JP2015143369A - Manufacturing method of emulsion and aqueous coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous coating material capable of forming a coated film excellent in blocking resistance, frost damage resistance, water resistance, mad crack resistance and weather resistance, and a manufacturing method of emulsion for obtaining the same.SOLUTION: There is provided a method by emulsion polymerizing an ethylenically unsaturated monomer (a) with one step or more in presence of an anionic surfactant (I) and a nonionic surfactant (II) to form a polymer (A), then adding ethylenically unsaturated monomer (b), and emulsion polymerizing to form a polymer (B) and there is provided an aqueous coating material where the ethylenically unsaturated monomer (a) contains an ethylenically unsaturated monomer (c) having a solubility parameter (SP value) of 20 to 30 (J/cm)of 75 to 100 mass% and the glass transition temperature (Tg) of the polymer (A) is 70 to 110°C.

Description

  The present invention relates to an emulsion production method and an aqueous coating material.

In recent years, in the field of paints used for buildings and civil engineering structures, a solvent using a volatile organic compound (hereinafter referred to as “VOC”) as a solvent in consideration of the health and environmental protection of the painter and surrounding residents. Conversion from water-based paints to water-based paints (water-based coating materials) using water as a dispersion medium has been attempted.
However, emulsion resins used in water-based emulsion paints, which are representative of water-based paints, have an inherent minimum film-forming temperature (hereinafter referred to as “MFT”), and are produced at temperatures below MFT 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 stacked | stacked, it is necessary to use high hardness resin as a binder. However, a coating film of a coating material using a high-hardness resin has a problem in frost damage resistance, and also has a high MFT, so it is necessary to add a large amount of a film-forming aid. Therefore, even if it is a water-based emulsion paint, a considerable amount of VOC is contained, and when the drying after coating is insufficient, the remaining VOC causes the blocking resistance and water resistance of the coating film to deteriorate. was there.

Furthermore, as a phenomenon peculiar to water-based emulsion paints, there is often a problem that so-called mud cracks occur such that the coating film is cracked by drying after painting. Mud cracks tend to occur when the coating film becomes thick or when it is forced to dry by applying temperature, and the coating film surface shrinks in volume as the solvent water evaporates, causing mud cracking. It is considered a thing. The occurrence of mud cracks not only impairs the appearance of the coating film but also contributes to a decrease in various performances such as water resistance and weather resistance.
Thus, studies have been made on water-based coating materials that form a coating film having blocking resistance, frost damage resistance, and water resistance, and having good mud crack resistance and weather resistance.

For example, Patent Document 1 discloses a resin composition that forms a coating film excellent in blocking resistance, low-temperature stability, and low-temperature film-forming properties, having a core / shell structure, and a polyethylene glycol chain or polypropylene glycol in the shell layer. A resin composition obtained by copolymerizing an ethylenically unsaturated monomer containing a chain is disclosed.
However, the introduction of polyethylene glycol chains or polypropylene glycol chains 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, the aqueous coating material containing the resin composition described in Patent Document 1 has a problem in mud crack resistance.

Patent Document 2 discloses a method for producing an aqueous coating material by producing an emulsion in which an anionic surfactant and a nonionic surfactant are used in combination to perform multistage emulsion polymerization.
However, since the method described in Patent Document 2 uses a large amount of anionic surfactant and nonionic surfactant, the resulting aqueous coating material does not necessarily satisfy the mud crack resistance.

  As described above, the conventional water-based paints did not sufficiently satisfy the blocking resistance, frost damage resistance, water resistance and weather resistance of the coating film. In addition, the mud crack resistance of the coating film is also 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 International Publication No. 2005/075583

  An object of the present invention is to provide an aqueous coating material capable of forming a coating film excellent in blocking resistance, frost damage resistance, water resistance, mud crack resistance and weather resistance, and a method for producing an emulsion for obtaining the aqueous coating material. provide.

The method for producing an emulsion of the present invention comprises emulsion polymerization of ethylenically unsaturated monomer (a) in one or more stages in the presence of anionic surfactant (I) and nonionic surfactant (II). A polymer (A) is formed, and then an ethylenically unsaturated monomer (b) having a composition different from that of the ethylenically unsaturated monomer (a) is added, followed by emulsion polymerization to form a polymer (B). It is a manufacturing method of the emulsion to form, Comprising: Mass ratio of the said anionic surfactant (I) and the said nonionic surfactant (II) is (I) :( II) = 3: 1 to 1: 4. And the total amount of the anionic surfactant (I) and the nonionic surfactant (II) is an ethylenically unsaturated monomer (a) and an ethylenically unsaturated monomer (b ) And a total mass of 100 parts by mass, 0.5 to 2.5 parts by mass, Ethylenic unsaturated monomer (a) is a solubility parameter (SP value) comprises 20~30 ^{(J /} cm ^{3) 1/2} of ethylenically unsaturated monomer (c) 75 to 100 wt% The glass transition temperature (Tg) of the polymer (A) is 70 to 110 ° C.

The ethylenically unsaturated monomer (c) contains at least methyl methacrylate, and the content of the methyl methacrylate is such that the ethylenically unsaturated monomer (a) used for the emulsion polymerization and the ethylenically unsaturated monomer It is preferably 30% by mass or more based on the total mass with the monomer (b).
Further, the total amount of the anionic surfactant (I) and the nonionic surfactant (II) is such that the ethylenically unsaturated monomer (a) and the ethylenically unsaturated monomer (b ) And the total mass of 100 parts by mass is preferably 0.5 to 1.5 parts by mass.

  The aqueous coating material of the present invention is characterized by containing an emulsion obtained by the method for producing an emulsion of the present invention.

According to the aqueous coating material of the present invention, a coating film excellent in blocking resistance, frost damage resistance, water resistance, mud crack resistance and weather resistance can be formed.
Moreover, according to the method for producing an emulsion of the present invention, it is possible to obtain an emulsion contained in an aqueous coating material capable of forming a coating film excellent in blocking resistance, frost resistance, water resistance, mud crack resistance and weather resistance. it can.

