JP3020692B2 - Heat resistant moisture proof film - Google Patents

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 particularly, to a heat-resistant moisture-proof film which is transparent, has high heat resistance, and has high moisture-proof performance which hardly transmits gas such as water vapor. The present invention relates to a moisture-proof film.
The heat-resistant moisture-proof film of the present invention is configured as a laminated plastic film, and is suitable as a package film for a backlight EL element of a liquid crystal display.

[0002]

2. Description of the Related Art Liquid crystal display elements are widely used in various fields such as office automation 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 used as an inexpensive planar light emitting backlight (auxiliary light source) for a liquid crystal display element by utilizing its thin and lightweight features. Is spreading.

[0003] The above-mentioned EL element is composed of ZnS: Mn, ZnS:
Since it contains a fluorescent substance such as Cu and its emission luminance is significantly impaired by moisture absorption, it is used by being packaged with a transparent film having excellent moisture-proof performance. The package generally uses two moisture-proof films each having a heat-sealable sealant layer on one surface, and an EL element sandwiched between the sealant layers of the two moisture-proof films. This is carried out by a method in which the sealant layer is passed between heating rolls arranged above and below at an appropriate nip pressure and the sealant layer around the entire EL element is heat-sealed.

Conventionally, a fluorinated resin film, in particular, a laminated film mainly composed of polychlorinated ethylene trifluoride (hereinafter abbreviated as "PCTFE") has been used as a package for an EL element, because of its excellent moisture-proof performance and transparency. It is recommended because of its properties. The above laminated film is generally formed into a PCTFE film having a thickness of about 70 to 300 μm and a sealant for heat sealing having a thickness of 20 to 100 μm.
It is said that it has the best moisture-proof performance among existing transparent plastic films because it is formed by laminating about m polyolefins and hardly permeates water vapor. Further, recently, a transparent laminated plastic film in which a metal oxide, particularly 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]

SUMMARY OF THE INVENTION However, PCT
Since the laminated film mainly composed of FE is extremely expensive, there is a problem that the manufacturing cost of the backlight is increased. In addition, the above-mentioned laminated film has a problem that when the temperature of the atmosphere exceeds 50 ° C., the moisture-proof performance of the laminated film is deteriorated, so that the life of the EL element at a high temperature is extremely shortened. Further, a transparent laminated plastic film provided with a transparent thin film of a metal oxide on the surface has not yet been used as a package film for an EL element because the moisture-proof performance is not sufficient as it is. In addition, according to the findings of the present inventors, in the EL element sealing step, the package film is treated with a heating roll at about 110 to 150 ° C. However, there is a problem that the moisture-proof performance of the package film is impaired.

[0006] For the above reasons, there has been a demand for a transparent plastic film which can be suitably used as a package film for an EL element, is less expensive than a PCTFE film, and has excellent moisture proof performance. The present invention has been made in view of the above circumstances, and has as its object to provide a heat-resistant laminated plastic film having excellent transparency and moisture-proof properties, and excellent strength, heat resistance and economy. Another object of the present invention is to provide a moisture-proof film.

[0007]

Means for Solving the Problems The present inventors have earnestly studied to solve the above problems and have obtained the following findings. (1) A film in which a silicon oxide thin film is formed on the surface of a substrate film made of a specific polyvinyl alcohol has excellent transparency and moisture-proof properties, and other transparent films having a silicon oxide thin film formed on the surface. By being protected by the plastic film, stable moisture-proof performance can be maintained over a long period of time even under a high-temperature and humid atmosphere. (2) As another transparent plastic film described above,
By including a film having specific physical properties, the original gas barrier performance can be maintained even if the film is heated and pressurized in the EL element sealing step, and a decrease in moisture-proof performance can be effectively prevented.

