JPH1044303A - Gas barrier film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve gas barrier properties and to give chemical resistance by forming the cured coat of an active energy ray curable composition containing a silane coupling agent having an acryloyl group and/or a methacryloyl group on a metal oxide thin film formed on the surface of a plastic film. SOLUTION: In a gas barrier film, an active energy ray curable composition containing 0.2-45wt.% of a silane coupling agent having an acryloyl group and/or a metacryloyl group is applied on a metal oxide thin film formed on a plastic film by a vacuum vapor deposition method, etc., irradiated with active energy rays, and cured to form a cured coat. The improvement in the adhesion between the metal oxide thin film and the cured coat is attained by the chemical bond of the silane coupling agent to the metal oxide thin film and by the reaction of the acryloyl group and the methacryloyl group with another coexistent coat forming component, and the improvement in gas barrier properties is attained by the packing of the coat forming component in the gaps between the particles of the metal oxide coat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a film having excellent gas barrier properties, and more particularly to a gas barrier film suitable as a substrate film for a transparent electrode for a liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, the demand for liquid crystal display devices has been expanding, and the importance of transparent electrodes used in the devices has been increasing. Conventionally, as a transparent electrode for a liquid crystal display device, a thin film formed of a tin oxide-indium oxide thin film on a thin glass substrate has been widely used, but with the demand for thinner, lighter, and mass-produced devices, plastics have been developed. Transparent electrodes based on films have been used.

[0003]

However, the transparent electrode for a liquid crystal display device using a plastic film as a substrate has several problems. For example, the barrier properties against oxygen and water vapor of the substrate film required from the viewpoint of the reliability of the liquid crystal cell, the adhesion between the formed electrode and the film, the chemical resistance of the film required in etching, and the like. As means for solving these problems, a transparent electrode film for a liquid crystal display element having a laminated structure has been proposed. For example, Japanese Patent Application Laid-Open Nos. 61-32749 and
Japanese Patent Application Laid-Open No. 1-332750 describes a laminated conductive film in which a metal oxide layer is provided on a base film to prevent the transmission of water vapor and oxygen. However, the layered structure of the laminated conductive film in JP-A-61-32749 is a metal oxide layer such as a silicon oxide / polymer film / organic material layer / conductive layer, and an organic material layer is formed on the metal oxide thin film. not exist. In such a layer configuration, the oxygen permeability required as a transparent electrode film for a liquid crystal display element is 1
cc / m ² · atm · 24 hrs, water vapor permeability 1 g
It is difficult to attain a high barrier property of / m ² · 24 hrs.

The layer structure of a laminated conductive film disclosed in Japanese Patent Application Laid-Open No. 61-32750 is composed of a polymer film / a metal oxide layer such as silicon oxide / an organic material layer / a conductive layer. There is an organic layer of acrylic resin. However, in general, a coating formed by applying and curing an acrylic thermosetting or active energy ray-curable composition, even if it adheres to a plastic film, adheres to a metal oxide thin film. Is not always good and is not satisfactory as a conductive film for a liquid crystal display element. Therefore, the present invention solves the above problems, by having a cured film having excellent adhesion to a metal oxide thin film, gas barrier properties are improved, and a gas barrier film with chemical resistance is provided. It is intended to provide.

[0005]

An object of the present invention is to provide a plastic film having a metal oxide thin film formed on a surface thereof, on the metal oxide thin film, a silane coupling agent having an acryloyl group and / or a methacryloyl group. This is achieved by a film having a cured film of the active energy ray-curable composition contained therein.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail. As a plastic film as a base material of a gas barrier film according to the present invention, a wide variety of synthetic resins can be used. For example, polyethylene, polypropylene, polyolefin resins such as polybutene, polyethylene terephthalate, polyethylene
Polyester resins such as 2,6-naphthalate, polyamide resins such as nylon 6 and nylon 12, vinyl alcohol resins such as polyvinyl alcohol and ethylene-vinyl alcohol copolymer, furthermore, polyimide, polyetherimide, polysulfone, poly Ether sulfone, polyetheretherketone, polycarbonate,
A film made of a synthetic resin such as polyvinyl butyral, polyarylate, and cyclic polyolefin is used.
Further, a film or a laminated film composed of a mixture of two or more synthetic resins is also used. Known additives such as an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant, and a coloring agent may be added to the plastic film. The plastic film may be stretched,
It may not be stretched.

[0007] The thickness of the plastic film is not particularly limited, but is preferably in the range of 3 to 2000 µm, and more preferably in the range of 5 to 1000 µm in terms of mechanical strength and flexibility. Also, since the substrate film of the transparent electrode for a liquid crystal display element is required to be transparent,
It is preferable that the above-mentioned plastic film is also transparent. Prior to forming the metal oxide thin film, the plastic film may be subjected to a surface treatment such as a corona discharge treatment, a flame treatment, a plasma treatment, a glow discharge treatment, a surface roughening treatment, or may be provided with an anchor coat layer. Good.
When an anchor coat layer is provided, the gas barrier properties can generally be further improved.

