JPH09324061A - Gas-barrier film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a gas-barrier film which comprises a thermoplastic resin substrate and a coating layer formed on at least one side thereof and is excellent in gas-barrier propertied at a high humidity, adhesion between the substrate and the coating layer, and durability of the layer by forming it from a coating fluid contg. a specific inorg. layered compd. and a water-dispersible polymer. SOLUTION: A coating fluid is obtd. by dissolving dispersing 1-60wt.% inorg. layered compd. and 99-40wt.% water-soluble or -dispersible polymer in a solvent mixture comprising water and an alcohol in a wt. ratio of (99/1)-(20/80). The fluid is applied to at least one side of a thermoplastic resin substrate having a light transmission of 40% or higher, an Rt/Ra (a parameter of surface roughness) of 20 or lower, and a thickness of 2-100μm and is dried to form a coating layer having a thickness of 0.01-15μm and an Rt/Ra of 25 or lower.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a gas barrier film, and more particularly to a gas barrier film having excellent gas barrier properties under high humidity, adhesion to a substrate and durability of a coating film.

[0002]

2. Description of the Related Art In the field of packaging of foods and medicines, if oxygen or the like enters from the outside air, the contents cannot be stored for a long period of time due to deterioration of the contents. Therefore, a film having a gas barrier property capable of preventing entry of outside air. Is being developed.

Polymer engineering and
According to Science, Vol. 20, No. 22, pp. 1543-1546 (December 1986), polyvinylidene chloride, polyvinylidene chloride,
Examples include polyacrylonitrile and polyvinyl alcohol. However, since polyvinylidene chloride contains a chlorine atom and polyacrylonitrile contains a -CN group, environmental problems at the time of disposal have been raised in recent years. Further, since polyvinyl alcohol contains an -OH group, the humidity dependence of gas barrier properties is large, and the gas barrier properties are significantly reduced at high humidity. Even an ethylene-vinyl alcohol copolymer in which the humidity dependence of polyvinyl alcohol has been improved, gas barrier properties at high humidity are not yet sufficient.

On the other hand, silicon oxide (JP-B-53-12953)
And aluminum oxide (JP-A-62-1799).
A film in which an inorganic substance such as No. 35 is vapor-deposited on the surface of a substrate has been developed. However, the formation of these films involves a vapor deposition process, which results in extremely high costs, the lack of flexibility of the inorganic coating, and poor adhesion to the substrate due to poor adhesion to the substrate. There is a problem.

As means for solving these problems, a film in which a base material is provided with a coating film composed of a metal oxide and polyvinyl alcohol (JP-A-56-4563, etc.) has been developed. As for the gas barrier property at the time, it is not yet at a satisfactory level. Further, a film having a gas barrier layer composed of an inorganic layered compound and a high hydrogen bonding compound (JP-A-6-93133, JP-A-7-41)
However, there is a great disadvantage in terms of productivity because long time drying or heat treatment is required in the process of forming the gas barrier layer in order to obtain high barrier properties, and the adhesion between the coating material and the base material is also low. Low. If the adhesion to the base material is high, a highly reliable packaging material that does not break the bag or deform the bag when processed into a packaging bag or the like can be obtained.

[0006]

The object of the present invention is to solve the above-mentioned problems of the conventional gas barrier film, have a high gas barrier property even under high humidity, and have a high adhesion to a substrate and a coating film. It is to provide a gas barrier film having durability.

[0007]

In order to achieve the above object, the present invention provides an inorganic layered compound having a particle size of 200 nm or less and a water-soluble or water-dispersible polymer on at least one surface of a thermoplastic resin substrate. And a gas barrier film having a surface roughness parameter Rt / Ra of 25 or less.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention forms a coating film composed of an inorganic layered compound having a specific particle size and a water-soluble or water-dispersible polymer, and controls surface parameters of the coating film to control high humidity. We have developed a gas barrier film that has the following gas barrier properties, adhesion and durability, and are promising as a packaging material with high reliability in storage stability.

In the present invention, the particle size of the inorganic layered compound needs to be 200 nm or less in consideration of the gas barrier property under high humidity, the adhesion and the durability of the coating film. Preferably 100 nm or less, more preferably 50
nm or less.

