JP2002003538A - Copolymer emulsion, and aqueous coating composition containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a two liquid type aqueous coating composition which is excellent in weather resistance and stability. SOLUTION: This copolymer emulsion is obtained by emulsion polymerizing the mixture which consists of 0.1-10 wt.% bisbenzotriazolephenol compound (a), 5-60 wt.% radical polymerizable unsaturated monomer having a cycloalkyl group (b), 5-30 wt.% radical polymerizable unsaturated monomer having a hydroxy group (c) and 0-89.9 wt.% another radical polymerizable unsaturated monomer, and the cold drying aqueous coating composition capable of being cured and dried is obtained by blending an aqueous base resin (I) comprising the copolymer emulsion as a main component with a polyisocyanate compound as a curing agent (II).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a two-part aqueous coating composition capable of forming a coating film having extremely excellent weather resistance, durability, and gloss. The coating composition of the present invention is very useful especially for building exterior use.

[0002]

2. Description of the Related Art An aqueous coating composition using a polyisocyanate compound as a curing agent as a base emulsion based on a copolymer emulsion to be applied to a building or a building, has a problem in that an object to be coated is exposed to ultraviolet light. It is often exposed to a strong environment, and the components in the coating film are deteriorated, and the coating film is broken, discolored, and faded. Also, from the viewpoint of maintenance-free and the like, durability of a coating film has been regarded as important.

In order to prevent this, an ultraviolet absorber is added particularly to the water-based paint, and examples thereof include cyanoacrylate, piperidinyl, benzophenone, and benzotriazole. However, the weather resistance of the coating film due to these ultraviolet absorbers is insufficient. In particular, in order to improve the weather resistance under severe conditions as in the above-mentioned two-pack water-based paint, a large amount of the ultraviolet absorber is added to the paint. Must.

[0004] However, in a two-pack water-based 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 affects the color of the coating film. Alternatively, 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 aqueous paint component contains a copolymer emulsion obtained by emulsion polymerization of a bisbenzotriazole phenol compound with a radical polymerizable unsaturated monomer mixture having a specific composition. As a result, it was found that a coating film having extremely excellent weather resistance could be formed, and the present invention was completed. That is, the present invention provides: 0.1 to 10% by weight of a bisbenzotriazole phenolic compound (a) represented by the general formula (1), and 5 to 60% by weight of a radically polymerizable unsaturated monomer (b) having a cycloalkyl group A mixture containing 5 to 30% by weight of a hydroxyl group-containing radically polymerizable unsaturated monomer (c) and 0 to 89.9% by weight of another radically polymerizable unsaturated monomer (d) is emulsion-polymerized. A copolymer emulsion characterized by being obtained by

[0007]

Embedded image

(Wherein A is an alkylene group, —O—, —N
H-, -S-, -SO-, or -SO _Two-Indicates that n is
It is 0 or 1. R₁And R_TwoAre the same or different,
Group or a linear or branched hydride having 1 to 12 carbon atoms
Loxyalkyl group or radically polymerizable unsaturated group,
T) represents an acryloyl group. Also R_ThreeAnd R_Four Is the same or
Is different from a hydrogen atom, an alkyl group having 1 to 4 carbon atoms,
C 1-4 alkoxy, aryl or halogen
Indicates the atom. 2.) Water comprising the copolymer emulsion according to 2.1 as a main component
Polyisocyanate as a curing agent (II)
An ever-dry water-based paint composition containing an anate compound
Thing, 3. 1 mole of hydroxyl group contained in the aqueous base material (I)
On the other hand, the isocyanate group contained in the curing agent (II) is
Described in item 2, which is 0.2 to 3.0 moles.LoadingAqueous paint composition
About things.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The copolymer emulsion of the present invention comprises a bisbenzotriazolephenol compound (a) represented by the general formula (1) (hereinafter, may be abbreviated as compound (a)), a polymerizable unsaturated compound having a cycloalkyl group. It is obtained by emulsion-polymerizing a mixture comprising the monomer (b), the hydroxyl-containing polymerizable unsaturated monomer (c) and the other polymerizable unsaturated monomer (d) in the presence of an emulsifier and a polymerization catalyst. It is a copolymer emulsion in which the compound (a) is included in emulsion particles.

The compound (a) serves as an ultraviolet absorber, and is added simultaneously with the emulsion polymerization of the monomer mixture described later and incorporated into the emulsion particles. In particular, the compound (a) has a (meth) acryloyl group in the molecule. In the case where the polymer has a hydroxyl group or a hydroxyalkyl group, it is copolymerized with another monomer and incorporated into the emulsion particles. And improve the weather resistance of the coating film without being eluted from the coating film even in a long-term blackout.

