JP2002186900A - Antifoulancy coating film and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating film which has excellent antifoulancy. SOLUTION: The coating film is composed of an undercoat coating film layer formed from a coating (A) containing a compound having a silanol group or a compound producing a silanol group by hydrolysis and a finish coat coating film layer formed from a water base coating (B) containing an acrylic-silicone resin. The content of the compound having a silanol group or the compound producing a silanol group by hydrolysis in the coating (A) is 1-50 wt.%, and the acrylic-silicone resin is an emulsion resin in which 40-60 wt.% of an acrylic resin and 40-60 wt.% of a silicone resin are combined into a hybrid resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating film comprising an undercoat film layer and an overcoat film layer applied to the surface of various substrates, and a method for molding the same. The two-layered coating film of the present invention is remarkably excellent in stain resistance.

[0002]

2. Description of the Related Art In recent years, fluorine paints, urethane paints, and the like have been developed for buildings such as houses and high-rise buildings, or structures such as tunnels and bridges for the purpose of protecting the surface and imparting designability to the surface. Painting with an organic solvent-based paint such as acrylic urethane paint is performed. When these paints are used, since a coating film having excellent weather resistance is formed, it is possible to improve the surface durability,
On the other hand, it has been pointed out that coating films made of these paints have a problem of stain resistance.

[0003] In order to improve the stain resistance of the conventional organic solvent-based coating film, attempts have been made to incorporate an organo (alkyl) silicate into the organic solvent-based coating material, for example, WO94 / 06870. , JP-A-9
157584 and JP-A-9-137119. According to these publications,
It is described that as a result of hydrophilizing the obtained coating film surface, contaminants adhering to the coating film surface are washed away by rainfall or the like.

[0004]

Certainly, according to the method described in the above publication, it is possible to impart a certain degree of stain resistance to the coating film. However, in recent years, the structures of buildings and civil engineering structures have become increasingly complex,
It tends to be large, and cleaning with water (rainfall or the like) is often difficult. In addition, when cleaning by rain cannot be expected, as in the case of a coating applied to the inner surface of a tunnel, it is not only easy to wash with water, but also it is difficult for contaminants to adhere to the coating surface itself. Properties are also very important for coatings. Therefore, in coatings applied to the surfaces of buildings and structures, especially inner surfaces such as tunnels, ultra-low-contamination coatings having more stain resistance than before are desired. In a paint obtained by mixing an alkyl silicate with such an organic solvent-based paint, there is a limit in the stain resistance of the resulting coating film.

The present invention has been made based on such a demand, and it is an object of the present invention to provide a coating film having excellent weather resistance and other physical properties of a coating film and extremely excellent stain resistance. It is in.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that an undercoat coating layer containing a specific amount of a silanol group-containing compound or a silanol group-forming compound and a specific acrylic silicone resin It has been found that a coating having a two-layer structure composed of a water-based overcoating layer containing the same is extremely excellent in stain resistance, and has completed the present invention.

That is, the present invention provides an undercoat film layer comprising a paint (A) containing a compound having a silanol group or a compound which forms a silanol group by hydrolysis.
And a top coat layer composed of an aqueous paint (B) containing an acrylic silicone resin, wherein the content of the compound containing a silanol group or the compound that produces a silanol group by hydrolysis is the total weight of the paint (A). 1 to 5 for
0% by weight, and the acrylic silicone resin is 40 to 6%.
The present invention relates to a low-contamination coating film, which is a hybridized emulsion resin of 0% by weight of an acrylic resin and 40 to 60% by weight of a silicone resin.

[0008] The present invention also relates to the present invention, wherein the paint (A)
Is applied and dried to form an undercoating layer, and then the water-based paint (B) is applied on the undercoating layer and dried to form an overcoating layer. A method for forming the same.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION <Undercoat Coating Layer> The undercoat coating layer in the present invention is a compound containing a silanol group or a compound which forms a silanol group by hydrolysis (hereinafter, both are collectively referred to as a "silicon compound"). (May be abbreviated in some cases.). The paint (A) may be a water-based paint or an organic solvent-based paint, and may be a one-pack paint or a two-pack paint.

