JP5635845B2 - Water-based paint composition - Google Patents

Description

  The present invention relates to a water-based coating composition that can be applied mainly to interior and exterior coating of buildings.

  In recent years, environmental pollution and effects on the human body have been taken into account, and the number of cases in which water-based paints are used instead of solvent-based paints has increased considerably.

  For example, water-based paints in the field of architectural paints are well known as room temperature drying-type water-based paint compositions that form a coating film using fusion of resin emulsion particles. In this field, a viscosity modifier (thickener, sedimentation) is added to the aqueous coating composition for the purpose of preventing the precipitation of the pigment at the storage stage of the aqueous coating composition or imparting a sense of unevenness to the formed coating film. In some cases, it may be referred to as an inhibitor).

  As viscosity modifiers blended in an aqueous coating composition using such a resin emulsion, there are associative viscosity modifiers and cellulose-based viscosity modifiers.

  The associative viscosity modifier generally has a hydrophilic part and a hydrophobic part in one molecule, and in an aqueous medium, the hydrophobic part is adsorbed on the surface of the pigment or emulsion particles in the paint, It is a viscosity modifier that effectively forms a thickening action by forming a network structure when the sexing parts associate with each other.

  The associative viscosity modifier usually forms a network structure by hydrophobic interaction and develops viscosity. On the other hand, since the hydrophobic interaction has a relatively weak binding force, when a large shear force is applied, the network structure is broken and the viscosity is lowered. For this reason, the water-based paint containing the associative viscosity modifier has a viscosity characteristic that the viscosity decreases as the shear rate increases.

  Patent Document 1 discloses an aqueous coating composition containing a copolymer aqueous dispersion having a specific particle size distribution and an anti-settling agent. So-called associative viscosity modifiers such as polyether compounds are used as anti-settling agents. It is described as suitable. According to such a water-based paint composition, in addition to good storage stability and coating workability, it is excellent in the formation of uneven patterns on the coated surface when coated with a roller having a coarse mesh roller cover, etc. It has the performance required for water-based paints.

  On the other hand, cellulosic viscosity modifiers include those that are water-soluble, such as methylcellulose, hydroxyethylcellulose, etc., that are associated with each other by hydrogen bonding with water molecules to form a network structure and develop viscosity. There is a type that develops viscosity by ionic repulsion between carboxylic acids, such as methylcellulose. A water-based paint containing a cellulosic viscosity modifier has a viscosity characteristic in which the viscosity decreases as the shear rate increases.

  Patent Document 2 discloses a water-repellent film-forming composition containing an emulsion containing a specific component as an active ingredient and an organic solvent. As a thickener for improving the coating workability of the composition, a fibrous derivative system, etc. The so-called cellulosic viscosity modifier is described as being suitable.

  In this way, in the field of architectural water-based paints, we have selected a viscosity modifier that shows the optimal viscosity behavior according to the nature, purpose of use, and application of the water-based paint, and that matches the performance of the paint and the formed coating film. However, there are cases where the paint viscosity is extremely lowered at the time of paint toning, pigment aggregation or the like occurs, and the toning stability is lowered or a desired texture cannot be obtained.

JP 2006-306994 A JP 2005-15727 A

  An object of the present invention is to provide a water-based coating composition that is excellent in coating workability because a viscosity-reducing phenomenon at the time of paint toning is suppressed.

  As a result of intensive studies to achieve the above object, the present inventors have found that a copolymer which is a graft polymer having a specific main chain and a side chain and having a specific weight average molecular weight, and a specific weight It has been found that by using a copolymer having a polyoxyalkylene chain having an average molecular weight and an acid value in combination, an aqueous coating composition having good coating workability can be obtained even after toning.

That is, the present invention
1. An aqueous coating composition comprising a copolymer (A), a copolymer (B) and a resin emulsion component (C) (excluding the copolymer (A)), wherein the copolymer (A) is (m -1) A polymerizable unsaturated monomer (a) having 3 to 24 carbon atoms, which is a monoesterified product of (meth) acrylic acid and a monohydric alcohol having 3 to 24 carbon atoms , is used in an amount of 5 to 100. A macromonomer having a number average molecular weight of 1,000 to 7,000 having a polymer chain and a polymerizable unsaturated group obtained by polymerizing the monomer component (I) contained by mass (m−2), ) N- substituted (meth) acrylamide, a polymerizable unsaturated monomer having at least one nonionic hydrophilic group selected from the group consisting of polymerizable unsaturated monomer and N- vinyl-2-pyrrolidone having a polyoxyalkylene chain And (m-3) a copolymer having a weight average molecular weight of 100,000 or more obtained by copolymerizing the monomer component (m) comprising other polymerizable unsaturated monomer, and the copolymer (B) is The acid value obtained by copolymerizing a polymerizable unsaturated monomer component containing 10 to 40% by mass of a polymerizable unsaturated monomer having a polyoxyalkylene chain is in the range of 20 to 100 mg KOH / g, and the weight average molecular weight is 100, An aqueous coating composition characterized by being a copolymer of less than 000,
2. The aqueous coating composition according to 1, wherein the polymerizable unsaturated monomer (m-2) having a nonionic hydrophilic group is N-substituted (meth) acrylamide,
3. The copolymerization ratio of (m-1), (m-2) and (m-3) in the copolymer (A) is such that (m-1) is 1 to 29% by mass and (m-2) is 20 to 20%. 99% by mass, the water-based coating composition according to item 1 or 2, wherein (m-3) is in the range of more than 0 to 79% by mass,
4). Item 4. The monomer component (I) contains at least a part of the hydroxyl group-containing polymerizable unsaturated monomer in an amount of 5 to 60% by mass based on the total mass of the monomer component (I). Water-based paint composition,
5. The water-based paint composition according to any one of claims 1 to 4, wherein the resin emulsion component (C) comprises an acrylic resin emulsion, and the acrylic resin emulsion is provided with water dispersibility by a surfactant. ,
6). The content of the copolymer (A) and the copolymer (B) is 0.01 to 10 parts by mass (B) based on 100 parts by mass of the resin solid content of the resin emulsion component (C). The water-based coating composition according to any one of 1 to 5, wherein is in the range of 0.01 to 10 parts by mass,
7). A coating film forming method for forming a coating film on the object using the aqueous coating composition according to any one of items 1 to 6,
8). A coated article coated by the method of forming a coating film according to item 7,
About.

  According to the water-based coating composition of the present invention, by combining a specific copolymer and a specific copolymer, it is hard to sag than when a conventional viscosity modifier is used, and the coating workability is good, and the finished appearance It is possible to form an excellent coating film even under conditions of room temperature drying. In addition, the water-based coating composition according to the present invention has a good toning stability because the viscosity reduction phenomenon is suppressed, and can form a coating film having an excellent finished appearance.

  Hereinafter, each component contained in the aqueous coating composition of the present invention will be described in detail.

Copolymer (A)
The copolymer (A) in the present invention polymerizes the monomer component (I) containing 5 to 100% by mass of the polymerizable unsaturated monomer (a) having (m-1) an alkyl group having 3 to 24 carbon atoms. A macromonomer having a polymer chain and a polymerizable unsaturated group and a number average molecular weight in the range of 1,000 to 7,000, and (m-2) a polymerizable unsaturated group having a nonionic hydrophilic group It is a copolymer having a weight average molecular weight of 100,000 or more obtained by copolymerizing a monomer component (m) composed of a monomer and (m-3) other polymerizable unsaturated monomer.

  The copolymer (A) has a viscosity characteristic in which the viscosity is high and the viscosity decreases as the shear rate increases. In particular, even when added to an emulsion-based coating composition containing a large amount of a resin emulsion, the viscosity developability is stable and has a viscosity characteristic in which the viscosity decreases as the shear rate increases. Since it has such excellent viscosity characteristics, the copolymer (A) can be suitably used as a viscosity modifier.

Polymerizable unsaturated monomer having an alkyl group having 3 to 24 carbon atoms (a)
As the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms, for example, a monoesterified product of (meth) acrylic acid and a monohydric alcohol having an alkyl group having 3 to 24 carbon atoms is used. be able to. Specifically, for example, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl, for example (Meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate (lauryl (meth) acrylate), tridecyl (meth) acrylate, Stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl ( ) Acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, alkyl such as tricyclodecanyl (meth) acrylate, or cycloalkyl (meth) acrylate, and these may be used alone or in combination of two or more. Can be used.

  In the present specification, “(meth) acrylate” means acrylate or methacrylate, and “(meth) acrylic acid” means acrylic acid or methacrylic acid. In addition, “(meth) acryloyl” means acryloyl or methacryloyl, and “(meth) acrylamide” means “acrylamide or methacrylamide”.

  As the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms, a polymerizable unsaturated monomer having an alkyl group having 4 to 18 carbon atoms is preferable from the viewpoint of paint thinning suppression effect. A polymerizable unsaturated monomer having an alkyl group of 4 to 8 is more preferable. Of these, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, and 2-ethylhexyl methacrylate are preferable, and n-butyl methacrylate and 2-ethylhexyl methacrylate are suitable.

Monomer component (I)
The monomer component (I) contains 5 to 100% by mass of the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms. Among these, from the viewpoint of the finish of the resulting coating film, the content of the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms in the monomer component (I) is 30 to 95% by mass. , Preferably it is in the range of 45 to 90% by mass.

  The monomer component (I) can contain a polymerizable unsaturated monomer (b) other than the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms. In this case, the monomer component (I) is other than the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms and the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms. The polymerizable unsaturated monomer (b).

