JP2003033723A - Film and method for painting film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film where antifouling property is better maintained when a constitution is provided with a primer layer and its painting method. SOLUTION: In the method for painting the film having a process, wherein after a primer paint containing an organic thermosetting resin is painted on the surface of a substrate to be painted, the primer layer is formed by drying the substrate, after a silicon resin paint is further painted on the surface of the substrate and a surface layer is formed by again drying the substrate, the method for painting the film where the silicon resin paint is arranged so as to contain the curing catalyst of the organic thermosetting resin and the film painted by its painting method.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating film obtained by forming a primer layer on the surface of a substrate to be coated and further forming a surface layer on the surface with a silicone resin coating, and a coating method for the coating film. It is about.

[0002]

2. Description of the Related Art In order to impart an antifouling property to the surface of a substrate such as a plastic substrate to be coated, a silicone resin paint is applied to the surface of the substrate to form a hydrophilic coating film. . By making the surface of the base material hydrophilic with a hydrophilic coating film, it becomes possible to wash away stains adhering to the surface naturally with rainwater or the like, and impart antifouling property to the base material.

Further, as seen in JP-A-10-76600, etc., a layer of an organic curable resin is formed of a base material and a silicone resin coating (hereinafter referred to as a surface layer) in order to further improve performance. (Note) is formed as a primer layer in the middle. As the performance to improve,
For example, functions such as ultraviolet resistance, weather resistance, or improvement of adhesion can be mentioned.

However, when the above-mentioned primer layer is provided, the hydrophilic property of the surface layer formed of the silicone resin coating may be deteriorated, and the antifouling property of the coating film may be deteriorated accordingly.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a coating film and a coating method thereof in which good antifouling property is maintained when a primer layer is provided. The challenge is to provide.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the inventors of the present invention have found that a curing catalyst for an organic curable resin used for forming a primer layer is used as a surface layer. The present invention has been completed by finding that the above problems can be solved by adding it to the silicone resin coating used for forming it in advance.

In the present invention, a primer coating is applied to the surface of a base material and then dried to form a primer layer, from the silicone resin coating applied to the surface, to the organic cured resin previously added to the silicone resin coating. The curing catalyst diffuses and further hardens the organic curable resin at the interface between the surface layer and the primer layer, and the hardened organic curable resin serves as a barrier to prevent uncured resin in the primer layer. It is considered to prevent the organic component from diffusing into the surface layer.

The coating method of the coating film of the invention according to claim 1 is
After applying a primer coating containing an organic curable resin to the surface of the substrate to be coated, it is dried to form a primer layer, and then a silicone resin coating is applied to the surface and then dried again to form a surface layer. In the method for coating a coating film, the method comprises the step of forming a coating composition, wherein the silicone resin coating material contains a curing catalyst for the organic curable resin.

The coating method of the invention according to claim 2 is
The coating method for a coating film according to claim 1, wherein the silicone resin coating material is a tetrafunctional alkoxy represented by the general formula Si (OR) ₄ (wherein R represents the same or different monovalent hydrocarbon group). It is characterized by containing a hydrolyzate of silane.

The coating method of the coating film of the invention according to claim 3 is
In the coating method of the coating film according to claim 1 or 2,
The above-mentioned organic curable resin is an organic curable resin containing a compound having an isocyanate group.

The coating method of the coating film of the invention according to claim 4 is
The coating method according to any one of claims 1 to 3, wherein the curing catalyst for the organic curable resin is an amine-based or tin-based curing catalyst.

The method for coating a coating film of the invention according to claim 5 is
The coating method according to claim 4, wherein the amine-based curing catalyst is γ-aminopropyltrimethoxysilane.

The coating film of the invention according to claim 6 is characterized in that it is coated by the coating method according to any one of claims 1 to 5.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION First, an embodiment of a coating film coating method according to the present invention will be described.

In the present invention, the organic curable resin contained in the primer coating used for forming the primer layer is not particularly limited, but for example,
Urethane-acrylic resin, urethane resin, alkyd resin, which contains a compound having an isocyanate group as a crosslinking agent,
Examples thereof include polyester resins, epoxy resins, phenol resins and melamine resins. Among them, those containing a compound having an isocyanate group such as urethane-acrylic resin, urethane resin, and urethane-modified alkyd resin are preferable because the effect of the curing catalyst can be further exhibited.
The urethane-acrylic resin as used herein refers to a curable resin containing a compound having an isocyanate group such as an aliphatic polyisocyanate and an acrylic resin.

In the present invention, as the curing catalyst which functions to further cure the organic curable resin of the primer layer,
Examples include amine-based or tin-based catalysts.

