JPH09316389A - Water-based coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-based coating composition nonproblematic in whitening and excellent in mechanical stability and storage stability by using a water- dispersible resin prepared by emulsion-polymerizing a specified monomer in the presence of a reactive emulsifier as the binder. SOLUTION: A water-dispersible resin obtained by emulsion-polymerizing a monomer component consisting essentially of a monoethylenically unsaturated carboxylic alkyl ester and an ethylenically unsaturated carboxylic acid in the presence of a reactive emulsifier having a sulfonic group and an ethylenic unsaturation in a molecular structure and a colored aggregate are used as the essential components to obtain a water-based coating composition. When dried, the above water-dispersible resin forms a substantially colorless transparent coating film. Therefore, the above water-based coating composition can fully utilize the color, shape, etc., of the fine aggregate used and is effective for the protection or decorative finish of the surface of the ground of a structure (wall, roof or floor).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a structure (wall, roof, floor, etc.) of a water-dispersible resin that forms a colorless and transparent film when dried and makes full use of the color, shape and the like of the fine granules used. ) The present invention relates to an aqueous coating composition which protects the ground and is effective for cosmetic finishing.

[0002]

2. Description of the Related Art Conventionally, as a surface protection for structures (walls, roofs, floors, etc.) and as a decorative material, flat paint or lysine paint,
Sprayed tile (crater shape, uneven shape), stucco,
Roller pattern paints have been used.

Although organic or inorganic pigments are generally used as colorants in such coating materials, these coating materials have a problem that the color tone is monotonous and lacks a high-class feeling.

Therefore, an aqueous coating composition composed of a binder and a coloring material is used as a coating material that exhibits a deep and subdued color tone close to that of natural stone typified by marble, and is inexpensive and applicable to simple construction. Have been proposed and put to practical use.

Specifically, such a coating material uses, as a binder, a water-dispersible resin that forms a substantially colorless and transparent film when dried, and uses a fine aggregate such as natural stone or ceramics as a coloring material. It is used and can be finished with a spray or iron.

[0006]

However, the water-dispersible resin used in these coating materials causes a whitening phenomenon due to rain or water during washing, especially when it is raining at high temperature in summer, and the original color of the colored aggregate. However, there is a problem that the shape and the like are dim and the appearance is unsightly.

To avoid this, a method of reducing the amount of the surfactant used when preparing the water-dispersible resin has been reported. However, in this method, there was a problem that the mechanical stability of the water-dispersible resin was poor due to the reduction in the amount of the surfactant, and the spray coating suitability and the storage stability in the case of long-term storage were poor.

The problem to be solved by the present invention is to provide an aqueous coating composition which is unlikely to be bleached in water or warm water and which is excellent in mechanical stability and storage stability.

[0009]

Therefore, the inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, water-dispersibility obtained by emulsion polymerization of a specific monomer component as a binder using a reactive emulsifier. By using a resin, it was found that the whitening phenomenon was solved and the mechanical stability and long-term storage stability were excellent, and the present invention was achieved.

That is, according to the present invention, a monoethylenically unsaturated carboxylic acid alkyl ester and a monomer component containing an ethylenically unsaturated carboxylic acid as an essential component are used as a sulfone group or a sulfate group and an ethylenically unsaturated group. The present invention relates to an aqueous coating composition, which comprises, as essential components, a water-dispersible resin obtained by emulsion polymerization in the presence of a reactive emulsifier having in the molecular structure thereof and a colored bone agent.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The water-dispersible resin used in the present invention is
Monoethylenically unsaturated carboxylic acid alkyl ester and a monomer component containing ethylenically unsaturated carboxylic acid as an essential component, a reactive emulsifier having a sulfone group or a sulfate group and an ethylenically unsaturated group in its molecular structure. It is obtained by emulsion polymerization in the presence of.

The monoethylenically unsaturated carboxylic acid alkyl ester used here is not particularly limited, but for example, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylic acid. 2-ethylhexyl, decyl acrylate, dodecyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, dodecyl methacrylate. Alternatively, 2-hydroxyethyl methacrylate or the like can be used.