The "compound containing a silanol group" is not particularly limited as long as the compound contains a silanol group (-SiOH). Examples of the compound include colloidal silica and hydrophilic silica. Fine powder, hydrophobic silica fine powder, and silanol group-containing silicone compound. Among these, colloidal silica, hydrophilic silica fine powder and the like are used for water-based coatings, and hydrophobic silica fine powder is used for organic solvent-based coatings. Further, the silanol group-containing silicone compound can be used for both aqueous paints and organic solvent paints.

The "compound which forms a silanol group by hydrolysis" includes, for example, an organoalkoxysilane compound, a partially hydrolyzed condensate of an organoalkoxysilane compound, a tetrafunctional alkoxysilane compound, and a partial compound of a tetrafunctional alkoxysilane compound. Hydrolysis condensates and siloxane polymers are exemplified. When the coating material (A) is a two-pack type coating material, a polyisocyanate compound (a compound that generates a silanol group by hydrolysis) in which silicone is introduced as a curing agent into a main material, preferably a main material containing the above-described silicon compound, is used. Can also be added.

Here, the organoalkoxysilane compound can be represented by R ¹ _a- Si (OR ² ) _4-a .
Here, R ¹ is an alkyl group having 1 to 10 carbon atoms;
C1-C11 epoxyalkyl groups such as glycidoxypropyl group and 3,4-epoxycyclohexyl group; aryl groups such as phenyl group, tolyl group and xylyl group; vinyl group, allyl group and γ-acryloyloxypropyl group ,
1 to 1 carbon atoms such as γ-methacryloyloxypropyl group
An alkenyl group having 1 to 11 carbon atoms such as a benzyl group; an acryloyl group, a methacryloyl group,
1 carbon atoms such as formyl, acetyl, propionyl, etc.
1 to 4 acyl groups; 1 carbon atom such as a γ-aminopropyl group
An aminoalkyl group having 1 to 5 carbon atoms; a mercaptoalkyl group having 1 to 5 carbon atoms such as a γ-mercaptopropyl group; and a haloalkyl group having 1 to 5 carbon atoms such as a γ-chloropropyl group. R ² is an alkyl group having 1 to 10 carbon atoms; 1 carbon atom
Represents an acyl group of 1 to 4. a represents an integer of 1 to 3.

Specific examples of the alkyl group having 1 to 10 carbon atoms for R ¹ include a chain alkyl group such as a methyl group, an ethyl group, a propyl group and an n-butyl group; a cyclopentyl group and a cyclohexyl group. And a cyclic alkyl group such as a group. Among them, a methyl group, an ethyl group or an n-butyl group is preferred from the viewpoint of hydrolysis reactivity and condensation reactivity. Note that, as R ¹ , it is general to use a methyl group and an ethyl group from the viewpoint of hydrolysis reactivity and condensation reactivity.
A methyl group is preferred.

The alkyl group having 1 to 10 carbon atoms in R ² is not particularly limited, and there is no problem as long as it is exemplified in the above R ¹ . Among them, a methyl group, an ethyl group or an n-butyl group is preferred. Similarly, examples of the acyl group having 1 to 4 carbon atoms include those exemplified above for R ¹ . Among these, as R ² , a methyl group and an ethyl group are generally used in consideration of hydrolysis reactivity and condensation reactivity, and a methyl group is preferable.

Further, as for a, it is preferable that a = 1, and in such a case, the organoalkoxysilane compound becomes a trifunctional organoalkoxysilane, so that the hydrolysis reactivity and the condensation reactivity are good. . a = 1
Specific examples of the organoalkoxysilane compound in the case of are methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltrimethoxysilane. Ethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ
-Glycidoxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloxytrimethoxysilane, γ-aminopropyltrimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, vinyl tris (βmethoxyethoxy ) Silane, vinyltrisethoxysilane, vinyltrismethoxysilane, and the like. These organoalkoxysilane compounds may be used alone or in combination of two or more.

The partially hydrolyzed condensate of an organoalkoxysilane compound is obtained by partially hydrolyzing and condensing an organoalkoxysilane compound in advance. The partially hydrolyzed condensate of the organoalkoxysilane compound can be obtained by a known method, for example, by adding a predetermined amount of water and a catalyst to at least one of the above-mentioned organoalkoxysilane compounds and reacting them.

