JP2002145969A - Aqueous resin dispersion and water-based coating composition for inorganic building material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-based coating for inorganic building materials capable of forming films having excellent freezing and thawing adhesion and resistances to weather, warm water whitening and hot water whitening. SOLUTION: This aqueous resin dispersion is obtained by carrying out emulsion copolymerization of 0.01-5 wt.% of an α,β-ethylenically unsaturated monomer a containing a polyethylene glycol-polypropylene glycol block copolymer represented by the following formula (wherein, R denotes hydrogen atom or methyl group; and m and n denote each an integer of 1-20), 85-99.94 wt.% of an α,β-ethylenically unsaturated monomer b and 0.05-10 wt.% of a hydrophilic α,β-ethylenically unsaturated monomer c other than the monomer a in the presence of a surfactant having a polymerizable functional group in an aqueous medium using a polymerization initiator. The glass transition point of the resin determined by calculation is 20-80 deg.C and the resin is dispersed into particles having 50-250 nm particle diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aqueous resin dispersion,
And an aqueous coating composition for inorganic building materials obtained by mixing the same with a pigment dispersion. Specifically, α, β-ethylenically unsaturated monomers (a) containing a polyethylene glycol-polypropylene glycol block copolymer, α, β
Dispersing the ethylenically unsaturated monomer (b) and the hydrophilic α, β-ethylenically unsaturated monomer (c) other than the monomer (a) at a specific composition ratio in the presence of a radically polymerizable surfactant. The present invention relates to an aqueous resin dispersion obtained by emulsion-copolymerization using a water-soluble radical polymerization initiator in an aqueous medium so that the particle diameter of the body falls within a specific range. The aqueous coating composition for inorganic building materials is excellent in freeze-thaw adhesion, weather resistance, hot water whitening resistance, and hot water whitening resistance, and is also applied to adhesives, paper processing agents, and the like.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for non-polluting paints and safety and health in terms of environmental protection and health and safety.
The use of water-based paints instead of solvent-based paints is expanding. However, the water-based paint is mainly composed of particles of a resin such as vinyl acetate, acrylic, and acrylstyrene dispersed in water using a surfactant and a dispersant, and a pigment, a pigment dispersant, Because it is a dispersion resin containing a defoaming agent, thickener, film-forming aid, preservative, etc., when compared with solvent-based paints, wetting to the substrate, poor adhesion due to poor permeability There were problems such as reduction and water resistance due to water-soluble components. In particular, in the aqueous coating material for inorganic building materials, since the inorganic base material is porous, the surface strength is small and it is easy to absorb moisture,
In the case of water absorption and moisture absorption, the adhesion (also referred to as freeze-thaw adhesion) of the coating film at the time of repeated freezing and thawing decreases, and the problem that the coating film peels easily occurs.

[0003] As a method for solving such a problem of the water-based paint for inorganic building materials, a soap-free emulsion polymerization method using no dispersant, an emulsion polymerization method using a reactive surfactant, water glass and colloidal silica are used. Various methods of using an inorganic polymer and an organic polymer in combination have been studied. In fact, in the case of a coating film obtained by using a blend of a colloidal silica and an emulsion of an organic polymer or a coating containing an emulsion as a main component using the colloidal silica during polymerization, the hardness is high, and the water resistance is also good. It is. However, the mutual connection between the inorganic polymer and the emulsion is weak, and as a result, the durability of the coating film, especially the freeze-thaw adhesion, is deteriorated in the long term. Therefore, in order to strengthen the connection between the emulsion of the inorganic polymer and the organic polymer, a method of adding an alkoxysilane to a blend of these two polymers and a method of using a polymerizable monomer having an alkoxysilane group are disclosed in Japanese Patent Application Laid-Open No. HEI 1-1990.
It has been developed as typified by Japanese Patent Publication No. 0-246990. However, such an aqueous coating composition has improved weather resistance, but is insufficient in stability of itself and freeze-thaw adhesion of a coating film.

