JP3378821B2 - Aqueous quick-drying paint composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based coating composition having quick-drying property, and more specifically, it has excellent coating stability.
The present invention relates to a water-based quick-drying coating composition in which odor generated from a coating is reduced and which has excellent durability and weather resistance after forming a coating film.

[0002]

2. Description of the Related Art In recent years, the release of volatile organic solvents into the atmosphere due to the application of solvent-type paint has been highlighted as an environmental problem. In response to this, in order to reduce the emission of volatile organic solvents, conversion from solvent-based paints to water-based paints is in progress. However, water-based paints are not sufficiently dry-curable compared to solvent-based paints, and especially in a low temperature environment, it takes a considerable amount of time for the paint film to completely cure. If there is, there is a problem such as the coating film flowing out.

In order to solve this problem, a method of increasing the evaporation rate of the solvent contained in the paint has been proposed. Specifically, a method of adding a low boiling point solvent such as methanol to the water-based resin coating material may be used. According to this method, the drying speed is higher than that of a general water-based resin coating material, but when water comes into contact with the coating film in the initial stage of drying, the coating film may flow out. Also, since it is necessary to add a large amount of low boiling point solvent, despite being a water-based paint,
In some cases, there was a danger of being flammable.

As another method for solving the problem, a method based on a gelation reaction of an aqueous resin has been proposed. This method has a mechanism in which a reactive group and a group capable of reacting with the reactive group are allowed to coexist in the water-based paint, and gelation proceeds immediately after the coating film is formed. That is, by increasing the evaporation rate of water as a solvent, rather than forming a gel structure in the resin in the water-based coating, even if water comes into contact with the coating in the initial stage of coating formation, the outflow of the coating It does not happen. It can be understood that the process of dry curing includes a first step of gelling while containing water and a second step of gradually evaporating and hardening water.

As an application of this method, Japanese Unexamined Patent Publication No.
-157463 can be mentioned. The invention discloses a technique of introducing an amine-containing aqueous polymer and a base into an anionic synthetic resin emulsion. This aqueous coating composition has a function of preventing the coating film from flowing out even when contacted with water in the initial stage of drying.

[0006]

However, no consideration is given to the physical properties of the coating film after the coating film has been dried and cured. That is, the dry-cured coating film obtained by this method does not have sufficient durability and weather resistance, and has a problem that it causes deterioration of gloss over time and the initial appearance cannot be retained. .

Further, since the amine-containing water-based polymer has a cationic property, in a system in which the amine-containing water-based polymer is introduced into an anionic synthetic resin emulsion, the generation of foreign matters and the increase of viscosity over time are caused. There was a problem, and it was a subject to secure sufficient paint stability.
Although the storage stability can be improved by adding an excessive amount of base, in this case, the odor of the base is strongly generated from the paint, which causes a problem in the working environment.

[0008] Therefore, the problem to be solved by the present invention is that it has fast drying property, has excellent storage stability that exhibits water resistance from the initial stage of drying, and has excellent durability and weather resistance with less odor generated. In addition, it is an object of the present invention to provide a water-based quick-drying coating composition that can retain the appearance such as gloss in a glossy coating for a long period of time and can solve all of these problems.

[0009]

In order to solve these problems, the present inventor has conducted extensive studies, and as a result, a specific surfactant and a specific amine-containing aqueous resin are stabilized by an anionic functional group. The coating composition introduced into the liquefied aqueous resin dispersion has excellent storage stability, the odor generated from the coating is reduced, and since it has quick-drying properties when the coating film is formed, it can exhibit water resistance from the initial stage of drying. The inventors have found that they can be formed, have excellent durability and weather resistance after forming a coating film, and can retain the appearance such as gloss for a long period of time, and have completed the present invention.

