JP2001098003A - Method for preparation of aqueous emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing an aqueous emulsion so that a coating film formed from the emulsion has excellent stain resistance and water resistance. SOLUTION: A mixed soln. of (a) a hydrolyzable silane compd. and (b) a radically-polymerizable monomer is emulsified into a aqueous medium in the presence of a surfactant to form a aqueous monomeric emulsion with a dispersoid having an average particle size of <=1 μm. The an aqueous emulsion can be prepd. by adding the above-described aqueous monomeric emulsion to a heated aqueous medium dropwise in the presence of a water-soluble radical polymerization initiator to polymerize the monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an aqueous emulsion containing a hydrolyzable silane compound, and a coating film formed from the aqueous emulsion obtained by the present invention is provided with water resistance and stain resistance. And can be awarded in technical fields such as adhesion, sealing materials, paints and coating agents.

[0002]

2. Description of the Related Art Conventionally, paints for outdoor painting have an aesthetic appearance due to contaminants caused by automobile exhaust gas, sand dust, iron powder, etc., being deposited on the surface of the coating film and rain streak-like stains. The problem of spoilage, that is, the problem of stain resistance, has become apparent, and a material having excellent stain resistance has been required. On the other hand, acrylic emulsion-based paints based on acrylic polymers have been used for various applications, and are also used as paints for outdoor painting. However, acrylic emulsion-based paints have a problem that they are poor in stain resistance due to lower coating film hardness as compared with organic solvent-based paints because they are emulsion-type paints. .

As a measure for improving the stain resistance of an organic solvent type paint, a method of blending an alkyl silicate or a partial hydrolyzate thereof with the paint has been proposed (Japanese Patent Laid-Open No. Hei 6 (1994)).
-248237). This imparts hydrophilicity and oil repellency in water to the coating film surface, and when the coating film surface is wet by rainwater,
The dirt is removed by a so-called rolling-up mechanism in which contaminants on the surface of the coating film flow down together with rainwater or the like. However, in emulsion-based paints, it is difficult to stably maintain hydrolyzable substances such as alkyl silicates in water, and it has been said that it is difficult to improve the stain resistance by the above method. .

[0004]

SUMMARY OF THE INVENTION The present inventors have attempted to copolymerize a radically polymerizable alkoxysilane with another vinyl monomer using an ionic surfactant having a radically polymerizable double bond. Thus, it has been found that a curable emulsion excellent in both storage stability and coating film properties such as stain resistance can be obtained (JP-A-8-217807). Furthermore, the present inventors have studied to further improve the stain resistance of the obtained coating film, and after mixing a hydrolyzable silane compound with a monomer to form an aqueous dispersion, polymerization is carried out. It has been found that the resulting coating film has excellent stain resistance (Japanese Patent Application No. 10-216510). However,
Although these aqueous emulsions are excellent in storage stability and stain resistance of the coating film, the physical properties of the coating film are under severe conditions, especially in terms of warm water resistance, probably because the particle size of the obtained emulsion is slightly large. It was not enough. The present inventors have conducted intensive studies to find a method for producing a water-based emulsion in which a coating film of the obtained emulsion is excellent in stain resistance and further excellent in water resistance.

[0005]

Means for Solving the Problems The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, have reduced the particle size of the aqueous emulsion dispersion to 1 μm or less, and obtained a water-soluble polymerization initiator. It has been found that by using this, the particles of the emulsion finally obtained become finer and a coating film excellent not only in stain resistance but also in water resistance can be obtained, and the present invention has been completed. Hereinafter, the present invention will be described in detail. In this specification, an acryloyl group or a methacryloyl group is referred to as a (meth) acryloyl group, acrylic acid or methacrylic acid is referred to as (meth) acrylic acid, and acrylate or methacrylate is referred to as (meth) acrylate.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION 1. (a) Hydrolyzable silane compound The hydrolyzable silane compound in the present invention has a radical polymerizable group (hereinafter referred to as a polymerizable silane compound) and a radically polymerizable silane compound. There are some which do not (hereinafter referred to as non-polymerizable silane compounds). Hereinafter, each silane compound will be described.