Specific examples of the amine-based curing catalyst include, for example, triethylenediamine, triethylamine, N-
Methylmorpholine, N, N-dimethylbenzylamine,
N, N-dimethyl laurylamine, N, ^{N-dimethylpiperazine, N, N, N ',} N' - ^{tetramethylethylenediamine, N, N, N ',} N' - tetramethyl-1,3-butanediamine, N , N, N ^' , N ^" , N ^" -pentamethyldiethylenetriamine, N, N, N ^' , N ^" , N ^" , N
^''' -Hexamethyltriethylenetetramine, hexamethylenetetramine, dibutylamine-2-hexoate, dimethylamine acetate, ethanolamine acetate and other amine salts, tetramethylammonium acetate and other carboxylic acid quaternary ammonium salts, tetraethylpentamine, γ -Aminopropyltrimethoxysilane, N-
Examples include β-aminoethyl-γ-aminopropyltrimethoxysilane and N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane.

Specific examples of the tin-based curing catalyst include metal salts of carboxylic acids such as stannous chloride, stannic chloride, tin dilaurate octylate, tin dilaurate dibutylate, and dimalyl dioctylate. .

Specific examples of other curing catalysts include naphthensancobalt, benzyltrimethylammonium hydroxide, tetra-n-tiltin, tri-n-tiltin acetate, n-butyltin trichloride, trimethyltin hydroxide, and the like.
Dimethyltin dichloride, dibutyltin trichloride, dibutyltin dilaurate, alkyl titanate,
Examples thereof include acids such as p-toluenesulfonic acid, phthalic acid and hydrochloric acid, and aluminum compounds such as aluminum alkoxide and aluminum chelate.

The amount of the above-mentioned curing catalyst added to the silicone resin coating material is not particularly limited, but is 0.001 when the total solid content in the silicone resin coating material for the surface layer is 100% by mass. It is preferably from 10 to 10% by mass, more preferably from 0.05 to 5% by mass, and most preferably from 0.1 to 2% by mass. If it is less than 0.001% by mass, the curability at room temperature tends to be poor, and 1
If it exceeds 0% by mass, heat resistance and weather resistance tend to be impaired.

The silicone resin coating material forming the surface layer in the present invention is not particularly limited, and examples thereof include a silicone resin coating material containing a hydrolyzate of a decomposable organosilane such as alkoxysilane or chlorosilane as a constituent material.

As the above-mentioned alkoxysilane, there is a 1- to 4-functional alkoxysilane, which has a general formula Si (OR) ₄ (wherein R is the same or different monovalent hydrocarbon as compared with the 1- to 3-functional alkoxysilane. A silicone resin coating material containing a hydrolyzate of a tetrafunctional alkoxysilane represented by (showing a group) is preferable because the obtained coating film has better antifouling property, surface hardness and abrasion resistance.

The form of the hydrolyzate of the above-mentioned tetrafunctional alkoxysilane is not particularly limited, and may be, for example, a solution form or a dispersion liquid form. It should be noted that the hydrolyzate referred to herein also includes a partial hydrolyzate.

R in the above general formula represents the same or different monovalent hydrocarbon group, and among them, from the viewpoints of easy availability, easy adjustment of the coating, etc., 1 having 1 to 8 carbon atoms is used. A valent hydrocarbon group is suitable. Examples of the monovalent hydrocarbon group include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, peptyl group and octyl group. Among the above alkyl groups, those having 3 or more carbon atoms may be linear ones such as n-propyl group, n-butyl group, etc., or areopyropyr group, isobutyl group, t-butyl group. It may have a branch such as a group.

The amount of water required to hydrolyze the above tetrafunctional alkoxysilane is not particularly limited. The catalyst used as necessary when hydrolyzing the tetrafunctional alkoxysilane is not particularly limited, but an acidic catalyst is preferable from the viewpoint of shortening the time involved in the production process. The acidic catalyst is not particularly limited,
For example, acetic acid, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid, toluenesulfonic acid, organic acids such as oxalic acid, hydrochloric acid, nitric acid, halogen. Examples thereof include inorganic acids such as silane silane, acidic colloidal silica, and acidic sol fillers such as titanium oxide sol. These can be used alone or in combination.