[0008] The present invention has been completed based on the above findings, and the gist of the present invention is that the first layer (A), the second layer (B) and the third layer (C) defined as follows. First
The heat-resistant and moisture-proof film is characterized in that a second layer is bonded to one surface of the layer and a 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 degree of saponification of 99 mol% or more and a transparent silicon oxide thin film formed on at least one surface thereof. Consisting of a body or a laminate. (B) The second layer (B) is composed of a single layer or a laminate of a film made of a transparent plastic other than polyvinyl alcohol, and at least one side of at least one layer of the film has a transparent silicon oxide of 100 to 5000 °. A thin film was formed, and the sum of the absolute values of the heat shrinkage in the vertical and horizontal directions when heated at 150 ° C. for 30 minutes was 1% or less, and the light transmittance according to ASTM D-1003 was 85%.
% Or more of the heat-resistant transparent film. (C) The third layer (C) is composed of a heat sealable resin layer.

Hereinafter, the present invention will be described in detail. 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 joined to one surface of the layer (A), and the third layer (C) is joined to the other surface.

First, each of the above layers will be described sequentially. (1) First Layer (A) In the heat-resistant and 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 is a single layer or a laminate 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 PVA film as a substrate has a saponification degree of 99.
It is necessary to consist of PVA that is at least mol%. 9
With a film made of PVA having a degree of saponification of less than 9 mol%, even if an SO thin film is formed on the surface of the film, excellent moisture-proof performance cannot be obtained. The PVA film may be an unstretched film or a stretched film, but a stretched film, particularly a biaxially stretched film stretched about 3 × 3 times is preferable from the viewpoint of film strength and moisture-proof performance. The thickness can be selected in the range of 5 to 400 μm,
It is preferable to select in the range of -200 µm.

The SO thin film formed on the surface of the PVA film may be formed on only one side of the film or on both sides of the film. It is better to form the second layer (B) functioning as only on the surface to be laminated. The formation of SO thin film
Using silicon monoxide, silicon dioxide, a mixture thereof, or the like as a deposition material, the deposition can be performed by any one of a vacuum deposition method, a sputtering method, and an ion plating method. In addition, 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 while supplying oxygen gas can also be employed.

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

If the SO thin film is 10% by weight or less, even if calcium, magnesium or their oxides are mixed therein as impurities, no extreme decrease in the target moisture-proof performance is observed. . The thickness of the SO thin film is 10
It is good to choose in the range of 0-5000 °. When the thickness of the SO thin film is less than 100 mm, the moisture-proof performance is insufficient. When the thickness exceeds 5000 mm, curling occurs in the film, which causes a problem or the SO thin film itself is easily cracked or peeled. Absent.

The first layer (A) is a single-layer body composed of one transparent laminated film having a transparent SO thin film on one side of the above-mentioned base film made of PVA or two or more transparent laminated films. Any of the laminates joined using an agent may be used. Examples of adhesives that can be used when joining the single-layered 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 to the surface on the SO thin film side. The second layer (B) functions as a protective layer and consists of a single layer or a laminate of a film made of a transparent plastic other than PVA. Further, the second layer (B) has at least one surface of at least one layer of a film constituting the second layer (B).
A transparent SO thin film of ５5000 ° is formed. Moreover, the second layer (B) includes at least one layer of a heat-resistant transparent film.

In the present invention, the heat-resistant transparent film is defined as having a sum of absolute values of the heat shrinkage in the longitudinal and transverse directions when heated at 150 ° C. for 30 minutes of 1% or less.
A film having a light transmittance according to 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 a hot-air oven controlled at 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. Further, a 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 preferable. 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 or a polyimide-based resin described below is used. Each film used as a raw material is mentioned.

The above polysulfone resin has a sulfone bond and an ether bond in the main chain from the viewpoint of heat resistance, and the following chemical formula [Chemical Formula 2] between these bonds.
Aromatic polysulfone resins to which aromatic residues are bonded as exemplified in (a) to (d) are preferably used.

[0020]

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Specific examples of the aromatic polysulfone-based resin as described above include various types having a repeating unit represented by the following chemical formulas [Chemical Formula 3] and [Chemical Formula 4]. A resin can be exemplified.

