JP2002206067A - Room temperature-curing water emulsion coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a room temperature-curing water emulsion coating having a low content of volatile organic compounds (VOC), excellent freezing-thawing stability and further excellent low-temperature film-forming properties, water and blocking resistances, etc., and capable of forming a film without causing bleedout of a pollutant. SOLUTION: This room temperature curing water emulsion coating comprises the following components: (A) emulsion resin particles comprising a copolymer containing (a) a lactone-modified acetoacetoxy(meth)acrylate monomer, (b) a carboxy group-holding ethylenically unsaturated monomer and (c) an ethylenically unsaturated monomer having at least either one of a polyethylene glycol chain and a polypropylene glycol chain as constituent components and (B) a pigment. In the copolymer, (1) the molar ratio [(a)/(b)] of the monomer (a) to the monomer (b) is 0.1-10 and the total amount of the monomer (a) and the monomer (b) is 0.5-60 mass% based on the whole monomers, the amount of the monomer (c) is 1-20 mass% and the other copolymerizable ethylenically unsaturated monomers (d) are the balance and (2) the minimum film-forming temperature of the emulsion resin particles is <=10 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a low-temperature film-forming property, a freeze-thaw stability, and a volatile organic compound (hereinafter referred to as "VOC"). It has excellent water resistance and blocking resistance, as well as harmful substances floating in the atmosphere such as formalin and toluene,
Even if a pigment that adsorbs and deodorizes to pollutants such as tobacco tar, soot, oil smoke, hand stains, and stains from rain leaks, it can adsorb and deodorize these substances without deteriorating storage stability. Also, the present invention relates to an aqueous emulsion paint capable of forming a coating film without exuding the contaminant even if it is directly applied to an indoor wall, ceiling or the like contaminated with the contaminant.

[0002]

2. Description of the Related Art In recent years, environmental regulations regarding reduction of VOCs and harmful substances have become strict, and from the viewpoint of resource saving, the paint industry has switched from a paint using an organic solvent to a paint using water as a solvent. Is being made. Especially, in buildings, general houses, vehicles, etc., the confidentiality has been increased due to the improvement of construction technology and the like. Is often used. However, since the aqueous emulsion paint uses water as a dispersion medium, it changes to a dispersed state during storage, particularly during a freeze-thaw cycle in winter, and increases in viscosity and, in severe cases, coagulates. There is a problem that freeze-thaw stability is poor. Therefore, conventionally, a method for improving the freeze-thaw stability by using an organic solvent such as ethylene glycol which is an antifreezing agent has been generally used.

[0003] A water-based emulsion paint has a unique minimum film forming temperature (hereinafter, referred to as MFT). When the temperature of the surface to be coated is lower than MFT, an organic solvent is used as a film forming aid for film formation. It was necessary to mix a solvent. Therefore, even if it is a water-based emulsion paint, it contains a considerable amount of VOC, and when the coating film is not sufficiently dried, there is a problem that water resistance and blocking resistance are deteriorated due to the remaining VOC. Further, in a room such as a building, a general house, and a vehicle, sources of VOCs and harmful substances are emitted not only from paints but also from furniture, adhesives at joints of building materials, and the like. Furthermore, when it is time to repaint, those interior surfaces are often contaminated with cigarette tar, soot, grease, oily smoke, rain stains, etc. There is a problem that contaminants often seep out before the film dries. In particular, since pollutants such as cigarette tar include a large amount of water-soluble components, when the aqueous anionic emulsion paint is applied at the time of repainting, seepage of the contaminants becomes remarkable. Therefore, when finishing to white or pale color, it is difficult to use the water-based paint, so use the organic solvent-based paint unavoidably, or pre-paint the water-based cationic sealer, and then use the water-based anionic emulsion paint. It becomes necessary to apply a top coat. Therefore, in the former, there is a problem from the viewpoint of environment and resource saving, in the latter, the painting process increases,
It was disadvantageous in terms of painting workability and cost.

Further, hydrotalcites disclosed in JP-A-5-59304, JP-A-5-59305, JP-A-6-207124, JP-A-6-207125, etc., and activated alumina On the other hand, an aqueous emulsion paint containing activated clay (these are adsorptive pigments) as a pigment component had poor storage stability. Japanese Patent Application Laid-Open No. 11-35848 discloses an aqueous emulsion paint having good long-term storage stability even if it contains an adsorbent pigment, but the low-temperature film formability of the emulsion resin itself is insufficient. Yes, a considerable amount of VOC such as a film forming aid and an antifreezing agent was required.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and does not require the use of VOCs or, even if used, with a small amount of addition.
Excellent low-temperature film-forming properties, freeze-thaw stability, water resistance, and blocking resistance. In addition, it absorbs harmful substances such as VOC in the air, formalin, etc., as well as tobacco tar, soot, and oil smoke. Providing a water-based emulsion paint that has the function of purifying the air and deodorizing by blending certain pigments and that can form a coating film without exuding water-soluble contaminants on the coating film surface The purpose is to do.