The tetrafunctional alkoxysilane compound is Si
(OR ³ ) ₄ (wherein, R ³ represents an alkyl group having 1 to 10 carbon atoms or an acyl group having 1 to 4 carbon atoms). Here, examples of the alkyl group having 1 to 10 carbon atoms for R ³ include a methyl group, an ethyl group, a propyl group, an n-butyl group and the like. Can be the same as those exemplified for R ¹ above. Specific examples of the tetrafunctional alkoxysilane compound include tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane and the like, among which tetraethoxysilane is preferable.

The partially hydrolyzed condensate of a tetrafunctional alkoxysilane compound is obtained by partially hydrolyzing and condensing a tetrafunctional alkoxysilane compound in advance. The partially hydrolyzed condensate of the tetrafunctional alkoxysilane compound is, for example, at least one of the above tetrafunctional alkoxysilane compounds.
It can be obtained by adding necessary amounts of water and a catalyst to the seed, and, if necessary, adding a solvent to remove the alcohol generated by the hydrolytic condensation reaction. Also,
After obtaining an oligomer that is a condensate of the above-mentioned tetrafunctional alkoxysilane compound, a partial hydrolysis condensate of the tetrafunctional alkoxysilane compound is also obtained by reacting the oligomer. Such a partially hydrolyzed condensate is a compound that can form silanol (SiOH) groups and silanol groups.
Contains a large amount of OR groups.

The partially hydrolyzed condensate of the above tetrafunctional alkoxysilane compound (tetraethoxysilane) includes S
Those having an iO ₂ content of 40% are preferably used. Those having a SiO ₂ content of 40% are commercially available, for example, ES-40 (manufactured by Colcoat),
Examples thereof include silicate 40 (manufactured by Tama Chemical Co., Ltd.), TES40 (manufactured by Hoechst), Sylbond 40 (manufactured by Stofffer), ethyl silicate 40 (manufactured by Union Carbide), and the like. These commercially available products are oligomers, and include a mixture of monomers, dimers, trimers, and higher molecular compounds.

The siloxane polymer in the present invention is:
R ⁴ _b -Si [(OR ⁵⁾ _3-b] -O- (wherein, R ⁴ is an alkyl group having 1 to 10 carbon atoms, an epoxy group of 1 to 11 carbon atoms, an aryl group, 1 to 4 carbon atoms Alkenyl group of 1 to 11, aralkyl group of 1 to 11 carbon atoms, acyl group of 1 to 4 carbon atoms, aminoalkyl group of 1 to 5 carbon atoms, 1 to 1 carbon atoms
5 represents a mercaptoalkyl group or a haloalkyl group having 1 to 5 carbon atoms. R ⁵ represents an alkyl group having 1 to 10 carbon atoms or an acyl group having 1 to 4 carbon atoms. b is 0
Represents an integer of 1 to 3. And R ^6-
At least one of the substituents represented by O- (wherein, R ⁶ represents an alkyl group having 1 to 10 carbon atoms or an acyl group having 1 to 4 carbon atoms) is represented by the following formula: It is bonded to a Si atom.

Here, R ⁴ is an alkyl group having 1 to 10 carbon atoms, an epoxyalkyl group having 1 to 11 carbon atoms, an aryl group, an alkenyl group having 1 to 11 carbon atoms,
1 aralkyl group, 1 to 4 carbon acyl group, 1 carbon atom
Aminoalkyl group of 1 to 5, mercaptoalkyl group of 1 to 5 carbon atoms, haloalkyl group of 1 to 5 carbon atoms,
There is no particular limitation, and examples thereof include those exemplified above for R ¹ .

The alkyl group having 1 to 10 carbon atoms and the acyl group having 1 to 4 carbon atoms in R ⁵ are not particularly limited, and there is no problem as long as they are exemplified by R ¹ described above. Further, as the alkyl group having 1 to 10 carbon atoms and the acyl group having 1 to 4 carbon atoms in R ⁶ , those exemplified for the above R ¹ can also be mentioned.

The above-mentioned siloxane polymer can be obtained by a hydrolysis-condensation reaction of an organoalkoxysilane monomer. Here, as the organoalkoxysilane monomer, for example, methyltrimethoxysilane,
Methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane,
γ-methacryloxytrimethoxysilane, γ-aminopropyltrimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane and the like can be mentioned.

