JP2007204678A - Water-based coating material - Google Patents

Abstract

[PROBLEMS] There is no bleeding out of the coating film of the deterioration preventing component and the rough surface of the coating film, and it is excellent in mechanical stability, pigment, resin beads and silica dispersibility, and the coating film has initial gloss, weather resistance, An aqueous coating material excellent in hot water resistance is provided.
SOLUTION: Specific ethylenically unsaturated monomer (a) unit 40 to 88 parts by mass, ethylenically unsaturated monomer (b) unit 6 to 40 parts by mass represented by general formula (I), general Emulsion particles (A) comprising 5 to 20 parts by mass of the ethylenically unsaturated monomer (c) unit represented by the formula (II) or (III) and 1 to 10 parts by mass of the specific reactive emulsifier (d) unit Aqueous coating material containing.
[Selection figure] None

Description

  The present invention relates to an aqueous coating material having excellent weather resistance.

In recent years, in the field of paints used for buildings and civil engineering structures, the shift from solvent-based paints that use organic solvents to water-based paints that use water as a dispersion medium has been attempted in consideration of the painting work environment. Yes. For this reason, the use of water-based paints has been expanded, and accordingly, performance requirements for water-based paints have become high. Among such required performances, it has been pointed out that it is important to improve the appearance, water resistance, weather resistance, etc. of the coating film.
Patent Document 1 discloses a technique for improving weather resistance by adding an ultraviolet absorber (hereinafter referred to as “UVA”) and a hindered phenol radical scavenger.
Patent Document 2 discloses that by copolymerizing a highly hydrophobic tertiary butyl group-containing polymerizable monomer, a small amount of a polymerizable UV-stable monomer, and a carboxyl group-containing ethylenically unsaturated monomer. Disclosed is a technique for obtaining excellent weather resistance over a long period of time without causing bleed-out from a coating film, which is excellent in mechanical stability and pigment dispersibility.
Patent Document 3 has excellent compatibility by localizing a hindered amine compound (hereinafter referred to as “HALS”) and a cycloalkyl group-containing silane coupling agent in the outermost layer of emulsion particles in a multistage emulsion polymerization method. A technique for obtaining a uniform coating film and a coating film having excellent long-term weather resistance is disclosed.

However, in patent document 1, since the said additive bleeds out from a coating film with time, it is difficult to maintain a weather resistance over a long period of time. Furthermore, since the additive is difficult to dissolve in water, which is the main medium of the water-based paint, in order to uniformly disperse the paint in the paint, a technique such as dispersing the additive in water using a dispersant or the like in advance. The manufacturing method is complicated. There was also a problem with the long-term stability of the manufactured paint.
In Patent Document 2, since a carboxyl group-containing ethylenically unsaturated monomer is contained as a constituent component, if an attempt is made to further copolymerize polymerizable HALS as a copolymerization component, the carboxyl group in the copolymer As a result, the emulsion polymerization becomes unstable, so the polymerization must be carried out using a large amount of non-reactive nonionic emulsifiers that cause a reduction in water resistance, and there is no response to increasing water resistance and warm water resistance. It was enough.
In Patent Document 3, polymerization is performed stably by polymerizing polymerizable HALS in the final stage, but the HALS copolymer layer is the outermost layer, and the layer containing a carboxyl group is the inner layer. The stability and initial gloss were lowered, and it was insufficient in terms of the response to the high design of advanced paints and the stability of paints.

  In recent years, in order to satisfy the demand for long-term weather resistance in the market, a water-based paint containing a silicone-based or fluorine-based resin as a component has been developed. In particular, it is known that gloss retention in an accelerated weather resistance test of a fluorine-based resin has a very excellent performance of 5000 hours or more. However, pigment dispersibility, painting workability, and recoatability at the time of renovation in a house are insufficient. In addition, as a countermeasure to the above-mentioned problem, for those in which an acrylic component and a silicone or fluorine component are hybridized, the gloss retention is good due to the effect of the silicone or fluorine component, but the molecular weight is lowered due to deterioration of the acrylic component. Since the strength and adhesion of the coating film are remarkably reduced as compared with the initial coating film, it is still insufficient in terms of long-term weather resistance.

JP-A-63-43972 JP 2001-49165 A JP 2004-10805 A

  The present invention does not cause bleed out from the coating film, hardly causes rough skin due to incompatibility between the deterioration preventing component and the resin component, and does not contain a carboxyl group that affects the piperidyl group. An object of the present invention is to provide an aqueous coating material that is excellent in properties, pigments, resin beads, and silica dispersibility, and in which the resulting coating film is excellent in initial gloss, weather resistance, and hot water resistance.

