JP4156821B2 - Photocatalyst-coated acrylic film and photocatalyst-coated laminate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photocatalyst-coated acrylic film excellent in transparency (high transparency) and a photocatalyst-coated laminate.
[0002]
[Prior art]
Acrylic films are used as surface coating materials for various products because of their excellent transparency and strength. However, there is a problem that the solvent resistance such as alcohols is poor, and the surface hardness is low, so that it is easily scratched.
On the other hand, a photocatalyst is a substance having a photocatalytic function that decomposes an organic substance or exhibits functions such as super hydrophilicity by irradiation with ultraviolet rays. Since it has effects such as antibacterial, deodorizing, and antifouling, it is being used in various fields. As a photocatalyst, anatase type titanium dioxide and the like are known. Attempts have been made to blend such photocatalyst particles into a synthetic resin film and to mold the resultant, and to give the resultant synthetic resin film a photocatalytic function.
[0003]
[Problems to be solved by the invention]
However, in the molded product obtained by blending and molding the photocatalyst particles in the synthetic resin film as described above, the photocatalyst particles located inside the base material sufficiently exhibit the function expected as a photocatalyst. There is a problem that it cannot be performed or the transparency of the synthetic resin film is impaired.
[0004]
The present invention has been made in consideration of the above circumstances, and is a photocatalyst capable of maintaining excellent transparency, which is a characteristic of an acrylic film, having a photocatalytic function, and improving solvent resistance and surface hardness. An object of the present invention is to provide a coated acrylic film, and to provide a photocatalyst-coated laminate excellent in transparency or surface gloss, in which such a photocatalyst-coated acrylic film is laminated.
[0005]
[Means for Solving the Problems]
The present invention comprises a photocatalyst film formed on the surface of an acrylic film having a thickness of 10 to 100 μm via an underlayer,
The photocatalyst film, the average particle size 4～30Nm, and 0.2 to 15 wt% only a specific surface area of 200 meters ² / g or more titanium dioxide particles, silica compounds as the binder component (as SiO ₂₎ 0.1 as titanium dioxide particles titanium dioxide-containing coating solution containing a 5% by weight, was formed to a thickness of 0.04~0.4μm by drying by coating with coating amount of 0.1 to 10 g / m ^2, the photocatalytic coating Acrylic film.
[0006]
In the above invention, the silica compound is preferably an alkoxysilane or a condensate or a hydrolyzate thereof.
[0007]
Moreover, it is preferable that the said base layer is what has an acrylic resin, an acrylic modified silicone resin compound, or a silicon modified acrylic resin compound as a main component.
[0008]
Moreover, this invention is a photocatalyst coat laminated body formed by laminating | stacking the said photocatalyst coat acrylic film on a base material. This photocatalyst-coated laminate can be obtained by laminating a photocatalyst-coated acrylic film on a base material without using an adhesive by thermal lamination or extrusion lamination.
Furthermore, the present invention is a photocatalyst-coated polycarbonate plate obtained by laminating the photocatalyst-coated acrylic film on a polycarbonate plate without using an adhesive.
Furthermore, the present invention is a photocatalyst-coated decorative metal plate obtained by laminating the photocatalyst-coated acrylic film on a metal plate.
Furthermore, the present invention is a photocatalyst-coated rain gutter obtained by laminating the photocatalyst-coated acrylic film on the surface of the gutter.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The acrylic film used in the present invention is a film made of an acrylic resin, and the acrylic resin refers to a resin obtained by polymerizing acrylic acid and its derivatives. Polymers and copolymers such as acrylic acid, acrylic acid ester, acrylamide, acrylonitrile, methacrylic acid, and methacrylic acid ester are included. Typical examples include polymethyl methacrylate (PMMA) and polyacrylate. The thickness of the acrylic film is usually about 10 to 100 μm, but is not particularly limited.
[0010]
In the present invention, the photocatalyst film is formed on the surface of the acrylic film via a base layer. The photocatalytic film comprises titanium dioxide containing 0.2 to 15% by weight of titanium dioxide particles having an average particle size of 4 to 30 nm and a specific surface area of 200 m ² / g or more, and 0.1 to 5% by weight of a silica compound (as SiO ₂ ). The coating solution is formed by applying the coating solution at a coating amount of 0.1 to 10 g / m ² and drying. If it is out of the range of this condition, the function of the photocatalyst is not exhibited effectively, or the excellent transparency which is a characteristic of the acrylic film is lost.