  Examples of the polymerizable unsaturated monomer (b) other than the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms include 1 carbon atom such as methyl (meth) acrylate and ethyl (meth) acrylate. Alkyl (meth) acrylate having an alkyl group of ˜2; aromatic ring-containing polymerizable unsaturated monomer such as benzyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris Polymerizable unsaturated monomers having an alkoxysilyl group such as (2-methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane; perfluorobutylethyl (meta ) Acrylate, perfluorooct Perfluoroalkyl (meth) acrylate such as ruethyl (meth) acrylate; polymerizable unsaturated monomer having a fluorinated alkyl group such as fluoroolefin; polymerizable unsaturated monomer having a photopolymerizable functional group such as maleimide group; N- Vinyl compounds such as vinyl pyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxy Monoesterified product of (meth) acrylic acid such as butyl (meth) acrylate and a dihydric alcohol having 2 to 8 carbon atoms, monoesterified product of the (meth) acrylic acid and a dihydric alcohol having 2 to 8 carbon atoms ε-caprolactone modified form, N-hydroxy Hydroxyl group-containing polymerizable unsaturated monomers such as methyl (meth) acrylamide, allyl alcohol, (meth) acrylate having a polyoxyethylene chain having a hydroxyl group at the molecular end; (meth) acrylic acid, maleic acid, crotonic acid, β- Carboxyl group-containing polymerizable unsaturated monomers such as carboxyethyl acrylate; allyl (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3- Butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate Rate, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1-trishydroxymethylethanedi (meth) acrylate, 1,1,1-trishydroxymethyl Polymerization having at least two polymerizable unsaturated groups in one molecule such as ethanetri (meth) acrylate, 1,1,1-trishydroxymethylpropanetri (meth) acrylate, triallyl isocyanurate, diallyl terephthalate, divinylbenzene Unsaturated monomers; (meth) acrylonitrile, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate Nitrogen-containing polymerizable unsaturated monomers such as adducts of rilamide, glycidyl (meth) acrylate and amines; glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate , 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate, epoxy group-containing polymerizable unsaturated monomers such as allyl glycidyl ether; 2-isocyanatoethyl (meth) acrylate, m —Isocyanato group-containing polymerizable unsaturated monomers such as isopropenyl-α, α-dimethylbenzyl isocyanate; (meth) acrylates having polyoxyethylene chains whose molecular ends are alkoxy groups; acrolein, diacetone acrylic Carbonyl group-containing polymerizable monomers such as vinyl acetate, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formyl styrene, vinyl alkyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone). And saturated monomers. These polymerizable unsaturated monomers can be used alone or in combination of two or more.

  The monomer component (I) preferably contains a hydroxyl group-containing polymerizable unsaturated monomer as at least a part thereof from the viewpoint of the effect of suppressing the thinning of the paint. Specifically, the polymerizable unsaturated monomer (b) other than the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms includes a hydroxyl group-containing polymerizable unsaturated monomer as at least a part thereof. It is preferable to contain.

  Examples of the hydroxyl group-containing polymerizable unsaturated monomer include, for example, the hydroxyl group-containing polymerization exemplified in the description of the polymerizable unsaturated monomer (b) other than the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms. Unsaturated unsaturated monomers. These monomers can be used alone or in combination of two or more.

  Among the hydroxyl group-containing polymerizable unsaturated monomers, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate are particularly preferable. Can be used for

  When the monomer component (I) contains a hydroxyl group-containing polymerizable unsaturated monomer, the proportion of the hydroxyl group-containing polymerizable unsaturated monomer used in that case is determined from the viewpoint of the finish of the formed coating film and water resistance. It is suitable that it is in the range of 5 to 60% by mass, preferably 10 to 55% by mass, based on the total mass of component (I).

  In addition, when the monomer component (I) contains a hydroxyl group-containing polymerizable unsaturated monomer, the hydroxyl value of the polymer obtained by polymerizing the monomer component (I) is the finish and water resistance of the formed coating film. From the viewpoint of the above, it is preferable to be within the range of 20 to 260 mgKOH / g, preferably 40 to 220 mgKOH / g.

Macromonomer (m-1)
The macromonomer (m-1) is composed of a polymer chain obtained by polymerizing the monomer component (I) containing the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms and polymerizable unsaturated monomer. And a macromonomer having a number average molecular weight in the range of 1,000 to 7,000. In the present invention, the macromonomer is a high molecular weight monomer having a polymerizable unsaturated group at the end of the polymer.

  The macromonomer (m-1) preferably has a number average molecular weight in the range of 1,000 to 7,000. Especially, it is suitable that a number average molecular weight exists in the range of 1,000-5,000, Preferably it is 1,000-3,000 from a viewpoint of a paint thinning suppression effect. The number average molecular weight of the macromonomer (m-1) can be adjusted by, for example, the amount of chain transfer agent used, the reaction temperature, the reaction time, and the like when the monomer component (I) is polymerized.

  The macromonomer (m-1) can be obtained by a method known per se. Specifically, for example, it can be obtained by the following method (1), method (2), method (3) and the like.

  Method (1): When the monomer component (I) is polymerized, a polymer is obtained by performing polymerization in the presence of a chain transfer agent containing a first chemically reactive group such as a carboxyl group, a hydroxyl group, and an amino group. A first chemically reactive group is introduced at the end of Next, by reacting the obtained polymer with a polymerizable unsaturated monomer having a second chemically reactive group capable of reacting with the first chemically reactive group in the polymer, a macromonomer (m -1) can be obtained.

  Examples of the chain transfer agent containing a first chemically reactive group such as a carboxyl group, a hydroxyl group, and an amino group include mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 2-mercaptoethanol, and 2-aminoethane. Thiols and the like can be suitably used.

  Examples of the polymerizable unsaturated monomer having a second chemically reactive group for reacting with the first chemically reactive group in the copolymer (A) to introduce a polymerizable unsaturated group include: When the first chemically reactive group is a carboxy group, an epoxy group-containing polymerizable unsaturated monomer; when the first chemically reactive group is a hydroxyl group; an isocyanato group-containing polymerizable unsaturated monomer; In the case where the chemically reactive group is an amino group, an epoxy group-containing polymerizable unsaturated monomer can be preferably used.

  As said epoxy-group-containing polymerizable unsaturated monomer, glycidyl acrylate, glycidyl methacrylate, etc. can be used conveniently, for example. In addition, as the isocyanato group-containing polymerizable unsaturated monomer, for example, isocyanatoethyl methacrylate, m-isopropenyl-α, α-dimethylbenzyl isocyanate and the like can be preferably used.

  Method (2): The macromonomer (m-1) can be obtained by catalytic chain transfer polymerization (CCTP method) using a metal complex. The CCTP method is described, for example, in JP-B-6-23209, JP-B-7-35411, JP-B-9-501457, JP-A-9-176256, Macromolecules 1996, 29, 8083-8089, and the like. ing. Specifically, the macromonomer (m-1) can be produced by subjecting the monomer component (I) to catalytic chain transfer polymerization in the presence of a metal complex. The catalytic chain transfer polymerization can be performed by, for example, a solution polymerization method in an organic solvent, an emulsion polymerization method in water, or the like. Moreover, in the case of superposition | polymerization, you may use a radical polymerization initiator as needed in addition to the said metal complex.

Examples of the metal complex include a cobalt complex, an iron complex, a nickel complex, a ruthenium complex, a rhodium complex, a palladium complex, a rhenium complex, and an iridium complex. Among these, the cobalt complex is efficiently used as a catalytic chain transfer agent. Works. The amount of the metal complex to be used is not particularly limited, but is usually 1 × 10 ⁻⁶ to 1 part by mass, preferably 1 × 10 ^{−4 based on} 100 parts by mass of the total mass of the monomer component (I). It is suitable to be in the range of ~ 0.5 parts by mass.

  Examples of the radical polymerization initiator include benzoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, cumene hydroperoxide, tert-butyl peroxide, di-tert-amyl peroxide, and tert-butyl peroxide. Organic peroxides such as oxylaurate, tert-butylperoxyisopropyl carbonate, tert-butylperoxyacetate, diisopropylbenzene hydroperoxide, tert-butylperoxy-2-ethylhexanoate; azobisisobutyronitrile , Azobis (2,4-dimethylvaleronitrile), azobis (2-methylpropiononitrile), azobis (2-methylbutyronitrile), 4,4′-azobis (4-cyanobutane) ), Dimethylazobis (2-methylpropionate), azobis [2-methyl-N- (2-hydroxyethyl) -propionamide], azobis {2-methyl-N- [2- (1-hydroxybutyl) ] -Propionamide} and the like; and persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate. These polymerization initiators can be used alone or in combination of two or more. The blending amount of the radical polymerization initiator is not particularly limited, but is usually 0.1 to 10 parts by weight, preferably 0.1 to 0.1 parts by weight based on 100 parts by weight of the total weight of the monomer component (I). It is preferable to be within the range of 8 parts by mass.

  Method (3): The macromonomer (m-1) can be obtained by an addition cleavage type chain transfer polymerization method using an addition cleavage type chain transfer agent. The addition-cleavage type chain transfer polymerization method is described in, for example, JP-A-7-2954. Specifically, the macromonomer (m-1) can be produced by subjecting the monomer component (I) to addition-cleavage chain transfer polymerization in the presence of the addition-cleavage chain transfer agent. The addition-cleavage chain transfer polymerization can be performed by, for example, a solution polymerization method in an organic solvent, an emulsion polymerization method in water, or the like. Moreover, in the case of superposition | polymerization, in addition to this addition cleavage type | mold chain transfer agent, a radical polymerization initiator can be used together as needed.

  For example, 2,4-diphenyl-4-methyl-1-pentene (sometimes abbreviated as “α-methylstyrene dimer” or “MSD”) is preferably used as the addition-cleavage chain transfer agent. be able to. The compounding amount of the addition-cleavage type chain transfer agent is not particularly limited, but is usually 1 to 20 parts by mass, preferably 2 to 15 parts by mass, based on 100 parts by mass of the total mass of the monomer component (I). Parts, more preferably in the range of 3 to 10 parts by weight.