Hereinafter, the present invention will be described in detail.
[Method for producing emulsion]
The method for producing an emulsion of the present invention comprises emulsion polymerization of ethylenically unsaturated monomer (a) in one or more stages in the presence of anionic surfactant (I) and nonionic surfactant (II). This is a method in which the polymer (A) is formed, and then the ethylenically unsaturated monomer (b) is added, followed by emulsion polymerization to form the polymer (B). can get.

<Surfactant>
The mass ratio of the anionic surfactant (I) and the nonionic surfactant (II) used in the emulsion polymerization is (I) :( II) = 4: 1 to 1: 4. When the mass ratio is within the above range, the volume shrinkage of the coating film surface can be effectively suppressed and the occurrence of mud cracks can be prevented when the aqueous coating material containing the resulting emulsion is applied and dried. be able to.
The mass ratio is preferably (I) :( II) = 3: 1 to 1: 4, more preferably 2: 1 to 1: 4.

  Further, the total amount (solid content) of the anionic surfactant (I) and the nonionic surfactant (II) is the amount of the ethylenically unsaturated monomer (a) and the ethylenically unsaturated monomer used in the emulsion polymerization. It is 0.5-2.5 mass parts with respect to 100 mass parts of total mass with a body (b). When the total amount of the anionic surfactant (I) and the nonionic surfactant (II) is 0.5 parts by mass or more, the polymerization stability and storage stability of the emulsion are improved. On the other hand, if the total amount is 2.5 parts by mass or less, mud cracks that occur during drying after coating can be prevented. Furthermore, the stability at the time of forming a paint, the temporal stability of the paint, etc. can be maintained without impairing the water resistance of the coating film. This total amount is preferably 1.0 to 2.0 parts by mass, and more preferably 1.2 to 1.5 parts by mass.

  Examples of the anionic surfactant (I) include alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene polycyclic phenyl ether sulfates, alkyl benzene sulfonates, fatty acid salts, alkyl naphthalene sulfonates. Alkyl sulfosuccinic acid, alkyl diphenyl ether disulfonate, polyoxyethylene alkyl ether phosphate, naphthalene sulfonic acid formalin condensate, and other polymer surfactants. A reactive anionic surfactant having an ethylenically unsaturated bond in the surfactant component can also be used.

Among the anionic surfactants described above, the polyoxyethylene alkyl ether sulfate ester salt can be obtained as LATEMUL E-118B (trade name, manufactured by Kao Corporation).
The polyoxyethylene polycyclic phenyl ether sulfate ester salt can be obtained as Newcol 707SF (trade name, manufactured by Nippon Emulsifier Co., Ltd.). Furthermore, about a reactive anionic surfactant, it can be obtained as ADEKA rear soap SR-1025 and ADEKA rear soap SR-10 (trade name, manufactured by ADEKA Corporation). These may be used alone or in combination of two or more as required.

  Nonionic surfactant (II) includes, for example, polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene derivative, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester , Polyoxyethylene fatty acid ester, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkylamine, alkylalkanolamide and the like. A reactive nonionic surfactant having an ethylenically unsaturated bond in the surfactant component can also be used.

  Among the nonionic surfactants described above, polyoxyethylene alkyl ether can be obtained as Emulgen E-1150S-60 (trade name, manufactured by Kao Corporation). Moreover, about a reactive nonionic surfactant, it can be obtained as ADEKA rear soap ER-30 (trade name, manufactured by ADEKA Corporation). These may be used alone or in combination of two or more as required.

<Formation of polymer (A)>
The polymer (A) is an ethylenically unsaturated monomer (a) (hereinafter referred to as “monomer (a)” in the presence of the anionic surfactant (I) and the nonionic surfactant (II). Is obtained by emulsion polymerization in one or more stages. Monomer (a) may be one type of monomer or a mixture of plural types of monomers.
The monomer (a) is an ethylenically unsaturated monomer having a solubility parameter (SP value) of 20 to 30 (J / cm ³ ) ^1/2 (particularly those contained in the monomer (a)). An ethylenically unsaturated monomer (c), hereinafter referred to as “monomer (c)”) is preferably contained in an amount of 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 (i) of the atom or atomic group, and Δv _i (cm ³ / mol) is the atomic or atomic group (i). The molar volume of

The polymer (A) emulsion-polymerizes the monomer (a) containing 75 to 100% by mass of the monomer (c) having an SP value of 20 to 30 (J / cm ³ ) ^1/2 in one or more stages. Is preferably obtained. The ratio of the monomer (c) in the monomer (a) is more preferably 80 to 100% by mass. If the ratio of the monomer (c) in the monomer (a) is 75% by mass or more, the compatibilization between the polymer (A) and the polymer (B) described later can be suppressed, and the emulsion obtained Functional differentiation in each polymer layer becomes possible. Moreover, when making a polymer (A) into a high glass transition temperature (Tg), blocking resistance can be improved, without reducing the freezing damage resistance of a coating film.

  Examples of the monomer (c) 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. 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.

  From the viewpoint of blocking resistance of the coating film, the monomer (c) contained in the monomer (a) of the present invention is composed of the monomer (a) and an ethylenically unsaturated monomer described later. Based on the total mass of monomers (hereinafter simply referred to as “total monomer amount”) combined with the monomer (b), 30% by mass or more is preferably methyl methacrylate, and more preferably. Is 33% by mass or more. 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 (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.
“Tg” is a value obtained by the Fox equation shown in the following 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.

In order to set the Tg of the polymer (A) to 50 to 150 ° C., the monomer (a) 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 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 or the like is used, a polymer (A ) And the polymer (B) are preferably suppressed from being used from the viewpoint of the effect of suppressing the compatibilization of the polymer (B) and the frost damage resistance of the coating film. In addition, among monomers (c), when using a highly hydrophilic ethylenically unsaturated monomer such as (meth) acrylic acid, stability in the polymerization process, water resistance of the coating film, It is preferable to limit the amount used in terms of mud crack resistance and weather resistance.

  The content of the polymer (A) having a Tg of 50 to 150 ° C. in the emulsion is preferably 30 to 70% by mass with respect to the total monomer amount, and is preferably 35 to 65% by mass. More preferred. 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.

