JP2000025156A - Protective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective film capable of easily imparting self-cleaning properties by bonding the protective film to a member to keep them over a long period of time. SOLUTION: A siliceous ceramics layer 2 comprising polysilazane or a modified matter thereof is formed on a base material 1 and a photocatalyst- containing layer 3 is formed on the outer surface of the ceramics layer 2. By bonding this protective film to a member, even if dust is bonded to the surface of the protective film or a pollutant of exhaust gas of a vehicle is bonded thereto since the surface of the protective film is made hydrophilic by the photocatalyst of the photocatalyst-containing layer 3, the pollutant is effectively washed. Since the protective film is used only by bonding the film to a member, this film can impart self-cleaning properties extremely easily even after it is bonded to the member and can also protect the member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the interior and exterior of road works or buildings, such as bridges installed outdoors, protective fences, railing, lighting, sound barriers, road signs, and gaze guidance devices. The present invention relates to a protective film that can be adhered to any member used in the above-mentioned method and can impart self-cleaning properties.

[0002]

2. Description of the Related Art For example, soundproof walls, road signs, and road works such as gaze guidance devices which are installed outdoors are constantly exposed to vehicle exhaust gas and dust, and therefore must be cleaned occasionally. There is a problem that exhaust gas, dust, and the like adhere to the surface and become dirty, which significantly lowers its function and beauty. However, since cleaning by hand is very troublesome and troublesome, a photocatalyst-containing layer containing a photocatalyst such as titanium dioxide is formed on the surface of a member such as a workpiece, and the surface is hydrophilized by the photocatalyst to perform self-cleaning. It has been proposed to impart properties.

That is, a photocatalyst such as titanium dioxide is activated by irradiating ultraviolet rays, and its surface exhibits strong oxidizing power and is highly hydrophilized, and contaminants such as dust and vehicle exhaust gas are exposed to the surface. Even if it adheres to the surface, it decomposes the contaminants, and due to the hydrophilic surface, water breaks in between the contaminants adhering to the surface and the surface to float the contaminants. Is easily washed off and removed by rainfall or the like, and contaminants are not easily deposited.

[0004]

However, in order to form such a photocatalyst-containing layer on the surface of a member such as a workpiece and maintain it for a long period of time, an intermediate layer is provided between the member and the photocatalyst-containing layer. It is necessary to improve the adhesion by doing
When the member is an organic material such as plastics, it is necessary to form an inorganic protective layer such as silicone between the member and the photocatalyst containing layer in order to protect the member from the decomposition action of the photocatalyst. In addition, it is difficult to form these photocatalyst-containing layers, intermediate layers, or protective layers after being installed outdoors or the like, and it is necessary to form them in advance in a factory or the like. Since the steps of forming the photocatalyst-containing layer, the intermediate layer, and the protective layer are added, it is very troublesome.

Conventionally, such an intermediate layer or a protective layer is generally formed by polymerizing a hydrolyzate of an alkoxysilane by a sol-gel method. However, in this sol-gel method, it is difficult to form a dense film and it is difficult to form a porous film. However, it is not enough to protect the member from the decomposition action of the photocatalyst, and sufficient heat resistance, bending resistance, abrasion resistance and the like have not been obtained.

Accordingly, the present invention solves the above-mentioned problems,
It is an object of the present invention to provide a protective film that can easily impart self-cleaning property by sticking to a member or the like, and can maintain the self-cleaning property for a long time.

[0007]

In order to achieve the above object, the present invention has the following arrangement. That is, the protective film according to the present invention has a substrate in which a siliceous ceramic layer made of polysilazane or a modified product thereof is formed,
The photocatalyst-containing layer is formed on the outer surface.

The protective film according to the present invention has a photocatalyst containing layer containing a photocatalyst such as titanium dioxide formed on its outer surface. By sticking this protective film to a member or the like, dust or vehicle Even if contaminants such as exhaust gas adhere to the surface, the surface of the protective film is hydrophilized by the photocatalyst, so that the contaminants are effectively cleaned. Moreover, since it is only necessary to attach this protective film to the member or the like, it is much easier than in the past where it was necessary to form a photocatalyst containing layer, an intermediate layer, and a protective layer directly on the member surface, and even after installation. It can provide self-cleaning properties and also protects the members as a film.

