JP2012214794A - Aqueous coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve dispersibility of a hydrophilic agent and pot life of a coating composition in an aqueous coating composition that contains a hydrophilic agent, specifically an aqueous coating composition that has synthetic resins, such as fluorine resin, as a coating component.SOLUTION: A two-component aqueous coating composition comprises: an aqueous coating component (I) containing the synthetic resin (A) having an acid value of 2.5 to 20 mg-KOH/g and a nonionic emulsifier (B); and a hydrophilic agent component (II) containing a water-dispersible organosilicate compound (C). The content of nonionic emulsifier (B) in the aqueous coating component (I) is 0.5 to 5 mass% per resin solid content.

Description

The present invention relates to a stable aqueous coating composition containing a hydrolyzable group-containing organometallic compound as a hydrophilizing agent and having a long pot life (pot life).

As paint compositions for coating, in addition to organic solvent-based paints, water-based paints using water as a dispersion medium are known from the viewpoint of consideration of the natural environment and improvement of the painting work environment. In addition, from the viewpoint of coating building materials, particularly roofing materials, and building materials such as outer walls, the water-based coating composition is required to have excellent antifouling property.

As one of the methods for improving the antifouling property, a hydrolyzable group-containing organometallic compound typified by an organosilicate compound such as alkoxysilane is blended as a hydrophilizing agent and hydrolyzed on the surface of the formed coating film. It has been performed to hydrolyze the functional group to make the coating film surface hydrophilic.

Water-based paint compositions containing a hydrophilizing agent are usually hydrophilized with a water-based paint component mainly composed of a synthetic resin as a binder resin and a hydrophilizing agent, and if necessary, a curing agent and a curing accelerator. It is prepared as a two-component water-based paint comprising an agent component, and both paint components are mixed and applied immediately before painting (Patent Documents 1 to 5). By the way, in order to form a uniform coating film, the water-based paint component and the hydrophilizing agent component can be mixed uniformly. Furthermore, in order to carry out the painting work with a margin, pot life after mixing (pot life) Is required to be long.

In these water-based paints containing the hydrophilizing agents described in Patent Documents 1 to 5, uniform dispersibility of the hydrophilizing agent such as organosilicate is a problem. Dispersibility is enhanced by adding a nonionic emulsifier to the mixture. Patent Documents 2, 3 and 4 attempt to obtain an effect of extending dispersibility and pot life by nonionic modification of organosilicate.

Japanese Patent Laid-Open No. 11-343462 JP 2002-129111 A JP 2002-129110 A JP 2007-153930 A JP 2008-013771 A

The object of the present invention is to improve the dispersibility of the hydrophilizing agent and the pot life of the coating composition in an aqueous coating composition containing a hydrophilizing agent, particularly an aqueous coating composition containing a synthetic resin such as a fluororesin. It is to provide a method.

As a result of intensive studies to solve such problems, the present inventors have used a synthetic resin having a specific acid value as a paint component, and additionally added a nonionic emulsifier to the paint component side to make it hydrophilic. The present inventors have found that the dispersibility of the agent and the pot life of the coating composition can be improved.

That is, the present invention
(I) A water-based paint component containing a synthetic resin (A) having an acid value of 2.5 to 20 mg KOH / g and a nonionic emulsifier (B), and (II) a hydrophilic containing a water-dispersible organosilicate compound (C) Containing an agent component,
The content of the nonionic emulsifier (B) in the aqueous coating component (I) is 0.5 to 5% by mass / resin solid content, and the present invention relates to a two-component aqueous coating composition.

The synthetic resin (A) is preferably a fluorine-acrylic composite resin, a fluororesin or an acrylic resin.

The HLB value of the nonionic emulsifier (B) is preferably 10-20.

The water-dispersible organosilicate compound (C) preferably has a nonionic modified alkyl group.

According to the aqueous coating composition of the present invention, the dispersibility of the hydrophilizing agent and the pot life of the coating composition can be improved.