  In the method for producing an emulsion of the present invention, as shown below, a hydroxyalkyl (meth) acrylate, a self-crosslinkable functional group-containing ethylenically unsaturated monomer, and a polymerizable unsaturated double bond in the molecule. By containing two or more ethylenically unsaturated monomers in the monomer (a), more advanced coating properties and coating properties can be developed. These monomers can use 2 or more types as needed.

  By incorporating hydroxylalkyl (meth) acrylate in the monomer (a), blending stability when producing an aqueous coating material containing the resulting emulsion, stain resistance, weather resistance, water resistance of the coating film And adhesion to various bases can be improved. The mass proportion of the hydroxyalkyl (meth) acrylate in the monomer (a) is preferably from 0.1 to 15 mass%, more preferably from 0.5 to 12 mass%. The effect mentioned above will be acquired if the mass ratio in a monomer (a) 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 (a), 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 (a). If content is 0.1 mass% or more, the effect mentioned above will be acquired, 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.

  Here, “self-crosslinkable functional group-containing ethylenically unsaturated monomer” means that the self-crosslinkable functional group remaining in the obtained emulsion is chemically treated while the emulsion is stored as a dispersion at room temperature. This is a monomer that is chemically stable and reacts with the functional groups of the side chains by drying, heating, or other external factors during coating to form chemical bonds between the side chains.

  Examples of such self-crosslinkable functional group-containing ethylenically unsaturated monomers include oxirane group-containing ethylenically unsaturated monomers such as glycidyl (meth) acrylate, N-methylol (meth) acrylamide, and N-butoxymethyl. Examples include alkylols or alkoxyalkyl compounds of ethylenically unsaturated amides such as (meth) acrylamide and N-methoxymethyl (meth) acrylamide. Two or more of these may be selected and used as necessary.

  In addition, the monomer (a) 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 (a). 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 (meth) ) Acrylate, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, diallyl iso (tere) phthalate, diallyl isocyanurate, and the like. Two or more of these may be selected and used as necessary.

The polymer (A) can be produced by subjecting the monomer (a) to one or more emulsion polymerizations in the presence of the anionic surfactant (I) and the nonionic surfactant (II). 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 (a) are used, the monomer composition used for the polymerization at each stage may be different as necessary.
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 oil-soluble azo compounds include azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2 Examples include '-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile and the like.
Examples of 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 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 initiator. .

  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 (A), n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, n-tetradecyl mercaptan, n-hexyl is used as a molecular weight adjusting agent when polymerizing. Mercaptans such as 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 (a).

<Formation of polymer (B)>
The polymer (B) is obtained by emulsion polymerization of the monomer (a) to form the polymer (A), and then the ethylenically unsaturated monomer (b) ( Hereinafter, it is referred to as “monomer (b)”.
) And emulsion polymerization. Monomer (b) may be one type of monomer or a mixture of plural types of monomers.
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 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 (b) is an ethylenically unsaturated monomer (d), And monomer (d)). The mass ratio of the monomer (d) contained in the monomer (b) is preferably 40 to 100% by mass, and more preferably 45 to 100% by mass. If the ratio of a monomer (d) is 40 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. Moreover, it is more preferable to use monomer (d) whose SP value is 19.5 or less from the point of the mud crack resistance of a coating film.

  Examples of the monomer (d) include SP values 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 monomer, n-propyl methacrylate, i-butyl acrylate, n-butyl methacrylate, n-hexyl acrylate, isobornyl acrylate, α-methyl styrene, p-methyl styrene, SP value of 2-ethoxyethyl methacrylate, i-propoxyethyl acrylate, n-butoxyethyl acrylate, ethoxyethoxyethyl acrylate, dimethylaminoethyl methacrylate, etc. is 1 1.0 to 19.5 ethylenically unsaturated monomer, i-propyl methacrylate, t-butyl (meth) acrylate, i-butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) Examples thereof include 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 (B) is preferably −50 to 50 ° C., and more preferably −30 to 30 ° C. When Tg of the polymer (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 (B) is 50 ° C. or less, the film-forming property is high, and even when drying after coating is insufficient, the coating film has residual blocking resistance, water resistance and frost resistance due to VOC remaining. The adverse effect on sex is reduced.

  Moreover, it is preferable that content of the polymer (B) whose Tg is -50-50 degreeC in the obtained emulsion is 30-70 mass% on the basis of a total monomer amount, and 35-65 mass. % Is more preferred. If content of a polymer (B) is 30 mass% or more, the frost damage resistance, mud crack resistance, water resistance, and weather resistance of a coating film will become high. Moreover, if content of a polymer (B) 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 (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 (hereinafter simply referred to as “all monomers”) to be subjected to emulsion polymerization is preferably 5 to 70% by mass. 10 to 60% by mass is more preferable. When the content is 5% by mass or more, the weather resistance and water resistance of the coating film can be improved. When the content is 70% by mass or less, a decrease in frost resistance of the coating film can be suppressed.

  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, and when the content is 15% by mass or less, a decrease in frost resistance of the coating film can be suppressed.

Examples of the hydrolyzable silyl group-containing ethylenically unsaturated monomer include vinylsilanes such as vinylmethyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldichlorosilane, and vinyltrichlorosilane, and γ- (meta ) Acryloyloxyethylmethyldimethoxysilane, γ- (meth) acryloyloxyethyltrimethoxysilane, γ- (meth) acryloyloxyethyltriethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ- (meth) acryloyl Oxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxyethylmethyldichlorosilane, γ- (meth) acryloyloxyethyltrichlorosila And (meth) acryloyloxyalkylsilanes such as γ- (meth) acryloyloxypropylmethyldichlorosilane and γ- (meth) acryloyloxypropyltrichlorosilane.
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-methacryloyl. Oxyethyltrimethoxysilane, γ-methacryloyloxyethyltriethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-methacryloyloxyethylmethyldichlorosilane Γ-methacryloyloxyethyltrichlorosilane, γ-methacryloyloxypropylmethyldichlorosilane, and γ-methacryloyloxypropyltrichlorosilane are more preferable. There. 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 emulsion dispersion and the blending stability when a pigment or additive is added to the emulsion dispersion to form a paint improves. The content of the ethylenically unsaturated carboxylic acid in all monomers is preferably 0.1 to 2% by mass, and more preferably 0.1 to 1.5% by mass. More preferably, it is 0.1-1 mass%. If the content is 0.1% by mass or more, the effect obtained by adding the ethylenically unsaturated carboxylic acid is obtained. By setting the content to 2% by mass or less, the occurrence of mud cracks can be prevented, and coating is performed. A decrease in water resistance and weather resistance of the film can be suppressed.

