JPH058346A - Heat-resistant moistureproof film - Google Patents

Abstract

PURPOSE:To provide a heat-resistant and moistureproof film consisting of a laminated plastic film with excellent transparency and moistureproof characteristics. CONSTITUTION:This film consisting of each layer defined as described in (a)-(c) and wherein the second layer is bonded on one face of the first layer and the third layer is bonded on another face of the first layer. (a) The first layer A consists of a monolayered body or a laminated body constituted of a base film consisting of PVA with a degree of saponification of 99mol% or higher and a transparent silicon oxide thin film (an SO thin film) formed on at least one face thereof. (b) The second layer 3 is constituted of a monolayered body or a laminated body of a film consisting of a transparent plastic except PVA and wherein on at least one face of at least one film, a transparent SO thin film 4 with a thickness of 100-5,000Angstrom is formed and at least one layer of a heat-resistant transparent film having the sum of the absolute values of heat shrinkage in the longitudinal and transverse directions of 1% or smaller when it is heated at 150 deg.C for 30min and a light transmission of 85% or higher is incorporated. (c) The third layer C consists of a heat-sealable resin layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant moisture-proof film, and more specifically, a heat-resistant moisture-proof film which is transparent and has high heat resistance, and which has a high moisture-proof property of hardly permeating gases such as water vapor. And moisture-proof film.
The heat-resistant and moisture-proof film of the present invention is constituted as a laminated plastic film and is suitable as a package film for an EL device for backlight of liquid crystal display.

[0002]

2. Description of the Related Art Liquid crystal display elements are widely used in various fields such as OA equipment, taking advantage of the greatest feature that they can be driven with low power consumption. On the other hand, an organic dispersion type electroluminescence element (hereinafter abbreviated as “EL element”) is useful as an inexpensive flat emission backlight (auxiliary light source) for a liquid crystal display element by taking advantage of its thinness and light weight. It is spreading.

The above EL device has ZnS: Mn, ZnS:
Since it contains a fluorescent substance such as Cu and its emission luminance is significantly impaired by moisture absorption, it is packaged and used in a transparent film having an excellent moisture-proof property. The package generally uses two moisture-proof films each having a heat-sealable sealant layer on one surface, and the EL element sandwiched between the sealant layers of these two moisture-proof films. It is carried out by a method of passing a sealant layer around the entire periphery of the EL element by heat sealing by passing the sealant layer between upper and lower heating rolls with an appropriate nip pressure.

Conventionally, a laminated film mainly composed of a fluorinated resin film, particularly polychlorinated trifluoroethylene (hereinafter abbreviated as "PCTFE") has been used for an EL device package because of its excellent moisture-proof property and transparency. It is recommended because it has sex. The above laminated film is generally a PCTFE film having a thickness of about 70 to 300 μm and a thickness of 20 to 100 μ as a sealant for heat sealing.
It is said that it has the highest moisture-proof property among existing transparent plastic films because it is formed by laminating about m polyolefins and it is difficult for water vapor to pass through. Further, recently, a transparent laminated plastic film in which a metal oxide, in particular, a silicon or aluminum-based transparent oxide thin film is provided on the surface of a transparent plastic substrate film has been commercialized as a gas barrier packaging material. .

[0005]

However, the PCT
Since the laminated film mainly composed of FE is extremely expensive, there is a problem that the manufacturing cost of the backlight becomes high. In addition, the above laminated film has a problem that the moisture resistance of the laminated film deteriorates when the temperature of the atmosphere exceeds 50 ° C., so that the life of the EL element at high temperature becomes extremely short. Further, since the transparent laminated plastic film having a transparent thin film of a metal oxide on the surface is not sufficiently moisture-proof as it is, it cannot be used as a package film for an EL device. In addition, according to the knowledge of the present inventors, in the EL element sealing step, the package film is treated with a heating roll of about 110 to 150 ° C. Has a problem that the moisture-proof performance of the package film is impaired.

For the above reasons, it has been desired to develop a transparent plastic film that can be suitably used as a packaging film for EL devices, is cheaper than a PCTFE film, and is excellent in moistureproof performance. The present invention has been made in view of the above circumstances, and an object thereof is to have excellent transparency and moisture resistance, and a heat resistance comprising a laminated plastic film excellent in terms of strength, heat resistance and economical efficiency. To provide a moisture-proof moisture-proof film.