The aqueous coating composition of the present invention is composed of a two-component system of an aqueous coating component (I) and a hydrophilizing component (II). The aqueous paint component (I) and the hydrophilizing component (II) are components that exist separately.

The aqueous paint component (I) contains a synthetic resin (A) having an acid value of 2.5 to 20 mg KOH / g and a nonionic emulsifier (B).

As a synthetic resin (A), 1 type (s) or 2 or more types, such as a fluorine-acrylic composite resin, a fluororesin, or an acrylic resin, are mention | raise | lifted.

Examples of the fluorine resin include a resin containing a fluoroolefin unit, a fluorine-containing urethane resin, and a fluorinated acrylic silicone resin. These fluororesins or acrylic-fluorine composite resins may be water-soluble or water-dispersible. In order to make it water-soluble or water-dispersible, a hydroxyl group, a carboxyl group, —SO ₂ F, SO ₃ M (M is a hydrogen atom, NH ₄ group, alkali metal or alkaline earth metal) or the like is introduced. preferable.

Further, the fluororesin or the acrylic-fluorine composite resin may be neutralized to enhance water solubility. The neutralizing agent used for neutralization is ammonia; organic amines such as diethylamine, ethylethanolamine, diethanolamine, monoethanolamine, monopropanolamine, isopropanolamine, ethylaminoethylamine, hydroxyethylamine, diethylenetriamine, triethylamine; Examples thereof include alkali metal hydroxides such as sodium and potassium hydroxide; alkali metal carbonates such as sodium hydrogen carbonate and sodium carbonate. Of these, ammonia, triethylamine, diethanolamine, sodium carbonate, and sodium hydrogen carbonate are preferable in terms of convenience in availability and stability of the emulsion, and ammonia and triethylamine are particularly advantageous in terms of easy handling.

The neutralizing agent is preferably used in the form of an aqueous solution, but may be used in the form of gas or solid content.

Specific fluororesins include polyvinylidene fluoride (PVdF), vinylidene fluoride (VdF) / tetrafluoroethylene (TFE) copolymer, VdF because of excellent weather resistance, solvent solubility, antifouling properties, and transparency. / TFE / hexafluoropropylene (HFP) copolymer, VdF / TFE / chlorotrifluoroethylene (CTFE) copolymer, polytetrafluoroethylene (PTFE), TFE / perfluoro (alkyl vinyl ether) (PAVE) copolymer Fluoroolefin polymers such as (PFA), ethylene (Et) / TFE copolymer (ETFE), polychlorotrifluoroethylene (PCTFE); copolymerized fluoroolefins such as TFE, CTFE, and HFP with functional group-containing monomers Functional group-containing fluoroolefin polymer Etc. Preferably, but not limited thereto.

In addition, as the fluorine-acrylic composite resin, a fluorine-containing polymer particle containing at least one kind of fluoroolefin unit is used as a seed particle, and an acrylic monomer containing at least one kind of acrylic acid ester or methacrylic acid ester monomer. Fluorine seed polymer particles obtained by using the body.

Fluoropolymer particles include non-fluorine monomers copolymerizable with fluoroolefins, such as olefins such as ethylene, propylene, and isobutylene; vinyl ether monomers, allyl ether monomers, vinyl ester monomers. A monomer may be copolymerized. Particularly preferred fluorine-containing polymers as seed particles are fluorine-containing copolymers containing VdF units from the viewpoint of good weather resistance and acrylic resin compatibility. Specifically, VdF / TFE / CTFE copolymer, VdF / TFE copolymer, VdF / TFE / HFP copolymer, VdF / CTFE copolymer, VdF / HFP copolymer, and the like.

An acrylic resin is also useful as the synthetic resin. The acrylic resin also needs to have an acid value of 2.5 to 20 mgKOH / g.