That is, the present invention is as follows: In paint the aqueous resin dispersions stabilized by anionic functional group as a main binder, (A) Poria
An aqueous quick-drying coating composition comprising an aqueous resin selected from rilamine and polyethyleneimine , and (B) an anionic surfactant having an alkylene oxide group. 2. 1. The weight average molecular weight of (A) is 500 to 15,000. The water-based quick-drying coating composition according to. 3. The number of repeating alkylene oxide groups of (B) is 1
1. It is 0 or more. Or 2. The water-based quick-drying coating composition according to.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The amine-containing aqueous resin (A) used in the present invention imparts quick-drying properties when forming a coating film, and further imparts sufficient durability and weather resistance to the coating film after formation, It is an essential component for maintaining the appearance such as gloss for a long period of time, and it is essential that the composition has a unit structure represented by the general formula [1] and / or [2].

Examples of the water-soluble resin (A) include polyallylamine and polyethyleneimine.

The weight average molecular weight of (A) is 500 to 15
It is preferably 000. When it is less than 500, the durability and weather resistance of the coating film tend to decrease. 15
If it is more than 000, the gloss tends to be low in the curing process, and it becomes difficult to obtain sufficient gloss. In addition, the stability of the coating also shows a tendency toward instability.

The amount of (A) added is not particularly limited, but considering the balance of quick drying property, durability and weather resistance, it is 0.2 to 10 relative to the solid content of the aqueous resin dispersion.
% (Solid content) is preferable. If it is less than 0.2%, the quick-drying property tends to decrease. 10%
When it is more, the durability and weather resistance tend to decrease.

The anionic surfactant (B) having an alkylene oxide group is used for the generation of foreign matter in the coating,
It is an effective component for suppressing the increase of viscosity with time and for maintaining the durability and weather resistance of the dry-cured coating film. Examples of the group imparting anionic property include a carboxylate salt, a sulfate ester salt, a sulfonate salt, and a phosphate ester salt.

Examples of the alkylene group of the alkylene oxide group include an ethylene group, a propylene group, a butylene group and an isobutylene group. It is preferable that the number of repeating alkylene oxides is 10 or more, because the coating stability is improved. Further, from the viewpoint of durability and weather resistance, a form having a reactive double bond and being incorporated in the resin skeleton during polymerization is preferable.

The addition amount of (B) is preferably 1 to 6% with respect to the resin content of the aqueous resin dispersion. If it is less than 1%, the storage stability tends to decrease. When it is more than 6%, quick-drying property and water resistance tend to be lowered.

(B) can be used alone, but within a range that does not impair weather resistance, durability, or paint stability,
It is also possible to use together with one kind or two or more kinds of other anionic surfactants, nonionic surfactants, cationic surfactants and amphoteric surfactants.

The aqueous resin dispersion which is the main binder of the coating composition of the present invention is not particularly limited as long as it is an aqueous resin dispersion in which an anionic functional group is dissociated by a base and stabilized. As the type of resin, acrylic resin,
Examples thereof include acrylic styrene resin, acrylic urethane resin, acrylic silicon resin, and fluorine resin.

The base that dissociates the anionic functional group of the aqueous resin dispersion also contributes to the stabilization of the amine-containing aqueous resin (A). Furthermore, this base volatilizes after forming the coating film,
It also plays the role of promoting the reaction between the anionic functional group of the aqueous resin dispersion and the amino group of (A). Examples of the type of base include ammonia, monoethylamine, diethylamine, triethylamine, isopropylamine, diisopropylamine, and the like, but ammonia is preferably used because it exhibits excellent quick-drying properties.

Generally, in a water-based paint having a mechanism in which an anionic functional group and an amino group react with each other, when the amino group is cationized in the paint, a foreign substance is generated due to the reaction with the anionic functional group, and the viscosity of the paint. Causes a significant increase. In order to solve this problem, dehydrogenation of the amino group, that is, nonionization may be performed.
Stabilization can be achieved by adding an excessive amount of base to the paint. However, in paints that use this method,
Since the strong odor of the base is generated, there is a problem in that the work particularly at the time of painting becomes difficult and the surrounding environment is also adversely affected.