As the material of the anchor coat layer, a thermosetting resin such as a polyester resin, a urethane resin, an acrylic resin, a vinyl-modified resin, an epoxy resin, a modified styrene resin, a modified silicon resin, or an alkyl titanate is used. These may be used alone or in combination of two or more. Further, additives such as a silane coupling agent and an ultraviolet absorber may be added.

The thickness of the anchor coat layer is 0.005 to 5
The range of μm is preferred. 0.005 anchor coat layer
If the thickness is less than μm, coating unevenness occurs, and the gas barrier property is not improved. On the other hand, if the thickness is more than 5 μm, the adhesion becomes poor. The method of forming the anchor coat layer is a gravure coating method,
Various resin coating methods such as a reverse coating method can be used.
Examples of the metal oxide thin film on a plastic film include silicon oxide, aluminum oxide, magnesium oxide, tin oxide, and a mixture of two or more of these, which are used to impart gas barrier properties to a plastic film. Any metal oxide thin film can be used. Also in the gas barrier film according to the present invention, the metal oxide thin film has a function of giving the film an oxygen barrier property and a water vapor barrier property.

The thickness of the metal oxide thin film varies depending on the purpose of use of the film, but is usually 50 to 5000 °. 5
If it is less than 0 °, the gas barrier properties are generally insufficient. On the other hand, when the thickness exceeds 5000 °, flatness tends to be impaired, for example, when a thin plastic film, for example, a plastic film having a thickness of 15 μm or less is used as a base material, curling occurs. In addition, since the silicon oxide thin film has a slightly yellow color, it is not suitable for applications requiring colorless transparency when the film thickness is large. There is also a problem that the color is shaded by a change in the film thickness. Generally, the preferred thickness of the metal oxide thin film is 100 to 2000 °.

The metal oxide thin film can be formed on the plastic film by any known method such as vacuum deposition, ion plating, sputtering, and CVD. When forming a silicon oxide thin film by vacuum deposition,
When oxygen gas or water vapor is introduced into the atmosphere, the transparency of the resulting thin film can be improved. In this case, the pressure of the atmosphere is usually 1 × 10 ⁻⁵ to 1 × 10 ⁻³ (Torr).
It is preferable to introduce the gas so as to fall within the range described above. When the pressure is 1 × 10 ⁻³ (Torr) or more, the gas barrier property of the formed thin film is significantly reduced. The pressure is 1 ×
If it is set to 10 ⁻⁵ (Torr) or less, the productivity is greatly reduced.

In the present invention, an active energy ray-curable composition containing a silane coupling agent having an acryloyl group or a methacryloyl group is applied on the metal oxide thin film thus formed, and then the active energy ray-curable composition is applied. The film is irradiated and cured to form a cured film. According to the study of the present inventors, when an active energy ray-curable composition containing a silane coupling agent having an acryloyl group or a methacryloyl group is used, the adhesion between the metal oxide thin film and the cured film is improved, and The gas barrier property is improved. Although the reason is not clear, the improvement in adhesion is due to the fact that the silane coupling agent chemically reacts with the metal oxide thin film and reacts with other film formations where acryloyl groups and methacryloyl groups of the silane coupling agent coexist. It is considered that the cured film is firmly bonded to the metal oxide thin film. In addition, the improvement in gas barrier properties is also attributable to the fact that the gap between metal oxide particles constituting the metal oxide thin film is filled with a silane coupling agent or a film-forming component that has reacted with the acryloyl group or methacryloyl group. Conceivable.

The silane coupling agent only needs to have at least one of an acryloyl group and a methacryloyl group, but preferably has an acryloyl group having a high reaction rate. For example, if a silane coupling agent having only an isocyanate group or a mercapto group as a reactive group and not having an acryloyl group or a methacryloyl group is used, the adhesion is not improved. This seems to be due to the fact that even though the bond between the silane coupling agent and the metal oxide thin film is formed, the silane coupling agent reacts with other co-existing film formations and is hardly taken into the film. It is.

The silane coupling agent having an acryloyl group or a methacryloyl group used in the present invention includes, for example, γ-acryloxypropyltrimethoxysilane,
Methacryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-acryloxypropylmethyldiethoxysilane, γ-methacryloxypropylmethyl Dimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxypropyl-tris (β-methoxyethoxy) silane, γ-methacryloxypropyl-tris (β-methoxyethoxy)
Examples include silane.