  As the radical polymerization initiator, for example, the radical polymerization initiator described in the description of the method (2) can be used. These polymerization initiators can be used alone or in combination of two or more. The blending amount of the radical polymerization initiator is not particularly limited, but is usually 1 to 20 parts by mass, preferably 2 to 15 parts by mass based on 100 parts by mass of the total mass of the monomer component (I). More preferably, it is in the range of 3 to 10 parts by mass.

  Among the methods (1) to (3), the method (1) is a step of polymerizing the monomer component (I) to obtain a polymer, and reacting the obtained polymer with a polymerizable unsaturated monomer. Two reaction steps including a step of introducing a polymerizable unsaturated group into the polymer are necessary. In addition, since the method (2) uses a metal complex, catalytic chain transfer polymerization may occur during the production of a copolymer (graft polymer) described later, and the resulting copolymer may be colored. is there.

  For this reason, the macromonomer (m-1) is an addition-cleavage-type chain using the addition-cleavage-type chain transfer agent of the method (3) from the viewpoints of reducing the number of reaction steps and suppressing the coloring in the resulting copolymer. It is preferable to obtain by a transfer polymerization method.

Polymerizable unsaturated monomer having nonionic hydrophilic group (m-2)
In the present invention, examples of the polymerizable unsaturated monomer (m-2) having a nonionic hydrophilic group include N-substituted (meth) acrylamide, a polymerizable unsaturated monomer having a polyoxyalkylene chain, and N-vinyl- 2-pyrrolidone and the like can be mentioned. These can be used singly or in combination of two or more. Among them, N-substituted (meth) acrylamide is preferable from the viewpoint of the effect of suppressing the viscosity reduction of the paint.

  Examples of the N-substituted (meth) acrylamide include N-methyl acrylamide, N-methyl methacrylamide, N-methylol acrylamide butyl ether, N-methylol methacrylamide butyl ether, N-ethyl acrylamide, N-ethyl methacrylamide, N- n-propylacrylamide, Nn-propylmethacrylamide, N-isopropylacrylamide, N-isopropylmethacrylamide, N-cyclopropylacrylamide, N-cyclopropylmethacrylamide, diacetoneacrylamide, diacetonemethacrylamide, N-hydroxymethyl Acrylamide, N-hydroxymethyl methacrylamide, N-hydroxyethyl acrylamide, N-hydroxyethyl methacrylamide, N, N- Methyl acrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacrylamide, N-methyl, N-ethylacrylamide, N-methyl, N-ethylmethacrylamide, N, N-dimethyl Aminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, N-methylol acrylamide methyl ether, N-methylol methacrylamide methyl ether, N-methylol acrylamide ethyl ether, N-methylol methacrylamide ethyl ether, N-methylol acrylamide propyl ether , N-methylol methacrylamide propyl ether, acryloyl morpholine, methacryloyl morpholine and the like. It can be used in combination up.

  Among these, Nn-propyl acrylamide, Nn-propyl methacrylamide, N-isopropyl acrylamide, N-isopropyl methacrylamide, N-hydroxyethyl acrylamide, N-hydroxy are preferred from the viewpoint of the finish of the formed coating film. Preferred are ethyl methacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide Is more preferable.

  The polymerizable unsaturated monomer having a polyoxyalkylene chain is a monomer containing a polyoxyalkylene chain and a polymerizable unsaturated group in one molecule.

  Examples of the polyoxyalkylene chain include a polyoxyethylene chain, a polyoxypropylene chain, a chain composed of a polyoxyethylene block and a polyoxypropylene block, and a polyoxyethylene block and a polyoxypropylene that are randomly bonded. These polyoxyalkylene chains generally have a molecular weight in the range of about 100 to 5,000, preferably about 200 to 4,000, more preferably about 300 to 3,000. Is preferred.

  Representative examples of the polymerizable unsaturated monomer having a polyoxyalkylene chain include, for example, the following general formula (1)

[Wherein R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom, a methyl group or an ethyl group, more preferably a hydrogen atom or a methyl group. R ³ represents an alkylene group having 2 to 4 carbon atoms, preferably 2 or 3 carbon atoms, more preferably 2 carbon atoms, and m is 3 to 150, preferably 5 to 80, more preferably 8 to 50. Represents an integer, and the m oxyalkylene units (O—R ³ ) may be the same as or different from each other]
The polymerizable unsaturated monomer shown by these can be mentioned.

  Specific examples of the polymerizable unsaturated monomer represented by the general formula (1) include, for example, tetraethylene glycol (meth) acrylate, methoxytetraethylene glycol (meth) acrylate, ethoxytetraethylene glycol (meth) acrylate, n- Butoxytriethylene glycol (meth) acrylate, n-butoxytetraethylene glycol (meth) acrylate, tetrapropylene glycol (meth) acrylate, methoxytetrapyroprene glycol (meth) acrylate, ethoxytetrapropylene glycol (meth) acrylate, n-butoxy Tetrapropylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, polyethylene (polypropylene glycol) Pyrene) glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate, ethoxy polypropylene glycol (meth) acrylate, methoxy polyethylene (propylene) glycol (meth) acrylate And ethoxypolyethylene (propylene) glycol (meth) acrylate and the like, and these can be used alone or in combination of two or more. In the present specification, “polyethylene (propylene) glycol” means a copolymer of ethylene glycol and propylene glycol, and includes both a block copolymer and a random copolymer.

  Among these, from the viewpoint of the finish of the formed coating film, polyethylene glycol (meth) acrylate, polyethylene (propylene) glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypolyethylene (propylene) glycol (meth) acrylate Are preferred, and polyethylene glycol (meth) acrylate and methoxypolyethylene glycol (meth) acrylate are more preferred.

  The polymerizable unsaturated monomer having a polyoxyalkylene chain generally has a number average molecular weight in the range of about 300 to 6,000, preferably about 400 to 5,000, more preferably about 450 to 3,500. Is preferred.

Other polymerizable unsaturated monomers (m-3)
The other polymerizable unsaturated monomer (m-3) is a polymerizable unsaturated monomer other than the macromonomers (m-1) and (m-2). The other polymerizable unsaturated monomer (m-3) can be appropriately selected and used depending on the properties desired for the copolymer.

Specific examples of the polymerizable unsaturated monomer (m-2) other than the macromonomer (m-1) are listed below. These can be used alone or in combination of two or more.
(I) Alkyl or cycloalkyl (meth) acrylate: For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) Acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) Acrylate, cyclododecyl (meth) acrylate, tricyclodecanyl (meth) acrylate.
(Ii) Polymerizable unsaturated monomer having an isobornyl group: for example, isobornyl (meth) acrylate.
(Iii) Polymerizable unsaturated monomer having an adamantyl group: for example, adamantyl (meth) acrylate and the like.
(Iv) Polymerizable unsaturated monomer having a tricyclodecenyl group: For example, tricyclodecenyl (meth) acrylate and the like.
(V) Aromatic ring-containing polymerizable unsaturated monomer: For example, benzyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene and the like.
(Vi) Polymerizable unsaturated monomer having a hydrolyzable silyl group: For example, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltri Isopropoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxypropylmethyldi Ethoxysilane, γ- (meth) acryloyloxypropyltri-n-propoxysilane, γ- (meth) acryloyloxypropyltriisopropoxysilane, vinyltriacetoxysilane, β- (meth) acrylo Iroxyethyltrimethoxysilane and the like.
(Vii) Polymerizable unsaturated monomer having a fluorinated alkyl group: For example, perfluoroalkyl (meth) acrylate such as perfluorobutylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate; fluoroolefin and the like.
(Viii) A polymerizable unsaturated monomer having a photopolymerizable functional group such as a maleimide group.
(Ix) Vinyl compound: For example, N-vinyl pyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate and the like.
(X) Phosphoric acid group-containing polymerizable unsaturated monomer: For example, 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl acid phosphate, 2-methacryloyloxypropyl acid phosphate and the like.
(Xi) Hydroxyl-containing polymerizable unsaturated monomer: For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. Monoesterified product of (meth) acrylic acid and C2-8 dihydric alcohol; ε-caprolactone modified product of monoesterified product of (meth) acrylic acid and C2-8 dihydric alcohol; allyl Alcohol etc.
(Xii) Carboxyl group-containing polymerizable unsaturated monomer: For example, (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate and the like.
(Xiii) Nitrogen-containing polymerizable unsaturated monomer: For example, (meth) acrylonitrile, (meth) acrylamide, methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, 2- (methacryloyloxy) ethyltrimethylammonium chloride, glycidyl (meth) ) Adducts of acrylates and amines.
(Xiv) A polymerizable unsaturated monomer having at least two polymerizable unsaturated groups in one molecule: for example, allyl (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and the like.
(Xv) Epoxy group-containing polymerizable unsaturated monomer: For example, glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) ) Acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate, allyl glycidyl ether and the like.
(Xvi) (meth) acrylate having a polyoxyethylene chain whose molecular end is an alkoxy group.
(Xvii) Polymerizable unsaturated monomer having a sulfonic acid group: For example, 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl (meth) acrylate, allylsulfonic acid, 4-styrenesulfonic acid, etc .; Sodium salt and ammonium salt.
(Xviii) polymerizable unsaturated monomer having an ultraviolet-absorbing functional group: for example, 2-hydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2-hydroxy-4- (3-acryloyloxy-2) -Hydroxypropoxy) benzophenone, 2,2'-dihydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2,2'-dihydroxy-4- (3-acryloyloxy-2-hydroxypropoxy) benzophenone, 2- (2′-hydroxy-5′-methacryloyloxyethylphenyl) -2H-benzotriazole and the like.
(Xix) Light-stable polymerizable unsaturated monomer: For example, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloyloxy-2,2,6, 6-tetramethylpiperidine, 4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6 , 6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6 6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2 6,6-tetramethylpiperidine and the like.
(Xx) Polymerizable unsaturated monomer having a carbonyl group: For example, acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formylstyrene, vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl Methyl ketone, vinyl ethyl ketone, vinyl butyl ketone) and the like.
(Xxi) Polymerizable unsaturated monomer having an acid anhydride group: For example, maleic anhydride, itaconic anhydride, citraconic anhydride and the like.