The siloxane polymer obtained as described above has a Mw (polystyrene conversion value by gel permeation chromatography (GPC)) of 200.
It is preferably from 0 to 50,000, more preferably from 3,000 to 30,000. In addition, as such siloxane polymer, for example, X-40-175 (manufactured by Shin-Etsu Chemical Co., Ltd.), X-40-9740 (manufactured by Shin-Etsu Chemical Co., Ltd.), DC-3074 (Toray Dow Corning.
Silicone Co., Ltd.), DC-3037 (Toray Dow Corning Silicone Co., Ltd.), SR-2402 (Toray Dow Corning Silicone Co., Ltd.), DC-6-2
230 (manufactured by Toray Dow Corning Silicone Co., Ltd.).

The polyisocyanate compound introduced with silicone used as a curing agent in a two-pack type paint is at least one of a nurate type polyisocyanate.
An aminosilane compound is added to two isocyanate groups, for example, a compound represented by the following structural formula.

[0026]

In the present invention, it is preferable to use, as a curing agent, a polyisocyanate compound into which silicone, which is a compound that generates a silanol group by hydrolysis, is introduced. In such a case, the silicone resin is contained in the main agent. It is not necessary. However, from the viewpoint of the adhesion between the base material and the overcoat layer, the strength of the coating film, and the resistance to cracking, the polyisocyanate compound containing silicone as the effect agent and the resin component and the main component containing the silicon compound are used. It is preferable to use the organic solvent-based two-pack type paint for the undercoating layer.

In the present invention, from the viewpoint of maintaining the adhesion to the water-based topcoat paint (B), the paint (A)
The amount of the silicon compound with respect to the total weight of
It must be 50% by weight, preferably 5 to 40% by weight.

As a resin component (binder) in the coating material (A), an acrylic resin is mainly used, but an alkyd resin or a urethane resin (two-pack type) may be used, and in consideration of physical properties such as weather resistance. , A fluorine resin, a silicone resin, an acrylic silicone copolymer resin, or the like can also be used. If necessary, the resin component may include a curing agent,
A catalyst or the like may be included. When the coating material (A) is an organic solvent-based coating material, examples of the solvent component include toluene, xylene, cyclohexane, vinyl acetate, and ethyl acetate.

The undercoat film layer of the present invention can be colored. In this case, the paint (A) contains an inorganic pigment or an organic pigment. In addition, as the inorganic pigment, titanium oxide, carbon black, yellow iron oxide, red iron oxide and the like,
Examples of the organic pigment include an azo pigment, a phthalocyanine pigment, and a condensed polycyclic pigment. The content of the pigment varies depending on the color to be colored, but is generally 15 to 55% by weight.

The acid value of the resin component in the paint (A) is preferably in the range of 0 to 40 KOH mg / g (per solid), more preferably 5 to 15 KOH mg / g (per solid), and the hydroxyl value is Preferably 5-140K
OHmg / g (per solid), more preferably 20 to
Tg is in the range of 60 KOHmg / g (per solid).
Preferably it is in the range of 0 to 55 ° C, more preferably 10 to 30 ° C. When the oxidation, hydroxyl value and Tg of the resin component are within the above ranges, the cost and performance of the paint (adhesion and weather resistance)
It is preferable because it has an excellent balance with the above.

In addition, the paint (A) may be used in various applications.
In addition to the above components, a dispersant, a leveling agent, an antioxidant, an ultraviolet absorber, an anti-settling agent, a fungicide, a matting agent, and the like may be added as long as the object of the present invention is not impaired.

The method for preparing the paint (A) in the present invention is not particularly limited, and it can be prepared according to a conventionally well-known method. For example, as a method for producing an organic solvent-based two-pack paint containing a pigment, the following method may be mentioned. That is, first, an organic solvent and a dispersant are mixed with the resin component, and then, while stirring the mixture with a dissolver, a pigment is gradually added and dispersed in the mixture to prepare a dispersion base. A solvent, a resin component, and an additive are further added to and mixed with the obtained dispersion base. Finally, a silicon compound is added, and the mixture is uniformly stirred to obtain a base material. Immediately before application as a paint, a curing agent is added to the main agent to make a paint.

