JP5336816B2 - Aqueous coating material and method for producing emulsion - Google Patents

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.

  In recent years, in the field of paints used for buildings and civil engineering structures, solvent-based paints that use volatile organic compounds (hereinafter referred to as “VOC”) as solvents in consideration of the health and environmental protection of painters and local residents. To water-based paints using water as a dispersion medium. However, the emulsion resin used for the water-based emulsion paint that typifies the water-based paint has an inherent minimum film-forming temperature (hereinafter referred to as “MFT”), and the film is formed at a temperature below the MFT to form a coating film. In some cases, it was necessary to add VOC as a film-forming aid.

  On the other hand, in order to prevent blocking that tends to occur when coating plates are stacked, it is necessary to use a high-hardness resin as a binder, but the coating film of a coating material using a high-hardness resin has a problem with frost resistance. Moreover, since MFT is also high, it is necessary to mix | blend a film forming adjuvant in large quantities. Therefore, the water-based emulsion paint also contains a considerable amount of VOC, and when the drying after coating is insufficient, there is a problem that the blocking resistance and water resistance of the coating film deteriorate due to the remaining VOC. Then, examination of the water-based coating material which forms a coating film which has blocking resistance and frost damage resistance, and favorable water resistance and a weather resistance is performed.

  For example, Patent Document 1 discloses an acrylic copolymer obtained by copolymerizing a polyfunctional monomer having at least one allyl group as a resin composition that forms a coating film excellent in dispersion stability, alcohol shock resistance, and water resistance. A resin composition is disclosed. However, since it contains a solvent, it cannot be used as an aqueous coating material, and since the acid value is very high, there is a problem that the water resistance and weather resistance of the coating film are low when used for exterior applications.

Patent Document 2 discloses a resin composition that forms a coating film excellent in flexibility, melt flowability and transparency, and has a core / shell structure and graft bonding properties such as triallyl isocyanurate and allyl methacrylate. An acrylic resin composition obtained by copolymerizing a polyfunctional vinyl monomer is disclosed. However, since the hydrophilicity of the inner layer is high, there is a problem that the water resistance of the coating film is lowered when used for exterior applications.
JP 2006-316185 A Japanese Patent Laid-Open No. 7-10937

  An object of the present invention is to provide an aqueous coating material that forms a coating film excellent in blocking resistance, water resistance and weather resistance.

The first gist of the present invention is to form a polymer by emulsion polymerization of a mixture (a) containing an ethylenically unsaturated monomer, and then to form an ethylenically unsaturated monomer having a composition different from that of the mixture (a). A water-based coating material mainly composed of an emulsion obtained by adding a mixture (b) containing a monomer and forming a polymer by emulsion polymerization,
The mixture (a) containing an ethylenically unsaturated monomer contains an ethylenically unsaturated monomer (a1) having two or more allyl groups, and a solubility parameter (SP value) of 20 to 25 (J / cm ³ ) A water-based coating material containing 75% by mass or more of ^1/2 ethylenically unsaturated monomer (a2).

The second gist of the present invention is to form a polymer by emulsion polymerization of a mixture (a) containing an ethylenically unsaturated monomer, and then to form an ethylenically unsaturated monomer having a composition different from that of the mixture (a). A method for producing an emulsion by adding a mixture (b) containing a monomer and forming a polymer by emulsion polymerization,
The mixture (a) containing an ethylenically unsaturated monomer contains an ethylenically unsaturated monomer (a1) having two or more allyl groups, and a solubility parameter (SP value) of 20 to 25 (J / cm ³ ) A method comprising 75% by mass or more of ^1/2 ethylenically unsaturated monomer (a2).

  The present invention can provide an aqueous coating material that forms a coating film excellent in blocking resistance, water resistance and weather resistance.

Mixture containing ethylenically unsaturated monomer (a)
In the present invention, the mixture (a) containing an ethylenically unsaturated monomer (hereinafter referred to as “monomer (a)”) is an ethylenically unsaturated monomer (a1) having two or more allyl groups. (Hereinafter referred to as “monomer (a1)”) and an ethylenically unsaturated monomer (a2) having a solubility parameter (SP value) of 20 to 25 (J / cm ³ ) ^1/2 ( Hereinafter, it is essential to include “monomer (a2)”. The mixture (a) is polymerized to become an inner layer of emulsion particles or a free polymer.