  Especially, it is preferable that another polymerizable unsaturated monomer (m-3) contains the said hydroxyl-containing polymerizable unsaturated monomer (xi) as at least one part from a viewpoint of coating workability | operativity. Examples of the hydroxyl group-containing polymerizable unsaturated monomer (xi) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. 2-Hydroxyethyl (meth) acrylate is more preferable.

  When the other polymerizable unsaturated monomer (m-3) contains the hydroxyl group-containing polymerizable unsaturated monomer (xi), the content of the hydroxyl group-containing polymerizable unsaturated monomer (xi) depends on the monomer component (m 5) to 79% by mass, preferably 10 to 57% by mass, and more preferably 15 to 40% by mass.

In the monomer component (m), the content ratio of the macromonomer (m-1), the polymerizable unsaturated monomer (m-2) having a nonionic hydrophilic group, and the other polymerizable unsaturated monomer (m-3) is In general, from the viewpoint of the paint thinning suppression effect and the finish of the coating film to be formed, it is suitable to be within the following range based on the total mass of the monomer component (m).
Macromonomer (m-1): 1 to 29% by mass, preferably 3 to 20% by mass
Total mass of polymerizable unsaturated monomer (m-2) having a nonionic hydrophilic group: 20 to 99 mass%, preferably 40 to 97 mass%
Other polymerizable unsaturated monomer (m-3): 0 to 79% by mass, preferably 5 to 57% by mass.

  The copolymer (A) is usually a graft polymer having a main chain and a side chain, and the macromonomer (m-1) forms a side chain portion and has a nonionic hydrophilic group. The unsaturated monomer (m-2) and other polymerizable unsaturated monomer (m-3) form the main chain portion.

  The copolymer (A) is composed of the macromonomer (m-1), a polymerizable unsaturated monomer (m-2) having a nonionic hydrophilic group, and other polymerizable unsaturated compounds blended as necessary. Manufacture by copolymerizing the monomer component (m) comprising the monomer (m-3) by a method known per se, for example, a solution polymerization method in an organic solvent, an emulsion polymerization method in water, or the like. Can do. Among these, a solution polymerization method that can be carried out by a relatively easy operation is preferable.

  Examples of the polymerization initiator used when copolymerizing the monomer component (m) include benzoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, cumene hydroperoxide, tert-butyl peroxide, Di-tert-amyl peroxide, tert-butyl peroxylaurate, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxyacetate, diisopropylbenzene hydroperoxide, tert-butyl peroxy-2-ethylhexanoate, etc. Organic peroxides; azobisisobutyronitrile, azobis (2,4-dimethylvaleronitrile), azobis (2-methylpropiononitrile), azobis (2-methylbutyronitrile), 4 4'-azobis (4-cyanobutanoic acid), dimethylazobis (2-methylpropionate), azobis [2-methyl-N- (2-hydroxyethyl) -propionamide], azobis {2-methyl-N- Azo compounds such as [2- (1-hydroxybutyl)]-propionamide}; persulfates such as potassium persulfate, ammonium persulfate, sodium persulfate, and the like. These polymerization initiators can be used alone or in combination of two or more. Moreover, it is good also as a redox initiator by using reducing agents, such as saccharide | sugar, sodium formaldehyde sulfoxylate, and an iron complex, for example as needed to the said polymerization initiator.

  The usage-amount of the said polymerization initiator is 0.01-5 mass parts normally on the basis of 100 mass parts of total mass of a monomer component (m), Preferably it can be 0.1-3 mass parts. The method for adding the polymerization initiator is not particularly limited, and can be appropriately selected according to the type and amount thereof. For example, it may be included in the monomer mixture or the reaction solvent in advance, or may be added all at once during the polymerization, or may be added dropwise.

  Moreover, as a solvent in the solution polymerization method, an organic solvent that is less likely to cause chain transfer to the solvent and is water-soluble is preferable. Examples of such solvents include ester solvents such as ethylene glycol monomethyl ether acetate and diethylene glycol monobutyl ether acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone; methanol, ethanol, isopropanol, and n-butanol. , Sec-butanol, isobutanol, and other alcohol solvents; 1,4-dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, and other ether solvents; ethylene glycol monomethyl ether, ethylene glycol mono Ethyl ether, ethylene glycol Include glycol ether solvents such as butyl ether, which can be used either alone or in combination of two or more. Of these, ether solvents and glycol ether solvents are preferred.

  The amount of the organic solvent used in the polymerization reaction is usually 500 parts by mass or less, preferably 50 to 400 parts by mass, more preferably 100 to 200 parts by mass, based on 100 parts by mass of the total mass of the monomer components (m). It is preferable to be within the range of parts.

  The weight average molecular weight of the copolymer (A) is 100,000 or more, preferably in the range of 100,000 to 400,000, from the viewpoint of the paint thinning suppression effect.

  In this specification, the number average molecular weight of the macromonomer (m-1) and the weight average molecular weight of the copolymer (A) and the copolymer (B) described later are determined by gel permeation chromatography (GPC). The retention time (retention capacity) measured in this way is a value obtained by converting to the molecular weight of polystyrene by the retention time (retention capacity) of standard polystyrene with a known molecular weight measured under the same conditions.

  The number average molecular weight of the macromonomer (m-1) is “HLC-8120GPC” (trade name, manufactured by Tosoh Corporation) as a gel permeation chromatograph, and “TSKgel G4000HXL” is used as a column. A total of four TSKgel G3000HXL and one TSKgel G2000HXL (trade name, both manufactured by Tosoh Corporation) were used, and a differential refractometer was used as a detector. Mobile phase: tetrahydrofuran, Measurement can be performed under conditions of a measurement temperature: 40 ° C. and a flow rate: 1 mL / min.

  Moreover, the weight average molecular weights of the copolymer (A) and the copolymer (B) are “HLC-8120GPC” (trade name, manufactured by Tosoh Corporation) as a gel permeation chromatograph, Using one TSKgel GMHHR-L (trade name, manufactured by Tosoh Corporation), using a differential refractometer as a detector, mobile phase: dimethylformamide (containing 10 mM of lithium bromide and phosphoric acid, respectively), measurement It can be measured under conditions of temperature: 25 ° C. and flow rate: 1 mL / min.

Copolymer (B)
In the present invention, the copolymer (B) is a copolymer other than the copolymer (A), and is a polymerizable unsaturated monomer component containing 10 to 40% by mass of a polyoxyalkylene chain-containing polymerizable unsaturated monomer. Copolymer having an acid value of 20 to 100 mg KOH / g, preferably 25 to 75 mg KOH / g and a weight average molecular weight of less than 100,000, preferably 10,000 to 50,000. It is a polymer.

  The copolymer (B) is added for the purpose of maintaining a stable dispersion state of colored pigments or the like in the aqueous paint. When the weight average molecular weight exceeds 100,000, the copolymer (B) is used as a pigment dispersion resin. In addition, the pigment dispersibility is lowered, and the viscosity of the dispersion paste is increased, which is not preferable.

  The polymerizable unsaturated monomer having a polyoxyalkylene chain is the same as that described as the polymerizable unsaturated monomer having a polyoxyalkylene chain in the section of the monomer (m-2) in the copolymer (A). Can be used.

  If the amount of the polymerizable unsaturated monomer having a polyoxyalkylene chain is less than 10% by mass, it may cause discoloration of the water-based paint and deterioration of the toning stability, while if it exceeds 40% by mass, the water resistance of the formed coating film decreases. This is not preferable.

  The polymerizable unsaturated monomer component for producing the copolymer (B) may contain another polymerizable unsaturated monomer copolymerizable with the polymerizable unsaturated monomer having a polyoxyalkylene chain.

  Examples of such other polymerizable unsaturated monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso -Butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) ) Acrylate (lauryl (meth) acrylate), tridecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (medium) ) Acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, alkyl such as tricyclodecanyl (meth) acrylate or cycloalkyl (meth) acrylate, etc. Alkyl (meth) acrylates of the following: aromatic ring-containing polymerizable unsaturated monomers such as benzyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) Polymerizable unsaturated monomers having an alkoxysilyl group such as silane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane; Perfluoroalkyl (meth) acrylates such as orobutylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate; polymerizable unsaturated monomers having fluorinated alkyl groups such as fluoroolefins; and photopolymerizable functionalities such as maleimide groups Polymerizable unsaturated monomer having a group; vinyl compounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate and vinyl acetate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3 -Monoesterified product of (meth) acrylic acid such as hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate and a dihydric alcohol having 2 to 8 carbon atoms, the (meth) acrylic acid and 2 to 2 carbon atoms 8 with dihydric alcohol Non-esterified ε-caprolactone modified, N-hydroxymethyl (meth) acrylamide, hydroxyl-containing polymerizable unsaturated monomers such as allyl alcohol; (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, etc. Carboxy group-containing polymerizable unsaturated monomer; 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl acid phosphate, 2-methacryloyloxypropyl acid phosphate, orthophosphoric acid and 2-hydroxyethyl methacrylate A phosphoric acid group-containing monomer such as a reaction product of; a polymerizable unsaturated monomer having an acid anhydride group such as maleic anhydride, itaconic anhydride, citraconic anhydride; 2-acrylamide-2 Methyl propane sulfonic acid, 2-sulfoethyl (meth) acrylate, allyl sulfonic acid, 4-styrene sulfonic acid, etc .; polymerizable unsaturated monomers having sulfonic acid groups such as sodium salt and ammonium salt of these sulfonic acids; allyl (meth) Acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1 , 4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol Rutetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1-trishydroxymethylethanedi (meth) acrylate, 1,1,1-trishydroxymethylethanetri (meth) acrylate, 1,1,1 A polymerizable unsaturated monomer having at least two polymerizable unsaturated groups in one molecule such as trishydroxymethylpropane tri (meth) acrylate, triallyl isocyanurate, diallyl terephthalate, divinylbenzene; (meth) acrylonitrile, (meta ) Acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, adducts of glycidyl (meth) acrylate and amines Nitrogen content such as Polymerizable unsaturated monomer: glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxy Epoxy group-containing polymerizable unsaturated monomers such as cyclohexylpropyl (meth) acrylate and allyl glycidyl ether; Isocyanato group-containing polymerizable compounds such as 2-isocyanatoethyl (meth) acrylate and m-isopropenyl-α, α-dimethylbenzyl isocyanate Unsaturated monomer; (meth) acrylate having polyoxyethylene chain whose molecular terminal is an alkoxy group; acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate , Formyl styrol, vinyl alkyl ketones having 4 to 7 carbon atoms (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone) and the carbonyl-containing polymerizable unsaturated monomers such as. These polymerizable unsaturated monomers can be used alone or in combination of two or more.