Further, in the protective film according to the present invention, a siliceous ceramic layer made of polysilazane or a modified product thereof is formed between the substrate and the photocatalyst-containing layer on the outer surface. If a photocatalyst such as titanium dioxide has a strong oxidizing power as described above, if a base material is made of a synthetic resin such as polycarbonate, acrylic, PET, or urethane, or a metal that is weak in oxidation, even the base material may be used. It is oxidatively decomposed and its durability is impaired. Therefore, between the photocatalyst containing layer and the substrate,
By forming a silicone-based coating, durability can be improved. This silicone-based film is obtained by polymerizing a hydrolyzate of an alkoxysilane by a conventional sol-gel method. However, in this method, the weight is reduced during the film formation process and the shrinkage is large, so that a dense film is formed. Since it is difficult to form and is formed as a porous film, it is not enough to protect the substrate from the oxidative decomposition action of the photocatalyst, and sufficient heat resistance, bending resistance, abrasion resistance, etc. cannot be obtained. . On the other hand, in the protective film of the present invention, the coating of the siliceous ceramic layer made of polysilazane or a modified product thereof formed between the photocatalyst-containing layer and the base material increases in weight in the process of forming the coating and has a small shrinkage. Therefore, it is formed as a very dense coating, effectively protecting the base material of all materials from the decomposition action of the photocatalyst, and has excellent heat resistance, bending resistance, abrasion resistance and high coating hardness even in thin films. It is what you have.

Therefore, according to the present invention, since the siliceous ceramic layer made of polysilazane or a modified product thereof as described above is a very dense film, the substrate can be protected from the oxidative decomposition action of the photocatalyst even in a thin film. In addition, because of its excellent heat resistance, no cracks are generated even when the photocatalyst-containing layer is fired, and because of its excellent bending resistance, no cracks are generated even when it is curved. Since it can be easily attached to a member or the like, and has excellent durability and high coating film hardness even in a thin film, the substrate is hardly damaged.

As described above, in the present invention, since the base material is protected from the oxidative decomposition of the photocatalyst by the siliceous ceramic layer made of polysilazane or a modified product thereof, the material of the base material of the protective film is not particularly limited. Polycarbonate, acrylic, PET, any synthetic resin such as urethane, metal, etc. can be used, but in general, in a state of being attached to a member, it is transparent and thin so that it is not known that it is attached. A synthetic resin film which is rich in flexibility so as to conform to the shape is preferable. As described above, the base material is preferably a so-called film-shaped one that can correspond to any shape, but the thickness of the base material is not particularly limited, and is generally referred to as a sheet-like shape that is in the category of a wall thickness more than a film-like shape. It may be one that does not particularly have flexibility depending on the member to be attached.

The polysilazane in the present invention is not particularly limited, but preferably has at least a Si—H bond or an N—H bond in the molecule. Polysilazane may be used alone, or polysilazane and another polysilazane may be used. It may be a copolymer with a polymer or a mixture of polysilazane and another compound, and the polysilazane may be a chain, a ring, or a compound having a crosslinked structure. You may have at the same time,
These may be used alone or as a mixture.

The thickness of the siliceous ceramic layer made of polysilazane or a modified product thereof is preferably 0.02 to 5 μm, more preferably 0.05 to 2 μm, and if it exceeds 5 μm, the polysilazane is converted to a siliceous ceramic layer. Cracks may occur when converted to. To form the siliceous ceramic layer, a film-forming composition comprising polysilazane or a modified product thereof is spray-coated on a substrate, dip-coated, spin-coated, flow-coated, roll-coated, or a combination thereof. What is necessary is just to apply by an appropriate method and to convert it into a siliceous ceramic layer. The application may be performed once or two or more times.

After applying the coating composition,
In order to convert this coating film into a siliceous ceramic layer, heating and baking may be performed at a high temperature. However, when the substrate is formed from a synthetic resin such as polycarbonate or acrylic, the heating temperature is limited. The following method is preferred because it can be converted into a siliceous ceramic layer at a low temperature that does not cause deformation or deterioration of the synthetic resin as much as possible.

That is, a polysilazane or a modified product thereof is formed from a film-forming composition in which an amine or / and an acid is added, or an amine or / and an acid is added to the polysilazane or a modified product thereof. If the formed film-forming composition is formed by contacting with steam,
Low-temperature baking at about 70 ° C. is possible, and conversion to a siliceous ceramic layer can be performed at high speed.

In order to form a photocatalyst-containing layer containing a photocatalyst such as titanium dioxide on the outer surface, a thermal spraying method in which a powder such as titanium dioxide is melted and sprayed, or a CVD (chemically-produced) in which titanium dioxide is deposited through a chemical reaction. It may be formed by a suitable method such as a film method), a sputter evaporation method in which titanium dioxide or the like is sputter-evaporated and deposited, or a vacuum evaporation method. It is preferable to apply by a spray, a flow coater, or the like, since a uniform and smooth film is formed.

When the photocatalyst-containing layer is formed by such a method, it is preferable to use a silicone compound as a binder. By using a silicone-based compound, the resulting photocatalyst-containing layer has a high surface hardness and is not easily damaged, and also has chemical resistance due to a siloxane bond.
Because of its excellent stain resistance, it is hardly deteriorated even by activated titanium dioxide or the like, and also hardly causes contaminants to adhere thereto.