  The monomer (a1) is a component that forms a crosslinked structure to improve the blocking resistance, water resistance, and weather resistance of the coating film. For example, triallyl cyanurate, triallyl isocyanurate, iso (tere) phthalic acid Examples include diallyl, diallyl isocyanurate, and diallyl maleate. Of these, triallyl cyanurate and triallyl isocyanurate having three allyl groups are preferable from the viewpoint of water resistance and weather resistance.

  Since monomer (a1) has two or more allyl groups having relatively slow radical polymerization reactivity, ethylene glycol dimethacrylate, allyl (meth) acrylate, divinylbenzene, tris (2-acryloyloxyethylene) isocyanurate, etc. Compared with a monomer having two or more radically polymerizable groups which are not allyl groups, a coating film having excellent blocking resistance, water resistance and weather resistance can be obtained.

  Further, the content of the monomer (a1) is preferably 0.1 to 10% by mass in the total monomer (hereinafter, simply referred to as “total monomer”) subjected to emulsion polymerization, 2 to 8% by mass is more preferable, and 0.5 to 8% by mass is still more preferable. When the content is 0.1% by mass or more, the blocking resistance, water resistance, and weather resistance of the coating film are improved, and when the content is 10% by mass or less, the decrease in film formability and coating film elongation can be suppressed.

  In the present invention, the SP value refers to a value obtained by the Fedors equation (R. F. Fedors, Polym. Eng. Sci., 14, (2), 1974) described in the following equation (1).

  The monomer (a) contains the monomer (a2) in an amount of 75% by mass or more, preferably 80% by mass or more.

  When the monomer (a2) is 75% by mass or more, the compatibilization of the polymer component derived from the monomer (a) and the polymer component derived from the polymer (b) is suppressed, and the monomer (a) The derived polymer component can impart hydrophilicity and improve blocking resistance, and the polymer component derived from the monomer (b) can impart hydrophobicity and improve weather resistance. Moreover, when the polymer component derived from the monomer (a) is increased in Tg, the blocking resistance of the coating film can be improved without reducing the frost damage resistance of the coating film.

  Examples of the monomer (a2) include methyl (meth) acrylate, ethyl acrylate, propyl acrylate, cyclohexyl acrylate, benzyl acrylate, phenyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl (meth) acrylate, 4- Examples thereof include 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.

  In addition, as the monomer (a), an ethylenically unsaturated monomer having an SP value of more than 25, such as 2-hydroxyethyl acrylate, acrylic acid, itaconic acid, acrylonitrile and the like can be used.

  Moreover, it is preferable to contain 25 mass% or more of methyl methacrylate in the whole monomer in terms of blocking resistance of the coating film. More preferably, it is 30 mass% or more. Moreover, 65 mass% or less is preferable at the surface of the frost damage resistance of a coating film.

  The Tg of the polymer component derived from the monomer (a) is preferably 50 to 150 ° C, 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 component derived from the monomer (a) to 50 to 150 ° C., the monomer (a) includes, in addition to methyl methacrylate, isobornyl (meth) acrylate, t-butyl methacrylate, cyclohexyl methacrylate. , Ethylenically unsaturated monomers such as (meth) acrylic acid 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 and the like, From the viewpoint of easy compatibilization of the polymer component derived from a) and the polymer component derived from monomer (b), and from the viewpoint of frost damage resistance of the coating film, it is preferable to suppress the amount used. In addition, when a highly hydrophilic ethylenically unsaturated monomer such as (meth) acrylic acid is used as the monomer (a), stability in the polymerization process, water resistance of the coating film, and weather resistance From the viewpoint of the above, it is preferable to limit the amount used.

  Tg is a value obtained by the Fox equation shown in Equation (2).

1 / (273 + Tg) = Σ (W _i / (273 + Tg _i )) (2)
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 amount of the monomer (a) used is preferably 20 to 70% by mass, more preferably 30 to 65% by mass based on the total amount of monomers. If the usage-amount is 20 mass% or more, the blocking resistance of a coating film will become high. Moreover, if the usage-amount 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 the ethylenically unsaturated monomer (excluding the monomer (a1)) having at least one in the monomer (a), more advanced coating properties and coating properties can be expressed. These monomers can use 2 or more types as needed.

