JPH04239634A - Weather-resistant transparent laminated film - Google Patents

Abstract

PURPOSE:To provide a heat-sealable transparent laminated film having excellent weatherability and moisture resistance. CONSTITUTION:A transparent silicon oxide membrane layer 2 with thickness of 100-5000Angstrom is arranged between a transparent fluoroplastic layer 1 and a heat-sealable transparent resin layer 3 in such a state that a transparent adhesive layer 4 is interposed between both resin layers 1, 3 to laminate all of the layers. An ultraviolet absorber is added to one or more layer among the transparent fluoroplastic resin layer 1, the heat-sealable transparent resin layer 3 and the transparent adhesive layer 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weather-resistant transparent laminate film, and more particularly to a weather-resistant transparent laminate film that is moisture-proof and heat-sealable.

0002

BACKGROUND OF THE INVENTION Many industrial components require protection from ultraviolet light and moisture without compromising transparency. For example, solar cells use single crystal silicon or amorphous silicon sealed with a glass plate. In order to reduce weight and prevent damage, sealing methods using plastic films have been studied, and the use of a laminated film of fluorine-based film and aluminum foil has already been proposed as a sealing film for the back side of solar cells. has been done. However, the sealing film for the surface requires transparency, weather resistance, and moisture resistance.

[0003]Also, EL elements are used as planar light emitters with low power consumption for backlights and illumination of LCD displays, and recently, they have also begun to be used as emblems for passenger cars. However, E.L.
The problem with devices is that their luminance decreases in a relatively short period of time under hot and humid conditions or when exposed to ultraviolet rays outdoors. There is a strong desire for a transparent sealing film that has moisture-proof properties.

0004

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to provide a transparent laminated film that has excellent weather resistance and moisture resistance and is heat-sealable. Our goal is to provide the following.

[0005]

[Means for Solving the Problems] That is, the gist of the present invention is to provide a transparent silicon oxide thin film layer with a thickness of 100 to 5,000 Å between a fluorine-based transparent resin layer and a heat-sealable transparent resin layer. and, if desired, other transparent resin layers are laminated with a transparent adhesive layer interposed therebetween, and at least one layer other than the silicon oxide thin film layer is provided with an ultraviolet blocking function. transparent laminated film.

The present invention will be explained in detail below. First, the fluorine-based transparent resin layer will be explained. In the present invention, the fluorine-based transparent resin is polyvinyl fluoride (PV
F), polyvinylidene fluoride (PVDF), polychlorinated trifluoroethylene (PCTFE) or copolymers thereof or copolymers with tetrafluoroethylene (PFA, F)
A transparent fluororesin such as EP) is used. and,
The thickness of the fluorine-based transparent resin layer is not particularly limited, but is selected from the range of 10 to 300 μm for sealing solar cells and EL elements. Fluorine-based resins generally have a surface that is difficult to wet, making it difficult to laminate them with other films using an adhesive, but this can be done, for example, by plasma-treating the surface.

Next, the heat-sealable transparent resin layer will be explained. In the present invention, heat-sealable transparent resins include common transparent thermoplastic resins such as low-density polyethylene, ethylene-vinyl acetate copolymer, polypropylene, and ethylene-acrylate copolymer (ionomer). can use things. In particular, solar cells and EL
For advanced moisture-proof applications such as device sealing, ethylene-acrylic acid copolymer (
EAA) and ethylene-ethyl acrylate (EEA) are preferred.

The heat-sealable transparent resin layer may be laminated as a film or may be formed by extrusion lamination. A heat-sealable transparent resin layer generally does not have very good moisture resistance, and if it is too thick, moisture will easily enter from the cross section of the layer. Therefore, the thickness of the heat-sealable transparent resin layer is preferably selected from a range of 100 μm or less.

Next, the transparent silicon oxide thin film layer will be explained. A transparent silicon oxide thin film layer (SO thin film layer) is provided so as to be located between the fluorine-based transparent resin layer and the heat-sealable transparent resin layer. Specifically, for example, an SO thin film layer is formed on the surface of a fluorine-based transparent resin layer,
A fluorine-based transparent resin layer and a heat-sealable transparent resin layer are laminated so that this layer is not located on the outer surface.