As a method for producing a water-based, self-crosslinking paint containing a pigment, the following method can be mentioned. First, a thickener, a dispersant, and an additive are added to water and mixed. Next, while stirring this mixture with a dissolver, the pigment is gradually added to and dispersed in the mixture to form a primary dispersion, which is further dispersed using a sand mill to produce a mill base. Water and a self-crosslinking resin component are added to and mixed with the mill base, and further, an additive and a silicon compound are added, and the mixture is sufficiently mixed and dispersed using a dissolver to obtain a paint.

The method for forming the undercoating film layer using the paint (A) is not particularly limited, and may be a conventional coating method such as brush coating or spray coating. Regarding the drying method after application, any of normal temperature drying, heat drying, and heat baking may be used.

The thickness of the undercoat layer is 10 to 100 μm.
And more preferably 30 to 6
The range is 0 μm.

<Overcoat Film Layer> The overcoat film layer in the present invention is obtained by applying an aqueous coating material (B) containing an acrylic silicone resin on the undercoat film layer. Here, the “acrylic silicone resin” in the present invention refers to 40 to 60% by weight of acrylic resin and 40 to 6% by weight.
The term “hybridization” refers to an emulsion resin in which 0% by weight of a silicone resin is hybridized, and “hybridization” means that an acrylic resin and a silicone resin intermingle (coexist) with each other in a microscopic structure, that is, an interpenetrating network structure. (IPN). Here, when the amount of the silicone resin in the acrylic silicone resin is less than 40% by weight, the adhesion to the undercoat coating layer, stain resistance, and stain washability are reduced. It becomes difficult to form a coating film. Further, the water-based coating (B) is preferably a clear coating from the viewpoint of crack resistance and gloss of the coating film.

The method for producing the acrylic silicone resin of the present invention may be in accordance with the method described in JP-A-10-183064.
The organoalkoxysilane is subjected to a hydrolysis-condensation reaction to form a silicone resin, the obtained silicone resin is dissolved in an acrylic monomer, and then a mixture containing a silicone resin-containing acrylic monomer solution is polymerized to form an acrylic silicone resin. Can be obtained.

The other components contained in the water-based paint (B) include a high-boiling solvent (film-forming aid), a defoaming agent, a thickener, and the like. From the viewpoint, it is preferable to use a high boiling point solvent (a film-forming auxiliary).

Using an aqueous silicone paint (B) containing an acrylic silicone resin and, if necessary, the above-mentioned other components,
The method for forming the top coat layer is not particularly limited, and may be a conventional coating method such as brush coating or spray coating. Regarding the drying method after application, any of normal temperature drying, heat drying, and heat baking may be used. Furthermore, the thickness of the top coat layer is 10 to 50 μm.
m.

The substrate surface to which the two-layered coating film composed of the undercoating film layer and the overcoating film layer of the present invention can be applied includes slate plate, concrete surface, siding board, mortar, brick, glass , Gypsum board, iron, metal such as aluminum sash, and plastic surface. Since the coating film of the present invention is particularly excellent in stain resistance, when applied to a concrete surface or a siding board in a building or a structure, a very excellent effect can be exhibited.

[0042]

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples and comparative examples, but the present invention is not limited to these examples.

<Coating (A) used as undercoat coating layer
Preparations of 1) to (A11)> Coatings (A1) to (A1) used for the undercoat layer based on the formulations shown in Table 1 below
1) was produced. Table 2 shows the composition of the resin components (a) to (f). Among the silicon compounds shown in Table 1, the organosilicate hydrolyzate is organosilicate 40 manufactured by Union Carbide Co., Ltd., Aerogel is R972 manufactured by Nippon Aerogel Co., Ltd., and siloxane polymer is Toray Toray. Dow Corning Silicone SR-240
2 and Snowtex 40 (Si content 40 wt%) manufactured by Nissan Chemical Industries, Ltd. were used as colloidal silica. Regarding the viscosity of the resin component, JIS K5
The viscosity was measured using a B-type rotary viscometer manufactured by Tokyo Keiki Co., Ltd. (measurement temperature: 25 ° C. ± 0.5 ° C.), and the weight average molecular weight was determined by GPC (column: HLC-8120).
(Manufactured by Tosoh Corporation), carrier: tetrahydrofuran, standard sample: polystyrene).