On the other hand, in the present invention, since it was found that a specific amine-containing aqueous resin and a specific anionic surfactant are combined, it is not necessary to keep the state where the amino group is completely nonionic. Also, it is not necessary to add an excessive amount of base. The odor generated from the paint is also reduced to the same extent as the water-based paint that is normally used. It is considered that the mechanism by which the storage stability of the coating composition of the present invention is maintained is largely related to the steric hindrance effect of the alkylene oxide group of the anionic surfactant (B).

Regarding the reaction mechanism of the water-based quick-drying coating composition of the present invention, the following mechanism can be assumed. 1) Immediately after the coating of the paint, the base of the aqueous resin dispersion volatilizes and the pH drops. 2) Hydrogenation of the amino group of (A) is promoted and the cation charge is increased. 3) The ionic interaction between the hydrogenated amino group of (A) and the anionic functional group of the aqueous resin dispersion becomes stronger,
Causes gelation. 4) Water gradually evaporates and curing proceeds.

The anion portion of (B) is protected by the steric hindrance effect of the alkylene oxide group of (B) before forming the coating film, but after forming the coating film, the hydrogenated amino group of (A) is protected. By the ionic action with the group, the resin is firmly incorporated in the formed resin. Therefore, the durability and weather resistance of the formed coating film are not reduced.

The water-based quick-drying coating composition of the present invention may contain, if necessary, a solvent, a pigment and the like which are usually used in coating materials, as long as the effects of the invention are not impaired.

As the solvent, methanol, ethanol,
Propanol, isopropyl alcohol, alcohols such as benzyl alcohol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylolethane, polyhydric alcohols such as glycerin, cellosolve, butyl cellosolve, isobutyl cellosolve, carbitol, methyl carbitol, Examples thereof include ethers such as butyl carbitol and propylene glycol monomethyl ether, and esters such as 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate.

Examples of pigments include inorganic materials such as titanium oxide, zinc oxide, carbon black, ferric oxide (red iron oxide), lead chromate (molybdate orange), yellow lead, yellow iron oxide, ocher, ultramarine blue and cobalt green. Pigment, azo,
Organic pigments such as naphthol, pyrazolone, anthraquinone, perylene, quinacridone, disazo, isoindolinone, benzimidazole, phthalocyanine, and quinophthalone can be used. It is also possible to use extender pigments such as heavy calcium carbonate, clay, kaolin, talc, precipitated barium sulfate, barium carbonate, white carbon and diatomaceous earth.

Further, a plasticizer, an antiseptic, an antifungal agent, an antifoaming agent,
Leveling agent, pigment dispersant, anti-settling agent, anti-sagging agent,
Additives such as an ultraviolet absorber and an antioxidant can be blended alone or in combination.

The water-based quick-drying coating composition of the present invention comprises a topcoat paint, a multi-layer coating material main material, a waterproof multi-layer coating material main material, a thick finish coating material, and a thin finish coating material according to a known formulation. It can be used as a paint in any form such as a single-layer elastic coating material.

The aqueous coating composition of the present invention comprises metal, glass, porcelain tile, concrete, siding board,
It can be used for surface finishing of various materials such as extruded plates and plastics, and is mainly used for protecting the skeleton of buildings, civil engineering structures, etc. At this time, the water-based quick-drying coating composition of the present invention can be directly applied to a substrate, or can be applied after being subjected to some kind of surface treatment (base treatment, etc.), but is not particularly limited. Not something. As a coating method, various methods such as brush coating, spray coating, roller coating, roll coater and flow coater can be used. Furthermore, the surface of the building material can be pre-coated in a factory or the like.

[0031]

EXAMPLES Examples and comparative examples will be shown below to further clarify the characteristics of the present invention.