（Ｒ^３は水素原子又は炭素数１若しくは２のアルキル基、Ｘは酸素原子又はイミノ基、Ｙは水素原子又は炭素数１〜２０のアルキル基若しくはアルコキシ基、Ｚは水素原子又はシアノ基を示す。）

（Ｒ^４は水素原子又は炭素数１若しくは２のアルキル基、Ｒ^５は炭素数１〜１５の直鎖若しくは分岐した炭化水素置換基又は環状構造を持つ炭化水素置換基、Ｒ^６は炭素数１〜２５の直鎖若しくは分岐した炭化水素置換基又は環状構造を持つ炭化水素置換基。）

（Ｒ^７は水素原子又は炭素数１若しくは２のアルキル基、Ｒ^８は炭素数１〜１５の直鎖若しくは分岐した炭化水素置換基又は環状構造を持つ炭化水素置換基、Ｒ^９は炭素数１〜２５の直鎖若しくは分岐した炭化水素置換基又は環状構造を持つ炭化水素置換基。） The present _{invention, -COOH, -P (= O)} (OH) 2, -P (= O) ethylenically unsaturated monomer containing neither 2 OH and -SO ₄ H (a) units 40 to 88 6 parts by mass of ethylenically unsaturated monomer (b) unit having piperidyl group in the molecule represented by the following general formula (I), represented by the following general formula (II) or (III) Reactive emulsifier comprising 5 to 20 parts by mass of ethylenically unsaturated monomer (c) unit having an ultraviolet absorbing group in the molecule and an anionic reactive emulsifier having an unsaturated double bond capable of radical polymerization in the molecule (D) The aqueous coating material contains emulsion particles (A) containing 1 to 10 parts by mass of units (provided that the total of units (a), (b), (c) and (d) is 100 parts by mass)). In the following description, ethylenically unsaturated monomers (a), (b) and (c) are abbreviated as monomer (a), monomer (b) and monomer (c), respectively.

(R ³ is a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, X is an oxygen atom or imino group, Y is a hydrogen atom or an alkyl group or alkoxy group having 1 to 20 carbon atoms, and Z is a hydrogen atom or a cyano group. .)

(R ⁴ is a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, R ⁵ is a linear or branched hydrocarbon substituent having 1 to 15 carbon atoms or a hydrocarbon substituent having a cyclic structure, and R ⁶ is 1 carbon atom. ˜25 linear or branched hydrocarbon substituents or hydrocarbon substituents having a cyclic structure.)

(R ⁷ is a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, R ⁸ is a linear or branched hydrocarbon substituent having 1 to 15 carbon atoms or a hydrocarbon substituent having a cyclic structure, and R ⁹ is 1 carbon atom. ˜25 linear or branched hydrocarbon substituents or hydrocarbon substituents having a cyclic structure.)

  According to the present invention, bleed out from the coating film, almost no rough skin due to the incompatibility of the deterioration prevention component and the resin component, and no carboxyl group affecting piperidyl group, machine stability It is possible to provide an aqueous coating material that is excellent in properties, pigments, resin beads, and silica dispersibility, and in which the resulting coating film is excellent in initial gloss, weather resistance, and warm water resistance.

The monomer which is a raw material of the monomer (a) unit of the present invention contains all of —COOH, —P (═O) (OH) ₂ , —P (═O) ₂ OH and —SO ₄ H. do not do. Examples of such a monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl. (Meth) acrylate, sec-butyl (meth) acrylate, t-butyl acrylate, n-amyl (meth) acrylate, i-amyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, alkyl (meth) acrylates such as n-octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate; cyclohexyl (meth) Acryle And cycloalkyl (meth) acrylates such as pt-butylcyclohexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4 -Hydroxyl group-containing (meth) acrylates such as hydroxybutyl (meth) acrylate and glycerol mono (meth) acrylate; hydroxypolyethylene oxide mono (meth) acrylate, hydroxypolypropyleneoxide mono (meth) acrylate, hydroxy (polyethyleneoxide-polypropyleneoxide) ) Polyalkylene oxide group-containing (meth) such as mono (meth) acrylate and hydroxy (polyethylene oxide-propylene oxide) mono (meth) acrylate Acrylates; lactone-modified hydroxyalkyl (meth) acrylates; 2-aminoethyl (meth) acrylate, 2-dimethylaminoethyl (meth) acrylate, 2-aminopropyl (meth) acrylate, 2-butylaminoethyl (meth) acrylate Aminoalkyl (meth) acrylates such as; amide group-containing ethylenically unsaturated monomers such as (meth) acrylamide; dimethylaminoethyl (meth) acrylate methyl chloride salt, glycidyl (meth) acrylate, (meth) acrylonitrile, tetrahydro Other (meth) acrylate monomers such as furfuryl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate; styrene, methylstyrene, chlorostyrene, methoxystyrene Aromatic ethylenically unsaturated monomers such as 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene and the like conjugated diene monomers; vinyl acetate, vinyl chloride, ethylene, vinyl propionate, etc. Is mentioned. These are used alone or in combination of two or more.

  As the monomer (a), it is preferable to use (meth) acrylate alone or in combination of two or more from the viewpoint of the weather resistance of the coating film, in order to significantly suppress the decrease in the molecular weight of the emulsion particles (A). Particularly preferred are methacrylates. The expression “(meth) acrylate” means acrylate or methacrylate. The same applies to the expression “(meth) acryl or (meth) acrylo”. In addition, the monomer classified into the monomer (b) shown below shall not be contained in the monomer (a).

