JP2001277420A - Transparent gas barrier film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent gas barrier film having a gas barrier film, which has high gas barrier properties even if thin, formed thereon. SOLUTION: In the transparent gas barrier film 1 wherein a gas barrier film 5 comprising an inorganic compound is provided on the single surface or both surfaces of a base material 2, the gas barrier film 5 is formed by forming a first film 3 comprising the inorganic compound on the base material and subsequently dissolving the surface of the first film 3 by a chemical etching liquid and again forming a second film 4 comprising the inorganic compound on the surface after dissolving of the first film 3. At this time, the inorganic compound is silicon oxide and the chemical etching liquid is preferably hydrofluoric acid, an ammonium fluoride aqueous solution or a mixed solution of them and the first and second films are preferably formed by a plasma CVD method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent gas barrier film having a gas barrier film made of an inorganic compound, which is preferably used as a packaging material for foods and pharmaceuticals or a packaging material for electronic devices.

[0002]

2. Description of the Related Art Transparent gas barrier films are mainly
(B) Used as a packaging material for foods and pharmaceuticals, or (b) formed on liquid crystal display panels or EL display panels, etc., in order to prevent the effects of oxygen, water vapor, etc., which cause the quality of the contents to change. It is used as a package material for electronic devices and the like in order to avoid the performance deterioration of some elements due to contact with water vapor. For transparent gas barrier films,
What sticks a film with gas barrier properties,
Conventionally, a film having a gas barrier property is formed by wet or dry film formation.

[0003] In particular, a film having a gas barrier property formed of an inorganic compound such as silicon oxide (hereinafter referred to as "gas barrier film") is a film for packaging which requires a higher gas barrier property due to its excellent gas barrier property. It is preferably used for packaging films. Such a gas barrier film can be formed by a method such as a vacuum deposition method, a sputtering method, an ion plating method, a thermal CVD method, or a plasma CVD method.
It is formed by applying the VD method. Among these, the plasma CVD method can form a gas barrier film made of an inorganic compound such as silicon oxide at a low temperature at which thermal damage is not applied to the polymer resin. It is preferably applied.

In order to provide such a transparent gas barrier film with high gas barrier properties, it is necessary to form the above gas barrier film thick.

[0005]

However, when the above-mentioned gas barrier film made of an inorganic compound such as silicon oxide is formed to be thick, (a) it takes a long time to form the film, and the productivity decreases. B) There is a problem that cracks are generated due to the internal stress of the gas barrier film, and the gas barrier property is rather deteriorated. Such issues are raised by the Society of Vacuu
m Coaters, JTFelts et al. (34th Annual Technic
al Conference Proceedings (1991), p.99-104), JEK
lemberg-Sapieha et al. (36th Annual Technical Conference
Proceedings (1993), p.445-449).

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. In a transparent gas barrier film having a gas barrier film made of an inorganic compound, a transparent gas barrier film having a thin but high gas barrier film is formed. I will provide a.

[0007]

The transparent gas barrier film of the present invention has a gas barrier film made of an inorganic compound on one or both surfaces of a substrate, wherein the gas barrier film is made of a first material made of the inorganic compound. After forming the film of, dissolve the surface of the first film with a chemical etching solution,
It is characterized in that a second film made of the inorganic compound is formed again on the surface of the first film after the dissolution.

The present invention relates to a method for forming a first film made of an inorganic compound, dissolving the surface of the first film with a chemical etching solution, and then forming a second film made of an inorganic compound again. A transparent gas barrier film having a high gas barrier property as compared with a transparent gas barrier film having a single gas barrier film of the same thickness, which is based on the fact that a high gas barrier property is developed in the obtained gas barrier film. It can be. As a result, the gas barrier film can be made thinner, so that the efficiency of the gas barrier film formation process can be improved, the productivity of the transparent gas barrier film can be improved, and cracks due to the internal stress of the gas barrier film can occur. Absent. The transparent gas barrier film thus obtained can be used as a material having high gas barrier properties even for applications requiring flexibility.