[0006]

Means for Solving the Problems The present invention has been intensively studied in order to solve the above-mentioned problems, and as a result, it has been found that the above-mentioned problems can be surely achieved by the following constitutions. is there. That is, the present invention relates to (A)
(A) a lactone-modified acetoacetoxy (meth) acrylate monomer, (b) an ethylenically unsaturated monomer having a carboxyl group, and (c) an ethylenically unsaturated monomer having at least one of a polyethylene glycol chain and a polypropylene glycol chain. Resin particles comprising a copolymer containing a monomer as a constituent component, and (B) a pigment,
A room temperature curable emulsion paint containing

(1) In the copolymer, the molar ratio of the monomer (a) to the monomer (b) [(a) / (b)] is as follows:
0.1 to 10, and among all monomers, monomer (a)
And the total amount of the monomer (b) is 0.5 to 60% by mass, the amount of the monomer (c) is 1 to 20% by mass, and Saturated monomer (d)
(2) a minimum film-forming temperature of the emulsion resin particles is 10 ° C. or lower.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The cold-curable aqueous emulsion paint of the present invention contains, as essential components, emulsion resin particles (A) and a pigment (B) serving as a binder, which are produced by emulsion polymerization of an ethylenically unsaturated monomer described below in water. Paint. The emulsion resin particles (A) used in the present invention include (a) a caprolactone-modified acetoacetoxy (meth) acrylate monomer, (b) a carboxyl group-containing ethylenically unsaturated monomer, (c) a polyethylene glycol chain and polypropylene. It is a copolymer obtained by emulsion polymerization of an ethylenically unsaturated monomer having at least one glycol chain and (d) another copolymerizable ethylenically unsaturated monomer.

The monomer (a) is preferably represented by the following formula:
(I), CH ₂ ＣC (R) —C (＝ O) O—CH ₂ CH ₂ —O—
[C (= O) - ( CH 2) m O-] n C (= O) CH 2 C
(＝ O) CH ₃ (wherein R is a hydrogen atom or a methyl group, and m is 5
An integer of from 7 to 7, preferably 5, and n is 1 or 2. )). This monomer is, for example, an acrylic vinyl monomer having a hydroxyl group at the terminal, for example, by reacting lactones such as caprolactone, to extend the ester bond,
It can be produced by reacting a free hydroxyl group present at the terminal of the obtained lactone-modified monomer with a carboxyl group of a compound containing a carboxyl group.
Examples of commercially available products of such monomers include, for example, “Placcel ATFA1” (trade name, manufactured by Daicel Chemical Industries, Ltd.),
“Placcel ATFA2”, “Placcel ATFM”
1 "," Placcel ATFM2 "and the like. Representative examples of the monomer (b) include (meth) acrylic acid, crotonic acid, itaconic acid, itaconic acid half ester, maleic acid, and maleic acid half ester.

The monomer (c) is represented by the following formula (II) or (II)
It is a monomer represented by I) or (IV). Formula (II): CH ₂ ＣC (R ¹ ) —C (＝ O) —O— [X—O] _n —R ² (wherein R ¹ is a hydrogen atom or a methyl group, and R ² is ,
X is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms;
— (CH ₂ ) ₂ — or —CH ₂ CH (CH ₃ ) — or a mixture thereof, and n is an integer of 1 to 30. ) Formula (III): CH ₂ ＣC (R ¹ )-(CH ₂ ) _m —O— [X—O] _n —R ² (where R ¹ , R ² , X and n represent the above formula ( III) It has the same meaning as in II), and m is an integer of 1 to 30.)

Formula (IV): CH ₂ ＣＲCR ¹ —C (＝ O) —O— (CH ₂ CH ₂ O) _m —
[CH ₂ —CH (CH ₃ ) —O] _n —R ² (wherein R ¹ and R ² have the same meanings as in the above formula (II), and m and n are integers of 1 to 30) The monomer (c) represented by these formulas is, for example, (meth)
It can be produced by subjecting ethylene oxide and / or propylene oxide to addition polymerization reaction with acrylic acid, allyl alcohol, or the like, and then, if necessary, etherifying with an alkyl group having 1 to 8 carbon atoms. Commercially available products of such monomers include, for example, trade names “MA-30”, “MA-50”, “MA-100”, “MA
-150 "," MPG-130MA "and trade names" Blemma-PE "," Blemma-PP "," Blemma-AP "manufactured by NOF Corporation.
−400 ”,“ Blemma-AE-350 ”,“ Blemma-PEP ”
And the like are typical examples.