[0022]

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[0023]

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In the above-mentioned aromatic polysulfone-based resin, a film made of a resin having a repeating unit (1) and a film made of a resin having a repeating unit (2) are already commercially available and easily available. It can be suitably 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 a film can be formed. ) Is in the range of 50 to 80.

As the polyarylate resin, 2
Polycondensates of polyhydric phenols and aromatic dicarboxylic acids can be used. Specifically, in the following chemical formula [Chemical Formula 5], (11)
Examples of various resins having a repeating unit represented by formulas (16) to (16) can be given. The abbreviation (BISA) in the chemical formula [Chemical Formula 5] represents a residue of bisphenol A.

[0026]

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The polymerization degree (n) in the above chemical formula [Formula 5]
Is not particularly limited as long as it can be formed into a film, but is in the range of 50 to 110 for the resin having the repeating unit (11). A film made of a polyarylate resin having the repeating unit (11) is already commercially available and is easily available, so that it can be suitably used.

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

[0029]

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As the polyimide resin as described above,
Specifically, (17) to (1) in the following chemical formula [Formula 7]
Examples of various resins having a repeating unit represented by 9) can be given. 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. In addition, 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]

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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 preferred. This is because a film made of a resin having a repeating unit (2) or a polyarylate resin, which is conventionally called a polysulfone resin, does not always have sufficient solvent resistance. However, there is a problem that the film surface is easily eroded, but the film made of the polyether sulfone resin has no such problem.

The thickness of the transparent plastic film constituting 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 and moisture-proof film according to the present invention comprises
Excellent moisture proof by including at least one heat-resistant transparent film in the layer (B) having a sum of absolute values of heat shrinkage in the vertical and horizontal directions of 1% or less when heated at 150 ° C. for 30 minutes. It performs well, but this is presumed to be based on the following effects. That is, even when the second layer (B) is a laminate, the heat shrinkage rate is low as a whole. As a result, when the EL element is heated in the sealing step, cracking of the SO thin film of the second layer (B) is not only prevented, but also the shrinkage of the base film of the first layer (A) joined thereto. , Cracks in the SO thin film on the surface of the base film are effectively prevented. Further, the heat-resistant moisture-proof film according to the present invention has a light transmittance of 85% or more, so that the heat-resistant transparent film has a second light-transmitting property even when used with another transparent plastic film. As layer (B), better transparency can be secured,
Light emitted from the sealed EL element can be transmitted well.

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

As the second layer (B), an SO thin film is formed on at least one surface of at least one layer of a transparent plastic film constituting the second layer (B), and is used as a transparent laminated film.
When the second layer (B) is a single-layer body, it is necessary to form an SO thin film on itself (heat-resistant transparent film) to form a transparent laminated film. The formation of the SO thin film can be performed by the above-described method of forming the SO thin film on the surface of the PVA film, and its thickness needs to be in the range of 100 to 5000 °. When the thickness of the SO thin film is less than 100 °, the moisture-proof performance is insufficient. When the thickness exceeds 5000 °, curling occurs in the film, causing a problem.
The thin film itself tends to crack or peel.

The second layer (B) is preferably bonded to the first layer (A) such that the heat-resistant transparent film is exposed on the outer surface. As a result, it is possible to protect from crushing, and as a result, there is no problem of deterioration of the moisture-proof performance, which may be caused by damage of the SO thin film.

(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 surface on the PVA film side. 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-proof performance, such as package films for EL devices, ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate, etc. are used to prevent moisture permeation from the sealing surface. Copolymer (EEA) is preferred.

Next, a laminated structure in which the above layers are joined will be described. When joining the second layer (B) and the third layer (C) to the first layer (A) surface, a dry lamination method using a urethane-based adhesive, an acrylic-based adhesive, a polyester-based adhesive, or the like is used. A known method such as a lamination method can be employed. When a film is bonded as the third layer (C), the film may be either an unstretched film or a uniaxially or biaxially stretched film. The order of lamination 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) uses 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 moisture-proof film of the present invention is particularly preferably used as a package film for an EL device.
Of course, it can also be suitably used as a package film for other packages requiring moisture proof. And, depending on the contents to be wrapped, the moisture-proof film requires ultraviolet shielding ability in addition to the moisture-proof performance as a performance of the moisture-proof film, but the heat-resistant moisture-proof film according to the present invention can impart the ultraviolet shielding ability as needed. is there. For example, a moisture-proof film having ultraviolet blocking ability can be obtained by adding a substance having ultraviolet absorbing ability to the adhesive layer at the time of bonding the above layers.

