JP5379355B2 - Water-based coating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous coating material forming a film having both of blocking resistance, freezing damage resistance, smoothness, water resistance and weatherability, and to provide a method for producing the aqueous coating material. <P>SOLUTION: The aqueous coating material contains emulsion particles with a multi-layered structure provided with a polymer (C) of an ethylenic unsaturated monomer (c) on the outside of a layer containing a polyorganosiloxane polymer (A) and a polymer (B) which is a polymer of an ethylenic unsaturated monomer (b), wherein the ethylenic unsaturated monomer (b) contains 75-100 mass.% of an ethylenic unsaturated monomer (d) having 20-30 (J/cm<SP>3</SP>)<SP>1/2</SP>of solubility parameter (SP value), and the mass ratio of the methylmethacrylate contained as the ethylenic unsaturated monomer (d) in the ethylenic unsaturated monomer (b) to the sum of the ethylenic unsaturated monomer (b) and the ethylenic unsaturated monomer (c) is at least 30 mass.%. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an aqueous coating material that forms a coating film excellent in blocking resistance, frost damage resistance, smoothness, water resistance and weather resistance, and a method for producing the aqueous coating material.

  Conventionally, in the field of paints used for buildings and civil engineering structures, solvent-based paints using volatile organic compounds (hereinafter referred to as VOCs) as solvents have been used. However, considering the health and environmental protection of painters and residents in the vicinity, conversion from a solvent-based paint using VOC as a solvent to an aqueous paint (water-based coating material) using water as a dispersion medium is being attempted.

  However, the emulsion resin used in the water-based emulsion paint, which is a typical water-based paint, has an inherent minimum film-forming temperature (hereinafter referred to as MFT), and at a temperature below the MFT in order to form a coating film. When forming a film, it was necessary to add VOC as a film forming aid.

  Moreover, in order to prevent the blocking which is easy to generate | occur | produce when a coating plate is accumulated, it is necessary to use high-hardness resin as a binder. However, since the coating film of the coating material using a high-hardness resin has low frost resistance and high MFT, it is necessary to add a film-forming aid in a large amount. Therefore, even if it is a water-based emulsion paint, a considerable amount of VOC is contained, and when drying after coating is insufficient, the remaining VOC deteriorates the blocking resistance and water resistance of the coating film. Then, the water-based coating material which has a blocking resistance and a frost damage resistance, and forms the coating film with favorable water resistance and a weather resistance is examined.

  For example, as a resin composition for forming a coating film excellent in blocking resistance, low-temperature stability and low-temperature film-forming property, an ethylenically unsaturated monomer having a core / shell structure and containing a polyethylene glycol chain or a polypropylene glycol chain A resin composition having a shell copolymer as a shell layer is disclosed (Patent Document 1). However, the introduction of a polyethylene glycol chain or polypropylene glycol chain into the resin has a problem that the water resistance and weather resistance of the coating film are lowered, particularly when used for exterior applications.

  In addition, as a resin for forming a coating film excellent in blocking resistance, water resistance, smoothness and weather resistance, a copolymer of an ethylenically unsaturated monomer having a core / shell structure and having a carbonyl group is used as a shell. A resin composition using a layer and containing a compound having two or more hydrazide groups in the molecule is disclosed (Patent Document 2). However, since the hydrophilicity of the coating film is high, there is a problem that the water resistance and weather resistance of the coating film decrease when used for exterior applications.

  Further, as a resin composition for forming a coating film excellent in water resistance, blocking resistance and frost damage resistance, a resin composite having a core / shell structure and using a copolymer of Si-containing monomers is disclosed. (Patent Document 3). However, since the content of the core layer having a high glass transition temperature (hereinafter referred to as Tg) is as low as 10 to 35% by mass, and the Tg of the shell layer is set to 0 ° C. or less for low MFT, the coating film The blocking resistance is not sufficient.

  Patent Document 4 discloses a resin composition having a core / shell structure as a resin composition that forms a coating film excellent in film formability, blocking resistance, coating film hardness, and coating film strength. . However, like the technique of Patent Document 3, the content of the core layer having a high Tg is as low as 10 to 30% by mass, so that the blocking resistance of the coating film is not sufficient.

  Patent Document 5 discloses an acrylic graft silicone resin composite having a core / shell structure as a resin composition that forms a coating film excellent in weather resistance, water resistance, and flexibility. However, since the Tg of the core layer is as low as −60 to 20 ° C., the blocking resistance of the coating film is low.

As described above, conventional water-based paints do not sufficiently satisfy the blocking resistance, frost damage resistance, water resistance and weather resistance of the coating film. Also, the smoothness of the coating film is very important for the paint. Therefore, there is a strong demand for the development of an aqueous coating material that can form a coating film that satisfies these characteristics simultaneously.
JP 2001-164178 A Japanese Patent Laid-Open No. 2002-3778 JP 2003-226793 A JP 2006-143763 A JP 2004-137374 A

  In this invention, the water-based coating material which forms the coating film excellent in blocking resistance, frost damage resistance, smoothness, water resistance, and a weather resistance is provided.

In the present invention, an ethylenically unsaturated monomer (b) is emulsion-polymerized in one or more stages in an aqueous dispersion containing the polyorganosiloxane polymer (A) to form a polymer (B), and then , An aqueous coating material containing emulsion particles obtained by adding an ethylenically unsaturated monomer (c) and emulsion polymerization to form a polymer (C), wherein the ethylenically unsaturated monomer (B) contains 75 to 100% by mass of an ethylenically unsaturated monomer (d) having a solubility parameter (SP value) of 20 to 30 (J / cm ³ ) ^1/2 , The methyl methacrylate contained in the ethylenically unsaturated monomer (b) as the saturated monomer (d) is composed of the ethylenically unsaturated monomer (b) and the ethylenically unsaturated monomer used for emulsion polymerization. relative to the combined weight of the (c), Ri der least 30 mass%, Ethylenic unsaturated monomer (c) is a solubility parameter (SP value) comprises 20 ^{(J /} cm ^{3) 1/2} than the ethylenically unsaturated monomer (e), ethylenically unsaturated monomer mass ratio of ethylenically unsaturated monomer contained in the dimer (c) (e) to provide an aqueous coating material, wherein 65 to 100% by mass Rukoto.

In the present invention, the ethylenically unsaturated monomer (c) is outside the layer containing the polyorganosiloxane polymer (A) and the polymer (B) of the ethylenically unsaturated monomer (b). An aqueous coating material containing emulsion particles having a multilayer structure and comprising a polymer (C), wherein the polymer (B) has a solubility parameter (SP value) of 20 to 30 (J / cm ³ ) ^{1 / 2} to 75% by mass of polymerized units of ethylenically unsaturated monomer (d), and the polymerized unit of methyl methacrylate contained in polymer (B) as said ethylenically unsaturated monomer (d) Is 30 mass with respect to the total mass of the ethylenically unsaturated monomer (b) and the ethylenically unsaturated monomer (c), which are polymer units of the polymer (B) and the polymer (C). der least% is, polymerized units of an ethylenically unsaturated monomer (c) is soluble Pas Comprises polymerized units of meter (SP value) of 20 ^{(J /} cm ^{3) 1/2} than the ethylenically unsaturated monomer (e), is contained in the polymerized units of ethylenically unsaturated monomer (c) that the mass ratio of polymerized units of ethylenically unsaturated monomer (e) is to provide an aqueous coating material, wherein 65 to 100% by mass Rukoto.

  ADVANTAGE OF THE INVENTION According to this invention, the aqueous coating material which forms the coating film excellent in blocking resistance, frost damage resistance, smoothness, water resistance, and a weather resistance can be provided.

Hereinafter, the aqueous coating material of the present invention will be described in detail.
The aqueous coating material of the present invention forms a polymer (B) by emulsion polymerization of the ethylenically unsaturated monomer (b) in one or more stages in an aqueous dispersion containing the polyorganosiloxane polymer (A). Thereafter, the ethylenically unsaturated monomer (c) is added to form a polymer (C) by emulsion polymerization, and the emulsion particles having a multilayer structure obtained thereby are contained.

[Polyorganosiloxane polymer (A)]
Examples of the raw material for the polyorganosiloxane polymer (A) include dimethyldialkoxysilanes such as dimethyldimethoxysilane and dimethyldiethoxysilane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, Examples thereof include dimethylsiloxane cyclic oligomers such as dodecamethylcyclohexasiloxane, tetradecamethylcycloheptasiloxane, and dimethyl cyclic (a mixture of 3 to 7-mer dimethylsiloxane cyclic oligomers), dimethyldichlorosilane, and the like. In consideration of performance and cost such as thermal stability of the resulting polymer (A), it is preferable to use dimethylsiloxane cyclic oligomers.

Further, since the coating film can exhibit high transparency, blocking resistance, frost damage resistance, water resistance, weather resistance, and stain resistance, it is preferably a polyorganosiloxane polymer (A) having a graft crossing point. .
Examples of the silicon-containing graft crossing agent used in the polymerization reaction in this case include compounds containing one or more hydrolyzable silyl groups and one or more vinyl polymerizable functional groups or mercapto groups in the molecule. . The hydrolyzable silyl group is preferably an alkoxysilyl group from the viewpoints of polymerization reactivity, ease of handling, cost, and the like.

