroxydodecyl and the like can be mentioned. In the present invention,
Among them, a hydroxyalkyl group having 2 to 4 carbon atoms is particularly preferable.

The alkyl group having 1 to 4 carbon atoms corresponding to R ₃ and R ₄ in the compound (C) includes, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s
Examples thereof include linear or branched ones such as ec-butyl and tert-butyl.

Examples of the alkoxy group having 1 to 4 carbon atoms corresponding to R ₃ and R ₄ in the compound (C) include, for example, methoxy,
Examples thereof include linear or branched ones such as ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy and tert-butoxy.

The aryl group corresponding to R ₃ and R ₄ in the compound (C) is, for example, one having 1 to 4 carbon atoms on a phenyl ring.
Alkyl, alkoxy having 1 to 4 carbon atoms, phenyl and naphthyl which may have a halogen atom and the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.

Examples of the compound (C) include, for example, 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -1,4-dihydroxybenzene], 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4- (hydroxymethyl) phenol], 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4- (2-hydroxyethyl ) Phenol], 2,2'-methylenebis [6-
(5-chloro-2H-benzotriazol-2-yl)
-4- (2-hydroxyethyl) phenol], 2,
2'-methylenebis [6- (5-bromo-2H-benzotriazol-2-yl) -4- (2-hydroxyethyl) phenol], 2,2'-methylenebis [6- (2
H-benzotriazol-2-yl) -4- (3-hydroxypropyl) phenol], 2,2′-methylenebis [6- (5-chloro-2H-benzotriazole-2)
-Yl) -4- (3-hydroxypropyl) phenol], 2,2'-methylenebis [6- (5-bromo-2
H-benzotriazol-2-yl) -4- (3-hydroxypropyl) phenol], 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4
-(2-hydroxypropyl) phenol], 2,2 '
-Methylenebis [6- (5-chloro-2H-benzotriazol-2-yl) -4- (2-hydroxypropyl) phenol], 2,2'-methylenebis [6- (5
-Bromo-2H-benzotriazol-2-yl) -4
-(2-hydroxypropyl) phenol], 2,2 '
-Methylenebis [6- (2H-benzotriazole-2
-Yl) -4- (4-hydroxybutyl) phenol], 2,2'-methylenebis [6- (5-chloro-2
H-benzotriazol-2-yl) -4- (4-hydroxybutyl) phenol].

2'-methylenebis [6- (5-bromo-
2H-benzotriazol-2-yl) -4- (4-hydroxybutyl) phenol], 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4
-(5-hydroxyheptyl) phenol], 2,2 '
-Methylenebis [6- (2H-benzotriazole-2
-Yl) -4- (6-hydroxyhexyl) phenol] 1,1-bis {2- [6- (2H-benzotriazol-2-yl) -1-hydroxy-4- (2-hydroxyethyl) phenyl] {Propane, 2,2-bis} 2
-[6- (2H-benzotriazol-2-yl) -1
-Hydroxy-4- (2-hydroxyethyl) phenyl]} butane, bis {2- [6- (2H-benzotriazol-2-yl) -1-hydroxy-4- (2-hydroxyethyl) phenyl} ether, Screw ｛2- [6-
(2H-benzotriazol-2-yl) -1-hydroxy-4- (2-hydroxyethyl) phenyl} amine, bis {2- [6- (2H-benzotriazole-2)
-Yl) -1-hydroxy-4- (2-hydroxyethyl) phenyl} sulfide, bis {2- [6- (2H-
Benzotriazol-2-yl) -1-hydroxy-4
-(2-hydroxyethyl) phenyl} sulfoxide,
Bis {2- [6- (2H-benzotriazol-2-yl) -1-hydroxy-4- (2-hydroxyethyl)
2,2'-methylenebis [6-
(2H-benzotriazol-2-yl) -4- (meth) acryloyloxy-2-hydroxybenzene],
2,2′-methylenebis [6- (2H-benzotriazol-2-yl) -4-((meth) acryloyloxymethyl) phenol], 2,2′-methylenebis [6-
(2H-benzotriazol-2-yl) -4- (2-
(Meth) acryloyloxyethyl) phenol],
2,2′-methylenebis [6- (5-chloro-2H-benzotriazol-2-yl) -4- (2- (meth) acryloyloxyethyl) phenol], 2,2′-methylenebis [6- (5 -Bromo-2H-benzotriazol-2-yl) -4- (2- (meth) acryloyloxyethyl) phenol], 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4-
(3- (meth) acryloyloxypropyl) phenol], 2,2′-methylenebis [6- (5-chloro-2)
H-benzotriazol-2-yl) -4- (3- (meth) acryloyloxypropyl) phenol], 2,
2′-methylenebis [6- (5-bromo-2H-benzotriazol-2-yl) -4- (3- (meth) acryloyloxypropyl) phenol], 2,2′-methylenebis [6- (2H-benzo Triazol-2-yl) -4- (2- (meth) acryloyloxypropyl) phenol], 2,2'-methylenebis [6- (5
-Chloro-2H-benzotriazol-2-yl) -4
-(2- (meth) acryloyloxypropyl) phenol], 2,2′-methylenebis [6- (5-bromo-
2H-benzotriazol-2-yl) -4- (2-
(Meth) acryloyloxypropyl) phenol],
2,2′-methylenebis [6- (2H-benzotriazol-2-yl) -4- (4- (meth) acryloyloxybutyl) phenol], 2,2′-methylenebis [6- (5-chloro-2H -Benzotriazole-2-
Yl) -4- (4- (meth) acryloyloxybutyl) phenol], 2,2′-methylenebis [6- (5
-Bromo-2H-benzotriazol-2-yl) -4
-(4- (meth) acryloyloxybutyl) phenol], 3,3- [2,2'-bis [6- (2H-benzotriazol-2-yl) -1-hydroxy-4- (2
-(Meth) acryloyloxyethyl) phenyl]] propane, 2,2- [2,2'-bis [6- (2H-benzotriazol-2-yl) -1-hydroxy-4-
(2- (meth) acryloyloxyethyl) phenyl]] butane. These compounds (C)
Each may be used alone or two or more of them may be used in combination.