[0004] In order to improve the freeze-thaw adhesion of the coating film, a method of applying a sealer on the coating film has also been proposed. Moisture-curable urethane resins and solvent-based resins are used as resins used for inorganic base sealers,
There are problems such as their toxicity, fire danger due to the use of organic solvents, and environmental pollution. For this reason, an aqueous sealer containing a water-soluble resin or a water-dispersible resin as a main component has been studied, but the water-soluble resin has poor water resistance, and the water-dispersible resin has poor wettability and poor permeability to the base material. , An aqueous two-pack epoxy resin is generally used. However, since the aqueous two-pack epoxy resin is a two-pack mixed type, there are problems in handling and toxicity. In order to solve the above problems, Japanese Patent Application Laid-Open No. Hei 8-157774 proposes a technique of blending polyvinyl alcohol with an aqueous resin dispersion, but without using a sealer, weather resistance, freeze-thaw adhesion. A water-based paint for inorganic building materials having a durability sufficient to satisfy both of them has not yet been obtained.

[0005]

SUMMARY OF THE INVENTION The present invention relates to an aqueous coating composition for an inorganic building material characterized by forming a coating film having excellent freeze-thaw adhesion, weather resistance, hot water whitening resistance and hot water whitening resistance. The purpose is to provide.

[0006]

The present inventors have conducted intensive studies to improve the freeze-thaw adhesion, weather resistance, hot water whitening resistance, and hot water whitening resistance. As a result, a polyethylene glycol-polypropylene glycol block copolymer was obtained. Containing α,
β-ethylenically unsaturated monomer (a), α, β-ethylenically unsaturated monomer (b), and hydrophilic α, β-ethylenically unsaturated monomer (c) other than monomer (a) at a specific ratio In the presence of a surfactant having a polymerizable functional group,
This problem is solved by using an aqueous resin dispersion obtained by emulsion copolymerization using a water-soluble radical polymerization initiator in an aqueous medium so that the particle size of the dispersion falls within a specific range. They have found what can be done and have completed the present invention.

That is, a first aspect of the present invention is that an α, β-ethylenically unsaturated monomer (a) containing a polyethylene glycol-polypropylene glycol block copolymer represented by the following formula (i): 0.01 to 5% by weight %, Α, β-
85 to 99.94% by weight of an ethylenically unsaturated monomer (b) and 0.05 to 10% by weight of a hydrophilic α, β-ethylenically unsaturated monomer (c) other than the monomer (a) (provided that:
The sum of (a) to (c) is 100% by weight. ) In the presence of a surfactant (e) having a polymerizable functional group capable of undergoing radical polymerization in an aqueous medium using a radical polymerization initiator to obtain an aqueous dispersion of a resin (p) obtained by emulsion copolymerization. The glass transition point Tg value of the resin (p ′) calculated from the FOX equation assuming that the monomer (a), (b) and (c) is composed of the monomers (a), (b) and (c) is 20 to 80 ° C. ) Is dispersed in a particle size of 50 to 250 nm.

Embedded image (Wherein, R is a hydrogen atom or a methyl group, and m and n are 1 to 20)
Represents an integer. A second aspect of the present invention relates to an aqueous coating composition for an inorganic building material, which is obtained by mixing the aqueous resin dispersion according to the first aspect of the present invention and a pigment dispersion. The third aspect of the present invention is that the performance of the coating film obtained from the aqueous coating composition for inorganic building materials is evaluated according to a predetermined test method. The gloss retention by accelerated weather resistance is 80% or more, and the freeze-thaw adhesion is 4 points. As described above, the present invention relates to the aqueous coating composition for an inorganic building material according to the second aspect of the present invention, wherein the hot water whitening resistance is 4 or more and the hot water whitening resistance is 4 or more.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The aqueous resin dispersion (l) of the present invention comprises an α, β-ethylenically unsaturated monomer (a) containing a polyethylene glycol-polypropylene glycol block copolymer represented by the above formula (i), α, β- The presence of a surfactant (e) having a polymerizable functional group at a specific ratio of the ethylenically unsaturated monomer (b) and the hydrophilic α, β-ethylenically unsaturated monomer (c) other than the monomer (a) The resin obtained by emulsion copolymerization below is dispersed in a dispersion medium containing water as a main component.

