JP2005035167A - Gas barrier film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas barrier film having a high gas barrier property even under a high humidity condition and capable of obtaining a high adhesion even when subjected to lamination.
A gas barrier layer composed of a water-soluble vinyl polymer and a swellable layered inorganic compound is formed on at least one surface of a substrate, and an arithmetic average roughness Ra of the gas barrier layer surface is 0.2 or less, squared A gas barrier film having an average square root roughness Rq of 0.2 or less and a ten-point average roughness Rzjis of 1.5 or less is prepared. The swellable layered inorganic compound may be composed of a smectite group clay mineral, or may be fine particles dispersed a plurality of times in a solvent at a treatment pressure of 20 MPa or more. The ratio (weight ratio) between the water-soluble vinyl polymer and the swellable layered inorganic compound is about the former / the latter = 99/1 to 70/30. The film has a peel strength of the gas barrier layer subjected to laminating to the laminate layer of 2 N / 15 mm or more, and a water vapor permeability of about 4 g / day / m ² or less in an atmosphere of 40 ° C. and 90% RH.
[Selection figure] None

Description

  The present invention relates to a gas barrier film having a high gas barrier property even under high humidity and a method for producing the same.

  Vinylidene chloride copolymer (PVDC) is known as a coating agent or film that exhibits high gas barrier properties against water vapor, oxygen, and the like, and is widely used as various packaging materials. However, in recent years, non-chlorine gas barrier coating agents and gas barrier films have been required due to environmental problems. Known non-chlorine oxygen barrier materials include polyacrylonitrile, polyvinyl alcohol (PVA), ethylene-vinyl acrylonitrile copolymer (EVOH), and the like.

  However, since polyacrylonitrile has a cyano group, it may have an adverse effect on the environment. PVA exhibits excellent gas barrier properties under low humidity, but the gas barrier properties are significantly reduced under high humidity. Furthermore, the ethylene-vinyl alcohol copolymer (EVOH) can reduce humidity dependency by copolymerizing hydrophobic ethylene with PVA, and the humidity resistance improves as the amount of ethylene introduced increases. , Oxygen barrier properties are reduced. Therefore, it is impossible to achieve both moisture resistance and gas barrier properties.

  Therefore, a method for improving the gas barrier property of a film even under high humidity by combining a water-soluble polymer such as PVA and layered inorganic compound particles has been proposed. For example, JP-A-9-324061 discloses a film in which a coating film composed of an inorganic layered compound having a particle size of 200 nm or less and a water-soluble or water-dispersible polymer is formed on at least one surface of a thermoplastic resin substrate. And the gas barrier film which made the surface roughness of the said coating-film surface into the specific range is disclosed. This document describes that the ratio (weight ratio) between the inorganic layered compound and the water-soluble polymer is the former / the latter = 1/99 to 60/40, preferably about 5/95 to 45/55. Yes. However, in this film, the adhesion between the substrate and the coating film is low, and the gas barrier property is not sufficient.

  Japanese Patent Laid-Open No. 2002-331618 discloses a film in which a coating film composed of a water-soluble polymer and inorganic layered particles is formed on at least one surface of a thermoplastic resin substrate, and the surface of the coating film surface A gas barrier film having a roughness in a specific range is disclosed. This document also describes that the surface of the base material is anchored with a urethane resin or the like before the coating film is formed on the base material. However, even with this film, the adhesion between the substrate and the coating film is low.

Further, when these gas barrier films are subjected to extrusion lamination, sufficient peel strength cannot be obtained.
JP-A-9-324061 JP 2002-331618 A

  Accordingly, an object of the present invention is to provide a gas barrier film that has a high gas barrier property even under high humidity conditions and can provide a high adhesion even when subjected to lamination.

  Another object of the present invention is to provide a gas barrier film capable of obtaining high adhesion even when subjected to extrusion lamination.

  Still another object of the present invention is to provide a gas barrier film having a low environmental load and high transparency.

  As a result of intensive investigations to achieve the above-mentioned problems, the present inventors have found that a gas barrier containing a water-soluble vinyl polymer and a swellable layered inorganic compound on a substrate and having a two-dimensional surface roughness in a specific range. It has been found that when the layer is provided, it has high gas barrier properties under high humidity conditions, and high adhesion can be obtained even when it is subjected to extrusion lamination, thereby completing the present invention.