[0011]
Anatase type titanium dioxide, which is a photocatalyst, is preferably used, but rutile type or brookite type titanium dioxide may be included. A surface treatment may be performed. Other photocatalysts may be appropriately mixed and used as long as the transparency is not impaired.
[0012]
The silica compound contained in the titanium dioxide-containing coating solution is a binder component that improves the adhesion of the photocatalyst particles and improves the strength of the photocatalyst film. A silica compound (as SiO ₂ ) is included in an amount of 0.1 to 5% by weight based on the titanium dioxide-containing coating solution. If the amount is larger than this, the stability of the coating solution is inhibited, and the photocatalytic effect is lowered.
[0013]
As the silica compound, 4, 3, and bifunctional alkoxysilanes, and condensates, hydrolysates, silicone varnishes, and the like of these alkoxysilanes can be used. Specifically, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane as tetrafunctional alkoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, Vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, glycidpropoxytrimethoxysilane, glycylpropylpropyldiethoxysilane, aminopropyltriethoxysilane, aminoethylaminopropyltrimethoxysilane, mercaptopropyltrimethoxy Silanes, bifunctional alkoxysilanes include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyl Such as diethoxy silane. Examples of condensates include, but are not limited to, condensates of tetrafunctional alkoxysilanes such as ethyl silicate 40, ethyl silicate 48, and methyl silicate 51. Moreover, as a hydrolyzate, what hydrolyzed the alkoxysilane using the organic solvent, water, and the catalyst can be used.
[0014]
Among these silica compounds, tetramethoxysilane, tetraethoxysilane, ethyl silicate 40, ethyl silicate 48, methyl silicate 51, and alcoholic silica sol as a hydrolysis product thereof can fix the film firmly and relatively It is particularly suitable because it is inexpensive.
[0015]
The production method of the alcoholic silica sol is not particularly limited, and the alkoxysilane may be hydrolyzed in the coating solution, or the alkoxysilane is hydrolyzed or partially hydrolyzed to become an alcoholic silica sol. Things may be added to the coating solution.
[0016]
These binder components are used by being mixed with a coating solution. In mixing the binder, a solvent can be used to mix and stabilize the binder component and the aqueous titanium dioxide dispersion. As the type of solvent, monohydric lower alcohols such as methanol, ethanol, propanol and butanol, polyhydric alcohols such as ethylene glycol and propylene glycol, and cellosolve which is an ester thereof can be used as good solvents. The amount of these solvents is preferably 5 to 90% by weight based on the entire coating solution.
[0017]
The base layer applied to the surface of the acrylic film is preferably one having high affinity for both the acrylic film and the photocatalytic film. The adhesion between the acrylic film and the photocatalytic film is further enhanced by the underlayer. The base layer is preferably composed mainly of an acrylic resin, an acrylic-modified silicone resin compound, or a silicon-modified acrylic resin compound. An acrylic resin as the main component is preferable because it can form a strong adhesive layer with high adhesion. In order to further increase the adhesion, an organic silicon compound such as silica sol, silicone resin, alkoxysilanes, or a condensate of alkoxysilanes (alkyl silicate) can be mixed with an acrylic resin. Moreover, it can replace with an acrylic resin and an acrylic modified silicone resin compound and a silicone modified acrylic resin compound can also be used.
[0018]
The underlayer is generally formed by applying a solution containing the resin compound. The solution may be one in which a resin is dispersed in a solvent such as toluene, xylene, ketone, alcohol, or an aqueous emulsion type. The method for coating and applying the underlayer to the synthetic resin layer is not particularly limited, and various coating methods such as brush coating, spray coating, spin coating, dip coating, roll coating, gravure coating, and bar coating can be selected. It is preferable to use a gravure roll coater. Although application | coating of a base layer is not limited, in order to acquire sufficient adhesiveness, it apply | coats by the coating amount of 0.1-10 g / m < ² >, Preferably 0.2-2 g / m < ² > in the state before drying. The thickness of the coating after drying is preferably 0.04 to 0.4 μm.
[0019]
A titanium dioxide-containing coating solution is applied onto the underlayer and dried to form a photocatalytic film. As the method of applying the titanium dioxide-containing coating solution, various coating methods can be selected as in the case of the above-described underlayer. The coating solution is usually dried at 80 ° C. or lower.