The inorganic layered compound in the present invention is an inorganic compound in which extremely thin unit crystal layers are superposed to form one layered particle, and those which swell and cleave in a solvent are preferable. Among them, a clay compound having a swelling property in a solvent is particularly preferably used. The clay compound having a swelling property in a solvent in the present invention is a clay compound having a property of coordinating and absorbing water between ultra-thin unit crystal layers, and in general, Si ⁴⁺ is coordinated to O ^2−. The layers forming the tetrahedral structure and Al ³⁺ , Mg ²⁺ , Fe ²⁺ , Fe ³⁺ , Li ^+, etc. are O ^2−.
And a layer which forms an octahedral structure by coordinating to OH ⁻ are combined in a one-to-one or two-to-one structure and stacked to form a plate-shaped structure. But good. Typical ones are montmorillonite,
Beidellite, saponite, hectorite, kaolinite, halloysite, vermiculite, dickite,
Nacrite, antigorite, pyrophyllite, margarite, talc, tetrasilylic mica, muscovite,
Examples include phlogopite and chlorite. Among them, montmorillonite, beidellite, hectorite and saponite, which are called smectite group, are particularly preferably used.

The water-soluble or water-dispersible polymer in the present invention refers to a polymer which can be completely dissolved or finely dispersed in water at room temperature, and examples thereof include polyvinyl alcohol polymers or derivatives thereof, carboxymethyl cellulose, hydroxyethyl cellulose and the like. Cellulose derivatives, oxidized starch, etherified starch, starches such as dextrin, polyvinylpyrrolidone, copolymerized polyester containing polar groups such as sulfoisophthalic acid, vinyl polymers such as polyhydroxyethyl methacrylate or its copolymers, Examples include functional group-modified polymers such as an acrylic polymer, a urethane polymer, an ether polymer, or a carboxyl group, amino group, or methylol group of these various polymers. A polyvinyl alcohol polymer or a derivative thereof is preferable, and a polyvinyl alcohol having a saponification degree of 80 mol% or more is particularly preferable.
A copolymerized polyvinyl alcohol having a vinyl alcohol unit content of 60 mol% or more. The polymerization degree of the polyvinyl alcohol-based polymer or its derivative is preferably 100 to 5000, and more preferably 1200 to 2500.

In the present invention, defining the surface roughness parameter Rt / Ra of the coating film surface improves the abrasion resistance of the process when laminating an unstretched propylene film or the like with an adhesive interposed between them and improves the gas barrier property. Therefore, it is preferable. Rt is the maximum height, the distance between the maximum peak and the deepest valley of the surface roughness curve, and Ra is the center line average roughness. It is necessary that the surface roughness parameter Rt / Ra is 25 or less. More preferably, it is 20 or less. If the surface roughness parameter Rt / Ra exceeds 25, the gas barrier properties will decrease. This is considered to be because when the coating film was formed at a high speed, the coating film surface was shaved due to contact with a roll or contact between the films during winding. As a method of setting the surface roughness parameter Rt / Ra to 25 or less, a smooth thermoplastic resin substrate is coated with an inorganic layered compound and a water-soluble or water-dispersible polymer with a small ratio of the inorganic layered compound. A method of applying a coating material in a state of being uniformly dispersed in the agent and drying the coating material at a temperature of 160 ° C. or less for a short time within 20 seconds to form a coating film and the like are used. The details of the parameters are shown in "Measurement / Evaluation Method of Surface Roughness" by Jiro Nara (General Technology Center, 1983).

The mixing ratio of the inorganic layered compound / water-soluble or water-dispersible polymer in the present invention is 1/9 by weight.
The range of 9-60 / 40 is preferable, and 5 / 95-45 /
55 is more preferable. When it is less than 1/99, the gas barrier property under high humidity is deteriorated, and when it is more than 60/40, the adhesion and the durability of the coating film are deteriorated.

Further, in the present invention, it is preferable that the coating film contains 0.01 to 10% by weight of the crosslinking agent because the gas barrier property under high humidity is improved. More preferably, 0.
05 to 8%.

The cross-linking agent used in the present invention is not particularly limited as long as it has reactivity with a water-soluble or water-dispersible polymer. Preferably, an epoxy type crosslinking agent, an isocyanate type crosslinking agent, a melamine type crosslinking agent, an oxazoline type crosslinking agent, a silane coupling agent, etc. are preferably used.

Further, in the present invention, it is preferable that the coating film mainly composed of the inorganic layered compound and the water-soluble or water-dispersible polymer is oriented in at least one direction because the gas barrier property is improved. For orientation in at least one direction, an in-line coating method is preferably used. The state of orientation of the coating film is a known technique, for example, a refractive index method,
It can be analyzed using a total reflection infrared spectrum method, a total reflection Raman spectrum method, or the like.