That is, the gas barrier film of the present invention is a film in which a gas barrier layer composed of a water-soluble vinyl polymer and a swellable layered inorganic compound is formed on at least one surface of a substrate, and the surface of the gas barrier layer The arithmetic average roughness Ra is 0.2 or less, the root mean square roughness Rq is 0.2 or less, and the ten-point average roughness Rzjis is 1.5 or less. The swellable layered inorganic compound may be composed of a smectite group clay mineral such as montmorillonite, or may be fine particles that have been dispersed multiple times in a solution at a treatment pressure of 20 MPa or more. The ratio (weight ratio) between the water-soluble vinyl polymer and the swellable layered inorganic compound is about the former / the latter = 99/1 to 70/30 (particularly 99/1 to 80/20). The water-soluble vinyl polymer may be composed of polyvinyl alcohol having a saponification degree of 96 mol% or more and a polymerization degree of 200 or more. The thickness of the gas barrier layer is about 0.2 to 2 μm. In the film, an adhesive layer may be interposed between the base material and the gas barrier layer. The film has a peel strength of the gas barrier layer subjected to laminating to the laminate layer of about 2 N / 15 mm or more, and has a water vapor permeability of about 4 g / day / m ² or less in a 40 ° C., 90% RH atmosphere, The haze is about 10% or less.

  The present invention is a method for producing the film, wherein a gas barrier layer is formed by applying a coating liquid containing a water-soluble vinyl polymer and a swellable layered inorganic compound to at least one surface of a substrate, As the swellable layered inorganic compound, a method of using fine particles dispersed in a plurality of times at a treatment pressure of 20 MPa or more in a solution is also included.

Further, the present invention is a laminate in which a laminate layer is further laminated on the gas barrier layer of the gas barrier film via a laminate adhesive layer, and the coating amount of the laminate adhesive layer is 0.005. Laminates that are ˜5 g / m ² are also included.

  Furthermore, the present invention also includes a method for producing a laminate by forming a laminating adhesive layer on the gas barrier layer of the gas barrier film and further laminating (particularly extrusion laminating) the laminating layer on the laminating adhesive layer. included.

  In the present invention, since a gas barrier layer containing a swellable layered inorganic compound and having a surface roughness within a specific range is formed on a substrate, it has a high gas barrier property even under high humidity conditions and is used for lamination. Even high adhesion can be obtained. In particular, even when subjected to extrusion lamination, high adhesion can be obtained. Furthermore, since the gas barrier film of the present invention has a low environmental load and high transparency, it is suitable for food packaging materials and the like.

  In the gas barrier film of the present invention, a gas barrier layer composed of a water-soluble vinyl polymer and a swellable layered inorganic compound is formed on at least one surface of a substrate. Furthermore, an adhesive layer may be interposed between the base material and the gas barrier layer.

[Base material]
The type of substrate is not particularly limited, and examples thereof include papers and plastic films. Examples of plastics constituting the films include olefin resins, polyester resins (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate). Homo or copolyalkylene arylates such as phthalates, liquid crystalline polyesters, etc., polyamide resins (nylon 6, nylon 66 etc.), styrene resins (polystyrene, acrylonitrile-styrene copolymers etc.), vinyl chloride resins (polyvinyl chloride) Etc.), polycarbonate resins, cellulose ester resins and the like. The substrate may be a single substrate or a composite substrate composed of a plurality of layers (for example, a laminated paper of paper and plastic, a laminate of a plastic film and an aluminum foil, etc.) Good. Among these base materials, there are base materials composed of olefin resins, aromatic polyesters (poly C _2-4 alkylene arylates or copolyesters), polyamides, particularly olefin resins, in terms of transparency and moisture resistance. preferable.

Examples of the olefin resin include olefin homo- or copolymers. Examples of the olefin include α-C _2-16 olefins such as ethylene, propylene, 1-butene, isobutene, 4-methyl-1-butene, 1-pentene, 3-methyl-1-pentene and 1-hexene. Can be mentioned. These olefins may be used alone or in combination of two or more. Of these olefins, α-C _2-8 olefins, more preferably α-C _2-4 olefins (ethylene, propylene, etc.), particularly at least propylene are preferable.

The olefin resin may be a copolymer of an olefin and a copolymerizable monomer. Examples of the copolymerizable monomer include (meth) acrylic acid ester [for example, (meth) acrylic acid C _1-6 alkyl ester]; vinyl esters (for example, vinyl acetate); cyclic olefins (norbornene, ethylidene norbornene) And cyclopentadiene); dienes and the like. A copolymerizable monomer can be used individually or in combination of 2 or more types. The usage-amount of a copolymerizable monomer can be selected from the range of 0-100 weight part with respect to 100 weight part of olefins, Preferably it is 0-50 weight part, More preferably, it is about 0-25 weight part.