In the above transparent gas barrier film,
The inorganic compound is silicon oxide, and the chemical etching solution is a hydrofluoric acid, an ammonium fluoride aqueous solution, or a mixed solution thereof.

According to the present invention, a gas barrier film is formed of silicon oxide, and a hydrofluoric acid, an ammonium fluoride aqueous solution, or a hydrofluoric acid aqueous solution is used as a chemical etching solution for dissolving the surface of the first film made of the silicon oxide. By using a mixed solution of the above, a transparent gas barrier film having excellent gas barrier properties can be produced. At this time, since the surface of the first film can be dissolved by using an inexpensive chemical etching solution and a relatively simple processing apparatus, the manufacturing cost can be reduced.

In the above transparent gas barrier film,
It is preferable that the first film and the second film made of the inorganic compound are formed by a plasma CVD method.

According to the plasma CVD method, a gas barrier film made of an inorganic compound can be formed at such a low temperature that thermal damage is not applied to a polymer resin. Therefore, it is easy to produce a transparent gas barrier film using a polymer film as a base material. . Further, since the film forming conditions can be easily controlled and the quality of the obtained film can be easily changed, the solubility of the above-mentioned first film in the chemical etching solution and the surface of the first film after being dissolved. The form can be adjusted arbitrarily. Furthermore, in the plasma CVD method, the interface between the formed first film and the substrate can be chemically bonded, so that the adhesion between the two can be sufficiently increased.

In the above transparent gas barrier film,
The gas barrier film has a thickness of 10 to 200 nm, an oxygen transmission rate of 0.5 cc / m ² / day or less, and a water vapor transmission rate of 0.5 g / m ² / day or less.

According to the present invention, even when the thickness of the gas barrier film is formed as thin as 10 to 200 nm, a transparent gas barrier film having the above-described oxygen permeability and water vapor permeability can be manufactured. .

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a process flow chart of a process for producing a transparent gas barrier film of the present invention. The transparent gas barrier film 1 of the present invention has a gas barrier film 5 made of an inorganic compound on one or both surfaces of a substrate 2 as shown in FIG. Then, the gas barrier film 5
Forms a first film 3 made of an inorganic compound.
(A)) and then the first film 3 with a chemical etching solution
Is dissolved (FIG. 1 (b)), and on the surface of the first film 3 after the dissolution (FIG. 1 (c)), a second film 4 made of the same inorganic compound as described above is formed again (FIG. 1 (b)). 1 (d)). Therefore, in the present invention, the gas barrier film 5 formed through at least such a process may be used.
The surface of the second film 4 is dissolved with a chemical etching solution, and the surface of the second film 4 after the dissolution is again coated with a third film (similarly, a fourth film, Five films) are also included in the present invention. afterwards,
By providing another laminated material 6 as needed, the transparent gas barrier film 1 of the present invention is manufactured.
(E)).

In the present invention, (i) the chemical etching solution selectively dissolves and removes the low-crystalline grain boundary region in the first film, which has a poor gas barrier effect, and (ii)
By forming the second film again, fine particles of high crystallinity also having excellent gas barrier effect are newly formed in the high crystallinity region having excellent gas barrier effect remaining without being dissolved. A gas barrier film was produced. The present inventor has found that the gas barrier film thus produced is a dense film having an excellent gas barrier action, and has achieved the present invention. As a result, the transparent gas barrier film 1 having the gas barrier film 5 formed by the above-described process has a higher gas barrier property than the transparent gas barrier film having the same thickness gas barrier film formed by a single process. Has the characteristic that it can exhibit

Hereinafter, the transparent gas barrier film of the present invention will be described while explaining the manufacturing process shown in FIG.

(1) Formation of First Film First, as shown in FIG. 1A, a first film 3 made of an inorganic compound is formed on one or both surfaces of a substrate 2.