The thickness of the coating film in the present invention is not particularly limited, but 0.01 from the viewpoint of the gas barrier film.
˜15 μm is preferable, and 0.1 to 10 μm is more preferable. 0.01-0.5 μm is more preferable for in-line coating, and 0.3-6 μm for off-line coating.
m is more preferred.

Further, the present invention is a film having a coating composed of an inorganic layered compound and a water-soluble or water-dispersible polymer as main constituents, and the main constituents are the inorganic layered compound and all the constituents of the coating film. It shows that the weight of the water-soluble or water-dispersible polymer is 70% or more. As long as the gas barrier properties and the transparency are not impaired, various additives may be contained in a weight ratio of 30% or less. The various additives include antioxidants, weathering agents, heat stabilizers, lubricants,
It is a crystal nucleating agent, an ultraviolet absorber, a coloring agent or the like. Further, as long as transparency and gas barrier properties are not impaired, inorganic or organic particles may be contained in a weight ratio of 20% or less. For example, calcium carbonate, titanium oxide, silicon oxide,
Examples include calcium fluoride, lithium fluoride, alumina, barium sulfate, zirconia, calcium phosphate, and crosslinked polystyrene particles.

Further, in order to enhance the interaction between the layered compound and the polymer, between the polymers or between the layered compounds in forming the coating film, a divalent or higher valent metal salt, a catalyst component or the like may be added. . It is desirable to use an acetate, a sulfate, a nitrate, or the like containing calcium, magnesium, aluminum, or the like because moisture resistance is improved. The amount is about 1 to 10000 ppm based on the coating film.

The thermoplastic resin substrate used in the present invention is necessary mainly for imparting mechanical properties and film processability, and includes various commercially available thermoplastic resin films. Although not particularly limited, typical examples include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate, nylon 6, and nylon 12
Such as polyamide, polyvinyl chloride, ethylene vinyl acetate copolymer or saponified product thereof, polystyrene, polycarbonate, polysulfone, polyphenylene oxide, polyphenylene sulfide, aromatic polyamide,
Polyimide, polyamide imide, cellulose, cellulose acetate, polyvinylidene chloride, polyacrylonitrile,
Polyvinyl alcohol and the like, and copolymers thereof. Polyesters such as polyethylene terephthalate and polyolefins such as polyethylene and polypropylene are preferred from the viewpoints of cost performance, transparency, gas barrier properties and the like.

These thermoplastic resin base materials may be unstretched, uniaxially stretched or biaxially stretched, but from the viewpoint of dimensional stability and mechanical properties, biaxially stretched ones are particularly preferable. The thermoplastic resin base material may contain various additives. For example, antioxidants, weathering agents, heat stabilizers, lubricants, nucleating agents, ultraviolet absorbers, coloring agents and the like.
Further, inorganic or organic particles may be contained as long as the transparency is not impaired. For example, talc, kaolinite, calcium carbonate, titanium oxide, silicon oxide, calcium fluoride, lithium fluoride, alumina, barium sulfate, zirconia, mica, calcium phosphate, crosslinked polystyrene particles, and the like. The average particle diameter is preferably 0.001 to 10 μm, more preferably 0.001 to 10 μm.
It is 3 to 5 μm. The average particle diameter is a particle diameter obtained by taking a photograph at a magnification of 10,000 to 100,000 using a transmission microscope or the like and calculating the number average.

Further, these thermoplastic resin substrates are preferably transparent. The light transmittance is preferably 40% or more, more preferably 60% or more. The thermoplastic resin substrate is preferably smooth. Rt / Ra is preferably 20 or less, more preferably 15 or less. The thickness of the thermoplastic resin substrate is not particularly limited, but is 2 to 100.
0 μm is preferred.

Next, a typical method for producing the gas barrier film of the present invention will be described.

The method for forming a coating film on a thermoplastic resin substrate is not particularly limited, and extrusion laminating method and melt coating method may be used, but coating is possible because high speed thin film coating is possible. It is preferable to apply a gravure coat, a reverse coat, a spray coat, a kiss coat, a die coat, an air knife coat or a metalling bar coat to a dispersion solution in which the constituent components of the film are dispersed in various solvents. Thermoplastic resin substrate is a known adhesion promoting treatment before application,
For example, a corona discharge treatment in air, a nitrogen gas, a mixed gas of nitrogen / carbon dioxide gas, or another atmosphere, a plasma treatment under reduced pressure, a flame treatment, an ultraviolet treatment, or the like may be performed. Of course, the anchor treatment may be performed using a known anchor treatment agent such as urethane resin, epoxy resin and polyethyleneimine.