  Examples of the olefin resin include polyethylene resins [for example, low, medium or high density polyethylene, linear low density polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-propylene-butene. -1 copolymer, ethylene- (4-methylpentene-1) copolymer, etc.], polypropylene resin (eg, polypropylene, propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-ethylene- And propylene-containing resins containing 80% by weight or more of propylene such as butene-1 copolymer) and poly (methylpentene-1) resins. Examples of the copolymer include ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer or its ionomer, ethylene- (meth) acrylate copolymer such as ethylene-ethyl acrylate copolymer, Examples thereof include maleic anhydride grafted polypropylene.

  The copolymer (a copolymer of olefins and a copolymer of an olefin and a copolymerizable monomer) includes a random copolymer, a block copolymer, or a graft copolymer.

  Of these olefin resins, polypropylene resins are preferable from the viewpoints of heat resistance, oil resistance, strength, rigidity, and the like. The polypropylene resin contains a propylene homopolymer or a propylene-α-olefin copolymer, and the ratio (weight ratio) of propylene and α-olefin is propylene / α-olefin = 60/40 to 100/0, preferably It is about 70/30 to 100/0, more preferably about 80/20 to 100/0 (particularly 90/10 to 100/0). When the proportion of α-olefin exceeds 40% by weight, rigidity and heat resistance are lowered.

  The polypropylene resin may have an atactic structure, but may have stereoregularity such as an isotactic, syndiotactic, or metallocene structure generated by a metallocene catalyst. Among these, a polypropylene resin having an isotactic structure is preferable from the viewpoint of simplicity and economy.

  The substrate may be unstretched or stretched (uniaxial or biaxial), and can be appropriately selected depending on the method for producing a gas barrier film. For example, when a gas barrier layer is coated on a substrate, a biaxially stretched film may be used, and when extrusion lamination is performed, an unstretched film may be used. Moreover, in order to improve the adhesiveness, the surface of the substrate may be subjected to a surface treatment such as a discharge treatment such as corona discharge or glow discharge, an acid treatment or a wrinkle treatment.

  The base material may contain one or more resins selected from petroleum resins and terpene resins for the purpose of improving water vapor barrier properties.

  Examples of the petroleum resin include resins made mainly of cyclopentadiene or higher olefin hydrocarbons, or hydrogenated products thereof (for example, resins hydrogenated at a hydrogenation rate of 80% or more). These petroleum resins preferably do not contain polar groups. Specific examples of such petroleum resin include trade name “Arcon P-125” manufactured by Arakawa Chemical Co., Ltd., “Escollet 5320HC” manufactured by Tonex Co., Ltd., and the like.

  As the terpene resin, for example, pinene, carene, myrcene, osimene, limonene, terpinolene, terpinene, sabinene, tricyclene, pisapolene, gingiperene, santalen, camphorene, mylene, totalene, or hydrogenated products thereof (for example, 80% or more A resin hydrogenated at a hydrogenation rate). These terpene resins preferably do not contain polar groups.

  For base materials, stabilizers (antioxidants, UV absorbers, light stabilizers, heat stabilizers, etc.), flame retardants, flame retardant aids, fillers, plasticizers, impact resistance improvement as necessary Agents, reinforcing agents, colorants, dispersants, antistatic agents, foaming agents, antibacterial agents and the like may be added. These additives can be used alone or in combination of two or more.

  The thickness of the substrate is about 5 to 100 μm, preferably about 10 to 70 μm, and more preferably about 15 to 50 μm.

[Adhesive layer]
The gas barrier layer may be formed directly on the substrate, but is usually formed via an adhesive layer. Examples of the adhesive component (for example, adhesive resin) constituting the adhesive layer include urethane-based resins (such as isocyanate group-containing polymers), epoxy resins (such as bisphenol A type epoxy resins), and amino group-containing polymers (such as nylon 11 and nylon). 12), imino group-containing polymer (polyalkyleneimine such as polyethyleneimine), polyester resin (aliphatic polyester resin, aromatic copolyester resin, etc.), olefin resin (maleic anhydride grafted polypropylene) And modified polyolefins such as ethylene- (meth) acrylic acid copolymers), rubber adhesives (rubber-modified styrene resins such as ABS resins), coupling agents [titanium coupling agents (eg, tetraisopropyl titanate) And titanate Such as titanium alkoxide or polymer thereof such as butyl), a silane coupling agent], and the like. These adhesive components can be used alone or in combination of two or more. Of these adhesive components, polyester resins, urethane resins, epoxy group-containing polymers, amino group-containing polymers, and the like are preferable.

  The adhesive layer may contain the same additive as the base material.

  The thickness of the adhesive layer is about 0.01 to 3 μm, preferably about 0.01 to 2 μm, and more preferably about 0.01 to 1 μm.