[0007]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have obtained the following findings. (1) A film in which a silicon oxide thin film is formed on the surface of a base film made of a specific polyvinyl alcohol has excellent transparency and moisture resistance, and other transparent films having a silicon oxide thin film formed on the surface are transparent. By being protected by the plastic film, stable moistureproof performance can be maintained for a long period of time even in a high temperature and high humidity atmosphere. (2) As the other transparent plastic film described above,
By including the film having the specific physical properties, the original gas barrier performance can be maintained even if it is subjected to heat and pressure in the EL element sealing step, and the deterioration of the moisture proof performance can be effectively prevented.

The present invention has been completed on the basis of the above findings, and the gist thereof is from the first layer (A), the second layer (B) and the third layer (C) defined as follows. Consists, first
The heat-resistant moisture-proof film is characterized in that the second layer is bonded to one surface of the layer and the third layer is bonded to the other surface of the first layer. (A) The first layer (A) is a single layer of a transparent laminated film composed of a base film made of polyvinyl alcohol having a saponification degree of 99 mol% or more and a transparent silicon oxide thin film formed on at least one surface thereof. It consists of a body or a laminate. (B) The second layer (B) is composed of a single layer or a laminate of films made of a transparent plastic other than polyvinyl alcohol, and at least one layer of the film has 100 to 5000 Å of transparent silicon oxide on at least one side. A thin film was formed, and the sum of the absolute values of the heat shrinkage ratios in the vertical and horizontal directions when heated at 150 ° C. for 30 minutes was 1% or less, and the light transmittance by ASTM D-1003 was 85%.
% Or more of at least one heat-resistant transparent film is included. (C) The third layer (C) is composed of a heat-sealable resin layer.

The present invention will be described in detail below. The heat-resistant moisture-proof film of the present invention comprises the first layer (A), the second layer (B) and the third layer (C) defined as above,
The second layer (B) is bonded to one surface of the layer (A), and the third layer (C) is bonded to the other surface.

First, the above layers will be sequentially described. (1) First Layer (A) In the heat-resistant moisture-proof film according to the present invention, the first layer (A) is made of polyvinyl alcohol having a saponification degree of 99 mol% or more (hereinafter abbreviated as “PVA”). It comprises a single layer body or a layered body of a transparent laminated film composed of a base film and a transparent silicon oxide thin film (hereinafter abbreviated as “SO thin film”) formed on at least one surface thereof.

The substrate PVA film has a saponification degree of 99.
It must consist of PVA in excess of mol%. 9
With a film made of PVA having a saponification degree of less than 9 mol%, excellent moistureproof performance cannot be obtained even if an SO thin film is formed on the surface of this film. The PVA film may be either an unstretched film or a stretched film, but from the viewpoint of film strength and moistureproof performance, a stretched film, particularly a biaxially stretched film stretched about 3 × 3 times is preferable. Further, the thickness can be selected in the range of 5 to 400 μm, and 10
It is preferable to select in the range of up to 200 μm.

The SO thin film formed on the surface of the PVA film may be formed on only one side or both sides of the film, but in order to maintain a high degree of moisture-proof performance for a long period of time, it is rather a protective layer. It is better to form the second layer (B) functioning as the above only on the surface to be laminated. The formation of SO thin film
Silicon monoxide, silicon dioxide, a mixture thereof, or the like can be used as a vapor deposition raw material, and the vapor deposition method, the sputtering method, or the ion plating method can be used. In addition to the above, a reactive vapor deposition method in which silicon, silicon monoxide, silicon dioxide, a mixture thereof, or the like is used as a vapor deposition raw material and oxygen gas is supplied can also be employed.

Prior to the formation of the SO thin film, it is possible to use an anchor coating agent in order to increase the adhesive strength between the thin film and the base film. Suitable anchor coat agents include isocyanate-based, polyethyleneimine-based and organic titanium-based adhesion promoters, and polyurethane and polyester-based adhesives. As the anchor coating agent, a polyethylene-based, polyester-based, or polyamide-based solventless adhesive may be used.