As the ultraviolet absorber, one or a combination of commercially available ultraviolet absorbers such as benzophenone and benzotriazole is used, and the amount of the ultraviolet absorber used is determined according to the required ultraviolet absorbing ability. It is needless to say that 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-mentioned 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 to 100.
The thickness is preferably in the range of 0 μm, and the total thickness is preferably in the range of 100 to 1100 μm, and more preferably in the range of 150 to 300 μm from the viewpoint of strength, flexibility, economy and the like. Ratio of thickness of each layer excluding the adhesive layer (A): (B):
(C) is preferably from 1: 1 to 10: 1 to 10. It should be noted that, between the first layer (A) and the second layer (B), or between the first layer (A) and the third layer (C), a transparent plastic is used to adjust the overall thickness. A film can be interposed. The plastic film to be interposed is not particularly limited as long as it is transparent, but the same type of plastic film as that forming the second layer (B) is preferably used. The thickness of the interposed plastic film 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 moisture-proof film of the present invention.
In the following description, “SO thin film” refers to transparent SO
The term “film” means a thin film, and unless otherwise specified, means a heat-resistant transparent film defined in the present invention.

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
The A film (1) is composed of a single layer of a transparent laminated film having an SO thin film (2) formed on one surface. Then, on one side of the film (3), on the SO thin film (2) side, an SO thin film (4)
The second layer (B) composed of a single layer of a transparent laminated film on which is formed an adhesive layer (a) with the SO thin film (4) inside.
And a third layer (C) made of a heat-sealable resin is joined to the first layer (A) on the PVA film side (1) via an adhesive layer (a). It has become.

FIG. 2 shows another example of the structure. In the example of the structure shown in FIG. 1, a laminated structure including two films is used as the second layer (B). That is, in the second layer (B) in FIG. 2, on the film side of the transparent laminated film having the SO thin film (4) formed on one surface of the film (3), the SO thin film (6) is formed on one surface of the film (5). Are bonded via the adhesive layer (a) with the SO thin film (6) inside. Then, the second layer (B) made of the laminated structure is joined to the first layer (A) side of the SO thin film (2) via the adhesive layer (a) with the SO thin film (4) inside. ing. In the structure example shown in FIG. 2, the film (3) may be a transparent plastic film other than the heat-resistant transparent film defined in the present invention.

FIG. 3 shows still another structural 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 the second layer 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 without an SO thin film is formed on the SO thin film (4) side of the transparent laminated film in which the SO thin film (4) is formed on one surface of the film (3). (5) The adhesive layer (a)
Are joined through. Then, the second layer (B) composed of the laminated structure is bonded to the first layer (A) side of the SO thin film (2) via the adhesive layer (a) with the film (3) inside. I have. In the structure example of FIG.
The film (3) may be a transparent plastic film other than the heat-resistant transparent film defined in the present invention.

FIG. 4 shows still another structural example, in which a laminated structure is used as the second layer (B), as in the structural examples of FIGS. 2 and 3, except for the differences. Another point is that a normal transparent plastic film having a low 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, a normal transparent film having low heat resistance is provided on the SO thin film (4) side of the transparent laminated film in which the SO thin film (4) is formed on one surface of the film (3). A transparent laminated film in which an SO thin film (6) is formed on one side of a plastic film (5) is joined via an adhesive layer (a) with the film (5) side inside, and on the SO thin film (6) side, The film (7) on which the SO thin film is not formed is joined via the adhesive layer (a). And the second layer (B) composed of this laminated structure is
The first layer (A) is bonded to the SO thin film (2) side via the adhesive layer (a) with the film (3) side inside. In the structure example of FIG. 4, the film (3) is
A transparent plastic film other than the heat-resistant transparent film defined in the present invention may be used.