When the photocatalyst-containing layer is formed by using a silicone compound as a binder, for example, a coating composition comprising a mixture of a hydrolyzate of an alkoxysilane such as an organopolysiloxane or tetraethoxysilane and a titania sol is used as an example. Apply the object, 50 degrees ~ 20
It can be formed by heating at 0 degrees.

Titanium dioxide as a photocatalyst may be of rutile type, but is preferably of anatase type because of its high activity. This titanium dioxide has a wavelength range of 300 to 400 nm.
m is activated by irradiating ultraviolet light around m. The activation causes a strong oxidizing power to be developed, contaminants attached to the surface are decomposed, and the activation causes the surface to have a contact angle with water. Hydrophilization is performed to about 0 to about 20 degrees, and contaminants are less likely to adhere due to the hydrophilicity, and even if they adhere, they can be easily washed away by rainfall or the like.

[0020]

Next, an embodiment of the present invention will be specifically described with reference to the drawings. That is, FIG. 1 is a sectional view showing an embodiment of the present invention.

In the drawings, reference numeral 1 denotes a substrate made of a synthetic resin such as polycarbonate, acrylic, PET, urethane, or the like, or a metal such as aluminum or stainless steel. Reference numeral 2 denotes a siliceous ceramic layer formed on the substrate 1, and reference numeral 3 denotes a photocatalyst containing layer 3 formed on the outer surface thereof and containing a photocatalyst such as titanium dioxide. The siliceous ceramic layer 2 may be formed directly on the base material 1 or may be formed via another layer. If the photocatalyst containing layer 3 is formed on the outer surface, it may be formed directly on the siliceous ceramic layer 2 or may be formed via another layer.

By irradiating the photocatalyst containing layer 3 with ultraviolet rays, the photocatalyst is activated and the surface thereof is made hydrophilic, and contaminants attached to the surface due to rainfall or the like are washed. Note that an adhesive layer may be formed on the back surface of the base material 1 so as to be easily attached to the member, or may be attached by thermal lamination. The substrate 1 may be appropriately colored, but is preferably transparent so as not to obscure the color tone of the member to be stuck and to be inconspicuous. When the base material 1 is made transparent, the photocatalyst containing layer 3 is preferably formed as thin as possible so as not to impair the see-through performance of the base material 1.

Ultraviolet rays for activating the photocatalyst may be received from sunlight outdoors. However, the photocatalyst is activated by irradiating the photocatalyst with ultraviolet rays in a factory or the like using black light or the like. May be in a state where the surface is made hydrophilic.

[0024]

Embodiments of the present invention will be described below.

(Example) The following coating agent was applied to a transparent synthetic resin film (thickness: 0.5 mm) made of polycarbonate. Perhydropolysilazane was dissolved in decahydronaphthalene and adjusted to a concentration of 20% by weight.
200 mg of tri-n-pentylamine was gradually added to 10 g of this solution at room temperature with stirring. This was applied on the polycarbonate in the atmosphere by flow coating. This was heated at 100 ° C. and a relative humidity of 90% for 1 hour to obtain a siliceous ceramic layer. The thickness of this siliceous ceramic layer was 0.5 μm.

Next, 56 parts by weight of an anatase type titanium oxide sol (Nissan Chemical Co., Ltd., TA-15, solid content 15 wt%),
Silica sol (Nippon Synthetic Rubber, Glasca A solution, solid content 20
After mixing 33 parts by weight), 11 parts by weight of methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution) and ethanol were added, and the mixture was further stirred for 2 hours to partially hydrolyze methyltrimethoxysilane. It was adjusted by a dehydration condensation polymerization reaction. This was flow-coated to form a photocatalyst-containing layer on the siliceous ceramic layer.

Next, the surface of the obtained sample was irradiated with 1.5 mw / cm 2 using a black light blue fluorescent lamp.
UV light was irradiated at an illuminance of 48 hours. Thereafter, the contact angle of the surface with water was measured and found to be 5 degrees or less on average.
In addition, the total light transmittance of the obtained film was 93%,
The haze was 0.2%.

(Comparative Example) The following coating agent was applied to a transparent synthetic resin film (thickness: 0.5 mm) made of polycarbonate. After mixing 3 parts by weight of silica sol (Nippon Synthetic Rubber, Glasca A solution, solid content 20 wt%), methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution) 1
A part by weight and ethanol were added, and the mixture was further stirred for 2 hours, and adjusted by partially subjecting methyltrimethoxysilane to a hydrolysis reaction and a dehydration-condensation polymerization reaction. This was applied to the above polycarbonate by flow coating, and 120
By heating at 50 ° C. for 50 minutes, a siliceous ceramic layer was obtained by a sol-gel method as a conventional technique. The thickness of this siliceous ceramic layer was 1.0 μm.