Hydrolysis of the tetrafunctional alkoxysilane may be carried out, if necessary, by heating at about 40 to 100 ° C. Further, if necessary, it may be diluted with an appropriate solvent. Such a diluting solvent is not particularly limited, but for example, lower fatty acid alcohols such as methanol, ethanol, isopropanol, n-butanol, isobutanol, ethylene glycol,
Ethylene glycol monobutyl ether, ethylene glycol derivatives such as ethylene glycol monoethyl ether acetate, diethylene glycol, diethylene glycol derivatives such as diethylene glycol monobutyl ether,
And diacetone alcohol and the like, and one or more selected from these can be used. Furthermore, one or more of toluene, xylene, hexane, ethyl heptane acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime, etc. can be used in combination with these hydrophilic organic solvents. .

The weight average molecular weight of the hydrolyzate of the above-mentioned tetrafunctional alkoxysilane is not particularly limited, but is 5
The range of 00 to 30,000 is preferable. If it is less than 500, the hydrolyzate tends to be unstable or the hydrophilicity tends to decrease, and if it exceeds 30,000, the hardness of the formed coating film tends to be insufficient. .

In the present invention, it is important to add a curing catalyst that functions to cure the organic curable resin forming the primer layer to the silicone resin coating forming the surface layer. Also, it does not prevent the addition of the curing catalyst. In this case, it is desirable that the amount of the curing catalyst added to the primer coating is an amount of curing catalyst that does not make the primer coating unstable. If the primer coating becomes unstable, the pot life of the primer coating cannot be sufficiently secured, the leveling at the time of coating becomes poor, and as a result, the transparency of the coating film deteriorates and alkali resistance test This is because adverse effects such as film peeling are likely to occur.

The method for applying the primer coating and the silicone resin coating is not particularly limited, and examples thereof include brush coating, spray coating, dipping (dip coating), roll coating, flow coating, curtain coating, knife coating and spin coating. A usual method such as coating or bar coating can be appropriately selected. The drying temperature is also not particularly limited, but it can be handled in the temperature range from room temperature to 500 ° C in consideration of the heat resistant temperature of the substrate used.

The thickness of the primer layer of the present invention is not particularly limited, but is preferably about 0.1 to 50 μm, because the primer layer is stably adhered and held for a long period of time, and cracks and peeling do not occur. Is more preferably 5 to 20 μm. Further, the thickness of the surface layer not including the primer layer of the present invention is not particularly limited, but may be about 0.05 to 10 μm, and the coating film can be stably adhered and held for a long period of time, and can be cracked. In order not to cause peeling or peeling, 0.05 to 2 μm is preferable, and
1 to 1 μm is more preferable.

The base material to be coated used in the present invention may be inorganic or organic, and various base materials may be used. For example, an inorganic base material, an organic base material, or any of these base materials may be used. An organic coating substrate having an organic film on the surface of is mentioned.

The inorganic base material is not particularly limited, and examples thereof include a metal base material, a glass base material, an enamel base material, a water glass decorative board, an inorganic hardened inorganic building material, and ceramics. The metal substrate is not particularly limited, and examples thereof include non-ferrous metals [eg, aluminum (JIS-H4000 etc.), aluminum alloys (duralumin etc.), copper, zinc etc.], iron, steel [eg,
Rolled steel (JIS-G3101 etc.), hot-dip galvanized steel (JIS-G3302 etc.), (rolled) stainless steel (J
IS-G4304, G4305, etc.], tinplate (JI
S-G3303), other metals in general (including alloys)
Is mentioned. The glass substrate is not particularly limited, but examples thereof include sodium soda glass, heat-resistant glass, and quartz glass. As a enamel base material, bake a glassy enamel on the metal surface,
It is a film. Examples of the base metal include, but are not limited to, mild steel plate, steel plate, cast iron, aluminum and the like. The enamel is not particularly limited as long as it is a normal one. Examples of the water glass decorative plate include a decorative plate obtained by applying sodium silicate to a cement base material such as slate and baking it. The inorganic hardened body is not particularly limited, but for example, fiber reinforced cement board (JIS-A5430 etc.), ceramic-based sideling (JIS-A5422 etc.), wood wool cement board (J
IS-A5404, etc.), pulp cement board (JIS-A
5414), slate / wood wool cement laminate (JIS
-A5426), gypsum board products (JIS-A690
1), clay roof tiles (JIS-A5208 etc.), thick slate (JIS-A5402 etc.), ceramic tiles (JIS
-A5209 etc.), concrete blocks for construction (JI
S-A5406 etc.), Terrazo (JIS-A5411)
Etc.), prestressed concrete double T slab (J
IS-A5412 etc.), ALC panel (JIS-A54
16), hollow prestressed concrete panel (J
IS-A6511), standard building roof tile (JIS-R1250)
Etc.) refers to all substrates that are formed by curing and molding an inorganic material. The ceramic substrate is not particularly limited, but examples thereof include alumina, zirconia, silicon carbide, silicon nitride and the like.

