JP2016069385A - Aqueous coating material and coated article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated film excellent in stain resistance by exhibiting high hydrophilic property and to provide an aqueous coating material excellent in coating workability with high thixotropy and excellent in storage stability.SOLUTION: There is provided an aqueous coating material containing a polymer (I), a colloidal silica (II), an organic solvent having solubility to water of 100 g under a condition of 20°C of 2 g or more (III), an alkali swelling type thickening (IV) and a nonion-based surfactant having HLB of 16 or more with the colloidal silica (II) of 0.1 to 18 pts.mass and the nonion-based surfactant (V) of 0.01 to 10 pts.mass based on 100 pts.mass of the polymer (I). There is also provided a coated film obtained from the aqueous coating material.SELECTED DRAWING: None

Description

  The present invention relates to an aqueous coating material and a coated article.

In recent years, in the paint field, conversion from organic solvent-based paints to water-based paints has been attempted from the viewpoints of environmental protection and safety and health. However, water-based paints have the problems of low coating stability such as storage stability, stain resistance, and water resistance compared to organic solvent-based paints, and water-based paints have been developed to solve these problems. ing.
For example, an emulsion of an acrylic resin by emulsion polymerization has attracted attention as a resin for water-based paints because of the characteristic that the resulting coating film has relatively good weather resistance and the like.

  For example, Patent Document 1 discloses a nonionic interface having an acrylic polymer obtained by copolymerizing a monomer containing a monomer having two or more radical polymerizable groups, colloidal silica, and an HLB of 16 or more. An aqueous coating material having an excellent antifouling property containing an active agent is disclosed.

  Patent Document 2 also has excellent water resistance, including an acrylic polymer obtained by copolymerizing a monomer containing an organic alkoxysilane having a radical polymerizable group, colloidal silica, and a surfactant. An aqueous coating material is disclosed.

WO2010 / 143413 pamphlet JP 7-157709 A

  However, the water-based coating material described in Patent Document 1 has low thixotropy, and has a problem in paintability, such as a problem of “sag” depending on the application to be used. Moreover, since the aqueous coating material described in Patent Document 2 does not contain a nonionic surfactant having an HLB of 16 or more, hydrophilicity does not develop, and when used in exterior applications, etc., it has stain resistance. It was insufficient. An object of the present invention is to provide an aqueous coating material having excellent coating workability due to the high thixotropy of the aqueous coating material, and further excellent in storage stability and stain resistance of the coating film obtained from the aqueous coating material. It is in.

  The first gist of the present invention is a polymer (I), colloidal silica (II), an organic solvent (III) having a solubility in 100 g of water at 20 ° C. of 2 g or more, an alkali swelling thickener ( IV) and an aqueous coating material containing a nonionic surfactant (V) having an HLB of 16 or more, and 0.1 to 18 parts by mass of colloidal silica (II) with respect to 100 parts by mass of the polymer (I). Aqueous coating material containing 0.01 to 10 parts by mass of nonionic surfactant (V). The second gist of the present invention resides in a coating film obtained from the aqueous coating material.

  Since the aqueous coating material of the present invention has high thixotropy, it is excellent in coating workability and storage stability. Moreover, the coating film obtained from the aqueous coating material of the present invention has excellent stain resistance.

<Water-based coating material>
Hereinafter, the aqueous coating material of the present invention will be described in detail.
The aqueous coating material of the present invention comprises a polymer (I), colloidal silica (II), an organic solvent (III) having a solubility in 100 g of water of 2 g or more at 20 ° C., an alkali swelling thickener (IV ) And a nonionic surfactant (V) having an HLB of 16 or more.

[Polymer (I)]
The polymer (I) of the present invention can be obtained by polymerizing a radical polymerizable monomer or a radical polymerizable monomer mixture in at least one stage.
Preferably, the hydrolyzable silyl group-containing radically polymerizable monomer and / or the monomer (a) having two or more radically polymerizable groups, the carboxyl group-containing radically polymerizable monomer (b), and other single monomers. It is a polymer obtained by polymerizing a radical polymerizable monomer mixture containing the monomer (c).

<Monomer (a)>
The monomer (a) is a hydrolyzable silyl group-containing radical polymerizable monomer and / or a monomer having two or more radical polymerizable groups. By using the monomer (a), a coating film excellent in stain resistance, weather resistance and water resistance can be obtained.

  Examples of the hydrolyzable silyl group-containing radical polymerizable monomer include vinyl silanes such as vinylmethyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldichlorosilane, and vinyltrichlorosilane; γ-acryloyloxyethyl Methyldimethoxysilane, γ-acryloyloxyethyltrimethoxysilane, γ-acryloyloxyethyltriethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-acryloyloxypropyltriethoxysilane, γ -Acryloyloxyethylmethyldichlorosilane, gamma-acryloyloxyethyltrichlorosilane, gamma-acryloyloxypropylmethyldichlorosilane, gamma-acrylic Acryloyloxyalkylsilanes such as yloxypropyltrichlorosilane; γ-methacryloyloxyethylmethyldimethoxysilane, γ-methacryloyloxyethyltrimethoxysilane, γ-methacryloyloxyethyltriethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ -Methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-methacryloyloxyethylmethyldichlorosilane, γ-methacryloyloxyethyltrichlorosilane, γ-methacryloyloxypropylmethyldichlorosilane, γ-methacryloyloxypropyltrichlorosilane And methacryloyloxyalkylsilanes.