Α, β-ethylenically unsaturated monomer (a) represented by the formula (i): The monomer (a) is a (meth) polymer of a block copolymer of a polyethylene glycol chain and a polypropylene glycol chain.
An acrylic acid ester (acrylic acid and methacrylic acid are abbreviated as (meth) acrylic acid). For example, polyethylene glycol-polypropylene glycol monomethacrylate (Blenmer 70PEP-350B (manufactured by NOF CORPORATION)), polyethylene glycol-polypropylene glycol monoacrylate and the like can be mentioned. In the formula (i), m and n are independently 1 to 20, preferably 2 to 10, and particularly preferably the sum of m and n is 4 to 15.
Is an integer. These can be used alone or in combination of two or more. The amount of the monomer (a) used is 0.1% based on the total of the monomers (a) to (c).
The range is from 01 to 5% by weight, preferably from 0.05 to 3% by weight. If the amount of the monomer (a) is less than the above range, the freeze-thaw adhesion of the coating film as an aqueous paint tends to decrease. If the amount is more than the above range, the hydrophilicity increases, so that hot water bleaching resistance and hot water bleaching occur. Is reduced.

Α, β-ethylenically unsaturated monomer (b) Examples of the monomer (b) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic acid. Butyl acid, (meth)
Hexyl acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)
Lauryl acrylate, (meth) alkyl C ₁ -C ₂₄ (meth) acrylic acid such as acrylic acid stearyl or,
Cycloalkyl esters; C ₂ -C ₈ hydroxyalkyl esters of (meth) acrylic acid such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; styrene, vinyltoluene, α-methylstyrene, N-vinylpyrrolidone; Aromatic unsaturated monomers such as vinylpyridine; epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate; 1-methyl 2-pyrrolidone (meth) acrylate;
Pyrrole ring-containing C ₁ -C ₂₄ alkyl esters of (meth) acrylic acid such as 1-ethyl 2-pyrrolidone (meth) acrylate; 1-methyl 2-oxazolidone (meth) acrylate, (meth) acrylic acid 1 - ethyl 2-oxazolidone such as (meth) alkyl ester of C ₁ -C ₂₄ oxazole ring-containing acrylic acid. These can be used alone or in combination of two or more.
The amount of the monomer (b) used is from the monomers (a) to
It is in the range of 85 to 99.94% by weight, preferably 92 to 98.95% by weight, based on 100% by weight in total of (c). When the amount of the monomer (b) used is small, the hydrophilicity of the obtained dispersing resin is high, so that the hot water whitening resistance and the hot water whitening resistance are low. When the amount is large, the freeze-thaw adhesion of the coating film is low. There is a tendency.

(A) Hydrophilic α, β-ethylenically unsaturated monomer other than (a) (c) Examples of the monomer (c) include acrylic acid, methacrylic acid, maleic acid, crotonic acid, and a polyoxyethylene chain. (Meth) acrylate; acrylamide, N-methylolacrylamide, N-butoxymethylacrylamide and the like. These can be used alone or in combination of two or more. The amount of the monomer (c) used is in the range of 0.05 to 10% by weight, preferably 1 to 5% by weight, based on the total of the monomers (a) to (c). When the amount of the monomer (c) used is small, the film-forming property of a coating film as a water-based paint and the pigment dispersion stability during the preparation of the paint tend to decrease, and as a result, the durability tends to decrease. The hot water whitening resistance and the hot water whitening resistance are reduced due to the high water resistance.