If the SO thin film is 10% by weight or less, even if calcium, magnesium, or an oxide thereof is mixed as an impurity in the thin film, the intended moisture-proof performance is not significantly reduced. . The thickness of SO thin film is 10
It is good to select in the range of 0 to 5000Å. If the thickness of the SO thin film is less than 100Å, the moisture-proof property is insufficient, and if it exceeds 5000Å, curling occurs in the film, which is a problem, and cracks or peeling easily occur in the SO thin film, which is preferable. Absent.

The above-mentioned first layer (A) is a single layer body composed of one transparent laminated film having a transparent SO thin film on one surface of the above-mentioned PVA base film, or a transparent laminated film composed of two or more transparent laminated films. It may be any of the laminates bonded by using the agent. Examples of adhesives that can be used when joining the single-layer bodies include urethane-based, acrylic-based, and polyester-based adhesives.

(2) Second Layer (B) In the present invention, the second layer (B) is bonded to one surface of the first layer (A), preferably the surface on the SO thin film side. The second layer (B) functions as a protective layer and is composed of a single layer or a laminate of films made of a transparent plastic other than PVA. Further, the second layer (B) has 100 at least on one side of the film of at least one layer constituting the second layer (B).
A transparent SO thin film having a thickness of up to 5000 Å is formed. Moreover, the second layer (B) includes at least one heat resistant transparent film.

In the present invention, the heat-resistant transparent film means that the sum of the absolute values of the heat shrinkage percentages in the machine direction and the transverse direction when heated at 150 ° C. for 30 minutes is 1% or less.
A film having a light transmittance of D-1003 (hereinafter, simply referred to as light transmittance) of 85% or more. In addition, the said heat shrinkage rate means the measured value after heating in the hot air oven controlled to 150 degreeC.

The transparent plastic film other than PVA is not particularly limited, and examples thereof include a film made of polyethylene terephthalate, polyacetate, polypropylene or polyamide. Moreover, the heat resistant transparent film described below can also be used. In particular, P
As a transparent plastic film other than VA, a biaxially stretched film of polyethylene terephthalate is suitable. On the other hand, the heat-resistant transparent film used for the second layer (B) is not particularly limited in its raw material resin as long as it has the above-mentioned characteristics, but a polysulfone-based resin, a polyarylate-based resin, a polyimide-based resin or the like described below is used. Each film used as a raw material is mentioned.

From the viewpoint of heat resistance, the above polysulfone resin has a sulfone bond and an ether bond in the main chain, and the following chemical formula [Chemical formula 2] is provided between these bonds.
An aromatic polysulfone-based resin having an aromatic residue bonded thereto as exemplified in (a) to (d) therein is preferably used.

[0020]

[Chemical 2]

Specific examples of the aromatic polysulfone-based resin as described above include various kinds of repeating units represented by (1) to (10) in the following chemical formulas [Chemical formula 3] and [Chemical formula 4]. Resin can be illustrated.

[0022]

[Chemical 3]

[0023]

[Chemical 4]

In the above aromatic polysulfone-based resin, the film made of the resin having the repeating unit (1) and the film made of the resin having the repeating unit (2) are already commercially available and easily available. Can be preferably used for The degree of polymerization (n) in the chemical formulas [Chemical Formula 3] and [Chemical Formula 4] is not particularly limited as long as it can be formed into a film, but in the resin having the repeating unit (1), 100 to 160, the repeating unit (2). The range of 50 to 80 for the resin having).

The above polyarylate resin is 2
A polycondensation product of a polyhydric phenol and an aromatic dicarboxylic acid can be used. Specifically, in the following chemical formula [Chemical formula 5] (11)
Various resins having the repeating units represented by (16) to (16) can be exemplified. The abbreviation (BISA) in the chemical formula [Chemical Formula 5] represents the residue of bisphenol A.

[0026]

[Chemical 5]

Degree of polymerization (n) in the above chemical formula [Chemical formula 5]
Is not particularly limited as long as it can be formed into a film, but is 50 to 110 in the case of the resin having the repeating unit (11). A film made of a polyarylate resin having a repeating unit (11) is already on the market and easily available, and thus can be preferably used.