The compounding ratio of the compound (C) in the present invention is 0.5 to 50% by weight, preferably 1 to 100% by weight of the total amount of the solid content of the aqueous emulsion (A) and the crosslinking agent (B). It may be used in the range of ３０30% by weight. If the amount used is less than 0.5% by weight, there is no effect on improving the weather resistance of the formed coating film, and if it exceeds 50% by weight, the stability of the water-based paint is inferior.

Since the above compound (C) does not dissolve in water, its addition method is, for example, after adding it to the crosslinking agent (B), sufficiently stirring and dispersing it, and adding it to the aqueous emulsion (A). It is preferred to add. In addition, as a method for adding the compound (C), the aqueous emulsion (A) can be included in the emulsion particles by mixing the monomer mixture at the time of production of the aqueous emulsion (A) and performing emulsion polymerization. Further, as a method of adding the compound (C), it is also possible to add the compound (C) together with the pigment at the time of preparing the pigment-dispersed paste, and to enamelize the paste with the dispersion resin.

As the above-mentioned pigments, those conventionally used can be used without limitation, for example, coloring pigments such as titanium oxide, carbon black, red iron oxide, aluminum paste, pearl powder, graphite, MIO, phthalocyanine blue; And extenders such as mica, barita, talc, calcium carbonate, and silica; and other pigments include rust preventive pigments such as zinc phosphate and iron phosphate.

The composition of the present invention may further comprise, if necessary, paint additives such as a film-forming aid, a curing catalyst, an antifoaming agent, a thickener, an antifreezing agent, and conventionally known ultraviolet absorbers and light stabilizers. May be used together within a range that does not adversely affect the coating film performance.

[0033] The object to be coated with the composition of the present invention obtained as described above includes aluminum, steel, zinc, tin, and the like.
Metal coatings such as copper and stainless steel, zinc on steel surface
Plated metal base material coated with tin, chrome, etc.
Chemical conversion-treated metal-based coating materials whose surfaces such as iron and steel are treated with chromic acid, phosphoric acid, and the like, and coating materials obtained by subjecting these substrates to electrodeposition coating or intermediate coating.

The coating method can be applied to the surface of the object to be coated by means such as brush coating, spray spray coating, roller coating, dip coating, electrostatic powder coating, or electrodeposition coating. The amount of coating varies depending on the type of coating, coating means, purpose of use, and the like, but is generally about 1 to 500 μm, preferably about 10 to 80 μm. When the film thickness is less than 1 μm, there is no effect on the weather resistance, and when the film thickness exceeds 500 μm, the adhesion to an object to be coated is poor.