The Tg value is measured by a differential scanning calorimeter (DS)
It can be measured using a thermal analyzer such as C). For example, as examples of the two components, the glass transition points Tg1 and Tg2 of the homopolymers of the monomers (1) and (2) are known. In this case, the glass transition point Tg of the copolymer composed of the two components of the monomers (1) and (2) can be obtained as a calculated value by the FOX formula (which is an example of the two components) shown in the following formula. it can. 1 / Tg = W1 / Tg1 + W2 / Tg2 (W1 +
W2 = 1) W1: weight fraction of monomer (1) W2: weight fraction of monomer (2) Tg1: Tg value of homopolymer of monomer (1) (unit: K) Tg2: homopolymer of monomer (2) Tg value (unit: K) The Tg values of the polymers in the examples and comparative examples in the present invention are calculated by generalizing the above equation to a multi-component system.

The glass transition point Tg of the resin (p ') calculated from the FOX formula when the monomer (a), (b) and (c) is composed of the monomers (a), (b) and (c) is from 20 ° C. to 80 ° C., preferably from 30 ° C. The range of -60 ° C is good. Tg of resin for dispersion
If the value is lower than 20 ° C., the water resistance of the coating film as a water-based paint,
Warm water resistance tends to decrease, and when the Tg value is higher than 80 ° C., the freeze-thaw adhesion of a coating film as an aqueous paint decreases.

Aqueous resin dispersion (l) The above monomers (a), (b) and (c) are mixed with a radical polymerization initiator in an aqueous medium in the presence of a surfactant (e) having a polymerizable functional group. Emulsion polymerization is used to polymerize and obtain a dispersion of resin (p). The emulsion polymerization method is not particularly limited, and a monomer dropping method in which a mixture of radically polymerizable monomers (a), (b), and (c) is dropped in the presence of water, an emulsifier, and an initiator; A pre-emulsion method in which a mixture of (b) and (c) is emulsified in the presence of water and an emulsifier, and polymerization is performed while dropping the mixture; water, an emulsifier, an initiator, a monomer (a),
A one-bath polymerization method in which radical polymerization is performed in the presence of all of the mixture of (b) and (c) is included. For the monomer dropping method and the pre-emulsion method, the dropping amount is 1 to 50.
% By weight, preferably 1 to 30% by weight, can also be added before the start of the polymerization. From the viewpoint of safety, the monomer dropping method and the pre-emulsion method are preferable, and among them, the pre-emulsion method is preferable.

Surfactant having a polymerizable functional group capable of radical polymerization (e) Examples of the surfactant (e) include anionic and nonionic surfactants. As the anionic surfactant, a surfactant in which a radically polymerizable unsaturated double bond is introduced into the molecule of the sulfate salt of polyoxyethylene alkylphenyl ether, specifically, Aqualon HS-10 (No. Adecaria Soap SE-10N (manufactured by Asahi Denka Kogyo Co., Ltd.); a surfactant having a radically polymerizable unsaturated double bond introduced into the molecule of an alkyl sulfosuccinate salt, specifically In general,
Eleminor JS2, Eleminor RN-30 (manufactured by Sanyo Chemical Industries, Ltd.), Latemul S-180, Latemul S
-180A (manufactured by Kao Corporation). Examples of the nonionic surfactant include surfactants in which a radically polymerizable unsaturated double bond is introduced into the molecule of polyoxyethylene alkyl phenyl ether, Aqualon RN-20, RN-50 (above, first) Industrial Pharmaceutical Co., Ltd.), Adecaria Soap NE-20, NE-40 (all manufactured by Asahi Denka Kogyo Co., Ltd.) and the like. These can be used alone or in combination of two or more.