Further, in the present invention, weather resistance can be further improved by using an aromatic vinyl monomer together with the above-mentioned monoethylenically unsaturated carboxylic acid alkyl ester. Such an aromatic vinyl monomer is not particularly limited, but examples thereof include styrene, α-methylstyrene, P-tert-butylstyrene, vinyltoluene and the like.

The above-mentioned monoethylenically unsaturated carboxylic acid is not particularly limited, but examples thereof include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid and the like. Of these, acrylic acid and methacrylic acid are preferable from the viewpoint of dispersion stability.

The ratio of the above-mentioned monomer components to be used is not particularly limited, but from the viewpoint of long-term storage stability, the amount of ethylenically unsaturated carboxylic acid used in all the monomer components is
It is preferably 0.1 to 5.0% by weight based on the total weight of the monomer components.

In addition to these monomers, for example,
Like divinylbenzene or divinyl acrylate,
So-called crosslinkable monomers (crosslinking agents) may be used.

As a method for producing a water-dispersible resin by emulsion polymerization of the above-mentioned monomer components, a reactive emulsifier having a sulfone group or a sulfate group and an ethylenically unsaturated group in its molecular structure is used as an emulsifier. However, there is no particular limitation.

The reactive emulsifier capable of copolymerization containing the sulfone group or the sulfate group and the ethylenically unsaturated group in the same molecule is not particularly limited, but for example, a propenyl group-introduced type of polyoxyethylene alkylphenyl sulfate, Examples thereof include an allyl group-introduced type of polyoxyethylene alkylphenyl ether and a vinyl group-introduced type of dialkylsulfosuccinate.

The amount used is not particularly limited, but is 0.1 to 5.0% by weight based on the total monomer components.
From the viewpoint of whitening prevention, it is preferable that the range is

The colored aggregate is not particularly limited, and examples thereof include natural colored sand such as black cold water stone, serpentine, and fluorite, and artificial colored sand such as ceramic crushed grains and calcined silica sand.

The water dispersible resin is preferably used in an amount of about 2 to 50% based on the total solid content of the coating composition. If it is 2% or more, the strength of the coating layer formed is excellent and cracks and the like can be prevented, while if it is 50% or less, the drying property is good.

As a method for applying the coating composition of the present invention on the ground surface, for example, a spraying method and a trowel coating method are suitable. Both of the construction methods generally include a step of depositing a coating composition prepared in advance in a predetermined color tone and superimposing a coating composition having a different color tone on the coating composition in spots. However,
In the case of the non-speckled type, the step of overlapping the coating compositions having different color tones in a speckled manner may be omitted. Further, if a gloss is to be obtained as necessary, a transparent resin solution is applied or sprayed.

It forms a nearly colorless and transparent film when dried, and since it is used outdoors, it has excellent weather resistance,
It must have excellent resistance to warm water whitening.

[0024]

EXAMPLES The coating composition of the present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Reference Example 1 (Production of Carboxyl Group-Containing Water-Dispersible Resin A-1 Using Reactive Emulsifier) Deionized water 35 was added to a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel. Then, the temperature was raised to 80 ° C. while blowing nitrogen. Under stirring, 0.1 part of sodium persulfate was added, followed by 21 parts of 2-ethylhexyl acrylate, 26.9 parts of methyl methacrylate, 1 part of acrylic acid, Aqualon HS-1025 (Daiichi Kogyo Seiyaku Co., Ltd.); Polyoxyethylene alkylphenyl ether ammonium salt with reactive groups: solid content 25%) 4
Part and 10 parts of deionized water were added dropwise over 150 minutes while maintaining the internal temperature of the reaction vessel at 80 ± 3 ° C. for polymerization. After completion of dropping, the mixture was stirred at the same temperature for 30 minutes, and the pH of the content was adjusted to 8.0 with aqueous ammonia. Then, the content was cooled, adjusted to a solid content concentration of 50.0% with deionized water, and filtered through a 100-mesh wire net. Aggregate that does not pass through 100 mesh is 0.1%
(Ratio to generated dispersion liquid) or less. The aqueous dispersion of this carboxyl group-containing polymer is designated as A-1.

