JP2008158120A - Film for pasting window - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an efficient and inexpensive film for pasting a window, which suppresses a glaring phenomenon. <P>SOLUTION: The film for pasting the window has been invented from an idea that reflected light is not biased in a specific direction by diffusing reflected light. The film for pasting the window is characterized by that a metallic thin film layer is provided at least to one surface of a base material film; vertical reflectivity at 400 to 800 nm wavelength is 30% or less; total light transmittance is 20% or more and further haze is 50% or more. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a window pasting film, and more particularly to a window pasting film in which a glare phenomenon is suppressed as compared with a conventional window pasting film.

  2. Description of the Related Art Conventionally, a window pasting film in which a transparent plastic film is used as a base and a metal thin film layer made of aluminum, chromium, nickel, silver or the like is provided on one side of the plastic film is widely known. This is used for the windows of vehicles such as automobiles, buses, trains, airplanes, ships, etc., and windows of buildings such as houses and buildings. (1) Even if the glass is destroyed due to a disaster, the broken pieces are scattered. (2) Visible light is allowed to pass to some extent, but effects such as (3) electromagnetic wave shielding, (4) dew condensation prevention, etc. are obtained, blocking light from the near infrared part to the infrared part.

Examples of conventionally proposed window pasting films include the following. For example, Japanese Utility Model Publication No. 56-16562 discloses a light-adjusting film for attachment in which a vapor-deposited film of metal such as aluminum or copper is formed on a transparent film. Japanese Patent Application Laid-Open No. 2000-177044 discloses a laminated film in which a translucent metal vapor deposited film and a zinc sulfide vapor deposited film are laminated on a transparent film and have a specific visible light transmittance and ultraviolet blocking rate. Japanese Patent Application Laid-Open No. 6-270323 discloses a window pasting film in which a reflected light in which a translucent metal vapor deposition film, a metal compound transparent vapor deposition film, and a semitransparent metal vapor deposition film are laminated on one side of a transparent film has an iris gloss. Yes. Japanese Patent Application Laid-Open No. 2001-146440 discloses a laminated glass having a high visible light transmittance and a low visible light reflection purity by combining a zinc oxide layer, a silver layer, and a tin oxide layer. In Patent Documents 2, 3, and 4, there is a method of improving the transmittance by reducing the reflectance in the visible light region by the light interference effect by combining the metal film and the transparent dielectric.

Japanese Utility Model Publication No. 56-16562 JP 2000-177044 A JP-A-6-270323 JP 2001-146440 A

When a window pasting film is pasted on, for example, a window glass, a glare phenomenon occurs in which reflected light such as sunlight or illumination enters the eyes, giving an unpleasant feeling. In the prior art shown in the previous section, the reflectance is lowered by using optical interference, and in some cases, a certain degree of effect may be shown for preventing glare. However, with such an optical interferometry method, it is necessary to use a considerably large number of multilayer films in order to completely suppress the reflectivity at all wavelengths in the visible light region. A multilayer film with one to several layers has a certain wavelength. Even if the reflectance at is suppressed, reflection at other wavelengths remains, and it has reflected light of a specific color. In this case, it is necessary to adjust the thickness of each layer as intended and to form it uniformly. In order to form it on a plastic film, it is necessary to control the film thickness in multiple layers in the width direction and the length direction, resulting in a very high manufacturing cost.

In order to eliminate the above problems, an object of the present invention is to provide a window pasting film that is low in cost and suppressed in the glare phenomenon.

  The film for window pasting of this invention was made | formed in order to eliminate the said problem, and was considered from the idea that reflected light is not biased in the specific direction which diffused reflected light. That is, a metal thin film layer is provided on at least one surface of the base film, the vertical reflectance at a wavelength of 400 nm to 800 nm is 30% or less, the total light transmittance is 20% or more, and haze is further generated. It is a film for window pasting characterized by being 50% or more.

Preferably, in the above invention, the window pasting film is characterized in that the vertical reflectance at a wavelength of 400 nm to 800 nm is 10% or less and the vertical reflectance at a wavelength of 800 nm to 2500 nm is 50% or less. By suppressing the vertical reflectance at a wavelength of 800 nm to 2500 nm to 50% or less, a window pasting film capable of diffusing heat rays in the near infrared region and preventing the heat from concentrating at a specific place is obtained.