[0010] Furthermore, an SO thin film layer is formed on the surface of the other transparent resin layer other than the fluorine-based transparent resin layer and the heat-sealable transparent resin layer, and this is used as the fluorine-based transparent resin layer and the heat-sealable transparent resin layer. It may also be stacked and positioned between. As the other transparent resin layer, for example, a film of polyethylene terephthalate, polypropylene, polyethylene, nylon, polycarbonate, methyl methacrylate, etc. is used, and it may be an unstretched film, a uniaxially stretched film, or a biaxially stretched film. It's okay. In particular, biaxially oriented polyethylene terephthalate film is preferably used in terms of strength, cost, etc.

[0011] When using an SO thin film layer formed on the surface of another transparent resin layer, only one resin layer having the SO thin film layer may be used, but by using two or more layers, a more advanced and stable Provides moisture-proof performance.

[0012] The SO thin film layer provided between the fluorine-based transparent resin layer and the heat-sealable transparent resin layer is protected by each layer, so that it is not destroyed during heat-sealing and has high moisture-proof performance. can be demonstrated stably.

The SO thin film layer can be formed by any one of vacuum evaporation, sputtering, and ion plating using silicon monoxide, silicon dioxide, or a mixture thereof as a deposition raw material. In addition, a reactive vapor deposition method may be employed in which silicon, silicon monoxide, silicon dioxide, or a mixture thereof is used as a vapor deposition raw material and oxygen gas is supplied.

[0014] Prior to forming the SO thin film layer, it is also possible to use an anchor coating agent in order to increase the adhesive strength between the SO thin film layer and the film to be deposited. Suitable anchor coating agents include isocyanate-based, polyethyleneimine-based,
Mention may be made of adhesion promoters such as those based on organic titanium and adhesives such as those based on polyurethane polyesters. Also,
As the anchor coating agent, a polyethylene-based, polyester-based, or polyamide-based solvent-free adhesive may be used.

[0015] Furthermore, if the SO thin film layer contains impurities such as calcium, magnesium, or their oxides, if it is less than 10% by weight, there will be no significant decrease in the desired moisture-proofing performance. I can't.

[0016] The thickness of the SO thin film layer is between 100 and 5,000 mm.
It is necessary to keep it within the range of Å. The thickness of the SO thin film layer is 100
If it is less than Å, the moisture-proof performance is insufficient, and if it is less than 5,0
If it exceeds 00 Å, curling may occur in the deposited film, which may cause problems, or the SO thin film layer itself may easily crack or peel, which is not preferable.

Next, a method of laminating each of the above layers will be explained. To laminate a fluorine-based transparent resin layer, a heat-sealable transparent resin layer, and other transparent resin layers with an SO thin film layer on their surfaces, dry lamination is performed using a transparent adhesive such as urethane-based, acrylic-based, or polyester-based adhesive. The method is preferably used. In addition, for example, when laminating a heat-sealable transparent resin layer on the SO thin film layer side of a fluorine-based transparent resin layer having an SO thin film layer on the surface, extrusion lamination can be used without using a transparent adhesive. It can also be adopted. In this case, it is preferable to apply an anchor coating agent to the SO thin film layer side on which the heat-sealable transparent resin layer is laminated.

The transparent laminated film of the present invention is constructed as described above, but the overall thickness is preferably in the range of 30 to 1,100 μm from the viewpoint of strength, flexibility, economical efficiency, etc.
More preferably, it is in the range of 50 to 350μ.

Further, in the laminated film of the present invention, it is necessary that at least one layer other than the silicon oxide thin film layer has an ultraviolet blocking function. That is, although the fluorine-based transparent resin layer generally has excellent weather resistance itself and is less prone to discoloration and deterioration, only the lamination of the fluorine-based transparent resin layer is not sufficient to prevent the transmission of ultraviolet rays. Therefore, in the present invention, in order to protect the internal element to be sealed and each laminated layer from deterioration due to ultraviolet rays, one of a fluorine-based transparent resin layer, a heat-sealable transparent resin layer, and an adhesive layer is used. A UV absorber is added above the layer to provide UV blocking function.