As the above-mentioned polyimide resin, in addition to the narrowly defined polyimide resin having only an imide bond in the main chain,
A polyetherimide resin having an imide bond and an ether bond and a polyamideimide resin having an imide bond and an amide bond can be used. In such a polyimide resin, from the viewpoint of heat resistance, an aromatic residue in which an aromatic residue as exemplified by (e) to (g) in the following chemical formula [Chemical Formula 6] is bonded between the respective bonds. Group polyimide resins are preferably used.

[0029]

[Chemical 6]

As the above polyimide-based resin,
Specifically, (17) to (1
Various resins having the repeating unit represented by 9) can be exemplified. The resin having the repeating unit (17) is a polyimide resin, the resin having the repeating unit (18) is a polyetherimide resin, and the resin having the repeating unit (19) is a polyamideimide resin. Although there are colored polyimide resin films on the market,
In the present invention, any film having a light transmittance of 85% or more can be used.

[0031]

[Chemical 7]

In the present invention, among the above heat-resistant transparent films, a film made of a resin having a repeating unit (1), which is conventionally called a polyether sulfone resin, is most preferable. This is because a film made of a resin having a repeating unit (2) or a polyarylate-based resin, which is conventionally called a polysulfone resin, does not always have sufficient solvent resistance, and therefore, when the film is dry laminated as described later. The problem is that the surface of the film is easily corroded, but the film made of the polyether sulfone resin does not have such a problem at all.

The thickness of the transparent plastic film forming the second layer (B) is not particularly limited, but the thickness of the heat resistant transparent film is preferably selected from the range of 10 to 100 μm.

The heat-resistant moisture-proof film according to the present invention comprises the second
Excellent moisture proofing by including at least one heat-resistant transparent film in which the sum of the absolute values of heat shrinkage in the longitudinal direction and the transverse direction when heated at 150 ° C. for 30 minutes in the layer (B) is 1% or less. Although the performance is exhibited, it is presumed that this is based on the following effects. That is, even when the second layer (B) is a laminated body, the heat shrinkage rate is low as a whole. As a result, when the EL element is heated in the sealing process, the SO thin film of the second layer (B) is not prevented from being cracked, and the first layer (A) of the base film bonded thereto is shrunk. Therefore, cracking of the SO thin film on the surface of the base film is effectively prevented. In addition, the heat-resistant moisture-proof film according to the present invention has a light transmittance of 85% or more in the above heat-resistant transparent film, so that the heat-resistant moisture-proof film can be used even when it is used by laminating it with another transparent plastic film. It is possible to secure better transparency as the layer (B),
It is possible to satisfactorily transmit the emitted light rays of the sealed EL element.

The second layer (B) is composed of a single layer body or a laminated body of the above-mentioned transparent plastic film. In the case of a single layer body, it is necessary to itself be composed of the heat resistant transparent film. is there. When used as a laminate, the heat resistant transparent film is preferably positioned as the outermost layer.
As the bonding adhesive for forming the laminated body, the above-mentioned urethane-based, acrylic-based, polyester-based adhesive or the like can be used.

The second layer (B) is used as a transparent laminated film by forming an SO thin film on at least one surface of at least one layer of transparent plastic film constituting the second layer (B).
When the second layer (B) is a monolayer, it is necessary to form an SO thin film on itself (heat resistant transparent film) to form a transparent laminated film. The SO thin film can be formed by the above-described method of forming the SO thin film on the surface of the PVA film, and the thickness thereof needs to be in the range of 100 to 5000Å. If the thickness of the SO thin film is less than 100Å, the moisture-proof performance is insufficient, and if it exceeds 5000Å, curling occurs in the film, which causes a problem.
The thin film itself is easily cracked or peeled.

The second layer (B) is preferably bonded to the first layer (A) so that the heat-resistant transparent film is exposed on the outer surface. Due to such a layer structure, the SO thin film itself is scratched or scratched. It can be protected from being crushed, and as a result, the problem of deterioration of the moisture-proof performance which may be caused by breakage of the SO thin film is eliminated.

(3) Third Layer (C) In the present invention, the third layer (C) is bonded to the other surface of the first layer (A), preferably the PVA film side surface. The third layer (C) functions as a sealant and is made of a heat-sealable resin layer.