[0044]

[Table 1]

[0045]

[Table 2]

<Coating (B) used as a top coat layer
1) to (B3)> As the paint used for the top coat layer,
The following (B1) to (B3) were used. B1: Acrylic silicone (IPN) emulsion (amount of silicone resin: 50% by weight) B2: Acrylic emulsion (amount of silicone resin: 0)
B3: acrylic silicone emulsion (amount of silicone resin: 10% by weight)

<Preparation of Two-Layer Coating Film> [Example 1] 4 mm × 150 mm × 30 whose surface was cleaned
On a slate plate having a thickness of 0 mm, a paint A1 for an undercoat coating layer was spray-coated. The coating amount is 0.15 to 0.2 kg / m
² , after coating, dried for 24 hours at room temperature, about 50μ thickness
m was obtained. Next, a paint B1 for a top coat layer diluted with about 5% of water was applied on the undercoat layer.
Spray coating was performed so that the coating amount was 0.1 to 0.15 kg / m ² . After painting, dry at room temperature for 24 hours,
It was dried at 00 ° C. for 10 minutes to obtain a glossy topcoat layer having a thickness of 30 to 50 μm. Thus, a two-layer coating film consisting of the undercoating film layer and the overcoating film layer was obtained. The physical properties of the obtained coating film were evaluated as follows, and the evaluation results are summarized in Table 3.

Examples 2 to 9 and Comparative Examples 1 to 4 The undercoating was carried out in the same manner as in Example 1 except that the coatings shown in Table 3 were used as the undercoating layer and the overcoating layer. A two-layer coating film consisting of a film layer and a top coating layer was obtained. The physical properties of the obtained coating film were evaluated in the same manner as in Example 1, and the evaluation results are summarized in Table 3.

<Evaluation Method of Coating Physical Properties> (Adhesion) The adhesion between the undercoating layer / substrate and the overcoating layer / undercoating layer in each coating film was evaluated by a basic test (JIS K540008). Adhesion was evaluated by a cross-cut test method of 2.5). Specifically, after forming an undercoat or topcoat film, the test plate was allowed to stand at 20 ° C. and 65% for 2 weeks to form a test plate, and a checkerboard (25) was formed on the test plate using a cutter guide with a gap of 2 mm. Grids;
(5 vertical divisions x 5 horizontal divisions) were made. Next, a cellophane tape was adhered so as to cover the entire 25 grids, and one end of the adhered cellophane tape was held and immediately peeled off in a direction perpendicular to the coating surface. The case where the coating film does not come off at all 2
In the case where peeling occurred, the adhesion was indicated by “25− (number of peeled grids)”.

(Initial Gloss (60 °)) The 60 ° gloss of the coating film surface immediately after the formation of the overcoat film layer was measured using a gloss meter manufactured by Nippon Denshoku Industries.

(Weather Resistance) [Accelerated Deterioration Test] An accelerated degradation test of a coating film formed on a slate plate was performed using a sunshine weather meter (SWOM) in accordance with JIS K5400. .
After 4000 hours of irradiation time, the gloss value of the coating film (60
°) was measured using a gloss meter of Nippon Denshoku Industries Co., Ltd. It can be said that the closer the gloss value of the coating film after 4000 hours to the value of the initial gloss, the better the weather resistance.

[Outdoor Exposure Test] A coating film specimen having a coating film formed on a slate plate was fixed on a weathering test table inclined at a south surface of 30 °, and the gloss of the coating film surface was observed for one year.
The test specimens were installed in places where there were no ground-based properties that would prevent direct sunlight, ventilation, and precipitation, and where there were few environmental pollutants such as toxic gases and vapors. One year after this outdoor exposure, the 60 ° gloss of the test specimen was measured using a gloss meter (Nippon Denshoku Industries Co., Ltd.). The 60 ° gloss measurement was performed after removing dust on the surface of the test specimen. It can be said that the closer the gloss value of the coating film after one year of outdoor exposure to the value of the initial gloss, the better the weather resistance. In Comparative Examples 3 and 4, the gloss value could not be measured because cracks occurred on the surface of the test piece during outdoor exposure.