The alkylene group used in the portion [A] of the general formula (1) includes methylene, ethylene, propylene, isopropylene, 2-butylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, 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 (a) includes, for example, methyl, ethyl,
Propyl, isopropyl, butyl, isobutyl, sec
-Butyl, tert-butyl, pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, etc.
And a group in which 1 to 3 hydroxyl groups are substituted at arbitrary positions of 1 to 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 radical polymerizable unsaturated group corresponding to R ₁ and R ₂ in the compound (a) has, for example, a (meth) acryloyl group, a styryl group, a vinyl ester group, a vinyl ether group, and the like at the terminal of the alkylene oxide chain. In particular, since the (meth) acryloyl group has a crosslinking property, the (meth) acryloyl group is easily incorporated into the copolymer emulsion.

The alkyl group having 1 to 4 carbon atoms corresponding to R ₃ and R ₄ in the compound (a) includes, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s
Examples thereof include linear or branched ones such as ec-butyl and tert-butyl. The alkoxy group having 1 to 4 carbon atoms corresponding to R ₃ and R ₄ in the compound (a) includes, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, te
Linear or branched ones such as rt-butoxy are exemplified.

The aryl group corresponding to R ₃ and R ₄ in the compound (a) is, for example, a group 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 (a) 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)
Phenyl disulfone and the like.

Those having a (meth) acryloyl group include 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4- (meth) acryloyloxy-2-hydroxybenzene], 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-benzotriazole-
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-2H-benzotriazol-2-yl) -4- (3- (meth) acryloyloxypropyl) phenol], 2,2'-methylenebis [6- ( 5-bromo-2H-benzotriazole-2-
Yl) -4- (3- (meth) acryloyloxypropyl) phenol], 2,2'-methylenebis [6- (2
H-benzotriazol-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-2)
H-benzotriazol-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 (a) can be used alone or in combination of two or more.
Further, together with the compound (a), if necessary, another conventionally known ultraviolet absorber and / or light stabilizer may be added. Other ultraviolet absorbers include, for example, phenyl salicylate
Salicylic acid derivatives such as p-octylphenyl salicylate and 4-t-butylphenyl salicylate;
4-dihydroxybenzophenone, 2-hydroxy-4
-Methoxybenzophenone, 2,2'-dihydroxy-
4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-octadecyloxybenzophenone, sodium 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfobenzophenone,
2,2 ', 4,4'-tetrahydroxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 5-chloro-2-hydroxybenzophenone, resorcinol monobenzoate, 2,4-dibenzoyl resorcinol, , 6-dibenzoylresorcinol,
Benzophenones such as hydroxydodecylbenzophenone, 2,2'-dihydroxy-4 (3-methacryloxy-2-hydroxypropoxy) benzophenone; 2
Benzotriazole-based compounds such as-(2'-hydroxy-5'-methylphenyl) benzotriazole and other compounds (such as anilide oxalate and cyanoacrylate); and the light stabilizers include hindered amines. Derivatives, specifically, bis- (2,2 ', 6,6'-
Tetramethyl-4-piperidinyl) sebate, 4-benzoyloxy-2,2 ', 6,6'-tetramethylpiperidine, and the like, and one or more of these can be appropriately selected and used.

Next, as the radically polymerizable unsaturated monomer (b) having a cycloalkyl group, for example, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, Cyclododecyl (meth) acrylate and the like can be mentioned, and one or more of them can be appropriately selected and used.

The hydroxyl group-containing radically polymerizable unsaturated monomer (c) includes, for example, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, Allyl alcohol and the like can be mentioned.

Other radically polymerizable unsaturated monomers (d) which can be radically polymerized with the above-mentioned monomers and the like include, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, acrylic T-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, alkyl acrylates such as lauryl acrylate, 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, and itaconic acid Esters, maleic esters such as dimethyl maleate,
Fumaric acid esters such as dimethyl fumarate, styrene, α
-Methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-tert-butylstyrene, benzyl acrylate, benzyl methacrylate,
Acrylonitrile, methacrylonitrile, vinyl acetate, etc., isobornyl acrylate, isobornyl methacrylate, ethylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, divinylbenzene, allyl (meth) Examples thereof include those having a plurality of reactive double bonds such as acrylate, and silane compounds such as trialkoxyvinylsilane and γ-methacryloyloxyalkyl trialkoxysilane.