Specific examples of the silicon-containing graft crossing agent include vinyl silanes, acryloyloxyalkyl silanes, methacryloyloxyalkyl silanes, mercaptoalkyl silanes, and the like.
Examples of vinyl silanes include vinyl methyl dimethoxy silane, vinyl trimethoxy silane, vinyl triethoxy silane, vinyl methyl dichloro silane, vinyl trichloro silane, and the like.
Examples of acryloyloxyalkylsilanes include γ-acryloyloxyethylmethyldimethoxysilane, γ-acryloyloxyethyltrimethoxysilane, γ-acryloyloxyethyltriethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, and γ-acryloyloxy. Propyltrimethoxysilane, γ-acryloyloxypropyltriethoxysilane, γ-acryloyloxyethylmethyldichlorosilane, γ-acryloyloxyethyltrichlorosilane, γ-acryloyloxypropylmethyldichlorosilane, γ-acryloyloxypropyltrichlorosilane, etc. It is done.
Examples of methacryloyloxyalkylsilanes include γ-methacryloyloxyethylmethyldimethoxysilane, γ-methacryloyloxyethyltrimethoxysilane, γ-methacryloyloxyethyltriethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, and γ-methacryloyloxy. Examples include propyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-methacryloyloxyethylmethyldichlorosilane, γ-methacryloyloxyethyltrichlorosilane, γ-methacryloyloxypropylmethyldichlorosilane, γ-methacryloyloxypropyltrichlorosilane, and the like. It is done.
Examples of mercaptoalkylsilanes include γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and the like.
Of these, acryloyloxyalkylsilanes, methacryloyloxyalkylsilanes, and mercaptoalkylsilanes are more preferable from the viewpoints of vinyl polymerization reactivity, coating stain resistance, weather resistance, and water resistance. These may be used alone or in combination of two or more as required.

  The amount of the silicon-containing graft crossing agent to be added is based on the silicon atom weight in the polyorganosiloxane polymer (A) having a graft crossing point, and the silicon atom weight of the silicon-containing graft crossing agent is in the range of 0.2 to 50 mol%. It is preferable to do this. If it is 0.2 mol% or more, the transparency of the coating film is improved, and if it is 50 mol% or less, the coating film performance is improved. Moreover, it is more preferable to set it as 0.5-15 mol%. If it is 0.5 mol% or more, the transparency of the resulting coating film is further improved, and if it is 15 mol% or less, the latex stability during emulsion polymerization is improved.

The weight average molecular weight of the polyorganosiloxane polymer (A) is preferably 10,000 or more. When the weight average molecular weight is 10,000 or more, the durability of the obtained coating film is increased. The weight average molecular weight is more preferably 50000 or more.
The content of the polyorganosiloxane polymer (A) in the obtained emulsion particles is 0.2 to 150 parts by mass when the total mass of the polymer (B) and the polymer (C) is 100 parts by mass. It is preferable to be within the range. Moreover, it is more preferable that content is 0.5-100 mass parts. If content of a polyorganosiloxane polymer (A) is 0.2 mass part or more, the weather resistance of a coating film, water resistance, frost damage resistance, and smoothness will become high. Moreover, if it is 150 mass parts or less, the fall of the hardness of a coating film, intensity | strength, blocking resistance, and stain resistance can be suppressed.

[Polymer (B)]
In the polymer (B), the ethylenically unsaturated monomer (b) (hereinafter referred to as monomer (b)) is one-stage in the presence of an aqueous dispersion containing the polyorganosiloxane polymer (A). This is obtained by emulsion polymerization. In addition, the monomer (b) of the present invention has an ethylenically unsaturated monomer (monomer (b) having a solubility parameter (SP value) of 20 to 30 (J / cm ³ ) ^1/2. What is contained is particularly ethylenically unsaturated monomer (d), hereinafter referred to as monomer (d)), and is characterized by containing 75 to 100% by mass.
Here, the SP value refers to a value obtained by the Fedors equation (R. F. Fedors, Polym. Eng. Sci., 14, (2), 1974) represented by [Equation 1].

In [Equation 1], δ _j (J / cm ³ ) ^1/2 is the SP value of monomer (j), ΔE (J / mol) is the cohesive energy density of monomer (j), and V (cm ³ / mol) is the molar volume of the monomer (j), Δe _i (J / mol) is the evaporation energy of the atom or atomic group (i), and Δv _i (cm ³ / mol) is the atomic or atomic group ( The molar volume of i) is indicated.

The polymer (B) emulsion-polymerizes the monomer (b) containing 75 to 100% by mass of the monomer (d) having an SP value of 20 to 30 (J / cm ³ ) ^1/2 in one or more stages. It is preferable that the ratio of the monomer (d) in the monomer (b) is 80 to 100% by mass. If monomer (d) is 75 mass% or more, the impregnation property of monomer (b) with respect to polyorganosiloxane polymer (A) will improve, and polyorganosiloxane polymer (A) and polymer (B) ). Therefore, the polymer (B) can be hydrophobized by polyorganosiloxane having high hydrophobicity, and the decrease in water resistance and weather resistance due to the high SP value can be suppressed.
Further, when the monomer (d) is 75% by mass or more, the compatibilization of the polymer (B) and the polymer (C) can be suppressed, and the functional differentiation in the respective polymer layers of the emulsion particles is possible. It becomes. Moreover, when making a polymer (B) high Tg, blocking resistance can be improved, without reducing the freezing damage resistance of a coating film.

Examples of the monomer (d) include methyl (meth) acrylate, ethyl acrylate, propyl acrylate, cyclohexyl acrylate, benzyl acrylate, phenyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl (meth) acrylate, 4 -Ethylenically unsaturated monomers having an SP value of 20 to 25, such as hydroxybutyl (meth) acrylate, methoxyethyl acrylate, methacrylic acid, glycidyl (meth) acrylate, diacetone acrylamide, and styrene. Moreover, the ethylenically unsaturated monomer whose SP value exceeds 25, such as 2-hydroxyethyl acrylate, acrylic acid, itaconic acid, acrylonitrile, etc. is mentioned.
From the viewpoint of water resistance and weather resistance of the coating film, it is preferable to use an ethylenically unsaturated monomer having an SP value of 20 to 25.

  Moreover, the monomer (d) contained in the monomer (b) of this invention combined the monomer (b) and the monomer (c) from the surface of the blocking resistance of a coating film. Based on the total mass of monomers (hereinafter simply referred to as total monomer amount), 30% by mass or more is methyl methacrylate. Moreover, it is preferable that 33 mass% or more is methyl methacrylate. Moreover, it is preferable to use methyl methacrylate at 65 mass% or less from the surface of the frost damage resistance of the coating film.

The Tg of the polymer (B) is preferably 50 to 150 ° C, and more preferably 70 to 110 ° C. If Tg is 50 ° C. or higher, the blocking resistance of the coating film is improved, and if it is 150 ° C. or lower, the frost damage resistance of the coating film is improved.
In order to set the Tg of the polymer (B) to 50 to 150 ° C., the monomer (b) includes, in addition to methyl methacrylate, isobornyl (meth) acrylate, t-butyl methacrylate, cyclohexyl methacrylate, (meth) acrylic acid. An ethylenically unsaturated monomer such as can be used. However, when using an ethylenically unsaturated monomer having an SP value of 20 (J / cm ³ ) ^1/2 or less, such as isobornyl (meth) acrylate, t-butyl methacrylate, cyclohexyl methacrylate, etc., the polymer (B ) And the polymer (C) are preferably suppressed in use from the viewpoint of reducing the effect of suppressing the compatibilization of the polymer (C) and from the viewpoint of frost damage resistance of the coating film. In addition, among ethylenically unsaturated monomers (d), when a highly hydrophilic ethylenically unsaturated monomer such as (meth) acrylic acid is used, the stability in the polymerization process and the coating film From the viewpoint of water resistance and weather resistance, it is preferable to limit the amount used.
Tg is a value obtained by the Fox equation shown in Equation (1).
1 / (273 + Tg) = Σ (W _i / (273 + Tg _i )) (1)
Here, _{W i} is the mass fraction of the monomer i, Tg _i denotes the Tg (° C.) of a homopolymer of the monomer i.

  The content of the polymer (B) having a Tg of 50 to 150 ° C. in the emulsion particles is preferably 30 to 70% by mass with respect to the total monomer amount, and is 35 to 65% by mass. Is more preferable. If content is 30 mass% or more, the blocking resistance of a coating film will become high. Moreover, if content rate is 70 mass% or less, the frost damage resistance of a coating film will become high.

  Further, in the aqueous coating material of the present invention, as shown below, hydroxyalkyl (meth) acrylate, self-crosslinkable functional group-containing ethylenically unsaturated monomer, 2 polymerizable unsaturated double bonds in the molecule. By containing an ethylenically unsaturated monomer having at least one in the monomer (b), more advanced coating properties and coating properties can be expressed. These monomers can use 2 or more types as needed.