  In addition, it is preferable to use a plastic film that has been subjected to sandblasting on the surface on which the metal thin film layer is provided as the base film in the above invention in terms of diffusing reflected light and suppressing glare.

In order to improve the transmittance in the visible light region, it is preferable to provide a metal thin film layer and a dielectric layer on at least one surface of the base film. For example, a layer structure of base film / metal thin film layer / dielectric layer, base film / dielectric layer / metal thin film layer / dielectric layer, or the like is used. These film thicknesses are determined by the type of metal thin film layer and dielectric layer used and the required required characteristics.

It has high visible light transmittance, including scattered light, and high near-infrared reflectance, and the reflected light is diffused, causing glare phenomenon in the visible light region and temperature rise in specific places in the near-infrared region. A window pasting film that can be suppressed is provided.

The material of the base film used in the present invention is not particularly limited, and is intended to achieve the purpose for pasting a window, etc., and has heat resistance capable of forming a thin film layer by a sputtering method or a vacuum deposition method. Specifically, polyethylene terephthalate film, polypropylene film, polyethylene film, polyamide film, polyimide film and the like are preferable. In order to satisfy the vertical reflectance and the total light transmittance of the first aspect of the substrate film, it is necessary that the surface on the side where the metal thin film layer is provided is rough. Examples of the method include a method of sandblasting the surface, or a method of coating the surface of the base film with a resin containing fine particles and powder such as titanium oxide and silicon oxide. Further, there are a method of adding inorganic fine particles when forming a base film, or a method of forming a cavity by foaming. Among these, sandblasting has the best performance for increasing haze, and is most preferable in terms of adhesion between laminated films and productivity. Further, the base film may be one whose surface has been subjected to surface treatment such as corona discharge treatment or low-temperature plasma treatment, and is generally preferred because it can improve the adhesion between the plastic film and the metal thin film layer. . For this same purpose, some anchor layer may be provided.

The thickness of the base film is preferably in the range of 5 μm to 250 μm, particularly 10 μm to 100 μm. If the thickness is less than 5 μm, not only wrinkles are likely to occur during film formation and problems are likely to occur in the production process, but the strength is lowered and scattering prevention characteristics and the like are not sufficient. On the other hand, when the thickness exceeds 250 μm, workability is deteriorated and handling as a long roll product becomes difficult, which is not appropriate.

Next, there is no restriction | limiting in particular as a metal thin film layer used for this invention, Specifically, metal substances, such as Au, Ag, Cu, Al, Cr, Ni, stainless steel, are preferable. In addition to preventing glare, a film for window pasting has a high visible light transmittance including scattered light, while it preferably has a high reflectance in the near infrared region, and in that sense, it absorbs in these regions. Ag and Al with less content are preferred. Cr, Ni, and stainless steel are preferably used in applications where solar ray shielding by absorption or durability is important. In addition, a metal thin film layer may use 2 or more types of metal substances by an alloy or laminated structure as needed.

A known technique can be used as a method for forming the metal thin film layer. In particular, vacuum deposition or sputtering is preferred.

The thickness of the metal thin film layer is set so that the vertical reflectance of the window pasting film of the present invention at a wavelength of 400 nm to 800 nm is 30% or less and the total light transmittance is in the range of 20% or more. It is necessary. The thickness of the metal thin film layer that satisfies this requirement varies depending on the type of metal and also depends on the combination with the dielectric layer, and cannot be determined in general. In general, it is preferably in the range of 1 nm to 50 nm, particularly in the range of 3 nm to 20 nm. If the thickness is too thin, the metal thin film layer will not be a continuous layer, so the near infrared and infrared reflectance will be low and it will be difficult to exert a sufficient heat ray reflection effect. Is not appropriate because it gets worse.

The dielectric layer used in the present invention is preferably a layer made of a dielectric material having a high refractive index in order to suppress reflection of visible light and enhance transmission characteristics. _{TiO 2,} Ta ₂ O _{5 Specifically, ZrO 2, SnO, In 2} O 3 , and ZnO are preferable. Organic substances may be mixed in these dielectrics, but if this amount is large, the refractive index is lowered, which is not preferable. Examples thereof include TiO ₂ or ZrO ₂ derived from an organic compound obtained by hydrolysis of alkyl titanate or alkyl zirconium, or an organic / inorganic hybrid material having nano-sized dielectric fine particles. Since these are formed by a coating method, they are particularly preferable because they are excellent in workability.