  The copolymer (B) preferably has an acid group from the viewpoint of water dispersibility or water solubility of the dispersion paste. Moreover, if the acid value of a copolymer (B) is less than 20 mgKOH / g, it will cause a time-dependent discoloration and a toning stability fall of an aqueous coating material, and if it exceeds 100 mgKOH / g, the water resistance of a coating film will fall and it is unpreferable.

  The acid group-containing monomer used for introducing an acid group into the copolymer (B) is the above monomer (m-3), a carboxyl group-containing polymerizable unsaturated monomer, a phosphate group-containing polymerizable unsaturated monomer. The compounds listed in the description of the acid anhydride group-containing polymerizable unsaturated monomer and the sulfonic acid group-containing polymerizable unsaturated monomer can be used, and these can be used alone or in combination of two or more.

  In the copolymer (B), the polymerization of the polymerizable unsaturated monomer component is suitably performed by a solution polymerization method in an organic solvent using a radical polymerization initiator.

  Examples of the radical polymerization initiator include benzoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, cumene hydroperoxide, tert-butyl peroxide, di-tert-amyl peroxide, and tert-butyl peroxide. Organic peroxides such as oxylaurate, tert-butylperoxyisopropyl carbonate, tert-butylperoxyacetate, diisopropylbenzene hydroperoxide, tert-butylperoxy-2-ethylhexanoate; azobisisobutyronitrile , Azobis (2,4-dimethylvaleronitrile), azobis (2-methylpropiononitrile), azobis (2-methylbutyronitrile), 4,4′-azobis (4-cyanobutane) ), Dimethylazobis (2-methylpropionate), azobis [2-methyl-N- (2-hydroxyethyl) -propionamide], azobis {2-methyl-N- [2- (1-hydroxybutyl) ] -Propionamide} and the like; and persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate. These polymerization initiators can be used alone or in combination of two or more. The blending amount of the radical polymerization initiator is not particularly limited, but is usually 0.1 to 0.1 on the basis of 100 parts by mass of the polymerizable unsaturated monomer mixture for producing the copolymer (B). It is suitable that it is in the range of 10 parts by mass, preferably 0.1 to 8 parts by mass, more preferably 0.1 to 6 parts by mass.

  In addition, a water-soluble organic solvent is preferable as a solvent in the solution polymerization method. Examples of such a solvent include ester solvents such as ethylene glycol monomethyl ether acetate and diethylene glycol monobutyl ether acetate; methyl ethyl ketone, methyl isobutyl ketone, and diisobutyl. Ketone solvents such as ketone and cyclohexanone; alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, sec-butanol and isobutanol; 1,4-dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol dimethyl ether, Ether solvents such as dipropylene glycol dimethyl ether; ethylene glycol monomethyl Ether, ethylene glycol monoethyl ether, glycol monoethyl ether and ethylene glycol monobutyl ether and the like, which can be used either alone or in combination of two or more.

Resin emulsion component (C)
In the present invention, as the resin emulsion component (C), a resin emulsion known per se that has been conventionally used as a binder component for water-based paints can be used. Examples of the resin emulsion component (C) resin include acrylic resin, polyester resin, alkyd resin, polyurethane resin, silicone resin, fluororesin, and epoxy resin. These may be used alone or in combination of two or more. It may be what you did.

  The resin emulsion component (C) is preferably a resin having an ester bond from the viewpoint of the finish of the formed coating film. As the resin having an ester bond, for example, an acrylic resin obtained by polymerizing a monomer mixture containing a polymerizable unsaturated monomer having an ester bond can be suitably used. A water-based coating composition containing a copolymer (A) and a resin emulsion component (C) having an ester bond is a coating film having an appearance with excellent coating workability and excellent finish even under normal temperature drying conditions. The reason for the formation is that the ester bond in the polymerizable unsaturated monomer (a) having an alkyl group having 3 to 24 carbon atoms present in the side chain of the copolymer (A) and the resin emulsion component (C) It is presumed that a high viscosity is developed because a network structure having high affinity with an ester bond and a tighter bond is formed.

  Since the acrylic resin emulsion is generally obtained by dispersing a relatively hydrophobic acrylic resin in an aqueous medium, a coating film excellent in water resistance is formed. In addition, since the copolymer (A) has a hydrophobic side chain, it forms a network structure with the relatively hydrophobic acrylic resin emulsion as described above, and develops a viscosity. It is possible to form a coating film that is good and has an appearance with excellent finish.

  The acrylic resin emulsion is preferably an acrylic resin emulsion imparted with water dispersibility by a surfactant from the viewpoint of the storage stability of the resulting paint. The copolymer (A) has a viscosity characteristic that develops viscosity even in an emulsion resin coating containing a surfactant and decreases with increasing shear rate. An aqueous coating composition containing an acrylic resin emulsion imparted with water dispersibility by an activator has excellent storage stability and coating workability, has an excellent appearance, and has excellent water resistance. The coating film which has can be formed.

  The acrylic resin emulsion imparted with water dispersibility by the surfactant is preferably obtained by, for example, emulsion polymerization using a surfactant or miniemulsion polymerization using a surfactant. is there.

Specific examples of the polymerizable unsaturated monomer for producing the acrylic resin emulsion are listed below.
(I) Alkyl or cycloalkyl (meth) acrylate: For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) Acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) Acrylate, cyclododecyl (meth) acrylate, tricyclodecanyl (meth) acrylate.
(Ii) Polymerizable unsaturated monomer having an isobornyl group: for example, isobornyl (meth) acrylate.
(Iii) Polymerizable unsaturated monomer having an adamantyl group: for example, adamantyl (meth) acrylate and the like.
(Iv) Polymerizable unsaturated monomer having a tricyclodecenyl group: For example, tricyclodecenyl (meth) acrylate and the like.
(V) Aromatic ring-containing polymerizable unsaturated monomer: For example, benzyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene and the like.
(Vi) Hydroxyl group-containing polymerizable unsaturated monomer: For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. Monoesterified product of (meth) acrylic acid and C2-8 dihydric alcohol; ε-caprolactone modified product of monoesterified product of (meth) acrylic acid and C2-8 dihydric alcohol; allyl Alcohol etc.
(Vii) Carboxy group-containing polymerizable unsaturated monomer: For example, (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate and the like.
(Viii) Polymerizable unsaturated monomer having a sulfonic acid group: For example, 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl (meth) acrylate, allylsulfonic acid, 4-styrenesulfonic acid, etc .; Sodium salt and ammonium salt.
(Ix) Phosphoric acid group-containing polymerizable unsaturated monomer: For example, 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl acid phosphate, 2-methacryloyloxypropyl acid phosphate and the like.
(X) Polymerizable unsaturated monomer having an acid anhydride group: For example, maleic anhydride, itaconic anhydride, citraconic anhydride and the like.
(Xi) Nitrogen-containing polymerizable unsaturated monomer: For example, (meth) acrylonitrile, (meth) acrylamide, methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, 2- (methacryloyloxy) ethyltrimethylammonium chloride, glycidyl (meth) ) Adducts of acrylates and amines.
(Xii) Carbonyl group-containing polymerizable unsaturated monomer: (meth) acrolein, formylstyrene, vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone), acetoacetoxyethyl (Meth) acrylate, acetoacetoxyallyl ester, diacetone (meth) acrylamide and the like.
(Xiii) Fatty acid-modified polymerizable unsaturated monomer: for example, fish oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, sesame oil fatty acid, poppy oil fatty acid, eno oil fatty acid, hemp oil fatty acid, grape nucleus Dry fatty acids such as 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, hydienoic acid fatty acids, and epoxy groups such as semi-drying oil fatty acids and glycidyl (meth) acrylate Reaction products with contained polymerizable unsaturated monomers.
(Xix) A polymerizable unsaturated monomer having at least two polymerizable unsaturated groups in one molecule: for example, allyl (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene Glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1 , 6-hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1-trishydroxymethylethanedi (meth) Acrylate, 1,1,1-trishydroxymethylethane tri (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate, triallyl isocyanurate, diallyl terephthalate, divinylbenzene and the like.
(Xv) Polymerizable unsaturated monomer having an ultraviolet absorbing functional group: For example, 2-hydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2-hydroxy-4- (3-acryloyloxy-2) -Hydroxypropoxy) benzophenone, 2,2'-dihydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2,2'dihydroxy-4- (3-acryloyloxy-2-hydroxypropoxy) benzophenone, 2, -(2'-hydroxy-5'-methacryloyloxyethylphenyl) -2H-benzotriazole and the like.
(Xvi) Light-stable polymerizable unsaturated monomer: For example, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloyloxy-2,2,6, 6-tetramethylpiperidine, 4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6 , 6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6 6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2 It can be used 6,6-tetramethylpiperidine and the like. These polymerizable unsaturated monomers can be used alone or in combination of two or more.