Examples of the monomer (d) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth) acrylate. , T-butyl (meth) acrylate, isobutyl (meth) acrylate, cyclohexyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) ) Acrylate, α-chloroethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, ethoxypropyl (meth) acrylate, etc. Rate-based monomers; styrene and,
Styrene-based monomers such as methylstyrene, chlorostyrene, and methoxystyrene;

Monomers containing hydroxyl groups such as 2-hydroxyethyl (meth) acrylate, 2 (3) -hydroxypropyl (meth) acrylate, 4-hydroxybutyl acrylate and mono (meth) acrylate of allyl alcohol polyhydric alcohol Body; 2-aminoethyl (meth)
Acrylate, dimethylaminoethyl (meth) acrylate, 3-aminopropyl (meth) acrylate, 2
-Amino group-containing monomers such as butylaminoethyl (meth) acrylate and vinylpyridine; glycidyl (meth)
Acrylate or allyl glycidyl ether, an epoxy group-containing monomer or oligomer obtained by reacting an epoxy compound having two or more glycidyl groups with an ethylenically unsaturated monomer having an active hydrogen atom; acetoacetoxyethyl (meth) ) Carbonyl group-containing monomers such as acrylate and diacetone (meth) acrylamide;
Representative examples include N-methylolacrylamide having a -methylol group, vinyl acetate, vinyl chloride, and further, ethylene, butadiene, acrylonitrile, dialkyl fumarate, and the like.

Further, between the monomer (a) and the monomer (b),
Form an emulsion polymer having an internal crosslinked structure,
Divinylbenzene or ethylene glycol di (meth) acrylate which undergoes an internal crosslinking reaction to a part of the monomer (d),
Monomers having two or more polymerizable unsaturated double bonds in the molecule, such as trimethylolpropane tri (meth) acrylate and allyl (meth) acrylate; and functional groups that react with each other at the temperature during the emulsion polymerization reaction A monomer mixture containing a combination of monomers having, for example, an ethylenically unsaturated monomer having a functional group such as a combination of a carboxyl group and a glycidyl group or a combination of a hydroxyl group and an isocyanate group; An ethylenically unsaturated monomer having an alkoxysilyl group such as (meth) acryloxypropyltrimethoxysilane, (meth) acryloxypropyltriethoxysilane, (meth) acryloxypropylmethyldimethoxysilane, etc. It is also possible.

In the emulsion polymerization method, the above-mentioned ethylenically unsaturated monomer is subjected to one step or two steps in water according to a conventional method.
An emulsion resin particle (A) in which the emulsion polymer has one phase or two or more phases, that is, an outermost phase and one or more internal phases, is formed by a multi-stage emulsion polymerization method which is repeated at least steps. Is the way. Typical examples of the single-stage and multi-stage emulsion polymerization methods include the above-mentioned monomers in water in the presence of an emulsifier and a polymerization initiator, and further, if necessary, a chain transfer agent and an emulsion stabilizer. A method in which emulsion polymerization is carried out under heating at a temperature of up to 90 ° C., or the method is repeated a plurality of times.

In the emulsion polymerization, a monomer batch charging method in which monomers are charged all at once, a monomer dropping method in which monomers are continuously dropped, and a method in which a monomer, water and an emulsifier are used. A pre-emulsion method in which the mixture is emulsified in advance and the resulting mixture is dropped, or a method in which these are combined, and the like, may be used. Examples of the emulsifier include fatty acid salts such as sodium lauryl sulfate, higher alcohol sulfates, alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, polyoxyethylene alkyl ether sulfate, and polyoxyethylene nonylphenyl ether sulfonic acid. Salts, polyoxyethylene-polyoxypropylene glycol ether sulfates, anionic surfactants such as so-called reactive emulsifiers having a polymerizable carbon-carbon unsaturated double bond and a polymerizable carbon-carbon unsaturated double bond in the molecule A polyoxyethylene alkyl ether, a polyoxyethylene nonylphenyl ether, a sorbitan fatty acid ester, a polyoxyethylene fatty acid ester, a polyoxyethylene-polyoxypropylene block copolymer, or the aforementioned Nonionic surfactants such as reactive emulsifiers having a skeleton and a polymerizable carbon-carbon unsaturated double bond in the molecule; cationic surfactants such as alkylamine salts and quaternary ammonium salts; (modified) Polyvinyl alcohol and the like.

As the polymerization initiator, those generally used for radical polymerization can be used, and among them, water-soluble ones are preferable. For example, potassium persulfate, ammonium persulfate, etc. Persulfate; 2,
Azo such as 2′-azobis (2-aminodipropane) hydrochloride, 4,4′-azobis-cyanovaleric acid, and 2,2′-azobis (2-methylbutanamidooxime) dihydrochloride tetrahydrate System compounds: peroxides such as hydrogen peroxide and t-butyl hydroperoxide. Furthermore, L
-A redox system in which a reducing agent such as ascorbic acid or sodium thiosulfate is combined with ferrous sulfate or the like can also be used.

Examples of the chain transfer agent include long-chain alkyl mercaptans such as n-dodecyl mercaptan, aromatic mercaptans, and halogenated hydrocarbons. As the emulsion stabilizer, polyvinyl alcohol, hydroxyethyl cellulose,
Polyvinyl pyrrolidone and the like can be mentioned. In the present invention, in producing the emulsion resin particles (A) serving as a binder by the method described above, the ratio of each monomer is as follows. The molar ratio [(a) / (b)] of the monomer (a) and the monomer (b) is 0.1 to 10, preferably 0.2 to 3, and In the above, the total amount of the monomer (a) and the monomer (b) is 0.5 to 60% by mass, preferably 1 to 10% by mass, and the amount of the monomer (c) is Is 1 to 20% by mass, preferably 3 to 15% by mass.
% By mass, with the balance being monomer (d).