  By incorporating hydroxylalkyl (meth) acrylate in the monomer (a), it is possible to improve the blending stability when producing an aqueous coating material, stain resistance, weather resistance, water resistance, and various undercoats of the coating film. Adhesion can be improved. It is preferable that the usage-amount of the hydroxyalkyl (meth) acrylate in all the monomers is 0.1-15 mass%, and 0.5-12 mass% is more preferable. If the ratio in all the monomers is 0.1% by mass or more, the above performance is improved, and if it is 15% by mass or less, the decrease in water resistance and weather resistance of the coating film can be suppressed.

  By containing a self-crosslinkable functional group-containing ethylenically unsaturated monomer in the monomer (a), the coating film has blocking resistance, stain resistance, weather resistance, water resistance, and adhesion to various substrates. Can be improved. The amount of the self-crosslinkable functional group-containing ethylenically unsaturated monomer used is preferably from 0.1 to 15% by mass, more preferably from 0.5 to 12% by mass, based on all monomers. If the amount used is 0.1% by mass or more, the above performance is improved, and if it is 15% by mass or less, deterioration of water resistance and weather resistance of the coating film 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.

  Moreover, the anti-blocking of a coating film is made by containing the ethylenically unsaturated monomer (except for monomer (a1)) which has two or more polymerizable unsaturated double bonds in monomer (a). , Water resistance and weather resistance can be improved. It is preferable that content of the said ethylenically unsaturated monomer is 0.1-10 mass% in all the monomers, and 0.2-8 mass% is more preferable. If content is 0.1 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 (excluding the monomer (a1)) include divinylbenzene, ethylene glycol di (meth) acrylate, and propylene glycol di (meta). ) Acrylate, butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, tris (2-acryloyloxyethylene) isocyanurate, and the like. Two or more of these may be selected and used as necessary.

  The polymer component derived from the monomer (a) can be produced by emulsion polymerization.

  For the emulsion polymerization, for example, a known method in which the monomer (a) 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 -Imidazoline 2-yl] propane} and salts thereof, 2,2′-azobis (2-methylpropionamidine) and salts thereof, 2,2′-azobis (2-methylpropyneamidine) and salts thereof, 2,2′- And azobis [N- (2-carboxyethyl) -2-methylpropionamidine] and salts thereof.

  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 (a), but 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 component derived from the monomer (a), n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, n-tetradecyl mercaptan is used as a molecular weight adjusting agent when polymerizing. Mercaptans such as n-hexyl mercaptan, 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 (a).

  Moreover, it is preferable that 0.1-10 mass parts of surfactant is contained in monomer (a) with respect to 100 mass parts of monomers (a), 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 (a), the polymerization stability and storage stability of the obtained 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.

  The viewpoint of obtaining a highly smooth coating film without causing a phenomenon called “more” that shrinks the formed coating film during drying after coating or a phenomenon called “mud crack” in which the coating film cracks. From the viewpoint of lowering the foamability of the resulting emulsion particle dispersion, 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.

Mixture containing ethylenically unsaturated monomer (b)
After the mixture (a) is emulsion-polymerized to form a polymer, the mixture (b) containing an ethylenically unsaturated monomer having a composition different from that of the monomer (a) (hereinafter referred to as “monomer (b)”) ”) And emulsion polymerization to obtain a polymer. The mixture (b) is polymerized into an outer layer of emulsion particles or a free polymer. The mixture (b) has a composition different from that of the mixture (a), so that the emulsion particles to be formed are composed of polymer components having different compositions. Therefore, the mixture (b) is excellent in blocking resistance, water resistance and weather resistance.

The monomer (b) 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 ( Hereinafter, it is preferable to contain “monomer (b1)”. 50-100 mass% is preferable and, as for content of the monomer (b1) contained in a monomer (b), 55-95 mass% is more preferable. If the ratio of a monomer (b1) is 50 mass% or more, since water absorption resistance will improve, the water resistance of a coating film, a weather resistance, and frost damage resistance will improve, and smoothness will also become high. In order to increase the smoothness of the coating film, it is more preferable to use a monomer (b1) having an SP value of 19.5 or less.