The ultraviolet blocking function is preferably imparted to the fluorine-based transparent resin layer or to the layer that becomes the outer layer when used as a sealing film. The ultraviolet absorber to be used is not particularly limited, and commercially available ones such as benzophenone and benzotriazole can be used.

Next, a specific example of the layer structure of the transparent laminated film according to the present invention will be explained. 1 to 3 are schematic cross-sectional views showing examples of the layer structure of the transparent laminated film according to the present invention.

The transparent laminated film shown in FIG.
It has a two-layer structure in which a heat-sealable transparent resin layer (3) is laminated on the O thin film layer side via a transparent adhesive layer (4).

The transparent laminated film shown in FIG. 2 is different from the transparent laminated film shown in FIG. 1 in that it uses a transparent intermediate resin layer (5) having an SO thin film layer (2) on its surface. That is, the fluorine-based transparent resin layer (1) is laminated on the SO thin film layer side of the intermediate resin layer (5) via the transparent adhesive layer (4), and the transparent adhesive layer (4) is laminated on the non-SO thin film layer side of the intermediate resin layer (5). It has a three-layer structure in which a transparent resin layer (3) that can be heat-sealed is laminated with a heat-sealable resin layer (3) interposed therebetween.

The transparent laminated film shown in FIG. 3 is different from the transparent laminated film shown in FIG. 2 in that it uses transparent intermediate resin layers (5) and (6) having an SO thin film layer (2) on the surface. . That is, a fluorine-based transparent resin layer (
1) is laminated, and on the non-SO thin film layer side of the intermediate resin layer (6),
A heat-sealable transparent resin layer (3) is laminated via a transparent adhesive layer (4). It has a four-layer structure in which the SO thin film layer side of the intermediate resin layer (6) is laminated on the non-SO thin film layer side of the intermediate resin layer (5) via the transparent adhesive layer (4).

[0025]

[Examples] The present invention will be explained in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following Examples unless the gist thereof is exceeded. In addition, in the following examples, the methods for measuring the moisture permeability, transparency, and weather resistance of the obtained films are as follows, and the thickness of the SO thin film layer is the value measured using a quartz crystal film thickness meter. . In addition,
The structure and physical property measurement results of the laminated films obtained in the following examples are summarized in Tables 1 and 2.

(1) Moisture permeability (gr/m2 ・24H
) From the specified moisture-proof film, the inner dimensions are 100 x 100 mm.
Create a bag with three side seals (seal width 10mm), fill the bag with 300g of dried calcium chloride,
40 calcium chloride filling bags with one side sealed
The sample was left standing under the conditions of ℃ x 90% RH, and the weight increase over time was tracked, and the moisture permeability was determined from the number of days over time and the slope of the weight increase.

(2) Transparency The total light transmittance of the film before being subjected to the weather resistance test was measured using a color difference meter 1001DP manufactured by Nippon Denshoku Industries, and the transparency of the film was determined.

(3) After irradiating the surface of the weather-resistant fluororesin layer with 5000 HR ultraviolet rays using a Sunshine Weatherometer manufactured by Suga Test Instruments, the total light transmittance of the film was measured using a color difference system 100 manufactured by Nippon Denshoku Industries.
It was measured at 1DP, and the rate of decrease from the total light transmittance before UV irradiation was defined as weather resistance.

Example 1 Transparent polyvinyl fluoride (PVF) having ultraviolet blocking ability
) film (Tedlar 100BG3 manufactured by DuPont Japan)
0UT, thickness 25μ), 5×105 Torr on one side.
Silicon monoxide (SiO) with a purity of 99.9% is heated and evaporated to a thickness of 1,000 Å using an electron beam heating method under vacuum.
A SO thin film layer was formed. Using urethane adhesive,
An unstretched film of ethylene ethyl acrylate having a thickness of 50 μm was laminated on the SO thin film layer of the above film to obtain a transparent laminated film (film configuration shown in FIG. 1).