[Gas barrier layer]
The water-soluble vinyl polymer constituting the gas barrier layer includes a vinyl alcohol polymer and the like. Examples of the vinyl alcohol polymer include homopolymers such as polyvinyl alcohol, and C _2-3 olefin-vinyl alcohol copolymers such as ethylene-vinyl alcohol copolymers. These water-soluble vinyl polymers can be used alone or in combination of two or more. Of these, from the viewpoint of gas barrier properties, polyvinyl alcohol and ethylene-vinyl alcohol copolymers having a low ethylene content (for example, ethylene content of 30 mol% or less, preferably 10 mol% or less), particularly polyvinyl alcohol are preferred.

  The saponification degree of the vinyl alcohol polymer (especially polyvinyl alcohol) can be selected from the range of 80 mol% or more, preferably 96 mol% or more, more preferably 99 mol% or more (particularly 99.5 mol% or more). Degree. The degree of polymerization of the vinyl alcohol polymer (particularly the vinyl alcohol polymer) is, for example, 200 or more (for example, 200 to 5000), preferably 400 to 5000, and more preferably about 500 to 3000.

  The swellable layered inorganic compound is an inorganic compound having a structure in which unit crystal layers are laminated and exhibiting a property of swelling or cleaving by coordinating or absorbing a solvent (particularly water) between the layers. Examples of such inorganic compounds include swellable hydrous silicates, for example, smectite group clay minerals (montmorillonite, beidellite, nontronite, saponite, hectorite, soconite, stevensite, etc.), vermiculite group clay minerals (vermiculite, etc.) , Kaolin-type minerals (eg halloysite, kaolinite, enderite, dickite), phyllosilicates (eg talc, pyrophyllite, mica, margarite, muscovite, phlogopite, tetrasilic mica, teniolite), jamonite group Examples thereof include minerals (such as antigolite) and chlorite group minerals (such as chlorite, cookite, and nanthite). These swellable layered inorganic compounds may be natural or synthetic. These layered inorganic compounds can be used alone or in combination of two or more. Of these swollen layered inorganic compounds, smectite group clay minerals, particularly montmorillonite, are preferred.

  The swellable layered inorganic compound is preferably finely divided from the viewpoint of achieving both gas barrier properties and adhesion between the substrate and the gas barrier layer. The swellable layered inorganic compound that has been microparticulated is usually plate-shaped or flat-shaped, and the planar shape is not particularly limited, and may be an amorphous shape. The average particle diameter (planar average particle diameter) of the swellable layered inorganic compound that has been microparticulated is, for example, 0.01 to 5 μm, preferably 0.1 to 3 μm, and more preferably about 0.5 to 2 μm. is there. The concentration of the inorganic compound is, for example, about 0.5 to 20% by weight, preferably about 1 to 10% by weight, and more preferably about 2 to 5% by weight.

  The fine particle treatment is preferably performed by high-pressure dispersion treatment in a solution. Examples of the solvent include water or water-soluble solvents (lower alcohols such as methanol and ethanol, acetone and the like), and water is usually used.

The treatment pressure in the high-pressure dispersion treatment is, for example, 20 MPa (about 200 kgf / cm ² ) or more (for example, 20 to 100 MPa), preferably about 20 to 80 MPa, and more preferably about 40 to 60 MPa. Examples of the treatment method include a method in which a swellable layered inorganic compound is swollen in a solvent and then stirred at the above-mentioned pressure with a high-pressure homogenizer to perform high-pressure dispersion. Such high-pressure dispersion treatment is performed a plurality of times (for example, 2 to 10 times), preferably 2 to 7 times, more preferably about 2 to 5 times.

  The ratio (weight ratio) between the water-soluble vinyl polymer and the swellable layered inorganic compound is the former / the latter = 99/1 to 70/30, preferably 98/2 to 75/25, more preferably 95/5 to 80. / 20 or so. When the ratio of both is in this range, the adhesion between the substrate and the gas barrier layer is high.

  The surface of the gas barrier layer is preferably smooth from the viewpoint of improving the adhesiveness to the substrate, in particular, even when subjected to lamination such as extrusion lamination. In the present invention, according to JIS B 0601, the arithmetic average roughness Ra, the root mean square roughness Rq, and the ten-point average roughness Rzjis on the surface of the gas barrier layer are required to be in specific ranges, respectively. When each of Ra, Rq, and Rzjis is used alone, there is not much correlation with the laminate strength, and the laminate strength is improved by limiting the three types simultaneously.

  Specifically, Ra is 0.2 or less (for example, 0.01 to 0.2), preferably 0.05 to 0.15, and more preferably about 0.1 to 0.12. Rq is 0.2 or less (for example, 0.01 to 0.2), more preferably 0.05 to 0.17, and still more preferably about 0.1 to 0.16. Rzjis is 1.5 or less (for example, 0.1 to 1.5), preferably 0.3 to 0.95, and more preferably about 0.5 to 0.9.