  By incorporating hydroxyl (meth) acrylate in the monomer (b), blending stability when producing an aqueous coating material, stain resistance of the coating film, weather resistance, water resistance, and adhesion to various substrates Can be improved. The mass proportion of the hydroxyalkyl (meth) acrylate in the monomer (b) is preferably from 0.1 to 15 mass%, more preferably from 0.5 to 12 mass%. An effect is acquired if the mass ratio in a monomer (b) is 0.1 mass% or more, and if it is 15 mass% or less, the fall of the water resistance of a coating film and a weather resistance can be suppressed.

By containing a self-crosslinkable functional group-containing ethylenically unsaturated monomer in the monomer (b), the coating film has blocking resistance, stain resistance, weather resistance, water resistance, and adhesion to various substrates. Can be improved. The content of the self-crosslinkable functional group-containing ethylenically unsaturated monomer is preferably 0.1 to 15% by mass and more preferably 0.5 to 12% by mass in the monomer (b). An effect is acquired if content is 0.1 mass% or more, and if it is 15 mass% or less, the fall of the water resistance of a coating film and a weather resistance can be suppressed.
Self-crosslinkable functional group-containing ethylenically unsaturated monomer means that the self-crosslinkable functional group remaining in the obtained emulsion particles is chemically stable while the emulsion particles are stored as a dispersion at room temperature. A monomer in which chemical bonds are formed between the side chains by reacting with the functional groups of the side chains by drying, heating, or other external factors during coating.

  Examples of the self-crosslinkable functional group-containing ethylenically unsaturated monomer include oxirane group-containing ethylenically unsaturated monomers such as glycidyl (meth) acrylate, N-methylol (meth) acrylamide, N-butoxymethyl (meta ) An alkylol or alkoxyalkyl compound of an ethylenically unsaturated amide such as acrylamide or N-methoxymethyl (meth) acrylamide. Two or more of these may be selected and used as necessary.

In addition, the monomer (b) contains an ethylenically unsaturated monomer having two or more polymerizable unsaturated double bonds in the molecule, whereby the coating film has blocking resistance, water resistance and weather resistance. Can be improved. The content of the ethylenically unsaturated monomer is preferably 0.05 to 10% by mass and more preferably 0.1 to 8% by mass in the monomer (b). If content is 0.05 mass% or more, the blocking resistance of a coating film, water resistance, and a weather resistance will improve, and if it is 10 mass% or less, the fall of the frost damage resistance of a coating film can be suppressed.
Examples of the ethylenically unsaturated monomer having two or more polymerizable unsaturated double bonds in the molecule include divinylbenzene, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butylene glycol di ( Examples include meth) acrylate, trimethylolpropane tri (meth) acrylate, and allyl (meth) acrylate. Two or more of these may be selected and used as necessary.

The polymer (B) can be produced by carrying out one or more stages of emulsion polymerization, and in the case of two or more stages, it can be produced by a multistage polymerization method. In the case of multistage polymerization, as long as the composition and amount of the predetermined monomer (b) are satisfied, the monomer composition used for the polymerization in each stage may be different as necessary.
For the emulsion polymerization, for example, a known method in which the monomer (b) is supplied into the polymerization system in the presence of a surfactant and polymerized with a radical polymerization initiator can be used.

As the radical polymerization initiator, known ones used for radical polymerization can be used, and examples thereof include persulfates, oil-soluble azo compounds, water-soluble azo compounds, and organic peroxides.
Examples of persulfates include potassium persulfate, sodium persulfate, and ammonium persulfate.
Examples of the oil-soluble azo compounds include azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2, Examples thereof include 2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) and 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile.
Examples of the water-soluble azo compounds include 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, 2,2′-azobis { 2-methyl-N- [2- (1-hydroxyethyl)] propionamide}, 2,2′-azobis {2-methyl-N- [2- (1-hydroxybutyl)] propionamide}, 2,2 '-Azobis [2- (5-methyl-2-imidazolin-2-yl) propane] and salts thereof, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] and salts thereof, 2 , 2′-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] and its salts, 2,2′-azobis {2- [1- (2-hydroxyethyl) -2 -Imidazolin-2-yl Propane} and its salts, 2,2′-azobis (2-methylpropionamidine) and its salts, 2,2′-azobis (2-methylpropyneamidine) and its salts, 2,2′-azobis [N -(2-carboxyethyl) -2-methylpropionamidine] and its salts.
Examples of organic peroxides include benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, t-butyl peroxy-2-ethylhexanoate, and t-butyl peroxyisobutyrate. It is done.
These can be used alone or as a mixture of two or more. When acceleration of the polymerization rate and polymerization at a low temperature of 70 ° C. or lower are desired, for example, a reducing agent such as sodium bisulfite, ferrous sulfate, ascorbate or the like may be used in combination with the radical polymerization catalyst. .

The addition amount of the radical polymerization initiator is usually 0.01 to 10% by mass in the monomer (b), but is 0.05 to 5% by mass from the viewpoint of polymerization progress and reaction control. Is preferred.
In the case of adjusting the molecular weight of the polymer (B), n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, n-tetradecyl mercaptan, n-hexyl mercaptan, etc. are used as molecular weight adjusting agents when polymerizing. Mercaptans, halogen compounds such as carbon tetrachloride and ethylene bromide, and known chain transfer agents such as α-methylstyrene dimer can be used. In order to suppress a decrease in weather resistance, the amount of the chain transfer agent used is preferably 1% by mass or less based on the monomer (b).

  Moreover, it is preferable that 0.1-10 mass parts of surfactant is contained in a monomer (b) with respect to 100 mass parts of monomers (b), and 0.5-8 mass parts is contained. Is more preferable. By containing 0.1 part by mass or more of the surfactant in the monomer (b), the polymerization stability and storage stability of the resulting emulsion particles are improved. Further, when the surfactant to be contained is 10 parts by mass or less, the stability at the time of forming a paint, the stability over time of the paint, and the like can be maintained without impairing the water resistance of the coating film.

  Examples of the surfactant include various anionic, cationic or nonionic surfactants and polymer emulsifiers. A reactive surfactant having an ethylenically unsaturated bond in the surfactant component can also be used. Especially, it is preferable to use a reactive surfactant from the viewpoint of the weather resistance and water resistance of the coating film. At this time, in order to improve the weather resistance and water resistance of the coating film, it is preferable that 50% by mass or more of the surfactant component is a reactive surfactant.

In addition, the “more” and “mud crack” of the coating does not occur during the drying after coating, and the foaming property in the dispersion of the emulsion particles obtained from the viewpoint of obtaining a coating with high smoothness. From the viewpoint of lowering, it is preferable to use a phosphate ester type reactive surfactant in combination. At this time, the content of the phosphate ester type reactive surfactant is preferably 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass, with the total monomer amount being 100 parts by mass. Is more preferable. The effect is obtained when the content is 0.05 parts by mass or more, and when the content is 5 parts by mass or less, the water resistance and weather resistance of the coating film can be prevented from lowering.
As the phosphate type reactive surfactant, commercially available products can be used. For example, FP-80, FP-100, FP-120, FP-160, FP, which are Surfmer series manufactured by Toho Chemical Industry Co., Ltd. -200, FP-125, Asahi Denka Kogyo Co., Ltd. Adekaria soap series PP-70, PPE-710 and the like. Two or more of these may be selected and used as necessary.

[Polymer (C)]
The polymer (C) is an ethylenically unsaturated monomer (c) (hereinafter referred to as monomer (c)) after emulsion polymerization of monomer (b) to form polymer (B). ) And emulsion polymerization.
The monomer (c) is not particularly limited as long as it is a radically polymerizable ethylenically unsaturated monomer, but an ethylenically unsaturated monomer having an SP value of less than 20 (J / cm ³ ) ^1/2 is used. It is preferable to contain (SP value is less than 20 (J / cm ³ ) ^1/2 , and what is contained in the monomer (c) is particularly an ethylenically unsaturated monomer (e), And monomer (e)). The mass ratio of the monomer (e) contained in the monomer (c) is preferably 65 to 100% by mass, and more preferably 70 to 100% by mass. When the proportion of the monomer (e) is 65% by mass or more, the water absorption resistance is improved, so that the water resistance, weather resistance and frost damage resistance of the coating film are improved, and the smoothness is also increased. In order to increase the smoothness of the coating film, it is more preferable to use a monomer (e) having an SP value of 19.5 or less.

  Examples of the monomer (e) include SP such as ethyl methacrylate, i-propyl acrylate, n-butyl acrylate, cyclohexyl methacrylate, 2-methoxyethyl methacrylate, ethoxyethyl acrylate, n-propoxyethyl acrylate, and methoxyethoxyethyl acrylate. 19.5-20 ethylenically unsaturated monomers, n-propyl methacrylate, i-butyl acrylate, n-butyl methacrylate, n-hexyl acrylate, isobornyl acrylate, α-methyl styrene, p-methyl styrene SP values of 2-ethoxyethyl methacrylate, i-propoxyethyl acrylate, n-butoxyethyl acrylate, ethoxyethoxyethyl acrylate, dimethylaminoethyl methacrylate, etc. 9.0 to 19.5 ethylenically unsaturated monomers, i-propyl methacrylate, t-butyl (meth) acrylate, i-butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl (meth) acrylate, lauryl (meta And ethylenically unsaturated monomers having an SP value of 19.0 or less, such as acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, isobornyl methacrylate, t-butoxyethyl acrylate, diethylaminoethyl methacrylate, and the like.