Further, there may be mentioned a radical polymerizable unsaturated monomer having an acidic group such as a carboxyl group or a sulfonic acid group. Examples of the monomer having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid and ethacrylic acid. Examples of monomers having a sulfonic acid group, such as sulfonic acid, propylacrylic acid, isopropylacrylic acid, and itaconic acid, include ethylsulfo (meth) acrylate. In addition, it is preferable that some of the acidic groups of the radical polymerizable unsaturated monomer having an acidic group are sulfonic acid groups. It is thought that the sulfonic acid group is effective in accelerating the curing. The compound (a), the radical polymerizable unsaturated monomer (b) having a cycloalkyl group, the hydroxyl group-containing radical polymerizable unsaturated monomer (c) and the other radical polymerizable unsaturated monomer (d )) In the mixture is 0.1 to 10% by weight, preferably 0.5% by weight of the compound (a) based on the total solid content.
-5% by weight, and 5-60% by weight, preferably 5-3% by weight, of a radical polymerizable unsaturated monomer (b) having a cycloalkyl group.
0% by weight, hydroxyl-containing radically polymerizable unsaturated monomer (c)
5 to 30% by weight, preferably 5 to 20% by weight, and the other polymerizable unsaturated monomer (d) is in the range of 0 to 89.9% by weight, preferably 45 to 89.5% by weight. .

When the amount of the compound (a) is less than 0.1% by weight, the weather resistance is not improved to improve the weather resistance. When the amount exceeds 10% by weight, the stability of the water-based paint is reduced, and the radical polymerizable unsaturated monomer having a cycloalkyl group is used. When the amount of the monomer (b) is less than 5% by weight, a coating film having a sufficiently high weather resistance cannot be obtained. On the other hand, when the amount exceeds 60% by weight, the coating film tends to crack over time.

Further, when the hydroxyl group-containing radically polymerizable unsaturated monomer (c) is less than 5% by weight, the properties of the coating film become insufficient. On the other hand, when it exceeds 30% by weight, the initial water resistance of the obtained coating film is deteriorated. It is not preferable because the coating workability may be reduced due to the decrease and the viscosity of the paint being increased.

The copolymer emulsion is a copolymer emulsion obtained by blending these radically polymerizable monomers with an emulsifier and a catalyst and performing an emulsion polymerization reaction. This 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 emulsifier used in the production of the copolymer emulsion 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 mixing amount of the emulsifier is 0.5 to 10 with respect to 100% by weight of the solid content of the copolymer emulsion.
The range of the weight% is preferably 1.0 to 5.0% by weight.
When the amount is less than 0.5% by weight, the water dispersibility of the copolymer emulsion is reduced, and the stability is deteriorated. On the other hand, if it exceeds 10% by weight, the water resistance of the formed coating film is undesirably reduced. Examples of the polymerization catalyst include peroxo-2-ammonium sulfate. The copolymer emulsion of the present invention obtained as described above has a weight average molecular weight of 1,000 to 200,0
The glass transition temperature is desirably in the range of −10 to 80 ° C., and the particle size of the emulsion is 50 to 300.
It is desirably within the range of nm.

The water-based coating composition of the present invention is a two-pack water-based coating comprising the water-based base (I) and the curing agent (II) containing the above-mentioned copolymer emulsion as a main component. The aqueous base base material (I) may further include, if necessary, other water-dispersible resins and water-soluble resins, pigments such as color pigments and extenders, pigment dispersants, film-forming auxiliaries, curing catalysts, defoamers. Additives for paints, such as agents, thickeners and antifreezing agents, can also be added.

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 curing agent (II) is preferably a polyisocyanate compound having at least two isocyanate groups in one molecule, and can be added to the aqueous base material (I) and stirred and mixed. From the viewpoint of properties, the polyisocyanate compound can be used after being modified with a polyoxyethylene-based surfactant or the like, a silane coupling agent, or the like.

The above polyisocyanate compound is preferably a polyisocyanate compound other than an aliphatic and / or alicyclic compound. In the case of an aromatic polyisocyanate compound, the weather resistance of a coating film is deteriorated, which is not preferable.

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

The aqueous coating composition of the present invention is a two-pack type aqueous coating composition obtained by adding the above-mentioned aqueous base base (I) and the curing agent (II) immediately before use and stirring and dispersing. The amount of the isocyanate group contained in the curing agent (II) is 0.2 to 3.0 mol, preferably 0.5 to 2.5 mol, per 1 mol of the hydroxyl group contained in the aqueous base material (I). And mix for use.