  Examples of the monomer (b1) 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. 19.0 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 component derived from the monomer (b) is preferably −50 to 50 ° C., and more preferably −30 to 30 ° C. When Tg of the polymer component derived from the monomer (b) is −50 ° C. or higher, blocking resistance and stain resistance of the coating film can be obtained. In addition, if the Tg of the polymer component derived from the monomer (b) is 50 ° C. or less, the film-forming property is improved, and even if the drying after coating is insufficient, the coating film remains resistant to blocking by VOC. Adverse effects on water resistance, water resistance and frost resistance.

  Moreover, it is preferable that it is 30-80 mass%, and, as for the usage-amount of the monomer (b) in the emulsion particle | grains obtained on the basis of the total monomer amount, it is more preferable that it is 35-70 mass%. If the amount of the monomer (b) used is 30% by mass or more, the frost damage resistance, smoothness, water resistance and weather resistance of the coating film are increased. Improves.

  Further, in order to develop the high-level coating properties and coating properties as described below, the monomer (b) 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 t-butyl methacrylate and / or cyclohexyl methacrylate is contained in the monomer (b), the weather resistance and water resistance of the coating film are improved. The content of t-butyl methacrylate and / or cyclohexyl methacrylate in all monomers 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 (b) 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 all monomers is preferably 0.05 to 15% by mass, more preferably 0.1 to 12% by mass. . 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 preferred are chlorosilane, γ-methacryloyloxyethyltrichlorosilane, γ-methacryloyloxypropylmethyldichlorosilane, and γ-methacryloyloxypropyltrichlorosilane.Moreover, these can also select and use 2 or more types as needed.

  If the monomer (b) contains an ethylenically unsaturated carboxylic acid, the storage stability of the dispersion of emulsion particles, and the stability of blending when pigments and additives are added to the dispersion of emulsion particles Improves. The content of the ethylenically unsaturated carboxylic acid in all monomers 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 said performance will improve, 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 hydroxyalkyl (meth) acrylate is contained in the monomer (b), 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 is improved. The content of hydroxyalkyl (meth) acrylate in all monomers 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 above performance is sufficiently improved, and by setting the content to 15% by mass or less, it is possible to suppress a decrease in water resistance and weather resistance of the coating film.

  If a polyoxyalkylene group-containing (meth) acrylate is contained in the monomer (b), the mixing stability of the emulsion particle dispersion, the stain resistance of the coating film, the weather resistance, the water resistance, and the coating film Adhesion to various bases is improved. The content of the polyoxyalkylene group-containing (meth) acrylate in all monomers 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 (b) 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. 0.1-15 mass% is preferable and, as for content of the self-crosslinkable functional group containing ethylenically unsaturated monomer in all the monomers, it is more preferable that it is 0.5-12 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 (a) 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 (b), the weather resistance of the coating film is improved. 0.1-20 mass% is preferable and, as for content of the ultraviolet-resistant ethylenically unsaturated monomer in all the monomers, it is more preferable that it is 0.2-15 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 all monomers, 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 monofluoroacetic acid metal (meth) acrylate, propionic acid metal (meth) acrylate, octylic acid metal (meth) acrylate, versatic acid metal (meth) acrylate, and isostearic acid metal. (Meth) acrylate, metal palmitate (meth) acrylate, metal cresotate (meth) acrylate, α-naphthoic acid metal (meth) acrylate, β-naphthoic acid metal (meth) acrylate, benzoic acid metal (meth) acrylate, 2 , 4,5-Trichlorophenoxyacetic acid metal (meth) acrylate, 2,4-dichlorophenoxyacetic acid metal (meth) acrylate, quinolinecarboxylic acid metal (meth) acrylate, nitrobenzoic acid metal (meth) acrylate, nitronaphthalenecarboxylic acid metal (Meth) acrylate, metal (meth) acrylate of puruvate, and the like, and examples of the metal include magnesium, calcium, iron, copper, zinc, and zirconium. 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 all the monomers is preferably 0 to 10% by mass, and more preferably 0.1 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 (b) 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. When an organic hydrazine compound having a hydrazino group (hereinafter referred to as “hydrazine compound”) is blended, the coating film has blocking resistance, frost resistance, water resistance, weather resistance, stain resistance, solvent resistance, and coating film. Adhesiveness to various bases improves. 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 all the monomers is preferably 0.2 to 10% by mass, and preferably 0.5 to 8% by mass. More preferred. 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.