As the heat-sealable resin, general resins such as low density polyethylene, ethylene-vinyl acetate copolymer, polypropylene, ethylene-acrylate copolymer (ionomer) can be used. For applications requiring high moisture resistance such as package films for EL devices, ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate are used to prevent moisture permeation from the sealing surface. Copolymers (EEA) are preferred.

Next, a laminated structure in which the above layers are joined will be described. When the second layer (B) and the third layer (C) are bonded to the surface of the first layer (A), a dry laminating method or extrusion using a urethane adhesive, an acrylic adhesive, a polyester adhesive, or the like. A known method such as a laminating method can be adopted. When a film is joined as the third layer (C), this film may be an unstretched film or a uniaxially or biaxially stretched film. The stacking order of the third layer (C) may be before or after the formation of the SO thin film of the first layer (A).
In addition to the above, the third layer (C) is the first layer without using an adhesive.
For the layer (A), preferably for the PVA film surface,
It can also be provided by extrusion coating.

The heat-resistant and moisture-proof film of the present invention is particularly preferably used as a packaging film for EL devices.
Of course, it can also be suitably used as a package film for other packaged items that require moisture proofing. And, depending on the contents to be packaged, it is necessary to have an ultraviolet ray blocking ability in addition to the moistureproofing ability as the performance of the moistureproof film, but in the heat resistant moistureproof film according to the present invention, it is possible to impart the ultraviolet ray blocking performance as needed. is there. For example, a moisture-proof film having an ultraviolet blocking ability can be obtained by adding a substance having an ultraviolet absorbing ability to the adhesive layer at the time of joining the above layers.

As the ultraviolet absorber, one or a combination of commercially available products such as benzophenone and benzotriazole may be used, and the amount of the ultraviolet absorber used is determined by the required ultraviolet absorbing ability. Needless to say, the ultraviolet blocking ability can be imparted also by using a film containing a substance having an ultraviolet absorbing ability as a film forming each of the above layers.

In the moisture-proof film according to the present invention, the total thickness of the second layer (B) and the third layer (C) is 50-100.
The range of 0 μm is preferable, and the total thickness is preferably 100 to 1100 μm, more preferably 150 to 300 μm, from the viewpoint of strength, flexibility, economy and the like. Thickness ratio of each layer excluding the adhesive layer (A) :( B):
(C) is preferably 1: 1 to 10: 1 to 10. In addition, between the first layer (A) and the second layer (B), or between the first layer (A) and the third layer (C), a transparent plastic for adjusting the total thickness. It is also possible to interpose a film. The plastic film to be interposed is not particularly limited as long as it is transparent, but the same kind as the plastic film forming the second layer (B) is preferably used. The thickness of the plastic film to be interposed is selected in relation to the thickness of the entire moisture-proof film.

Next, specific examples of the layer structure of the moisture-proof film according to the present invention will be described. 1 to 5 are schematic cross-sectional views showing specific structural examples of the heat-resistant and moisture-proof film of the present invention.
In the following description, “SO thin film” means transparent SO.
It means a thin film, and "film" means the heat-resistant transparent film defined in the present invention, unless otherwise specified.

FIG. 1 shows the basic structure of the heat-resistant and moisture-proof film according to the present invention. The first layer (A) is PV
It is composed of a single layer of a transparent laminated film in which the SO thin film (2) is formed on one surface of the A film (1). Then, on the SO thin film (2) side, the SO thin film (4) is provided on one side of the film (3).
The second layer (B) consisting of a single layer body of the transparent laminated film on which is formed the adhesive layer (a) with the SO thin film (4) inside.
And a third layer (C) made of a heat-sealable resin is bonded to the PVA film side (1) of the first layer (A) via the adhesive layer (a). Has become.

FIG. 2 shows another structural example. In the structural example of FIG. 1, a laminated structure containing two films is used as the second layer (B). That is, in the second layer (B) in FIG. 2, the SO thin film (6) is formed on one side of the film (5) on the film side of the transparent laminated film having the SO thin film (4) formed on one side of the film (3). The transparent laminated film formed with is bonded to the SO thin film (6) with the adhesive layer (a) inside. Then, the second layer (B) composed of this laminated structure is bonded to the SO thin film (2) side of the first layer (A) with the SO thin film (4) inside and the adhesive layer (a). ing. In the structure example of FIG. 2, the film (3) may be a transparent plastic film other than the heat-resistant transparent film specified in the present invention.