  The gas barrier layer may contain the same additive as the base material.

  The thickness of a gas barrier layer can be selected from the range of about 0.2-5 micrometers, for example, 0.2-2 micrometers, Preferably it is 0.3-3 micrometers, More preferably, it is about 0.5-2 micrometers.

[Gas barrier film]
The total thickness of the gas barrier film is, for example, about 5 to 200 μm, preferably about 10 to 100 μm.

  The gas barrier film of the present invention has high adhesion between the substrate and the gas barrier layer. Further, even when this film is subjected to a laminate layer and a laminate composed of an olefin resin, the adhesion of the gas barrier layer to the laminate layer is high, and the peel strength between the laminate layer and the gas barrier layer is, for example, 2 N / 15 mm or more (for example, 3 to 10 N / 15 mm), preferably 3.5 N / 15 mm or more (for example, 3.5 to 10 N / 15 mm), more preferably about 4 N / 15 mm or more (for example, 4 to 10 N / 15 mm). is there. In particular, even when it is subjected to extrusion lamination, the adhesion between the laminate layer and the gas barrier layer is high, and the peel strength in such a range is exhibited.

The gas barrier film is excellent in gas barrier properties. For example, the water vapor permeability in an atmosphere of 40 ° C. and 90% RH is 4 g / day / m ² or less (for example, 0.1 to 3.5 g / day / m ^2). ), preferably from 3.2g / day / m ² or less ^{(e.g., 0.1~3.2g / day / m 2)} , more preferably 3g / day / m ² or less (e.g., 0.1 to 3 g / day / M ² ).

  The gas barrier film is also excellent in transparency. For example, the haze is 10% or less (for example, 1 to 10%), preferably 9% or less (for example, 1 to 9%), more preferably 8% or less (for example, 1-8%).

[Method for producing gas barrier film]
The method for producing the gas barrier film of the present invention is not particularly limited. For example, after applying a coating solution containing an adhesive component as necessary to at least one surface of the substrate, the water-soluble vinyl polymer and the fine particles are applied. Examples include a coating method in which a gas barrier layer is formed by applying an aqueous coating solution containing a swellable layered inorganic compound. The coating solution may be prepared by mixing with an appropriate solvent (such as a water-soluble solvent or a water-insoluble solvent).

[Laminate]
In the laminate of the present invention, a laminate layer is further laminated on the gas barrier layer of the gas barrier film via a laminating adhesive layer. As the laminate layer, for example, papers and plastic films exemplified in the section of the substrate can be used. Among these, in order to impart heat sealability, etc., olefin resins (polyethylene resins, ethylene-ethyl adipate copolymers, ethylene- (meth) acrylic acid copolymers or ionomers, amorphous polypropylene resins, etc.) ) Can be preferably used. The thickness of the laminate layer is not particularly limited, but is about 5 to 100 μm, preferably about 10 to 70 μm.

  As the adhesive layer for laminating, the adhesive components exemplified in the paragraph of the adhesive layer can be used. When used for extrusion lamination, among the adhesive components, urethane resin, imino group-containing polymer, butadiene-based polymer, coupling agent, particularly urethane resin, imino group-containing polymer (polyalkyleneimine such as polyethyleneimine), Butadiene polymers (epoxidized polybutadiene, maleic acid-modified polybutadiene, etc.) are preferred. Urethane resins include, for example, isocyanate group-containing prepolymers [diol components (polyester diols obtained from aliphatic diol components such as ethylene glycol and 1,4-butanediol, and dicarboxylic acids such as adipic acid) and the like, and A diisocyanate component (an aromatic diisocyanate such as tolylene diisocyanate, an alicyclic diisocyanate such as isophorone diisocyanate, an aliphatic diisocyanate such as hexamethylene diisocyanate) and the like, and a polyol component ( A two-component curable urethane resin composed of the diol component and the like.

  The laminating adhesive layer may contain the same additive as that of the substrate.

[Manufacturing method of laminate]
The laminate can be obtained by forming a laminating adhesive layer on the gas barrier layer of the gas barrier film and further laminating a laminating layer composed of an olefin resin on the laminating adhesive layer. The laminating method may be a dry laminating method in which a previously prepared laminating layer is bonded, or an extrusion laminating method in which the laminating layer is melt-extruded. Even if the laminate of the present invention is laminated by an extrusion laminating method, it has high peel strength as described above.

The adhesive layer for laminating can be formed by a method of coating a coating solution containing an adhesive component, similarly to the adhesive layer. The application amount of the adhesive layer for laminating is, for example, 0.005 to 5 g / m ² , preferably 0.005 to 4 g / m ² , and more preferably about 0.005 to 3 g / m ^{2 in} terms of dry weight.