  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, monohydroxyethyl oxalate (Meth) acrylate, monohydroxyethyl tetrahydrophthalate (meth) acrylate, monohydroxypropyl tetrahydrophthalate (meth) acrylate, 5-hydroxy-1,2-cyclohexanedicarboxylic acid monohydroxyethyl (meth) acrylate, monohydroxyphthalate Ethyl (meth) acrylate, monohydroxypropyl (meth) acrylate phthalate, monohydroxyethyl (meth) acrylate maleate, hydroxypropyl (meth) acrylate maleate 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 dispersion, the stain resistance of the coating film, the weather resistance, the water resistance, and the adhesion of the coating film to various substrates Improves. 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. 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 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 blending stability of the emulsion dispersion, the stain resistance of the coating, the weather resistance, the water resistance, and various types of coating Adhesion to the base 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, 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) mono 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 (polyethyleneoxide) -Propylene oxide) Mono (meth) acrylate and other alkyl group end-capped polyalkylene oxide group-containing groups Ren unsaturated monomers. Two or more of these may be selected and used as necessary.

When the monomer (b) contains a self-crosslinkable functional group-containing ethylenically unsaturated monomer, the stain resistance, weather resistance, water resistance, and adhesion of the coating film to various substrates are improved. To do. 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- And cyano-4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine.
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 (b) 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, examples of preferred organic acid residues include monochloroacetic acid, monofluoroacetic acid, propionic acid, and octylic 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, nitrobenzoic acid Examples thereof include those derived from monovalent organic acids such as acid, nitronaphthalenecarboxylic acid, and purvic acid.

  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, isostearic acid metal ( (Meth) acrylate, palmitic acid metal (meth) acrylate, cresotinate metal (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 ( Examples thereof include magnesium), calcium, iron, copper, zinc, and zirconium. These can be used by selecting two or more kinds as required. 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 0.1 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, and when the content is 10% by mass or less, deterioration of the water resistance and weather resistance of the coating film can be suppressed.

  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 hydrazinos in the molecule are contained in the emulsion dispersion. When an organic hydrazine compound having a 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 coating bases. Adhesion with respect to is improved. This effect is attributed to the fact that a crosslinking reaction proceeds between the carbonyl group in the emulsion and the hydrazino group of the hydrazine compound incorporated 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, and adipine. Dihydrazides of dicarboxylic acids having 2 to 15 carbon atoms such as dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, isophthalic acid dihydrazide, itaconic acid dihydrazide, and 1,3-bis (hydrazinocarboethyl) -5 -Isopropylhydantoin, 1,3-bis (hydrazinocarboethyl) -5- (2-methylmercaptoethyl) hydantoin, 1-hydrazinocarboethyl-3-hydrazinocarboisopropyl-5- (2-methylmercaptoethyl) Compounds having a hydantoin skeleton hydantoin and the like. 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 the carbonyl group and / or aldehyde group in the emulsion (P), and is added to the emulsion dispersion. When the number of moles of hydrazino group of the hydrazine compound is (Q), the ratio (P) / (Q) is preferably 0.1 to 10, more preferably 0.8 to 2. If (P) / (Q) is 0.1 or more, the 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 is crosslinked. The degree becomes higher, and the coating film has improved blocking resistance, frost damage resistance, water resistance, weather resistance, stain resistance, solvent resistance, and adhesion of the coating film to various substrates.

  In the production of the polymer (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 (A).

  In the method for producing an emulsion of the present invention, the emulsion polymerization of the polymer (A) and / or the emulsion polymerization of the polymer (B) is performed in an aqueous dispersion containing the polyorganosiloxane polymer (X). Is preferred. In particular, in an aqueous dispersion containing the polyorganosiloxane polymer (X), an ethylenically unsaturated monomer (a) is emulsion-polymerized in one or more stages to form a polymer (A), followed by It is preferred to add the ethylenically unsaturated monomer (b) and emulsion polymerize to form the polymer (B). Thereby, the aqueous | water-based coating | covering material which has the emulsion which has a different layer structure as a main component can express a more advanced weather resistance and coating-film physical property.

  The aqueous dispersion containing the polyorganosiloxane polymer (X) includes a polymer block (III) having an organosiloxane as a repeating unit, a polymer block (IV) having an ethylenically unsaturated monomer as a repeating unit, and Examples thereof include an aqueous resin dispersion of a graft block copolymer composed of a polymer block (III) and a silicon-containing graft crossing agent (V) copolymerized with the polymer block (IV).

The polymer block (III) constituting the graft block copolymer is composed of dimethyldialkoxysilanes such as dimethyldimethoxysilane and dimethyldiethoxysilane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane. , Dimethylsiloxane cyclic oligomers such as dodecamethylcyclohexasiloxane, tetradecamethylcycloheptasiloxane, dimethyl cyclic (dimethylsiloxane cyclic oligomer 3-7 mer mixture), dimethyldichlorosilane, etc. can be synthesized as raw materials. .
Considering performance such as the raw material price and the thermal stability of the resulting resin, the most suitable raw material for the polymer block (III) is a dimethylsiloxane cyclic oligomer.

  As the ethylenically unsaturated monomer used in the polymer block (IV) constituting the graft block copolymer, the above-mentioned various ethylenically unsaturated monomers are appropriately selected as necessary. Can be used. The polymer block (IV) is preferably contained within a range of 50 to 99.5 parts by mass in 100 parts by mass of the graft block copolymer. When the content of the polymer block (IV) is 50 parts by mass or more, the hardness, strength, and stain resistance of the cured film tend to be improved. Moreover, if it is 99.5 mass parts or less, it exists in the tendency which can suppress the fall of the flexibility of a cured film, water resistance, and weather resistance. A more preferable content is 60 to 99 parts by mass.