1-1. Polymerizable silane compound Examples of the polymerizable silane compound include compounds represented by the following general formula (1).

[0008]

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[In the formula (1), R ¹ is a monovalent hydrocarbon group selected from an alkyl group, an aryl group and an aralkyl group having 1 to 10 carbon atoms, R ² is a radical polymerizable group, X is an alkoxy group or A halogen atom, a is an integer from 0 to 2. When each of X and R ¹ bonded to Si is two or more, they may be the same group or different groups. ]

As the radical polymerizable group for R ² , an ethylenically unsaturated group is preferable, and a functional group having high radical polymerizability such as a (meth) acryloyl group, a styryl group, a vinyl ester group and a vinyl ether group is more preferable. In X, the alkoxy group includes a methoxy group, an ethoxy group,
A propoxy group, a butoxy group, a pentanoxy group and a hexanoxy group;
1, Br and I. From the balance between reactivity and stability, X is preferably an alkoxy group having 4 or less carbon atoms.

In the present invention, the polymerizable silane compound is preferably a radical polymerizable monomer having an alkoxysilyl group, and specific examples thereof include vinyltrimethoxysilane, vinylmethyldimethoxysilane, and γ-methacryloxypropyltrimethylsilane. Methoxysilane, γ-methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, vinyltripropoxysilane, vinylmethyldimethoxysilane Propoxysilane, γ
Methacryloxypropyltripropoxysilane and γ
-Methacryloxypropylmethyldipropoxysilane and the like. Two or more polymerizable silane compounds may be used in combination.

1-2. Non-polymerizable silane compound As the non-polymerizable silane compound, a monomer, dimer, trimer or oligomer of the compound represented by the following general formula (2) is preferable.

[0013]

Embedded image R ³ _n —Si— (R ⁴ ) _4-n ... (2)

[In the formula (2), R ³ is a stable hydrophobic group, and R ⁴ is a hydrolyzable group. n is an integer of 0, 1 or 2. ]

[0015] n is preferably 0 or 1.
Examples of the stable hydrophobic group for R ³ include an alkyl group,
And hydrocarbon-based substituents such as a phenyl group. R ⁴
Examples of the hydrolyzable group include an alkoxy group such as a methoxy group and an ethoxy group, a hydroxyl group, a halogen atom, an acetoxy group, a carboxyl group, and an isocyanate group. In the present invention, an alkoxy group is preferable from the viewpoint of storage stability and ease of handling. Note that R ³ and R ⁴
May be the same or different when there are a plurality.

Preferred specific examples of the non-polymerizable silane compound include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane,
Methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, cyclohexyltrimethoxysilane, benzyltrimethoxysilane, phenyl Examples include trimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, octyltrimethoxysilane, and octyltriisopropoxysilane. Alternatively, there are dimers, trimers and other oligomers of these compounds, and mixtures thereof. In the present invention, among these compounds, tetraalkoxysilane and trialkoxysilane are preferable. Two or more non-polymerizable silane compounds can be used in combination.

As the component (a), a mixture of a polymerizable silane compound and a non-polymerizable silane compound at an arbitrary ratio can be used. In order to obtain a coating film having more excellent weather resistance,
It is preferable to use the component (a) containing 10 to 100% by weight of the polymerizable silane compound.

2. (b) Radical polymerizable monomer As the component (b) in the present invention, various compounds having radical polymerizability can be used, and methyl (meth) acrylate, (meth) methyl Ethyl acrylate, (meth)
N-butyl acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)
Alkyl (meth) acrylates such as lauryl acrylate, stearyl (meth) acrylate, (meth) acrylic acid 2
(Meth) acrylates such as -hydroxyethyl, 2-hydroxypropyl (meth) acrylate, perfluoroalkyl (meth) acrylate, glycidyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate; Examples include vinyl acetate, vinyl propionate, styrene and α-methylstyrene.

In the present invention, as the component (b), a monomer having a radically polymerizable functional group at one end of a molecule having two or more identical structural units, a so-called macromonomer, is preferably used in combination. Examples of the macromonomer include a polyester macromonomer, a polyalkylene oxide macromonomer, a poly (meth) acrylate macromonomer, and a polysiloxane macromonomer. By using macromonomer together, 1
A fine aqueous emulsified dispersion of μm or less can be made stable for a long time. The amount of the macromonomer used is preferably 5 to 50% by weight in the component (b).