  In the acrylic resin emulsion, when a hydroxyl group-containing polymerizable unsaturated monomer is used as one component of the polymerizable unsaturated monomer, the viscosity development of the resulting aqueous coating composition is improved, and the acrylic resin emulsion in the aqueous medium is improved. There is an effect of improving stability. Examples of the hydroxyl group-containing polymerizable unsaturated monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like ( Monoesterified product of (meth) acrylic acid and C2-C8 dihydric alcohol; ε-caprolactone modified product of monoesterified product of (meth) acrylic acid and C2-C8 dihydric alcohol; N- Examples thereof include hydroxymethyl (meth) acrylamide, allyl alcohol, and (meth) acrylate having a polyoxyethylene chain whose molecular end is a hydroxyl group. These monomers can be used alone or in combination of two or more. As the hydroxyl group-containing polymerizable unsaturated monomer, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, or the like is used. preferable.

  In addition, it is preferable to use a hydrophobic polymerizable unsaturated monomer as one component of the polymerizable unsaturated monomer, since the coating workability of the paint of the present invention is improved and good finish is obtained.

  The hydrophobic polymerizable unsaturated monomer is a polymerizable unsaturated monomer having a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 6 or more carbon atoms, preferably 6 to 18 carbon atoms. Monomers having a hydrophilic group such as a polymerizable unsaturated monomer are excluded.

  Examples of the monomer include n-hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth). ) Alkyls such as acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, tricyclodecanyl (meth) acrylate Or cycloalkyl (meth) acrylate; polymerizable unsaturated compound having an isobornyl group such as isobornyl (meth) acrylate; adamant such as adamantyl (meth) acrylate Polymerizable unsaturated compound having an Le group; benzyl (meth) acrylate, styrene, alpha-methyl styrene, can be mentioned aromatic ring-containing polymerizable unsaturated monomers such as vinyl toluene. These monomers can be used alone or in combination of two or more.

  In addition, from the viewpoint of improving the finish of the resulting coating film, as the hydrophobic polymerizable unsaturated monomer, a polymerizable unsaturated monomer having an alkyl group having 6 to 18 carbon atoms and / or an aromatic ring-containing polymerizable unsaturated monomer. It is preferable to use a monomer. In particular, it is more preferable to use 2-ethylhexyl acrylate.

  Moreover, the stability in the aqueous medium of the acrylic resin emulsion obtained when the said polymerizable unsaturated monomer contains a carboxyl group-containing polymerizable unsaturated monomer as a part of the component can be ensured.

  As the carboxyl group-containing polymerizable unsaturated monomer, it is preferable to use acrylic acid and / or methacrylic acid.

  The emulsion polymerization for preparing the acrylic resin emulsion can be performed by a conventionally known method. For example, it can be carried out by emulsion polymerization of a polymerizable unsaturated monomer mixture using a polymerization initiator in the presence of a surfactant.

  In addition, when polymerizing a hydrophobic monomer that is difficult to emulsion-polymerize, such as a fatty acid-modified polymerizable unsaturated monomer, as the polymerizable unsaturated monomer, the fatty acid-modified polymerizable unsaturated monomer and other polymerizable unsaturated monomers and necessary Accordingly, a monomer mixture containing a surfactant is finely dispersed in an aqueous medium so that the average particle size is 500 nm or less, the average particle size is 50 to 500 nm, particularly 75 to 400 nm, more particularly 100 to 250 nm, The obtained emulsion can be polymerized by a so-called miniemulsion polymerization method.

  As the surfactant, an anionic surfactant and a nonionic surfactant are suitable. Examples of the anionic surfactant include sodium salts and ammonium salts such as alkylsulfonic acid, alkylbenzenesulfonic acid, and alkylphosphoric acid. Examples of nonionic surfactants include polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene phenyl ether, polyoxyethylene nonyl phenyl ether, Polyoxyethylene octyl phenyl ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate, polyoxyethylene sorbitan monolaurate, etc. Is mentioned.

  Also, a polyoxyalkylene group-containing anionic surfactant having an anionic group and a polyoxyalkylene group such as a polyoxyethylene group or a polyoxypropylene group in one molecule; an anionic group and radical polymerizability in one molecule A reactive anionic surfactant having an unsaturated group can also be used. Among these, it is preferable to use a polyoxyalkylene group-containing anionic surfactant.

  Examples of the reactive anionic surfactant include sodium salts of sulfonic acid compounds having radically polymerizable unsaturated groups such as allyl group, methallyl group, (meth) acryloyl group, propenyl group, butenyl group, An ammonium salt etc. can be mentioned.

  The amount of the surfactant used is preferably about 0.1 to 15% by mass, more preferably about 0.5 to 10% by mass, based on the total amount of all polymerizable unsaturated monomers used. About 5 mass% is still more preferable.

  Examples of the polymerization initiator include benzoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, cumene hydroperoxide, tert-butyl peroxide, di-tert-amyl peroxide, and tert-butyl peroxide. Organic peroxides such as laurate, tert-butylperoxyisopropyl carbonate, tert-butylperoxyacetate, diisopropylbenzene hydroperoxide, tert-butylperoxy-2-ethylhexanoate; azobisisobutyronitrile, Azobis (2,4-dimethylvaleronitrile), azobis (2-methylpropiononitrile), azobis (2-methylbutyronitrile), 4,4′-azobis (4-cyanobutanoic acid), Methylazobis (2-methylpropionate), azobis [2-methyl-N- (2-hydroxyethyl) -propionamide], azobis {2-methyl-N- [2- (1-hydroxybutyl)]-propionamide } And persulfates such as potassium persulfate, ammonium persulfate and sodium persulfate. These polymerization initiators can be used singly or in combination of two or more. Moreover, it is good also as a redox initiator by using together with reducing agents, such as saccharide | sugar, sodium formaldehyde sulfoxylate, and an iron complex, as needed to the said polymerization initiator.

  In general, the amount of the polymerization initiator used is preferably about 0.1 to 5% by mass, more preferably about 0.2 to 3% by mass, based on the total mass of all monomers used.

  Further, the polymerizable unsaturated monomer mixture can be dropped as it is, but it is desirable to drop the polymerizable unsaturated monomer mixture as a monomer emulsion obtained by dispersing the polymerizable unsaturated monomer mixture in an aqueous medium using a surfactant. .

  The method for adding the polymerization initiator is not particularly limited, and can be appropriately selected according to the type and amount thereof. For example, it may be previously contained in a polymerizable unsaturated monomer mixture, a monomer emulsion, or an aqueous medium in a reaction vessel, or may be added all at once during the polymerization, or may be added dropwise.

  On the other hand, the method for adding the surfactant is not particularly limited, and it may be contained in the polymerizable unsaturated monomer and the aqueous medium to form a monomer emulsion, or may be contained in the aqueous medium in the reaction vessel.

  As the acrylic resin emulsion thus obtained, even if it is a single-layer acrylic resin emulsion obtained by polymerizing a monomer mixture comprising a polymerizable unsaturated unsaturated monomer in one step, the monomer mixture having a different composition is divided into two steps. It may be a core-shell type acrylic resin emulsion obtained by polymerizing separately.

  Further, in order to improve the mechanical stability of the particles of the acrylic resin emulsion, when the acrylic resin emulsion has an acid group such as a carboxyl group, it is desirable to neutralize the acid group with a neutralizing agent. The neutralizing agent is not particularly limited as long as it can neutralize an acid group. For example, sodium hydroxide, potassium hydroxide, trimethylamine, 2- (dimethylamino) ethanol, 2-amino-2-methyl- Examples include 1-propanol, triethylamine, and aqueous ammonia. These neutralizing agents are desirably used in such an amount that the pH of the aqueous dispersion of the water-dispersible acrylic resin after neutralization is about 6.5 to 9.0.

Aqueous paint composition The aqueous paint composition of the present invention comprises the copolymer (A), the copolymer (B), and the resin emulsion component (C).

  In the aqueous coating composition according to the present invention, the contents of the copolymer (A) and the copolymer (B) are the storage stability of the coating, the appearance of the coating film formed, the coating film performance (water resistance, etc. ) And the like, the content of the copolymer (A) is 0.01 to 10 parts by mass, preferably 0.1 to 8 parts by mass, based on 100 parts by mass of the resin solid content of the resin emulsion component (C). The content of the copolymer (B) is within the range of 0.01 to 10 parts by mass, preferably 0.1 to 8 parts by mass, and more preferably 0.2 to 5 parts by mass. Is preferred.

  Moreover, it is suitable that content of the resin emulsion component (C) is 80% by mass or more, particularly 90% by mass or more in the resin solid content contained in the aqueous coating composition.

  The aqueous coating composition of the present invention has a good finish even with a single-layer finish, and can be used as a single-layer top coat because it forms a coating film with excellent performance. It can also be used as a top coat or as a base coat for undercoating.

  If necessary, the aqueous coating composition of the present invention may further include a color pigment, an extender pigment, a bright pigment, an organic solvent, a curing agent, a curing catalyst, an ultraviolet absorber, a light stabilizer, a pigment dispersant, and an antifoaming agent. , Paint additives such as plasticizers, surface conditioners and anti-settling agents can be contained.

  Among these, conventionally known pigments can be used without limitation, such as titanium oxide, zinc white, iron oxide, carbon black, molybdenum red, Prussian blue, cobalt blue, azo pigments, phthalocyanine pigments. Quinacridone pigments, isoindoline pigments, selenium pigments, perylene pigments, dioxazine pigments, diketopyrrolopyrrole pigments, and the like. These color pigments can be used alone or in combination of two or more.

  As the extender pigment, conventionally known pigments can be used without limitation, and examples thereof include talc, clay, kaolin, barita, barium sulfate, barium carbonate, calcium carbonate, silica, and alumina white.