  The amount of the monomer (a) used is such that the monomer (a), monomer (b), monomer (c) and When the total amount of the reactive emulsifier (d) (hereinafter referred to as “total amount of monomers”) is 100 parts by mass, it is preferably 40 to 88 parts by mass. More preferably, it is 45-80 mass parts.

As the monomer that is a raw material for the monomer (b) unit, a monomer represented by the general formula (I) having a piperidyl group in the molecule is used. In the formula, Y is preferably a hydrogen atom, an alkyl group having 1 to 13 carbon atoms or an alkoxy group, and more preferably an alkyl group having 1 to 13 carbon atoms or an alkoxy group. In this case, the alkyl group or alkoxy group having 1 to 13 carbon atoms may be linear, branched, or form a cyclic structure. As a specific example of the monomer (b), one having mainly an ultraviolet light stabilizing function can be used. For example, 4- (meth) acryloxy 2,2,6,6-tetramethylpiperidine, 4- (Meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloxy 1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-1,2, Examples include 2,6,6-pentamethylpiperidine, 4-cyano-4- (meth) acryloxy 2,2,6,6-tetramethylpiperidine and the like. These can be used alone or in combination of two or more. From the viewpoint of the weather resistance of the coating film, it is particularly preferable to use, as the monomer (b), a methacrylate in which R ³ is a methyl group alone or in combination of two or more.

  The amount of the monomer (b) used is preferably 6 to 40 parts by mass with respect to 100 parts by mass of the total amount of monomers from the viewpoint of the weather resistance of the coating film and the dispersibility of the pigment, resin beads and silica. . By setting the monomer (b) to 6 parts by mass or more, the pigment dispersibility is improved, so that the resin beads can be easily dispersed and good color developability can be exhibited even in various pigment systems. Moreover, the weather resistance and recoatability of the coating film are improved. Moreover, the weather resistance of a coating film can further be improved by making it 40 mass parts or less, without reducing superposition | polymerization stability. From the viewpoint of high pigment dispersibility and weather resistance, the amount is more preferably 10 to 40 parts by mass.

  As the monomer which is a raw material of the monomer (c) unit, a monomer represented by the general formula (II) or (III) having an ultraviolet absorbing group in the molecule is used. Specific examples include 2- (2′-hydroxy-5 ′-(meth) acryloxyethylphenyl) -2H-benzotriazole, 2- (2′-hydroxy-3′-tertiary butyl-5 ′-( And (meth) acryloxyethylphenyl) -2H-benzotriazole, 2- (2′-hydroxy-3′-tertiary amyl-5 ′-(meth) acryloxyethylphenyl) -2H-benzotriazole, and the like. These can be used alone or in combination of two or more.

  The usage-amount of a monomer (c) is 5-20 mass parts with respect to 100 mass parts of monomer total amounts from the point of the weather resistance of a coating film, the fading prevention of a foundation | substrate, and the dispersibility of a resin bead and a silica. Is preferred. By setting the monomer (c) to 5 parts by mass or more, the dispersibility of the resin beads and silica can be improved, and aggregation at the time of adding a matting agent can be avoided. The prevention ability is also improved. Moreover, the weather resistance of a coating film can further be improved, without reducing polymerization stability as it is 20 mass parts or less. More preferably, it is 10-20 mass parts.

  As the reactive emulsifier (d) which is a raw material of the reactive emulsifier (d) unit, one containing an anionic reactive emulsifier having an unsaturated double bond capable of radical polymerization in the molecule is used. For example, a reactive emulsifier having an allyl group in the molecule as a reaction site can be used. Specifically, Adeka Soap SR-10, SE-10 (trade name) manufactured by Asahi Denka Co., Ltd., Aqualon KH-05, KH-10, HS-10 (trade name) manufactured by Daiichi Kogyo Seiyaku Co., Ltd., etc. . Further, examples of the anionic reactive emulsifier having a reactive group other than an allyl group as a reactive site include Latem PD-104 (trade name) manufactured by Kao Corporation.

  In applications where high mechanical stability is required, it is preferable to use a nonionic reactive emulsifier having an unsaturated double bond capable of radical polymerization in the molecule. The ratio at this time is particularly preferably anionic reactive emulsifier: nonionic reactive emulsifier of 8: 2 to 2: 8 (mass ratio).

Nonionic reactive emulsifiers include, for example, Adeka Soap NE-10, ER-10, NE-20, ER-20, NE-30, ER-30, NE-40, ER-40 manufactured by Asahi Denka Co., Ltd. Name), Aqualon RN-10, RN-20, RN-30, RN-50 (above trade names) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. and the like.
The anionic reactive emulsifier and the nonionic reactive emulsifier can be used alone or in combination of two or more.
The amount of the reactive emulsifier (d) used depends on the polymerization stability during the production of the emulsion particles (A), the mechanical stability of the emulsion particles (A) and the water resistance, warm water resistance and weather resistance of the coating film. From the point, it is preferable to set it as 1-10 mass parts with respect to 100 mass parts of monomer total amount. By setting the reactive emulsifier (d) to 1 part by mass or more, polymerization stability and mechanical stability are improved. Moreover, a weather resistance can further be improved by making it 10 mass parts or less, without reducing the water resistance of a coating film. More preferably, it is 1-8 mass parts.