The Tg of the polymer (C) is preferably -50 to 50 ° C, and more preferably -30 to 30 ° C. If Tg of a polymer (C) is -50 degreeC or more, the blocking resistance and stain | pollution resistance of a coating film will be obtained. In addition, if the Tg of the polymer (C) is 50 ° C. or less, the film-forming property is high, and even if the drying after coating is insufficient, the coating film has the blocking resistance, water resistance and freezing damage due to the remaining VOC. The adverse effect on sex is reduced.
Moreover, it is preferable that content of the polymer (C) whose Tg is -50-50 degreeC in the obtained emulsion particle | grains is 30-70 mass% on the basis of the total amount of monomers, 35-65. More preferably, it is mass%. If content of a polymer (C) is 30 mass% or more, the frost damage resistance, smoothness, water resistance, and weather resistance of a coating film will become high. Moreover, if content of a polymer (C) is 70 mass% or less, the blocking resistance of a coating film will improve.

  Further, in order to develop the high-level coating properties and coating properties as described below, the monomer (c) includes t-butyl methacrylate and / or cyclohexyl methacrylate, hydrolyzable silyl group-containing ethylenic monomer. Unsaturated monomer, ethylenically unsaturated carboxylic acid, hydroxyalkyl (meth) acrylate, polyoxyalkylene group-containing (meth) acrylate, self-crosslinkable functional group-containing ethylenically unsaturated monomer, UV resistant ethylenically unsaturated A monomer, a metal-containing ethylenically unsaturated monomer, a carbonyl group and / or an aldehyde group-containing ethylenically unsaturated monomer can be contained. These may use 2 or more types together as needed.

  If the monomer (c) contains t-butyl methacrylate and / or cyclohexyl methacrylate, the weather resistance and water resistance of the coating film are improved. The content of t-butyl methacrylate and / or cyclohexyl methacrylate in the monomer (c) is preferably 5 to 70% by mass, and more preferably 10 to 60% by mass. When the content is 5% by mass or more, the weather resistance and water resistance of the coating film can be improved.

  If the monomer (c) contains a hydrolyzable silyl group-containing ethylenically unsaturated monomer, the weather resistance and water resistance of the coating film are improved. The content of the hydrolyzable silyl group-containing ethylenically unsaturated monomer in the monomer (c) is preferably 0.05 to 15% by mass, and preferably 0.1 to 12% by mass. More preferred. When the content is 0.05% by mass or more, the weather resistance and water resistance of the coating film can be improved.

Examples of the hydrolyzable silyl group-containing ethylenically unsaturated monomer include vinylsilanes such as vinylmethyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldichlorosilane, and vinyltrichlorosilane, and γ- ( Meth) acryloyloxyethylmethyldimethoxysilane, γ- (meth) acryloyloxyethyltrimethoxysilane, γ- (meth) acryloyloxyethyltriethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ- (meth) Acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxyethylmethyldichlorosilane, γ- (meth) acryloyloxyethyltrichlorosilane (Meth) acryloyloxyalkylsilanes such as lanthanum, γ- (meth) acryloyloxypropylmethyldichlorosilane, γ- (meth) acryloyloxypropyltrichlorosilane, and the like.
Of these, (meth) acryloyloxyalkylsilanes are preferred from the viewpoints of vinyl polymerization reactivity and stain resistance, weather resistance and water resistance of the coating film, and γ-methacryloyloxyethylmethyldimethoxysilane, γ- Methacryloyloxyethyltrimethoxysilane, γ-methacryloyloxyethyltriethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-methacryloyloxyethylmethyldi More preferable are chlorosilane, γ-methacryloyloxyethyltrichlorosilane, γ-methacryloyloxypropylmethyldichlorosilane, and γ-methacryloyloxypropyltrichlorosilane. Arbitrariness. Moreover, these can also select and use 2 or more types as needed.

  If the monomer (c) contains an ethylenically unsaturated carboxylic acid, the storage stability of the dispersion of emulsion particles and the blending stability when a pigment or additive is added to the dispersion of emulsion particles to form a paint Improves. The content of ethylenic saturated carboxylic acid in the monomer (c) is preferably 0.1 to 10% by mass, and more preferably 0.2 to 8% by mass. If content is 0.1 mass% or more, the effect by adding ethylenically unsaturated carboxylic acid will be acquired, and the weather resistance of a coating film and the fall of water resistance can be suppressed by setting it as 10 mass% or less.

  Examples of the ethylenically unsaturated carboxylic acid include (meth) acrylic acid, itaconic acid, citraconic acid, maleic acid, monomethyl maleate, monobutyl maleate, monomethyl itaconate, monobutyl itaconate, vinylbenzoic acid, monohydroxy oxalate Ethyl (meth) acrylate, tetrahydrophthalic acid monohydroxyethyl (meth) acrylate, tetrahydrophthalic acid monohydroxypropyl (meth) acrylate, 5-methyl-1,2-cyclohexanedicarboxylic acid monohydroxyethyl (meth) acrylate, phthalic acid mono Hydroxyethyl (meth) acrylate, monohydroxypropyl (meth) acrylate phthalate, monohydroxyethyl (meth) acrylate maleate, hydroxypropyl (meth) acrylate maleate Over DOO, tetrahydrophthalic acid mono-hydroxybutyl (meth) acrylate. Two or more of these may be selected and used as necessary.

  If the monomer (c) contains a hydroxyalkyl (meth) acrylate, the blending stability of the emulsion particle dispersion, the stain resistance of the coating, the weather resistance, the water resistance, and the various bases of the coating Adhesion with respect to is improved. The content of the hydroxyalkyl (meth) acrylate in the monomer (c) is preferably from 0.1 to 15% by mass, and more preferably from 0.5 to 12% by mass. If the content is 0.1% by mass or more, the effect is sufficiently obtained, and by setting the content to 15% by mass or less, it is possible to suppress deterioration of water resistance and weather resistance of the coating film.

  If a polyoxyalkylene group-containing (meth) acrylate is contained in the monomer (c), the blending stability of the emulsion particle dispersion, the stain resistance of the coating, the weather resistance, the water resistance, and the coating Adhesion to various bases is improved. The content of the polyoxyalkylene group-containing (meth) acrylate in the monomer (C) is preferably 0.1 to 15% by mass, and more preferably 0.5 to 12% by mass. When the content is 0.1% by mass or more, the effect is sufficiently obtained, and when the content is 15% by mass or less, deterioration of water resistance and weather resistance of the coating film can be suppressed.

  Examples of polyoxyalkylene group-containing (meth) acrylates include hydroxypolyethylene oxide mono (meth) acrylate, hydroxypolypropyleneoxide mono (meth) acrylate, hydroxy (polyethyleneoxide-polypropyleneoxide) mono (meth) acrylate, and hydroxypoly (ethyleneoxide) / Propylene oxide) mono (meth) acrylate, hydroxy (polyethylene oxide-polytetramethylene oxide) mono (meth) acrylate, hydroxy poly (ethylene oxide / tetramethylene oxide) mono (meth) acrylate, hydroxy (polypropylene oxide-polytetramethylene oxide) ) Mono (meth) acrylate, hydroxypoly (propylene oxide / tetramethylene oxide) Terminal hydroxy type polyalkylene oxide group-containing ethylenically unsaturated monomers such as (meth) acrylate, methoxypolyethylene oxide mono (meth) acrylate, lauroxypolyethylene oxide mono (meth) acrylate, stearoxypolyethylene oxide mono (meth) Acrylate, allyloxypolyethylene oxide mono (meth) acrylate, nonylphenoxypolyethyleneoxide mono (meth) acrylate, nonylphenoxypolypropyleneoxide mono (meth) acrylate, octoxy (polyethyleneoxide-polypropyleneoxide) mono (meth) acrylate, nonylphenoxy (poly (Ethylene oxide-propylene oxide) mono (meth) acrylate and other alkyl group end-capped polyalkylene oxide groups Ethylenic unsaturated monomers. Two or more of these may be selected and used as necessary.

  If the monomer (c) contains a self-crosslinkable functional group-containing ethylenically unsaturated monomer, the coating film has stain resistance, weather resistance, water resistance, and adhesion of the coating film to various substrates. improves. The content of the self-crosslinkable functional group-containing ethylenically unsaturated monomer in the monomer (c) is preferably 0.1 to 15% by mass, and more preferably 0.5 to 12% by mass. . When the content is 0.1% by mass or more, the effect is sufficiently obtained, and when the content is 15% by mass or less, deterioration of water resistance and weather resistance of the coating film can be suppressed. As the self-crosslinkable functional group-containing ethylenically unsaturated monomer, those listed in the case of the monomer (b) can be used, and two or more of them may be selected and used as necessary. .