  Examples of the monomer having two or more radically polymerizable groups include ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, Polypropylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2-hydroxy-1,3-di (Meth) acryloxypropane, 2,2-bis [4- (acryloxyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4- ( Acryloxy polyethoxy) phenyl Propane, 2,2-bis [4- (methacryloxy polyethoxy) phenyl] propane, 2-hydroxy-1-acryloxy-3-methacryloxypropane, ethylene oxide modified bisphenol A di (meth) acrylate, propylene oxide modified bisphenol A di (Meth) acrylate, ethylene oxide-modified hydrogenated bisphenol A di (meth) acrylate, propylene oxide-modified hydrogenated bisphenol A di (meth) acrylate, diglycidyl ether of bisphenol A and hydroxyalkyl (meth) such as hydroxy (meth) acrylate Diester compound of (meth) acrylic acid with diol such as epoxy (meth) acrylate with added acrylate, polyoxyalkylenated bisphenol A di (meth) acrylate, etc. Metal-containing radical polymerizable monomers such as zinc di (meth) acrylate; trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri ( (Meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and other compounds having 3 or more hydroxyl groups per molecule and polyester of (meth) acrylic acid Compound: Allyl (meth) acrylate, divinylbenzene, ε-caprolactone-modified tris (acryloxyethyl) isocyanurate.

In particular, by including a monomer having two or more allyl groups, the stain resistance and water resistance of the obtained coating film are further improved. Among them, triallyl cyanurate, triallyl isocyanurate, diallyl iso (tere) phthalate, diallyl isocyanurate, diallyl maleate and the like are preferable, and triallyl cyanurate and triallyl isocyanurate having three allyl groups are most preferable.
As the monomer (a), only one type may be used alone, or two or more types may be used in combination.

  The content of the monomer (a) is preferably 0.2 to 10% by mass and more preferably 0.3 to 5% by mass with respect to a total of 100% by mass of the monomer mixture. . More preferably, it is 0.5-3 mass%, Most preferably, it is 0.5-2 mass%. If content of a monomer (a) is in the said range, the coating film excellent in stain resistance, a weather resistance, and water resistance will be obtained.

<Monomer (b)>
The monomer (b) is a carboxyl group-containing radical polymerizable monomer. By using the monomer (b), excellent stain resistance and storage stability can be obtained.
Examples of the carboxyl group-containing radical polymerizable monomer include (meth) acrylic acid, itaconic acid, citraconic acid, maleic acid, monomethyl maleate, monobutyl maleate, monomethyl itaconate, monobutyl itaconate, vinylbenzoic acid, Acid monohydroxyethyl (meth) acrylate, tetrahydrophthalic acid monohydroxyethyl (meth) acrylate, tetrahydrophthalic acid monohydroxypropyl (meth) acrylate, 5-methyl-1,2-cyclohexanedicarboxylic acid monohydroxyethyl (meth) acrylate, Monohydroxyethyl (meth) acrylate phthalate, Monohydroxypropyl (meth) acrylate phthalate, Monohydroxyethyl (meth) acrylate maleate, Hydroxypropyl maleate ( Data) acrylate, tetrahydrophthalic acid mono-hydroxybutyl (meth) acrylate.
Acrylic acid is preferred from the viewpoint of stain resistance of the resulting coating film.
A monomer (b) may be used individually by 1 type, and may use 2 or more types together.
The content of the monomer (b) is preferably 0.1 to 5% by mass and more preferably 0.5 to 2% by mass with respect to 100% by mass in total of the monomer mixture. . If content of a monomer (b) is in the said range, the coating film excellent in stain resistance, a weather resistance, and water resistance will be obtained.

<Monomer (c)>
The monomer (c) is a radical polymerizable monomer other than the monomer (a) and the monomer (b).

  Examples of other radical polymerizable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, sec-butyl (meth) acrylate, t -Alkyl (meth) acrylates having an alkyl group of 1 to 18 carbon atoms such as butyl (meth) acrylate, glycidyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, etc. Hydroxyl group-containing radical polymerizable monomers such as 2-hydroxyethyl (meth) acrylate; terminal hydroxy type poly such as hydroxypolyethylene oxide mono (meth) acrylate and hydroxypolypropylene oxide mono (meth) acrylate Rulylene oxide group-containing radical polymerizable monomer; alkyl group-terminated polyalkylene oxide group-containing radical such as methoxypolyethylene oxide mono (meth) acrylate; oxirane group-containing radical polymerizable monomer such as glycidyl (meth) acrylate; (Meth) acrylate having a light stabilizing action such as 1,2,2,6,6-pentamethyl-4-piperidyl (meth) acrylate, 2,2,6,6-pentamethyl-4-piperidyl (meth) acrylate; (Meth) acrylate having an ultraviolet-absorbing component such as 2- [2′-hydroxy-5 ′-(meth) acryloyloxyethylphenyl] -2H-benzotriazole; Aminoalkyl such as 2-aminoethyl (meth) acrylate ( (Meth) acrylates; amide groups such as (meth) acrylamide Radical polymerizable monomers; metal-containing radical polymerizable monomers such as zinc di (meth) acrylate; (meth) acrylonitrile, benzyl (meth) acrylate, isobornyl (meth) acrylate, methoxyethyl (meth) acrylate, etc. Other (meth) acrylic monomers; aromatic vinyl monomers such as styrene and methylstyrene; ethylenic compounds containing carbonyl groups and / or aldehyde groups such as acrolein, diacetone acrylamide, formyl styrene, vinyl alkyl ketone Unsaturated monomers: Conjugated diene monomers such as 1,3-butadiene and isoprene; and radical polymerizable monomers such as vinyl acetate, vinyl chloride and ethylene.