Radical Polymerization Initiator The radical polymerization initiator in the present invention, which is capable of undergoing radical decomposition by heat or a reducing substance to cause addition polymerization to a monomer, is a water-soluble or oil-soluble persulfate, Peroxides, azo compounds and the like can be used. Preferred are water-soluble radical polymerization initiators. For example, persulfates such as hydrogen peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate; benzoyl peroxide, lauroyl peroxide, peracetic acid, persuccinic acid, di-t-butyl peroxide, t-butyl hydroperoxide Organic peroxides such as oxide, cumene hydroperoxide, t-butylperoxybenzoate, 2,2-azobisisobutyronitrile, 2,2-azobis (2-diaminopropane) hydrochloride, 4,4-azobis Examples include azo compounds such as-(4-cyanovaleric acid) and 2,2-azobis- (4-methoxy-2,4-dimethylvaleronitrile), but are not particularly limited. These polymerization initiators may be used alone, and
Two or more types may be used in combination. Monomers (a) to (c)
The amount of the polymerization initiator to be used is not particularly limited. In addition, when it is desired to accelerate the polymerization rate and polymerize at a low temperature, it is necessary to reduce sodium hyposulfite, ferrous chloride, ascorbate, Rongalit, sodium hypophosphite monohydrate and other hypophosphites. The agent can be used in combination with a polymerization initiator. In order to control the molecular weight, a chain transfer agent such as octyl mercaptan, dodecyl mercaptan, and 2-ethylhexyl thioglycolate can be added.

The particle size of the resin (p) dispersed in the aqueous resin dispersion (l) is 50 to 250 nm, preferably 80 to 250 nm.
A range of 150 nm is good. If the particle diameter is smaller than 50 nm, the stability of the obtained dispersion resin will be poor. On the other hand, when the particle diameter is larger than 250 nm, the wet-penetrability to the base material is reduced, so that the freeze-thaw adhesion of a coating film as an aqueous coating material tends to be reduced. Further, the aqueous resin dispersion (l) includes:
Ingredients added to the water-based paint and the like, for example, a surfactant,
Thickeners, defoamers, dyes, preservatives and the like may be added.

Pigment Dispersion (k) The pigment dispersion (k) according to the present invention is obtained by dispersing the pigment (g) in, for example, water, preferably deionized water. At this time, an antifoaming agent, aqueous ammonia, silica powder, or the like can be added as necessary. Pigment (g) As the pigment (g), for the inorganic type, mica, talc, kaolin, calcium carbonate, anhydrous silicic acid, aluminum oxide,
Extenders such as barium sulfate; coloring pigments such as red iron oxide, black iron oxide, black iron oxide, chromium oxide, ultramarine, navy blue and carbon black; white pigments such as titanium dioxide and zinc oxide; titanium mica, fish phosphor foil, and oxychloride Pearl pigments such as bismuth; special functional pigments such as boron nitride, photochromic pigments, synthetic fluorophlogopite, fine-grained composite powder, etc. Dyes, lakes, organic pigments, etc. as organic synthetic pigments in organic systems is there. These can be used alone or in combination of two or more. The pigment (g) can be dispersed by a known slurrying method. As the dispersing device, a homomixer, a disper, a sand mill, a ball mill, a roll mill, a kneader and the like can be used. If necessary, known dispersing agents (surfactants, thickeners, etc.), antifreezing agents, preservatives, antifungal agents and the like may be added.

Aqueous coating composition for inorganic building materials (m) The aqueous coating composition for inorganic building materials (m) is obtained by mixing the aqueous resin dispersion (l) and the pigment dispersion (k). The performance of the coating film obtained from the aqueous coating composition (m) for inorganic building materials was evaluated according to the test method described later, and the gloss retention by accelerated weather resistance was 80% or more, the freeze-thaw adhesion was 4 points or more, and hot water resistance. Whitening property is 4 points or more, and hot water whitening property is 4 points or more.

[0020]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. In the Examples and Comparative Examples, parts and% are by weight.
The Tg value is a value obtained by calculating the FOX formula for the resin (p ′). The particle diameter is a volume average particle diameter determined by light scattering.