  When the aqueous coating composition of the present invention contains a pigment, the blending amount of the pigment can be appropriately adjusted according to the type of pigment and the application of the coating.

  Although there is no restriction | limiting in the addition method of the said copolymer (B) in this invention, For example, it can be used as a pigment dispersion resin for disperse | distributing the pigment contained in the pigment dispersion paste for a paint or a paint toning.

Method for Forming Coating Film The aqueous coating composition of the present invention can form a coating film having an excellent appearance by coating on various objects.

The article to be coated to which the aqueous coating composition of the present invention is applied is not particularly limited, but a building is suitable.

  Specific examples of the building as the object to be coated include a wall inside and outside the building, a ceiling, a roof, a pillar inside the building, a pipe, a door, and the like.

  The material of these objects to be coated is not particularly limited. For example, surfaces of base materials such as gypsum board, concrete wall, mortar wall, slate board, PC board, ALC board, cement calcium silicate board, wood, stone, plastic molding, metal workpiece, etc. Acrylic resin-based, acrylic urethane resin-based, polyurethane resin-based, fluororesin-based, silicon acrylic resin-based, vinyl acetate resin-based, epoxy resin-based coating surface, polyvinyl chloride, polyolefin, paper, cloth, etc. Can be mentioned.

Coating Film Forming Method In the coating film forming method of the aqueous coating composition of the present invention, the desired finish can be obtained by either smooth finishing or uneven finishing, and it can be carried out using various coating means. For example, it can be appropriately selected depending on the use of the substrate such as a roller, air spray, airless spray, lysine gun, universal gun, brush, roll coater, and the like. Although the formed coating film can be dried under conditions of room temperature drying, heat drying or forced drying can be performed as necessary.

  Hereinafter, the present invention will be described more specifically with reference to production examples, examples and comparative examples. However, the present invention is not limited to these. In each example, “parts” and “%” are based on mass unless otherwise specified.

Production Example 1 of Macromonomer (m-1)
In a reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, nitrogen gas introduction tube and dropping device, 16 parts of ethylene glycol monobutyl ether and 2,4-diphenyl-4-methyl-1-pentene (hereinafter referred to as “ 9.0 parts) (which may be abbreviated as “MSD”) was charged, nitrogen gas was passed through the gas phase, and the temperature was raised to 160 ° C. while stirring. When the temperature reached 160 ° C., a mixed solution consisting of 50 parts of n-butyl methacrylate, 50 parts of 2-hydroxyethyl methacrylate and 7 parts of di-tert-amyl peroxide was added dropwise over 3 hours and stirred at the same temperature for 2 hours. Subsequently, it was cooled to 30 ° C. and diluted with ethylene glycol monobutyl ether to obtain a macromonomer solution (m-1-1) having a solid content of 65%. The resulting macromonomer had a hydroxyl value of 216 mg KOH / g and a number average molecular weight of 2,500. Moreover, according to the analysis by proton NMR, 97% or more of the ethylenically unsaturated groups derived from MSD were present at the end of the polymer chain, and 2% had disappeared.

  In the above proton NMR analysis, deuterated chloroform was used as a solvent, the peaks (4.8 ppm, 5.1 ppm) based on the protons of the unsaturated group of MSD before and after the polymerization reaction, the ethylenic properties of the macromonomer chain ends. After measuring the peak of the unsaturated group proton (5.0 ppm, 5.2 ppm) and the peak of the aromatic proton derived from MSD (7.2 ppm), the aromatic proton derived from the MSD (7.2 ppm) Was assumed to be unchanged before and after the polymerization reaction, and based on this, each unsaturated group (unreacted, macromonomer chain end, disappearance) was quantified.

Production Examples 2-8
The macromonomer solutions (m-1-2) to (m-1-8) having a solid content of 65% were obtained by synthesizing in the same manner as in Production Example 1 except that the monomer components were blended as shown in Table 1 below. .

  In Production Example 4, the macromonomer solution (m-1-4) was obtained in the same manner as in Production Example 1, except that the mixture to be dropped was blended as shown in Table 1 below and the reaction temperature was 120 ° C. .

Production of copolymer (A) solution Production Example 9
10.8 parts of the macromonomer solution (m-1-1) obtained in Production Example 1 was added to a reaction vessel equipped with a thermometer, a thermostat, a stirring device, a reflux condenser, a nitrogen gas inlet tube and two dropping devices (solid) 7.0 parts), 20 parts of ethylene glycol monobutyl ether and 30 parts of diethylene glycol monoethyl ether acetate were added, and the temperature was raised to 85 ° C. while blowing nitrogen gas into the liquid. Next, in a reaction vessel maintained at the same temperature, 32.6 parts of N, N-dimethylacrylamide, 32.6 parts of N-isopropylacrylamide, 27.9 parts of 2-hydroxyethyl acrylate, 10 parts of ethylene glycol monobutyl ether and diethylene glycol A mixture of 40 parts of monoethyl ether acetate, 0.15 part of “Perbutyl O” (trade name, manufactured by NOF Corporation, polymerization initiator, tert-butylperoxy-2-ethylhexanoate) and ethylene glycol mono A mixed solution composed of 20 parts of butyl ether was added dropwise to the reaction vessel simultaneously over 4 hours, and after completion of the addition, the mixture was aged by stirring at the same temperature for 2 hours. Then, in a reaction vessel maintained at the same temperature, a mixed solution consisting of 0.3 part of 2,2′-azobis (2,4-dimethylvaleronitrile) and 15 parts of ethylene glycol monobutyl ether was dropped over 1 hour, After completion of the dropping, the mixture was aged by stirring for 1 hour at the same temperature. Subsequently, it cooled to 30 degreeC, adding ethylene glycol monobutyl ether, and obtained the copolymer solution of 35% of solid content. The weight average molecular weight of the obtained copolymer was 230,000. To the obtained copolymer solution, 382 parts of deionized water was added to obtain a copolymer solution (A-1) having a solid content of 15%.

Production Examples 10 to 18
In Production Example 9, copolymer solutions (A-2) to (A-10) having a solid content of 15% were obtained in the same manner as Production Example 9, except that the monomer composition was as shown in Table 2 below. .

Production and production example 19 of copolymer (B) solution
A reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen gas inlet tube and dropping device was charged with 30 parts of ethylene glycol monobutyl ether, and nitrogen gas was bubbled into the gas phase, and the temperature was kept at 95 ° C while stirring. The temperature rose. When the temperature reaches 95 ° C., 5 parts of styrene, 35 parts of methyl methacrylate, 35 parts of n-butyl acrylate, 5 parts of acrylic acid, methoxypolyethylene glycol monomethacrylate having a solid content concentration of 50% (may be referred to as “MPEG2000MA”) A mixed solution consisting of 40 parts and 4 parts of ethylene glycol monobutyl ether and 3.5 parts of 2,2-azobis (2-methylbutyronitrile) was added dropwise over 4 hours and stirred at the same temperature for 30 minutes. Subsequently, at 95 ° C., a mixed solution of 0.5 part of 2-azobis (2-methylbutyronitrile) and 2 parts of ethylene glycol monobutyl ether was added dropwise over 1 hour, followed by stirring at the same temperature for 1 hour. Thereafter, ethylene glycol monobutyl ether was added to a solid content of 60%, and the mixture was cooled to 30 ° C. After adding 5.6 parts of triethylamine to this resin solution and stirring for 15 minutes, deionized water was added with stirring to obtain a copolymer solution (B-1) having a solid content of 20%. The resin acid value of the obtained copolymer was 39.0 mgKOH / g, and the weight average molecular weight was 3.7 × 10 ⁴ .

Production Examples 20 to 26
In the above Production Example 19, the copolymer solution (B-2) to the copolymer solution (B-8) were prepared in the same manner as in Production Example 19 except that the monomer composition and initiator amount to be dropped were as shown in Table 3. )

Production and production example 27 of acrylic resin emulsion
In a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer and a dropping funnel, 28.5 parts of deionized water, “Newcol 707SF” (trade name, anionic emulsifier, solid content 30%, manufactured by Nippon Emulsifier Co., Ltd.) 12 parts were added and maintained at 80 ° C. after nitrogen substitution. To this, 0.1 part of ammonium persulfate was added, and 20 minutes after the addition, a pre-emulsion obtained by emulsifying the following composition was added dropwise over 4 hours.
Deionized water 36.1 parts Styrene 15 parts Methyl methacrylate 46 parts n-Butyl acrylate 18.5 parts 2-Ethylhexyl acrylate 18.5 parts 2-Hydroxyethyl acrylate 1.0 part Acrylic acid 1.0 part 30% Newcol 707SF 6 .6 parts ammonium persulfate 0.2 parts after completion of dropping, maintained at 80 ° C. for 2.5 hours. Thereafter, the temperature was lowered to 40 ° C. or lower while adding deionized water, and the pH was adjusted to 7 to 8 with aqueous ammonia to obtain an acrylic resin emulsion (C-1) having a solid content concentration of 50%.