The following are specific examples of the polyester macromonomer. Polyester macromonomer manufactured by Daicel Chemical Industries, Ltd .: • Plaxel FM3 (containing a methacryloyl group and a degree of condensation of 3)
・ Placcel FA3 (containing acryloyl group, condensation degree 3) ・ Placcel FM6 (containing methacryloyl group, condensation degree 6)
・ Praccel FA6 (containing acryloyl group, condensation degree 6) ・ Placcel FM8 (containing methacryloyl group, condensation degree 8)
) Placcel FA8 (containing an acryloyl group and having a degree of condensation of 8).

Specific examples of the polyalkylene oxide macromonomer include the following. Polyalkylene oxide macromonomer manufactured by NOF Corporation: Blenmer PP-1000 (polypropylene oxide having a degree of condensation of 5 to 6 with a methacryloyl group bonded to one end) Blenmer PP-500 (a methacryloyl group bonded to one end Blenmer PP-800 (polypropylene oxide having a degree of condensation of 12 at one end with a methacryloyl group bonded) Blenmer PE-200 (polyethylene oxide having a degree of condensation of 4 to 5 with a methacryloyl group bonded at one end) Blenmer PE-350 (polyethylene oxide having a degree of condensation of 7 to 9 and a methacryloyl group bonded to one end).

A preferred vinyl polymer which is a structural unit of a macromonomer of poly (meth) acrylate is
Alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate and n-butyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, It is a homopolymer or a copolymer of acrylonitrile, vinyl acetate or styrene. The following are specific examples of the macromonomer of poly (meth) acrylate. These all have a methacryloyl group as a radical polymerizable group. Toagosei Co., Ltd. macromonomer: AS-6 (polystyrene, number average molecular weight; 6000) AN-6 [copoly (styrene / acrylonitrile),
AA-6 (polymethyl methacrylate, number average molecular weight; 6000) AA714S [copoly (methyl methacrylate / 2-
Hydroxyethyl methacrylate), number average molecular weight; 7
000] AX707S [copoly (butyl methacrylate / 2-
Hydroxyethyl methacrylate), number average molecular weight; 7
000]

The following are specific examples of the polysiloxane macromonomer. These all have a methacryloyl group as a radical polymerizable group. Macro monomers manufactured by Toagosei Co., Ltd .: AK5 (polysiloxane, number average molecular weight; 5000) AK30 (polysiloxane, number average molecular weight; 30,000)
0) Macro monomer manufactured by Chisso Corporation: FM0725 (polysiloxane, number average molecular weight; 1)
0000)

The preferred proportions of the components (a) and (b) are as follows:
0.5-50% by weight of component (a) and 99.5-50 of component (b)
%, More preferably 3 to 30% by weight of the component (a).
And 97 to 70% by weight of the component (b). If the proportion of the component (a) is less than 0.5% by weight, the coating formed from the resulting aqueous emulsion may have insufficient stain resistance, whereas if it exceeds 50% by weight, the emulsion may not be stable. Performance may be reduced.

3. Surfactant In the present invention, various surfactants can be used, and preferred surfactants are the above-mentioned polymerizable silane compounds and / or
(b) Copolymerizable with the component, is an ionic compound having a radical polymerizable group, more preferably, the following general formula
It is a radically polymerizable surfactant represented by (3).

[0026]

Embedded image Z- (AO) n-Y (3)

[In the formula (3), Z is a structural unit having a radical polymerizable double bond, AO is an oxyalkylene group,
n represents an integer of 2 or more, and Y represents an ion dissociable group. Preferred Z in the formula (3) is a structural unit comprising a radical group and a hydrophobic group such as an aromatic hydrocarbon group, an alkyl-substituted aromatic hydrocarbon group, a higher alkyl group or an alicyclic hydrocarbon group. The radical polymerizable double bond in Z is preferably a (meth) allyl group, a propenyl group, a butenyl group, or the like. The unit A in the group (AO) n, that is, the alkylene group, is preferably an ethylene group or a propylene group. Further, as a specific example of Y, -SO ₃ N
_{a, -SO 3 NH 4, -COONa} , -COONH 4, -
PO ₃ Na ₂ and PO ₃ (NH ₄ ) ₂ .