When a biaxially stretched film of polyester such as polyethylene terephthalate or polyolefin such as polypropylene is used as the thermoplastic resin substrate, either off-line coating or in-line coating may be used. If an in-line coating is used, it is preferred to perform the coating before the film is heat set. The heat setting is to crystallize a film stretched by a known technique by heat-treating the film while holding the film at a temperature higher than the stretching temperature and lower than the melting point of the film. Therefore, before heat setting means before heat treatment, it is preferable to coat the film immediately after unstretching, immediately after uniaxial stretching in the longitudinal direction or transverse direction, and immediately after biaxial stretching. More preferably, it is a coating on a film immediately after uniaxial stretching, and it is particularly preferable that the film is further uniaxially stretched and thermally fixed.

The method for drying the coating film is not particularly limited, and a hot roll contact method, a heat medium (air, oil, etc.) contact method, an infrared heating method, a microwave heating method, and the like can be used. Drying of the coating film
From the viewpoint of gas barrier properties, it is preferably performed within the range of 60 ° C. to 180 ° C., and the drying time is 1 to 30.
Seconds, preferably 3 to 20 seconds.

The coating agent containing the constituents of the coating film is preferably a solution in which the inorganic layered compound is uniformly dispersed or swelled in the solvent and the water-soluble or water-dispersible polymer is uniformly dissolved or dispersed. As the solvent, water or a water / lower alcohol mixed solution is used, but it is preferable to use a water / lower alcohol mixed solution from the viewpoints of gas barrier properties under high humidity, adhesiveness of coating film and productivity. The lower alcohol is an alcoholic compound having a linear or branched aliphatic group having 1 to 3 carbon atoms. For example, methanol, ethanol, n- or iso-propanol is preferably used. The mixing ratio of water / alcohol is preferably from 99/1 to 20/80 by weight. Mixing ratio is 9
If it is greater than 9/1, there are problems such as insufficient gas barrier properties under high humidity, poor adhesion between the coating layer and the base material, and reduced productivity. The dispersibility in is deteriorated.

In order to impart coatability to the film, the mixed solvent may contain another water-soluble organic compound as the third component as long as the stability of the dispersion solution is maintained. Is also good. Examples of the water-soluble organic compound include alcohols such as methanol, ethanol, n- or iso-propanol, glycols such as ethylene glycol and propylene glycol, methyl cellosolve,
Glycol derivatives such as ethyl cellosolve and n-butyl cellosolve; polyhydric alcohols such as glycerin and wax; ethers such as dioxane; esters such as ethyl acetate; and ketones such as methyl ethyl ketone.
Further, the pH of the dispersion solution is from 2 to 11 in view of the stability of the solution.
Is preferred.

The method of preparing the coating agent is not particularly limited,
A method in which a water-soluble or water-dispersible polymer is uniformly dissolved in a solvent and then mixed with a solution in which a layered compound is uniformly dispersed is effectively used. In particular, the inorganic layered compound, because there is a possibility that secondary aggregation in the dispersion, after dispersing the layered compound in the solvent, a shearing force, a homomixer subjected to shear stress, a jet agitator, a ball mill, A method of uniformly dispersing by performing a mechanical forced dispersion treatment using a device such as a kneader, a sand mill, or a triple roll is preferably used. Furthermore, a cross-linking agent,
Particles or the like may be contained.

[0030]

[Evaluation method of characteristics] The evaluation method of characteristics used in the present invention is as follows.

(1) Particle size Centrifugal sedimentation type particle size distribution analyzer CA manufactured by Horiba, Ltd.
Using PA-700, the inorganic layered compound was dispersed in a solution having the same solvent composition as the coating agent used for forming the gas barrier coating film, and the temperature was measured at room temperature.

(2) Surface parameter The maximum height Rt and the center line average roughness Ra were measured using a high precision thin film step measuring instrument ET-10 manufactured by Kosaka Laboratory.
The measurement conditions were as follows, and the average value of 20 measurements was taken as a value, and the ratio of Rt to Ra was calculated.

Stylus tip radius: 0.5 μm Stylus load: 5 mg Measurement length: 1 mm Cutoff: 0.08 mm

(3) Gas barrier property Oxygen permeability measuring apparatus (OX-TRAN 2/20, manufactured by Modern Control Co., Ltd.) according to ASTM D-3985.
Was used to measure oxygen permeability. Measurement condition is temperature 23
° C and a relative humidity of 80%.