Example 2 Transparent film of biaxially oriented polyethylene terephthalate (
In the same manner as in Example 1, an SO thin film layer of 1,000 Å thick was formed on one side of a PET film (thickness: 12 μm). Using a urethane adhesive, a PVF film of the same type as that used in Example 1 was laminated on the SO thin film layer side of the above film, and a non-SO
An EEA film of the same kind as that used in Example 1 was laminated on the thin film layer side to obtain a transparent laminated film (film configuration shown in FIG. 2).

Example 3 Transparent film of biaxially oriented polyethylene terephthalate (
In the same manner as in Example 1, an SO thin film layer of 1000 Å thick was formed on one side of a PET film (thickness: 12 μm). Using a urethane adhesive, a polychlorinated trifluoroethylene (PCTFE) film (Neoflon DF-0025, manufactured by Daikin Industries, Ltd., thickness 25μ) was laminated on the SO thin film layer side of the above film, and the Example was laminated on the non-SO thin film layer side. EEA of the same type as used in 1.
The films were laminated to obtain a transparent laminated film (film configuration shown in FIG. 2). In addition, 20 wt% of benzotriazole-based UV absorber was added to the urethane adhesive used for laminating each film based on the solid content of the adhesive (total amount of urethane adhesive and UV absorber). The film has UV blocking ability.

Example 4 Example 2 was repeated except that two PET films having an SO thin film layer were laminated between the PVF and the EEA.
A laminated film was obtained in the same manner as (film configuration shown in FIG. 3).

Example 5 A laminated film was obtained in the same manner as in Example 1, except that the thickness of the SO thin film layer was changed to 100 Å (film configuration shown in FIG. 1).

Example 6 A laminated film was obtained in the same manner as in Example 2, except that the thickness of the SO thin film layer was 100 Å (film configuration shown in FIG. 2).

Comparative Example 1 In Example 1, instead of the PVF film having ultraviolet blocking ability, a PVF film having no ultraviolet blocking ability (Tedlar 100BG30TR manufactured by DuPont Japan, thickness 2) was used.
A laminated film was obtained in the same manner as in Example 1, except that the SO thin film layer was not formed.

Comparative Example 2 In Example 1, a PVF film without ultraviolet blocking ability (same type as in Comparative Example 1) was used in place of the PVF film having ultraviolet blocking ability, and the thickness of the SO thin film layer was increased to 50 mm.
A laminated film was obtained in the same manner as in Example 1 except that the thickness was changed to .ANG. (film configuration shown in FIG. 1).

Comparative Example 3 In Example 2, a PVF film without ultraviolet blocking ability (same type as in Comparative Example 1) was used in place of the PVF film having ultraviolet blocking ability, and the thickness of the SO thin film layer was set to 50 mm.
A laminated film was obtained in the same manner as in Example 2, except that the thickness was changed to .ANG. (film configuration shown in FIG. 2).

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

Effects of the Invention According to the present invention as described above, a transparent laminated film having excellent weather resistance and moisture resistance and capable of being heat-sealed is provided. It is suitable as a protective film for solar cells and EL elements.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of a transparent laminated film according to the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of the layer structure of a transparent laminated film according to the present invention.

FIG. 3 is a schematic cross-sectional view showing an example of the layer structure of a transparent laminated film according to the present invention.

[Explanation of symbols]

1... Fluorine-based transparent resin layer 2... Transparent silicon oxide thin film layer 3... Heat-sealable transparent resin layer 4... Adhesive layer 5, 6...・Transparent intermediate resin layer

Claims (3)

[Claims] Claim 1: A transparent silicon oxide thin film layer with a thickness of 100 to 5,000 Å and, if desired, another transparent resin layer is required between the fluorine-based transparent resin layer and the heat-sealable transparent resin layer. 1. A weather-resistant transparent laminated film, which is laminated with a transparent adhesive layer interposed therebetween, and at least one layer other than the silicon oxide thin film layer is provided with an ultraviolet blocking function. 2. The weather-resistant transparent laminated film according to claim 1, wherein the silicon oxide thin film layer is formed on the surface of the fluorine-based transparent resin layer. 3. Claim 1, wherein the silicon oxide thin film layer is formed on the surface of another transparent resin layer located between the fluorine-based transparent resin layer and the heat-sealable transparent resin layer. The weather-resistant transparent laminated film described in .