  The polymer component derived from the monomer (b) is produced by carrying out one or more steps of emulsion polymerization, but is preferably produced by a two or more steps of multi-stage polymerization method. In the case of multistage polymerization, the monomer composition used for polymerization in each stage can be changed as necessary.

  In the production of the polymer component derived from the monomer (b), a polymerization initiator, a surfactant and a chain transfer agent can be used in the same manner as in the production of the polymer component derived from the monomer (a). The amount of the surfactant used is such that the total amount through the polymerization reaction for forming the monomer (a) and the monomer (b) is 0.1 to 10 parts by mass in the total monomers. Is preferred.

  In the aqueous coating material of the present invention, the monomer (a) is emulsion-polymerized to form a polymer, and then the monomer (b) is added, and the polymer is obtained by emulsion polymerization in one or more stages. Forming. Here, the step emulsion polymerization is repeated in two or more steps by a known emulsion polymerization method in an aqueous medium, but usually 2 to 5 step polymerization.

  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 basic compound. Furthermore, 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 30 to 300 nm and more preferably 50 to 130 nm in consideration of the balance between particle stability and coating film performance. If the polymerization conditions are such that the particle diameter is 30 nm or more, aggregates are unlikely to form during polymerization, and a small amount of surfactant may be used, so that the water resistance of the coating film can be maintained. Moreover, since it is hard to produce a film-forming defect at 300 nm or less and a film-forming property improves, the more excellent water resistance and weather resistance of a coating film can be exhibited.

  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 polymer component derived from the monomer (b) and the MFT of the emulsion particles is (MFT of the emulsion particles) ≦ (Tg + 30 ° C. of the polymer component derived from the monomer (b)). And (MFT of emulsion particles) ≦ Tg of polymer component derived from monomer (b) + 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 all the monomers. 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 the present invention described above, since the polymer component derived from the monomer (a) has a high hardness, it becomes a coating film having good blocking resistance. Further, the polymer component derived from the monomer (b) increases the frost damage resistance, smoothness, water resistance and weather resistance of the coating film. Further, the ethylenically unsaturated monomer (a1) having two or more allyl groups strengthens the bond between the polymer component derived from the monomer (a) and the polymer component derived from the monomer (b). Therefore, water resistance and weather resistance are further increased.

Hereinafter, the present invention will be described in detail with reference to examples. In the following description, “parts” and “%” are based on mass. The aqueous coating material was evaluated according to the following method.

<Preparation of aqueous coating material for evaluation (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 the dispersion of emulsion particles 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 adjusted by adding deionized water so that the viscosity was about 30 seconds in Ford Cup # 4. Thereafter, filtration was carried out using a 100 mesh nylon bag to obtain an aqueous coating material for evaluation.