[Synthesis of Aqueous Resin Dispersion] (Example A-1) As a first step, 15.2 deionized water was used.
Parts, surfactant (Eleminol JS-2: manufactured by Sanyo Chemical Co., Ltd.) 1.8 parts, methyl methacrylate 24.5 parts, cyclohexyl methacrylate 15.0 parts, butyl acrylate 9.3 parts, acrylic acid 0.7 Part, ethylene glycol-
Α, containing a propylene glycol block copolymer
0.5 part of Blenmer 70PEP-350B was mixed as the β-ethylenically unsaturated monomer (a) to obtain a uniform monomer emulsion. Next, as a second step, 32.1 parts of deionized water and 0.2 parts of Eleminor JS-2 were placed in a 2-liter four-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer. A part of the monomer mixed solution obtained in the first step was charged and heated to 80 ° C. under a nitrogen gas stream, a polymerization initiator was added thereto, and the remaining monomer mixed solution was added dropwise over 2 hours. The polymerization temperature at this time is 79
~ 81 ° C, and maintained at the same temperature after dropping.
After maintaining for a period of time, the mixture was cooled to room temperature, neutralized with 0.4 part of 25% aqueous ammonia, and filtered with a 200-mesh filter cloth. The dry weight of the filtered agglomerate was very low, 0.002% of the total monomer. The obtained aqueous emulsion has a nonvolatile content of 50% and an average particle size of 120 n.
The m and Tg values were 49 ° C.

(Example A-2) Blemmer 70 PEP-
The same operation as in Example A-1 was performed except that 350B was changed to Blemmer AEP. The dry weight of the filtered agglomerates was very low, 0.001% of the total monomer. The nonvolatile content of the obtained aqueous emulsion is 50%,
The average particle size was 125 nm, and the Tg value was 46 ° C.

Example A-3 Methyl methacrylate was converted to 2
Except that 9.5 parts and 4.3 parts of butyl acrylate were used,
It carried out by the same operation as Example A-1. The dry weight of the filtered agglomerate was very low, 0.002% of the total monomer. The resulting aqueous emulsion had a nonvolatile content of 5
0%, the average particle diameter was 110 nm, and the Tg value was 68 ° C.

Example A-4 Example A-1 except that butyl acrylate was changed to 2-ethylhexyl acrylate.
The same operation was performed. The dry weight of the filtered agglomerate was very low, 0.002% of the total monomer.
The obtained aqueous emulsion had a nonvolatile content of 50%, an average particle diameter of 100 nm, and a Tg value of 41 ° C.

(Example A-5) The same operation as in Example A-1 was carried out except that in the second stage, 0.4 part of Eleminor JS-2 charged in the four-necked flask was used. The dry weight of the filtered agglomerate was as low as 0.008% based on all monomers. The non-volatile content of the obtained aqueous emulsion is 50
%, The average particle diameter was 80 nm, and the Tg value was 41 ° C.

(Comparative Example A-1) The same operation as in Example A-1 was carried out except that Blemmer 70 PEP-350B used in Example A-1 was not used. The dry weight of the filtered agglomerate was very low, 0.002% of the total monomer. The obtained aqueous emulsion had a nonvolatile content of 50%, an average particle size of 120 nm, and a Tg value of 49 ° C.

(Comparative Example A-2) Methyl methacrylate was replaced with 1
The same operation as in Example A-1 was carried out except that 2.0 parts and butyl acrylate were changed to 21.8 parts. The dry weight of the filtered agglomerate was very low, 0.002% of the total monomer. The obtained aqueous emulsion had a nonvolatile content of 50%, an average particle diameter of 120 nm, and a Tg value of 4 ° C.