In the range of the molar ratio of the monomers (a) and (b), a cured coating film having a three-dimensionally crosslinked structure is formed by self-crosslinking, and the blocking resistance and the effect of preventing contaminants from seeping out. Excellent coating film is obtained. When the total amount of the monomer (a) and the monomer (b) is less than 0.5% by mass, the effect of preventing contaminants from seeping out is deteriorated. And the workability of coating and the like deteriorate. When the amount of the monomer (c) is less than 1% by mass, the freeze-thaw stability of the coating material is deteriorated.
Exceeding this is not preferred because the water resistance of the resulting coating film deteriorates.

The emulsion resin particles (A) obtained under such conditions can take any form of uniform structure (single phase) particles or heterophase structure (usually two to five phase) particles. However, from the viewpoint of higher blocking resistance, stain resistance, and low tackiness, the glass transition temperature (hereinafter, referred to as Tg) of the emulsion polymer forming the outermost phase is -50 to
10 ° C., preferably −30 ° C. to 0 ° C., and the Tg of at least one emulsion polymer inside the outermost phase of the particles is:
For example, it is most preferable to use the hetero-phase structure emulsion resin particles formed by combining the monomers (a) to (d) having a temperature of 30 to 110 ° C, preferably 40 to 90 ° C. In the present invention, the Tg of the emulsion polymer is calculated using the following FOX formula.

1 / Tg = W ₁ / Tg ₁ + W ₂ / Tg ₂ +...
+ W _i / Tg _i +... + W _n / Tg _n [The FOX formula indicates that the glass transition temperature of the homopolymer of each monomer constituting the polymer composed of n kinds of monomers is Tg _i (K ), and has a weight fraction of each monomer in the _{W i, (W 1 + W} 2 + ··
+ W _i +... + W _n = 1). In addition, since low-temperature film-forming properties are required, monomers (a) to
By appropriately combining (d), the MFT of the emulsion polymer is 10 ° C.
In the following, it is necessary to use a material having a temperature of preferably 0 ° C. or less.

By satisfying such conditions, it is possible to use a VOC such as a film-forming aid or an antifreezing agent,
Even when used, low-temperature film formation,
It has excellent freeze-thaw stability, blocking resistance, water resistance, etc., and also has excellent storage stability even when it contains a pigment that has adsorptivity to harmful substances such as formalin and toluene, and pollutants. Emulsion resin particles (A) that can form a coating film without bleeding. Further, the emulsion polymer forming one phase of the outermost phase and its inner phase may be a combination of monomers satisfying the above-mentioned Tg and MFT.
Above, and a monomer such that the MFT of the binder comprising the hetero-phase structure emulsion particles is lower than the MFT of the polymer obtained by uniformly and uniformly emulsion-polymerizing all the monomers forming the particles in one step. It is appropriate to select and use.

Since the emulsion resin particles use a carboxyl group-containing monomer, it can be neutralized with a neutralizing agent such as ammonia, dimethylethanolamine or triethanolamine. Storage stability can be greatly improved. Furthermore, compounds containing two or more, preferably two to three hydrazide groups in the molecule, such as carbohydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, and sebacic acid dihydrazide. , Dodecane diacid dihydrazide, isophthalic acid dihydrazide, citric acid trihydrazide, 1,
For example, 2,4-benzenetrihydrazide, thiocarbodihydrazide, or the like is firmly compounded by adding an amount of 0.1 to 2.0 equivalents of hydrazide group to 1 equivalent of carbonyl group of the monomer. A crosslinked coating film is obtained, and higher blocking resistance and coating film strength can be obtained.

The pigment (B) used in the present invention includes titanium oxide, red iron oxide, carbon black, calcium carbonate, barium carbonate, talc, clay, mica, alumina, alum, terra alba, magnesium hydroxide, magnesium oxide, diatomaceous earth. Color pigments for paints and extenders can be used without particular limitation. The room temperature-curable aqueous emulsion paint of the present invention has an absorption and deodorization property against harmful substances such as formalin and toluene in the air, and pollutants such as cigarette tar, soot, scale, oily smoke and rain leak stains. Even if the pigment is contained, the storage stability is excellent, and as such an adsorbent pigment, from the viewpoint of the adsorption capacity and the storage stability of the paint, frypontite, activated zinc white and magnesium silicate are particularly preferable. Suitable. These pigments
It is preferable to mix in such an amount that the volume concentration (PVC) relative to the solid content of the coating material is 70% or less, preferably 10 to 60%.