As the substrate 2, a transparent film made of a polymer resin is used. Typical examples are polyethylene terephthalate (PET) film, biaxially oriented polypropylene (OPP) film, and biaxially oriented polyamide (ONy), which are generally used as packaging materials for packaging films for foods, pharmaceuticals, and other electronic devices. ) Film, polyimide (PI) film, polyethylene (PE) film, polyethylene naphthalate (PE)
N) film, polycarbonate (PC) film, cyclic polyolefin (CPO) film, ethylene-tetrafluoroethylene copolymer (ETFE) film, and the like. Since these films are excellent in mechanical strength and dimensional stability, they can be manufactured stably even when a tensile force is applied during the film formation by the PVD method or the CVD method or during the manufacturing process after the film formation. it can. Furthermore, since those films are also excellent in surface smoothness, there is an advantage that the first film 3 made of an inorganic compound can be easily formed uniformly. The base material 2 is conveniently a long product wound up in a roll shape. The thickness of the substrate 2 varies depending on the use of the obtained transparent gas barrier film 1 and cannot be unconditionally specified. However, when the substrate 2 is used as a general packaging material or a substrate for a packaging material, the thickness is preferably 3 to 188 μm.

On the surface of the substrate 2, an anchor coat treatment layer for improving the adhesion to the first film 3 can be provided as required. The anchor coat treatment is performed on the substrate 2
During or after the production of the plastic film, which can be performed by a secondary processing or the like. Examples of the anchor coating agent for providing the anchor coating layer include polyester resin, isocyanate resin, urethane resin, acrylic resin, ethylene vinyl alcohol resin, vinyl modified resin, epoxy resin, modified styrene resin, modified silicone resin, and alkyl titanate. Can be used alone or in combination of two or more.
Conventionally known additives can be added to the anchor coat agent. In addition, the surface of the substrate 2 is subjected to a corona discharge treatment, a plasma treatment in a vacuum or in the air, a flame treatment, a glow discharge treatment, a surface roughening treatment, a chemical treatment, etc. Between them can also be improved.

The first film 3 is made of an inorganic compound having gas barrier properties, and is formed on one or both surfaces of the base material 2. Whether the first film 3 is formed on one side or both sides is arbitrarily selected depending on the use and usage of the finally obtained transparent gas barrier film.

Examples of the inorganic compound constituting the first film 3 include those having a gas barrier property, such as silicon oxide, aluminum oxide, magnesium oxide, and silicon nitride. Above all, a film made of silicon oxide exhibits a high gas barrier property, and is therefore preferably used as the first film 3 and thus the gas barrier film 5.

The first film 3 is formed by applying a method such as a vacuum evaporation method, a sputtering method, an ion plating method, or a thermal CVD method or a plasma CVD method. These methods are selected in consideration of the type of the base material, the type of the film forming material, the ease of film formation, the process efficiency, and the like.

Of these, the plasma CVD method uses the first film 3 made of an inorganic compound such as silicon oxide at a low temperature (in the range of about -10 to 150 ° C.) at which the polymer resin is not thermally damaged. Since the second film 4 and the second film 4 can be formed, it is preferably applied to the formation of the gas barrier film 5 of the transparent gas barrier film 1 using the polymer film as the base material 2.
Further, the plasma CVD method is a method in which a source gas at a constant pressure is discharged into a plasma state, and a chemical reaction is promoted and formed on a substrate surface by active particles generated in the plasma. There is an advantage that the type and physical properties (film quality) of the obtained film can be controlled by the type / flow rate, film forming pressure, input power and the like. Furthermore, when the first film 3 is formed by the plasma CVD method, the first film 3 and the base material 2 are chemically bonded at the interface, so that the adhesion between the two can be sufficiently increased.

For example, when the first film 3 made of silicon oxide is formed, a mixed gas of an organic silicon compound gas and an oxygen gas is supplied at a predetermined flow rate into a reaction chamber of a plasma CVD apparatus, and the electrode is formed. DC power or power having a constant frequency in the range of low frequency to high frequency is applied to generate plasma, and the organosilicon compound gas and oxygen gas react in the plasma, thereby forming the second silicon oxide. One film 3 is formed on the substrate 2. The type of plasma CVD apparatus used is not particularly limited, and various types of plasma CVD apparatuses can be used. Usually, an apparatus capable of continuously forming the first film 3 made of silicon oxide while using a long polymer resin film as the substrate 2 and transporting the same is preferably used.