Specific examples of preferred surfactants include
For example, compounds represented by the following formulas (4), (5) and (6)
Can be R in formulas (4) and (5)^FiveAnd R⁶As the carbon number
6-18 linear or branched alkyl groups are preferred. formula
R in (6)⁷Is preferably a hydrogen atom or a methyl group;⁸When
Thus, an alkyl group having 8 to 24 carbon atoms is preferable. formula
A of (4)-(6)¹, A^TwoAnd A ^ThreeRepresents an alkylene group;
In any of the compounds, n is an integer of 2 or more. formula
Y in (4) to (6)¹, Y^TwoAnd Y^ThreeIs as described above.
You. The preferred amounts of the surfactant used are (a) component and (b) component.
0.5 to 20 parts by weight per 100 parts by weight of total
And more preferably 1 to 5 parts by weight.

[0029]

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[0030]

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[0031]

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4. Water-Soluble Radical Polymerization Initiator In the present invention, a polymerizable silane compound and / or component (b) are polymerized using a water-soluble radical polymerization initiator (hereinafter, referred to as a water-soluble initiator). Examples of the water-soluble initiator include hydrogen peroxide, diisopropyl peroxydicarbonate,
Organic peroxides such as tert-butyl peroxypivalate and t-butyl hydroperoxide; inorganic peroxides such as ammonium persulfate and potassium persulfate; and azobisamidinopropane hydrochloride, 2,2′-azobis [2 -(5-methyl-2-imidazolin-2-yl)
Azo compounds such as [propane] dihydrochloride and 2′2-azobis (2-methylpropionamide) dihydrochloride. A redox initiator may be used. In this case, a reducing agent such as sodium bisulfite, sodium sulfite, and ascorbic acid is used together with the peroxide.

The amount of the water-soluble initiator to be used may be appropriately set according to the raw materials used and the purpose, but is preferably based on 100 parts by weight of the total amount of the component (b) or the polymerizable silane compound and the component (b). It is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight.

5. Method for Producing Aqueous Emulsion In the present invention, a mixed solution comprising the components (a) and (b) is emulsified and dispersed in an aqueous medium in the presence of a surfactant, and the average particle size of the mixed solution is determined. Aqueous emulsion for producing an aqueous emulsified dispersion having a particle size of 1 μm or less, then dropping the aqueous emulsified dispersion in a heated aqueous medium in the presence of a water-soluble initiator to polymerize the radical polymerizable monomer It is a manufacturing method of.

As a method of emulsifying and dispersing a mixed solution comprising the components (a) and (b) in an aqueous medium, a mixed solution comprising the components (a), (b) and a surfactant is used. A method of adding the mixture to the medium with stirring may be used. Examples of the stirring method in this case include a commonly used mixer, that is, a method of stirring with a rotary homomixer, and the like, in that a fine aqueous emulsified dispersion intended for the present invention is obtained. It is preferable to use a dispersing device having high shear energy, such as a high-pressure emulsifying disperser or a turbine type mixer generally called a homogenizer. In the present invention,
The average particle size of the dispersoid in the aqueous emulsified dispersion must be 1 μm or less, preferably 0.5 μm or less, and more preferably 0.2 μm or less. When the average particle size of the dispersoid exceeds 1 μm, the component (a) is easily decomposed during polymerization, and an insoluble suspended matter (grid) is easily generated during polymerization. In addition, the average particle diameter in the present invention means a volume average particle diameter measured by a laser diffraction / scattering method.

The preferred ratio of the mixed solution to the aqueous medium is 20 to 150 parts by weight of the aqueous medium per 100 parts by weight of the mixed solution.