(Contamination) [Outdoor exposure test] A coating film specimen having a coating film formed on a slate plate was fixed on a weather test table inclined at 30 ° to the south side.
For one year, the coating film was observed for contamination. The test specimen has no ground-based properties that hinder direct sunlight, ventilation, and precipitation.
In addition, it was installed in a place where there are few environmental pollutants such as toxic gas and steam. The whiteness of the test specimen one year after the outdoor exposure was measured before and after the cleaning (in running water, removing dust on the coating surface with a brush) using a color difference meter (Nippon Denshoku Industries Co., Ltd.). And the difference ΔL * from the initial whiteness of the test specimen. The larger the negative value of ΔL *, the darker the coating film appears, indicating that the coating is more contaminated. In Comparative Examples 3 and 4, the degree of whiteness could not be measured because the test piece cracked during outdoor exposure.

(Crack resistance) [Repeated test of heating and cooling] The test was repeated in accordance with the JIS K5400 9.4 resistance test of wet and cold heat resistance. Specifically, a coating film specimen having a coating film formed on a slate plate was immersed in water at 20 ° C. for 18 hours, and then heated in a −20 ° C. freezer for 3 hours and further at 50 ° C. for 3 hours. This cycle was repeated 10 cycles, and the state of the coating film was visually observed. Cracks in the coating,
If no peeling, swelling, or whitening is observed, there is no abnormality
And In addition, about the test body of Example 1, a test was performed continuously also after 10 cycles, and the fine crack was observed on the coating film surface for the first time after 32 cycles.

[0055]

[Table 3]

Comparative Example 5 A coating film consisting of only an undercoat coating layer was obtained in the same manner as in Example 1 except that no overcoat coating layer was provided. The physical properties of the obtained coating film were evaluated in the same manner as in Example 1, and the evaluation results are summarized in Table 6.

Comparative Example 6 4 × 150 × Surface Cleaned
Fluorine paint was spray-coated on a 300 mm slate plate. The coating amount was 0.15 to 0.2 kg / m ² , and the coating was dried at room temperature for 24 hours to obtain a coating layer having a thickness of about 50 μm. In addition, the composition of the fluorine paint used here is as shown in Table 4 below. In addition, the viscosity of the fluorine paint
2000 (mPa · s, 25 ° C), solid content 66wt
% And density were 1.34. The physical properties of the obtained coating film were evaluated in the same manner as in Example 1, and the evaluation results are summarized in Table 6.

[0058]

[Table 4]

Comparative Example 7 4 × 150 × Surface Cleaned
A urethane paint was spray-coated on a 300 mm slate plate. The application amount is 0.15 to 0.2 kg / m ² ,
After coating, the coating was dried at room temperature for 24 hours to obtain a coating layer having a thickness of about 50 μm. The composition of the urethane paint used here was
As shown in Table 5 below. The urethane paint had a viscosity of 2600 (mPa · s, 25 ° C.), a solid content of 62 wt%, and a density of 1.18. The physical properties of the obtained coating film were evaluated in the same manner as in Example 1, and the evaluation results are summarized in Table 6.

[0060]

[Table 5]

[Comparative Example 8] 4 mm x 15 with clean surface
On a 0 mm x 300 mm slate plate, 50 wt% B
A paint consisting of 1,22% by weight of titanium oxide, 8% by weight of additives and 20% by weight of water was spray painted. The coating amount is 0.15 to 0.2 kg / m ^2, and 2
After drying for 4 hours, a coating layer having a thickness of about 50 μm was obtained. The physical properties of the obtained coating film were evaluated in the same manner as in Example 1, and the evaluation results are summarized in Table 6.

Reference Example 1 A coating film consisting of only the top coating film layer was obtained in the same manner as in Example 1 except that the undercoat coating layer was not provided. The physical properties of the obtained coating film were evaluated in the same manner as in Example 1, and the evaluation results are summarized in Table 6.

[0063]

[Table 6]

As is clear from the results of Tables 3 and 6, in Comparative Example 1 in which the acrylic emulsion (B2) containing no silicone resin was used as the overcoat layer, the adhesion between the undercoat layer and the overcoat layer was determined. However, the coating film is not sufficiently satisfactory, and the weather resistance and stain resistance of the coating film are very poor as compared with the results of Example 1. Further, Comparative Example 2 using acrylic silicone emulsion (B3) containing 10% by weight of a silicone resin as a top coat layer was the same as Comparative Example 1.
It was confirmed that the adhesion between the undercoat film layer and the overcoat film layer and the stain resistance of the paint film were not sufficient, and that there was also a problem in the crack resistance of the paint film.