The synthetic resin used in the present invention needs to have an acid value of 2.5 to 20 mgKOH / g. When the acid value is less than 2.5 mgKOH / g, the pot life and film-forming property are inferior. On the other hand, when it exceeds 20 mgKOH / g, the water resistance and storage stability are inferior, and neither of the effects of the present invention is exhibited. The lower limit of the preferred acid value is 5 mgKOH / g from the viewpoint of good stability, and further 8 mgKOH / g from the viewpoint of good pot life. A preferred upper limit is 15 mg KOH / g from the viewpoint of good water resistance, and further 12 mg KOH / g from the viewpoint of good storage stability.

As a method for adjusting the acid value of the synthetic resin to 2.5 to 20 mgKOH / g, for example, the amount of carboxyl groups to be introduced may be adjusted.

In the present invention, as the resin for forming a coating film, other resins having an acid value outside the above range may be used in combination with a synthetic resin having an acid value of 2.5 to 20 mgKOH / g. Examples of other resins that can be used in combination include urethane resins, acrylic resins, and acrylic silicone resins. Of these, acrylic silicone resins are preferred from the viewpoint of good durability, weather resistance, transparency, and compatibility.

In the present invention, it is also an important feature that the water-based paint component (I) contains 0.5 to 5% by mass / resin solid content of a nonionic emulsifier.

If the concentration of the nonionic emulsifier in the aqueous paint component (I) is less than 0.5% by mass / resin solid content, the intended stability and compatibility cannot be obtained, and the effects of the present invention are not achieved. A preferable lower limit is 0.7% by mass / resin solid content from the viewpoint of good stability and compatibility. The upper limit is 5% by mass / resin solids from the viewpoint of good weather resistance, and preferably 2% by mass / resin solids from the viewpoint of good water resistance.

The nonionic emulsifier to be used is preferably a non-aromatic and non-reactive nonionic emulsifier, such as ethylene oxide-propylene oxide block copolymer, polyoxyalkylene branched decyl ether, polyoxyethylene tridecyl ether, Examples thereof include polyoxyalkylene alkyl ether emulsifiers such as polyoxyalkylene tridecyl ether, polyoxyethylene isodecyl ether, polyoxyalkylene lauryl ether, and polyoxyethylene polyoxypropylene glycol. Of these, polyoxyalkylene alkyl ether emulsifiers are preferred from the viewpoint of good dispersion stability.

The nonionic emulsifier used in the present invention is preferably a polyoxyethylene because, when an alkylene oxide-modified organosilicate compound is used as the organosilicate compound, the structure is more similar to the alkylene oxide chain that is modifying the organosilicate compound. A chain, and may further include a polypropylene oxide chain or a polybutylene oxide chain.

Examples of commercially available products include Emulgen 120 (polyoxyethylene lauryl ether, HLB: 15.3), Emulgen 123P (polyoxyethylene 23 lauryl ether, HLB: 16.9), Emulgen LS114 (polyoxyalkylene alkyl ether, HLB: 14), Emulgen LS106 (polyoxyalkylene alkyl ether, HLB: 12.5), Emulgen LS110 (polyoxyalkylene alkyl ether, HLB: 13.4) (all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.); Neugen XL- 70 (polyoxyalkylene branched decyl ether, HLB: 13.2), Neugen XL-140 (polyoxyalkylene branched decyl ether, HLB: 15.9), Neugen XL-400 (polyoxyalkylene branched decyl ether) , HLB: 18.4), Neugen TDS-70 (polyoxyethylene tridecyl ether, HLB: 12.1), Neugen TDS-120 (polyoxyethylene tridecyl ether, HLB: 14.8), Neugen TDS-500F (Polyoxyethylene tridecyl ether, HLB: 18.3) (all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

The HLB value of the nonionic emulsifier is preferably from 10 to 20, particularly preferably from 12 to 19, from the viewpoint of good compatibility.