FIG. 5 shows still another structural example, in which a laminated structure is used as the first layer (A) in the structural example of FIG. That is, on one side of the PVA film (1), S
The two transparent laminated films on which the O thin film (2) is formed are joined via an adhesive layer (a) to form a laminated structure, and the SO thin film (2) of the first layer (A) made of the laminated structure is formed. ) On the side,
Second layer (B) including a three-layer structure in the structure example of FIG.
Have a structure in which the film (3) is inwardly bonded via an adhesive layer (a).

In the heat-resistant moisture-proof film according to the present invention, the basic function of the moisture-proof film is that of the first layer (A) of PVA.
This is realized by the SO thin film formed on the film surface being protected by the second layer (B). And it is presumed that the above-mentioned excellent moisture-proof properties are exhibited based on the following actions. Generally, S formed on the PVA film surface
The bonding energy of silicon of the O thin film shows a peculiar value in the thickness direction of the thin film, has a larger energy in the vicinity of the film than in the surface layer and the center, and the PVA film on which the SO thin film is formed can be formed at room temperature. Has excellent moisture-proof performance.

However, in a high-temperature and high-humidity atmosphere, the PVA film absorbs moisture and causes a dimensional change, thereby destroying the SO thin film on the surface, and impairing the moisture resistance at the corner. Although the above problem may be solved by protecting the PVA film with a film, the ordinary film or the PVDC film or the PVDC-coated film has a significant deterioration in the moisture-proof performance at high humidity, and the 5
At 0 ° C. or higher, the effect of preventing the PVA film from absorbing moisture can hardly be expected. On the other hand, the transparent laminated film having the SO thin film used as the second layer (B) in the present invention has very little deterioration of the moisture-proof performance in the high-temperature region. It is considered that the transparent film is effectively protected, and the excellent moisture-proof performance of the PVA film on which the SO thin film is formed can be maintained even in a high temperature region.

In the heat-resistant moisture-proof film according to the present invention, the sum of the absolute values of the heat shrinkage in the vertical and horizontal directions when heated at 150 ° C. for 30 minutes in the second layer (B) is 1% or less. For example, at the time of sealing an EL element, the SO thin film of the second layer (B) does not crack and the base film of the first layer (A) bonded thereto does not shrink when the EL element is sealed. It is considered that the occurrence of cracks in the SO thin film on the surface of the base film is effectively prevented. Therefore, the heat-resistant moisture-proof film according to the present invention can be sufficiently used as a package film for an EL element that can be used not only for a backlight of a liquid crystal display but also for an automobile or lighting.

[0053]

The present invention will now be described by way of Examples and Comparative Examples.
Although described in more detail, 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 was measured by the following method. (1) Thickness of SO thin film It was measured by a quartz-type film thickness meter when forming the thin film. (2) Heat Shrinkage Rate (%) The film was heated in a hot air oven at 150 ° C. for 30 minutes, and determined from the change rate of the vertical and horizontal dimensions before and after heating.

[0054] (3) from moisture permeability ^(gr / m 2 · 24H) predetermined moisture-proof film, to create a bag 3-way seal 70 × 70 mm (seal width 5 mm), into a bag, alternative EL element As, put thickly-absorbed cardboard with strong hygroscopicity,
The remaining one side was sealed between the two heated rubber rolls to obtain a cardboard-enclosed 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 film was allowed to stand for about 500 hours in an atmosphere of RH, and the moisture permeability of the moisture-proof film was determined from the change in the overall weight. (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. <Laminated film (A)> PV having a saponification degree of 99.9 mol%
A as a base film, a biaxially stretched film (stretching magnification: 3 × 3 times, thickness: 12 μm) made of A
Under an electron beam heating method under a vacuum of × 10-5 torr,
Heat-evaporated silicon monoxide (SiO) having a purity of 99.9% to form a transparent SO thin film having a thickness of 1000 °.