Furthermore, in this invention, it is preferable that a monomer (c) contains a carbonyl group and / or an aldehyde group containing ethylenically unsaturated monomer. Examples of the carbonyl group and / or aldehyde group-containing ethylenically unsaturated monomer include acrolein, diacetone acrylamide, formylstyrene, vinyl methyl ketone having 4 to 7 carbon atoms, vinyl ethyl ketone, vinyl isobutyl ketone, and (meth) acrylic. Examples thereof include oxyalkylpropanal, (meth) acrylamide, pivalinaldehyde, diacetone (meth) acrylate, acetonyl acrylate, acetoacetoxyethyl (meth) acrylate, and the like.
An organic hydrazine compound having at least two hydrazino groups in the molecule (hereinafter referred to as “hydrazine compound”) is added to the aqueous coating material of the present invention containing the polymer (I) copolymerized with these monomers. When converted into a paint, a crosslinking reaction proceeds between the carbonyl group in the polymer (I) and the hydrazino group of the hydrazine compound, and a coating film excellent in stain resistance, weather resistance, and water resistance is obtained.
It is preferable that content of the said monomer is 0.2-10 mass% with respect to a total of 100 mass% of a monomer mixture.

  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, and glutaric acid. Dihydrazides of dicarboxylic acids having 2 to 15 carbon atoms such as dihydrazide, adipic acid 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-methylmercap) Compounds having a hydantoin skeleton ethyl) hydantoin, and the like.

  A hydrazine compound may be used individually by 1 type, and may use 2 or more types together. The ratio of the monomer to the hydrazine compound is such that the number of moles of the monomer contained in the total amount of the monomer mixture is (P), and the hydrazino of the hydrazine compound blended in the dispersion of the polymer (I). When the number of moles of the group is (Q), the ratio (P) / (Q) is preferably 0.1 to 10, and more preferably 0.8 to 2. If (P) / (Q) is 0.1 or more, it is easy to suppress a decrease in water resistance of the coating film due to the unreacted hydrazine compound. When (P) / (Q) is 10 or less, the stain resistance, weather resistance, and water resistance of the coating film are further improved.

  In the present invention, the monomer mixture is preferably copolymerized in an aqueous dispersion containing a polyorganosiloxane polymer. By copolymerizing the monomer mixture in an aqueous dispersion containing a polyorganosiloxane polymer, a polymer (I) containing a polyorganosiloxane polymer is obtained.

Examples of the polyorganosiloxane polymer include dimethyldialkoxysilanes such as dimethyldimethoxysilane and dimethyldiethoxysilane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, It can be synthesized by a known method using dimethylsiloxane cyclic oligomers such as tetradecamethylcycloheptasiloxane and dimethylcyclics (dimethylsiloxane cyclic oligomer 3-7 mer mixture), dimethyldichlorosilane and the like as raw materials.
It is preferable to use a dimethylsiloxane cyclic oligomer from the viewpoint of excellent performance such as thermal stability and cost of the obtained aqueous coating agent.
Furthermore, in order to improve the transparency of the resulting coating film, it is more preferable to copolymerize the hydrolyzable silyl group-containing radical polymerizable monomer with the above-described dimethylsiloxane cyclic oligomer, dimethyldichlorosilane, or the like.

The mass average molecular weight of the polyorganosiloxane polymer is preferably 10,000 or more, and more preferably 50,000 or more. When the mass average molecular weight of the polyorganosiloxane polymer is 10,000 or more, sufficient weather resistance is easily exhibited in the obtained coating film.
The polyorganosiloxane polymer is preferably used in an amount of 0.3 to 50 parts by mass in the polymer (I) from the viewpoint of stain resistance, water resistance and weather resistance. More preferably, it is 0.5-10 mass parts, More preferably, it is 0.5-3 mass parts.

The average particle size of the polymer (I) is preferably 80 to 200 nm, and preferably 80 to 170 nm in order to have excellent hydrophilicity, stain resistance and weather resistance, water resistance, and frost damage resistance. It is more preferable. More preferably, it is 100-150 nm. When the average particle size is 80 nm or more, the storage stability of the aqueous coating material obtained by the present invention and the stain resistance of the coating film are likely to be improved. Moreover, the water resistance of a coating film is easy to improve that an average particle diameter is 200 nm or less.
The average particle size of the polymer (I) is determined by a cumulant analysis method that calculates the average particle size by applying the scattering intensity distribution caused by the fine particles detected by the dynamic light scattering method to the normal distribution. This measurement is carried out by using a dense particle size analyzer FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.) and analyzing with attached software.

[Colloidal silica (II)]
Colloidal silica (II) is a component that imparts hydrophilicity to the coating film obtained from the aqueous coating material of the present invention, thereby improving stain resistance.
Examples of the colloidal silica (II) include acidic aqueous colloidal silica, alkaline aqueous colloidal silica, and cationic colloidal silica.
Examples of the aqueous colloidal silica exhibiting acidity include trade name: Snowtex O (SiO2 solid content 20%, manufactured by Nissan Chemical Industries, Ltd.).