<Evaluation method>
[Evaluation method]
In this example, a coating film was formed from the obtained aqueous coating material, and the blocking resistance, water resistance and weather resistance of the coating film were evaluated. Moreover, the particle diameter of the emulsion particles in the obtained aqueous coating material was measured.
(1) Blocking 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 100 ° C. for 20 minutes. Next, after cooling to 50 ° C., place gauze on the surface of the coating film in an atmosphere of 50 ° C., and place a weight that has been heated to 50 ° C. in advance, and apply a load of 3 kg / cm ² for 30 minutes. did. Next, after cooling to room temperature, the glass plate was slowly turned upside down to peel off the gauze, and the difficulty of peeling at that time and the trace of the gauze were visually observed and evaluated according to the following criteria. When removing the gauze, the gauze was peeled off by hand for the case where the gauze did not fall naturally.
A: The gauze falls naturally and almost no trace of gauze remains on the coating film.
○: The gauze does not fall naturally, but there is almost no trace of gauze remaining on the coating film.
(Triangle | delta): Although gauze does not fall naturally, it can peel with a little force and the trace of gauze remains a little.
X: When peeling gauze, a part of coating film also peeled and the trace of gauze remains clearly.
(2) Water resistance An aqueous coating material for evaluation was applied to a zinc phosphate-treated steel plate (bonderite # 100-treated steel plate, plate thickness 0.8 mm, length 150 mm × width 70 mm) with a bar coater # 48 at 130 ° C. Force-dried for 20 minutes. Subsequently, it was left to cool to room temperature. Thereafter, the zinc phosphate-treated steel sheet was immersed in hot water at 50 ° C. for 100 hours, and the appearance of the coating film was visually observed immediately after being pulled up and after a predetermined time had elapsed, and evaluated according to the following criteria.
A: The painted surface was not whitened, and a clear coating film (transparent appearance) was obtained immediately after pulling up.
◯: Some whitening of the painted surface was observed, but after clearing, a clear coating film was obtained in about 2 to 3 hours.
Δ: Some whitening of the painted surface was observed, and it was slightly turbid even after 24 hours from lifting, and after 48 hours barely became a clear coating film.
X: The painted surface was considerably whitened and remained white even after being pulled up, and did not become a clear coating film until the end.
(3) Weather resistance Using the same test plate as that used for the water resistance evaluation, a weather resistance test was performed with a die plastic metal weatherer KU-R4-W type (manufactured by Daipura Wintes Co., Ltd.). At this time, the test cycle was irradiation 4 hours (spray 5 seconds / 15 minutes) / condensation 4 hours, UV intensity: 65 mW / cm 2, black panel temperature: 63 ° C. during irradiation / 30 ° C. during condensation, humidity: 50% during irradiation Under the conditions of RH / 96% RH during condensation, the 60 ° gloss retention after 1200 hours and the color difference were used as weather resistance indicators, and evaluation was performed according to the following criteria.
A: Gloss retention 80% or more and less than 2 color difference
○: Gloss retention 70% or more and color difference 2 or more and less than 3 Δ: Gloss retention 60% or more and color difference 3 or more and less than 5 ×: Gloss retention 60% or less, or color difference 5 or more (4) Particle size Otsuka Electronics Measurement was performed at room temperature using a thick particle size analyzer FPAR-1000 manufactured by Co., Ltd., and calculation was performed by cumulant analysis.

<Example 1>
In a flask equipped with a stirrer, a reflux condenser, a temperature controller, and a dropping pump, deionized water: 110 parts by mass, New Coal 707SF (manufactured by Nippon Emulsifier Co., Ltd., solid content 30%): 5 parts by mass, A mixture of radically polymerizable monomers shown in "Monomer (a)" and Perbutyl H69 (manufactured by NOF Corporation): 0.02 parts by mass were charged. After raising the internal temperature of the flask to 40 ° C., ferrous sulfate: 0.0002 parts by mass / EDTA: 0.0005 parts by mass / sodium ascorbate: 0.12 parts by mass / deionized water: 6 parts by mass An aqueous reducing agent solution was added. After confirming the peak top temperature due to the polymerization exotherm, the internal temperature of the flask was maintained at 75 ° C.

  0.5 hours after addition of the reducing agent aqueous solution, a mixture of radical polymerizable monomers shown in “Monomer (b)” in Table 1, deionized water: 25 parts by mass, New Coal 707SF: 2.5 parts by mass Surfmer FP-120 (manufactured by Toho Chemical Co., Ltd.): 0.5 part by mass and 28% aqueous ammonia solution: pre-emulsion liquid emulsified and dispersed in advance and 0.17 part by mass perbutyl H69: 0.03 part by mass A polymerization initiator solution dissolved in 5 parts of deionized water was added dropwise over 2 hours. During this dropping, the internal temperature of the flask was kept at 75 ° C. After adding 1.25 parts by mass of 28% ammonia water, the mixture was cooled to room temperature, and 0.7 parts by mass of adipic acid dihydrazide and 1.5 parts by mass of deionized water were added to obtain a dispersion of emulsion particles.