The mixed gas for forming the first film 3 made of silicon oxide includes (I) hexamethyldisiloxane (HMDSO), 1,1,3,3-tetramethyldisiloxane (TMDSO), vinyl Trimethoxysilane, vinyltrimethylsilane, tetramethoxysilane (TMO
S), a mixture of an organic silicon compound gas such as methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, or hexamethyldisilazane, and oxygen gas, or (II) a silane-based gas, oxygen gas or oxidized gas. a mixture of the object gas, for example, a SiH ₄ gas, N ₂ O gas, NO gas, CO gas, CO ₂ gas, O
_A mixed gas of _two gases, Ar gas and the like can be preferably used.

For example, when the first film 3 made of a silicon nitride film (Si ₃ N ₄ ) is formed, a mixed gas of SiH ₄ + NH ₃ gas, hexamethyldisilazane (HMDS) + O ₂ gas is used. And the like can be preferably used. At this time, hexamethyldisilazane (HMDS) + O
_{When the} film is formed using _two gases, the film is a SiN _x O _y film.

The first film formed as described above contains components derived from a mixed gas as a raw material, such as carbon atoms when an organic silicon compound gas is used. There is.

The film forming conditions of the first film 3 thus formed are set in consideration of the dissolution behavior in a chemical etching solution described later, and the film quality is controlled. Usually, it is preferable that the thickness be in the range of 5 to 50 nm. If the thickness is less than 5 nm, a sufficient film covering the surface of the substrate 2 may not be formed. On the other hand, the thickness is 50n
Even if it exceeds m, there is no particular problem, but it is considered that the grain boundary region 12 having low crystallinity is formed, so that it is not necessary to increase the thickness.

(2) Dissolution by Chemical Etching Solution Next, as shown in FIGS. 1B and 1C, the surface of the formed first film 3 is dissolved by a chemical etching solution.

The first film 3 is selectively dissolved and removed by the chemical etching solution in the low crystal grain boundary region 12 which is inferior to the gas barrier function and exists in the first film. FIG.
FIG. 3 and FIG. 3 are explanatory views of the dissolution behavior when the first film 3 made of silicon oxide is dissolved with a chemical etching solution made of hydrofluoric acid. FIG. 2 is a cross-sectional view showing an example of the surface morphology of the first film 3 before dissolving with the chemical etching solution, and FIG. 3 is a surface morphology of the first film 3 after dissolving with the chemical etching solution. FIG. 3 is a cross-sectional view showing one example.

The first film 3 made of silicon oxide is composed of fine highly crystalline grain regions 11 which are relatively hard to dissolve in a chemical etching solution made of hydrofluoric acid, and a chemical etching solution between the grain regions 11. And a low-crystalline grain boundary region 12 that is easily melted selectively. When a chemical etching solution is brought into contact with the surface of the first film 3, the grain boundary region 12 is selectively dissolved and removed, and changes from the smooth surface form shown in FIG. 2 to the fine uneven surface form shown in FIG. 3. The change is observed by an atomic force microscope (AFM). The atomic force microscope is, for example, Nano Instruments manufactured by Digital Instruments.
Models such as Scope III, Seiko Denshi, Topometrix, etc. of the same type can be used.

Such a dissolution phenomenon is explained as follows. That is, in the formation of a film by a method such as the PVD method or the CVD method, islands are formed by nucleation and nucleus growth that occurs around the nuclei. Formed and grained regions 11
(In the present invention, this is referred to as “highly crystalline grain region 11”.)
Is formed. As long as the islands are small, when the islands come into contact and coalesce, even if their crystallinities are different, crystal rearrangement occurs, resulting in a more stable structure. However, when the island is large, such rearrangement does not occur, and even if the islands come into contact with each other, they do not unite, and an amorphous boundary surface with low crystallinity is generated. The above-described grain boundary region 12 is a portion having low crystallinity (referred to as “low-crystal grain boundary region 12” in the present invention) including this boundary surface and a portion in the vicinity thereof, and is permeable to gases such as oxygen and water vapor. This is a factor that deteriorates gas barrier properties. However, since the grain boundary region 12 is considered to be in a state where the surface energy is high due to the occurrence of distortion due to lattice defects and dislocations, the grain boundary region 12 is smaller than the grain region 11 where the lattice defects and the like are considered to be small. It is considered that the chemical etching solution is in a state of being easily dissolved by the attack. Therefore, in the present invention, by bringing the chemical etching solution into contact with the surface of the first film 3, the grain boundary region 12 is dissolved, and the surface shape is changed to a minute uneven surface as shown in FIG. 3. it is conceivable that.