Frypontite typically has the basic chemical structural formula: (Zn _3-X Al _X ) (Si _{2 -X} Al _X ) O ₅ (OH) ₄ , wherein x is 0 To 1.75, preferably 0.3 to 1.75.
0. ), And the composition expressed as an oxide is Si
O ₂ 5 to 45 mol%, ZnO 35 to 65 mole% and,
Al ₂ O ₃ having a fine laminated plate crystal of 0 to 60 mol%,
Fine particles having an average particle size of about 0.5 to 20 μm and a specific surface area of about 20 to 300 m ² / g. Such frypontite is described in Japanese Patent Publication No. 4-51485, Japanese Patent Publication No. 5-44405, and the like.
Examples of commercially available products include “Mizukanite AP” and “Mizukanite HP” manufactured by Mizusawa Chemical Industry Co., Ltd.

Active zinc white is a fine particle having a particle diameter of 0.2 μm or less, a particle diameter smaller than that of ordinary zinc white, and a specific surface area of about 50 to 150 m ² / g. Examples of commercially available products include “Active Zinc White Azo” (trade name, manufactured by Shodo Chemical Co., Ltd.). The magnesium silicate is typically a hydrous magnesium silicate represented by the chemical structural formula: 2MgO.6SiO ₂ .XH ₂ O, and has an average particle size of about 1 to about 1.
20 μm fine particles. Examples of commercially available products include “Kyoword 600” (trade name) manufactured by Kyowa Chemical Industry Co., Ltd. and “Aid Plus” (trade name) manufactured by Mizusawa Chemical Industry Co., Ltd.

The cold-setting aqueous emulsion paint of the present invention contains the above-mentioned emulsion resin particles, pigment and water, and further comprises a thickener, a defoamer, a preservative, a fungicide, if necessary. It is a paint containing various additives such as an antibacterial agent, an ultraviolet absorber and a light stabilizer. The cold-curable aqueous emulsion paint of the present invention has a solid content of 30 to 8 for example.
It is preferable that the composition be 0 mass%, preferably 50 to 75 mass%. The coating material of the present invention can be applied to various coating materials such as an inorganic material, a metal material, a wood material, and a plastic material.
Alternatively, an excellent coating film can be formed by applying a coating means such as a brush, a spray, a roller, or the like, and then drying naturally or forcibly drying at a temperature of 100 ° C. or less.

[0028]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “parts” and “%” are shown on a mass basis unless otherwise specified. <Synthesis of Aqueous Emulsion Resin Liquids (1), (2), (7) and (8)> Ion-exchanged water 190 was placed in a four-neck separable flask equipped with a stirrer, thermometer, cooling pipe and dropping device. Parts and sodium hydrogen carbonate (pH adjuster) 1
, 3 parts of sodium polyoxyethylene alkyl ether sulfonate (surfactant), the temperature inside the flask was raised to 80 ° C. while replacing the inside of the flask with nitrogen, and 1 part of potassium persulfate (polymerization initiator) was added. A solution in which 0.5 part of ammonium persulfate (polymerization initiator) was continuously dissolved in 10 parts of ion-exchanged water was continuously added dropwise over 4 hours to the emulsion A shown in Table 1 which had been stirred and emulsified in a separate container. Was added dropwise in 0.5 hours. Thereafter, the mixture was aged while continuing stirring at 80 ° C. for 2 hours, cooled to 25 ° C., and adjusted to pH 9.0 with 28% aqueous ammonia to obtain an aqueous emulsion resin liquid in which emulsion resin particles were dispersed.

<Aqueous emulsion resin liquid (3),
(4), synthesis of (9) to (11)> stirrer, thermometer,
190 parts of ion-exchanged water, 1 part of sodium hydrogen carbonate, and 3 parts of sodium polyoxyethylene alkyl ether sulfonate were charged into a four-neck separable flask equipped with a cooling pipe and a dropping device, and the inside of the flask was replaced with nitrogen. After the temperature was raised to 80 ° C., 1 part of potassium persulfate was added, and subsequently, the emulsion A shown in Table 1 which had been stirred and emulsified in another container was continuously dropped over 3 hours. After the completion of the first dropping, the temperature was lowered to 70 ° C. in one hour. Subsequently, the emulsion B shown in Table 1 which had been stirred and mixed in the same manner as in the first stage was continuously added dropwise over 3 hours. Subsequently, a solution prepared by dissolving 0.5 part of ammonium persulfate in 10 parts of ion-exchanged water was added dropwise over 30 minutes, aged at 70 ° C. for 2 hours while stirring, cooled to 25 ° C., and then cooled to 28% aqueous ammonia. By adjusting the pH to 9.0, an aqueous emulsion resin liquid in which the emulsion resin particles were dispersed was obtained.

<Synthesis of Aqueous Emulsion Resin Liquids (5) and (6)> In a four-neck separable flask equipped with a stirrer, a thermometer, a cooling tube, and a dropping device, 190 parts of ion-exchanged water and hydrogen carbonate were added. After charging 1 part of sodium and 3 parts of sodium polyoxyethylene alkyl ether sulfonate, the temperature inside the flask was raised to 80 ° C. while replacing the inside of the flask with nitrogen, 1 part of potassium persulfate was added, followed by stirring and emulsification in another container. The emulsion A shown in Table 1 was dropped continuously over 2 hours, and the emulsion B was dropped over 2 hours. After dropping the emulsions A and B in two stages, the temperature was lowered to 70 ° C. in one hour. Subsequently, the emulsified product C shown in Table 1, which had been stirred and mixed in a separate container as in the first and second stages, was continuously dropped over 3 hours. Subsequently, a solution prepared by dissolving 0.5 part of ammonium persulfate in 10 parts of ion-exchanged water was added to 3 parts.
The mixture was dropped over 0 minutes, aged at 70 ° C. for 2 hours while stirring, cooled to 25 ° C., and added with 28% aqueous ammonia.
By adjusting to H9.0, an aqueous emulsion resin liquid in which the emulsion resin particles were dispersed was obtained.