(1) Preparation of coating material An aqueous resin dispersion containing the monomers and the surfactant shown in Table 1 and the amine-based aqueous resin shown in Table 2 were used to prepare Tables 3 and 4.
A paint was prepared with the composition shown in.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

(2) Test Method Odor The odor generated from the prepared coating composition was evaluated by a sensory test. The evaluation is as follows. ◯: Almost no odor is felt ×: Remarkably odor is felt

Storage stability The prepared coating composition was stored in a constant temperature bath at 50 ° C. for 7 days,
The change in viscosity was confirmed. The evaluation is as follows. A: Viscosity change less than 10% O: Viscosity change 10% to less than 20% B: Viscosity change 20% to less than 30% X: Viscosity change 30% or more

Quick-drying The prepared coating composition was applied at 20 ° C. and 65% RH (hereinafter, referred to as “standard state”) on a 150 × 120 × 3 mm transparent glass plate so that the WET film thickness was 150 μm. When the film was pulled out and immersed in water, the time until the coating film did not flow out was measured.

Water resistance The prepared coating composition was applied to a transparent glass plate of 150 × 120 × 3 mm by an applicator so that the WET film thickness would be 150 μm, and dried and cured in a standard state for 2 days, then 50
The change in gloss was confirmed after immersion in warm water at ℃ for 5 hours. The gloss is 6 according to JIS K5400 7.6 specular gloss.
The gloss at an angle of 0 degree was measured. The evaluation is as follows. ◯: Gloss retention rate 80% or more B: Gloss retention rate 70% or more and less than 80% X: Gloss retention rate less than 70%

Accelerated weather resistance 150 × 70 × 3 mm flexible plate was spray-coated with Mirax Sealer W (special modified resin water-based sealer; manufactured by SK Kaken Co., Ltd.) at a coating amount of 0.1 kg / m ^{2 to} obtain a standard. It was dried in the state for 2 hours. Next, the prepared coating composition was spray coated at a coating amount of 0.3 kg / m ² to prepare a test body. The produced test body was dried and cured for 14 days in a standard state, and then an accelerated weather resistance test was performed using a sunshine weather meter specified in JIS B 7753, and a change in gloss after 500 hours was confirmed. The evaluation is as follows. ◯: Gloss retention rate 80% or more B: Gloss retention rate 70% or more and less than 80% X: Gloss retention rate less than 70%

(3) Test result The test results are shown in Table 5.

[Table 5] (Examples 1 to 5) Not only excellent quick-drying property but almost no odor, resulting in excellent storage stability, water resistance and accelerated weathering resistance. (Comparative Examples 1 and 2) When the amine-based water-soluble resin of the present invention was not used, storage stability was not obtained unless the pH was increased, and the water resistance and accelerated weather resistance were inferior. (Comparative Examples 3 to 4) When the anionic surfactant did not contain an alkylene oxide group, the storage stability was poor. (Comparative Example 5) When the amine-based water-soluble resin was not contained, quick drying could not be obtained.

[0039]

The aqueous quick-drying coating composition of the present invention is obtained by introducing a specific surfactant and a specific amine-containing aqueous resin into an aqueous resin dispersion liquid stabilized with an anionic functional group. It has excellent storage stability, the odor generated from the paint is reduced, and it has a quick-drying property when the coating film is formed, so that it can exhibit water resistance from the initial stage of drying, and also has durability and weather resistance after the coating film is formed. Excellent in appearance and capable of maintaining the appearance such as gloss for a long period of time.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C09D 139/02 C09D 5/02 C09D 157/10 C09D 157/12

Claims (3)

(57) [Claims] 1. A paint comprising an aqueous resin dispersion liquid stabilized with an anionic functional group as a main binder, comprising: (A) an aqueous resin selected from polyallylamine and polyethyleneimine ; (B) an anion having an alkylene oxide group. A water-based quick-drying coating composition, characterized by containing a surface active agent. 2. The weight average molecular weight of (A) is 500 to 150.
It is 00, The water-based quick-drying coating composition of Claim 1. 3. The water-based quick-drying coating composition according to claim 1 or 2, wherein the repeating number of the alkylene oxide group of (B) is 10 or more.