Next, 56 parts by weight of an anatase type titanium oxide sol (Nissan Chemical Co., TA-15, solid content 15 wt%),
Silica sol (Nippon Synthetic Rubber, Glasca A solution, solid content 20
After mixing 33 parts by weight), 11 parts by weight of methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution) and ethanol were added, and the mixture was further stirred for 2 hours to partially hydrolyze methyltrimethoxysilane. It was adjusted by a dehydration condensation polymerization reaction. This was flow-coated to form a photocatalyst-containing layer on the siliceous ceramic layer by the sol-gel method.

Next, the surface of the obtained sample was 1.5 mw / cm 2 using a black light blue fluorescent lamp.
UV light was irradiated at an illuminance of 48 hours. Thereafter, the contact angle of the surface with water was measured and found to be 5 degrees or less on average.
The resulting film had a total light transmittance of 89% and a haze of 0.7%.

The coating properties of the above Examples and Comparative Examples were compared by the following tests.

(Test 1) Anti-decomposition property for photocatalyst-containing layer A sample obtained in the example and a sample obtained in the comparative example were subjected to a super energy irradiation tester (Suga tester UE-1DEc).
UV light for 240 hours. As a result, cracks were observed in the siliceous ceramic layer in the comparative example, but no abnormality was observed in the siliceous ceramic layer in the example.

(Test 2) Heat Resistance The sample obtained in the example and the sample obtained in the comparative example were heated at 130 ° C. for 2 hours. As a result, cracks were observed in the siliceous ceramic layer in the comparative example. In contrast, no abnormality was observed in the siliceous ceramic layer in the examples.

(Test 3) Bending Resistance A sunshine weather meter test was performed on the sample obtained in the example and the sample obtained in the comparative example while being bent to a radius of 2000 mm. As a result, in the sample of the comparative example, fine cracks were observed on the surface after 100 hours, whereas in the example, no abnormality was observed after 500 hours.

(Test 4) Abrasion Resistance A pencil hardness test was performed to compare the abrasion resistance of the sample obtained in the example with the sample obtained in the comparative example. As a result, the sample of the comparative example had a pencil hardness of F to H, whereas the example had a pencil hardness of 2H to 3H.

As described above, since the siliceous ceramic layer made of polysilazane or a modified product thereof is a very dense film, it has a function of protecting the base material from the decomposition action of the photocatalyst and has a high heat resistance, bending resistance, and abrasion resistance. It is excellent, and since it can be made into a thin film, it also has excellent light transmittance, and it is confirmed that it is suitable for a protective film.

[0037]

The protective film according to the present invention has a photocatalyst-containing layer containing a photocatalyst such as titanium dioxide formed on its outer surface. By sticking this protective film to a member or the like, the surface of the protective film is exposed to dust. Even if contaminants such as vehicle and vehicle exhaust gas adhere to the surface, the surface of the protective film is hydrophilized by the photocatalyst, so that the contaminants are effectively cleaned. Moreover, since it is only necessary to attach this protective film to the member or the like, it is much easier than in the past where it was necessary to form a photocatalyst containing layer, an intermediate layer, and a protective layer directly on the member surface, and even after installation. It can provide self-cleaning properties and also protects the members as a film.

Further, according to the present invention, a siliceous ceramic layer made of polysilazane or a modified product thereof is formed between a substrate and a photocatalyst-containing layer, and the siliceous ceramic layer made of polysilazane or a modified product thereof is very dense. Because it is a thin film, the base material is protected from the oxidative decomposition action of the photocatalyst even in a thin film, and because it has excellent heat resistance,
No cracks occur even during firing of the photocatalyst containing layer,
In addition, since it has excellent flex resistance, it does not crack even when it is curved, can be easily attached to members of any shape, etc., has excellent durability, and has high coating hardness even in a thin film. The base material is less likely to be scratched.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 base material 2 siliceous ceramic layer 3 photocatalyst containing layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F100 AA21 AD00A AD04A AD09A AK45 AL06A AT00C BA03 CC00 EJ01 EJ54 EJ58 EJ91 GB07 GB08 GB90 JL06 JL08B JM01 JN01

Claims (3)

[Claims] 1. A protective film comprising: a base material, a siliceous ceramic layer made of polysilazane or a modified product thereof formed thereon, and a photocatalyst-containing layer formed on an outer surface. 2. The protection according to claim 1, wherein the siliceous ceramic layer is formed from a composition for forming a coating film in which amines and / or acids are added to polysilazane or a modified product thereof. Film. 3. The siliceous ceramic layer is formed by contacting a film-forming composition obtained by adding amines and / or acids to polysilazane or a modified product thereof with water vapor. The protective film according to claim 1.