The organic base material is not particularly limited, and examples thereof include a plastic base material, wood, paper and the like. The plastic substrate is not particularly limited, but examples thereof include thermosetting or thermoplastic plastics such as polycarbonate resin, acrylic resin, ABS resin, vinyl chloride resin, epoxy resin and phenol resin, and these plastics made of glass fiber, nylon. Fiber reinforced plastic (FRP) reinforced with fibers such as fiber and carbon fiber
Etc.

In the present invention, the curing catalyst for the organic curable resin in the silicone resin coating applied on the surface diffuses into the primer layer, and the organic curable resin is further hardened at the interface between the surface layer and the primer layer. Thus, it is considered that the strongly cured organic curable resin serves as a barrier to prevent the organic components such as the uncured resin in the primer layer from diffusing into the surface layer. As a result, the hydrophilicity of the surface layer formed of the silicone resin coating material is maintained, so that the antifouling property of the coating film is considered to be excellently maintained.

Next, an embodiment of the coating film according to the present invention will be described.

The coating film according to the present invention is a coating film formed by applying the coating method described in detail above. Therefore, when the coating film is provided with a primer layer, good antifouling property is obtained. A retained coating can be obtained.

[0037]

EXAMPLES Next, specific examples will be shown and described in more detail. In the following, the silicone resin paint for spraying of each example was prepared, and after forming the primer layer of each example, the surface was coated with the silicone resin paint for spraying of each example by spray coating. A film was formed and its performance was evaluated.

Example 1 Tetraethoxysilane 208
Add 356 parts by mass of isopropyl alcohol to parts by mass,
Further, 180 parts by mass of water and 18 parts by mass of 0.01N hydrochloric acid were mixed and stirred with a disper. Silica sol (trade name “ST manufactured by Nissan Chemical Industries, Ltd.”
-OL ": particle size 40 to 50 nm) was added so as to be 40 parts by mass in terms of solid content, and the mixture was heated in a constant temperature bath at 60 ° C for 6 hours. Next, 0.5 part by mass of γ-aminopropyltrimethoxysilane, which is a curing catalyst, was added, and 50,000 parts by mass of a mixed solvent of methanol / diacetone alcohol = 9/1 (mass ratio) was further added to dilute it. , A silicone resin paint for spraying was prepared.

Next, on the surface of the polycarbonate plate, a special acrylic paint containing an acrylic resin, which absorbs ultraviolet rays [trade name: "UDABLE UV-G30" manufactured by Nippon Shokubai Co., Ltd.].
0 "] 4 parts by mass of 100 parts by mass of aliphatic polyisocyanate [Sumijour N3200" manufactured by Sumitomo Bayer Urethane Co., Ltd.], which is a compound having an isocyanate group, is used as a primer, and the urethane-acrylic resin is a primer. Barcoat No. as paint It was painted at 20 and dried at room temperature for 1 day to form a primer layer.

Thereafter, the above silicone resin coating for spraying was applied to the surface of the above primer layer by spray coating and further dried at room temperature for 1 day to form a surface layer to obtain a coating film.

(Example 2) In Example 1, except that the addition amount of the curing catalyst was 1.0 part by mass,
A coating film was obtained in the same manner as in Example 1.

Example 3 A coating film was obtained in the same manner as in Example 1 except that tin dilaurate octylate was added as a curing catalyst in place of γ-aminopropyltrimethoxysilane.

(Example 4) In Example 1, dimethylamine acetate was used in place of γ-aminopropyltrimethoxysilane as a curing catalyst, and the addition amount was 1.0.
A coating film was obtained in the same manner as in Example 1 except that the amount was adjusted to be parts by mass.

Example 5 In Example 1, the curing conditions of the primer layer were 90 ° C. instead of drying at room temperature for 1 day.
A coating film was obtained in the same manner as in Example 1 except that the coating film was dried for 30 minutes.

Comparative Example 1 Coating was carried out in the same manner as in Example 1 except that the silicone resin paint for spraying prepared without adding the curing catalyst γ-aminopropyltrimethoxysilane was coated. A film was obtained.

(Comparative Example 2) In Example 1, 0.5% of γ-aminopropyltrimethoxysilane as a curing catalyst was used.
Using a primer coating prepared by adding parts by mass, and
A coating film was obtained in the same manner as in Example 1 except that the silicone resin paint for spraying prepared without adding the curing catalyst was used.