Examples of the aqueous colloidal silica exhibiting alkalinity include, for example, product names manufactured by Nissan Chemical Industries, Ltd .: Snowtex XS (SiO2 solid content 20%), Snowtex NXS (SiO2 solid content 20%), Snowtex N (SiO2 solid content) Mintex 20%), Snowtex S (SiO2 solid content 30%), Snowtex NS (SiO2 solid content 20%) and the like.
Examples of the cationic colloidal silica include Snowtex AK (manufactured by Nissan Chemical Industries, Ltd., SiO2 solid content 19%). These colloidal silicas may be used alone or in combination of two or more.
The colloidal silica (II) may be one using water as a dispersion medium or one using an organic solvent as a dispersion medium.

  Content of colloidal silica (II) in the aqueous coating material of this invention is 0.1-18 mass parts in conversion of solid content with respect to 100 mass parts of polymers (I). When the content of the colloidal silica (II) is 0.1 parts by mass or more, excellent stain resistance and excellent storage stability can be obtained. Moreover, if content of the said colloidal silica (II) is 18 mass parts or less, the outstanding stain resistance and the outstanding storage stability will be obtained, without reducing the water resistance of a coating film. The content of the colloidal silica (II) is preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts by mass.

  The average particle size of the colloidal silica (II) is preferably 1 to 60 nm, more preferably less than 40 nm, and even more preferably less than 20 nm. If the average particle size is 60 nm or less, the colloidal silica (II) is unevenly distributed in the coating surface layer in the drying step of the aqueous coating material obtained by the present invention, and the contamination resistance is likely to be improved.

[Organic solvent (III) having a solubility in 100 g of water of 2 g or more at 20 ° C.]
The aqueous coating material of the present invention needs to contain an organic solvent (III) having a solubility in 100 g of water of 2 g or more under 20 ° C. conditions. The organic solvent (III) improves the film formability and hydrophilicity of the coating film obtained from the aqueous coating material of the present invention, and a coating film excellent in stain resistance, weather resistance and water resistance can be obtained. Furthermore, it has the effect of improving the storage stability of the aqueous coating material. The solubility is preferably 2 g or more and less than 40 g, more preferably 2 g or more and less than 20 g.

Examples of the organic solvent (III) include linear, branched or cyclic aliphatic alcohols; alcohols containing an aromatic group; general formula HO— (CH ₂ CHXO) _p —R ¹ (wherein R ¹ is a linear or branched alkyl group having 1 to 10 carbon atoms, X is a hydrogen atom or a methyl group, and p is an integer of 5 or less.) (Poly) ethylene glycol or monoethers of (poly) propylene glycol, and the like; in the general formula ^{_{R 2 COO- (CH 2 CHXO)}} q -R 3 ( wherein, ^{R 2} and ^{R 3} are each independently of 1 to 10 carbon atoms A linear or branched alkyl group, X is a hydrogen atom or a methyl group, and q is an integer of 5 or less. ) Propylene glycol ether esters; and the like.
Preferred are propylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol-n-propyl ether, diethylene glycol monoethyl ether acetate, and 3-methoxy-3-methyl-1-butanol.
Preferably dipropylene glycol n-butyl ether (DPnB, solubility in 100 g of water is 3 g), dimethylpropylene diglycol (DMFDG, solubility in 100 g of water is 37 g), ethylene glycol monobutyl ether (butyl cellosolve, in 100 g of water) Solubility is infinite).

  The organic solvent (III) is preferably added in such an amount that the minimum film-forming temperature of the aqueous coating material is 20 ° C. or lower.

[Alkali swelling thickener (IV)]
Thickeners are blended in order to bring the viscosity of the aqueous coating material to a desired range. Alkali swelling thickeners, urethane-associative thickeners, cellulosic thickeners, natural polymers Thickeners are known. In the present invention, it is necessary to use an alkali swelling type thickener.
The alkali swelling type thickener generally has a function of increasing the viscosity of the system by swelling a copolymer having a high acid value by alkali neutralization. Examples of such thickeners include polyacrylic acid thickeners.

Examples of the polyacrylic acid thickener include polyacrylic acid, polyacrylic acid-poly (meth) acrylic acid alkyl ester copolymer (acrylic acid copolymer), and the like. Moreover, as a polyacrylic acid type | system | group thickener, the neutralized material by which the above-mentioned polyacrylic acid was neutralized previously, ie, polyacrylate, etc. are mentioned. Examples of the polyacrylate include sodium polyacrylate and potassium polyacrylate. Examples of the polyacrylic acid thickener include hydrophobic group-modified polyacrylic acid in which a part of the carboxyl group is modified with a hydrophobic group such as a styrene group or an alkyl group.
The acid value of the polyacrylic acid thickener is, for example, 30 to 300 mg / KOH, or preferably 80 to 280 mg / KOH.