The abbreviations of the raw materials shown in Table 1 have the following meanings. The value in parentheses of the raw material indicates the Tg of the homopolymer of each monomer used for calculating the glass transition temperature. MMA: methyl methacrylate (105 ° C) BA: butyl acrylate (-54 ° C) ST: styrene (100 ° C) GMA: glycidyl methacrylate (41 ° C) MAA: methacrylic acid (185 ° C) PEG (1): polyethylene glycol chain Containing monomer (−50 ° C.) H ₂ C ＣC (CH ₃ ) —C (＝ O) —O (CH ₂ CH ₂ O)
₈ H PEG (2): polyethylene glycol chain-containing monomer (−50 ° C.) H ₂ C ＣCH—CH ₂ —O— (CH ₂ CH ₂ O) ₆ H PPG: polypropylene glycol chain-containing monomer (−
50 ° C.) H ₂ C ＝ C (CH ₃ ) —C (＝ O) —O (CH ₂ CH ₂ (C
_{H 3) O) 6 H ATFA1} : caprolactone-modified acetoacetoxy acrylate (PLACCEL ATFA1; manufactured by Daicel Chemical Industries: -30
° C) ATFM2: Caprolactone-modified acetoacetoxymethacrylate (Placcel ATFM2; manufactured by Daicel Chemical Industries: -30)
° C) In the Tg shown in Table 1, [Total (° C)]
Refers to the T of the polymer obtained when a mixture of the emulsion A and the emulsion B (and the emulsifier C) is emulsion-polymerized in one step.
g ".

[0032]

[Table 1] Note: * indicates a reference example.

<Preparation of Pigment Paste> The following components were placed in a stainless steel container and stirred with a stirrer for 30 minutes to produce a pigment paste. Tap water 168 parts Titanium white 260 parts Calcium carbonate 150 parts Dispersant 6 parts Defoamer 4 parts Thickener 2 parts

<Examples 1 to 8> and <Comparative Examples 1 to 5> The components shown in Table 2 were stirred with a stirrer for 30 minutes to prepare an aqueous emulsion paint. In addition, "Mizukanite" (trade name, manufactured by Mizusawa Chemical Industry Co., Ltd.) was used as the frying ponite shown in Table 2, and "Activated Zinc Flower Azo" was used as the activated zinc flower.
"Kyoward 600" (trade name, manufactured by Kyowa Chemical Industry Co., Ltd.) was used as magnesium silicate. In addition, the film forming aid is 2,2,4-trimethyl-
1,3-pentanediol monoisobutyrate.

[0035]

[Table 2]

The coatings obtained in Examples 1 to 8 and Comparative Examples 1 to 5 were tested by the following methods to evaluate the performance.
The results are shown in the lower part of Table 2. <Low-temperature film-forming property> Each paint was applied to a glass plate using a 6-mil applicator in a low-temperature constant-temperature room at 5 ° C, and left for one day. The appearance of the obtained coating film was visually determined. In addition, in Comparative Examples 1 and 5, a test was performed before adding the film forming aid. Evaluation Criteria : Mud cracks, micro cracks, etc. were not observed at all, and the film was completely formed. Δ: Most of the film was formed, but cracks were locally observed. C: Cracks and peeling were observed over the entire surface, and no film was formed.

<Freeze-Thaw Stability> Each paint was almost completely filled in a 1-liter inner coat can, then sealed, stored in a freezer at -20 ° C. for 24 hours, and frozen. Next, after taking out from the freezer and leaving at 20 ° C. for 24 hours, the mixture is stirred and visually checked for the state of the paint, and the change in viscosity before freezing and the appearance of the paint film when coated on a glass plate with a 6 mil applicator are visually determined. did. Evaluation criteria ：: No solidification occurred, no change in viscosity, and good appearance of coating film. Δ: There was a change in viscosity, but no coagulation occurred, and the appearance of the coating film was good. ×: Generation of coagulated material or aggregation / gelation is observed.

<Storage Stability> In the same manner as described above, a 1-liter inner can was almost completely filled and hermetically sealed, and then allowed to stand in a constant temperature room at 20 ° C. for 30 days to determine the state of the paint. Evaluation criteria ：: There is almost no change in viscosity, and no generation of coagulated material / gel is recognized. Δ: Fluctuation in viscosity was observed to some extent. X: Fluctuation in viscosity is remarkable, or aggregation / gelation is observed.