The average particle size of the emulsion particles (A) of the present invention is preferably 50 nm to 300 nm in consideration of the balance between the stability of the particles and the coating film performance. 50 nm or more is preferable at the point of the polymerization stability at the time of emulsion particle | grains (A) manufacture, and the water resistance of the coating film obtained. Moreover, 300 nm or less is preferable at the point of the particle dispersibility of emulsion particle | grains (A), and the water resistance of a coating film.
In the present invention, the glass transition temperature (hereinafter referred to as “Tg”) of the emulsion particles (A) is preferably 100 ° C. or less from the viewpoint of the film forming property of the coating film, and particularly from the viewpoint of the flexibility of the coating film. Preferably it is 70 degrees C or less. Moreover, it is preferably −30 ° C. or higher from the viewpoint of contamination.
In addition, as said Tg, the calculated glass transition temperature calculated | required by the formula of Fox is used. The Fox formula is a relational expression between the glass transition temperature (° C.) of the homopolymer obtained by homopolymerizing each of the copolymerization monomers and the glass transition temperature (° C.) of the copolymer as shown below. .
1 / (273 + Tg) = Σ (W _i / (273 + Tg _i ))
In the formula, W _i represents the mass fraction of monomer i, and Tg _i represents Tg (° C.) of the homopolymer of monomer i.
In addition, as Tg of a homopolymer, the value specifically described in "Polymer Handbook 3rd Edition" (A WILEY-INTERSCIENCE PUBLICATION, 1989) can be used.

In the present invention, the emulsion particles (A) can be produced by a usual emulsion polymerization method. Usually, the polymer / water ratio of emulsion polymerization is 20/80 to 80/20.
In the case of adjusting the molecular weight of the resulting copolymer, 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 can be used. In order not to lower the weather resistance, the amount of chain transfer agent used is preferably 0.5% by mass or less, more preferably not used, based on the total amount of monomers.

  In addition, in the case where control of the particle size or mechanical stability at a particularly high level is required, it is possible to use a non-reactive surfactant in addition to the reactive emulsifier (d). The amount is preferably 3 parts by mass or less with respect to 100 parts by mass of the total amount of monomers from the viewpoint of water resistance. By setting the non-reactive surfactant to 3 parts by mass or less, the mechanical stability and temporal stability of the emulsion (A) can be further improved without impairing water resistance. Examples of the surfactant include various known anionic or nonionic surfactants, and polymer emulsifiers.

As the polymerization initiator for carrying out emulsion polymerization, those generally used for radical polymerization can be used. Specific examples include 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), oil-soluble azo compounds such as 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, 2,2′-azobis {2-methyl-N- [2 -(1-hydroxyethyl)] propionamide}, 2,2′-azobis {2-methyl-N- [2- (1-hydroxybutyl)] propionamide}, 2,2′-a Bis [2- (5-methyl-2-imidazolin-2-yl) propane] and salts thereof, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] and salts thereof, 2,2 '-Azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] and its salts, 2,2'-azobis {2- [1- (2-hydroxyethyl) -2-imidazoline -2-yl] propane} and its salts, 2,2'-azobis (2-methylpropionamidine) and its salts 2,2'-azobis (2-methylpropyneamidine) and its salts, 2,2'- Water-soluble azo compounds such as azobis [N- (2-carboxyethyl) -2-methylpropionamidine] and salts thereof; benzoyl peroxide, cumene hydroperoxide, t-butyl hydroper And organic peroxides such as oxide, t-butylperoxy-2-ethylhexanoate, and t-butylperoxyisobutyrate. A polymerization initiator can be used individually or in combination of 2 or more types. When acceleration of the polymerization rate and polymerization at a low temperature of 70 ° C. or lower are desired, for example, a combination of a reducing agent such as sodium bisulfite, ferrous sulfate and ascorbate and a radical polymerization catalyst is used.
The amount of the polymerization initiator used is preferably in the range of 0.01 to 10% by mass with respect to the total amount of monomers, but 0.05 to 5% by mass in consideration of the progress of polymerization and control of the reaction. It is more preferable to set the range.

  The emulsion particles (A) used in the aqueous coating material of the present invention can be prepared by, for example, pre-emulsifying with a monomer component and water in an aqueous medium, and emulsion polymerization using a radical polymerization initiator. it can. The polymerization of the emulsion particles (A) may be batch polymerization (single layer structure) or multi-stage polymerization (multi-layer structure), but in the case of multi-stage polymerization, it should be 3 stage polymerization or less from the viewpoint of production efficiency. Is preferred.