  As these thickeners, commercially available products can be used. Specifically, for example, primal ASE-60, primal TT-615, primal ASE-75, primal ASE-95, primal ASE-108, primal RM-5. (From Rohm and Haas), Sogen 100, Sogen 150, Sogen 200, Sogen 250, Sogen 350 (from RHEOX), SN thickener A-815, SN thickener A-818, SN thickener A-850, SN thickener 630, SN thickener 636, SN thickener 640 (manufactured by San Nopco), RHEOVIS CR (manufactured by Yushi Co., Ltd.), Aron B-300K, Aron B-500, Aron A-7070 (manufactured by Toagosei) Chikuzol K-150B (Kyoeisha Yushi Chemical Industry) Ltd.), ACRYSET WR-503, ACRYSET WR-650 (all manufactured by Nippon Shokubai Co., Ltd.). Among these, Primal ASE-60 and SN thickener 636 are preferable from the viewpoint of contamination resistance and storage stability.

[Nonionic surfactant (V) having an HLB of 16 or more]
The aqueous coating material of the present invention contains a nonionic surfactant (V) having an HLB of 16 or more. By including a nonionic surfactant (V) having an HLB of 16 or more, the stain resistance of the resulting coating film is improved.
HLB (Hydrophile-Lipophile Balance) is a hydrophilic / lipophilic balance, and is a value calculated by the Griffin method (all revised edition, introduction to surfactants, p128) obtained from the following formula (1).
Nonionic surfactant HLB = (molecular weight of hydrophilic group portion / molecular weight of surfactant) × 20 (1)
The HLB value is preferably 17 or more, and more preferably 18 or more because the hydrophilicity of the resulting coating film surface is further increased.

  Examples of the nonionic surfactant (V) having an HLB of 16 or more include polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenol ethers, polyoxyalkylene aryl ethers, polyoxyalkylene alkyl aryl ethers, sorbitan derivatives, polyoxyalkylene aryls. Examples include a formalin condensate of ether and a formalin condensate of polyoxyalkylene alkylaryl ether. Among these, polyoxyalkylene alkyl ether is particularly preferable.

  Examples of the alkyl part of the polyoxyalkylene alkyl ether in the nonionic surfactant (V) include a linear or branched alkyl group having 1 to 36 carbon atoms. Moreover, it is preferable that the polyoxyalkylene part of polyoxyalkylene alkyl ether is a polyoxyethylene from the point from which the coating film which has the especially outstanding hydrophilic property and antistatic property is obtained. Further, the number of repeating units of polyoxyethylene is preferably 30 or more, and more preferably 40 or more.

Of the nonionic surfactants of polyoxyalkylene alkyl ether, a surfactant represented by the following formula (2) is particularly preferable.
^{_{R 4 O- (C 2 H 4}} 0) m -H (2)
(However, m is 0 or a positive integer, and R ⁴ is a linear or branched alkyl group having 1 to 36 carbon atoms.)
Specific examples of the nonionic surfactant (V) represented by the formula (2) include, for example, Emulgen 1150S-60 (trade name, manufactured by Kao Corporation, R ⁴ : mainly an alkyl group having 11 carbon atoms. , M = 50, HLB = 18.5), Emulgen 1135S-70 (trade name, manufactured by Kao Corporation, R ⁴ : mainly alkyl group having 11 carbon atoms, m = 35, HLB = 17.9), Etc.

  Content of nonionic surfactant (V) in the aqueous coating material of this invention is 0.01-10 mass parts with respect to 100 mass parts of polymers (I). It is preferable that it is 0.01-3 mass parts, and it is more preferable that it is 0.1-2 mass parts. If the said content of nonionic surfactant (V) is 0.01 mass part or more, the stain resistance of the coating film obtained will improve. Moreover, if the said content is 10 mass parts or less, the stain resistance of a coating film will improve, without impairing storage stability and the water resistance of a coating film.

[Other compounds]
In addition, the aqueous coating material of the present invention preferably contains an anionic surfactant.
<Anionic surfactant>
The anionic surfactant, when used in combination with the nonionic surfactant (IV), increases the area of the colloidal silica (II) in the surface of the obtained coating film and improves the stain resistance of the coating film. Fulfill.
The anionic surfactant is not particularly limited, but a polyoxyalkylene aryl ether sulfate ester salt, a polyoxyalkylene alkyl aryl ether sulfate ester salt, and the like are preferable. The above-mentioned sulfate ester salt includes a formalin condensate. These anionic surfactants may be used alone or in combination of two or more.

Specific examples of anionic surfactants include polyoxyalkylene aryl ether sulfate salts such as CP series such as CP-12Na (trade name, manufactured by Toho Chemical Co., Ltd.), New Coal 707SF, and the like. Cole 700 series (trade name, manufactured by Nippon Emulsifier Co., Ltd.), and Hightenol NF series (produced by Daiichi Kogyo Seiyaku Co., Ltd.) such as Hytenol NF-13.
Examples of the formalin condensate of polyoxyalkylene aryl ether sulfate ester salt include SP-185FNa (trade name, manufactured by Toho Chemical Industry Co., Ltd.).
Examples of the formalin condensate of the polyoxyalkylene alkylaryl ether sulfate ester salt include Antox MS-60 (trade name, manufactured by Nippon Emulsifier Co., Ltd.).

  0.5-10 mass parts is preferable with respect to 100 mass parts of polymers (I), and, as for content of the anionic surfactant in an aqueous coating material, it is more preferable that it is 1-5 mass parts. More preferably, it is 2-4 mass parts. If the said content of an anionic surfactant is 0.5-10 mass parts, the stability at the time of paint formulation and storage stability will improve, and the stain resistance of the coating film obtained will improve.

  The solid content of the aqueous coating material of the present invention is preferably 10 to 80% by mass.