  Specific examples of the silicon-containing grafting agent (V) include vinyl silanes such as vinylmethyldimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane; γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane , Methacryloyloxyalkylsilanes such as γ-oxypropyltriethoxysilane; acryloyloxyalkylsilanes such as γ-acryloyloxypropyltrimethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropyltriethoxysilane; Mercapto such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane Rukirushiran the like; and the like. Among these, methacryloyloxyalkylsilanes, acryloyloxyalkylsilanes, and mercaptoalkylsilanes are particularly preferable in consideration of vinyl polymerization reactivity and cost. These may be used alone or in combination of two or more as required.

  The silicon-containing graft crossing agent (V) is preferably in the range of 0.5 to 50 mol% based on the total of 100 mol% of silicon atoms in the graft block copolymer. If this content is 0.5 mol% or more, the transparency of the cured film tends to be improved, and if it is 50 mol% or less, the performance of the cured film tends to be improved. A more preferable content is 1 to 15 mol%. If the content is 1 mol% or more, the transparency of the resulting cured film will be very good, and if it is 15 mol% or less, the latex stability during emulsion polymerization will be good.

  Moreover, in the manufacturing method of the emulsion of this invention, it is preferable to add a basic compound to the dispersion liquid of the obtained emulsion after emulsion polymerization, and to make pH into the range of 6.5-10.0. Thereby, stability can be improved. In particular, if the pH is 7.0 to 10.0, more excellent freeze-thaw stability can be imparted.

Examples of basic compounds include ammonia, triethylamine, propylamine, dibutylamine, amylamine, 1-aminooctane, 2-dimethylaminoethanol, ethylaminoethanol, 2-diethylaminoethanol, 1-amino-2-propanol, and 2-amino. -1-propanol, 2-amino-2-methyl-1-propanol, 3-amino-1-propanol, 1-dimethylamino-2-propanol, 3-dimethylamino-1-propanol, 2-propylaminoethanol, ethoxy Examples include propylamine, 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.

Thus, in the presence of the anionic surfactant (I) and the nonionic surfactant (II), the ethylenically unsaturated monomer (a) is emulsion-polymerized in one or more stages to obtain a polymer (A). After that, an ethylenically unsaturated monomer (b) is added and emulsion polymerization is performed to form a polymer (B), whereby an emulsion is obtained.
The emulsion is obtained in the form of particles, and the particle diameter 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 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. The decrease can also maintain the frost damage resistance of the coating film.

  The relationship between the Tg of the polymer (B) and the MFT of the emulsion is preferably (MFT of the emulsion) ≦ (Tg of the polymer (B) + 30 ° C.), and (MFT of the emulsion) ≦ (polymer (B ) Tg + 20 ° C.). 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. 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.

  According to the method for producing an emulsion of the present invention described above, blocking resistance and frost damage resistance are determined by defining the mass ratio and total amount of the anionic surfactant (I) and the nonionic surfactant (II). An emulsion for obtaining an aqueous coating material capable of forming a coating film excellent in water resistance, mud crack resistance and weather resistance can be produced.

[Water-based coating material]
The aqueous coating material of the present invention contains an emulsion having a different layer structure obtained by the method for producing an emulsion of the present invention.
The aqueous coating material of this invention forms solid content with the emulsion which is a main component, the said surfactant, an additive, etc., and is normally used in the state of 20-80 mass% of 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.

  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.

  The aqueous coating material of the present invention comprises one step of ethylenically unsaturated monomer (a) in the presence of a specific mass ratio and a total amount of anionic surfactant (I) and nonionic surfactant (II). Including emulsion obtained by emulsion polymerization to form polymer (A), and then adding ethylenically unsaturated monomer (b) and emulsion polymerization to form polymer (B) Therefore, a coating film excellent in blocking resistance, frost damage resistance, water resistance, mud crack resistance and weather resistance can be formed.

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.
Preparation of aqueous dispersion of polyorganosiloxane polymer (X), preparation of aqueous coating material for evaluation (white enamel paint, clear paint), measurement of physical properties of emulsion dispersion, and coating film obtained from aqueous coating material for evaluation The evaluation was performed according to the following method. In the following description, “parts” and “%” are all based on mass.

<Preparation of aqueous dispersion of polyorganosiloxane polymer (X)>
A premixed composition of 98 parts of a cyclic dimethylsiloxane oligomer 3 to 7-mer mixture, 2 parts of γ-methacryloxypropyltrimethoxysilane, 310 parts of water and 1 part of sodium dodecylbenzenesulfonate with a homomixer, pressure A silicon raw material pre-emulsion was obtained by forcibly emulsifying with a pressure of 200 kg / cm ² by a type homogenizer.
Next, 90 parts of water and 9 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 mixture was stirred for 4 hours while maintaining the internal temperature of the flask at 85 ° C. Said silicon raw material pre-emulsion was dripped. After completion of the dropwise addition, the polymerization was further allowed to proceed for 1 hour, followed by cooling and addition of dodecylbenzenesulfonic acid and an equimolar amount of sodium hydroxide to prepare an aqueous dispersion (SiEm) of polyorganosiloxane polymer (X). . The solid content was 18%.

<Production of water-based coating material for evaluation (white enamel paint)>
TYPEQUE CR-97 (Ishihara Sangyo Co., Ltd., chlorinated titanium oxide) 707 g, Adeka Coal-193 (Asahi Denka Kogyo Co., Ltd., pigment dispersant), 12 g, Surfynol DF-58 (Air Products Co., Ltd.) Antifoaming agent) 25 g and deionized water 256 g are mixed well, glass beads are added and pigment dispersion is performed for 30 minutes with a high-speed disperser, and then glass beads are filtered with a 100 mesh nylon jar, and an evaluation mill base (Solid content 71%) was obtained.
Next, when the MFT of the emulsion exceeded 10 ° C., CS-12 (manufactured by Chisso Co., Ltd., film-forming aid) was added as a film-forming aid to make the MFT 10 ° C. or less.
Next, 141 g of emulsion dispersion (based on a solid content of 42.5%), 56.3 g of the above-mentioned evaluation base, and 0.5 g of RHEOLATE 350 (RHEOX Co., Ltd., thickener) were added in this order. And deionized water was added to adjust the viscosity to about 30 seconds in a Ford Cup # 4. Thereafter, filtration was again performed using a 100 mesh nylon candy to obtain a white enamel paint for evaluation with PWC = 40%. “PWC” is the mass ratio of the pigment (solid content) in 100% of the paint (solid content).