  The emulsion obtained by the emulsion polymerization method can increase the stability of the system after the polymerization by adjusting the pH of the system to be weakly alkaline, that is, in the range of about pH 7.5 to 10.0 by adding a basic compound. . Moreover, it is more preferable to adjust the pH of the system to about 7.5 to 10.0 before the start of polymerization because the cullet can be further reduced. Examples of basic compounds for adjusting pH 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, ethoxypropylamine, aminobenzyl alcohol, morpholine, sodium hydroxide, potassium hydroxide and the like. In the case of interior use where it is desired not to contain a volatile organic compound (VOC), an inorganic basic compound is preferably used. Further, when it is desired that there is no slight odor, it is preferable to use a non-volatile inorganic basic compound such as sodium hydroxide or potassium hydroxide.

The solid content of the aqueous coating material of the present invention is usually 20 to 80% by mass. In addition, various pigments, antifoaming agents, pigment dispersants, leveling agents, anti-sagging agents, matting agents, antioxidants, heat resistance improvers, slip agents, preservatives are used to develop advanced performance as coating materials. May be included. Furthermore, you may mix and use hardening agents, such as another emulsion resin, water-soluble resin, a viscosity control agent, and melamines.
In order to form a coating film on the surface of various materials using the aqueous coating material of the present invention, for example, spray coating method, roller coating method, bar coating method, air knife coating method, brush coating method, dipping method, etc. The coating method may be selected as appropriate. Moreover, the aqueous coating material of this invention can obtain the coating film which formed the film sufficiently in room temperature drying by adding the film-forming auxiliary | assistance of single or a required amount.

Colloidal silica can be added to the aqueous coating material of the present invention for the purpose of improving antifouling properties. As for the addition amount (solid content) of colloidal silica, 0.5-20 mass parts is preferable with respect to 100 mass parts of solid content of an emulsion particle (A). When the content is 0.5 parts by mass or more, the stain resistance of the coating film is improved. On the other hand, the contamination resistance, antistatic property, and water contact angle of the coating film can be further improved without reducing the transparency, weather resistance, water resistance, and frost damage resistance of the coating film at 20 parts by mass or less. A more preferable content is 1 to 18 parts by mass.
The average particle size of the colloidal silica used in the present invention is 1 to 60 nm, preferably 40 nm or less, more preferably 20 nm or less.
As the colloidal silica, a commercially available product can be used, which may be one using water as a dispersion medium or one using an organic solvent as a dispersion medium. Examples of the water-based dispersion medium include acidic aqueous colloidal silica, alkaline aqueous colloidal silica, and cationic colloidal silica.
Examples of the aqueous colloidal silica exhibiting acidity include trade names: Snowtex OXS and Snowtex OS (manufactured by Nissan Chemical Industries, Ltd.). Examples of the aqueous colloidal silica exhibiting alkalinity include, for example, trade name: Snowtex. XS, Snowtex 20 (manufactured by Nissan Chemical Industries, Ltd.) and the like.
Examples of the cationic colloidal silica include Snowtex AK (Nissan Chemical Industry Co., Ltd., SiO2 solid content 19%), Silica Doll-20P (Nihon Chemical Industry Co., Ltd., SiO2 solid content 20%) and the like. It is done. These colloidal silicas can be used alone or in combination of two or more.
Moreover, colloidal silica surface-treated with a silane compound can also be used.

  Hereinafter, the present invention will be described in more detail with reference to examples. In the following description, “part” is based on mass. The coating film was evaluated according to the following test method after preparing a paint with the following composition.

<Manufacture of matte clear paint>
Add CS-12 (trade name, manufactured by Chisso Corporation, film-forming aid) to 100 g of aqueous coating material until the minimum film-forming temperature (hereinafter referred to as “MFT”) reaches 5 ° C. Name, 10% manufactured by Kaleido Co., Ltd., silica-based matting agent, 0.5 g RHEOLATE350 (trade name, manufactured by RHEOX Co., Ltd., thickener), Surfynol DF-58 (trade name, Air Products Co., Ltd.) Product, antifoaming agent) 0.5 g was added, and the mixture was sufficiently stirred and filtered using a 100 mesh nylon candy to obtain a matte clear paint for evaluation. In addition, MFT was measured based on the test method JIS K6828 of the synthetic resin emulsion.

<Manufacture of white enamel paint>
TYPEQUE CR-97 (trade name, manufactured by Ishihara Sangyo Co., Ltd., chlorinated titanium oxide) 707 g, Adeka Coal W-193 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd., pigment dispersant), Surfynol DF-58 ( Product name, Air Products Co., Ltd., defoaming agent) 25 g, deionized water 256 g are mixed well, glass beads are added, and pigment dispersion is performed for 30 minutes with a high-speed disperser, and then glass beads are 300 mesh The product was filtered with a nylon basket to obtain an evaluation mill base (solid content: 71% by mass).
Next, with respect to 100 g of aqueous coating material (based on solid content of 46% by mass), CS-12 is added until the MFT reaches 5 ° C., 42.7 g of the evaluation mill base, RHEOLATE 350, and 0.5 g are added in that order. Stir well and adjust with Ford cup # 4 by adding deionized water to about 30 seconds. Thereafter, filtration was again performed using a 300 mesh nylon candy to obtain a white enamel paint for evaluation having a pigment weight concentration (PWC) of 40%.