  If an ultraviolet-resistant ethylenically unsaturated monomer is contained in the monomer (c), the weather resistance of the coating film is improved. The content of the ultraviolet-resistant ethylenically unsaturated monomer in the monomer (c) is preferably 0.1 to 20% by mass, and more preferably 0.2 to 15% by mass. When the content is 0.1% by mass or more, the effect is sufficiently obtained, and when the content is 20% by mass or less, a decrease in polymerization stability can be suppressed.

Examples of the ultraviolet-resistant ethylenically unsaturated monomer include (meth) acrylate having a light stabilizing action and (meth) acrylate having an ultraviolet-absorbing component.
Examples of the (meth) acrylate having a light stabilizing action include 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-2,2,6,6. -Tetramethylpiperidine, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4 -Cyano-4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine and the like.
Examples of the (meth) acrylate having an ultraviolet absorbing component include 2- [2-hydroxy-5- (meth) acryloyloxyethylphenyl] -2H-benzotriazole, 2- [2-hydroxy-3-t-butyl. -5- (meth) acryloyloxyethylphenyl] -2H-benzotriazole, 2- [2-hydroxy-3-t-amyl-5- (meth) acryloyloxyethylphenyl] -2H-benzotriazole, and the like.
Two or more kinds of these ultraviolet-resistant ethylenically unsaturated monomers may be selected and used as necessary.

  When high stain resistance of the coating film is required or when the stain resistance of the coating film decreases due to bleed out of the plasticizer, the metal-containing ethylenically unsaturated monomer in the monomer (c) If a specific crosslinking system is contained, the stain resistance of the coating film is improved. Examples of the metal-containing ethylenically unsaturated monomer include monomers represented by the following formula.

In the formula, R ¹ represents a hydrogen atom or a methyl group, M represents a divalent metal ion such as Mg, Ca, Fe, Cu, Zn, or Zr, and R ² represents an organic acid residue.
When the organic acid residue is a (meth) acrylic acid residue, it is a metal-containing ethylenically unsaturated monomer having two unsaturated groups, such as magnesium di (meth) acrylate, methacrylic acid methacrylic. Magnesium oxide, calcium di (meth) acrylate, calcium acrylate methacrylate, iron di (meth) acrylate, iron acrylate methacrylate, copper di (meth) acrylate, copper acrylate methacrylate, di (meth) acrylic Zinc acid zinc, zinc methacrylate acrylic acid, zirconium di (meth) acrylate, zirconium methacrylate methacrylate.

When R ^{2 of the} metal-containing ethylenically unsaturated monomer is an organic acid residue other than a (meth) acrylic acid residue, preferred organic acid residues include, for example, monochloroacetic acid, monofluoroacetic acid, propionic acid, octyl Acid, versatic acid, isostearic acid, palmitic acid, crestic acid, α-naphthoic acid, β-naphthoic acid, benzoic acid, 2,4,5-trichlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, quinolinecarboxylic acid, nitro Examples thereof include those derived from monovalent organic acids such as benzoic acid, nitronaphthalene carboxylic acid, and puruvic acid.
Specific examples of the metal-containing ethylenically unsaturated monomer include monochloro magnesium acetate (meth) acrylate, monochloro calcium acetate (meth) acrylate, monochloro iron acetate (meth) acrylate, monochloro copper acetate (meth) acrylate, monochloroacetic acid Zinc (meth) acrylate, monochloro zirconium acetate (meth) acrylate, magnesium monofluoroacetate (meth) acrylate, calcium monofluoroacetate (meth) acrylate, iron monofluoroacetate (meth) acrylate, copper monofluoroacetate (meth) acrylate, Zinc monofluoroacetate (meth) acrylate, zirconium monofluoroacetate (meth) acrylate, magnesium propionate (meth) acrylate, calcium propionate (meth) acrylate , Iron propionate (meth) acrylate, copper propionate (meth) acrylate, zinc propionate (meth) acrylate, zirconium propionate (meth) acrylate, magnesium octylate (meth) acrylate, calcium octylate (meth) acrylate, octyl Iron (meth) acrylate, copper octylate (meth) acrylate, zinc octylate (meth) acrylate, zirconium octylate (meth) acrylate, magnesium versatate (meth) acrylate, calcium versatate (meth) acrylate, iron versatate (Meth) acrylate, versatic acid copper (meth) acrylate, versatic acid zinc (meth) acrylate, versatic acid zirconium (meth) acrylate, isostearin Magnesium (meth) acrylate, calcium isostearate (meth) acrylate, iron isostearate (meth) acrylate, copper isostearate (meth) acrylate, zinc isostearate (meth) acrylate, zirconium isostearate (meth) acrylate, magnesium palmitate ( (Meth) acrylate, calcium palmitate (meth) acrylate, iron palmitate (meth) acrylate, copper palmitate (meth) acrylate, zinc palmitate (meth) acrylate, zirconium palmitate (meth) acrylate, magnesium cresotate (meth) Acrylate, calcium cresotate (meth) acrylate, iron cresotate (meth) acrylate, copper cresotate (meth) acrylate, Zinc sootate (meth) acrylate, zirconium cresoate (meth) acrylate, α-magnesium magnesium (meth) acrylate, α-calcium naphthoate (meth) acrylate, α-naphthoic acid iron (meth) acrylate, α-naphthoic acid Copper (meth) acrylate, alpha-naphthoic acid zinc (meth) acrylate, alpha-naphthoic acid zirconium (meth) acrylate, beta-magnesium naphthoic acid (meth) acrylate, beta-naphthoic acid calcium (meth) acrylate, beta-naphthoic acid Iron (meth) acrylate, β-naphthoic acid copper (meth) acrylate, β-naphthoic acid zinc (meth) acrylate, β-naphthoic acid zirconium (meth) acrylate, magnesium benzoate (meth) acrylate, calcium benzoate (meth) Accel Relay , Iron benzoate (meth) acrylate, copper benzoate (meth) acrylate, zinc benzoate (meth) acrylate, zirconium benzoate (meth) acrylate, 2,4,5-trichlorophenoxymagnesium acetate (meth) acrylate, 2, 4,5-trichlorophenoxyacetate calcium (meth) acrylate, 2,4,5-trichlorophenoxyacetate iron (meth) acrylate, 2,4,5-trichlorophenoxyacetate copper (meth) acrylate, 2,4,5-trichloro Zinc phenoxyacetate (meth) acrylate, 2,4,5-trichlorophenoxyacetate zirconium (meth) acrylate, 2,4-dichlorophenoxyacetate magnesium (meth) acrylate, 2,4-dichlorophenoxyacetate calcium (meth) acrylate, 2 , 4 Dichlorophenoxyacetic acid iron (meth) acrylate, 2,4-dichlorophenoxyacetic acid copper (meth) acrylate, 2,4-dichlorophenoxyacetic acid zinc (meth) acrylate, 2,4-dichlorophenoxyacetic acid zirconium (meth) acrylate, quinolinecarbon Magnesium acid (meth) acrylate, calcium quinolinecarboxylate (meth) acrylate, quinolinecarboxylic acid iron (meth) acrylate, quinolinecarboxylate copper (meth) acrylate, quinolinecarboxylate zinc (meth) acrylate, quinolinecarboxylate zirconium (meth) Acrylate, magnesium nitrobenzoate (meth) acrylate, calcium nitrobenzoate (meth) acrylate, iron nitrobenzoate (meth) acrylate, copper nitrobenzoate (meth) acrylate , Zinc nitrobenzoate (meth) acrylate, zirconium nitrobenzoate (meth) acrylate, magnesium nitronaphthalenecarboxylate (meth) acrylate, calcium nitronaphthalenecarboxylate (meth) acrylate, iron (meth) acrylate nitronaphthalenecarboxylate , Copper nitrobenzoate (meth) acrylate, Zinc nitrobenzoate (meth) acrylate, Zirconium nitrobenzoate (meth) acrylate, Magnesium rubate (meth) acrylate, Calcium puruvate (meth) acrylate, Iron puruvate (meth) Examples thereof include copper (meth) acrylate acrylate, zinc (meth) acrylate, and zirconium (meth) acrylate.
Two or more of these can be selected and used as required, but among them, it is preferable to use a zinc-containing ethylenically unsaturated monomer.

  The content of the metal-containing ethylenically unsaturated monomer in the monomer (c) is preferably 0.1 to 10% by mass, and more preferably 0.5 to 8% by mass. When the content is 0.1% by mass or more, the stain resistance of the coating film is improved.

  When the monomer (c) contains a carbonyl group and / or aldehyde group-containing ethylenically unsaturated monomer to prepare an aqueous coating material, at least two molecules in the molecule are contained in the dispersion of emulsion particles. If an organic hydrazine compound having a hydrazino group (hereinafter referred to as a hydrazine compound) is blended, the coating film has blocking resistance, frost resistance, water resistance, weather resistance, stain resistance, solvent resistance, and various types of coating films. Adhesion to the base is improved. This effect is attributed to the fact that a crosslinking reaction proceeds between the carbonyl group in the emulsion particles and the hydrazino group of the blended hydrazine compound during drying after coating.