These silane coupling agents account for usually 0.1 to 60% by weight, preferably 0.2 to 45% by weight in the active energy ray-curable composition. If the amount of the silane coupling agent is too small, it is difficult for the adhesion between the cured film and the metal oxide thin film to be sufficiently exhibited. This is presumably because the amount of the functional group that reacts with the metal oxide thin film in the composition is not sufficient. Conversely, if the silane coupling agent is present in excess, the alkali resistance of the cured film may decrease. This is probably because a large amount of the silane coupling agent that does not react with the metal oxide thin film remains in the cured film and reacts with the alkali.

The active energy ray-curable composition comprises a conventional monomer, oligomer, polymer or the like which polymerizes by irradiation with an active energy ray to form a cured film, except for containing a silane coupling agent. For example, monomers or oligomers such as epoxy (meth) acrylate, urethane (meth) acrylate, and polyester (meth) acrylate are used. Examples of some of these include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexaacrylate. Monofunctional and polyfunctional acrylic monomers, methacrylic monomers, and vinyl monomers having one or more carbon-carbon double bonds, such as methacrylate, isoamyl acrylate, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, and N-vinylpyrrolidone. The active energy ray-curable composition may contain known additives such as an ultraviolet absorber and a thermal polymerization inhibitor.

In order to form a cured film with the active energy ray-curable composition, the active energy ray-curable composition is applied by various coating methods such as a gravure coating method, a reverse coating method, a die coating method and the like, and the active energy ray is applied. Irradiation and curing may be used. At this time, preheating may be performed after application and before curing. When the active energy ray-curable composition is diluted with a solvent, the solvent must be removed in this preheating step. The thickness of the cured film is usually preferably in the range of 0.5 to 200 μm. If the thickness of the cured film is less than 0.5 μm, application unevenness occurs, and the gas barrier properties and chemical resistance are not sufficiently improved. On the other hand, if the thickness of the cured film is greater than 200 μm, the adhesion will be poor.

The active energy rays to be irradiated are usually ultraviolet rays and electron beams. When these active energy rays are irradiated, radicals are generated in the composition and curing proceeds by a polymerization reaction. When ultraviolet rays are used as the active energy rays, usually, 3 to 5% by weight of a photopolymerization initiator is blended as a radical generation source. When an electron beam is used, it is not necessary to mix a photopolymerization initiator since radicals are generated in the composition molecules. The gas barrier film of the present invention as described above generally has excellent transparency, and in applications requiring a transparent film, the total light transmittance is preferably 80% or more, and particularly preferably. 85% or more.

[0019]

The present invention will be described more specifically with reference to the following examples and comparative examples, but the present invention is not limited to these examples. In the following examples, the thickness of the metal oxide thin film, oxygen permeability, moisture permeability, total light transmittance, adhesion, chemical resistance, and thickness of the cured film were measured as described below. Thickness of metal oxide thin film; electron microscope (Hitachi Ltd .; H
-600 type). Oxygen permeability; Oxygen permeability measuring device (trade name: OX-, manufactured by Modern Control Co., Ltd.) according to ASTM D-3985
TRAN100) at 25 ° C.-wet.

Moisture permeability: 40 ° C.-9 using a moisture permeability measuring device (trade name: Permatran-W1 manufactured by Modern Control Co.) according to ASTM F-1249.
It was measured under the condition of 0% RH. Total light transmittance: Measured using a spectrophotometer according to JIS K-7105.

Adhesion: According to JIS K-5400,
On the cured film composed of the active energy ray-curable composition,
A cross-cut cellophane tape peel test was performed. 1mm x 1mm
The following determination was made based on the number of squares remaining without being peeled out of the 100 squares. 100 pieces of squares remaining without peeling; ○ 〃 99-75; △ ７４ 74-0; ×

Chemical resistance: A 5% -NaOH aqueous solution is dropped on a cured film made of the active energy ray-curable composition, left for 10 minutes, and the surface state after wiping is visually observed or 400-fold differential interference. The following judgment was made by observing with a microscope. No erosion when observed with a differential interference microscope; ○ It is hard to see visually, but eroded when observed with a differential interference microscope; △ Eroded enough to be seen visually; × Thickness of cured film; JIS It measured using the electromagnetic-type film thickness gauge according to K-5400.

Further, as the metal oxide vapor-deposited film,
The one manufactured as follows was used. Silicon oxide deposited polyether sulfone film (PES
—SiO); polyether sulfone film (PES;
Manufactured by Mitsui Toatsu, trade name: TALPA1000, thickness 10
0 μm) and an isocyanate compound (manufactured by Nippon Polyurethane Industry Co., trade name; Coronate L) and a saturated polyester (manufactured by Toyobo Co., trade name; Byron 300) in a ratio of 1: 1.
Was coated with a coater and dried to form an anchor coat layer having a thickness of about 0.1 μm. Silicon oxide (SiO, manufactured by Sumitomo Citix Co.) was vapor-deposited on the anchor coat surface of the polyethersulfone film by a high-frequency induction heating method using a roll-up type vacuum vapor deposition apparatus under a vacuum of 8 × 10 ⁻⁵ Torr. Thus, a film having a silicon oxide thin film having a thickness of 350 ° was manufactured.