FIG. 3 shows still another structural example, which is an example in which a laminated structure including two films is used as the second layer (B) as in the structural example of FIG. The difference from No. 2 is that only one SO thin film is formed in the second layer (B). That is, in the second layer (B) in FIG. 3, a film having no SO thin film formed on the SO thin film (4) side of the transparent laminated film having the SO thin film (4) formed on one surface of the film (3). (5) is the adhesive layer (a)
Are joined through. The second layer (B) composed of this laminated structure is bonded to the SO thin film (2) side of the first layer (A) with the film (3) inside and the adhesive layer (a). There is. In the structure example shown in FIG.
The film (3) may be a transparent plastic film other than the heat resistant transparent film specified in the present invention.

FIG. 4 shows still another structural example, which is an example in which a laminated structure is used as the second layer (B) similarly to the structural examples of FIGS. 2 and 3, but different from these. Another point is that a normal transparent plastic film not having high heat resistance is further added to form a laminated structure including three transparent plastic films. That is, in the second layer (B) in FIG. 4, the transparent laminated film having the SO thin film (4) formed on one surface of the film (3) has a normal transparent film having low heat resistance on the SO thin film (4) side. A transparent laminated film in which an SO thin film (6) is formed on one surface of a plastic film (5) is bonded via an adhesive layer (a) with the film (5) side facing inward, and the SO thin film (6) side, The film (7) on which the SO thin film is not formed is bonded via the adhesive layer (a). Then, the second layer (B) composed of this laminated structure is
The film (3) side is placed inside and is bonded to the SO thin film (2) side of the first layer (A) via the adhesive layer (a). In the structure example of FIG. 4, the film (3) is
A transparent plastic film other than the heat-resistant transparent film specified in the present invention may be used.

FIG. 5 shows still another structural example, which is an example in which a laminated structure is used as the first layer (A) in the structural example of FIG. That is, S is formed on one surface of the PVA film (1).
The two transparent laminated films having the O thin film (2) formed thereon are bonded to each other through the adhesive layer (a) to form a laminated structure, and the SO thin film (2) of the first layer (A) including the laminated structure is formed. ) Side,
Second layer (B) consisting of three-layer structure in the structural example of FIG.
However, the structure is such that the film (3) is placed inside and is bonded via the adhesive layer (a).

In the heat-resistant moisture-proof film according to the present invention, the moisture-proof property of its basic function is that the PVA of the first layer (A) is
It is realized by protecting the SO thin film formed on the film surface with the second layer (B). And it is presumed that the above excellent moisture resistance is exhibited based on the following actions. Generally, S formed on the surface of PVA film
The binding energy of silicon of the O thin film shows a peculiar value in the thickness direction of the thin film, and has a larger energy in the vicinity of the film than in the surface layer portion and the central portion, and the PVA film on which such an SO thin film is formed is at room temperature. Has excellent moisture resistance.

However, in a high-temperature and high-humidity atmosphere, the PVA film absorbs moisture and causes a dimensional change, which destroys the SO thin film on the surface and impairs the moisture resistance of the corners. The above problem may be solved by protecting the PVA film with a film. However, in a normal film, a PVDC film, a film coated with PVDC, or the like, the moisture-proof performance at high humidity is significantly deteriorated.
At 0 ° C or higher, almost no moisture absorption preventing effect of the PVA film can be expected. On the other hand, in the transparent laminated film having an SO thin film used as the second layer (B) in the present invention, the deterioration of the moisture-proof performance in the high temperature region is very small, so that the transparent layered film of the first layer (A) is used even in the high temperature region. It is considered that the transparent film is effectively protected and the excellent moisture resistance of the PVA film having the SO thin film formed thereon can be maintained even in a high temperature region.

The heat-resistant moisture-proof film according to the present invention has a sum of absolute values of heat shrinkage in the longitudinal direction and the transverse direction of 1% or less when heated in the second layer (B) at 150 ° C. for 30 minutes. Since the heat-resistant transparent film of (1) is included, for example, when the EL element is sealed, the SO thin film of the second layer (B) is not cracked, and the base film of the first layer (A) bonded thereto is shrunk. It is considered that the occurrence of cracking is suppressed and the occurrence of cracks in the SO thin film on the surface of the base film is effectively prevented. Therefore, the heat-resistant and moisture-proof film according to the present invention can be sufficiently used as a package film for EL devices that can be used not only for backlight applications of liquid crystal displays but also for automobiles and lighting applications.