  In addition, the aqueous coating material of the present invention has various pigments, antifoaming agents, pigment dispersants, leveling agents, matting agents, ultraviolet absorbers, light stabilizers, oxidation agents from the viewpoint of developing excellent performance as a coating material. Various additives such as inhibitors, heat resistance improvers, slip agents, preservatives, and plasticizers may be included, and polyester resins, polyurethane resins, acrylic resins, acrylic silicone resins, silicone resins, Other emulsion resins such as fluorine resins and epoxy resins, water-soluble resins, melamines, isocyanates and other curing agents can be blended to form an aqueous coating material.

[Production method]
Hereinafter, the manufacturing method of the aqueous coating material of this invention is demonstrated.
The aqueous coating material of the present invention is prepared by preparing polymer (I), colloidal silica (II), organic solvent (III) having a solubility in 100 g of water at 20 ° C. of 2 g or more, alkali swelling type thickening It is obtained by blending agent (IV) and nonionic surfactant (V) having an HLB of 16 or more. The order of blending is not particularly limited.

As a method for preparing the polymer (I), emulsion polymerization is preferred.
As the initiator, those generally used for radical polymerization can be used. For example, persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate, azobisisobutyronitrile, 2,2 ′ -Azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2-phenylazo Oil-soluble azo compounds such as -4-methoxy-2,4-dimethylvaleronitrile; 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propion Amide}, 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 its salts, 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 salts thereof, 2,2′-azobis ( 1-imino-1-pyrrolidino-2-methylpropane) and salts thereof, 2,2′-azobis {2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane} and salts thereof, Water-soluble azotization of 2,2′-azobis (2-methylpropionamidine) and its salts, 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] and its salts Things; benzoyl peroxide, cumene hydroperoxide, t- butyl hydroperoxide, t- butyl peroxy-2-ethylhexanoate, t- butyl organic peroxides of peroxy isobutyrate and the like.

These initiators may be used alone or in combination of two or more.
When acceleration of the polymerization rate and low temperature polymerization at 70 ° C. or lower are desired, 2,2′-azobis [2- (2-imidazolin-2-yl) having a 10-hour half-life temperature of 70 ° C. or lower is desired. It is preferable to use a water-soluble azo compound such as) propane] and its salts, or a reducing agent such as sodium bisulfite, ferrous sulfate, ascorbate, or longalite in combination with a radical polymerization catalyst.
In addition, from the viewpoint of storage stability of water-based coating materials and paints, and water resistance and weather resistance of coating films, organic peroxides such as t-butyl hydroperoxide, ferrous sulfate, ascorbate, etc. A combination of reducing agents is preferred.
The addition amount of the radical polymerization initiator is usually 0.01 to 10 parts by mass with respect to 100 parts by mass of the polymer (I), but 0.02 to 0.02 in view of the progress of polymerization and the control of the reaction. It is preferably 5 parts by mass.

  In the case of adjusting the molecular weight of the polymer (I), as a molecular weight adjusting agent, mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, n-tetradecyl mercaptan, n-hexyl mercaptan; Halogen compounds such as carbon chloride and ethylene bromide; known chain transfer agents such as α-methylstyrene dimer may be used. The usage-amount of a molecular weight regulator is 1 mass part or less normally with respect to 100 mass parts of polymers (I).

In the emulsion particle dispersion obtained by emulsion polymerization, it is preferable to adjust the pH of the system from neutral to weakly alkaline, that is, about pH 6.5 to 11.0 by adding a basic compound after polymerization. Furthermore, it is more preferable to adjust the pH to about 8.5 to 11.0 from the viewpoint of storage stability. Most preferably, the pH is 9.0 to 10.0.
Examples of the basic compound include ammonia, triethylamine, propylamine, dibutylamine, amylamine, 1-aminooctane, 2-dimethylaminoethanol, ethylaminoethanol, 2-diethylaminoethanol, 1-amino-2-propanol, 2- Amino-1-propanol, 2-amino-2-methyl-1-propanol, 3-amino-1-propanol, 1-dimethylamino-2-propanol, 3-dimethylamino-1-propanol, 2-propylaminoethanol, Examples include ethoxypropylamine, aminobenzyl alcohol, morpholine, sodium hydroxide, and potassium hydroxide. Ammonia is preferable.

<Painted object>
The coated product of the present invention is a coated product to which the above-described aqueous coating material is applied.
The coating film obtained by applying the aqueous coating material of the present invention is not particularly limited in the position where the coating film is formed, and is formed on various articles (hereinafter referred to as “substrate” for convenience). Can be painted.
Examples of the substrate include cement mortar, slate board, gypsum board, extruded board, foamable concrete, metal, glass, porcelain tile, asphalt, wood, waterproof rubber material, plastic, calcium silicate base material, PVC sheet, FRP ( (Fiber Reinforced Plastics) substrate and the like. The coating film by the aqueous coating material of the present invention can be positioned for surface finishing of these various substrates.