Aluminum oxide vapor deposited polyether monkey
Phone film (PES-Al_TwoO_Three); Instead of silicon oxide
Aluminum (Mitsubishi Chemical Corporation) and pressure 4
× 10 ^-FourWhile introducing oxygen gas so that it becomes Torr
The same procedure as described above was carried out except that vapor deposition was performed.
Aluminum oxide (Al_TwoO_Three) Fill with thin film
Manufactured. Silicon oxide deposited polyarylate film (PAR-Si
O); Polyant instead of polyethersulfone film
Rate film (PAR, manufactured by Kanegafuchi Chemical Co., Ltd., trade name: L
Same as above, except for using MEC AIF (thickness 75 μm).
In this manner, a filter having a silicon oxide thin film having a thickness of 350.degree.
Lum manufactured.

Examples 1 to 19 and Comparative Examples 1 to 2 On the metal oxide thin film of the film having the metal oxide thin film, a silane coupling agent and other coatings shown in Table 1 were formed, and Of photopolymerization initiator (manufactured by Ciba-Geigy Japan, trade name; IRGAC)
URE-184) is applied, and about 120 w / cm of a metal halide lamp is used.
It is cured by irradiating it with ultraviolet rays of 0 mJ / cm ² and has a thickness of 10
A cured film of μm was formed. Table 1 shows the physical properties of this film.
It is shown in FIG.

Comparative Example 3 The physical properties of the silicon oxide-deposited polyethersulfone film used in the examples are shown in Table 2. Comparative Example 4 A cured film of an ultraviolet curable composition was formed in the same manner as in Example 1, except that the polyether sulfone film before the anchor coat layer was provided. Table 2 shows the physical properties of this film. Comparative Example 5 Table 2 shows the physical properties of the silicon oxide-deposited polyarylate film used in the examples.

Comparative Example 6 A cured film of an ultraviolet-curable composition was formed in the same manner as in Example 1 except that the polyarylate film before the anchor coat layer was provided. Table 1 shows the physical properties of this film.
It is shown in FIG. Comparative Example 7 In Example 1, an ultraviolet-curable composition was applied to a surface (polyethersulfone surface) of a polyethersulfone film on which silicon oxide was vapor-deposited, opposite to the silicon oxide thin film surface. Except for the above, the procedure was exactly the same as in Example 1. Table 2 shows the results.

[0028]

[Table 1]

[0029]

[Table 2]

Description of reference numerals in Table 1 A: γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .; trade name: KBM503) B: γ-methacryloxypropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) Name: KBE503) C: γ-methacryloxypropylmethyldimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM502) D: γ-methacryloxypropyltris (β-methoxyethoxy) silane (manufactured by Nippon Unicar, trade name; A-1
75) E: γ-mercaptopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd .; trade name; KBM803) F: Epoxy acrylate (Shin-Nakamura Chemical Co., trade name;
NK oligo EA-1020) G: Trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd .; trade name: NK ester A-TMPT) H: Pentaerythritol triacrylate (manufactured by Kyoeisha Chemical Co., trade name; light acrylate PE-3A) I: Urethane acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name; NK Oligo U-340A)
X) J: isoamyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name; light acrylate 1A-A) K: pentaerythritol tetraacrylate (manufactured by Kyoeisha Chemical Co., trade name; light acrylate PE-4A)

[0031]

According to the present invention, the plastic film having a metal oxide thin film has (meth)
An active energy ray-curable composition containing a silane coupling agent having an acryloyl group is applied and cured by irradiating with an active energy ray, and the cured film has excellent adhesion and excellent gas barrier properties. And excellent in chemical resistance.

Claims (6)

[Claims] 1. An active energy ray-curable composition comprising a silane coupling agent having an acryloyl group and / or a methacryloyl group on a metal oxide thin film of a plastic film having a metal oxide thin film formed on a surface thereof. A gas barrier film, wherein a cured film of the above is formed. 2. The gas barrier film according to claim 1, wherein the active energy ray-curable composition contains a silane coupling agent in an amount of 0.2 to 45% by weight. 3. The gas barrier film according to claim 1, wherein an anchor coat layer having a thickness of 0.005 to 5 μm is interposed between the plastic film and the metal oxide thin film. 4. The metal oxide thin film has a thickness of 50 to 5000.
The gas barrier film according to any one of claims 1 to 3, wherein? 5. The gas barrier film according to claim 1, wherein the thickness of the cured film is 0.5 to 200 μm. 6. The gas barrier film according to claim 1, wherein the total light transmittance is 80% or more.