In addition, as long as the concentration of the nonionic emulsifier in the aqueous coating component (I) is 0.5 to 5% by mass / resin solid content, for example, alkylbenzene sulfonate, alkylnaphthalene sulfonate, higher fatty acid salt, alkyl phosphorus Anionic emulsifiers such as acid ester salt, alkyl ether phosphate ester salt, phosphate ester salt, perfluoroalkyl fatty acid salt; polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, methyl cellulose, hydroxypropyl cellulose, sodium polyacrylate, ethylene-anhydrous A protective colloid of a water-soluble polymer compound such as a maleic acid copolymer may coexist.

As the emulsifier other than the nonionic emulsifier in the aqueous coating component (I), it is particularly preferable that an aromatic anionic emulsifier and a non-aromatic nonionic emulsifier are included.

Although the density | concentration of the fluororesin in water-based coating component (I) changes with uses etc., it should just select from the range of 20-80 mass% normally.

Hydrophilizing agent component (II), which is another component of the aqueous coating composition of the present invention, contains an organosilicate compound (C). As the organosilicate compound as the hydrophilizing agent, in addition to the compounds described in Patent Documents 1 to 5 and the like, compounds described in International Publication No. 94/06870 pamphlet can also be used in the present invention. By hydrolyzing, it becomes a hydrophilic group, and by making the surface of the coating film hydrophilic, an effect of preventing contamination is exhibited.

Examples of the organosilicate compound include, for example, formula (II): Si (OR) ₄ (wherein R is an organic group having 1 to 20 carbon atoms which may be substituted with a hydrogen atom or a halogen atom, for example, linear or branched) Or a condensate thereof; or at least one OR of a tetrafunctional organosilicate compound of the formula (II) or a condensate thereof Organosilicate compounds having a nonionic modified alkyl group substituted with an organic group containing a nonionic group such as a polyoxyalkylene chain (including polyoxyethylene chain necessarily); for example, tetradiethoxysilane, tetratriethoxysilane, tetra Propoxysilane, tetradipropoxysilane, dipolyethoxysilane Ethoxy tripropoxysilane, an ethoxy tributoxysilane silane and the like. An organosilicate compound having 1 to 3 functional groups may be used as long as it has hydrophilicity.

Examples of the tetrafunctional organosilicate compound represented by the formula (II) include tetrahydroxysilane; tetraalkoxysilane such as tetramethoxysilane and tetraethoxysilane; and condensates thereof.

As the organosilicate compound (C), those having a nonion-modified alkyl group are particularly preferred.
Preferred examples of nonionic modified organosilicate compounds include modified organosilicate compounds in which at least one hydrolyzable group contains an alkylene oxide chain, such as an ethylene oxide chain. In addition, the propylene oxide chain and the butylene oxide chain may be included.

Of these, alkylene oxide-modified organosilicate and ethylene oxide-modified organosilicate are preferred from the viewpoint of good storage stability.

The hydrophilizing agent component (II) does not necessarily need to contain a nonionic emulsifier, but may be added to further improve the uniform dispersibility with the water-based paint component (I). The nonionic emulsifier to be blended may be the same as or different from that blended with the water-based paint component (I).

The hydrophilizing agent component (II) is usually preferably used in an amount of 1 to 40 parts by mass, and more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the fluororesin of the water-based paint component (I).

In the aqueous coating composition of the present invention, the aqueous coating component (I) and the hydrophilizing agent component (II) are present separately. The aqueous paint component (I) and the hydrophilizing agent component (II) are mixed immediately before coating to form a uniform composition, and then coated. The aqueous coating composition of the present invention uses a fluororesin having a specific acid value in the aqueous coating component (I), and further blends a specific amount of a nonionic emulsifier to uniformly form an organosilicate compound as a hydrophilizing agent. At the same time, the hydrolysis of the organosilicate compound can be controlled appropriately, so that the time (pot life) that can be applied after mixing can be greatly prolonged.