<Test method>
(1) Weather resistance test Spray coating was performed on the zinc phosphate-treated steel plate (bonderite # 100-treated steel plate, thickness 0.8 mm, 70 mm × 150 mm) so that the dry film thickness was 50 μm. Thereafter, the plate was left to stand at room temperature for 1 hour and forcibly dried at 80 ° C. for 1 hour to obtain a coated plate for weather resistance evaluation. This coated plate is cut into a size of 70 mm × 50 mm, and this test plate is put into a die plastic metal weather KU-R4-W type (manufactured by Daipura Wintes Co., Ltd.). Test cycle: irradiation 4 hours / condensation 4 hours, UV Strength: 85 mW / cm ² , black panel temperature: 63 ° C. during irradiation / 30 ° C. during condensation, humidity: 50% RH during irradiation / 96% RH during condensation The retention rate was used as an indicator of the weather resistance of the coating film, and the determination was made according to the following criteria. The 60 ° gloss was measured using a modified gloss meter VG-2000 manufactured by Nippon Denshoku Industries Co., Ltd.
A: 90% or more.
○: 75% or more and less than 90%.
○ △: 60% or more and less than 75%.
Δ: 40% or more and less than 60%.
X: Less than 40%.

(2) Base fading prevention test The same zinc phosphate-treated steel plate as described above has an odorless big 10 gloss made by Asahi Pen Co., Ltd. as a colored base and is spray-coated with an outdoor blue paint to a dry film thickness of 50 μm. Then, it was left at room temperature for 1 hour and forcedly dried at 80 ° C. for 1 hour. Subsequently, the matte clear paint was spray-coated so as to have a dry film thickness of 30 μm, then allowed to stand at room temperature for 1 hour, and forcedly dried at 80 ° C. for 1 hour to obtain a coated plate for a background fading prevention test. This coated plate is cut into a size of 70 mm × 50 mm, and this test plate is put into a die plastic metal weatherer KU-R4-W type. Under the same conditions as described above, ΔE of the coated film after 3000 hours has been faded. It was determined according to the following criteria as an index of prevention ability. ΔE was measured using a spectrocolor meter SE-2000 manufactured by Nippon Denshoku Industries Co., Ltd.
◎: 1 or less.
○: More than 1: 3 or less.
Δ: More than 3 and 5 or less.
X: More than 5.

(3) Pigment dispersibility A white enamel paint for evaluation was spray-coated on a zinc phosphate-treated steel plate similar to the above to a dry film thickness of 50 μm, then left at room temperature for 1 hour and forced at 80 ° C. for 1 hour. The dried product was used as a coating plate for evaluating pigment dispersibility. The 60 ° gloss value of the coating film of this test plate was used as an index of pigment dispersibility in the coating film, and the following criteria were used for the determination. The 60 ° gloss was measured using a modified gloss meter VG-2000 manufactured by Nippon Denshoku Industries Co., Ltd.
A: 85 or more.
○: 80 or more and less than 85.
Δ: 70 or more and less than 80
X: Less than 70.

(4) Appearance of coating film A test plate for coating film appearance was prepared by applying an emulsion on a glass plate (15 cm × 15 cm) using an 8MIL applicator and then forcibly drying at 80 ° C. for 1 hour. The 20 ° gloss value of the coating film of this test plate and the degree of rough skin were judged by visual evaluation based on the following criteria.
A: 20 ° gloss value is 80 or more, and no rough coating is observed.
○: 20 ° gloss value of 60 or more and less than 80.
Δ: 20 ° gloss value of 40 or more and less than 60, coating film roughening or slight coating haze is observed.
X: 20 degree gloss value is less than 40, and remarkable skin roughening or coating film haze is observed.

(5) Silica dispersibility test The same zinc phosphate-treated steel plate as above was spray-coated with a matte clear paint for evaluation so that the dry film thickness was 30 μm, then left at room temperature for 1 hour, and then at 80 ° C. for 1 hour. What was forcibly dried was used as a coated plate for silica dispersibility evaluation. The value of 20 ° gloss of the coating film of this test plate was used as an index and judged according to the following criteria. The 20 ° gloss was measured using a modified gloss meter VG-2000 manufactured by Nippon Denshoku Industries Co., Ltd.
○: 2 or less.
Δ: More than 2 and 5 or less.
X: More than 5.

(6) Warm water resistance test A clear paint was applied on a glass plate similar to the above using an 8MIL applicator, then dried at room temperature for 1 hour, and then forced dried at 80 ° C for 1 hour. A coated plate for evaluation was used. The evaluation coated plate was immersed in water at 60 ° C. for 1 week. The presence or absence of blistering and blistering immediately after removal of the coating film was confirmed and judged according to the following criteria.
A: No change is observed at all.
○: Slightly bluish, but no swelling or peeling.
Δ: Whitening is observed, but no swelling or peeling is observed.
X: Significant whitening and swelling or peeling are observed.