(4) Gas Barrier Property After Endurance Test A sample (250 mm × 180 mm) which has been subjected to 100 times of gelbo repetition (reciprocating motion cycle: 40 times / min) at 5 ° C. in a gelbo flex tester by the method described above. The gas barrier property was measured.

(5) Adhesion between coating film and base material Unstretched polypropylene film (CPP, T350 manufactured by Toray Synthetic Film Co., Ltd.) using a polyurethane adhesive.
1, 50 μm) and the coating surface of this film.
After standing at 0 ° C for 48 hours, reinforce each surface on the side opposite to the surface in contact with the adhesive with cellophane tape and cut to a width of 15 mm
Peeling of P and the film was carried out by 180 ° using Tensilon, and the peel strength at that time was obtained. The peeling was performed at a peeling speed of 10 cm / min, 25 ° C., and a relative humidity of 60%.

[0037]

【Example】

Example 1 Synthetic hectorite (manufactured by Nippon Silica Industry Co., Ltd., Laponite RDS) as an inorganic layered compound was dispersed in a water / isopropyl alcohol (hereinafter IPA) mixed solvent (weight ratio 90/10) in an amount of 3 wt% (A). liquid). When the particle size was measured in a mixed solvent, it was 35 nm. As a water-soluble or water-dispersible polymer, a saponification degree of 98.5 mol%,
Polyvinyl alcohol with a degree of polymerization of 1700 (hereinafter PVOH
Was abbreviated as 3 wt% in a water / IPA mixed solvent (weight ratio 90/10) (Liquid B). Liquids A and B were mixed so that the mixing ratio of the inorganic layered compound / water-soluble or water-dispersible polymer was 40/60 by weight, and IPA was 10% by weight based on the total amount of the coating material, and solid content. The coating material was prepared so that the concentration was 2.5%. The coating material was subjected to corona discharge treatment (treatment strength = 60 W · min / m ² ) in a 20 μm-thick corona discharge treated biaxially oriented polypropylene film (carbon dioxide gas / nitrogen mixed gas (volume ratio 83:17)). No. 11) with a reverse coater (coating speed 60 m / min), and then introduce it into a hot-air drying dryer under low tension 11
After drying at 0 ° C. for 10 seconds, the film was wound up. The characteristics of the obtained film are shown in Table 1. A film excellent in gas barrier property, gas barrier property after durability test, and adhesion was obtained.

Examples 2 to 4 Films were obtained in the same manner as in Example 1 except that the coating composition, coating thickness, and substrate were changed. The characteristics of the obtained film are shown in Table 1.

In Example 2, the composition of the coating film was changed, and a biaxially stretched polyester film (“Lumirror” manufactured by Toray Co., Ltd., thickness: 12 μm) subjected to corona discharge treatment (in air) was used as a substrate. When obtained in the same manner, a film excellent in gas barrier property, gas barrier property after durability test, and adhesion was obtained.

In Example 3, together with polyvinyl alcohol, a synthetic saponite having a particle diameter of 100 nm (Smecton SA, manufactured by Kunimine Industries Co., Ltd.) as an inorganic layered compound and a crosslinking agent (γ- (2-aminoethyl) aminopropyltrimethoxysilane) were used. When the coating film shown in Table 1 was obtained in the same manner as in Example 1, a film excellent in gas barrier property, gas barrier property after durability test, and adhesion was obtained.

In Example 4, as the water-soluble or water-dispersible polymer, PV having a saponification degree of 88.0 mol% and a polymerization degree of 500 was used.
When a coating film composition was changed using OH and a coating film was formed on the polyester film in the same manner as in Example 1, a film having excellent gas barrier properties was obtained.

Comparative Example 1 Synthetic mica having a particle size of 1 μm (tetrasilicic mica Na-Ts, manufactured by Topy Industries, Ltd.) as an inorganic layered compound, and a saponification degree of 8 as a water-soluble or water-dispersible polymer.
A film was obtained by using PVOH having a polymerization degree of 500 and 8.0 mol%. As is clear from Table 1, it was found that the film obtained was inferior in gas barrier property and adhesion after the durability test.

Comparative Example 2 A coating agent adjusted so that the weight ratio of the inorganic layered compound / water-soluble or water-dispersible polymer was 75/25 and the solid content concentration was 8 wt% was applied to PET, and the hot air dryer was used. In 1
After drying at 80 ° C. for 30 seconds, the surface roughness parameter is 27.
A film of 0 was obtained. It was found that the obtained film was significantly inferior in gas barrier property after the durability test.