In the past, non-aromatic nonionic emulsifiers were mixed with organosilicate in advance during the synthesis of hydrophilizing component (II) to improve dispersibility, but about 100 parts by mass with respect to 100 parts by mass of organosilicate. When only about 50 parts by mass is used, it is necessary to additionally use 50 parts by mass of an alcohol component or the like (100 parts by mass of organosilicate). This time, nonionic emulsifiers, particularly aromatic anionic emulsifiers and non-aromatic nonionic emulsifiers are used in combination with water-based paint component (I), thereby reducing the amount of nonionic emulsifier (1-12 parts by mass / hydrophilizing agent). 100 parts by mass) provides effective chemical stability and dispersibility of the hydrophilizing agent.

In the present invention, usually no curing agent is used. Therefore, hydrazide compounds used as curing agents are not added. However, catalysts that promote the hydrolysis of organosilicate compounds as hydrophilizing agents, such as organotin compounds such as butyltin trioctoate and dibutyltin dilaurate, metal alkoxides, Lewis acids, organic or inorganic proton acids, etc. should be added. May be.

The aqueous coating composition of the present invention may be blended with usual coating additives. For example, when preparing an aqueous coating composition containing a pigment, water, a pigment such as titanium oxide, an antifoaming agent, a thickener, and a pigment dispersing agent are previously added to the aqueous coating component (I) with a pigment dispersing machine such as a sand mill. Then, after stirring and mixing a predetermined amount of the pigment dispersion in which the pH adjusting agent and the like are dispersed and a predetermined amount of the film-forming auxiliary, a predetermined amount of the thickener is added and mixed, and other necessary additives may be added as appropriate. When preparing an aqueous coating composition without adding pigments, water, a film-forming auxiliary, an antifoaming agent, a thickener, a pH adjuster, and other required additives as required for the aqueous coating component (I) And stirring and mixing may be performed by a known method.

Additives for paint applications include film-forming aids, antifreeze agents, pigments, fillers, pigment dispersants, antifoaming agents, leveling agents, rheology modifiers, preservatives, UV absorbers, and light stability Agents, antioxidants, matting agents, lubricants, vulcanizing agents and the like can also be added.

The base material to which the aqueous coating composition of the present invention is applied is not particularly limited, and metal base materials such as hot-dip plated steel plate, stainless steel plate, aluminum steel plate, slate, ceramic sizing material, foamed concrete, glass, etc. Ceramic base material; applicable to plastic base materials such as polyvinyl chloride sheet, PET film, polycarbonate, acrylic film. Examples of the hot dip galvanized steel sheet include a hot dip galvanized steel sheet, a hot dip zinc-aluminum-magnesium alloy plated steel sheet, a hot dip galvanized steel sheet, and a hot dip aluminum plated steel sheet.

Conventionally known methods and conditions can be employed as a method for coating the aqueous coating composition of the present invention on various substrates. For example, a coating method such as spray coating, roll coating, flow coating, roller, or brush painting can be employed on the substrate.

The drying method after coating is not particularly limited, and may be natural drying at ambient temperature, or may be drying at a low temperature (5 to 60 ° C.) over a drying time at a high temperature (60 ° C. or more) in a short time. May be dried.

The paint composition includes a weather-resistant paint composition, particularly a weather-resistant paint composition for construction and building materials, a paint composition for interior / exterior of automobiles, a composition for interior / exterior paint of electrical products, office equipment or kitchen appliances. The coating composition can be advantageously applied to a weather-resistant coating composition for building materials from the viewpoint of good weather resistance and durability.

Next, the present invention will be described based on examples, but the present invention is not limited only to these examples.