As a method for forming the dielectric layer, a known technique such as a dry coating method or a wet coating method can be used. As a forming method of the dry coating method, a vacuum coating method or a sputtering method, and as a forming method of the wet coating method, a bar coating method, a doctor blade method, a reverse roll coating method, or a gravure roll coating method is used.

The thickness of the dielectric layer should be set so that the vertical reflectance of the window pasting film of the present invention at a wavelength of 400 nm to 800 nm is 30% or less and the total light transmittance is in the range of 20% or more. is required. This thickness varies depending on the type and configuration of the material and is not generally determined, but is generally in the range of 1 nm to 100 nm, and particularly preferably in the range of 5 nm to 80 nm. In order to improve the transmittance in the visible light region, it is preferable to provide a metal thin film layer and a dielectric layer on at least one surface of the base film. For example, a layer structure of base film / metal thin film layer / dielectric layer, base film / dielectric layer / metal thin film layer / dielectric layer, or the like is used.

In the window pasting film of the present invention, a protective layer for enhancing scratch resistance and durability may be provided on the above-mentioned base film, metal thin film layer or dielectric layer. There is no restriction | limiting in particular as a protective layer used for this invention. A known hard coat agent may be used for the scratch resistance. Specifically, urethane-acrylate type, epoxy acrylate type, polyester-acrylate type and the like are preferable. In order to improve durability, an optimum material is selected depending on each configuration.

As a method for forming the protective layer, a known coating method can be used, and a bar coating method, a doctor blade method, a reverse roll coating method, and a gravure roll coating method are preferable.

The thickness of the protective layer is preferably in the range of 0.5 μm to 10 μm, particularly in the range of 1 μm to 5 μm. If the thickness is less than 0.5 μm, the scratch resistance function as a protective layer tends to be insufficient, and if it exceeds 10 μm, not only the cost increases but also the film stress increases and curling occurs. Not.

The protective layer may be formed by directly coating the surface of the window pasting film of the present invention, or by laminating, for example, a hard-coated polyester film with an acrylic or urethane adhesive.

In order to affix the window pasting film of the present invention to a window or the like, an adhesive layer may be provided on the surface of the window pasting film opposite to the side on which the protective layer is formed. There is no restriction | limiting in particular as an adhesion layer used for this invention, What is necessary is just to use a well-known adhesive. Specifically, acrylic or silicone adhesives are preferred. In view of light resistance, cost, and the need to peel off the film for window pasting, it is particularly preferable to use an acrylic system. The acrylic pressure-sensitive adhesive used in the present invention may be either solvent-based or emulsion-based, but is preferably a solvent-based pressure-sensitive adhesive because it is easy to increase the adhesive strength and the like, and among them, those obtained by solution polymerization are particularly preferable. For example, a stabilizer, an ultraviolet absorber, a flame retardant, an antistatic agent and the like can be contained in the pressure-sensitive adhesive as additives.

As a method for forming the adhesive layer, a known coating method can be used, and a bar coating method, a doctor blade method, a reverse roll coating method, and a gravure roll method are preferable.

The thickness of the adhesive layer is preferably in the range of 1 μm to 50 μm. Since the adhesive strength depends on the thickness of the pressure-sensitive adhesive, the thickness of the pressure-sensitive adhesive layer is required to some extent. If the thickness is less than 1 μm, it is partially combined with the thickness unevenness of the window pasting film, for example, with window glass. Insufficient contact is difficult, and it is difficult to obtain the necessary adhesive force. When the thickness exceeds 50 μm, the cost is increased and sufficient curing is not performed during processing. It is not appropriate because cohesive failure occurs between the adhesive layers and the adhesive remains.

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the examples.

  Using a sand matte film (thickness 50μm, PS type) made of Teijin DuPont film that has been sandblasted to biaxially stretched polyethylene terephthalate film, an isopropanol solution of tetrabutyl titanate is applied to the treated surface by a gravure coating method. The dielectric layer 1 having a thickness of 30 nm was formed by drying. On this dielectric layer, an Ag metal thin film layer was formed to a thickness of 10 nm by sputtering. An isopropanol solution of tetrabutyl titanate was again applied on the metal thin film layer by a gravure coating method and dried to form a dielectric layer 2 having a thickness of 50 nm.