[0053]

EXAMPLES Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.
The present invention will be described in more detail, but the present invention is not limited to the following examples unless it exceeds the gist. In addition,
In the following examples, each physical property value is measured by the following methods. (1) Thickness of SO thin film The thickness was measured by a crystal type film thickness meter when the thin film was formed. (2) Heat Shrinkage (%) The film was heated in a hot air oven at 150 ° C. for 30 minutes, and was determined from the rate of change in vertical and horizontal dimensions before and after heating.

(3) Water vapor transmission rate (gr / m ² · 24H) A 70 × 70 mm 3-sided seal (seal width 5 mm) bag was prepared from a predetermined moisture-proof film, and an EL element was substituted in the bag. As for, put cardboard in a highly hygroscopic and absolutely dry state,
The remaining one side was sealed by passing between two heated rubber rolls to prepare a cardboard sample. The sealing conditions were a heating temperature of 150 ° C. and a roll pressure of 10 Kg / cm. 10 samples each of the above cardboard enclosed samples at 50 ° C x 90%
The sample was allowed to stand in an atmosphere of RH for about 500 hours, and the moisture permeability of the moisture-proof film was determined from the weight change of the whole. (4) Transparency (%) The light transmittance of the film in visible light was measured using a spectrophotometer manufactured by Hitachi Ltd., and the light transmittance at 550 nm was defined as the transparency of the film.

Example 1 The films used in this example are as follows. <Laminate film (A)> PV having a saponification degree of 99.9 mol%
A biaxially stretched film of A (stretching ratio 3 × 3 times, thickness 12 μm) was used as a base film, and one surface thereof was provided with 5
X10-5 torr under vacuum, electron beam heating method,
A transparent SO thin film with a thickness of 1000Å formed by heating and evaporating silicon monoxide (SiO) with a purity of 99.9%.

<Laminated film (B)> The following laminated films (B-1) and ((B-1) were used in combination: (1) Laminated film (B-1) Polyethylene terephthalate (hereinafter referred to as "PET") And a biaxially stretched film (drawing ratio 3 × 3 times,
Prepared two sheets with a thickness of 1000 Å SO thin film formed on one side of 12 μm thickness by the same method as above.
One SO thin film surface and the other non-SO thin film surface are joined with a urethane adhesive. (2) Heat-resistant film (B-2) An unstretched film having a thickness of 50 μm made of a polyether sulfone resin, and the shrinkage ratio after heating at 150 ° C. for 30 minutes is 0. 10%, lateral direction (T
D) is 0.09% and the light transmittance is 88%.

<Sealant film> 50 μm thick made of ethylene-ethyl acrylate copolymer (EEA)
Unstretched film.

First, the SO thin film surface of the laminated film (A) and the non-SO thin film surface of the laminated film (B-1) are joined using a urethane adhesive (hereinafter simply referred to as "adhesive"). Then, the laminated film (B
The SO thin film surface of -1) and the heat resistant film (B-2) were bonded together using an adhesive to obtain a laminated film having a four-layer structure.

The sealant film (C) is bonded to the laminated film (A) side of the laminated film having the four-layer structure using an adhesive to form a transparent laminated film having the five-layer structure as shown in FIG. Obtained. Regarding the obtained laminated film,
As an alternative test of the EL element sealing step, the water vapor transmission rate was measured by the method described above. In addition, the transparency was measured by the method described above. The results are shown in Tables 1 to 3 together with the structure of the laminated film. In Table 2, the laminated film (B-
The meaning of each symbol in 2) is as follows. PES: A film made of a polyether sulfone resin having a repeating unit represented by (1) in the above chemical formula [Chemical Formula 3] [Mitsui Toatsu Chemical Co., Ltd., trade name TALPA]
-1000 (Tg: 225 ° C.) PSF: a film made of a polysulfone resin having a repeating unit represented by (2) in the chemical formula [Chemical Formula 3] [Sumilite FS, manufactured by Sumitomo Bakelite Co., Ltd.]
-1300 (Tg: 223 ° C.) PAr: A film made of a polyarylate resin having a repeating unit represented by (11) in the chemical formula [Chemical Formula 5] [manufactured by Sumitomo Chemical Co., Ltd., trade name ESPECS-R]. (T
g: 193 ° C.) PI: A film made of a polyimide resin having a repeating unit represented by (17) in the above chemical formula [Chemical Formula 7] PET: Polyethylene terephthalate film