  As an extrusion method in the extrusion laminating method, an extrusion method such as an extrusion method (a method using a flat shape or a T-shaped die) can be used.

  Since the gas barrier film and laminate of the present invention have the above-mentioned properties, they are useful as packaging materials for various packaging films, particularly foods that are susceptible to quality deterioration due to water vapor or oxygen.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In addition, the evaluation method of the physical property of the film obtained by the Example and the comparative example is as follows.

[Surface roughness]
The obtained film was cut into a length of 10 cm and a width of 2 cm and fixed on a glass plate so as not to sag, and then a surface roughness shape measuring device for gas barrier layer (manufactured by Tokyo Seimitsu Co., Ltd., Surfcom 1400A) was used. The surface roughness was measured.

[Haze]
It measured according to JIS K7105 method.

[Adhesion with laminate layer]
(Peel strength of dry laminate film)
The ratio of TM220 / CAT58 = 7.63 / 1.15 (weight ratio in terms of solid content) as a two-component curing type polyurethane adhesive for laminate (manufactured by Toyo Morton Co., Ltd., “TM220” and “CAT58”) The mixture was mixed in ethyl acetate at 2.5 g / m ² on the gas barrier layer surfaces of the gas barrier films obtained in Examples 1 and 2 and Comparative Examples 1 to 5 and dried. Tocello Co., Ltd. product, TUX-Tcs) was crimped and laminated. This film was stored at 40 ° C. and 30% RH for 24 hours, and then cut into strips with a width of 15 mm to prepare test pieces. The peel strength of this test piece was measured according to JIS K 7127 as follows. That is, the base material of the test piece and the unstretched polyethylene film (laminate layer) were respectively held, and the base material and the unstretched polyethylene film were peeled 180 ° at a rate of 300 mm / min, and the peel strength was measured.

(Peel strength of extruded laminate film)
The peel strength was measured in the same manner using the extruded laminate films obtained in Examples 3 to 4 and Comparative Examples 1 to 5 instead of the dry laminated film.

[Water vapor transmission rate]
The obtained film was cut into a predetermined size, and the water vapor transmission rate was measured under the conditions of a temperature of 40 ° C. and a relative humidity of 90% RH with a water vapor transmission rate measuring device (manufactured by MOCON, PERMATRAN W200). . The biaxially oriented polypropylene film surface side at the time of measurement is set to 0% humidity.

Example 1
Montmorillonite (Kunimine Kogyo Co., Ltd., Kunipia RG) is used as a swellable inorganic layered silicate in a water solution using a high-pressure disperser (Niro Soavi, high-pressure homogenizer, processing pressure 50 MPa). The solution was dispersed at high pressure and a 4% by weight aqueous solution of montmorillonite was prepared. Polyvinyl alcohol (hereinafter referred to as PVA) (manufactured by Kuraray Co., Ltd., RS4104) aqueous solution is added to this montmorillonite aqueous solution, and in terms of solid content, PVA (A) / montmorillonite (B) = 90/10 (weight ratio). A coating solution was prepared as follows.

  On the other hand, using a biaxially stretched polypropylene film subjected to corona discharge treatment (Daicel Chemical Industries, Ltd., W1H, count 20), a polyester adhesive diluted with methyl ethyl ketone (Toyobo Co., Ltd., Byron 30SS) is dried. After coating so that the subsequent film thickness was 0.3 μm, the film was dried at 80 ° C. for 30 seconds. On this adhesive layer, the prepared PVA / montmorillonite coating solution was applied so that the film thickness after drying was 1 μm and then dried at 100 ° C. for 1 minute to obtain a gas barrier film. The results of evaluating the characteristics of the obtained film are shown in Table 1.

Example 2
Montmorillonite (Kunimine Kogyo Co., Ltd., Kunipia RG) is used as a swellable inorganic layered silicate in a water solution using a high-pressure disperser (Niro Soavi, high-pressure homogenizer, processing pressure 50 MPa). The solution was dispersed at high pressure and a 4 wt% aqueous solution was prepared. An aqueous solution of PVA (manufactured by Kuraray Co., Ltd., RS4104) was added to this aqueous solution of montmorillonite, and a coating solution was prepared so that PVA (A) / montmorillonite (B) = 80/20 (weight ratio) in terms of solid content. .

  On the other hand, using a biaxially stretched polypropylene film subjected to corona discharge treatment (manufactured by Daicel Chemical Industries, Ltd., W1H, count 20), a polyester adhesive diluted with methyl ethyl ketone (byron 30SS, manufactured by Toyobo Co., Ltd.) After coating so that the film thickness after drying was 0.3 μm, it was dried at 80 ° C. for 30 seconds. A PVA / montmorillonite coating solution prepared on this adhesive layer was applied so that the film thickness after drying was 1 μm and then dried at 100 ° C. for 1 minute to obtain a gas barrier film. The results of evaluating the characteristics of the obtained film are shown in Table 1.