Example 1
(Preparation of water-based paint component (I))
An aqueous dispersion of VdF / TFE / CTFE copolymer (= 72.1 / 14.9 / 13 (mol%)) (VTC) particles as VdF polymer seed particles (solid content concentration: 45.5 mass%) 131g was charged into a 0.5L glass separable four-necked flask equipped with a stirring blade, cooling tube, and thermometer, and Newcol was used as a surfactant to ensure the stability of seed particles during seed polymerization. 13.1 g of 707SF (manufactured by Nippon Emulsifier Co., Ltd.) and 84 g of water were added. The mixture was heated in a water bath with stirring, and the temperature in the flask was raised to 75 ° C. Separately, 77.6 g / 44.39 g / 2.4 g / 1.1 g acrylic polymer of methyl methacrylate (MMA), butyl acrylate (BA), acrylic acid (AA) and RUVA 93 (manufactured by Otsuka Chemical Co., Ltd.) A mixed monomer solution was prepared, and 16 g of a 1% aqueous solution of ammonium persulfate (APS) was dropped into the flask over 2 hours, followed by seed polymerization. 2.5 hours after the start of the polymerization, the temperature in the flask was raised to 80 ° C., held for 2 hours, cooled, neutralized with aqueous ammonia to adjust the pH to 7, filtered through a 400 mesh wire mesh, and blue 369.6 g of an aqueous dispersion of white acrylic-fluorine composite polymer particles (average particle size 210 nm) was produced. The obtained acrylic-fluorine composite polymer had a fluorine content of 40% by mass and an acid value of 10 mgKOH / g. Moreover, resin solid content in the obtained acrylic-fluorine composite polymer aqueous dispersion was 50 mass%.

Next, 3.7 g of Emulgen 120 (polyoxyethylene lauryl ether, HLB: 15.3, 50% aqueous solution) as a nonionic emulsifier was added and mixed well to prepare an aqueous coating component (I).

(Mixing of water-based paint component (I) and hydrophilizing agent component (II))
100 g of the aqueous paint component (I) prepared above (emulsion having a resin content of 50% by mass) and 8 g of nonionic modified organosilicate (ethylene oxide modified organosilicate) as a hydrophilizing agent component (II) until uniform with a stir bar The state of the obtained liquid mixture was evaluated by the following method. The results are shown in Table 1.

(1) At the time of appearance mixing, 1 hour after mixing, 3 hours after mixing, 16 hours after mixing, and 40 hours after mixing, the state of the liquid is visually observed. Storage is performed at 20 ° C. and a humidity of 65% RH.
A: No abnormality B: Foreign matter (grains) is generated C: Gelation

(2) Viscosity Measured at 60 rpm in accordance with JIS K5600-2-2.

Examples 2-3
Example 1 except that a monomer mixture in which the copolymerization ratio of acrylic acid (AA) was adjusted to 1.1% and 2.8%, respectively, was used as the acrylic monomer mixture for the acrylic polymer. In the same manner, seed polymerization was performed to obtain an acrylic-fluorine composite polymer having acid values of 6 mgKOH / g and 15 mgKOH / g, respectively.

Using the obtained aqueous dispersion of polymer particles, a liquid mixture for clear paint was prepared by mixing with the hydrophilizing agent component (II) in the same manner as in Example 1, and the storage state of the liquid mixture was examined. The results are shown in Table 1.

Comparative Example 1
In Example 1, an aqueous coating component for comparison was prepared in the same manner except that an aqueous dispersion of acrylic-fluorine composite polymer particles having an acid value of 2.4 mgKOH / g was used instead of the aqueous coating component (I). In the same manner as in Example 1, it was mixed with the hydrophilizing agent component (II) to prepare a liquid mixture for clear paint, and the storage state of the liquid mixture was examined. The results are shown in Table 1.

From Table 1, it can be seen that the pot life can be adjusted by the acid value.

Example 4
Emulgen 120 (polyoxyethylene lauryl ether, HLB value 15.3) was added to an aqueous dispersion (ammonia neutralized product) of acrylic-fluorine composite polymer particles having an acid value of 10 mgKOH / g produced in Example 1 at 1% by mass / Water-based paint component (I) was prepared by adding resin solids.

Next, the hydrophilizing agent component (II) was mixed in the same manner as in Example 1, and the obtained mixed solution was applied onto a glass plate with an applicator 10MIL and dried at 25 ° C. for 1 day to form a coating film. .

About the obtained coating film, the haze value, the light transmittance, and the glossiness were measured in the following manner. The results are shown in Table 2.