  Examples of the carbonyl group and / or aldehyde group-containing ethylenically unsaturated monomer include acrolein, diacetone acrylamide, formyl styrene, vinyl alkyl ketone, and the like. Among them, vinyl methyl ketone having 4 to 7 carbon atoms, vinyl ethyl ketone, vinyl isobutyl ketone, (meth) acryloxyalkylpropanal, (meth) acrylamide, pivalin aldehyde, diacetone (meth) acrylate, acetonyl acrylate Acetoacetoxyethyl (meth) acrylate and the like are preferable, and acrolein, diacetone acrylamide, and vinyl methyl ketone are more preferable. Two or more of these can be selected and used as necessary.

  The content of the carbonyl group and / or aldehyde group-containing ethylenically unsaturated monomer in the monomer (c) is preferably 0.2 to 10% by mass, and 0.5 to 8% by mass. Is more preferable. If the content is 0.2% by mass or more, blocking resistance, frost damage resistance, water resistance, weather resistance, stain resistance, solvent resistance and adhesion to various bases of the coating film are improved, and 10% by mass. If it is below, the fall of polymerization stability and the water resistance of a coating film can be suppressed.

Examples of the hydrazine compound include ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene-1,4-dihydrazine, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, Adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, isophthalic acid dihydrazide, itaconic acid dihydrazide, etc. 5-isopropylhydantoin, 1,3-bis (hydrazinocarboethyl) -5- (2-methylmercaptoethyl) hydantoin, 1-hydrazinocarboethyl-3-hydrazinocarboisopropyl-5- (2-methylmercaptoeth ) Include compounds having the hydantoin skeleton such as hydantoin. Two or more of these may be selected and used as necessary.
In order to improve the stain resistance of the coating film, a hydrazine compound having a hydrantin skeleton is preferable, and 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin is more preferable.

  The ratio of the carbonyl group and / or aldehyde group-containing ethylenically unsaturated monomer to the hydrazine compound is the number of moles of carbonyl group and / or aldehyde group in the emulsion particles (P). When the number of moles of hydrazino group of the hydrazine compound to be used is (Q), the ratio (P) / (Q) is preferably 0.1 to 10, and more preferably 0.8 to 2. If (P) / (Q) is 0.1 or more, a decrease in water resistance of the coating film due to the unreacted hydrazine compound can be suppressed, and if (P) / (Q) is 10 or less, the emulsion particles The degree of cross-linking increases, and the coating film's blocking resistance, frost damage resistance, water resistance, weather resistance, stain resistance, solvent resistance, and adhesion of the coating film to various substrates are improved.

  In the production of the polymer (C), a polymerization initiator, a surfactant and a chain transfer agent can be used as in the production of the polymer (B). The use amount of the surfactant is 0 when the total amount of the use amount in the polymerization reaction for forming the polymer (B) is 100 parts by mass of the total mass of the monomers that are the raw materials of the emulsion particles. It is preferable to be 1 to 10 parts by mass.

  The aqueous coating material of the present invention forms a polymer (B) by emulsion polymerization of the ethylenically unsaturated monomer (b) in one or more stages in an aqueous dispersion containing the polyorganosiloxane polymer (A). And a step of adding an ethylenically unsaturated monomer (c) followed by emulsion polymerization to form a polymer (C). Here, the multistage emulsion polymerization of the ethylenically unsaturated monomer is repeated in two or more stages by a known emulsion polymerization method in an aqueous medium. It is common.

After the emulsion polymerization, the resulting dispersion of emulsion particles can be improved in stability by adding a basic compound to a pH in the range of 6.5 to 10.0. Especially, if the pH is 7.0 to 10.0, more excellent freeze-thaw stability can be imparted.
Examples of the basic compound include ammonia, triethylamine, propylamine, dibutylamine, amylamine, 1-aminooctane, 2-dimethylaminoethanol, ethylaminoethanol, 2-diethylaminoethanol, 1-amino-2-propanol, 2- Amino-1-propanol, 2-amino-2-methyl-1-propanol, 3-amino-1-propanol, 1-dimethylamino-2-propanol, 3-dimethylamino-1-propanol, 2-propylaminoethanol, Examples include ethoxypropylamine, aminobenzyl alcohol, morpholine, sodium hydroxide, potassium hydroxide and the like.
Among these, in the case of interior use where it is desired not to contain VOC, it is preferable to use an inorganic base compound. Further, when a slight odor is a problem, it is preferable to use a non-volatile basic compound such as sodium hydroxide or potassium hydroxide.

[Emulsion particles]
The particle diameter of the emulsion particles is preferably 50 to 300 nm from the balance of particle stability and coating film performance. If polymerization conditions are used to form emulsion particles having a particle diameter of 50 nm or more, aggregates are unlikely to form during polymerization, and the amount of surfactant used may be small, so that the water resistance of the coating film can be maintained. Moreover, if it is an emulsion particle | grain of 300 nm or less, a film forming defect will not produce easily.

  The MFT of the emulsion particles is preferably 60 ° C. or lower, and more preferably 50 ° C. or lower. If the MFT is 60 ° C. or less, it is not necessary to add a large amount of VOC (film forming aid), and even if the drying after coating is insufficient, the coating film has a blocking resistance and water resistance due to the remaining VOC. There is no decrease, and the frost damage resistance of the coating film can be maintained.

  The relationship between the Tg of the emulsion polymer (C) and the MFT of the emulsion particles is preferably (MFT of the emulsion particles) ≦ (Tg of the emulsion polymer (C) + 30 ° C.), and (MFT of the emulsion particles) ≦ (Tg of emulsion polymer (C) + 20 ° C.) is more preferable. If the above conditions are satisfied, it is not necessary to add a large amount of film forming aid, and even if the drying after coating is insufficient, there is no decrease in blocking resistance or water resistance of the coating film due to the remaining VOC. The frost damage resistance of the coating film can also be maintained.

  Moreover, it is preferable to make MFT 10 degrees C or less by adding 0-20 mass parts of organic volatile compounds, such as a film forming adjuvant and a plasticizer, with respect to 100 mass parts of emulsion particles. More preferably, it is 0-10 mass parts. Even if the post-coating drying is insufficient by adding less than 20 parts by weight of VOC such as a film-forming aid and plasticizer, there is no adverse effect on the blocking resistance and water resistance of the coating film due to the remaining VOC. The frost damage resistance of the coating film can also be maintained.

[Water-based coating material]
The aqueous coating material of the present invention forms a solid content with emulsion particles as the main component and the surfactant, additive, etc., and is usually used in a state of 20 to 80% by mass of the solid content.
Aqueous coating materials are various pigments, antifoaming agents, pigment dispersants, leveling agents, anti-sagging agents, matting agents, UV absorbers, antioxidants, heat resistance improvers, slip agents, preservatives, etc. It may contain. Moreover, you may mix and use hardening agents, such as another emulsion resin, water-soluble resin, a viscosity control agent, and melamines.

  Examples of methods for coating the surface of various substrates with the aqueous coating material of the present invention include various methods such as spray coating, roller coating, bar coating, air knife coating, brush coating, dipping, and flow coating. The painting method can be selected. Moreover, the aqueous coating material of this invention can obtain the coating film formed into a film sufficiently by room temperature drying or heat drying of 50-180 degreeC.

  In the aqueous coating material of this invention demonstrated above, it becomes a coating film excellent in weather resistance, water resistance, frost damage resistance, and smoothness by the polyorganosiloxane polymer (A). Moreover, since a polymer (B) is high hardness, it becomes a coating film which has favorable blocking resistance. In addition, the polymer (C) increases the frost damage resistance, smoothness, water resistance and weather resistance of the coating film.

EXAMPLES Hereinafter, an Example and a comparative example are shown and this invention is demonstrated in detail. However, the present invention is not limited by the following description.
In the following description, “parts” and “%” are all based on mass.
[Production Example 1]
An aqueous dispersion of the polyorganosiloxane polymer (A) was prepared by the method shown below.
From 95 parts of cyclic dimethylsiloxane oligomer 3 to 7-mer mixture, 5 parts of γ-methacryloyloxypropyltrimethoxysilane, 250 parts of deionized water, 0.4 part of sodium dodecylbenzenesulfonate and 0.4 part of dodecylbenzenesulfonic acid The resulting composition was premixed with a homomixer and forcibly emulsified with a pressure homogenizer at a pressure of 200 kg / cm ² to obtain a raw material pre-emulsion.
Next, 55 parts of water and 5 parts of dodecylbenzenesulfonic acid were charged into a flask equipped with a stirrer, a reflux condenser, a temperature controller and a dropping pump, and the above raw materials were maintained while maintaining the internal temperature of the flask at 85 ° C. with stirring. The pre-emulsion was added dropwise over 4 hours. After completion of the dropwise addition, polymerization was further carried out for 1 hour, followed by cooling and addition of dodecylbenzenesulfonic acid and an equimolar amount of ammonia to prepare an aqueous dispersion (SiEm) of the polyorganosiloxane polymer (A). The solid content was 22.7%.