  Specific examples of the coated material having a coating film obtained by applying the aqueous coating material of the present invention include, for example, building materials, building exteriors, building interiors, window frames, window glass, structural members, plate materials, vehicle exteriors, Exteriors of machinery and articles, dust covers, road sign reflectors, gaze guidance signs, road markings, various displays, advertising towers, road noise barriers, railway noise barriers, road decorative panels, traffic light source covers, outdoor Display boards, bridges, guard rails, tunnel interiors, lighting equipment in tunnels, glass, solar battery covers, solar water heater heat collection covers, tents, greenhouses, vehicle lighting cover, road mirrors, vehicle mirrors, motorcycles Measuring covers and weighing panels, glass lenses, plastic lenses, helmet shields, goggles, houses and window glass for automobiles and railway vehicles, vehicle windshields, showcases, Warm showcase, membrane structure, heat exchange fins, glass surfaces at various locations, blinds, tire wheels, roofing materials, roof tiles, antennas, power lines, housing equipment, toilets, bathtubs, washstands, lighting fixtures, lighting Cover, kitchen utensils, tableware, tableware storage, dishwasher, dish dryer, sink, cooking range, kitchen hood, ventilation fan, aquarium material for viewing, surface materials of parts that come in contact with circulating water in facilities using circulating water, anti-resistance Thrombotic material, anti-protein adhesion material, lipid adhesion prevention material, contact lens, urinary catheter, transdermal device, artificial organ, blood bag, blood collection bag, lung drainage, ship bottom, tent canvas, slide, functional fiber And a display which is a display screen of a television or a personal computer, and a film to be attached to the article.

  As a method of applying the aqueous coating material to the surface of various substrates, for example, various coating methods such as spray coating method, roller coating method, bar coating method, air knife coating method, brush coating method, dipping method, etc. may be appropriately selected. it can. Moreover, after application | coating, the coating film fully formed into a film can be obtained by drying at normal temperature or heat-drying at 40-200 degreeC.

  Since the coated material of the present invention described above is coated with the aqueous coating material of the present invention, it can exhibit excellent stain resistance.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited by the following description. In the present embodiment, “part” means “part by mass”.
The physical property test of the aqueous coating material in the present example was performed by the following method.

[Preparation of test plate for water contact angle evaluation]
Each aqueous coating material was coated on a glass plate with a 4MIL applicator (wet film thickness: about 100 μm) and dried at 30 ° C. for 12 hours. What was dried for 1 day at room temperature after washing with running water was used as a coating plate for evaluation of water contact angle.

[Evaluation method]
(1) Water contact angle automatic contact angle meter DM500 (manufactured by Kyowa Interface Science Co., Ltd.) was used, and 1 μL of distilled water was dropped on the evaluation coating plate in an atmosphere at 23 ° C., and the water contact angle after 30 seconds was measured. did. Evaluation was performed according to the following criteria. The lower the water contact angle, the higher the hydrophilicity of the surface of the resulting coating film, and the contamination resistance is improved by the self-cleaning action of rainwater.
Water contact angle ○: 45 ° or less △: Over 45 ° and 65 ° or less ×: Over 65 °

(2) Storage stability (water contact angle after storage at 50 ° C)
The storage stability is the same as the preparation of the test plate for water contact angle evaluation described above using an aqueous coating material in which each aqueous coating material is enclosed in a glass bottle, immersed in warm water at 50 ° C. and returned to room temperature after 30 days. A test plate for evaluation was prepared by the method, the water contact angle was measured by the same method as the method (1), and the evaluation was performed based on the same criteria.

(3) Thixotropic (TI value)
Viscosity was measured with a TVB-10 viscometer (manufactured by Toki Sangyo Co., Ltd.) at a rotor rotation speed of 6 rpm and 60 rpm, and the viscosity value at 6 rpm was divided by the viscosity value at 60 rpm and evaluated. Evaluation was performed according to the following criteria.
TI value is over: 4.0: over Δ: over 2.0 and below 4.0 ×: below 2.0

[Production Example 1] Preparation of polyorganosiloxane polymer aqueous dispersion The following raw material compositions were premixed with a homomixer and emulsified with a pressure homogenizer at a pressure of 200 kg / cm ² to obtain a pre-emulsion.
Next, water (90 parts) and dodecylbenzenesulfonic acid (10 parts) were charged into a flask equipped with a stirrer, a reflux condenser, a temperature controller and a dropping pump, and the internal temperature of the flask was kept at 85 ° C. with stirring. The pre-emulsion was added dropwise over 4 hours. After completion of the dropwise addition, the polymerization is further allowed to proceed for 1 hour, the resulting polyorganosiloxane copolymer dispersion is cooled, and the following sodium hydroxide aqueous solution is added to obtain a polyorganosiloxane copolymer aqueous dispersion (SiEm). Prepared. The solid content of the SiEm was 18% by mass.
Raw material composition:
3 to 7-mer mixture of cyclic dimethylsiloxane oligomer 98 parts γ-methacryloyloxypropylmethyldimethoxysilane 2 parts deionized water 310 parts sodium dodecylbenzenesulfonate 0.7 part sodium hydroxide aqueous solution:
Sodium hydroxide 1.5 parts Deionized water 30 parts

[Production Example 2] Production of polymer (I) -1 A flask equipped with a stirrer, a reflux condenser, a temperature controller, and a dropping pump was charged with the following SiEm, deionized water, and the first monomer mixture. After raising the internal temperature to 40 ° C., the following reducing agent aqueous solution and first initiator aqueous solution were added. After confirming the peak top temperature due to the polymerization exotherm, the internal temperature of the flask was maintained at 75 ° C.
Initial raw material mixture:
SiEm (solid content: 18%) 5 parts Deionized water 74 parts First monomer mixture:
Methyl methacrylate 6.0 parts 2-Ethylhexyl acrylate 24.0 parts Glycidyl methacrylate 3.0 parts 2-Hydroxyethyl methacrylate 1.0 part Triallyl cyanurate 1.0 part New Coal 707SF (trade name, manufactured by Nippon Emulsifier Co., Ltd.) ) 2.5 parts deionized water 13 parts