(7) Mechanical stability test 100g of water-based coating material was tested for 10 minutes with a Malone tester over a 15kg share, filtered through a 100 mesh nylon bottle, and the amount of the residue was measured. I evaluated it.
A: 0.01 g or less.
○: More than 0.01 g and 0.1 g or less.
(Triangle | delta): More than 0.1 and 0.5 g or less.
X: More than 0.5 g or gelation during the test.

(8) Storage stability 200 g of the aqueous coating material is placed in a 225 cc mayonnaise bottle and placed in a constant temperature water bath at 50 ° C. for one week. Thereafter, the product was taken out, the presence / absence of a coagulated product and the viscosity were confirmed, and evaluated according to the following criteria.
○: There is no coagulum, and the rate of change in viscosity is ± 20% or less.
(Circle) (triangle | delta): There is no solidified substance and the change rate of a viscosity is more than +/- 20% and less than +/- 30%.
Δ: There is no coagulum, and the rate of change in viscosity is more than ± 30%.
X: A solidified substance is observed.

(9) Polymerization stability The cullet during polymerization in Examples 1 to 8 and Comparative Examples 1 to 5 was collected by filtration with a 100 mesh nylon basket, dried in a drying oven at 50 ° C. for 24 hours, and its weight was measured. And evaluated according to the following criteria.
A: The amount of cullet in the dry state is 100 ppm or less.
○: The amount of cullet in the dry state is more than 100 ppm and 1000 ppm or less.
Δ: The amount of cullet in the dry state exceeds 1000 ppm, but can be polymerized.
X: Polymerization is impossible.

Example 1
In a flask equipped with a stirrer, a reflux condenser, a temperature controller, a dropping pump, and a nitrogen introduction tube, 45 parts of deionized water, 5 parts of Emulsion A and a 25% aqueous ammonia solution in a proportion shown in Table 1 were added. 5 parts were charged and the temperature was raised to 75 ° C. while replacing the inside of the flask with nitrogen. Thereafter, an initiator solution in which 0.1 part of ammonium persulfate (polymerization initiator) was dissolved in 1 part of water was added to initiate polymerization, and an exothermic peak was confirmed to obtain seed particles. Subsequently, at an internal temperature of 75 ° C., an initiator solution obtained by dissolving 0.2 part of ammonium persulfate (polymerization initiator) in 3 parts of water and the rest of the emulsion A were dropped over 4 hours. Furthermore, the remaining emulsion A was polymerized by aging for 2 hours at an internal temperature of 75 ° C. to obtain emulsion particles (A). Thereafter, the mixture was cooled, neutralized with ammonia at a temperature of 40 ° C. or lower, and then taken out from the flask to obtain an aqueous coating material. The obtained aqueous coating material was subjected to polymerization stability evaluation, mechanical stability test, and storage stability test, and the results shown in Table 1 were obtained. In addition, a weather resistance test and a pigment dispersibility test were conducted on the coating film obtained using the white enamel paint, and a hot water resistance test was conducted on the coating film obtained using the clear paint, and the results shown in Table 2 were obtained. .

(Examples 2 to 8)
In the same manner as in Example 1, an emulsion having the composition shown in Table 1 was produced to obtain an aqueous coating material, and various characteristic values shown in Table 1 were obtained. Moreover, various coating film tests after coating were performed, and the results shown in Table 2 were obtained.
The solid content (NV), viscosity, and average particle diameter of the emulsion particles (A) of the obtained aqueous coating material were measured by the following method.
NV was obtained by drying the aqueous coating material at 105 ° C. for 2 hours and determining the weight before and after drying.
The viscosity was measured with an R-100 viscometer manufactured by Toki Sangyo Co., Ltd. with the temperature of the aqueous coating material set to 25 ° C.
The average particle size was measured at 25 ° C. using a concentrated analyzer FPAR-1000 manufactured by Otsuka Electronics Co., Ltd., and the average particle size obtained by cumulant analysis was obtained.
As is apparent from Table 2, the aqueous coating material of this example is excellent in weather resistance and warm water resistance, and is excellent in pigment dispersibility, mechanical stability, storage stability and polymerization stability.

(Comparative Examples 1-3)
In the same manner as in Example 1, an emulsion having the composition shown in Table 1 was produced to obtain an aqueous coating material, and various characteristic values shown in Table 1 were obtained. In Comparative Example 3, the polymerization was stopped because a solidified product was formed 10 minutes after the start of the polymerization dropping and stirring became difficult. Moreover, various coating film tests after coating were performed, and the results shown in Table 2 were obtained.
As is clear from Table 2, Comparative Example 1 has poor hot water resistance and storage stability, and Comparative Example 2 has insufficient performance such as pigment dispersibility and silica dispersibility.