Production Examples 28-30
In Production Example 17, acrylic resin emulsions (C-2) to (C-4) having a solid concentration of 50% were obtained in the same manner as Production Example 27 except that the pre-emulsion composition was changed to Table 4.
Production Example 31
In a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, and a dropping funnel, 28.5 parts of deionized water, “Newcol 707SF” (manufactured by Nippon Emulsifier Co., Ltd., an anionic surfactant having a polyoxyethylene chain, nonvolatile content 30 %) 0.12 part was added and kept at 80 ° C. after nitrogen substitution.
2% of the pre-emulsion for the core obtained by emulsifying the following composition and 0.4 part of ammonium persulfate and 10.4 part of 25% of the initiator aqueous solution dissolved in 10 parts of deionized water are added to this. Then, 20 minutes after the addition, the remainder of the core pre-emulsion and 50% of the initiator aqueous solution were added dropwise over 170 minutes.
≪Pre-emulsion for core≫
Deionized water 25.3 parts Styrene 10.5 parts Methyl methacrylate 21.0 parts n-Butyl acrylate 18.6 parts 2-Ethylhexyl acrylate 18.6 parts Hydroxyethyl acrylate 0.7 parts Acrylic acid 0.7 parts "Newcol 707SF 4.6 parts ammonium persulfate 0.14 parts After completion of dropping, this was further maintained at 80 ° C. for 30 minutes, and then the pre-emulsion for shell formed into the following composition and 25% of the above aqueous initiator solution Was added dropwise over 70 minutes.
≪Pre-emulsion for shell≫
Deionized water 10.8 parts Styrene 2.0 parts Methyl methacrylate 18.0 parts n-Butyl acrylate 3.5 parts 2-Ethylhexyl acrylate 3.5 parts Hydroxyethyl acrylate 0.3 part Acrylic acid 0.3 part "Newcol 707SF After the completion of dropwise addition of 2.0 parts of ammonium persulfate (0.06 parts), this was further maintained at 80 ° C. for 2 hours, and then cooled to 40 ° C. or lower while adding deionized water. Next, the pH was adjusted to 8-9 with aqueous ammonia to obtain a core-shell type resin emulsion (C-5) having a solid content concentration of 50%.

Production Example 32
An acrylic resin emulsion (C-6) having a solid content concentration of 50% was obtained in the same manner as in Production Example 31, except that the pre-emulsion composition for core and shell was as shown in Table 4 in Production Example 31.

Production Example 33
The following components are put into a glass beaker, stirred at 2000 rpm for 15 minutes with a disper to produce a preliminary emulsion, and then the preliminary emulsion is pressurized at 120 MPa with a high-pressure emulsifier that applies high-pressure energy to collide the fluids. By processing, a monomer emulsion having an average particle size of dispersed particles of 190 nm was obtained.
≪Monomer emulsion composition≫
Deionized water 84.3 parts Fatty acid-modified polymerizable unsaturated monomer (Note 1) 30.0 parts Styrene 15 parts Methyl methacrylate 48.0 parts 2-Ethylhexyl acrylate 5.0 parts 2-Hydroxyethyl acrylate 1.0 part Acrylic acid 1.0 part “Newcol 707SF” 8.0 parts The monomer emulsion was then transferred to a flask. Thereafter, the temperature was raised to 82 ° C., and an initiator aqueous solution in which 0.5 part of ammonium persulfate was dissolved in 6.0 parts of deionized water was dropped over 1.5 hours, and the mixture was stirred for 1 hour while maintaining the temperature. . Thereafter, an initiator aqueous solution in which 0.25 parts of ammonium persulfate was dissolved in 3.0 parts of deionized water was added to the flask over 30 minutes, stirred for 2 hours while maintaining the temperature, and then cooled to 40 ° C. The pH was adjusted to 8.0 with ammonia water to obtain a fatty acid-modified acrylic resin emulsion (C-7) having a solid content concentration of 48% and an average particle size of the dispersed resin of 185 nm.
(Note 1): A reaction product obtained by putting 280 parts of linseed oil fatty acid and 142 parts of glycidyl methacrylate in a reaction vessel and reacting with stirring at a reaction temperature of 140 ° C. for 5 hours.

Production of white pigment paste Production Example 34
The following composition was blended in a stirring and mixing vessel and mixed uniformly to obtain a white pigment paste.
Water 893 parts Ethylene glycol 96 parts Sura-off 72N (Nippon Envirochemicals, Inc., preservative) 4.8 parts Nopco Santo K (manufactured by San Nopco, pigment dispersant) 24 parts SN deformer A-63 (manufactured by San Nopco, defoamed) Agent) 38 parts titanium white 1056 parts.

Production of water-based colored paint toned with colored pigment dispersion paste Example 1
120 parts of white pigment paste obtained in Production Example 34, 200 parts of acrylic resin emulsion (C-1) (100 parts of solids), 1.26 parts of copolymer solution (A-1) (solids 0) 19 parts), 12 parts of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate were added and mixed uniformly to obtain an aqueous white paint.
On the other hand, the copolymer solution (B-1), clean water, SN deformer A-63, and slough-off 72N were mixed in another mixing vessel at the blending ratio described in the colored pigment paste part of Table 5, and this mixed solution Ocher pigment “TAROX LL-50” (trade name, manufactured by Titanium Industry Co., Ltd.) was gradually added to the mixture, and the whole amount was added and stirred for 15 minutes to obtain a pre-kneaded dispersion. Next, this pre-kneaded dispersion was shaken over 1 hour with a paint shaker to obtain a colored pigment paste. 56.0 parts of the color pigment paste thus obtained was added to the aqueous white paint and mixed by stirring to obtain a cream-colored aqueous colored paint (X-1).

Examples 2 to 15 and Comparative Examples 1 to 11
In Example 1, water-based colored paints (X-2) to (X-26) were obtained in the same manner as in Example 1 except that the composition was as shown in Table 5 below.

The cream-based aqueous colored paints toned with the respective aqueous white paints and yellow pastes obtained in the above Examples and Comparative Examples were subjected to the following evaluation test. The results are shown in Table 5.
In addition, the numerical value of Table 5 is an actual mixing | blending display, and the numerical value in a parenthesis is solid content display.

(Note 2) “Primal SCT-275”: manufactured by Rohm and Haas, polyether polyurethane (Note 3) “Adecanol UH-530”: trade name, manufactured by ADEKA, polyether polyol-based polyurethane (Note 4) “SMA 1440H” ": Sartomer, half-esterified product of styrene-maleic anhydride copolymer (* 1) Initial viscosity of aqueous white paint The temperature of each aqueous white paint was adjusted to 20 ° C and measured using a Stormer viscometer. value.
(* 2) Viscosity retention The temperature of the water-based colored paint obtained by adding the color pigment paste to each water-based white paint is adjusted to 20 ° C. and measured with a Stormer viscometer (after the color pigment-dispersed paste is added). Viscosity / water-based white paint viscosity) × 100. The lower this value is, the more the tendency of the paint to become thinner is worse, and the workability of the paint is deteriorated and the color is changed.
(* 3) Pigment dispersibility Each colored pigment paste was measured with a centrifugal particle size distribution analyzer “BI-DCP”.
A: 0.25 ± 0.025 micron ○: 0.30 ± 0.025 micron Δ: 0.35 ± 0.025 micron (* 4) Water resistance test 70 × 150 × 0.8 mm (Kansai paint Co., Ltd., epoxy-amine anticorrosive undercoat) was painted what was left for 24 hours and the coated plate, painted each aqueous colored coating on the one surface of the coating amount 120 g / m ² by air spraying did. After drying for 1 week under the conditions of 20 ° C and 75% relative humidity, the paint is further applied by air spray at a coating amount of 120 g / m ² and dried for 2 hours under the conditions of 20 ° C and 75% relative humidity. Then, the test plate was half-immersed in water at 20 ° C., and after 1 hour, the test plate was pulled up and the coated surface was visually evaluated.
A: No change at all,
◯: Slightly minute bulge is observed,
△: A considerable amount of swelling is observed,
X: There is blistering on the entire surface.

Claims (8)

An aqueous coating composition comprising a copolymer (A), a copolymer (B) and a resin emulsion component (C) (excluding the copolymer (A)), wherein the copolymer (A) is (m -1) A polymerizable unsaturated monomer (a) having 3 to 24 carbon atoms, which is a monoesterified product of (meth) acrylic acid and a monohydric alcohol having 3 to 24 carbon atoms , is used in an amount of 5 to 100. A macromonomer having a number average molecular weight of 1,000 to 7,000 having a polymer chain and a polymerizable unsaturated group obtained by polymerizing the monomer component (I) contained by mass (m−2), ) A polymerizable unsaturated monomer having at least one nonionic hydrophilic group selected from the group consisting of N-substituted (meth) acrylamide, a polymerizable unsaturated monomer having a polyoxyalkylene chain, and N-vinyl-2-pyrrolidone -And (m-3) is a copolymer having a weight average molecular weight of 100,000 or more obtained by copolymerizing the monomer component (m) composed of other polymerizable unsaturated monomers, and the copolymer (B) However, the acid value obtained by copolymerizing a polymerizable unsaturated monomer component containing 10 to 40% by mass of a polymerizable unsaturated monomer having a polyoxyalkylene chain is in the range of 20 to 100 mg KOH / g, and the weight average molecular weight is 100. A water-based coating composition characterized by being a copolymer of less than 1,000. The aqueous coating composition according to claim 1, wherein the polymerizable unsaturated monomer (m-2) having a nonionic hydrophilic group is N-substituted (meth) acrylamide. The copolymerization ratio of (m-1), (m-2) and (m-3) in the copolymer (A) is such that (m-1) is 1 to 29% by mass and (m-2) is 20 to 20%. The water-based coating composition according to claim 1 or 2, wherein 99% by mass and (m-3) are in the range of more than 0 to 79% by mass. The water-based paint composition according to claims 1 to 3, wherein the monomer component (I) contains, as at least a part thereof, 5 to 60% by mass of a hydroxyl group-containing polymerizable unsaturated monomer based on the total mass of the monomer component (I). object. The water-based paint composition according to claim 1, wherein the resin emulsion component (C) comprises an acrylic resin emulsion, and the acrylic resin emulsion is provided with water dispersibility by a surfactant. The content of the copolymer (A) and the copolymer (B) is 0.01 to 10 parts by mass (B) based on 100 parts by mass of the resin solid content of the resin emulsion component (C). Is in a range of 0.01 to 10 parts by mass. The coating-film formation method which forms a coating film in the to-be-coated article using the water-based coating composition of Claims 1-6. A coated article coated by the coating film forming method according to claim 7. "