  Using this emulsion particle dispersion, 12 parts of a film-forming aid BDG was added to 100 parts by mass of the emulsion particles to prepare an aqueous coating material for evaluation.

As shown in Table 3, the coating film had all the performances of blocking resistance, water resistance, and weather resistance.
<Example 2>
An aqueous coating material for evaluation was produced in the same manner as in Example 1 except that the amount of Newcol 707SF initially charged in the flask was 2.5 parts by mass.

As shown in Table 3, the coating film had all the performances of blocking resistance, water resistance, and weather resistance.
<Example 3>
An aqueous coating material for evaluation was prepared in the same manner as in Example 1 except that “monomer (b)” having the composition shown in Table 1 was used and that adipic acid dihydrazide / deionized water after room temperature cooling was not added. .

As shown in Table 3, the coating film had all the performances of blocking resistance, water resistance, and weather resistance.
<Examples 4-8, 11, 12>
An aqueous coating material for evaluation was produced in the same manner as in Example 1 except that the “monomer (a)” having the composition shown in Table 1 was used.

As shown in Table 3, the coating film had all the performances of blocking resistance, water resistance, and weather resistance.
<Example 9>
In a flask equipped with a stirrer, a reflux condenser, a temperature controller, a dropping pump, deionized water: 110 parts by mass, Adeka Soap SR-1025 (manufactured by Adeka Corp., solid content 25%): 6 parts by mass, table A mixture of radical polymerizable monomers shown in “Monomer (a)” of No. 1 and Perbutyl H69 (manufactured by NOF Corporation): 0.02 parts by mass were charged. After raising the internal temperature of the flask to 40 ° C., ferrous sulfate: 0.0002 parts by mass / EDTA: 0.0005 parts by mass / sodium ascorbate: 0.12 parts by mass / deionized water: 6 parts by mass An aqueous reducing agent solution was added. After confirming the peak top temperature due to the polymerization exotherm, the internal temperature of the flask was maintained at 75 ° C.

  0.5 hours after addition of the reducing agent aqueous solution, a mixture of radically polymerizable monomers shown in “Monomer (b)” in Table 1, deionized water: 25 parts by mass, Adeka Soap SR-1025: 3 parts by mass Part, Surfmer FP-120: 0.5 part by mass and 28% aqueous ammonia solution: pre-emulsion solution emulsified and dispersed in advance and 0.17 part by mass and perbutyl H69: 0.03 part by mass were dissolved in 5 parts of deionized water. The polymerization initiator solution was added dropwise over 2 hours. During the dropping, the internal temperature of the flask was kept at 75 ° C., and after the dropping was finished, the flask was further kept at 75 ° C. for 1.5 hours. After adding 1.25 parts by mass of 28% ammonia water, the mixture was cooled to room temperature, and adipic acid dihydrazide: 0.7 parts by mass / deionized water: 1.5 parts by mass was added to obtain a dispersion of emulsion particles.

  Using this emulsion particle dispersion, 12 parts of a film-forming aid BDG was added to 100 parts by mass of the emulsion particles to prepare an aqueous coating material for evaluation.

As shown in Table 3, the coating film had all the performances of blocking resistance, water resistance, and weather resistance.
<Example 10>
An aqueous coating material for evaluation was produced in the same manner as in Example 9 except that the “monomer (b)” having the composition shown in Table 1 was used.

As shown in Table 3, the coating film had all the performances of blocking resistance, water resistance, and weather resistance.
<Example 13>
An aqueous coating material for evaluation was produced in the same manner as in Example 1 except that the “monomer (b)” having the composition shown in Table 1 was used.

As shown in Table 3, the coating film had all the performances of blocking resistance, water resistance, and weather resistance.
<Comparative Examples 1-7>
An aqueous coating material for evaluation was prepared in the same manner as in Example 1 except that “monomer (a)” having the composition shown in Table 2 was used.