Reference Example 2 (Production of Carboxyl Group-Containing Water-Dispersible Resin A-2 by Using Reactive Emulsifier) Deionized water 35 was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel. Then, the temperature was raised to 80 ° C. while blowing nitrogen. With stirring, 0.1 part of sodium persulfate was added, followed by 21 parts of 2-ethylhexyl acrylate, 16.9 parts of methyl methacrylate, 10 parts of styrene, 1 part of acrylic acid, Aqualon HS-1025.
(Manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd .; polyoxyethylene alkylphenyl ether ammonium salt having a reactive group: solid content 25%) 4 parts, and a monomer mixture consisting of 10 parts of deionized water was heated at a reaction container internal temperature of 80. While keeping the temperature at ± 3 ° C, the mixture was added dropwise over 150 minutes for polymerization. After completion of dropping, the mixture was stirred at the same temperature for 30 minutes, and the pH of the content was adjusted to 8.0 with aqueous ammonia.

After that, the content is cooled to a solid content of 5
It was adjusted to 0.0% with deionized water and filtered through a 100-mesh wire net. Aggregates that did not pass through the 100-mesh wire net were 0.1% or less (ratio to generated dispersion liquid).

The aqueous dispersion of the carboxyl group-containing polymer is designated as A-2.

Reference Example 3 (Production of carboxyl group-free water-dispersible resin A-3 using a reactive emulsifier) Deionized water was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer and a dropping funnel. 35 parts was added and the temperature was raised to 80 ° C. while blowing nitrogen. While stirring, 0.1 part of sodium persulfate was added, followed by 21 parts of 2-ethylhexyl acrylate, 27.9 parts of methyl methacrylate, and Aqualon HS-1025 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd .; polyoxyethylene alkylphenyl). A monomer mixture consisting of 4 parts of an ether ammonium salt (having a reactive group) and 10 parts of deionized water was added dropwise over 150 minutes to carry out polymerization while maintaining the temperature in the reaction vessel at 80 ± 3 ° C. 30 at the same temperature after dropping
After stirring for a minute, the pH of the contents was adjusted to 8.0 with aqueous ammonia. After that, the contents are cooled to a solid content of 5
It was adjusted to 0.0% with deionized water and filtered through a 100-mesh wire net. Aggregates that did not pass through the 100-mesh wire net were 0.1% or less (ratio of body-forming dispersion liquid).

An aqueous dispersion of this carboxyl group-containing polymer is designated as A-3.

Reference Example 4 (Production of carboxyl group-containing water-dispersible resin A-4 by using non-reactive emulsifier) Deionized water was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer and a dropping funnel. 35 parts was added and the temperature was raised to 80 ° C. while blowing nitrogen. With stirring, 0.1 part of sodium persulfate was added, followed by 21 parts of 2-ethylhexyl acrylate, 26.9 parts of methyl methacrylate, 1.0 part of acrylic acid, Rebenol WZ (manufactured by Kao Corporation; polyoxyethylene). A monomer mixture consisting of 8 parts of sodium alkylphenyl ether sulfonate, solid content 25%) and 10 parts of deionized water was added while keeping the temperature in the reaction vessel at 80 ± 3 ° C.
The mixture was added dropwise over 0 minutes for polymerization. After completion of dropping, the mixture was stirred at the same temperature for 30 minutes, and the pH of the contents was adjusted to 8. with ammonia water.
Adjusted to zero. Then, the content was cooled, adjusted to a solid content concentration of 50.0% with deionized water, and filtered through a 100-mesh wire net. Aggregates that did not pass through the 100-mesh wire net were 0.1% or less (ratio of body-forming dispersion liquid).

An aqueous dispersion of this carboxyl group-containing polymer is designated as A-4.