Although the solubility of the first film 3 is affected by the film forming conditions, in the present invention, the film quality is easily controlled by the film forming conditions such as a method such as a PVD method or a CVD method. Thus, the solubility can be adjusted. In particular, the above-described plasma CVD method has an advantage that the film quality is easily controlled by changing the film forming conditions.

The chemical etching solution is arbitrarily selected depending on the type of the inorganic compound constituting the first film 3 and a solution capable of selectively dissolving and removing the low-crystalline grain boundary region 12 having a poor gas barrier effect. . For example, in the case of the first film 3 made of silicon oxide, it is preferable to use hydrofluoric acid, an aqueous solution of ammonium fluoride, or a mixed solution thereof. Examples of the chemical etching solution include hydrofluoric acid and ammonium fluoride aqueous solutions, corrosive substances containing oxidizing agents and their solutions, and other acidic aqueous solutions such as nitric acid aqueous solution, ferric chloride aqueous solution, and hydrochloric acid aqueous solution. Can be arbitrarily selected and used.

The dissolution rate and dissolution state of the first film 3 can be adjusted by arbitrarily changing the concentration, the treatment time, the treatment temperature and the like of the chemical etching solution. For example, when using hydrofluoric acid for the first film 3 made of silicon oxide, hydrofluoric acid is arbitrarily adjusted to a concentration of 50% by mass or less, and a predetermined concentration in a range of 0 to 100 ° C. Processing can be performed by appropriately setting the temperature. Actually, since the quality of the first film 3 is greatly affected, each processing condition is set according to the type of the first film 3 and the surface state after dissolution. When an ammonium fluoride aqueous solution is used instead of hydrofluoric acid,
Alternatively, when a mixed solution of hydrofluoric acid and an aqueous solution of ammonium fluoride is used, the respective processing conditions are set in the same manner as described above.

As a method of bringing the chemical etching solution into contact with the surface of the first film 3, a vapor treatment, a dipping treatment immersed in the aqueous solution, a spray treatment spraying the aqueous solution, or the like can be performed. There is no particular limitation.

(3) Formation of Second Film Next, as shown in FIG. 1D, a second film 4 made of an inorganic compound is formed again on the surface of the first film 3 after dissolution. Thus, the gas barrier film 5 is manufactured. FIG.
FIG. 4 is a cross-sectional view showing an example of a form in which a second film 4 is formed on the surface of the first film 3 shown in FIG.

In the second film 4, fine grains 13 of the same high crystallinity are newly generated in the high-crystalline grain regions 11 remaining undissolved on the surface of the first film 3 and grow. It is formed by doing. Since the highly crystalline grain regions 11 are exposed on the surface of the first film 3 after dissolution, nucleation during the formation of the second film 4 is likely to occur.

The gas barrier film 5 thus produced is composed of a highly crystalline grain region 11 remaining undissolved on the surface of the first film 3 and a highly crystalline grain region 11 newly formed on the first surface 3. The dense grains 13 form a dense and highly crystalline region. Since the highly crystalline grain region 11 and the highly crystalline grain 13 both have an excellent gas barrier action, the produced gas barrier film 5 can exhibit high gas barrier properties.

The second film 4 is usually formed by the same method as that for forming the first film 3 as described above, but may be formed by a different method. For example, if the first film 3 is a plasma C
When the second film 4 is formed by the VD method, the plasma C
Although it is preferable to form by a VD method, it is also possible to form by a different method such as an ion plating method. The film forming conditions are usually set to the same conditions as in the case of the first film 3.