As shown in Table 4, the coating film was inferior in the physical property balance of blocking resistance, water resistance, and weather resistance.
<Comparative Example 8>
In a flask equipped with a stirrer, a reflux condenser, a temperature controller, and a dropping pump, deionized water: 100 parts by mass, New Coal 707SF: 4 parts by mass, radical polymerization shown in “Monomer (a)” in Table 1 A mixture of monomers, deionized water: 35 parts by mass, New Coal 707SF: 3.5 parts by mass, Surfmer FP-120: 0.5 parts by mass, and 28% aqueous ammonia solution: 0.17 parts by mass were previously emulsified and dispersed. 10% of the pre-emulsion solution and 0.02 part by weight of perbutyl H69 were charged. After raising the internal temperature of the flask to 40 ° C., ferrous sulfate: 0.0002 parts by mass / EDTA: 0.0005 parts by mass / sodium ascorbate: 0.12 parts by mass / deionized water: 6 parts by mass An aqueous reducing agent solution was added. After confirming the peak top temperature due to the polymerization exotherm, the internal temperature of the flask was maintained at 75 ° C.

  0.5 hours after addition of the reducing agent aqueous solution, the remaining pre-emulsion solution and a polymerization initiator solution in which 0.03 parts by mass of perbutyl H69 was dissolved in 5 parts of deionized water were added dropwise over 2 hours. During the dropping, the internal temperature of the flask was kept at 75 ° C., and after the dropping was finished, the flask was further kept at 75 ° C. for 1.5 hours. After adding 1.25 parts by mass of 28% ammonia water, the mixture was cooled to room temperature, and adipic acid dihydrazide: 0.7 parts by mass / deionized water: 1.5 parts by mass was added to obtain a dispersion of emulsion particles.

  Using this emulsion particle dispersion, 12 parts of a film-forming aid BDG was added to 100 parts by mass of the emulsion particles to prepare an aqueous coating material for evaluation.

As shown in Table 4, the coating film was inferior in the physical property balance of blocking resistance, water resistance, and weather resistance.

The abbreviations in the table are as follows.
TAC: triallyl cyanurate TAIC: triallyl isocyanurate MMA: methyl methacrylate GMA: glycidyl methacrylate 2-HEMA: 2-hydroxyethyl methacrylate t-BMA: t-butyl methacrylate CHMA: cyclohexyl methacrylate n-BMA: n-butyl methacrylate 2 -EHA: 2-ethylhexyl acrylate AA: acrylic acid DAAm: diacetone acrylamide EDMA: ethylene glycol dimethacrylate TMP-TMA: trimethylolpropane trimethacrylate FA-731A: tris (2-acryloyloxyethyl) isocyanurate (Hitachi Chemical Industries ( Made by Co., Ltd.)
AMA: Allyl methacrylate DVB: Divinylbenzene New Coal 707SF: Non-reactive anionic surfactant (manufactured by Nippon Emulsifier Co., Ltd.)
Surfmer FP-120: Phosphate ester type reactive surfactant (trade name, manufactured by Toho Chemical Industry Co., Ltd.)
ADEKA rear soap SR-1025: Reactive anionic surfactant (trade name, manufactured by ADEKA CORPORATION)
ADH: Adipic acid dihydrazide

Claims (2)

A mixture (a) containing an ethylenically unsaturated monomer is emulsion-polymerized to form a polymer, and then a mixture (b) containing an ethylenically unsaturated monomer having a composition different from that of the mixture (a) is formed. In addition, an aqueous coating material mainly composed of emulsion particles obtained by emulsion polymerization to form a polymer,
The mixture (a) containing an ethylenically unsaturated monomer contains an ethylenically unsaturated monomer (a1) having two or more allyl groups, and a solubility parameter (SP value) of 20 to 25 (J / cm ³ ) An aqueous coating material containing 75% by mass or more of ^1/2 ethylenically unsaturated monomer (a2). A mixture (a) containing an ethylenically unsaturated monomer is emulsion-polymerized to form a polymer, and then a mixture (b) containing an ethylenically unsaturated monomer having a composition different from that of the mixture (a) is formed. In addition, a method of producing an emulsion by emulsion polymerization to form a polymer,
The mixture (a) containing an ethylenically unsaturated monomer contains an ethylenically unsaturated monomer (a1) having two or more allyl groups, and a solubility parameter (SP value) of 20 to 25 (J / cm ³ ) A method comprising 75% by mass or more of ^1/2 ethylenically unsaturated monomer (a2).