The application of the aqueous coating composition of the present invention is carried out by a conventionally known method such as spray coating, roller coating, brush coating, immersion and the like. The amount of coating is not particularly limited, but generally about 50 to 400 g / m ² is appropriate.

[0038]

According to the present invention, a copolymer emulsion obtained by emulsion polymerization of a bisbenzotriazolephenol compound (a) with a monomer containing a specific radically polymerizable unsaturated monomer is used as a main component. Aqueous base agent (I),
An aqueous coating composition having the composition of the curing agent (II) can form a coating film having excellent weather resistance, and is very useful especially for building exterior use. Also, the reason why high weather resistance can be obtained is that
Since the compound (a) is included in the particles of the copolymer emulsion, the effect is exhibited without being eluted by rainwater or the like even after the formation of the coating film.

[0039]

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 1 of Copolymer Emulsion 309 parts of deionized water was placed in a two-liter four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen inlet tube, and New
After adding 0.8 part of col707SF (manufactured by Nippon Emulsifier Co., anionic surfactant, nonvolatile content: 30%), the mixture was replaced with nitrogen and kept at 82 ° C. with stirring. 21 parts of a pre-emulsion obtained by emulsifying the following components and 0.25 part of ammonium persulfate were added thereto, and after 20 minutes, the remaining emulsion was added dropwise over 4 hours. Deionized water 85 parts Newcol 707SF 0.5 parts Styrene 20 parts Cyclohexyl methacrylate 15 parts Methyl methacrylate 22 parts n-butyl methacrylate 17 parts 2-ethylhexyl acrylate 15 parts 2-hydroxyethyl methacrylate 10 parts Acrylic acid 1 part Octyl mercaptan 1 (Note 1) 2 parts of RUVA-100 0.25 parts of ammonium persulfate After maintaining at 82 ° C for 2 hours from the end of dropping, the temperature in the flask was lowered to 40 ° C. PH 8.5 with ammonia water
And a copolymer emulsion (A) having a solid content of 50% by weight.
-1) was obtained. (Note 1) "RUVA-100" (trade name, manufactured by Otsuka Chemical Co., Ltd., 2,2'-methylenebis [6- (2H-benzotriazole-
2-yl) -4- (2-hydroxyethyl) phenol])

[0041]

[Image Omitted] RUVA-100

Example 2 and Comparative Examples 1 to 4 The procedure of Example 1 was repeated except that the amount of the monomer and the amount of the catalyst in the pre-emulsion were as shown in Table 1. Combined emulsion (A-2)
To (A-6).

[0043]

[Table 1]

Preparation of Curing Agent (II) In a four-necked flask equipped with a stirrer, thermometer, reflux tube and nitrogen inlet tube, 225 parts of methoxypolyethylene ether glycol having a number average molecular weight of 550 and 1,6-hexamethylene diisocyanate 871 were added. The reaction mixture was reacted at 70 ° C. for 6 hours after replacement with nitrogen. The obtained reaction solution was applied to a thin film distillation apparatus to remove unreacted 1,6-hexamethylene diisocyanate, thereby obtaining a monoisocyanate compound having methoxypolyethylene ether glycol.

Next, 37 parts of diethanolamine was placed in a separate flask, and 250 parts of the monoisocyanate compound having methoxypolyethylene ether glycol obtained in Preparation Example 1 was cooled to 70 ° C. while air-cooling after purging with nitrogen.
The solution was gradually dropped so as not to exceed. After the completion of the dropwise addition, the mixture was stirred at -70 ° C for about 1 hour, and it was confirmed that the isocyanate group had disappeared. Thus, an emulsifier was obtained.

In a separate flask, 42 parts of this emulsifier and 358 parts of “Takenate D170HN” (trimer of 1,6-hexamethylene diisocyanate, manufactured by Takeda Pharmaceutical Co., Ltd.) were added, and N-β- (aminoethyl)-was further added. A hexamethylene polyisocyanate compound as a water-dispersible curing agent (II) was obtained by adding 12 parts of γ-aminopropyltrimethoxysilane and stirring at 70 ° C. for 6 hours. Isocyanate content 17.7% by weight, viscosity 800 cps
Met.