On the other hand, in Comparative Examples 3 and 4 in which the paints (A10) and (A11) in which the amount of the silicon compound was out of the range of the present invention were used as the undercoat layer, the base material, the undercoat layer, and the undercoat layer were used. The adhesion between the coating layer and the top coat layer is very poor, and in the outdoor exposure test, the coating film cracks during the test, and the weather resistance and stain resistance test cannot be performed. Was. Furthermore, even in the test of repeated heating and cooling of the coating film, the coating film cracked at an early stage, and the crack resistance of the coating film was not sufficient.

Next, in the coating film of Comparative Example 5 consisting of only the undercoating film of the present invention, even if the undercoating film layer is included in the range of the present invention, the gloss of the coating film and It was found that all of the weather resistance, stain resistance and crack resistance were inferior to the physical properties of the two-layer coating film of the present invention.
Further, it was confirmed that even the coating films of Comparative Examples 6 and 7 in which only the coating material containing no silicon compound was applied could not obtain excellent physical properties, and in particular, the stain resistance was very poor.

Further, the coating film of Comparative Example 8 obtained by applying only the coating material obtained by adding a pigment or the like to the coating material (B1) used for the top coating film layer of the present invention also has a two-layer structure of the present invention. As a result, the weather resistance, the stain resistance, and the crack resistance were inferior to those of the coating film No. 1. In particular, it was found that the crack resistance was significantly inferior to the paint of the present invention. For reference, the physical properties of the coating film provided with only the top coating film layer of the present invention were evaluated (Reference Example 1), and the adhesion, gloss, weather resistance, and stain resistance of the coating film of the present invention were evaluated. Has the same physical properties as the membrane,
With respect to the crack resistance, the results showed that the coating film of the present invention was superior. In the coating film of the present invention, both the undercoat film layer and the topcoat film layer have a high proportion of Si.
It is presumed that the interaction based on hydrogen bond, chemical bond and the like is large between the two coating layers, and that the coating film on the slate plate is hard to crack.

[0068]

As described above, according to the present invention, it is possible to obtain a coating film having significantly improved stain resistance as compared with a conventional coating film. Further, the coating film of the present invention is excellent in adhesion to a substrate, gloss, weather resistance, crack resistance, and the like, and can be colored, so that it can be applied to various uses. Can be.

Further, in recent years, from the viewpoint of securing the safety of the global environment and working environment, it has been required to change the conventional organic solvent-based paint to a water-based paint. Since it is a water-based paint, it is very excellent in terms of environmental issues and safety for workers.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C09D 5/16 C09D 5/16 143/04 143/04 183/04 183/04 201/10 201/10 ( 72) Inventor Kazuyoshi Nomura 1-11-12, Mutsumicho, Kazo City, Saitama F-term (reference) EB43 EB45 EB56 EC03 4F100 AA20H AK25B AK51 AK52B AL05A AT00C BA02 BA03 BA07 BA10B BA10C CC00A CC00B EH46 EH462 EJ86 EJ862 GB07 JL06 JM01A JM02A YY00A 4J038 AA03 003 001 CG001 CG001 001 PC08

Claims (2)

[Claims] 1. An undercoating film layer comprising a paint (A) containing a compound containing a silanol group or a compound generating a silanol group by hydrolysis, and an overcoat consisting of an aqueous paint (B) containing an acrylic silicone resin. A low-contamination coating film comprising a coating film layer, wherein the content of the compound containing a silanol group or the compound that generates a silanol group by hydrolysis is 1 to the total weight of the coating material (A).
-50% by weight, and the acrylic silicone resin is 40% by weight.
The above low-contamination coating film, which is a hybridized emulsion resin of -60% by weight of an acrylic resin and 40-60% by weight of a silicone resin. 2. After coating the coating material (A) on a substrate and drying to form an undercoat film layer, the aqueous coating material (B) is coated on the undercoat film layer and dried to form a topcoat film. The method for forming a low-contamination coating film according to claim 1, comprising forming a layer.