[0020]
Coating of the titanium dioxide-containing coating solution, as described above, 0.1 to 10 g / m ² in a state before drying, preferably applied at a coating weight of 0.2 to 2 g / m ^2. The thickness of the coating after drying is preferably 0.04 to 0.4 μm. The application may be performed in a plurality of times. In general, a thicker film can enhance the photocatalytic effect. However, if the thickness exceeds 2 μm, the increase in the film thickness is not proportional to the increase in the photocatalytic effect, so that a film thickness greater than this is generally uneconomical. Moreover, since transparency will be impaired or a crack will be caused when a film thickness is thick, it is set as the said range.
[0021]
The photocatalyst-coated acrylic film according to the present invention is suitable as a surface coating material, and can be laminated on a substrate so that the photocatalyst film is located on the surface side to form a photocatalyst-coated laminate, which can be applied to various products. Examples of the substrate include synthetic resin materials and metal plates. Examples of the synthetic resin material include polycarbonate, ABS resin, polystyrene, polyethylene terephthalate, acrylic resin, vinyl chloride resin, film, sheet made of polyolefin, fluororesin, polyamide, polyimide, and the like. Examples of the metal plate include various steel plates and aluminum alloy plates. The photocatalyst-coated laminate can be used as, for example, exterior materials for buildings such as entrance doors and rain gutters, interior materials such as washstands, baths, and toilet units, and automotive interior materials.
[0022]
The method for producing the photocatalyst-coated laminate of the present invention is not particularly limited, but it is easy to manufacture by laminating on a base material without using an adhesive by thermal lamination or extrusion lamination (extrusion coating). Is useful.
[0023]
The photocatalyst-coated polycarbonate plate obtained by laminating the photocatalyst-coated acrylic film according to the present invention on a polycarbonate plate without using an adhesive has excellent transparency and weather resistance, and is composed of a single polycarbonate plate. The yellow discoloration that occurs in this case can be suppressed. This photocatalyst-coated polycarbonate plate is suitably used as a corrugated plate that can be applied to various roofing materials, for example.
[0024]
The photocatalyst-coated polycarbonate plate can be easily produced by thermal lamination or extrusion lamination (extrusion coating). That is, the polycarbonate as a base material is melt-extruded from a die, cooled to form a sheet, and then reheated with a heater to raise the temperature to about 130 ° C., and the photocatalyst-coated acrylic already obtained by thermal lamination. Laminate with film. Or the polycarbonate which is a base material is melt-extruded from a die | dye, and is laminated | stacked with the already obtained photocatalyst coat acrylic film by extrusion lamination (extrusion coating).
[0025]
In addition, the photocatalyst-coated decorative metal plate of the present invention obtained by laminating the above-mentioned photocatalyst-coated acrylic film on a steel plate or other metal plate exhibits a photocatalytic function and has excellent gloss, Useful.
[0026]
In addition, the photocatalyst-coated rain gutter obtained by laminating the photocatalyst-coated acrylic film on the (at least) surface (outer surface) of the gutter effectively exhibits antifouling effects and other photocatalytic functions, and has an excellent gloss feeling It is useful as a rain gutter. As such a rain gutter base material, a metal plate such as a steel plate is suitable, but a synthetic resin material can also be used. For example, a rain gutter using a metal plate such as a steel plate can be manufactured by laminating the photocatalyst-coated acrylic film on a metal plate such as a steel plate by a heat laminating method and then bending it.
[0027]
The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and can be implemented with appropriate modifications and additions within the scope of the gist of the present invention.
[0028]
【Example】
[Example 1]
On the surface of an acrylic film (Kanebuchi Chemical Co., Ltd., trade name “Sanduren 004-NST”, thickness 50 μm), 5 g / m ² of Taki Chemical Co., Ltd. After coating and drying, 5 g / m ^{2 of a} titanium dioxide-containing coating solution (trade name “CZP-221”, manufactured by Taki Chemical Co., Ltd.) is coated thereon and dried to obtain a transparent photocatalyst-coated acrylic film. It was.
[0029]
“Tynoc primer A” is composed of 20% silicon-modified resin as solid content, 30% colloidal silica, 20% ethanol as solvent, 20% 2-propanol, and 10% pure water.
[0030]
“CZP-221” was prepared by preparing 80 parts by weight of anatase-type titanium dioxide sol, 150 parts by weight of ethanol, 150 parts by weight of isopropyl alcohol, 550 parts by weight of pure water, and 70 parts by weight of tetraethoxysilane. did.
[0031]
Note that both the underlayer and the photocatalytic film were formed using a gravure roll coater with a roll speed of 50 m / min, a drying temperature of 80 ° C., and a drying time of 30 seconds. The film thicknesses of the underlying layer and the photocatalyst film after drying were both 0.05 μm.