Example 5 A coating material was prepared in the same manner as in Example 1 except that the composition ratio of the solid content of the coating material was changed to 5/95 (inorganic layered compound / water-soluble polymer) by weight.

Polyethylene terephthalate pellets (intrinsic viscosity 0.62 dl / g) containing 0.015% by weight of colloidal silica having an average particle size of 0.4 μm and 0.005% by weight of colloidal silica having an average particle size of 1.5 μm were used. After fully vacuum-dried, it is supplied to an extruder, melted at 285 ° C, extruded in a sheet form from a T-shaped die, and wound by a static casting cast method on a mirror-casting drum with a surface temperature of 25 ° C to be cooled and solidified. It was This unstretched film was heated to 95 ° C. and stretched 3.2 times in the longitudinal direction to obtain a uniaxially stretched film. This film was subjected to a corona discharge treatment in air, and the above-mentioned coating agent was applied to the treated surface by a bar coating method. The coated uniaxially stretched film is guided to a preheating zone while being gripped with clips, dried at 110 ° C. for 15 seconds, and then continuously stretched 3.2 times in a width direction in a 125 ° C. heating zone, and further heated at 230 ° C. Heat treatment was performed in the zone to obtain a film. The coating thickness of the obtained film was 0.3 μm. A film having excellent gas barrier properties, durability barrier properties, and adhesion was obtained.

Example 6 The solid content ratio of the coating composition was changed to 10/90 (inorganic layered compound / water-soluble polymer) by weight, and the saponification degree as a water-soluble or water-dispersible polymer was 88.0 mol%. A film was obtained in the same manner as in Example 5 except that PVOH having a degree of polymerization of 500 was used. A film having excellent gas barrier properties, durability barrier properties, and adhesion was obtained.

[0047]

[Table 1]

The abbreviations in the table have the following meanings.

PP is a biaxially oriented polypropylene film (thickness: 20 μm, nitrogen gas / carbon dioxide mixed gas (volume ratio 8
3:17) corona discharge treatment (treatment intensity = 60 W · mi
n / m ² )), PET is a biaxially stretched polyethylene terephthalate film (thickness 12 μm, corona discharge treated in air), PVOH 1 is saponification degree 98.5 mol%, polymerization degree 1
Polyvinyl alcohol of 700, PVOH2 has a saponification degree of 88.0 mol%, polymerization degree of 500, polyvinyl alcohol, a cross-linking agent is γ- (2-aminoethyl) aminopropyltrimethoxysilane, and particle 1 is a synthetic hectorite having a particle diameter of 35 nm ( Laponite RDS manufactured by Nippon Silica Industry,
Particle 2 is a synthetic saponite having a particle diameter of 100 nm (Sumikton SA, manufactured by Kunimine Industry), and particle 3 is a nano-TS made of tetrasilylic mycatopy, having a particle diameter of 1 μm.

[0050]

The film obtained by the present invention is not only excellent in gas barrier properties, but also has the adhesiveness and durability of the coating film, and thus can be used as any packaging material.

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Claims (9)

[Claims] 1. A film comprising a thermoplastic resin base material and a coating film having an inorganic layered compound having a particle size of 200 nm or less and a water-soluble or water-dispersible polymer as main constituent components formed on at least one surface of the thermoplastic resin base material. A gas barrier film having a surface roughness parameter Rt / Ra of 25 or less. 2. The gas barrier film according to claim 1, wherein the weight ratio of the inorganic layered compound to the water-soluble or water-dispersible polymer is 1/99 to 60/40. 3. The gas barrier film according to claim 1, wherein the weight ratio of the inorganic layered compound to the water-soluble or water-dispersible polymer is 5/95 to 45/55. 4. The particle size of the inorganic layered compound is 50 nm.
It is the following, The gas barrier film in any one of Claims 1-3. 5. The gas barrier film according to claim 1, wherein the water-soluble or water-dispersible polymer is a polyvinyl alcohol polymer or a derivative thereof. 6. The gas barrier film according to claim 1, wherein the coating film contains a cross-linking agent in an amount of 0.01 to 10% by weight with respect to the components of the coating film. 7. The gas barrier film according to claim 1, wherein the coating layer is oriented in at least one direction. 8. The gas barrier film according to claim 1, wherein the thermoplastic resin substrate is polyester. 9. The gas barrier film according to claim 1, wherein the thermoplastic resin substrate is made of an olefin resin.