The physical properties of the polymer aqueous dispersions and clear films of Reference Examples 1 to 4 above were measured and the results are shown in the table below.

[0034]

[Table 1]

Evaluation method: (Water whitening resistance) The aqueous polymer dispersions A-1 to A-4 obtained in Reference Examples 1 to 4 were coated on a glass plate with a 3 mil applicator and dried at room temperature for 3 days. To form a film. After that, a heat treatment was performed at 120 ° C. for 5 minutes to evaporate the remaining water to obtain a test piece. The test piece was immersed in normal temperature water for 7 days, and the deterioration (whitening) state of the test piece before and after the water immersion was evaluated in three stages.

[0036]

(Mechanical Stability) The polymer aqueous dispersions A-1 to A-4 obtained in Reference Examples 1 to 4 were placed in a Marlon tester under the conditions of a rotation speed of 1000 rpm and a time of 10 minutes. .
The generation rate of aggregates (relative to solid content%) generated at that time was evaluated.

(Storage stability) The polymer aqueous dispersions A-1 to A-4 obtained in Reference Examples 1 to 4 were left at 50 ° C. for 30 days, and the change in viscosity of the dispersions before storage was β. It was measured with a viscometer and evaluated in four levels.

Criteria: ○ Initial viscosity and viscosity change after 30 days no change △ Initial viscosity and viscosity change rate after 30 days within 50% × Initial viscosity and viscosity change rate after 30 days 50% or more, or gelation

Examples 1 and 2 and Comparative Examples 1 and 2 Using the above water-dispersible resins A-1 to A-4, the following second
The paint formulations were prepared according to the table.

[0041]

[Table 2]

Next, the physical properties of the obtained paint and coating composition were evaluated by the following methods. The results are shown in Table 3.

Evaluation Method of Paint Blends (Water Whitening Resistance of Coating) Blends 1 to 5 obtained by the above blending recipe are sprayed uniformly on a slate plate with a spray gun and dried at room temperature for 14 days to form a coating. did. Then one
A heat treatment was carried out at 20 ° C. for 5 minutes to evaporate the remaining water to obtain a test piece. The test piece was immersed in normal temperature water for 7 days, and the deterioration (whitening) state of the test piece before and after the water immersion was evaluated in three stages.

[0044]

(Storage stability) The viscosity change of each of the formulations 1 to 5 obtained by the above formulation after standing at 50 ° C. for 30 days was measured with a Stomer viscometer and evaluated in three stages.

Criteria: ○ Initial viscosity and no viscosity change after 30 days △ Initial viscosity and viscosity change rate within 30 days within 50% × Initial viscosity and viscosity change rate after 30 days 50% or more, or gelation

[0047]

[Table 3] As shown in Table 3, the coating composition of the emulsion dispersion obtained by the method of the present invention is more stable than the coating composition of the emulsion dispersion using an ordinary emulsifier, and the coating composition has a water-whitening resistance. It turns out to be excellent.

[0048]

According to the present invention, it is possible to provide an aqueous coating composition which is unlikely to be whitened by water or warm water, and which is excellent in mechanical stability and storage stability.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area C09D 133/02 PFW C09D 133/02 PFW // C08F 2/24 MCB C08F 2/24 MCB

Claims (4)

[Claims] 1. A monoethylenically unsaturated carboxylic acid alkyl ester and a monomer component containing an ethylenically unsaturated carboxylic acid as an essential component, a sulfone group or a sulfate group, and an ethylenically unsaturated group in the molecular structure. An aqueous coating composition, which comprises a water-dispersible resin obtained by emulsion polymerization in the presence of the reactive emulsifying agent and a colored bone agent as essential components. 2. The composition according to claim 1, which further contains an aromatic vinyl monomer as a monomer component. 3. The amount of ethylenically unsaturated carboxylic acid used is 0.1 to 5.0% by weight based on the total weight of the monomer components.
The composition according to claim 1 or 2, which is 4. The amount of the reactive emulsifier used is 0.1 to 5.0% by weight based on the total weight of the monomer components.
The composition according to 2 or 3.