<Preparation of aqueous coating material for evaluation (clear paint)>
When the MFT of the emulsion exceeded 10 ° C., CS-12 (manufactured by Chisso Co., Ltd., film-forming aid) was added as a film-forming aid to make the MFT 10 ° C. or lower.
Next, 0.5 g of RHEOLATE 350 (RHEOX Co., Ltd., thickener) and 0.5 g of Surfynol DF-58 (Air Products Co., Ltd., defoaming agent) are added to 100 g of the emulsion dispersion. The mixture was sufficiently stirred and adjusted by adding deionized water so that the viscosity was about 30 seconds in a Ford Cup # 4. Thereafter, filtration was performed using a 100 mesh nylon candy to obtain a clear paint for evaluation.

<Measurement of physical properties>
(1) Measurement of heating residue Measurement was performed in accordance with JIS K6828 5.1.

(2) Measurement of viscosity The measurement was carried out according to JIS K6828 5.4.

(3) Measurement of pH Measurement was carried out according to JIS K6828 5.3.

(4) Measurement of minimum film-forming temperature (MFT) Measurement was carried out in accordance with JIS K6828 5.11.

<Evaluation method>
(5) Evaluation of blocking resistance (high temperature drying) A white enamel paint for evaluation was applied to 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., a 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. Maintained. Next, after cooling to room temperature, the glass plate was turned upside down, and the gauze was slowly peeled off. The difficulty in peeling and the traces of the gauze were visually observed and evaluated according to the following criteria.
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: A part of the coating film was also peeled off when the gauze was peeled off, and the traces of the gauze remained clearly.

(6) Evaluation of blocking resistance (low temperature drying) The above (5) blocking resistance (high temperature drying) except that the temperature of forced drying for 5 minutes after coating a white enamel paint for evaluation on a glass plate is 50 ° C. Evaluation similar to the evaluation was performed, and evaluation was performed based on the same evaluation criteria.

(7) Evaluation of resistance to mud cracks A white enamel paint for evaluation was applied to a glass plate with an 8 mil applicator (length 100 mm × width 15 mm) and forcedly dried at 130 ° C. for 2 minutes. The presence or absence of “mad crack” was visually observed and evaluated according to the following criteria.
(Double-circle): A mud crack is hardly seen but the continuous coating film is made.
○: Some mud cracks are seen at the edge of the painted surface.
(Triangle | delta): Although a mud crack is seen, it is less than 50% with respect to the vertical direction of a coating surface.
X: A 50% or more mud crack is seen with respect to the vertical direction of the painted surface.

(8) Evaluation of frost damage resistance White enamel paint (PWC = 40%) using Dianal LX-1010 (manufactured by Mitsubishi Rayon Co., Ltd.) as a sealer was prepared.
On the plaster slag perlite plate (thickness 12 mm × length 150 mm × width 70 mm), the above sealer was spray-coated at room temperature so that the coating amount was 90 to 100 g / m ² (wet mass), and 5 ° Dried for minutes. Next, a white enamel paint for evaluation was spray-coated on the sealer layer at room temperature so that the coating amount was 90 to 100 g / m ² (wet mass), dried at 130 ° C. for 5 minutes, and the test plate Was made. The test plate was allowed to stand at room temperature for 1 day, and then the side and back surfaces of the test plate were sealed with a waterproof function using a solvent-based two-component curable acrylic resin. After one day, the frost damage resistance test was conducted with a freeze-thaw tester. The freeze-thaw test 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: No crack at 300 cycles.
○: There are cracks at 200 cycles or more and less than 300 cycles.
Δ: There are cracks at 100 cycles or more and less than 200 cycles.
X: There are cracks in less than 100 cycles.

(9) Evaluation of water resistance A clear coating for evaluation was applied to a glass plate with a 4 mil applicator (80 mm long × 80 mm wide) and forcedly dried at 130 ° C. for 5 minutes. Then it was allowed to cool to room temperature. Thereafter, the glass plate was immersed in warm water at 50 ° C. for 24 hours, and then the glass plate was pulled up and further left at room temperature for 24 hours to be dried. The appearance of the obtained coating film was visually observed and evaluated according to the following criteria.
(Double-circle): The whitening of a coating film was little and it became a completely transparent film immediately after raising.
◯: Some whitening of the coating film was observed, but after the pulling up, the original transparent coating film was obtained in about 2 to 3 hours.
(Triangle | delta): Whitening of the coating surface was recognized to some extent, it became a little cloudy even after 24 hours of drying, and barely became the original transparent coating film after 48 hours.
X: The painted surface was considerably whitened, and it remained whitened even after 24 hours of drying, and did not become the original transparent coating film until the end.

(10) Evaluation of weather resistance In the same manner as that used for evaluation of frost damage resistance, a test plate with side and back surfaces sealed is used, and after one day of sealing, a die plastic metal weather KU-R4-W type (Daipura Wintes The weather resistance test was carried out. At this time, the test cycle was 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 during irradiation Under the conditions of% RH / 96% RH at the time of condensation, the 60 ° gloss retention after 600 hours 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.