  Using a sand matte film (thickness 50 μm, PS type) made of Teijin DuPont film that has been sandblasted to biaxially stretched polyethylene terephthalate film, an Ag metal thin film layer is formed to a thickness of 10 nm on this treated surface by sputtering. Formed to be. On this metal thin film layer, an isopropanol solution of tetrabutyl titanate was applied by a gravure coating method and dried to form a dielectric layer 2 having a thickness of 50 nm.

Using a sand matte film (thickness 50 μm, PS type) made of Teijin DuPont film that has been sandblasted to biaxially stretched polyethylene terephthalate film, an Ag metal thin film layer is formed to a thickness of 10 nm on this treated surface by sputtering. Formed to be.

Instead of using the substrate film of Example 1, a white film made of Teijin DuPont film (thickness 50 μm, U2 type, additive type) having a thickness of 50 μm was used. A window pasting film was obtained.

(Comparative Example 1)
Instead of using the base film of Example 1, a biaxially stretched polyethylene terephthalate film (thickness 50 μm, A4100) manufactured by Toyobo was used, and the film for window pasting of Comparative Example 1 was obtained in the same manner as Example 1 except that. It was.

(Comparative Example 2)
Instead of using the substrate film of Example 1, a biaxially stretched polyethylene terephthalate film (thickness 50 μm, A4100) manufactured by Toyobo was used, and the window pasting film of Comparative Example 2 was obtained in the same manner as in Example 3 except that. It was.

About the film for window sticking obtained in said Examples 1-4 and Comparative Examples 1 and 2, the total light transmittance, haze, perpendicular | vertical reflectance, and the near-infrared reflectance were measured, respectively.
(I) Total light transmittance The obtained window pasting film was measured for the total light transmittance using a double beam type haze computer (MODEL HGM-2B, Suga Test Instruments Co., Ltd., JIS-K-7105). .
(B) Haze Using the same equipment as in (a), haze was measured for the obtained window pasting film.
(C) Vertical reflectance
Using the spectrophotometer (Ubest series V-570 type, JASCO Corporation), the obtained window pasting film was measured for vertical reflectance at wavelengths of 400 nm to 800 nm. And the average value of the value for every 2 nm was taken.
(D) Near-infrared reflectance The obtained window pasting film was measured for vertical reflectance at a wavelength of 800 nm to 2500 nm using the same equipment as in (c). And the average value of the value for every 2 nm was taken.

In Examples 1 to 4, since the vertical reflectance is reduced as compared with Comparative Examples 1 and 2, it can be considered that the reflected light is diffused and the glare phenomenon is suppressed. Since Example 1 and Comparative Example 1, Example 3 and Comparative Example 2 are the same except that the base film is different, this difference is obvious.

  Compared to Example 3, Examples 1 and 2 have higher total light transmittance. Therefore, it can be said that by combining the metal thin film layer and the dielectric layer, the total light transmittance is increased and the transparency is excellent.

When Examples 1 and 4 are compared, it can be said that the sand matte film is superior to the white film in terms of diffusing reflection because the haze is higher and the vertical reflectance is lower.

The present invention is a window pasting film mainly used for window glass of vehicles such as automobiles, buildings, etc., which suppresses glare phenomenon due to light source and sunlight, improves comfortability, and also includes scattered light, A window pasting film having high visible light transmittance and high near infrared reflectance is provided.

It is a schematic sectional drawing which shows an example of embodiment of the film for window sticking of this invention.

Explanation of symbols

1, protective layer 2, dielectric layer 2
3, metal thin film layer 4, dielectric layer 1
5, base film 6, adhesive layer

Claims (4)

A metal thin film layer is provided on at least one surface of the base film, the vertical reflectance at a wavelength of 400 nm to 800 nm is 30% or less, the total light transmittance is 20% or more, and the haze is 50%. The film for window pasting characterized by the above-mentioned. 2. The window pasting film according to claim 1, wherein the vertical reflectance at a wavelength of 400 nm to 800 nm is 10% or less, and the vertical reflectance at a wavelength of 800 nm to 2500 nm is 50% or less. 3. The window pasting film according to claim 1, wherein the base film is a plastic film that has been subjected to sandblasting on the surface on which the metal thin film layer is provided. 4. The window pasting film according to claim 1, wherein a metal thin film layer and a dielectric layer are provided on at least one surface of the base film.

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