<Water resistance> Each paint was applied on the surface of a glass plate with a 6 mil applicator, and dried at room temperature for 7 days. It was determined visually. However, for paints that do not form a film at room temperature (Comparative Examples 1 and 5), a film forming aid is formed at room temperature.
Added until FT was reached. Evaluation criteria ○: No abnormality △: Swelling (swelling) is locally observed. ×: Swelling is observed over the entire surface, or elution of the coating film is confirmed.

<Adhesiveness (Accelerated Stain)> Each paint is applied on a glass plate surface with a 6 mil applicator, and dried at room temperature for 7 days. Thus, a carbon paper is placed, and a weight is placed thereon. The weight is adjusted to have a load equivalent to 0.01 kg / cm ² . After applying a load for 24 hours, the carbon paper is slowly peeled off, and the appearance of the coating film is checked. For coating materials that do not form a film at room temperature (Comparative Examples 1 and 5), a film forming aid is added in the same manner as described above. Evaluation criteria A : No carbon is attached at all. ：: Carbon is attached to less than 30% of the area under load. Δ: Carbon is attached to 30% or more and less than 70% of the area under load. ×: Carbon is attached to 70% or more of the area where the load was applied.

<Blocking resistance> After a coating film was formed on a glass plate in the same manner as described above, gauze was placed on the coating film, and a load of 0.01 kg / cm ² was applied with a weight as described above. I do. Next, the test plate on which the weight is placed is placed in a thermostat set at 50 ° C. and heated for 1 hour. After being taken out of the thermostat, it is allowed to cool to 20 ° C., and the gauze is slowly peeled off except for the weight. At that time, the peeling resistance and traces of gauze were visually determined. Evaluation criteria A : Gauze dropped naturally, and traces of gauze hardly remained on the coating film. 〇: The gauze does not fall spontaneously, but almost no trace of the gauze remains on the coating film. Δ: The gauze can be peeled off with a very small amount of force, and traces of the gauze are slightly observed. X: Part of the coating film was peeled off when the gauze was peeled off, and traces of the gauze remained clearly.

<Stain resistance> 500 ml of ion-exchanged water was added to 50 g of tobacco leaves, and the mixture was allowed to stand at room temperature for 24 hours to obtain a tobacco leaf extract. 80 ° C under reduced pressure
Then, the extract was concentrated until the extract became 200 ml or less, and ion-exchanged water was added to 200 ml to obtain a tobacco leaf extract for exudation test. The extract was applied to a gypsum board coated with a commercially available white emulsion paint using a 6-mil applicator and allowed to stand at room temperature for 7 days. Each paint was applied twice on the contaminated test plate thus obtained with a 6 mil applicator, dried at room temperature for 2 days, and the surface of each paint film was visually evaluated.

Evaluation Criteria : No exudation of contaminants at all or slight exudation is observed, but there is no practical effect. Δ: Seepage of contaminants is locally observed. ×: Seepage of contaminants was confirmed on the entire surface, and discoloration was remarkable.

<VOC Analysis> Each paint sample was subjected to 70 ×
A 150 mm glass plate is coated with a brush so as to have a coating mass of 1 g, and dried at room temperature for one day. After drying, the mixture is placed in a 1 L separable flask, and a closed circulation pump and a closed circulation device equipped with an activated carbon tube and a silica gel adsorption tube are installed (mini-chamber method specified by Nippon Paint Industry).
Thereafter, the pump was operated at a flow rate of 150 ml / min to circulate the atmosphere in the flask, and the VOC existing in the atmosphere was circulated.
Is adsorbed on activated carbon and silica gel. After circulating and adsorbing in the atmosphere for 2 days with a pump, the activated carbon and silica gel are washed and extracted with carbon disulfide and methanol,
The presence or absence of VOC released from the test plate coated with the carbon disulfide and methanol by GC-MS is confirmed.

Evaluation Criteria : VOC is not detected at all. X: VOC was detected. <Adsorption Test> Formaldehyde 0.1 mg was sealed in a 10 L desiccator, and after standing for 3 days, the concentration of formalin gas in the desiccator was measured using a gas detector tube, and it was 7 ppm.

Similarly, each paint sample is 70 × 150 m
m with a brush so as to have a coating mass of 1 g on a glass plate,
After drying at room temperature for 2 days, it is sealed together with 0.1 mg of formalin in a 10 L desiccator. Then, after leaving at room temperature for 3 days, the formalin concentration in the desiccator was measured using a gas detector tube, and the amount of formalin adsorbed on the painted test plate was confirmed. Evaluation criteria ：: Formalin detected was less than 1 ppm. Δ: 1 to 5 ppm of formalin was detected. X: 5 ppm or more of formalin was detected.

As apparent from Table 2 above, Examples 1 to 8
The emulsion paint of the present invention does not require any VOC such as a film-forming aid or an antifreezing agent,
Not only the melting stability was good, but also a contaminant did not exude from the surface to be coated, and a coating film capable of adsorbing harmful substances such as formalin could be formed. In particular, it can be seen that Examples 3 to 6 using emulsion particles having a different phase structure show outstanding blocking resistance and low tackiness.