(Comparative Examples 4 and 5)
In the same manner as in Example 1, emulsions having the compositions shown in Table 1 were produced. After the neutralization treatment, a 50% butyl cellosolve solution of Tinuvin 292, which is a non-reactive type UV stabilizer, was added to obtain an aqueous coating material, and various characteristic values shown in Table 1 were obtained. Moreover, various coating film tests after coating were performed, and the results shown in Table 2 were obtained.
As is apparent from Table 2, Comparative Examples 4 and 5 in which the ethylenically unsaturated monomer (b) having a piperidyl group in the molecule is not copolymerized have insufficient weather resistance.

ＭＭＡ：メチルメタクリレート
ｎ−ＢＭＡ：ノルマルブチルメタクリレート
２−ＥＨＡ：２−エチルヘキシルアクリレート
２−ＨＥＭＡ：２−ヒドロキシエチルメタクリレート
ＡＡ：アクリル酸
Ｒ−ＵＶＡ９３：反応性紫外線吸収剤（商品名、大塚化学（株）製）

アデカリアソープＳＲ−１０：反応性アニオン性界面活性剤（商品名、旭電化（株）製）
アクアロンＨＳ−１０：反応性アニオン性界面活性剤（商品名、第一工業製薬（株）製）
アデカリアソープＥＲ−３０：反応性ノニオン性界面活性剤（商品名、旭電化（株）製）
アデカリアソープＥＲ−４０：反応性ノニオン性界面活性剤（商品名、旭電化（株）製）
Ｔｉｎｕｖｉｎ１１３０：非反応性紫外線吸収剤（チバ・スペシャリティ・ケミカルズ（株）製）
リボノックスＮＣ−３００：非反応性ノニオン性界面活性剤（商品名、ライオン（株）製）
ラテムルＥ−１１８Ｂ：非反応性アニオン性界面活性剤（商品名、花王（株）製）
Ｔｉｎｕｖｉｎ２９２：非反応性紫外線吸収剤（チバ・スペシャリティ・ケミカルズ（株）製）

MMA: methyl methacrylate n-BMA: normal butyl methacrylate 2-EHA: 2-ethylhexyl acrylate 2-HEMA: 2-hydroxyethyl methacrylate AA: acrylic acid R-UVA93: reactive ultraviolet absorber (trade name, Otsuka Chemical Co., Ltd.) Made)

ADEKA rear soap SR-10: Reactive anionic surfactant (trade name, manufactured by Asahi Denka Co., Ltd.)
Aqualon HS-10: Reactive anionic surfactant (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
ADEKA rear soap ER-30: Reactive nonionic surfactant (trade name, manufactured by Asahi Denka Co., Ltd.)
ADEKA rear soap ER-40: Reactive nonionic surfactant (trade name, manufactured by Asahi Denka Co., Ltd.)
Tinuvin 1130: Non-reactive UV absorber (Ciba Specialty Chemicals)
Ribonox NC-300: Non-reactive nonionic surfactant (trade name, manufactured by Lion Corporation)
Laterum E-118B: Non-reactive anionic surfactant (trade name, manufactured by Kao Corporation)
Tinuvin 292: Non-reactive UV absorber (Ciba Specialty Chemicals)

  The aqueous coating material of the present invention is made of various materials such as cement mortar, slate board, gypsum board, extruded board, foamable concrete, metal, glass, porcelain tile, asphalt, wood, waterproof rubber material, plastic, calcium silicate base material, etc. It can be used for the surface finishing of steel and is extremely useful in industry.

Claims (1)

_{-COOH, -P (= O) (} OH) 2, -P (= O) ethylenically unsaturated monomer containing neither 2 OH and -SO ₄ H (a) units 40 to 88 parts by weight, the following In the molecule represented by the following general formula (II) or (III), 6 to 40 parts by mass of the ethylenically unsaturated monomer (b) unit having a piperidyl group in the molecule represented by the general formula (I) Reactive emulsifier (d) unit comprising 5 to 20 parts by mass of ethylenically unsaturated monomer (c) unit having an ultraviolet absorbing group and an anionic reactive emulsifier having an unsaturated double bond capable of radical polymerization in the molecule An aqueous coating material containing emulsion particles (A) containing 1 to 10 parts by mass (however, the total of units (a), (b), (c) and (d) is 100 parts by mass)).

(R ³ is a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, X is an oxygen atom or imino group, Y is a hydrogen atom or an alkyl group or alkoxy group having 1 to 20 carbon atoms, and Z is a hydrogen atom or a cyano group. .)

(R ⁴ is a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, R ⁵ is a linear or branched hydrocarbon substituent having 1 to 15 carbon atoms or a hydrocarbon substituent having a cyclic structure, and R ⁶ is 1 carbon atom. ˜25 linear or branched hydrocarbon substituents or hydrocarbon substituents having a cyclic structure.)

(R ⁷ is a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, R ⁸ is a linear or branched hydrocarbon substituent having 1 to 15 carbon atoms or a hydrocarbon substituent having a cyclic structure, and R ⁹ is 1 carbon atom. ˜25 linear or branched hydrocarbon substituents or hydrocarbon substituents having a cyclic structure.)