(Comparative Example A-3) Methyl methacrylate was added to 3
3.0 parts, except that butyl acrylate was 0.8 parts,
It carried out by the same operation as Example A-1. The dry weight of the filtered agglomerate was very low, 0.002% of the total monomer. The resulting aqueous emulsion had a nonvolatile content of 5
0%, the average particle diameter was 160 nm, and the Tg value was 85 ° C.

(Comparative Example A-4) The same operation as in Example A-1 was performed except that 1.2 parts of Eleminor JS-2 charged in the four-necked flask in the second stage was used. In this case, a stable emulsion was not obtained.

(Comparative Example A-5) Except that 0.9 parts of Eleminol JS-2 used in the first stage and 0 parts of Eleminol JS-2 charged in a four-necked flask in the second stage were used.
It carried out by the same operation as Example A-1. The dry weight of the filtered agglomerate was as low as 0.005% based on all monomers. The nonvolatile content of the obtained aqueous emulsion is 50%,
The average particle size was 290 nm, and the Tg value was 41 ° C. Table 1 shows the composition and properties of the above Examples A-1 to A-5 and Comparative Examples A-1 to A-5 in the synthesis.

[0031]

[Table 1]

Next, a specific example of the composition of the aqueous coating composition of the present invention will be described. [Preparation of water-based paint composition] (Examples 1-1 to 1-5, Comparative Examples 1-1 to 1-5) Preparation of a water-based paint was carried out as a first step, with a diameter of 10 cm and height of 1
Deionized water: 30 g in a 5 cm stainless steel beaker,
0.3 g of SN Deformer 485 (manufactured by San Nopco), 0.3 g of 25% ammonia water and 3.6 g of Nopcospar 44C (manufactured by San Nopco) are added as defoaming agents, and a disper equipped with a stirring blade having a diameter of 5 cm. 1 using
Black 3 as an inorganic pigment while stirring at 000 rpm.
58 g of 90H (manufactured by Toda Kogyo Co., Ltd., black iron oxide pigment), silica powder, and 7.8 g of Sylysia 350 (manufactured by Fuji Silysia Chemical Ltd.) were added. After the addition, the rotation speed of the stirring blade is set to 400.
The mixture was stirred at 0 rpm for 30 minutes to obtain a pigment dispersion. Next, as a second step, a diameter of 10 cm and a height of 15 c
m-a stainless steel beaker was charged with 79 g of the pigment dispersion obtained in the first step, and stirred at 700 rpm using a disper equipped with a stirring blade having a diameter of 5 cm.
1 to A-5, 205 g of Comparative Examples A-1 to A-5, 6 g of butyl cellosolve, 3 g of Texanol, 23 g of deionized water
After stirring for 10 minutes, 25 g of a 2% aqueous solution of hydroxyethylcellulose and 8 g of deionized water were added as a thickener, and the mixture was further stirred for 1 hour. The obtained paint was allowed to stand at room temperature for 1 day. It was used as a paint for various tests. Table 2 shows the composition.

A test piece was prepared from the coating composition obtained as described above by the following method, and the weather resistance, hot water whitening resistance, hot water whitening resistance and freeze-thaw adhesion to the substrate of the coating film were prepared. The test was performed. Table 2 shows the results.