Example 3
On the surface of the gas barrier layer of the film obtained in Example 1, as a laminating adhesive layer, a two-component curable polyurethane laminating adhesive (“EL-530A” and “EL-530B” manufactured by Toyo Morton Co., Ltd.) Were mixed in ethyl acetate at a ratio of EL-530A / EL-530B = 1/1 (weight ratio in terms of solid content) and coated at 0.2 g / m ² (dry weight). Furthermore, extrusion lamination was performed by extruding polyethylene melted at 320 ° C. onto the coated surface and pressure bonding to obtain a gas barrier film. The results of evaluating the characteristics of the obtained film are shown in Table 1.

Example 4
On the gas barrier layer surface of the film obtained in Example 2, as a laminating adhesive layer, a two-pack curable polyurethane laminating adhesive ("EL-530A" and "EL-530B" manufactured by Toyo Morton Co., Ltd.) Were mixed in ethyl acetate at a ratio of EL-530A / EL-530B = 1/1 (weight ratio in terms of solid content) and coated at 0.2 g / m ² (dry weight). Furthermore, extrusion lamination was performed by extruding polyethylene melted at 320 ° C. onto the coated surface and pressure bonding to obtain a gas barrier film. The results of evaluating the characteristics of the obtained film are shown in Table 1.

Comparative Example 1
Using montmorillonite (Kuniminee Co., Ltd., Kunipia RG) as a swellable inorganic layered silicate, high-pressure dispersion twice using a high-pressure disperser (Niro Soavi, high-pressure homogenizer, treatment pressure 50 MPa) A 4 wt% aqueous solution was prepared. An aqueous solution of PVA (manufactured by Kuraray Co., Ltd., RS4104) was added to this aqueous solution of montmorillonite, and a coating solution was prepared so that PVA (A) / montmorillonite (B) = 65/35 in terms of solid content.

  On the other hand, using a biaxially stretched polypropylene film subjected to corona discharge treatment (Daicel Chemical Industries, Ltd., W1H, count 20), a polyester adhesive diluted with methyl ethyl ketone (Toyobo Co., Ltd., Byron 30SS) is dried. After coating so that the subsequent film thickness was 0.3 μm, the film was dried at 80 ° C. for 30 seconds. A PVA / montmorillonite aqueous solution prepared on this adhesive layer was applied so that the film thickness became 1 μm after drying, and then dried at 100 ° C. for 1 minute to obtain a gas barrier film. The results of evaluating the characteristics of the obtained film are shown in Table 1.

Comparative Example 2
One-time high-pressure dispersion using montmorillonite (Kunimine Kogyo Co., Ltd., Kunipia RG) as a swellable inorganic layered silicate, using a high-pressure disperser (Niro Soavi, high-pressure homogenizer, processing pressure 50 MPa) A 4 wt% aqueous solution was prepared. A PVA (Kuraray Co., Ltd., RS4104) aqueous solution was added to this montmorillonite aqueous solution, and a coating solution was prepared so that PVA (A) / montmorillonite (B) = 80/20 in terms of solid content.

  Using a biaxially stretched polypropylene film subjected to corona discharge treatment (manufactured by Daicel Chemical Industries, Ltd., W1H, count 20), a polyester adhesive diluted with methyl ethyl ketone (manufactured by Toyobo Co., Ltd., Byron 30SS) is dried. After coating to a film thickness of 0.3 μm, it was dried at 80 ° C. for 30 seconds. A PVA / montmorillonite aqueous solution prepared on this adhesive layer was applied so that the film thickness after drying was 1 μm and then dried at 100 ° C. for 1 minute to obtain a gas barrier film. The results of evaluating the characteristics of the obtained film are shown in Table 1.

Comparative Example 3
Using a biaxially stretched polypropylene film (G1, count 20 manufactured by Daicel Chemical Industries, Ltd.) subjected to corona discharge treatment, a polyester adhesive diluted with methyl ethyl ketone (byron 30SS manufactured by Toyobo Co., Ltd.) is dried. After coating to a film thickness of 0.3 μm, it was dried at 80 ° C. for 30 seconds. An aqueous solution of PVA (manufactured by Kuraray Co., Ltd., RS4104) was applied onto the adhesive layer so that the film thickness after drying was 1 μm, and then dried at 100 ° C. for 1 minute to obtain a gas barrier film. The results of evaluating the characteristics of the obtained film are shown in Table 1.