The thickness of the second film 4 thus formed is
Preferably, it is formed in the range of 5 to 50 nm. If the thickness is less than 5 nm, a sufficient film 4 covering the surface of the first film 3 may not be formed. On the other hand, the thickness is 50 nm
This does not cause any particular problem even if the thickness exceeds the range, but it is considered that the grain boundary region 12 having low crystallinity is formed, so that it is not necessary to increase the thickness.

The gas barrier film 5 is formed by the first film 3 and the second film 4, and the thickness of the gas barrier film 5 is preferably 10 to 200 nm, more preferably 10 to 100 nm. In the present invention, even such a thin gas barrier film 5 exhibits high gas barrier properties. If the thickness of the gas barrier film 5 is less than 10 nm, it may not have sufficient gas barrier properties.

On the other hand, even if the thickness of the gas barrier film exceeds 200 nm, there is no problem in terms of gas barrier properties, and such a gas barrier film can be formed. However, there may be a manufacturing problem that productivity is reduced and cracks are generated due to internal stress. Furthermore, the flexibility of the obtained transparent gas barrier film decreases, and it cannot be used as an application requiring flexibility such as a packaging material, or the transparency or appearance decreases, and the curl of the film increases. Or other problems may occur.

The transparent gas barrier film of the present invention is not required to be relatively thin, such as a gas barrier film for a film liquid crystal display, a gas barrier film for a film organic EL display, or a gas barrier film for a film solar cell. In this case, gas barrier properties are required first. Therefore, the above 10 to 200
Within the thickness range of nm, the thickness of the gas barrier film is
It is preferable to make the thickness relatively thicker than in the above-mentioned applications requiring flexibility.

In the present invention, it is sufficient that the gas barrier film 5 is formed at least through the above-described process. Thereafter, the surface of the second film 4 is dissolved with a chemical etching solution, On the surface of the film 4, a third film made of the same inorganic compound as described above, and a fourth film, a fifth film, and the like can be sequentially formed by the same method. The grains constituting each film are large, about 5
When the third film is formed, for example, the first film 3 is formed to have a thickness of about 50 nm, the surface thereof is dissolved, and then the second film 4 is formed to about 80 nm. A gas barrier film having a thickness of about 150 nm can be formed by forming a layer having a thickness of 50 nm, dissolving the surface thereof, and further forming a third film having a thickness of about 50 nm. Similarly, a gas barrier film composed of more layers can be formed.

(4) Transparent Gas Barrier Film Finally, as shown in FIG. 1E, another laminated material 6 is placed on the gas barrier film 5 composed of the first film 3 and the second film 4.
Is provided as needed to produce the transparent gas barrier film 1 of the present invention.

As the other laminated material 6, a material appropriately selected according to the use of the transparent gas barrier film 1 is provided. For example, low density polyethylene film (LDP)
E, LLDPE) or cast polypropylene film (CPP) can be laminated on the gas barrier film 5 via a urethane-based adhesive or an isocyanate-based adhesive. In addition, an ethylene-vinyl acetate copolymer film (EV
A) can be formed on the gas barrier film 5 by an extrusion lamination method and laminated.

The transparent gas barrier film 1 of the present invention includes
Further, a laminated material formed by a wet film formation such as a dry film formation or a coating method such as a PVC method or a CVD method is applied between the base material 2 and the first film 3 and on the back side of the base material 2. It is also possible to laminate as necessary. At this time, the first film 3 is formed on the surface of the substrate 2 within a range that does not impair the object of the present invention.
An anchor coat treatment layer can be provided for the purpose of improving the adhesion to the coating. Examples of the anchor coating agent for providing the anchor coating layer include polyester resin, isocyanate resin, urethane resin, acrylic resin, ethylene vinyl alcohol resin, vinyl modified resin, epoxy resin, modified styrene resin, modified silicone resin, and alkyl titanate. Can be used alone or in combination of two or more. Conventionally known additives can be added to these anchor coating agents.