Reducing agent aqueous solution:
Iron (II) sulfate heptahydrate 0.0002 parts Ethylenediaminetetraacetic acid 0.00027 parts Sodium L-ascorbate 0.12 parts Deionized water 6 parts First initiator aqueous solution:
Perbutyl H69 (trade name, manufactured by NOF Corporation) 0.02 parts Deionized water 1 part

Subsequently, 0.5 hours after adding the reducing agent aqueous solution, the second monomer mixture was added dropwise over 2.75 hours. Moreover, the 2nd initiator aqueous solution was dripped in parallel over 3 hours from the dripping pump different from a 2nd monomer mixture.

Second monomer mixture:
Methyl methacrylate 36.30 parts n-Butyl methacrylate 22.33 parts 2-Ethylhexyl acrylate 3.20 parts Acrylic acid 1.67 parts Diacetone acrylamide 1.50 parts Newcol 707SF 4.20 parts Deionized water 25 parts Second start Aqueous solution:
Perbutyl H69 0.03 parts Deionized water 5 parts

After maintaining at 75 ° C. for 1 hour, the resulting dispersion was cooled to room temperature, 1.45 parts of 28% aqueous ammonia, 0.7 parts of adipic acid dihydrazide, and 5.0 parts of Neucor 707SF were added, After maintaining at 75 ° C. for 1 hour, the dispersion was cooled to room temperature to obtain an aqueous dispersion of polymer (I) -1. The solid content of the finally obtained aqueous dispersion was 42.2%.

[Production Example 3] Production of polymer (I) -2 Polymer (I) was produced in the same manner as in Production Example 2 except that the first monomer mixture and the second monomer mixture were changed as shown below. -2 aqueous dispersion was obtained. The solid content of the finally obtained aqueous dispersion was 42.2%.

First monomer mixture:
Methyl methacrylate 25 parts n-butyl acrylate 2 parts glycidyl methacrylate 1 part 2-hydroxyethyl methacrylate 1 part triallyl cyanurate 1 part Neucor 707SF 2.5 parts deionized water 13 parts Second monomer mixture:
Methyl methacrylate 20 parts n-butyl methacrylate 26.33 parts 2-ethylhexyl acrylate 20.5 parts Acrylic acid 1.67 parts Diacetone acrylamide 1.5 parts New Coal 707SF 4.2 parts Deionized water 25.0 parts

[Example 1]
Colloidal silica (II), organic solvent (III), alkali swelling type thickener (IV), nonionic surfactant (V), antifoaming to polymer (I) -1 obtained in Production Example 2 The agent was blended as shown in Table 1, and after stirring the disper, it was allowed to stand overnight to obtain an aqueous coating material.

[Examples 2 to 5, Comparative Examples 1 to 6]
Except for changing the polymer (I), colloidal silica (II), organic solvent (III), alkali swelling thickener (IV), nonionic surfactant (V), and antifoaming agent as shown in Table 1. Obtained an aqueous coating material in the same manner as in Example 1.

The abbreviations in Table 1 indicate the following compounds.
DPnB: Dipropylene glycol n-butyl ether DMFDG: Dimethylpropylene diglycol Butyl cellosolve: Ethylene glycol monobutyl ether Texanol: 2,2,4-trimethyl-1,3-pentadiol 1-isobutyrate

From the results of Table 1, the aqueous coating materials of Examples 1 to 5 of the present invention had excellent hydrophilicity, storage stability and high thixotropy.
On the other hand, Comparative Example 1 lacked colloidal silica (II) and was inferior in hydrophilicity.
In Comparative Example 2, colloidal silica (II) was excessive and storage stability was poor.
In Comparative Example 3, the organic solvent (III) having a solubility in 100 g of water of 2 g or more under the condition of 20 ° C. was lacking, and the storage stability was poor.
In Comparative Examples 4 and 5, the alkali swelling type thickener (IV) was lacking, and the storage stability or thixotropy was lacking.
In Comparative Example 6, the nonionic surfactant (V) was lacking and the hydrophilicity was poor.

Claims (4)

  Polymer (I), colloidal silica (II), organic solvent (III) having a solubility in 100 g of water at 20 ° C. of 2 g or more, alkali swelling thickener (IV), and nonion having an HLB of 16 or more An aqueous coating material containing a surfactant (V), wherein 0.1 to 18 parts by weight of colloidal silica (II) and nonionic surfactant (V) are added to 100 parts by weight of the polymer (I). ) In an amount of 0.01 to 10 parts by mass.   Polymer (I) is a hydrolyzable silyl group-containing radical polymerizable monomer and / or a monomer (a) having two or more radical polymerizable groups, a carboxyl group-containing radical polymerizable monomer (b), The aqueous coating material according to claim 1, obtained by polymerizing a radical polymerizable monomer mixture containing another monomer (c).   The aqueous coating material according to claim 1 or 2, further comprising an anionic surfactant.   The coating film obtained from the aqueous coating material in any one of Claims 1-3.