<Laminated Film (B)> The following laminated films (B-1) and ((B-1)) were used in combination: (1) Laminated film (B-1) Polyethylene terephthalate (hereinafter, "PET") Biaxially stretched film (stretch ratio 3 × 3 times,
Two thin films having a thickness of 1000 mm were formed on one side of a film having a thickness of 12 μm by the same method as described above.
One in which one SO thin film surface and the other non-SO thin film surface are bonded with a urethane-based adhesive. (2) Heat-resistant film (B-2) A 50 μm-thick unstretched film made of polyethersulfone resin, and the shrinkage after heating at 150 ° C. for 30 minutes has a shrinkage of 0.1 in the machine direction (MD). 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 by using a urethane-based adhesive (hereinafter simply referred to as “adhesive”). Then, a laminated film (B
-1) The SO thin film surface and the heat-resistant film (B-2) were joined using an adhesive to form a four-layer laminated film.

The above-mentioned sealant film (C) is bonded to the side of the laminated film (A) of the laminated film having a four-layer structure by using an adhesive, and a transparent laminated film having a five-layer structure as shown in FIG. 4 is obtained. Obtained. About the obtained laminated film,
As an alternative test of the EL element sealing step, the moisture permeability was measured by the method described above. Further, the transparency was measured by the method described above. Tables 1 to 3 show these results 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] [manufactured by Mitsui Toatsu Chemicals, Inc., trade name: TALPA
-1000 (Tg: 225 ° C.) PSF: A film made of a polysulfone resin having a repeating unit represented by (2) in the above chemical formula [Chemical Formula 3] [Sumilite FS, trade name, 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 above chemical formula [Chemical Formula 5] [Espec-R, trade name, manufactured by Sumitomo Chemical Co., Ltd.] (T
g: 193 ° C.) PI: A film made of a polyimide resin having a repeating unit represented by the formula (17) in the 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 structures of the obtained laminated films and the measurement results of the physical properties. In addition, the sealant film in each laminated film is the same as that of Example 1, and the description is omitted in Table 1. As is clear from the results shown in Tables 1 to 3, by including a predetermined heat-resistant transparent film in the second layer (B), a heat-resistant moisture-proof film having improved moisture permeability and transparency can be obtained. 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 properties. And it is flexible and excellent in strength and economy. In addition, 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-proof performance, such as package films such as EL elements for liquid crystal displays used for a long time under severe conditions, and its industrial value is extremely large. is there.

[Brief description of the drawings]

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

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

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

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

FIG. 5 is a cross-sectional view showing a specific structure example of a 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

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI H05B 33/04 H05B 33/04 (56) References JP-A-2-258251 (JP, A) JP-A-3-203634 (JP) , A) JP-A-3-203635 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (5)

(57) [Claims] 1. A first layer (A) defined as follows:
It comprises a second layer (B) and a third layer (C), wherein 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. Heat-resistant moisture-proof film. (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 degree of saponification of 99 mol% or more and a transparent silicon oxide thin film formed on at least one surface thereof. Consisting of a body or a laminate. (B) The second layer (B) is composed of a single layer or a laminate of a film made of a transparent plastic other than polyvinyl alcohol, and at least one side of at least one layer of the film has a transparent silicon oxide of 100 to 5000 °. A thin film was formed, and the sum of the absolute values of the heat shrinkage in the vertical and horizontal directions when heated at 150 ° C. for 30 minutes was 1% or less, and the light transmittance according to ASTM D-1003 was 85%.
% Or more of the heat-resistant transparent film. (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 thickness is in the range of 00 µm. 3. The heat resistance 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 [1]. Moisture proof film. Embedded image 4. The method according to claim 1, wherein the silicon oxide thin film is formed by any one of a vacuum deposition method, a sputtering method, and an ion plating method. 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, in the range of 100 to 5000 °, and the total thickness of the second layer (B) and the third layer (C) is in the range of 50 to 1000 μm. 2. The heat-resistant moisture-proof film of 1.