The transparent gas barrier film 1 of the present invention
The term “transparent” as used in the above is merely related to the gas barrier film. Therefore, it is free to arbitrarily laminate a layer having inferior transparency among the base material 2 and other laminated materials for use in various applications, and the transparency of the transparent gas barrier film 1 required as a final product and its transparency The extent depends on the various applications. For example, when the transparent gas barrier film 1 of the present invention is used as a packaging material, it may be printed with colored ink or the like to provide light-shielding properties in order to protect the contents from light rays. In addition, it is possible to laminate a layer in which an additive such as an antistatic agent and a filler, which has a factor of deteriorating the transparency of the whole transparent gas barrier film, is laminated, or a non-transparent metal foil is laminated. However, when used in applications such as a gas barrier film for a film liquid crystal display, a gas barrier film for a film organic EL display, or a gas barrier film for a film solar cell, the transparency of the entire transparent gas barrier film is required. The effect due to the transparency of the film is great.

The transparent gas barrier film 1 in which the gas barrier film 5 has a thickness of 10 to 200 nm, preferably 10 to 100 nm has an oxygen permeability of 0.5 cc / m ² / da.
the water vapor transmission rate is 0.5 g / m ² / day or less at y or less,
More preferably, the oxygen permeability is 0.1 cc / m ² / day
Under the above conditions, a very excellent gas barrier property having a water vapor transmission rate of 0.3 g / m ² / day or less is exhibited. Since the transparent gas barrier film 1 of the present invention hardly permeates oxygen and water vapor that cause the quality of the contents to change, it is used for applications requiring high gas barrier properties, such as packaging materials for foods and pharmaceuticals, and electronic devices. It can be preferably used for package materials.

[0052]

The present invention will be described more specifically with reference to the following examples and comparative examples.

(Example 1) As a substrate 2, a thickness of 12 μm
Polyethylene terephthalate (PET) film (PTM, manufactured by Unitika) was used. A first film 3 made of silicon oxide was formed on one surface of the substrate 2 by a plasma CVD method. As a plasma CVD apparatus, a parallel plate type plasma C having a low frequency power supply of a frequency of 90 kHz is used.
A VD device (manufactured by Anerva, PED-401) was used.
As a film forming condition, a hexamethyldisiloxane (HMDSO) gas (Toray Dow Corning Silicone Co., Ltd., SH200, 0.65CSt) 1.5 is used as a source gas.
sccm, oxygen gas (Taiyo Toyo Oxygen Co., Ltd., purity 99.
9999%) 15sccm, helium gas 30sc
cm, an input power of 250 W, and a film forming pressure of 33.325.
The film was formed at a pressure of Pa (250 mTorr) by adjusting the film formation time until the film thickness became 20 nm. Sccm standsa
rd cubic cm per minute.

Next, the obtained first film 3 was treated with 0.5% by mass of hydrofluoric acid (23%) used as a chemical etching solution.
C) for 10 seconds, washed with water and dried,
The surface of the first film 3 made of silicon oxide was dissolved.

Then, a second film 4 made of silicon oxide is formed on the first film 3 after dissolving under the same apparatus and conditions as those for forming the first film 3. A gas barrier film 5 composed of the film 3 and the second film 4 was produced and used as a test sample of Example 1. At this time, the deposition time of the second film 4 was adjusted so that the entire thickness of the gas barrier film 5 became 50 nm. In addition, the film thickness is TEM (transmission electron microscope)
Determined by

The obtained test sample was subjected to oxygen gas permeability measurement and water vapor permeability measurement to evaluate gas barrier properties. The oxygen gas permeability is measured using an oxygen gas permeability measuring device (M
Using OX-TRAN 2/20 manufactured by OCON,
The measurement was performed under the conditions of 3 ° C. and dry (0% Rh). The water vapor transmission rate is measured using a water vapor transmission rate measurement device (manufactured by MOCON, PE
RMATRAN-W 3/31) at 37.8 ° C.
The measurement was performed under the condition of 100% Rh. The evaluation criterion for gas barrier properties is that the oxygen gas transmission rate (OTR) is 0.5 cc / m ² /
day or less, and the water vapor transmission rate (WVTR) was 0.5 g / m ² / day or less. Note that cc is m
1 (milliliter).