In the present invention, the pH of the aqueous medium is
It is preferable to add an appropriate amount of a buffer. By adding a pH buffer to maintain the pH in the neutral region, hydrolysis of the component (a) in the aqueous medium is suppressed. Suitable amounts of pH buffer are in the range from 0.01 to 5% by weight, based on the aqueous medium. Examples of the pH buffer include sodium hydrogencarbonate, potassium hydrogencarbonate, monosodium phosphate, monopotassium phosphate, disodium phosphate, trisodium phosphate, sodium acetate, ammonium acetate, sodium formate, and the like. Sodium bicarbonate. Two or more kinds can be used in combination. For example, by using sodium hydrogen carbonate and monosodium phosphate in combination, the pH of the aqueous medium can be maintained at around 7.5. A weak alkali compound such as ammonia, monoethylamine, triethylamine and ethanolamine may be used as a pH adjuster together with the pH buffer as required.

Next, the aqueous emulsified dispersion obtained above is
The polymerizable silane compound and / or component (b) are polymerized by dropping into a heated aqueous medium in the presence of a water-soluble initiator. Specifically, the aqueous emulsified dispersion and the water-soluble initiator obtained as described above are dropped into a stirred reactor, which is charged with an aqueous medium and heated to a decomposition temperature of the water-soluble initiator or higher. The preferred initial charge of the aqueous medium to the reactor is 1 to 100 parts by weight of the aqueous emulsified dispersion dropped into the reactor.
It is about 0 to 50 parts by weight. It is preferable that the aqueous emulsified dispersion is gradually dropped into the reactor from a dropping funnel. As a method of charging the water-soluble initiator, a method of mixing and dissolving in an aqueous emulsified dispersion, a method of dissolving in an aqueous medium previously charged in advance, and simultaneously with continuously dropping the aqueous emulsified dispersion, A method of continuously supplying a radical polymerization initiator, and the like, and a method of mixing and dissolving in a water-based emulsified dispersion are preferable. The polymerization temperature may be appropriately selected depending on the water-soluble initiator to be used, but is usually 40 to 100 ° C.
The degree is preferred.

In the present invention, after a mixed solution comprising the components (a) and (b) is converted into an aqueous emulsion having a fine particle diameter in an aqueous medium, emulsion polymerization is carried out. The polymerization method is generally called a mini-emulsion polymerization method, and according to the polymerization method, compared with a general emulsion polymerization method, the frequency with which the monomer is mixed with water is small, and the hydrolyzable silane is used. Hydrolysis of the compound is unlikely to occur.
Compared to the microsuspension polymerization method described in No. 0, the particle size of the finally obtained emulsion is reduced, so that a coating film having excellent film formability and more excellent water resistance can be obtained. .

6. Use The aqueous emulsion obtained according to the present invention is suitable as a coating agent, and may be glass, calcium silicate, slate,
It is applicable to substrates such as metal, wood and plastic. More specifically, paints for building materials, paints for acid rain resistance,
It is used as an antifouling paint, a water repellent for inorganic building materials, a moisture-proof coating agent for electric and electronic parts, a back coat agent for magnetic tapes and a hardening finish agent for fibers, a water repellent agent and various sealing agents. A catalyst such as isopropyl triisostearoyl titanate, isopropyl tri (dioctyl pyrophosphate) titanate, tin dioctylate, dibutyltin dilaurate, dibutyltin malate or paratoluenesulfonic acid is blended into the emulsion to quickly cure the coating. May be.

[0041]

The present invention will now be described more specifically with reference to examples and comparative examples. In addition, “parts” representing the component amounts in each example all mean “parts by weight”. In the following, the average particle diameter is a value measured by a laser diffraction / scattering method. Further, the water-soluble initiator V50 used in the examples is
A product of Wako Pure Chemical Industries, Ltd.
-Methylpropionamide) dihydrochloride. Aqualon HS20, a radical polymerizable surfactant,
A product of Daiichi Kogyo Seiyaku Co., Ltd., whose chemical formula is the compound of the following formula (7) (provided that the degree of condensation n of the polyoxyethylene group is 20). Praxel FM8 is a product of Daicel Chemical Industries, Ltd. and is a compound represented by the following formula (8).