Comparative Example 4
As a swellable inorganic layered silicate, a montmorillonite (NTOP-8 manufactured by Topy Industries, Ltd.) having an aspect ratio different from that of Examples 1 and 2, a high-pressure disperser (manufactured by Niro Soavi), a high-pressure homogenizer, Using a treatment pressure of 50 MPa), high-pressure dispersion was performed twice to prepare a 4 wt% aqueous solution. A PVA (Kuraray Co., Ltd., RS4104) aqueous solution was added to this montmorillonite aqueous solution, and a coating solution was prepared so that PVA (A) / montmorillonite (B) = 80/20 in terms of solid content.

  On the other hand, using a biaxially stretched polypropylene film subjected to corona discharge treatment (Daicel Chemical Industries, Ltd., W1H, count 20), a polyester adhesive diluted with methyl ethyl ketone (Toyobo Co., Ltd., Byron 30SS) is dried. After coating so that the subsequent film thickness was 0.3 μm, the film was dried at 80 ° C. for 30 seconds. A PVA / montmorillonite aqueous solution prepared on this adhesive layer was applied so that the film thickness after drying was 1 μm and then dried at 100 ° C. for 1 minute to obtain a gas barrier film. The results of evaluating the characteristics of the obtained film are shown in Table 1.

Comparative Example 5
Table 1 shows the results of evaluating the characteristics of a commercially available film (manufactured by Tosero Co., Ltd., AOP-SB) in which a layer of PVA and inorganic layered silicate is coated on a biaxially stretched polypropylene film.

  As is clear from the results in Table 1, the films of Examples 1 to 4 have high adhesion to the laminate layer and gas barrier properties. On the other hand, the films of Comparative Examples 1-2 and 4-5 have low adhesion to the laminate layer, and the film of Comparative Example 3 has low gas barrier properties. Moreover, the films of Comparative Examples 2 and 5 have low transparency.

Claims (13)

  A film in which a gas barrier layer composed of a water-soluble vinyl polymer and a swellable layered inorganic compound is formed on at least one surface of a substrate, and the arithmetic average roughness Ra of the gas barrier layer surface is 0.2. A gas barrier film having a root mean square roughness Rq of 0.2 or less and a ten-point average roughness Rzjis of 1.5 or less.   The film according to claim 1, wherein the swellable layered inorganic compound is composed of a smectite group clay mineral.   The film according to claim 1, wherein the swellable layered inorganic compound is fine particles dispersed in a solvent at a treatment pressure of 20 MPa or more.   The film according to claim 1, wherein the ratio (weight ratio) of the water-soluble vinyl polymer and the swellable layered inorganic compound is the former / the latter = 99/1 to 70/30.   The film according to claim 1, wherein the water-soluble vinyl polymer is composed of polyvinyl alcohol having a saponification degree of 96 mol% or more and a polymerization degree of 200 or more.   The film according to claim 1, wherein the gas barrier layer has a thickness of 0.2 to 2 μm.   The film according to claim 1, wherein an adhesive layer is interposed between the substrate and the gas barrier layer. The peel strength of the gas barrier layer subjected to lamination to the laminate layer is 2 N / 15 mm or more, the water vapor permeability in an atmosphere of 40 ° C. and 90% RH is 4 g / day / m ² or less, and the haze is 10% or less Item 1. The film according to Item 1.   A film in which a gas barrier layer composed of polyvinyl alcohol and montmorillonite is formed on at least one surface of a substrate composed of an olefin-based resin via an adhesive layer, and a ratio of polyvinyl alcohol and montmorillonite ( Weight ratio) is the former / the latter = 99/1 to 75/25, the arithmetic average roughness Ra of the gas barrier layer surface is 0.01 to 0.2, and the root mean square roughness Rq is 0.01 to The film according to claim 1, wherein 0.2 and ten-point average roughness Rzjis is 0.1 to 1.5.   The method for producing a film according to claim 1, wherein a coating liquid containing a water-soluble vinyl polymer and a swellable layered inorganic compound is applied to at least one surface of a substrate to form a gas barrier layer. A method of using fine particles dispersed multiple times in a solvent at a treatment pressure of 20 MPa or more as a functional layered inorganic compound. A laminate in which a laminate layer is further laminated on the gas barrier layer of the gas barrier film according to claim 1 via a laminate adhesive layer, and the coating amount of the laminate adhesive layer is 0.005 to 5 g / A laminate that is m ² .   A method for producing a laminate by forming a laminating adhesive layer on the gas barrier layer of the gas barrier film according to claim 1, and further laminating the laminating layer on the laminating adhesive layer.   The production method according to claim 12, wherein a laminate layer is extruded and laminated on the laminating adhesive layer.