(Evaluation of Performance of Coating Film) The performance of the obtained coating film was evaluated by haze as transparency, contact angle of water as antifouling property, and
The alkali resistance was evaluated by the presence or absence of a coating film after the alkali immersion test.

(Evaluation of haze value measurement) Transparency is JIS-
Based on K-7136, the haze, which is a specific optical property for wide-angle scattering of light rays, was determined. Value 0 is transparent,
The larger the value, the higher the whiteness. The coating film having a value of 5 or less was judged to have transparency.

(Contact angle of water at the initial stage of coating film) The contact angle with water was measured by using CA-W150 manufactured by Kyowa Interface Science Co., Ltd., in which 0.2 cc of distilled water was dropped on the surface of the film. The angle was measured. It was judged that the coating film having a value of 35 or less has hydrophilicity and good antifouling property.

(Alkali resistance test) First, the film-formed sample was left to stand for 4 hours in an alkaline test solution prepared by diluting Na ₂ CO ₃ with ion-exchanged water so that the concentration thereof was 1 wt% in the ion-exchanged water. After that, the membrane was washed with ion-exchanged water and left to dry in air for 30 minutes.

[0051]

[Table 1]

(Results) Table 1 shows film forming conditions and evaluation results. In each of Examples 1 to 5, the contact angle of water was 35 degrees or less, which showed high hydrophilicity, and good antifouling property was confirmed. In addition, in all cases, the leveling at the time of application of the primer coating was good, and as a result, the haze value was low and the transparency could be maintained. Further, neither film peeling was observed in the alkali resistance test.

On the other hand, in Comparative Example 1 in which the curing catalyst was not added to the silicone resin coating, the contact angle of water was as large as 45 degrees, the hydrophilicity of the surface layer was lowered, and the antifouling property was deteriorated. It was confirmed. Further, Comparative Example 2 in which the curing catalyst was added to the primer coating material without adding the curing catalyst to the silicone resin coating material showed a high hydrophilicity with a contact angle of water of 25 degrees, and good antifouling property was confirmed. However, the leveling at the time of application of the primer coating was poor, resulting in a high haze value, poor transparency, and film peeling in the alkali resistance test.

[0054]

EFFECTS OF THE INVENTION In the coating film coating method of the invention according to claims 1 to 5, a primer coating containing an organic curable resin is applied to the surface of a substrate to be coated and then dried to form a primer layer. Further, in the coating method of a coating film, which further comprises a step of applying a silicone resin coating on the surface and then drying it to form a surface layer, the silicone resin coating contains a curing catalyst for the organic curable resin. Therefore, according to the coating film coating method of the present invention according to claims 1 to 5, it is possible to obtain a coating film in which the antifouling property is favorably held when the primer layer is provided. it can.

Since the coating film of the invention according to claim 6 is formed by the above method, the coating film having a good antifouling property can be obtained when the primer layer is provided.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 183/02 C09D 183/02 183/04 183/04 201/02 201/02 (72) Inventor Keishi Shibata Osaka Prefecture Kadoma Oaza Kadoma 1048 address Matsushita Electric Works Co., Ltd. in the F-term (reference) 4D075 AE03 AE16 BB24Y CA34 DA06 DB01 DB11 DB18 DB21 DB31 DB63 DC02 DC31 EA05 EA41 EB38 EB42 EB45 EC01 EC07 EC37 4J038 DA031 DA161 DB001 DD001 DD121 DD231 DG001 DL031 GA11 JB01 JB04 JB05 JB07 JB08 JB33 JB39 JC35 KA04 NA05 PA12 PC08

Claims (6)

[Claims] 1. A primer coating containing an organic curable resin is applied to the surface of a base material to be coated and then dried to form a primer layer, and a silicone resin coating is applied to the surface, and then again. A coating film coating method comprising a step of drying to form a surface layer, wherein the silicone resin coating material contains a curing catalyst for the organic curable resin. 2. The silicone resin paint is of the general formula Si
The coating of a coating film according to claim 1, comprising a hydrolyzate of a tetrafunctional alkoxysilane represented by (OR) ₄ (wherein R represents the same or different monovalent hydrocarbon group). Method. 3. The method for coating a coating film according to claim 1 or 2, wherein the organic curable resin contains a compound having an isocyanate group. 4. The coating method according to claim 1, wherein the curing catalyst for the organic curable resin is an amine-based or tin-based curing catalyst. 5. The method of coating a coating film according to claim 4, wherein the amine-based curing catalyst is γ-aminopropyltrimethoxysilane. 6. A coating film, which is coated by the coating film coating method according to any one of claims 1 to 5.