[Example 1]
In a flask equipped with a stirrer, a reflux condenser, a temperature controller, and a dropping pump, 103 parts of deionized water, 2.10 parts of Adeka Soap SR-1025 (manufactured by ADEKA, solid content 25%), Emulgen E- 1150-60S (manufactured by Kao Corporation, solid content 60%) 0.45 part, a mixture of radical polymerizable monomers which are constituents of the copolymer shown in “monomer (a)” in Table 1 Prepared. After raising the internal temperature of the flask to 50 ° C., an aqueous solution consisting of 0.15 parts of ammonium persulfate and 1 part of deionized water was added, and immediately thereafter, 0.05 part of sodium bisulfite and 1 part of deionized water. An aqueous solution was added. After confirming the exothermic peak, when the internal temperature reached 80 ° C., a mixture of radical polymerizable monomers that are constituents of the copolymer shown in “Monomer (b)” in Table 1, deionized water An internal temperature of 80 ° C. was obtained by preliminarily emulsifying and dispersing 25 parts, 1.88 parts of Adekalia soap SR-1025 (solid content 25%), and 0.38 parts of Emulgen E-1150-60S (solid content 60%). For 1.5 hours. After completion of the dropwise addition, the mixture was held at an internal temperature of 80 ° C. for 1.5 hours, then cooled to room temperature, and 0.84 part of 28% ammonia water was added to obtain an emulsion dispersion.
Using the obtained emulsion dispersion, 5 parts of film-forming aid CS-12 was added to 100 parts of the emulsion to produce an aqueous coating material for evaluation (white enamel paint and clear paint), and each evaluation was performed. . The results are shown in Table 2.

[Reference Example 2]
Initially, the amount of Adeka Soap SR-1025 charged to the flask was 3.2 parts, the amount of Emulgen E-1150-60S was 0.33 parts, and the pre-emulsion liquid of “monomer (b)” was prepared. An emulsion dispersion was obtained in the same manner as in Example 1, except that the amount of Adekaria soap SR-1025 was 1.6 parts and the amount of Emulgen E-1150-60S was 0.17 parts.
Using the obtained emulsion dispersion, 5 parts of film-forming aid CS-12 was added to 100 parts of the emulsion to produce an aqueous coating material for evaluation (white enamel paint and clear paint), and each evaluation was performed. . The results are shown in Table 2.

[Example 3]
Except that the amount of Adekaria soap SR-1025 charged at the time of preparation of the pre-emulsion liquid of “monomer (b)” was 3.48 parts and that of Emulgen E-1150-60S was 0.75 parts An emulsion dispersion was obtained in the same manner as in Example 1.
Using the obtained emulsion dispersion, 5 parts of film-forming aid CS-12 was added to 100 parts of the emulsion to produce an aqueous coating material for evaluation (white enamel paint and clear paint), and each evaluation was performed. . The results are shown in Table 2.

[Reference Example 4]
An emulsion dispersion was obtained in the same manner as in Example 1 except that the “monomer (a)” having the composition shown in Table 1 was used.
Using the obtained emulsion dispersion, 5 parts of film-forming aid CS-12 was added to 100 parts of the emulsion to produce an aqueous coating material for evaluation (white enamel paint and clear paint), and each evaluation was performed. . The results are shown in Table 2.

[Example 5]
An emulsion dispersion was obtained in the same manner as in Example 1 except that the “monomer (b)” having the composition shown in Table 1 was used and the amount of 28% ammonia water added was 1.68 parts. .
Using the obtained emulsion dispersion, 5 parts of film-forming aid CS-12 was added to 100 parts of the emulsion to produce an aqueous coating material for evaluation (white enamel paint and clear paint), and each evaluation was performed. . The results are shown in Table 2.

[Example 6]
The emulsion dispersion was prepared in the same manner as in Example 1 except that 11.1 parts (solid content: 2 parts) of an aqueous dispersion (SiEm) of the polyorganosiloxane polymer (X) was added to the flask initially charged. Obtained.
Using the obtained emulsion dispersion, 5 parts of film-forming aid CS-12 was added to 100 parts of the emulsion to produce an aqueous coating material for evaluation (white enamel paint and clear paint), and each evaluation was performed. . The results are shown in Table 2.

[Example 7]
Using "monomer (a)" and "monomer (b)" having the composition shown in Table 1, after adding 28% aqueous ammonia, 0.7 part of adipic dihydrazide and 1.5 parts of deionized water An emulsion dispersion was obtained in the same manner as in Example 1, except that an aqueous solution consisting of
Using the obtained emulsion dispersion, 5 parts of film-forming aid CS-12 was added to 100 parts of the emulsion to produce an aqueous coating material for evaluation (white enamel paint and clear paint), and each evaluation was performed. . The results are shown in Table 2.

[Comparative Example 1]
Except that the amount of Adekaria soap SR-1025 charged at the time of preparation of the pre-emulsion liquid of “monomer (b)” was 4.88 parts and that of Emulgen E-1150-60S was 0.15 parts. An emulsion dispersion was obtained in the same manner as in Example 1.
Using the obtained emulsion dispersion, 5 parts of film-forming aid CS-12 was added to 100 parts of the emulsion to produce an aqueous coating material for evaluation (white enamel paint and clear paint), and each evaluation was performed. . The results are shown in Table 3.

[Comparative Example 2]
Except that the amount of Adekaria soap SR-1025 charged at the time of preparing the pre-emulsion liquid of “monomer (b)” was 5.88 parts and the amount of Emulgen E-1150-60S was 1.22 parts. An emulsion dispersion was obtained in the same manner as in Example 1.
Using the obtained emulsion dispersion, 5 parts of film-forming aid CS-12 was added to 100 parts of the emulsion to produce an aqueous coating material for evaluation (white enamel paint and clear paint), and each evaluation was performed. . The results are shown in Table 3.

[Comparative Example 3]
In a flask equipped with a stirrer, a reflux condenser, a temperature controller, and a dropping pump, 93 parts of deionized water and a radical polymerizable monomer that is a constituent of the copolymer shown in “Monomer (a)” in Table 3 A pre-emulsified dispersion of 35 parts of deionized water, 5.6 parts of Adeka Soap SR-1025 (solid content 25%) and 1.2 parts of Emulgen E-1150-60S (solid content 60%) 40% of the emulsion was charged. After raising the internal temperature of the flask to 50 ° C., an aqueous solution consisting of 0.15 parts of ammonium persulfate and 1 part of deionized water was added, and immediately thereafter, 0.05 part of sodium bisulfite and 1 part of deionized water. An aqueous solution was added. After confirming the exothermic peak, when the internal temperature reached 80 ° C., the remaining pre-emulsion liquid was added dropwise at an internal temperature of 80 ° C. over 1.5 hours. After completion of the dropwise addition, the mixture was held at an internal temperature of 80 ° C. for 1.5 hours, then cooled to room temperature, and 0.84 part of 28% ammonia water was added to obtain an emulsion dispersion.
Using the obtained dispersion of the emulsion, 10 parts of a film-forming auxiliary CS-12 was added to 100 parts of the emulsion to produce an aqueous coating material for evaluation (white enamel paint and clear paint), and each evaluation was performed. . The results are shown in Table 3.