[0042]

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[0043]

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Example 1 1) Production process of aqueous emulsion dispersion The components (a) and (b), the radically polymerizable surfactant, the water-soluble initiator, the pH buffer and the water shown in Table 1 After mixing by the mixing amount shown in 1 and stirring and emulsifying and dispersing with a homomixer, the mixture was further stirred with a high-pressure homogenizer (manufactured by APV Gaulin) to produce an aqueous emulsified dispersion having a fine particle diameter. The average particle size of the obtained aqueous emulsified dispersion was about 0.1 μm.

[0045]

[Table 1]

2) Polymerization Step A flask equipped with a stirrer, a thermometer, and a cooler was charged with 70 parts of deionized water as an aqueous medium, the liquid temperature was raised to 85 ° C., and then the above-mentioned aqueous emulsion dispersion was stirred. The body was dropped over 3 hours. After completion of the dropping, the temperature of the internal solution was raised to 90 ° C.
The time was maintained to complete the polymerization. No liquid separation and blocking occurred during the polymerization, and the polymerization was carried out stably. The average particle size of the obtained aqueous emulsion was 0.06 μm.

3) Preparation of Composition The solid content of the obtained aqueous emulsion was 100 parts
An aqueous composition was prepared by blending 10 parts of tripropylene glycol-n-butyl ether (hereinafter abbreviated as TPNB).

4) Evaluation (1) Evaluation of hot water resistance The obtained aqueous composition was applied to a slate plate, dried at room temperature for 2 weeks, immersed in hot water of 80 ° C. for 3 days, and the state of the coating film was observed. did. ○: No change, △: Slight whitening, ×: Complete whitening and blistering (2) Evaluation of stain resistance White fluorine-based paint (Froncoat 900, Kawakami Paint Co., Ltd.) on a 0.6 mm thick aluminum plate The resulting aqueous composition was applied using a bar coater (dry film thickness: about 30 μm) and dried at room temperature for one week. The obtained coating film was subjected to an exposure test at an angle of 45 ° for 6 months in an industrial zone in the southern part of Nagoya City, and Δ, which is a change in L value before and after the test, was obtained.
L was measured. The smaller the absolute value of the ΔL value, the better the stain resistance.

Example 2 Same as Example 1 except that in the production process of the aqueous emulsion dispersion of Example 1, 10 parts of tetraethoxysilane was changed to 20 parts and 30 parts of n-butyl methacrylate was changed to 10 parts. A water-based emulsified dispersion was produced by the method described in The average particle size of the obtained dispersion was about 0.1 μm. Using the obtained aqueous emulsified dispersion, an aqueous emulsion was produced in the same manner as in Example 1. Using the obtained aqueous emulsion, an aqueous composition was produced in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 2 shows the results.

Comparative Example 1 In the production process of the aqueous emulsion dispersion of Example 1, 10 parts of tetraethoxysilane and n-butyl methacrylate 3
An aqueous emulsified dispersion was produced under the same conditions as in Example 1 except that the amount of 0 parts was changed to 40 parts of n-butyl methacrylate without using tetraethoxysilane. The average particle size of the obtained dispersion was about 0.1 μm. Using the obtained aqueous emulsified dispersion, an aqueous emulsion was produced in the same manner as in Example 1. Using the obtained aqueous emulsion, an aqueous composition was produced in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 2 shows the results.

Comparative Example 2 In the production process of the aqueous emulsion dispersion of Example 1, V50
Is not used, and instead, a water-insoluble polymerization initiator 2,
Except for using 2'-azobisisobutyronitrile,
An aqueous emulsified dispersion was produced under the same conditions as in Example 1.
The average particle size of the obtained dispersion was about 0.1 μm. Using the obtained aqueous emulsified dispersion, an aqueous emulsion was produced in the same manner as in Example 1. Using the obtained aqueous emulsion, an aqueous composition was produced in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 2 shows the results.

Comparative Example 3 An aqueous emulsified dispersion was prepared under the same conditions as in Example 1 except that in the production process of the aqueous emulsified dispersion of Example 1, the aqueous emulsified dispersion was not miniaturized with a high-pressure homogenizer. Manufactured. The average particle size of the obtained dispersion was about 3 μm. Using the obtained aqueous emulsified dispersion, an aqueous emulsion was produced in the same manner as in Example 1. Using the obtained aqueous emulsion, an aqueous composition was produced in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 2 shows the results.