Examples 2 to 7 and Comparative Examples 1 to 5 As described in Table 1, various laminated films were obtained in the same manner as in Example 1 except that the structure of the laminated film was changed.
Tables 1 to 3 show the configurations of the obtained laminated films and the measurement results of the respective physical properties. The sealant film in each laminated film is the same as that in Example 1, and the description is omitted in Table 1. As is clear from the results shown in Tables 1 to 3, a heat-resistant moisture-proof film having improved moisture permeability and transparency was obtained by including a predetermined heat-resistant transparent film in the second layer (B). can get.

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

[Table 3]

[0064]

The heat-resistant moisture-proof film according to the present invention has excellent transparency and extremely excellent moisture-proof property. It is also flexible and excellent in strength and economy. Moreover, even if it is used for a long time under severe conditions, the moisture-proof performance is not impaired. Therefore, it is suitable for applications requiring a high degree of moisture resistance such as package films for backline EL elements of liquid crystal displays that are used for a long time under severe conditions, and its industrial value is extremely large. is there.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a specific structural example of a heat-resistant moisture-proof film according to the present invention.

FIG. 2 is a cross-sectional view showing a specific structural example of a heat-resistant moisture-proof film according to the present invention.

FIG. 3 is a cross-sectional view showing a specific structural example of the heat-resistant moisture-proof film according to the present invention.

FIG. 4 is a cross-sectional view showing a specific structural example of the heat-resistant moisture-proof film according to the present invention.

FIG. 5 is a cross-sectional view showing a specific structural example of the heat-resistant moisture-proof film according to the present invention.

[Explanation of symbols]

(A): First layer (B): Second layer (C): Third layer (A): Adhesive layer (1): Polyvinyl alcohol film (2), (4), (6): Silicon oxide thin film (3), (5), (7): transparent film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C23C 14/10 8414-4K H05B 33/04 8815-3K

Claims (5)

[Claims] 1. A first layer (A), defined as follows:
It is composed of a second layer (B) and a third layer (C), characterized in that the second layer is joined to one surface of the first layer and the third layer is joined to the other surface of the first layer. A heat-resistant moisture-proof film that (A) The first layer (A) is a single layer of a transparent laminated film composed of a base film made of polyvinyl alcohol having a saponification degree of 99 mol% or more and a transparent silicon oxide thin film formed on at least one surface thereof. It consists of a body or a laminate. (B) The second layer (B) is composed of a single layer or a laminate of films made of a transparent plastic other than polyvinyl alcohol, and at least one layer of the film has 100 to 5000 Å of transparent silicon oxide on at least one side. A thin film was formed, and the sum of the absolute values of the heat shrinkage ratios in the vertical and horizontal directions when heated at 150 ° C. for 30 minutes was 1% or less, and the light transmittance by ASTM D-1003 was 85%.
% Or more of at least one heat-resistant transparent film is included. (C) The third layer (C) is composed of a heat-sealable resin layer. 2. The heat-resistant transparent film has a thickness of 10 to 1
The heat-resistant and moisture-proof film according to claim 1, wherein the heat-resistant and moisture-proof film is in a range of 00 μm. 3. The heat resistant transparent film according to claim 1, wherein the heat resistant transparent film is a film made of a polyether sulfone resin having a repeating unit represented by the following chemical formula [Chemical formula 1]. Moisture-proof film. [Chemical 1] 4. The silicon oxide thin film is formed by any one of a vacuum vapor deposition method, a sputtering method and an ion plating method, according to claim 1. Heat-resistant moisture-proof film. 5. The thickness of each of the base film and the silicon oxide thin film in the first layer (A) is 5 to 400 μm.
m is in the range of 100 to 5000Å, and the total thickness of the second layer (B) and the third layer (C) is in the range of 50 to 1000 μm. The heat-resistant moisture-proof film according to.