(Comparative Example 1) A gas barrier film 5 consisting of only the first film 3 having a thickness of 50 nm was formed by a single film forming operation under the same apparatus and conditions as in Example 1, and the test sample of Comparative Example 1 was prepared. And Evaluation of the gas barrier properties of the obtained test sample was performed in the same manner as in Example 1.

Comparative Example 2 A first film 3 having a thickness of 20 nm was formed under the same apparatus and conditions as in Example 1. Thereafter, the second film 4 was formed without performing the dissolving treatment, and a 50 nm-thick gas barrier film 5 composed of the first film 3 and the second film 4 was formed. A sample was used. Evaluation of the gas barrier properties of the obtained test sample was performed in the same manner as in Example 1.

(Evaluation results)

[Table 1]

The test sample of Example 1 exhibited excellent gas barrier properties, whereas the test samples of Comparative Examples 1 and 2 evaluated both oxygen gas transmission rate (OTR) and water vapor transmission rate (WVTR). It exceeded the standard and showed insufficient gas barrier properties.

[0061]

As described above, according to the transparent gas barrier film of the present invention, (i) a low-crystalline grain boundary region having a poor gas barrier effect existing in the first film is selected by the chemical etching solution. (Ii) by forming a second film again, the high crystallinity region excellent in gas barrier function remaining undissolved in the high crystallinity region also excellent in gas barrier effect Since a gas barrier film was prepared by newly forming fine particles, a transparent gas barrier film having the gas barrier film was compared with a transparent gas barrier film having a gas barrier film of the same thickness formed in a single process. High gas barrier properties can be exhibited. As a result, the gas barrier film can be made thinner, so that the efficiency of the gas barrier film formation process can be improved, the productivity of the transparent gas barrier film can be improved, and cracks due to the internal stress of the gas barrier film can occur. Absent. The transparent gas barrier film thus obtained is
Even for applications requiring flexibility, it can be used as having high gas barrier properties.

[Brief description of the drawings]

FIG. 1 is a process flow chart of a process for producing a transparent gas barrier film of the present invention.

FIG. 2 is a cross-sectional view showing an example of a surface configuration of a first film before being dissolved by a chemical etching solution.

FIG. 3 is a cross-sectional view showing an example of a surface form of a first film after being dissolved by a chemical etching solution.

FIG. 4 is a cross-sectional view showing an example of a form in which a second film is formed on the surface of the first film shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent gas barrier film 2 Substrate 3 First film 4 Second film 5 Gas barrier film 6 Laminated material 11 Grain area 12 Grain boundary area 13 grains

Continued on the front page F-term (reference) 3E086 BA04 BA15 BB02 BB05 BB22 CA01 CA28 CA31 DA02 DA08 4F071 AA46 AF08Y AF09Y BC01 4F100 AA01B AA01C AA01D AA01E AA20B AA20C AA20D AA20EBA66E10 BA05 BAO EJ15B EJ15D GB15 GB23 JD02B JD02C JD02D JD02E JD03 JD04 JN01B JN01C JN01D JN01E YY00 4K030 BA44 BB13 CA07 CA12 DA08 FA01 LA01

Claims (4)

[Claims] 1. A transparent gas barrier film having a gas barrier film made of an inorganic compound on one or both surfaces of a substrate, wherein the gas barrier film is formed by forming a first film made of the inorganic compound, and then forming a chemical etching solution. Wherein the surface of the first film is dissolved and a second film made of the inorganic compound is formed again on the surface of the first film after the dissolution. 2. The transparent gas barrier according to claim 1, wherein the inorganic compound is silicon oxide, and the chemical etching solution is hydrofluoric acid, an aqueous solution of ammonium fluoride, or a mixed solution thereof. the film. 3. The transparent gas barrier film according to claim 1, wherein the first film and the second film made of the inorganic compound are formed by a plasma CVD method. 4. The thickness of the gas barrier film is 10 to 200.
The oxygen permeability is 0.5 cc / m ² / day or less, and the water vapor permeability is 0.5 g / m ² / day or less. Transparent gas barrier film.