Hereinafter, aqueous dispersion of polyorganosiloxane polymer (A), emulsion B, emulsion C, hydrazine compound for obtaining dispersions of emulsion particles of Examples 1 to 6, Reference Examples and Comparative Examples 1 to 3 Tables 1 and 2 show the amounts of these. Here, the emulsion B in Table 1 is a mixture of the monomer (b), deionized water, and a surfactant for forming the polymer (B). The emulsion C is a mixture of the monomer (c), deionized water, and a surfactant for forming the polymer (C). In Tables 1 and 2, the monomer (e ′) is an ethylenically unsaturated monomer having an SP value of less than 20 contained in the emulsion B, and the monomer (d ′) is an emulsion. It is an ethylenically unsaturated monomer having an SP value of 20 or more contained in C.
The abbreviations in the table are as follows. The Tg of the monomer homopolymer is shown in parentheses.
MMA: Methyl methacrylate [105 ° C]
2-HEMA: 2-hydroxyethyl methacrylate [55 ° C.]
GMA: Glycidyl methacrylate [46 ° C.]
MAA: Methacrylic acid [185 ° C.]
AA: Acrylic acid [106 ° C]
t-BMA: t-butyl methacrylate [108 ° C.]
CHMA: cyclohexyl methacrylate [83 ° C]
n-BMA: n-butyl methacrylate [20 ° C.]
2-EHA: 2-ethylhexyl acrylate [−55 ° C.]
n-BA: n-butyl acrylate [−45 ° C.]
EDMA: ethylene glycol dimethacrylate [unknown]
DAAm: Diacetone acrylamide [65 ° C]
SZ-6030: γ-methacryloyloxypropyltrimethoxysilane (manufactured by Dow Corning Toray Silicone Co., Ltd.) [Unknown]
KBM-502: γ-methacryloyloxypropyldimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) [Unknown]
ADEKA rear soap SR-1025: Reactive anionic surfactant (trade name, manufactured by Asahi Denka Co., Ltd.)
Surfmer FP-120: Phosphate ester type reactive surfactant (trade name, manufactured by Toho Chemical Industry Co., Ltd.)
ADH: Adipic acid dihydrazide

After emulsion polymerization of the monomer (c) to obtain emulsion particles, an aqueous coating material was obtained as follows.
[Production of water-based coating material (clear paint)]
When the MFT of the emulsion particles exceeded 10 ° C., diethylene glycol monobutyl ether (hereinafter referred to as “BDG”) was added as a film forming aid to make the MFT 10 ° C. or less. Next, 0.5 g of RHEOLATE 350 (manufactured by RHEOX Co., Ltd., thickener) and 0.5 g of Surfynol DF-58 (manufactured by Air Products Co., Ltd., antifoaming agent) are added to 100 g of the dispersion of emulsion particles. In addition, the mixture was sufficiently stirred and deionized water was added to the Ford Cup # 4 for about 30 seconds. Thereafter, filtration was carried out using a 100 mesh nylon bag to obtain an aqueous coating material for evaluation.

[Example 1]
In a flask equipped with a stirrer, a reflux condenser, a temperature controller, a dropping pump, and a nitrogen introduction tube, 57 parts of deionized water, 44 parts of SiEm, and 5 of the emulsion B (raw material for polymer (B)) shown in Table 1 %, And the temperature was raised to 80 ° C. while replacing the inside of the flask with nitrogen. Thereafter, polymerization was performed by adding a polymerization initiator solution in which 0.1 part of ammonium persulfate was dissolved in 1 part of deionized water to form seed particles. After confirming the exothermic peak, when the internal temperature of the flask reached 80 ° C., the remainder of the emulsion B was added dropwise over 1.25 hours while maintaining the temperature, and the internal temperature of the flask was 80 ° C. for 1 hour. Polymerization was performed to form a polymer (B) of emulsion particles. Next, in order to form a polymer (C) of emulsion particles, a polymerization initiator solution in which 0.1 part of ammonium persulfate was dissolved in 3 parts of deionized water in the state where the internal temperature of the flask was 80 ° C. and Table 1 The described emulsion C (raw material for polymer (C)) was added dropwise over 1.25 hours. After completion of the dropwise addition, polymerization was further performed at 80 ° C. for 2 hours. Then, it cooled to room temperature and adjusted pH to 8 with 28% ammonia aqueous solution, and obtained the dispersion liquid of the emulsion particle | grains.
Using this emulsion particle dispersion, 8 parts of a film-forming aid BDG was added to 100 parts of the emulsion particles to prepare an aqueous coating material for evaluation.

[Example 2]
Emulsion B and Emulsion C having the composition shown in Table 1 were used, and the dropping time of the remaining portion of Emulsion B was 1 hour, and the dropping time of Emulsion C was 1.5 hours. Other conditions were the same as in Example 1 to obtain a dispersion of emulsion particles. Moreover, 6 parts of film-forming aid BDG was added to 100 parts of the emulsion particles to prepare an aqueous coating material for evaluation.

[Example 3]
A dispersion liquid of emulsion particles was obtained in the same manner as in Example 1 except that the emulsion B and the emulsion C having the composition shown in Table 1 were used. 7 parts of a film-forming auxiliary BDG was added to 100 parts of the emulsion particles to prepare an aqueous coating material for evaluation.

[ Reference example ]
Using emulsion B and emulsion C having the composition shown in Table 1, and adjusting the pH to 8 with 28% aqueous ammonia solution after polymerization, 1.4 parts of adipic acid dihydrazide was dispersed in 3 parts of deionized water. A dispersion liquid of emulsion particles was obtained in the same manner as in Example 1 except for adding the above. An aqueous coating material for evaluation was prepared by adding 2.5 parts of a film-forming auxiliary BDG to 100 parts of the emulsion particles.

[Example 4 ]
First, 85 parts of deionized water and 4.4 parts of SiEm charged into the flask were used, and emulsion particles B and emulsions C having the composition shown in Table 1 were used. A dispersion was obtained. Further, 5.5 parts of a film-forming aid BDG was added to 100 parts of the emulsion particles to prepare an aqueous coating material for evaluation.

[Example 5 ]
Using emulsion B and emulsion C having the composition shown in Table 1, and adjusting the pH to 8 with 28% aqueous ammonia solution after polymerization, 1.4 parts of adipic acid dihydrazide was dispersed in 3 parts of deionized water. A dispersion liquid of emulsion particles was obtained in the same manner as in Example 1 except for adding the above. An aqueous coating material for evaluation was prepared by adding 5 parts of a film-forming aid BDG to 100 parts of the emulsion particles.

[Example 6 ]
First, 22 parts of SiEm charged into the flask was used, and the emulsion B and the emulsion C having the composition shown in Table 1 were used. After the polymerization was completed, the pH was adjusted to 8 with a 28% aqueous ammonia solution. A dispersion of emulsion particles was obtained in the same manner as in Example 1 except that 5 parts of a dispersion of 0.7 part of adipic acid dihydrazide was added. In addition, 4 parts of a film-forming auxiliary BDG was added to 100 parts of the emulsion particles to prepare an aqueous coating material for evaluation.

[Comparative Example 1]
Dispersion of emulsion particles in the same manner as in Example 1 except that 85 parts of deionized water and 0 part of SiEm initially charged in the flask were used, and emulsion B and emulsion C having the composition shown in Table 2 were used. Got. Further, 5.5 parts of a film-forming aid BDG was added to 100 parts of the emulsion particles to prepare an aqueous coating material for evaluation.

[Comparative Example 2]
A dispersion of emulsion particles was obtained in the same manner as in Example 1 except that the emulsion B and the emulsion C having the composition shown in Table 2 were used. Nine parts of film forming aid BDG was added to 100 parts of the emulsion particles to prepare an aqueous coating material for evaluation.

[Comparative Example 3]
Emulsion B and Emulsion C having the composition shown in Table 2 were used, the dropping time of the remaining emulsion B was 0.75 hours, and the dropping time of emulsion C was 1.75 hours. Other conditions were the same as in Example 1 to obtain a dispersion of emulsion particles. Further, 5 parts of a film-forming auxiliary BDG was added to 100 parts of the emulsion particles to prepare an aqueous coating material for evaluation.

The aqueous coating material was evaluated according to the following method.
[Evaluation of blocking resistance (high temperature drying)]
An aqueous coating material for evaluation was coated on a glass plate with a 6 mil applicator (80 mm long × 80 mm wide) and forcedly dried at 130 ° C. for 5 minutes. Next, after cooling to 50 ° C, gauze is placed on the surface of the coating film in an atmosphere of 50 ° C, and a weight previously heated to 50 ° C is placed thereon, and a load of 1.4 kg / cm ² is applied for 30 minutes. It was. Next, after cooling to room temperature, the gauze was slowly peeled off, and the difficulty of peeling and the traces of the gauze were visually observed and evaluated according to the following criteria.
A: When the glass plate is tilted, the gauze falls naturally and almost no trace of gauze remains on the coating film.
○: The gauze does not fall naturally even when the glass plate is tilted, but there is almost no trace of gauze remaining on the coating film.
Δ: The gauze does not fall naturally even when the glass plate is tilted, but it can be peeled off with a little force, and some traces of gauze remain.
X: When peeling gauze, a part of coating film also peeled and the trace of gauze remains clearly.

[Evaluation of blocking resistance (low temperature drying)]
Evaluation was carried out by the same method and evaluation criteria as in the above-described evaluation of blocking resistance (high temperature drying), except that the temperature for forced drying for 5 minutes was set to 50 ° C. after coating the aqueous coating material for evaluation on a glass plate. .