(Haze value and transmittance)
Measuring device: Hazeguard II (Toyo Seiki Seisakusho)
Measurement method: Haze of transparent plastic, light transmittance standard test method ASTM D 1003 compliant.
The smaller the haze value (%), the higher the transparency, and the higher the light transmittance (%), the higher the transparency.

(Glossy)
Measuring device: Variable angle gloss meter (Nippon Denshoku Industries Co., Ltd. VGS-SENSOR)
The 60 ° specular gloss is examined according to JIS K 5400-6.7.

Examples 5-14
In Example 4, instead of Emulgen 120 as a nonionic emulsifier, Emulgen 123P (HLB value 16.9), Emulgen LS106 (HLB value 12.5), Emulgen LS110 (HLB value 13.4), Emulgen LS114 (HLB value) 14), Neugen XL-70 (HLB value 13.2), Neugen XL-140 (HLB value 15.9), Neugen XL-400 (HLB value 18.4), Neugen TDS-70 (HLB value 12.1), A liquid mixture was prepared in the same manner except that Neugen TDS-120 (HLB value 14.8) and Neugen TDS-500F (HLB value 18.3) were used, and a coating film was formed. The rate and gloss were measured. The results are shown in Table 2.

Example 15
133 g of water was charged into a 0.5 L glass separable four-necked flask equipped with a stirring blade, a cooling tube, and a thermometer, and heated in a water bath with stirring, and the temperature in the flask was raised to 75 ° C. Separately, New Coal 707SF (manufactured by Nippon Emulsifier Co., Ltd.) 12.9 g, water 130 g, methyl methacrylate (MMA), butyl acrylate (BA) and acrylic acid (AA) 119.7 g / 74.0 g / 3.9 g acrylic The mixed monomer solution for the polymer was emulsified with a homogenizer, and an emulsion was prepared by adding 31.6 g of a 1% aqueous solution of ammonium persulfate (APS). The emulsion was dropped into the flask over 2 hours for polymerization. 2.5 hours after the start of the polymerization, the temperature in the flask was raised to 80 ° C., held for 2 hours, cooled, neutralized with aqueous ammonia to adjust the pH to 7, filtered through a 400 mesh wire mesh, and blue 505.1 g of an aqueous dispersion of white acrylic polymer particles (average particle size 131 nm) was produced. The acid value of the obtained acrylic polymer was 15 mgKOH / g. Moreover, the resin solid content in the obtained acrylic polymer aqueous dispersion was 50 mass%.

Except for using the obtained acrylic polymer aqueous dispersion, a nonionic emulsifier was mixed in the same manner as in Example 8 to prepare an aqueous coating component (I), and a hydrophilizing agent component (II) was further mixed. The obtained mixed solution was applied on a glass plate with an applicator 10MIL, dried at 25 ° C. for 1 day to form a coating film, and the haze value, light transmittance and gloss were measured. The results are shown in Table 2.

Comparative Example 2
In Example 4, a mixed solution was prepared in the same manner except that the nonionic emulsifier was not added, a coating film was formed, and the haze value, light transmittance, and gloss were measured. The results are shown in Table 2.

From Table 2, it can be seen that the compatibility is improved by previously mixing the nonionic emulsifier with the aqueous paint component.

Claims (4)

(I) A water-based paint component containing a synthetic resin (A) having an acid value of 2.5 to 20 mg KOH / g and a nonionic emulsifier (B), and (II) a hydrophilic containing a water-dispersible organosilicate compound (C) Containing an agent component,
Content of nonionic emulsifier (B) in water-based paint component (I) is 0.5 to 5% by mass / resin solid content. The two-component water-based paint composition according to claim 1, wherein the synthetic resin (A) is a fluorine-acrylic composite resin, a fluororesin or an acrylic resin. The two-component aqueous coating composition according to claim 1 or 2, wherein the nonionic emulsifier (B) has an HLB value of 10 to 20. The two-component water-based coating composition according to any one of claims 1 to 3, wherein the water-dispersible organosilicate compound (C) has a nonionic-modified alkyl group.