[0032]
On the sample piece obtained by cutting the photocatalyst-coated acrylic film obtained in Example 1 into a 10 cm square, an oil (n-octadecane) was dropped as a decomposition target and uniformly stretched, and then 1 mW / cm ² from above. -Irradiated with ultraviolet rays having a strength of sec, and the residual ratio of oil over time was measured. The result is shown in FIG. In the examples, the photocatalytic activity was exhibited over time, and the oil was decomposed. In addition, although the sample piece by the acrylic film single-piece | unit which has not given the base layer and the photocatalyst film was made into the comparative example, the oil residual rate did not change.
[0033]
Further, a 95% ethanol solution was dropped on the sample piece, allowed to stand for 3 hours, rinsed with tap water, dried at room temperature, and after drying, the state of the film was judged visually.
Although the thing of an Example was the same as before dropping, and remained transparent, the thing of the comparative example had the acrylic invaded by ethanol, and the film became cloudy.
[0034]
Moreover, the surface hardness was determined about the sample piece of an Example and a comparative example. The determination was made based on the scratch hardness with a pencil. In the example, the scratch hardness was H, while in the comparative example, only B.
[0035]
【The invention's effect】
According to the photocatalyst-coated acrylic film of the present invention, it exhibits excellent appearance while maintaining excellent transparency, which is a characteristic of the acrylic film, and a photocatalytic film having high film strength is formed, thereby exhibiting an excellent photocatalytic function. . Furthermore, solvent resistance and surface hardness can be improved, and durability is excellent and it is hard to be damaged.
[0036]
Further, by laminating such a photocatalyst-coated acrylic film on a substrate, a photocatalyst-coated laminate excellent in transparency or surface gloss is provided. This photocatalyst-coated laminate is easy to manufacture and costs can be reduced by laminating a photocatalyst-coated acrylic film on a base material without using an adhesive by thermal lamination or extrusion lamination.
[0037]
Furthermore, the photocatalyst-coated polycarbonate plate made by laminating the photocatalyst-coated acrylic film on the polycarbonate plate without using an adhesive has excellent transparency and excellent weather resistance. The yellow discoloration that occurs can be suppressed. Easy to manufacture.
[0038]
The photocatalyst-coated decorative metal plate of the present invention obtained by laminating the photocatalyst-coated acrylic film on a steel plate or other metal plate exhibits a photocatalytic function, has an excellent gloss, and has a high-grade appearance. It is useful as a decorative metal plate.
[0039]
In addition, the photocatalyst-coated rain gutter obtained by laminating the photocatalyst-coated acrylic film on the surface of the gutter effectively exhibits an antifouling effect and other photocatalytic functions, has an excellent gloss, It is useful as a gutter with a certain appearance.
[Brief description of the drawings]
FIG. 1 is a graph showing the results of an oil decomposability test of an example.

Claims (8)

A photocatalytic film is formed on the surface of an acrylic film having a thickness of 10 to 100 μm via an underlayer,
The photocatalyst film, the average particle size 4～30Nm, and 0.2 to 15 wt% only a specific surface area of 200 meters ² / g or more titanium dioxide particles, silica compounds as the binder component (as SiO ₂₎ 0.1 as titanium dioxide particles A photocatalyst coat formed to a thickness of 0.04 to 0.4 μm by coating a titanium dioxide-containing coating solution containing ˜5 wt% with a coating amount of 0.1 to 10 g / m ² and drying. Acrylic film.   The photocatalyst-coated acrylic film according to claim 1, wherein the silica compound is alkoxysilane or a condensate or a hydrolyzate thereof.   3. The photocatalyst-coated acrylic film according to claim 1, wherein the base layer is mainly composed of an acrylic resin, an acrylic-modified silicone resin compound, or a silicon-modified acrylic resin compound.   The photocatalyst coat laminated body formed by laminating | stacking the photocatalyst coat acrylic film in any one of Claims 1-3 on a base material.   The photocatalyst coat laminated body of Claim 4 which laminated | stacked the photocatalyst coat acrylic film on the base material without the adhesive agent by thermal lamination or extrusion lamination.   A photocatalyst-coated polycarbonate plate obtained by laminating the photocatalyst-coated acrylic film according to any one of claims 1 to 3 on a polycarbonate plate without using an adhesive.   A photocatalyst-coated decorative metal plate obtained by laminating the photocatalyst-coated acrylic film according to claim 1 on a metal plate.   A photocatalyst-coated rain gutter obtained by laminating the photocatalyst-coated acrylic film according to claim 1 on the surface of the gutter.

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