On the other hand, when the MFT of the emulsion resin is 10 ° C.
In Comparative Example 1 (aqueous emulsion (7): MFT = 33 ° C.) and Comparative Example 5 (aqueous emulsion (11): MFT = 80 ° C.), a film could not be formed without a film forming aid, Further, since a large amount of a film forming aid is required, each property is significantly reduced by the film forming aid remaining in the film after film formation. Comparative Example 2 (aqueous emulsion (8): without ATFA1 and ATFM2) and Comparative Example 3 (aqueous emulsion (9) in which caprolactone-modified acetoacetoxy (meth) acrylate or a carboxyl group-containing ethylenically unsaturated monomer was not copolymerized. ): Without MAA) was inferior in the storage stability of the paint, and slightly inferior in the strength of the coating film and the power to adsorb contaminants. Comparative Example 4 not containing an ethylenically unsaturated monomer having at least one of a polyethylene glycol chain and a polypropylene glycol chain (aqueous emulsion (10))
Resulted in poor freeze-thaw stability and resulted in complete aggregation after the test.

[0049]

The cold-curing aqueous emulsion paint of the present invention has a low VOC and excellent freeze-thaw stability, and the resulting coating film has excellent low-temperature film formability, water resistance, blocking resistance, etc. In addition, it has excellent storage stability even if it contains pigments that are adsorbable to pollutants such as harmful substances such as VOC and formalin in the atmosphere and tobacco tar, soot, oil smoke, and stains from rain leak. In addition, it is possible to form a coating film without exudation of contaminants, and therefore, it can be suitably used as a repainting paint for a room contaminated with these contaminants.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuyoshi Tsuneda 1-981 Shimonaga, Nishinasuno-machi, Nasu-gun, Tochigi F-term (reference) 4J038 CG031 CG141 CH141 CH161 CJ131 GA02 GA06 KA08 KA09 MA08 MA10 NA01 NA26 NA27

Claims (7)

[Claims] 1. (A) (a) a lactone-modified acetoacetoxy (meth) acrylate monomer, (b) an ethylenically unsaturated monomer having a carboxyl group, and (c) at least a polyethylene glycol chain and a polypropylene glycol chain. A room-temperature-curable emulsion paint containing an emulsion resin particle comprising a copolymer containing an ethylenically unsaturated monomer having one of the above as a component, and (B) a pigment, wherein (1) the copolymer In the union, the molar ratio of the monomer (a) to the monomer (b) [(a) / (b)] is
0.1 to 10, and among all monomers, monomer (a)
And the total amount of the monomer (b) is 0.5 to 60% by mass, the amount of the monomer (c) is 1 to 20% by mass, and Saturated monomer (d)
(2) a minimum film-forming temperature of the emulsion resin particles is 10 ° C. or lower. 2. The emulsion resin particles are hetero-phase structure emulsion resin particles obtained by a multi-stage emulsion polymerization method, wherein the emulsion polymer forming the outermost phase of the particles has a glass transition temperature of −50 ° C. to 10 ° C. The room-temperature curing according to claim 1, wherein the emulsion polymer, which is an emulsion polymer and forms at least one phase inside the outermost phase of the particles, is an emulsion polymer having a glass transition temperature of 30C to 110C. Water-based emulsion paint. 3. The monomer (a) is represented by the following formula (I): CH ₂ ＣC (R) —C (＝ O) O—CH ₂ CH ₂ —O—
[C (= O) - ( CH 2) 5 O-] n -C (= O) CH 2 C
(= O) CH ₃ wherein R is a hydrogen atom or a methyl group, and n is 1
Or 2. The cold-setting aqueous emulsion paint according to claim 1, which is a monomer represented by the formula: 4. The monomer (c) is represented by the following formula (II): CH ₂ ＣC (R ¹ ) —C (＝ O) —O— [X—O] _n —R ² (wherein R ¹ is a hydrogen atom or a methyl group, and R ² is
X is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms;
— (CH ₂ ) ₂ — or —CH ₂ CH (CH ₃ ) —, and n
Is an integer of 1 to 30. The cold-setting aqueous emulsion paint according to claim 1, which is a monomer represented by the formula: 5. The monomer (c) is represented by the following formula (III): CH ₂ ＣC (R ¹ ) — (CH ₂ ) _m —O— [X—O] _n —R ² (wherein: R ¹ , R ² , X and n have the same meanings as in formula (II), and m is an integer of 1 to 30). Curable aqueous emulsion paint. 6. The monomer (c) has the following formula (IV): CH ₂ CR ¹ -C (＝ O) —O— (CH ₂ CH ₂ O) _m —
[CH ₂ —CH (CH ₃ ) —O] _n —R ² (wherein R ¹ and R ² have the same meanings as in formula (II), and m
And n are integers of 1 to 30. 2. The cold-setting aqueous emulsion paint according to claim 1, which is a monomer represented by the formula: 7. The pigment (B) is frypontite,
The cold-curable aqueous emulsion paint according to claim 1, which is at least one selected from the group consisting of activated zinc white and magnesium silicate.