[Evaluation of frost resistance]
White enamel paint (pigment weight concentration 40%) using Dianal LX-1010 (manufactured by Mitsubishi Rayon Co., Ltd.) as a sealer on a gypsum slag perlite plate (thickness 12 mm x length 150 mm x width 70 mm) with a coating weight of 90 It was spray-coated at room temperature so as to be ˜100 g / m ² (wet mass) and dried at 130 ° C. for 5 minutes. Next, a white enamel paint (pigment weight concentration 40%) using Dianal LX-2011 (manufactured by Mitsubishi Rayon Co., Ltd.) as an intermediate coating layer on the sealer was applied in an amount of 90 to 100 g / m ² (wet). (Mass) was spray-coated at room temperature and dried at 130 ° C. for 5 minutes. Next, an aqueous coating material for evaluation is spray-coated on the intermediate coating layer as a top coating layer at room temperature so that the coating amount is 50 to 60 g / m ² (wet mass), and dried at 130 ° C. for 5 minutes. A test plate was prepared. The test plate was allowed to stand at room temperature for one day, and then the side and back surfaces of the test plate were sealed using a solvent-based two-component curable acrylic resin to provide a waterproof function. After one day, the frost damage resistance test was conducted with a freeze-thaw tester. Freezing and thawing conditions were a cycle test of −20 ° C./2 hours (in air) and 20 ° C./2 hours (in water).
The number of cycles until the test plate was cracked was measured using a 30-fold magnifier and evaluated according to the following criteria.
A: Cracks do not occur even after 300 cycles.
○: Cracks occur in 200 to 300 cycles.
Δ: Cracks occur in 100 cycles to 199 cycles.
X: Cracks occur by 99 cycles.

[Evaluation of smoothness]
An aqueous coating material for evaluation was coated on a glass plate with an 8 mil applicator (length 100 mm x width 15 mm), forcedly dried at 130 ° C for 2 minutes, and then visually checked for "more" and "mad cracks" on the coating film And evaluated according to the following criteria.
A: “More” and “Mad crack” are hardly seen, and a continuous coating film is formed.
○: Some “mud cracks” are observed at the edge of the paint film.
Δ: “Mad crack” is observed, but less than 50% with respect to the longitudinal direction of the painted surface.
X: “Mud crack” of 50% or more with respect to the vertical direction of the painted surface is observed.

[Evaluation of water resistance]
An aqueous coating material for evaluation was coated on a glass plate with a 4 mil applicator (length 80 mm × width 80 mm), and forcedly dried at 130 ° C. for 5 minutes. Subsequently, it was left to cool to room temperature. Thereafter, the glass plate was immersed in warm water at 50 ° C. for 100 hours, and the appearance of the coated film immediately after being pulled up and dried was visually observed and evaluated according to the following criteria.
(Double-circle): The whitening of the coating surface was little and it became a clear coating completely after drying.
◯: Some whitening of the painted surface was observed, but after drying, a clear coating film was formed in about 2 to 3 hours.
Δ: Some whitening of the painted surface was observed, and it was slightly cloudy even after 24 hours of drying, and a clear coating film was formed after 48 hours.
X: The painted surface was considerably whitened and remained white after drying, and did not become a clear coating film until the end.

[Evaluation of weather resistance]
Similar to the one used for the evaluation of frost damage resistance, the test plate with the side and back surfaces sealed is used, and after one day of sealing, the die plastic metal weather KU-R4-W type (manufactured by Daipura Wintes Co., Ltd.) is used. The weather resistance test was conducted. Test cycle: irradiation 4 hours (spray 5 seconds / 15 minutes) / condensation 4 hours, UV intensity: 85 mW / cm ² , black panel temperature: 63 ° C. during irradiation / 30 ° C. during condensation, humidity: 50% RH / during irradiation After 840 hours under the condition of 96% RH at the time of condensation, the gloss retention at a measurement angle of 60 ° was used as an indicator of weather resistance and evaluated according to the following criteria.
A: 90% or more.
○: 80% or more and less than 90%.
Δ: 60% or more and less than 80%.
X: Less than 60%, or with peeling / cracking of the coating film.
The results of the evaluation as described above are shown in Table 3.

In the aqueous coating material of Example 1, the ratio of the monomer (d) in the monomer (b) is 75 mass%, and the monomer (b) of methyl methacrylate in the monomer (b). And the ratio of the monomer (c) to the total mass is 30.5% by mass, and other conditions are optimal. In the aqueous coating material of Example 1, the coating film had good blocking resistance and high frost damage resistance, smoothness, water resistance, and weather resistance. Similar results were obtained in Example 2 and Example 3.
In addition, in the aqueous coating material of the reference example in which the ratio of the monomer (e) in the monomer (c) is 47% by mass and the other conditions are optimal, the coating film has high blocking resistance, It had good frost damage resistance, smoothness, water resistance, and weather resistance.
Moreover, the aqueous | water-based Example 4 whose mass ratio with respect to the total mass of a polymer (B) and a polymer (C) of a polyorganosiloxane polymer (A) is 1 mass%, and other conditions are optimal. In the coating material, the coating film had high blocking resistance, frost resistance, smoothness, water resistance, and good weather resistance.
Moreover, in the aqueous coating material of Example 5 and Example 6 in which all conditions are optimal, the coating film had high blocking resistance, frost damage resistance, smoothness, water resistance, and weather resistance.
As described above, the coating film using the aqueous coating material of the present invention has excellent performances in all of blocking resistance, frost resistance, smoothness, water resistance, and weather resistance.

On the other hand, in the aqueous coating material of Comparative Example 1 that does not use the polyorganosiloxane polymer (A), the coating film has extremely low frost damage resistance, smoothness, water resistance, and weather resistance. Moreover, in the aqueous | water-based coating material of the comparative example 2 whose ratio of the monomer (d) in a monomer (b) is 70 mass%, a coating film becomes very low in blocking resistance. Moreover, although the ratio of the monomer (d) in the monomer (b) is 100% by mass, the methyl methacrylate in the monomer (b) is replaced with the monomer (b) and the monomer (c ) Even with the aqueous coating material of Comparative Example 3 that is 28% by mass with respect to the total mass of (), the coating film has very low blocking resistance.
As described above, in the aqueous coating materials of Comparative Examples 1 to 3, the coating film did not satisfy the blocking resistance, the frost damage resistance, the smoothness, the water resistance, and the weather resistance at the same time.

  The aqueous coating material of the present invention is made of various materials such as cement mortar, slate board, gypsum board, extruded board, foamable concrete, metal, glass, porcelain tile, asphalt, wood, waterproof rubber material, plastic, calcium silicate base material, etc. It is useful as a surface finish coating material, and particularly useful as a water-based coating material for protecting buildings such as buildings and civil engineering structures.

Claims (2)

In an aqueous dispersion containing the polyorganosiloxane polymer (A), the ethylenically unsaturated monomer (b) is emulsion polymerized in one or more stages to form a polymer (B), and then the ethylenically unsaturated monomer is used. An aqueous coating material containing emulsion particles obtained by adding a saturated monomer (c) and emulsion polymerization to form a polymer (C),
The ethylenically unsaturated monomer (b) contains 75 to 100% by mass of the ethylenically unsaturated monomer (d) having a solubility parameter (SP value) of 20 to 30 (J / cm ³ ) ^1/2. And
The methyl methacrylate contained in the ethylenically unsaturated monomer (b) as the ethylenically unsaturated monomer (d) is different from the ethylenically unsaturated monomer (b) used in the emulsion polymerization. relative to the combined weight of the unsaturated monomer (c), Ri der least 30 mass%,
The ethylenically unsaturated monomer (c) includes an ethylenically unsaturated monomer (e) having a solubility parameter (SP value) of less than 20 (J / cm ³ ) ^1/2 , mass percentage aqueous coating material, wherein 65 to 100% by mass Rukoto of mer ethylenically unsaturated monomer contained in (c) (e). On the outside of the layer containing the polyorganosiloxane polymer (A) and the polymer (B) of the ethylenically unsaturated monomer (b), the polymer (C) of the ethylenically unsaturated monomer (c) is provided. An aqueous coating material comprising multi-layered emulsion particles,
The polymer (B) contains 75 to 100% by mass of polymerized units of an ethylenically unsaturated monomer (d) having a solubility parameter (SP value) of 20 to 30 (J / cm ³ ) ^1/2. ,
The methyl methacrylate polymer unit contained in the polymer (B) as the ethylenically unsaturated monomer (d) is a polymer unit of the polymer (B) and the polymer (C). based on the total weight of the body (b) an ethylenically unsaturated monomer and (c), Ri der least 30 mass%,
The polymerized units of the ethylenically unsaturated monomer (c) include polymerized units of the ethylenically unsaturated monomer (e) having a solubility parameter (SP value) of less than 20 (J / cm ³ ) ^1/2. , aqueous coating, wherein the mass ratio is 65 to 100% by mass Rukoto of polymerized units of ethylenically unsaturated monomer contained in the polymerized units of an ethylenically unsaturated monomer (c) (e) Wood.