The conditions for the drying temperature and time of the coating film can be selected according to the type of the aqueous coating material. For example, an aqueous emulsion (A) comprising the above-mentioned monomer, a blocked polyisocyanate compound and a crosslinking agent (B) It is considered that about 20 minutes to 120 minutes at 80 ° C. to 150 ° C. is sufficient for the water-based paint contained as the above.

[0036]

According to the present invention, a coating film obtained from an aqueous coating composition obtained by adding a bisbenzotriazole phenolic compound (C) to an aqueous emulsion (A) is a conventional coating such as a benzophenone-based or cyanoacrylate-based coating. Weather resistance is improved as compared with the case where the ultraviolet absorbent is contained.

The reason for this is that the hydroxyalkyl group of the bisbenzotriazole phenolic compound (C) represented by the general formula (1) is a radically polymerizable unsaturated group in the aqueous emulsion (A) or a crosslinking agent (B). It is considered that the compound (C) is fixed in the coating film and contributes to the weather resistance of the coating film because the compound (C) is crosslinked with a functional group such as an isocyanate group.

[0038]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the embodiments. Note that “parts” and “%” indicate “parts by weight” and “% by weight”.

Production Example of Aqueous Emulsion (A) 300 parts of deionized water and 1 part of sodium dodecylbenzenesulfonate were charged into a 2 liter glass flask equipped with a stirrer, a thermometer and a condenser, and the air inside was charged. After replacing with nitrogen, the internal temperature was raised to 82 ° C. while stirring to dissolve. Next, 320 parts of deionized water, 50 parts of sodium dodecylbenzenesulfonate, and 2 parts of ammonium peroxo-2-sulfate are added to another container, and the mixture is well stirred and foamed, and a monomer mixture solution having the following composition is added and stirred to obtain an emulsion. And it was dropped continuously into the reaction vessel in 4 hours.

Styrene 275 parts n-butyl acrylate 170 parts 2-hydroxymethacrylate 50 parts acrylic acid 5 parts After the completion of the dropwise addition, the mixture is stirred at 82 ° C. for 2 hours, cooled to 40 ° C., and solid content concentration of 50% by weight aqueous emulsion. (A)
I got

Production Example of Aluminum Pigment Dispersion Paste 17 parts of aluminum pigment paste MG-51 (trade name, manufactured by Asahi Kasei Corporation, metal content: 66.3%) and 20 parts of butyro cellosolve are added to a container and mixed with stirring. Thereby, an aluminum pigment-dispersed paste having a solid content of 30% by weight was obtained.

Example 1 "Staphyloid WD-220" as a crosslinking agent (B)
(Trade name, HMDI-MEK oxime block product, manufactured by Takeda Pharmaceutical Co., Ltd.)
UVA-100 "(trade name, manufactured by Otsuka Chemical Co., Ltd., bisbenzotriazole phenolic compound, Chemical Formula 3) (1 part) was added, and the mixture was sufficiently stirred. Next, 120 parts of the aqueous emulsion (A) having a solid content of 50% by weight obtained above, 20 parts of the aluminum pigment dispersion paste having a solid content of 30% by weight obtained above, and 2 parts of dibutyltin dilaurate were obtained. , And deionized water, and the mixture was stirred with a disper. 1 was obtained.

[0043]

Embedded image

RUVA-100: 2,2'-methylenebis [6
-(2H-benzotriazol-2-yl) -4- (2-hydroxyethyl) phenol] Example 2 Except that in Example 1, 40 parts of isophorone diisocyanate-MEK oxime blocked compound was blended as the crosslinking agent (B). By the same operation as in Example 1, the solid content was 3
0% by weight aqueous paint NO. 2 was obtained.

Comparative Example 1 The compound (C) of Example 1 was referred to as "TINUVIN
-384 "(manufactured by Ciba-Geigy Co., trade name, benzotriazole-based ultraviolet absorber), except that 1 part of a solid content 30% by weight aqueous paint NO.
3 was obtained.

Comparative Example 2 The compound (C) of Example 1 was referred to as "TINUVIN
-123 "(Ciba-Geigy Co., trade name, piperidinyl-based ultraviolet absorber), except that 1 part of a solid content 30% by weight aqueous paint NO. 4 was obtained. Table 1 shows the content of the water-based paint.