Preparation of Pigment Paste A raw material having the following composition is placed in a 4 liter stainless steel container,
The mixture was stirred with a disper for 30 minutes to obtain a pigment paste. Water 960 parts Nopco Santo K (manufactured by San Nopco, trade name, pigment dispersant) 48 parts Adekanol VH420 (manufactured by Asahi Denka Co., trade name, thickener) 16 parts SN deformer A63 (manufactured by San Nopco, trade name, defoaming) 32 parts Titanium white 3520 parts Ethanol 288 parts Preparation of aqueous coating compositions Examples 3 and 4 and Comparative Examples 5 to 8 Next, 280 parts of pigment dispersion paste were placed in a 1-liter stainless steel container, Each of 500 parts of the polymer emulsions (A-1) to (A-6) contains "SX-
997 "(Note 2) 50 parts," Texanol solvent "(Note 3) 20 parts," SN Deformer A63 "3.6 parts,
0.5 part of "Adecanol VH420" and 62.5 parts of tap water were blended and stirred with a disper to obtain an aqueous base agent (I). To this, 80 parts of a curing agent (II) was added, and the mixture was thoroughly stirred. 1 to NO. 6 was obtained. Table 2 shows the composition breakdown.

[0048]

[Table 2]

(Note 2) SX-997: manufactured by Nippon Synthetic Rubber Co., Ltd., trade name, acrylic resin emulsion, solid content 35% (Note 3) Texanol solvent: 2,2,4-trimethyl-1,3-
Preparation of pentanediol monoisobutyrate coated test plate A slate plate (90 × 300 × 6 mm) was coated with VP sealer white (manufactured by Kansai Paint Co., trade name, solvent type sealer) so that the coating amount became 100 g / m ^2. What was coated and dried with a roller was used as a plate to be coated, on which the aqueous coating composition No. 1 obtained in Examples and Comparative Examples was applied. 1 to NO. 6 to 15
Each test plate was prepared by painting twice with a spray so as to obtain 0 g / m ² and drying at room temperature for 7 days. The obtained test plate was subjected to the following performance tests. Table 3 shows the test results.

[0050]

[Table 3]

(Note 4) Accelerated weather resistance: For each test plate,
The gloss retention (%) after exposure for 2,000 hours with a sunshine weatherometer was examined. (Note 5) 60 ° gloss: The 60 ° gloss (specular reflectance) of the coating film surface of each test plate was measured. (Note 6) Adhesion: The plate after the accelerated weathering test was cut vertically and horizontally by using a cutter knife to reach the material.
After making 0 scratches at intervals of 2 mm to form 100 gobangs on the coating film, a cellophane tape was peeled off the surface perpendicularly and rapidly to the coating film.

Evaluation: Number of remaining coating films / 100 ○: 100/100 △: 90-99 / 100 ×: Less than 90/100

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 220/00 C08F 220/00 220/28 220/28 222/00 222/00 C09D 5/02 C09D 5 / 02 157/00 157/00 175/04 175/04 F-term (reference) 4J011 AA05 BA03 BB01 DA01 KA04 KA12 KA16 KA24 KB22 PA03 PA04 PA07 PA13 PA43 PB24 PB25 PC02 PC06 4J038 DG191 DG271 DG281 DG291 GA01 GA10 GA05 GA06 GA08 GA08 HA156 JB35 JC02 KA07 LA02 MA08 MA10 NA01 NA03 PA18 PB05 4J100 AB02R AB03R AB16R AD03Q AG04R AJ01P AJ02R AJ08P AL03R AL04R AL05R AL08P AL08R AL08S AL09Q AL34R AL44R AL62R AL63R BA02 BA01 BA03 BA03 BA02 BA03 BA02 CA05 CA06 CA31 DA01 DA25 DA36 EA06 EA09 FA20 HA53 HC51 HD07 JA01

Claims (3)

[Claims] 1. Bisbeth represented by the general formula (1)
Nzotriazole phenolic compound (a) is 0.1 to
10% by weight, radical polymerizable having a cycloalkyl group
5 to 60% by weight of unsaturated monomer (b),
5-30% by weight of the cal polymerizable unsaturated monomer (c), and
Other radically polymerizable unsaturated monomer (d) is 0 to 8
9.9% by weight of a mixture obtained by emulsion polymerization
A copolymer emulsion characterized by the following: Embedded image(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) acryl
Represents a Royl group. Also R_ThreeAnd R_Four Are the same or different
A hydrogen atom, an alkyl group having 1 to 4 carbon atoms, 1 carbon atom
To 4 alkoxy groups, aryl groups or halogen atoms
Show. ) 2. An air-drying aqueous coating composition obtained by mixing a polyisocyanate compound as a curing agent (II) with an aqueous base main ingredient (I) mainly comprising the copolymer emulsion according to claim 1. 3. The aqueous coating composition according to claim 2, wherein the isocyanate group contained in the curing agent (II) is 0.2 to 3.0 mol per 1 mol of the hydroxyl group contained in the aqueous base material (I). Composition.