In addition, the symbol in Tables 1-3 is as follows. The Tg of the monomer homopolymer and the SP value of the monomer are shown in parentheses.
MMA: methyl methacrylate [Tg: 105 ° C., SP value: 20.15 (J / cm ³ ) ^1/2 ],
2-HEMA: 2-hydroxyethyl methacrylate [Tg: 55 ° C., SP value: 24.98 (J / cm ³ ) ^1/2 ],
GMA: Glycidyl methacrylate [Tg: 46 ° C., SP value: 20.77 (J / cm ³ ) ^1/2 ],
TAC: triallyl cyanurate [Tg: unknown, SP value: 20 to 30 (J / cm ³ ) ^1/2 ],
CHMA: cyclohexyl methacrylate [Tg: 83 ° C., SP value: 19.78 (J / cm ³ ) ^1/2 ],
n-BMA: n-butyl methacrylate [Tg: 20 ° C., SP value: 19.12 (J / cm ³ ) ^1/2 ],
2-EHA: 2-ethylhexyl acrylate [Tg: −55 ° C., SP value: 18.83 (J / cm ³ ) ^1/2 ],
KBM-502: γ-methacryloyloxypropyldimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) [Tg: unknown, SP value: less than 20 (J / cm ³ ) ^1/2 ],
AA: acrylic acid [Tg: 106 ° C., SP value: 25.70 (J / cm ³ ) ^1/2 ],
DAAM: diacetone acrylamide [Tg: 65 ° C., SP value: 20 to 30 (J / cm ³ ) ^1/2 ],
ADEKA rear soap SR-1025: reactive anionic surfactant (solid content 25%) (trade name, manufactured by ADEKA Corporation)),
Emulgen E-1150-60S: Nonionic surfactant (solid content 60%) (trade name, manufactured by Kao Corporation))
ADH: adipic acid dihydrazide.

As is clear from the results in Tables 1 and 2, the coating film formed from the paint containing the emulsion obtained in each example has a blocking resistance, a mud crack resistance, a frost damage resistance, a water resistance, and a weather resistance. It had all the performance.
On the other hand, as is clear from the results in Table 3, the weight ratio of the anionic surfactant (I) to the nonionic surfactant (II) was 1.75: 0.36. The coating film formed from the paint containing the obtained emulsion was inferior in mud crack resistance.
The total amount of the anionic surfactant (I) and the nonionic surfactant (II) is 100 parts by mass in total of the ethylenically unsaturated monomer (a) and the ethylenically unsaturated monomer (b). On the other hand, the coating film formed from the coating material containing the emulsion obtained in Comparative Example 2 having 3 parts by mass was remarkably inferior in mud crack resistance. Moreover, it was inferior also in water resistance or a weather resistance.
After forming the polymer (A), the coating film formed from the paint containing the emulsion obtained in Comparative Example 3 that did not form the polymer (B) has anti-blocking property (particularly in the case of low temperature drying). It was inferior in mud crack resistance and frost damage resistance.
As mentioned above, the coating film formed from the coating material containing the emulsion obtained in each comparative example was inferior in the physical property balance of blocking resistance, mud crack resistance, frost damage resistance, water resistance, and weather resistance.

  Thus, according to the present invention, an emulsion having a heterogeneous structure is produced by emulsion polymerization of a specific surfactant at a specific ratio and a specific part by mass, so that blocking resistance, frost damage resistance, water resistance The aqueous coating material which forms the coating film excellent in the mud crack resistance and the weather resistance can be provided.

  The aqueous coating material containing an emulsion obtained by the method for producing an emulsion of the present invention is extremely useful industrially, for example, metal, glass, porcelain tile, concrete, asphalt, slate, wood, ALC, siding board, waterproof rubber. It can be used for surface finishing of various materials such as materials, extruded plates, plastics and the like, and is extremely useful as an aqueous coating material mainly used for protecting housings of buildings and civil engineering structures.

Claims (4)

In the presence of the anionic surfactant (I) and the nonionic surfactant (II), the ethylenically unsaturated monomer (a) is emulsion-polymerized in one or more stages to form a polymer (A), Thereafter, an ethylenically unsaturated monomer (b) having a composition different from that of the ethylenically unsaturated monomer (a) is added, and the emulsion is produced by emulsion polymerization to form a polymer (B). ,
The mass ratio of the anionic surfactant (I) to the nonionic surfactant (II) is (I) :( II) = 3: 1 to 1: 4, and the anionic surfactant (I ) And the nonionic surfactant (II) in a total mass of 100 parts by mass of the ethylenically unsaturated monomer (a) and the ethylenically unsaturated monomer (b) used in the emulsion polymerization. 0.5 to 2.5 parts by mass,
The ethylenically unsaturated monomer (a) is 75 to 100% by mass of the ethylenically unsaturated monomer (c) having a solubility parameter (SP value) of 20 to 30 (J / cm ³ ) ^1/2. Including
The manufacturing method of the emulsion whose glass transition temperature (Tg) of the said polymer (A) is 70-110 degreeC.   The ethylenically unsaturated monomer (c) contains at least methyl methacrylate, and the content of the methyl methacrylate is the ethylenically unsaturated monomer (a) and the ethylenically unsaturated monomer used for the emulsion polymerization. The method for producing an emulsion according to claim 1, which is 30% by mass or more based on the total mass with (b).   The total amount of the anionic surfactant (I) and the nonionic surfactant (II) is an ethylenically unsaturated monomer (a) and an ethylenically unsaturated monomer (b) used in the emulsion polymerization. The manufacturing method of the emulsion of Claim 1 or 2 which is 0.5-1.5 mass parts with respect to 100 mass parts of total mass of.   The aqueous coating material containing the emulsion obtained by the manufacturing method of the emulsion in any one of Claims 1-3.