[0047]

[Table 1]

Preparation of Coated Test Plate A cold-rolled dull steel plate was coated with 25 μm of an amine-modified epoxy resin cationic electrodeposition paint on a chemical conversion treatment Palbond # 3020 (trade name, manufactured by Nippon Parkerizing Co., Ltd., zinc phosphate treatment) at 170 ° C.-30 Heat cured for minutes. After that, "Lugabake AM" (trade name, manufactured by Kansai Paint Co., Ltd., polyester resin / melamine resin-based intermediate coating for automobiles)
Is applied so that the dry film thickness becomes 30 μm.
Bake for 30 minutes.

Thereafter, the water-based paint NO. 1 to water-based paint NO. 4 was painted. Next, at 80 ° C
Preheat in 10 minutes, "Magiclon HK-4"
(Kansai Paint Co., Ltd., trade name, acrylic melamine clear topcoat paint) was applied. The coating film thickness is based on the water-based paint NO. 1 to water-based paint NO. 4 was 8 to 20 μm, and Magiclon HK-4 was 30 to 50 μm. Next, after setting at room temperature for 10 minutes, the resultant was baked at 140 ° C. for 30 minutes using a hot air electric dryer, and the obtained test plate was subjected to the following performance tests. Table 2 shows the performance results of the test plate.

[0050]

[Table 2] Test method (Note 1) Accelerated weathering resistance: QUV accelerated baculo test using an accelerating tester manufactured by Q Panel Co. (UV irradiation 16 hours / 60 ° C,
The coating film after 1000 hours of ice flocculation at 8 hours / 50 ° C.) was observed, and the presence or absence of abnormalities such as blistering, discoloration, peeling, and the like was evaluated by comparison with those before the test.

Evaluation: Evaluation of appearance coating film A: No blistering, discoloration, peeling, etc. are recognized.

Δ: Swelling, discoloration, peeling, etc. are partially observed. X: Swelling, discoloration, peeling, etc. are remarkably observed. (Note 2) Adhesion: The plate after the above-mentioned test was compared with the clear coating film in Examples and Comparative Examples. Using a cutter knife, scratches were made at intervals of 2 mm to reach the base material of 10 pieces each in the vertical and horizontal directions so as to reach the aqueous coating film of the example. After forming 100 squares on the coating film, cellophane was applied to the surface. The tape was peeled off sharply perpendicular to the coating.

Evaluation: Number of remaining coating films / 100 ○: 100/100 △: 90/100 to 99/100 ×: Less than 90/100 (Note 3) Water resistance: Each test plate Was immersed in a constant temperature bath at 40 ° C. for 7 days, dried at room temperature for 2 hours, and then, using a cutter knife, scratches reaching 10 bases each vertically and horizontally perpendicular to each other were cut on the coating at 100 mm intervals at 2 mm intervals. After forming the eyes, a cellophane tape was peeled off the surface perpendicularly and sharply to the coating.

Evaluation: Number of remaining coating films / 100 ○: 100/100 Δ: 90 to 99/100 ×: Less than 90/100

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J038 CC021 CC071 CC081 CG141 CH031 CH041 CH071 CH081 CJ131 CL001 DA112 DG302 GA01 GA02 GA03 GA06 GA12 GA13 JB18 KA03 KA12 MA08 MA10 NA03 PB07 PC02

Claims (4)

[Claims] An aqueous emulsion (A) and a general formula
Bisbenzotriazole phenol represented by (1)
An aqueous coating composition comprising the compound (C). Embedded image General formula (1)(Where A is an alkylene group, -O-, -NH-, -S
-, -SO-, or -SO _Two-Indicates that n is 0 or 1
is there. R₁And R_TwoAre the same or different, and
Linear or branched hydroxyal having a prime number of 1 to 12
Kill group, radical polymerizable unsaturated group, (meth) acryloy
Represents a hydroxyl group. Also R_ThreeAnd R_Four Are the same or different, water
Elemental atom, alkyl group having 1 to 4 carbon atoms, 1 to 4 carbon atoms
Represents an alkoxy group, an aryl group or a halogen atom.
You. ) 2. The aqueous coating composition according to claim 1, further comprising a crosslinking agent (B). 3. The aqueous coating composition according to claim 2, wherein the crosslinking agent (B) is one of a blocked isocyanate compound and an amino resin. 4. The aqueous coating composition according to claim 2, wherein a bisbenzotriazole phenol compound (C) is added to the crosslinking agent (B), and the resulting mixture is added to the aqueous emulsion (A).