(Preparation of test piece)
A paint sample diluted 10% with deionized water was spray-coated, dried at 120 ° C. for 3 minutes, and then cured for 7 days at 20 ° C. and 65% relative humidity to obtain a target test piece. Use a JIS flexible board as the slate board, and apply 150 g of paint sample.
/ M ² . (Test method for coating film) Accelerated weather resistance Using the above test piece, an accelerated test was performed for 2,000 hours by a super UV tester, and the color difference (Δ
E) and gloss retention (%) were measured. 2. Initial adhesion test (JIS K5400) Using the above-described test piece, a grid test specified in JIS K5400 was performed. Judgment standard is JIS K5
It is rated on a scale of 10 out of 10 according to 400. 3. Freeze-thaw adhesion test According to ASTM-C666A using the test piece described above, the film was subjected to a 200-cycle repetition test in which 2.5 hours of immersion in water at 10 ° C and 2.5 hours of freezing in water at -20 ° C were used as one cycle. Is visually determined. The criteria are as follows. 5 points: No change 4 points: Slight floating and swelling of the film are observed 3 points: Floating and swelling of the film are observed 2 points: Peeling of the film is observed 1 point: Peeling of the coating film is observed over the entire surface 4. Warm water resistance test method The test piece is immersed in deionized water at 50 ° C for 20 days, taken out of the water, quenched with cold water, and the degree of whitening of the film is visually determined. The criteria are as follows. 5 points: No change, no swelling, no peeling 4 points: Slightly whitened, but no swelling, no peeling 3 points: Slightly whitened, partially swelled, peeled 2 points: Whitened 4. Observed, swelling and peeling were observed in one part. 1 point: The entire surface was whitened, and swelling and peeling were observed. Hot water resistance test method The test piece is immersed in deionized water at 90 ° C for 2 hours, taken out and quenched with cold water, and the degree of whitening of the film is visually determined. The criteria are as follows. 5 points: No change, no swelling, no peeling 4 points: Slightly whitened, but no swelling, no peeling 3 points: Slightly whitened, partially swelled, peeled 2 points: Whitened Recognized, partly swollen and peeled off One point: The entire surface is whitened, and swollen and peeled off

[0035]

[Table 2]

[0036]

According to the aqueous coating composition using the resin dispersion of the present invention, a coating film excellent in weather resistance, freeze-thaw adhesion, hot water whitening resistance and hot water whitening resistance can be obtained. Furthermore, it can be manufactured industrially easily and inexpensively with ordinary manufacturing equipment and manufacturing conditions.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C09D 125/02 C09D 125/02 133/04 133/04 139/04 139/04 F-term (Reference) 4J011 AA05 BA03 DA01 KA06 KA14 KB08 KB14 KB29 4J027 AC01 AC02 AC06 BA02 BA05 BA06 BA07 BA08 BA09 BA10 BA12 BA13 BA15 CB02 CB03 CB09 CC02 CD08 4J038 CC021 CC071 CG141 CH031 CH041 CH071 CH121 GA171 CK01 HA031 HA536 HA546 KA08 MA08 MA10 MA13 MA14 NA03 NA04 NA12 PB05 PC01

Claims (3)

[Claims] An α, β-ethylenically unsaturated monomer (a) containing a polyethylene glycol-polypropylene glycol block copolymer represented by the following formula (i):
0.01 to 5% by weight, α, β-ethylenically unsaturated monomer (b) 85 to 99.94% by weight, and monomer (a)
Other hydrophilic α, β-ethylenically unsaturated monomers (c)
0.05 to 10% by weight (provided that the total of (a) to (c) is 100% by weight) in the presence of a surfactant (e) having a radically polymerizable functional group, An aqueous dispersion of a resin (p) obtained by emulsion copolymerization using a radical polymerization initiator in a medium, comprising a monomer (a),
(B) and resin (p ') assuming that it consists of (c)
Has a glass transition point Tg value of 20 to 80 ° C. calculated by the FOX formula, and the resin (p) has a particle size of 50 to 25.
Aqueous resin dispersion dispersed at 0 nm. Embedded image (Wherein, R is a hydrogen atom or a methyl group, and m and n are 1 to 20)
Represents an integer. ) 2. An aqueous coating composition for an inorganic building material, comprising a mixture of the aqueous resin dispersion according to claim 1 and a pigment dispersion. 3. The performance of a coating film obtained from the aqueous coating composition for an inorganic building material is evaluated according to a predetermined test method, and the gloss retention by accelerated weather resistance is 80% or more, and the freeze-thaw adhesion is 4%.
3. The aqueous coating composition for inorganic building materials according to claim 2, wherein the hot water whitening resistance is 4 or more, and the hot water whitening resistance is 4 or more.