[0053]

[Table 2]

Example 3 An aqueous emulsion dispersion was produced under the same conditions as in Example 1 except that the components shown in Table 3 were used in the production process of the aqueous emulsion dispersion of Example 1. The average particle size of the obtained dispersion was about 0.1 μm.

[0055]

[Table 3]

Using the obtained aqueous emulsion dispersion, an aqueous emulsion was produced in the same manner as in Example 1. Using the obtained aqueous emulsion, an aqueous composition was produced in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 4 shows the results.

Example 4 In the production process of the aqueous emulsion dispersion of Example 3, 20 parts of γ-methacryloxypropyltriethoxysilane
Parts, 10 parts of n-butyl methacrylate 20 parts,
An aqueous emulsified dispersion was produced under the same conditions as in Example 3 except that the above was changed to The average particle size of the obtained dispersion was about 0.1 μm. Using the obtained aqueous emulsified dispersion, an aqueous emulsion was produced in the same manner as in Example 1. Example 1 was prepared using the obtained aqueous emulsion.
An aqueous composition was produced in the same manner as in Example 1 and evaluated in the same manner as in Example 1. Table 4 shows the results.

Comparative Example 4 In the production process of the aqueous emulsion dispersion of Example 3, V50
Is not used, and instead, a water-insoluble polymerization initiator 2,
Except for using 2'-azobisisobutyronitrile,
An aqueous emulsified dispersion was produced under the same conditions as in Example 3.
The average particle size of the obtained dispersion was about 0.1 μm. Using the obtained aqueous emulsified dispersion, an aqueous emulsion was produced in the same manner as in Example 1. Using the obtained aqueous emulsion, an aqueous composition was produced in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 4 shows the results.

Comparative Example 5 An aqueous emulsified dispersion was prepared under the same conditions as in Example 3 except that in the production process of the aqueous emulsified dispersion of Example 3, the aqueous emulsified dispersion was not miniaturized with a high-pressure homogenizer. Manufactured. The average particle diameter of the obtained dispersion was about 4 μm. Using the obtained aqueous emulsified dispersion, an aqueous emulsion was produced in the same manner as in Example 1. Using the obtained aqueous emulsion, an aqueous composition was produced in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 4 shows the results.

[0060]

[Table 4]

[0061]

The water-based emulsion obtained according to the present invention has excellent water resistance as well as excellent stain resistance of the coating film, and is suitable for use in outdoor applications, such as paints, sealing agents and coating agents. It is extremely useful for various applications.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takehisa Yamamura 1 Toa Gosei Co., Ltd. Nagoya Research Laboratory, 1 Minami-ku, Nagoya-shi, Aichi F-term (reference) 4J011 KA02 KA03 KA04 KA05 KA06 KA15 KB08 KB14 KB29 4J100 AB02P AG02P AG04P AL03P AL04P AL05P AL08P AL08Q AL09P AL10P AP16Q BA31P BA77Q BB18P CA04 EA06 FA03 JA01

Claims (4)

[Claims] 1. A mixed solution comprising (a) a hydrolyzable silane compound and (b) a radical polymerizable monomer is emulsified and dispersed in an aqueous medium in the presence of a surfactant, and the average particle size of the dispersoid is obtained. Is 1
After preparing an aqueous emulsified dispersion of not more than μm, the aqueous emulsified dispersion is dropped into a heated aqueous medium in the presence of a water-soluble radical polymerization initiator to polymerize the radically polymerizable monomer. A method for producing an aqueous emulsion. 2. The method according to claim 1, wherein said mixed solution comprises 0.5 to 50% by weight of component (a) and 99.5 to 50% by weight of component (b). 3. The method for producing an aqueous emulsion according to claim 1, wherein the component (a) contains a radical polymerizable monomer having an alkoxysilyl group. (4) a surfactant represented by the general formula: Z- (AO) n-
Y (wherein, Z is a structural unit having a radical polymerizable double bond, AO is an oxyalkylene group, n is an integer of 2 or more, Y
The method according to any one of claims 1 to 3, wherein the surfactant is a radically polymerizable surfactant represented by the following formula: