JP2021133646A - Laminate film and method for producing the same - Google Patents

Abstract

To provide a release film that has releasability and sufficient oxygen barrier properties in a state of being stuck to an adherend.SOLUTION: A laminate film has a release layer, a base material, and a gas barrier layer. At least one outermost surface layer of the laminate film is the release layer. The release layer surface has a surface roughness parameter Sa (an arithmetical average height) of 0.05 μm or less. The gas barrier layer contains an inorganic laminar compound and a resin.SELECTED DRAWING: None

Description

The present invention relates to a laminated film and a method for producing the same.

The release film is widely used in the medical field and the industrial field. Specific examples thereof include protection for protecting process materials for manufacturing printed wiring boards, flexible printed wiring boards, multilayer printed wiring boards, medical tapes, haptics, adhesive materials, liquid crystal display parts, and the like. Materials can be mentioned.

For example, Patent Document 1 discloses a release film having an acid-modified polyolefin resin layer having good release properties for various adherends as a release layer.

International Publication No. 2009/025063

In recent years, in adherends whose yield and quality tend to deteriorate due to deterioration due to oxygen, the release film is provided with sufficient oxygen barrier performance, and the release film is a protective film that prevents oxidative deterioration of the adherend. It is also required to function as.
However, it is difficult for the release film disclosed in Patent Document 1 to obtain high gas barrier performance that can maintain the quality of the adherend with high performance and high functionality even if the gas barrier layer is provided. rice field.

In view of this problem, an object of the present invention is to provide a releasable film having releasability and sufficient oxygen barrier performance when attached to an adherend.

As a result of diligent studies to solve the above problems, the present inventors have a specific surface shape of a release layer containing a gas barrier layer containing an inorganic layered compound and a resin and constituting at least one outermost layer. We have found that the laminated film can solve the above problems, and have reached the present invention.

That is, the gist of the present invention is as follows.
(1) A laminated film including a release layer, a base material, and a gas barrier layer, wherein at least one outermost layer of the laminated film is a release layer.
The surface roughness parameter Sa (arithmetic mean height) of the release layer surface is 0.05 μm or less.
A laminated film characterized in that the gas barrier layer contains an inorganic layered compound and a resin.
(2) The laminated film according to (1), wherein the surface roughness parameter Sz (maximum height) of the surface of the release layer is 2.1 μm or less.
(3) The laminated film according to (1) or (2), wherein the release layer contains an acid-modified polyolefin resin and a cross-linking agent.
(4) The laminated film according to any one of (1) to (3), wherein the base material is a polyester film or a polyamide film.
(5) The method for producing the laminated film according to (3) above, wherein a liquid material for forming a release layer containing an acid-modified polyolefin resin, a cross-linking agent, and an aqueous medium is formed on one side of a base material. A method for producing a laminated film, which comprises a step of applying.
(6) The method for producing a laminated film according to (5) above, which comprises a step of drying and stretching a base material coated with a liquid material for forming a release layer.
(7) The method for producing the laminated film according to any one of (1) to (4) above, wherein a liquid material for forming a gas barrier layer containing an inorganic layered compound and a resin is formed on one side of a base material. A method for producing a laminated film, which comprises a step of applying.

Since the laminated film of the present invention has a gas barrier layer laminated and the surface of the laminated release layer has a smooth shape, when it is bonded to an adherend and heat-treated in an environment where oxygen is present. Even so, it has an excellent oxygen barrier property as a protective film for an adherend. Further, in the laminated film of the present invention, since the gas barrier layer contains an inorganic layered compound and a resin, the laminated film has good gas barrier properties and excellent bending resistance.

Hereinafter, the present invention will be described in detail.
The laminated film of the present invention is a laminated film including a release layer, a base material, and a gas barrier layer, at least one outermost layer of the laminated film is a release layer, and the surface of the release layer has a specific smoothness. , The gas barrier layer contains an inorganic layered compound and a resin.

<Base material>
Examples of the base material constituting the laminated film of the present invention include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), poly (1,4-cyclohexylene methylene terephthalate), and polylactic acid (polylactic acid). Polyamide film such as PLA), polyolefin film such as polypropylene, polystyrene film, polyamide 6, poly-p-xylylene adipamide (MXD6 nylon), polyamide 66, polyamide 46, polyamide 4T, polyamide 6T, polyamide 9T, etc. Films, polycarbonate films, polyacrylic nitrile films, polyimide films, multilayers of these (for example, polyamide 6 / MXD6 nylon / polyamide 6, polyamide 6 / ethylene-vinyl alcohol copolymer / polyamide 6) and mixtures are used. Therefore, polyester films and polyamide films having mechanical strength and dimensional stability are preferable.

The intrinsic viscosity of the resin constituting the base material is preferably 0.55 to 0.80, more preferably 0.60 to 0.75. If the intrinsic viscosity is less than the above range, cutting is likely to occur during film formation, stable production is difficult, and the strength of the obtained film is low. On the other hand, if the intrinsic viscosity exceeds the above range, shear heat generation increases during melt extrusion of the resin in the film production process, the load on the extruder increases, and the production speed must be sacrificed, or the film must be sacrificed. It becomes difficult to control the thickness of the film, and the productivity of the film decreases. Further, in the obtained film, thermal decomposition and gelation increase, and surface defects, foreign substances, and surface coarse protrusions increase. In addition, if the intrinsic viscosity is too high, the polymerization time and the polymerization process are long, which is a factor that pushes up the cost.

The polymerization method of the resin constituting the base material is not particularly limited, and in the case of polyester, for example, a transesterification method, a direct polymerization method and the like can be mentioned. Examples of the transesterification catalyst include oxides such as Mg, Mn, Zn, Ca, Li and Ti, and compounds such as acetate. Examples of the polycondensation catalyst include oxides such as Sb, Ti and Ge, and compounds such as acetate.
Since the polymerized polyester contains monomers, oligomers, acetaldehyde as a by-product, etc., it may be solid-phase polymerized at a temperature of 200 ° C. or higher under reduced pressure or an inert gas flow.

The base material may contain additives such as antioxidants, heat stabilizers, ultraviolet absorbers, antistatic agents, pinning agents and the like, if necessary. Examples of the antioxidant include hindered phenol compounds and hindered amine compounds, examples of the heat stabilizer include phosphorus compounds, and examples of the ultraviolet absorber include benzophenone compounds and benzotriazole compounds. Can be mentioned.

Next, an example of a method for producing a base material will be described using a polyester film as a specific example.
First, the fully dried polyester is fed to the extruder, melted above a sufficiently plasticized, fluid temperature, passed through a filter of choice as needed, and then sheeted through a T-die. Extrude to. This sheet is brought into close contact with a cooling drum whose temperature has been adjusted to be below the glass transition temperature (Tg) of polyester to obtain an unstretched film.
The obtained unstretched film is uniaxially oriented by a uniaxial stretching method or biaxially oriented by a biaxial stretching method. The biaxial stretching method is not particularly limited, but a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used.

In the uniaxial stretching method, the unstretched film is stretched in a temperature range of 50 ° C. higher than Tg to Tg of the resin in the longitudinal or width direction so as to have a stretching ratio of about 2 to 6 times.
In the simultaneous biaxial stretching method, the unstretched film is biaxially stretched in a temperature range of 50 ° C. higher than Tg to Tg of the resin so as to have a stretching ratio of about 2 to 4 times in the longitudinal direction and the width direction, respectively. Before leading to the simultaneous biaxial stretching machine, the unstretched film may be preliminarily stretched up to about 1.2 times.
Further, in the sequential biaxial stretching method, the unstretched film is heated by a heating roll, infrared rays, or the like and stretched in the longitudinal direction to obtain a vertically stretched film. The longitudinal stretching utilizes the difference in peripheral speed between two or more rolls, and the stretching ratio is preferably 2.5 to 4.0 times in the temperature range of 40 ° C. higher than Tg to Tg of polyester. The longitudinally stretched film is subsequently continuously subjected to lateral stretching, heat fixing, and heat relaxation treatments in the width direction to obtain a biaxially oriented film. The transverse stretching starts at a temperature 40 ° C. higher than the Tg to Tg of the resin, and the maximum temperature is preferably a temperature (100 to 40) ° C. lower than the melting point (Tm) of the resin. The magnification of lateral stretching is adjusted depending on the required physical properties of the final film, but is preferably 3.5 times or more, more preferably 3.8 times or more, and more preferably 4.0 times or more. .. It is also possible to increase the elastic modulus and dimensional stability of the film by stretching in the longitudinal direction and the width direction and then re-stretching in the longitudinal direction and / or the width direction.
Following the stretching, it is preferable to perform a heat fixing treatment for several seconds at a temperature (50 to 10) ° C. lower than the Tm of the resin, and at the same time, relax 1 to 10% in the film width direction at the same time as the heat fixing treatment. After the heat fixing treatment, the film is cooled to Tg or less to obtain a biaxially stretched film.

A single-layer film can be obtained by the above manufacturing method, but the base material constituting the laminated film may be a multilayer film formed by laminating two or more types of layers.
In the above-mentioned manufacturing method, the multilayer film is produced by melting the resins constituting each layer separately, extruding them using a multi-layer die, laminating and fusing them before solidification, and then biaxially stretching and heat-fixing them. It can be produced by a method in which two or more kinds of resins are separately melted and extruded to form a film, and they are laminated and fused in an unstretched state or after stretching. From the viewpoint of the simplicity of the process, it is preferable to use a multi-layer die and laminate and fuse before solidification.

The base material constituting the laminated film of the present invention has a multi-layer structure (for example, two-kind two-layer, two-kind three-layer, three-kind three-layer, four-layer or more multi-layer, etc.) even if it has a single-layer structure. However, a multi-layer structure is preferable from the viewpoint that the surface roughness can be controlled for each side and the handleability such as winding property can be improved. The composition of two types and two layers and two types and three layers is more preferable, and two types and two layers are even more preferable. The two-kind two-layer structure is a two-layer structure manufactured by using two kinds of layer-forming materials, and these two layers have different compositions (for example, particle content). The two-kind three-layer structure is a three-layer structure manufactured using two kinds of layer-forming materials, and the two outermost layers and the intermediate layer have different compositions (for example, particle content). There is. The three-kind three-layer structure is a three-layer structure manufactured by using three kinds of layer-forming materials, and these three layers have different compositions (for example, particle content) from each other.

The base material can also contain particles for the main purpose of imparting slipperiness and preventing scratches in each step. However, if the base material contains particles on the surface side on which the release layer is laminated, the surface roughness of the release layer may become rough, and the oxygen barrier performance when bonded to the adherend deteriorates. Therefore, it is preferable that the surface forming the release layer does not contain particles.

The type of particles contained is not particularly limited as long as it is a particle capable of imparting slipperiness, and specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples thereof include inorganic particles such as magnesium, kaolin, aluminum oxide and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin and benzoguanamine resin. Further, during the manufacturing process of the resin constituting the base material, precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed can also be used.

On the other hand, the shape of the contained particles is not particularly limited, and any of spherical, lumpy, rod-shaped, flat-shaped and the like may be used. Further, the hardness, specific gravity, color and the like are not particularly limited. Two or more kinds of these series of particles may be used in combination, if necessary.

The average particle size of the particles is usually 5 μm or less, preferably 0.1 to 3 μm. If the average particle size exceeds 5 μm, the surface roughness of the film becomes too rough, which may affect the surface shape of the molded surface to be transferred, for example, when used for transfer.

The particle content is usually 5% by mass or less, preferably 0.0003 to 3% by mass. If the particle content exceeds 5% by mass, the transparency of the film may be insufficient.

The method of adding the particles is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage of manufacturing the resin constituting each layer. In the case of the step of producing polyester, it is preferable to add it after the esterification or transesterification reaction is completed.

The thickness of the base material is not particularly limited as long as it can be formed as a film, but is usually 5 to 300 μm, preferably 10 to 150 μm from the viewpoint of mechanical strength, handleability, productivity and the like.

<Release layer>
In the laminated film of the present invention, a release layer is provided on at least one outermost layer of the laminated film.

The components constituting the release layer include silicone-based compounds, fluorine-containing copolymers, polyolefin-based resins, acid-modified polyolefin resins, polyester resins, epoxy resins, cyanato resins, polyether resins, polystyrene-based resins, and urethane resins. Examples thereof include polyamide resins, polyimide resins, long-chain alkyl group-containing compounds, acrylic resins, polyalkylene glycols, polyalkyleneimines, methyl celluloses, hydroxy celluloses, starches, and mixtures thereof. From the viewpoint of mold releasability, the components constituting the release layer are preferably polyolefin-based resins, acid-modified polyolefin resins, silicone-based compounds, fluorine-based compounds, long-chain alkyl group-containing compounds, acrylic resins, and mixtures thereof.

(Acid-modified polyolefin resin)
The acid-modified polyolefin resin is a resin containing an olefin component as a main component and modified by the acid-modified component.
The olefin component constituting the acid-modified polyolefin resin preferably contains at least one selected from ethylene, propylene, and butene, and more preferably contains propylene from the viewpoint of releasability from the epoxy prepreg. From the viewpoint of further improving the releasability from the epoxy prepreg, the content of propylene in the olefin component is preferably 50% by mass or more, more preferably 80% by mass or more, and 95% by mass or more. It is more preferable, and it is particularly preferable that it is 99% by mass or more.

Examples of the acid-modifying component constituting the acid-modified polyolefin resin include an unsaturated carboxylic acid component, and specifically, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, and the like. In addition to crotonic acid and the like, unsaturated dicarboxylic acid half esters, half amides and the like can be mentioned. Among them, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferable, and acrylic acid, methacrylic acid, and maleic anhydride are particularly preferable in order to stably disperse the resin in the aqueous dispersion of the resin described later. Two or more kinds of these acid-modifying components may be contained in the acid-modified polyolefin resin.

The proportion of the acid-modified component in the acid-modified polyolefin resin is preferably 1 to 10% by mass, more preferably 2 to 9% by mass. When the acid-modifying component is less than 1% by mass, the proportion of polar groups in the acid-modified polyolefin resin contained in the release layer is small, so that the release layer cannot obtain sufficient adhesion to the base material. It tends to contaminate adherends that have been released from the release layer. Further, in the aqueous dispersion of the resin described later, it tends to be difficult to stably disperse the resin. On the other hand, when the ratio of the acid-modified component exceeds 10% by mass, the ratio of polar groups increases, so that the adhesion between the release layer and the base material becomes sufficient, but the release layer and the adherend At the same time, the adhesion of the material is increased, so that the releasability from the adherend tends to decrease.

Further, the acid-modified polyolefin resin may contain an ethylenically unsaturated component containing an oxygen atom in the side chain for the reason of further improving the adhesion to the base material.
Examples of the ethylenically unsaturated component containing an oxygen atom in the side chain include an esterified product of (meth) acrylic acid and an alcohol having 1 to 30 carbon atoms. Among them, (meth) acrylic is easy to obtain. An esterified product of an acid and an alcohol having 1 to 20 carbon atoms is preferable. Specific examples of such compounds include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, and (meth) acrylic acid. Examples thereof include octyl, decyl (meth) acrylate, lauryl (meth) acrylate, dodecyl (meth) acrylate, and stearyl (meth) acrylate. A mixture of these may be used. Among these, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl acrylate, and octyl acrylate are more preferable from the viewpoint of adhesiveness to the polyester film, and ethyl acrylate, Butyl acrylate is more preferred, and ethyl acrylate is particularly preferred. "(Meta) acrylic acid ~" means "acrylic acid ~ or methacrylic acid ~".
The ethylenically unsaturated component containing an oxygen atom in the side chain has a polar group in the molecule like the acid-modified component. Therefore, by including an ethylenically unsaturated component containing an oxygen atom in the side chain in the acid-modified polyolefin resin, the release layer has high adhesion to the base film. However, if the amount of ethylenically unsaturated components containing oxygen atoms in the side chain is too large, the properties of the olefin-derived resin may be lost, and the release layer may have reduced releasability from the adherend. .. The proportion of the ethylenically unsaturated component containing an oxygen atom in the side chain in the acid-modified polyolefin resin is preferably 1 to 40% by mass, more preferably 2 to 35% by mass, and 3 to 30% by mass. It is more preferably%, and particularly preferably 6 to 18% by mass.
Even if an acid-modified polyolefin resin containing an ethylenically unsaturated component containing an oxygen atom is used in the side chain, the releasability of the released layer is not impaired in addition to the adhesion to the base material.

The acid-modified polyolefin resin may be copolymerized with other monomers in a small amount. Examples of other monomers include dienes, (meth) acrylonitrile, vinyl halides, vinylidene halides, carbon monoxide, sulfur dioxide and the like.

Each component constituting the acid-modified polyolefin resin may be copolymerized in the acid-modified polyolefin resin, and its form is not limited. Examples of the copolymerization state include random copolymerization, block copolymerization, and graft copolymerization (graft modification).

The melting point of the acid-modified polyolefin resin is preferably 80 to 200 ° C, more preferably 90 to 150 ° C. If the melting point exceeds 200 ° C., high temperature treatment may be required when forming a release layer on the surface of the base material. On the other hand, if the melting point is less than 80 ° C., the releasability of the release layer is lowered.

Acid-modified polyolefin resins that can be used in the present invention include Bondine series manufactured by Arkema, Nukurel series manufactured by Mitsui / DuPont Polychemicals, Lexpearl series manufactured by Nippon Polyethylene, and Yumex manufactured by Sanyo Kasei. Products such as the series, Evonik's Best Plastic series, Dow Chemical's Primacor series, Mitsui Chemicals' Admer series, and Toyobo's Toyo Tuck series can be mentioned.

(Long chain alkyl group-containing compound)
The long-chain alkyl group-containing compound is a compound having a linear or branched alkyl group having usually 6 or more carbon atoms, preferably 8 or more carbon atoms, and more preferably 12 or more carbon atoms. Examples of the alkyl group include a hexyl group, an octyl group, a decyl group, a lauryl group, an octadecyl group, a behenyl group and the like. The upper limit of the number of carbon atoms of the alkyl group is usually 30. Examples of the types of long-chain alkyl group-containing compounds include polymer compounds having various long-chain alkyl groups on the side chains, long-chain alkyl group-containing amine compounds, long-chain alkyl group-containing ether compounds, and long-chain alkyl group-containing quaternary compounds. Examples include quaternary ammonium salts. Considering heat resistance and stain resistance, it is preferably a polymer compound. Further, from the viewpoint of effectively obtaining releasability, a polymer compound having a long-chain alkyl group in the side chain is more preferable.

A polymer compound having a long-chain alkyl group in a side chain can be obtained by reacting a polymer compound having a reactive group with a compound having a long-chain alkyl group capable of reacting with the reactive group.
Examples of the reactive group include a hydroxyl group, an amino group, a carboxyl group, an acid anhydride and the like. Examples of the polymer compound having these reactive groups include polyvinyl alcohol, polyethyleneimine, polyethyleneamine, a polyester resin containing a reactive group, a poly (meth) acrylic resin containing a reactive group, and the like. Among these, polyvinyl alcohol is preferable in consideration of releasability and ease of handling.

Examples of the compound having a long-chain alkyl group capable of reacting with the above-mentioned reactive group include long-chain alkyl group-containing isocyanates such as hexyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate and behenyl isocyanate, and hexyl chloride. Examples thereof include long-chain alkyl group-containing chlorides such as octyl chloride, desiryl chloride, lauryl chloride, octadecyl chloride, and behenyl chloride, long-chain alkyl group-containing amines, and long-chain alkyl group-containing alcohols. Among these, long-chain alkyl group-containing isocyanates are preferable, and octadecyl isocyanates are particularly preferable, in consideration of releasability and ease of handling.

Further, the polymer compound having a long-chain alkyl group in the side chain can also be obtained by polymerizing a long-chain alkyl (meth) acrylate or copolymerizing a long-chain alkyl (meth) acrylate with another vinyl group-containing monomer. .. Examples of the long-chain alkyl (meth) acrylate include hexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, octadecyl (meth) acrylate, and behenyl (meth) acrylate. Be done.

(Polyvinyl alcohol)
In the present invention, the release layer preferably contains polyvinyl alcohol from the viewpoint of improving the release property. The polyvinyl alcohol is not particularly limited, and examples thereof include those obtained by completely or partially saponifying a polymer of vinyl ester. By containing polyvinyl alcohol in the release layer, it has the effect of improving the adhesion between the release layer and the base material and improving the releasability between the release layer and the adherend. The polyvinyl alcohol in the present invention preferably has water solubility for use as a liquid substance as described later.

From the viewpoint of surface smoothness of the release layer and releasability in a high temperature range, polyvinyl alcohol preferably has a saponification degree of 99% or less, more preferably 98% or less, and 95% or less. It is more preferable to have.

The content of polyvinyl alcohol is acid-modified from the viewpoint of improving the smoothness of the surface roughness of the release layer, improving the adhesion between the release layer and the base material, and improving the releasability between the release layer and the adherend. It is preferably 10 to 1000 parts by mass, more preferably 100 to 1000 parts by mass, further preferably 210 to 800 parts by mass, and 300 to 600 parts by mass with respect to 100 parts by mass of the polyolefin resin. Is particularly preferred.

In the present invention, commercially available polyvinyl alcohol can be used, for example, "VC-10", "JP-15", "JT-05", "JL-05E" manufactured by Japan Vam & Poval Co., Ltd. , "JM-33", "JM-17", "JF-05", "JF-10", "PVA-CST", "PVA-624", "PVA-" of "Kuraray Poval" manufactured by Kuraray Co., Ltd. "203", "PVA-220", "PVA-405" and the like can be used.

(acrylic resin)
The acrylic resin constituting the release layer is a polymer containing a polymerizable monomer having a carbon-carbon double bond, such as an acrylic-based or methacrylic-based monomer, and is a homopolymer or a copolymer. It may be any of.

The polymerizable monomer having a carbon-carbon double bond is not particularly limited, but typical compounds include, for example, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid. Various carboxyl group-containing monomers such as, and salts thereof; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutylhydroquilfumarate, mono. Various hydroxyl group-containing monomers such as butyl hydroxyitaconate; various (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate. ) Acrylate esters; various nitrogen-containing compounds such as (meth) acrylamide, diacetone acrylamide, N-methylol acrylamide, (meth) acrylonitrile, etc .; various nitrogen-containing compounds such as styrene, α-methylstyrene, divinylbenzene, vinyl toluene, etc. Various vinyl esters such as styrene derivatives and vinyl propionate; various silicon-containing polymerizable monomers such as γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane; phosphorus-containing vinyl-based monomers; vinyl chloride , Various vinyl halides such as billidene chloride; various conjugated dienes such as butadiene.

The acrylic resin includes not only homopolymers or copolymers composed of the above-mentioned polymerizable monomers having a carbon-carbon double bond, but also copolymers of these polymers and other polymers (for example, polyester, polyurethane, etc.). For example, block copolymers and graft copolymers can be mentioned.
Alternatively, a polymer (in some cases, a mixture of polymers) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in a polyester solution or a polyester dispersion is also included. Similarly, a polymer (in some cases, a mixture of polymers) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in a polyurethane solution or a polyurethane dispersion is also included. Similarly, a polymer (possibly a polymer mixture) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in another polymer solution or another polymer dispersion is also included.

Further, the acrylic resin can also contain a hydroxyl group and an amino group, and preferably contains a hydroxyl group from the viewpoint of suppressing a decrease in transparency of the release layer. When the acrylic resin contains a hydroxyl group, the hydroxyl value of the acrylic resin is preferably 2 to 100 mgKOH / g, more preferably 5 to 50 mgKOH / g. When the hydroxyl value of the acrylic resin is in the above range, the release layer has a good appearance and transparency.

(Crosslinking agent)
In the present invention, the release layer preferably contains a cross-linking agent together with the above resin and polyvinyl alcohol. By containing a cross-linking agent, the constituent components of the release layer are cross-linked to improve the release property, improve the cohesive force of the release layer, make it difficult to transfer to the adherend, and improve the water resistance. be able to.

The content of the cross-linking agent is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and further preferably 2 to 10 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin. preferable. When the content of the cross-linking agent is less than 1 part by mass, the release layer has a weak cohesive force, is inferior in adhesion to the base material, and tends to easily migrate to the adherend. On the other hand, if it exceeds 20 parts by mass, the release layer reacts with the adherend and becomes poor in releasability, or the liquid material for forming the release layer becomes thickened and the stability is lowered. I have something to do.

As the cross-linking agent, a compound having a plurality of functional groups that react with a carboxyl group in the molecule can be used, and a polyfunctional epoxy compound; a polyfunctional isocyanate compound; a polyfunctional aziridine compound; a carbodiimide group-containing compound; an oxazoline group-containing compound. Examples thereof include compounds; phenol resins; and amino resins such as urea compounds, melamine resins, and benzoguanamine resins. One of these may be used or two or more may be used in combination. Of these, polyfunctional isocyanate compounds, melamine compounds, urea compounds, polyfunctional epoxy compounds, carbodiimide group-containing compounds, oxazoline group-containing compounds and the like are preferable, carbodiimide group-containing compounds and oxazoline group-containing compounds are more preferable, and oxazoline group-containing compounds are preferable. More preferred. By using the oxazoline group-containing compound, it is possible to obtain a release film having excellent releasability with an adherend and adhesion with a substrate. Moreover, these cross-linking agents may be used in combination.

As the polyfunctional epoxy compound, specifically, a polyepoxy compound, a diepoxy compound and the like can be used. Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, and trimethylolpropane. Polyglycidyl ether can be used. Examples of the diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and polypropylene glycol di. Diglycidyl ether and polytetramethylene glycol diglycidyl ether can be used.

Examples of the polyfunctional isocyanate compound include tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, metaxylylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanate hexane, tolylene diisocyanate and hexanetriol. Additives, adducts of tolylene diisocyanate and trimethylolpropane, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalenediocyanate, 3,3'-Vitrilen-4,4'-diisocyanate,3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, metaphenylenediisocyanate and the like can be used. Blocked isocyanate compounds in which these isocyanate groups are blocked with phenols, alcohols, lactams, oximes, active methylene compounds and the like containing heavy sulfites and sulfonic acid groups may be used.
Examples of commercially available products of the polyfunctional isocyanate compound include "Basonato HW-100" manufactured by BASF.

As the polyfunctional aziridine compound, for example, N, N'-hexamethylene-1,6-bis- (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinyl propionate and the like can be used. be.

The carbodiimide group-containing compound is not particularly limited as long as it has one or more carbodiimide groups in the molecule. The carbodiimide compound forms an ester with two carboxyl groups in the acid-modified moiety of the acid-modified polyolefin resin in one carbodiimide moiety to achieve cross-linking. For example, compounds having a carbodiimide group such as p-phenylene-bis (2,6-xylylcarbodiimide), tetramethylene-bis (t-butylcarbodiimide), cyclohexane-1,4-bis (methylene-t-butylcarbodiimide). Alternatively, polycarbodiimide, which is a polymer having a carbodiimide group, can be used. One or more of these can be used. Among these, polycarbodiimide is preferable because of its ease of handling.
Examples of commercially available polycarbodiimide products include the carbodilite series manufactured by Nisshinbo, Ltd. Specifically, the water-soluble types "SV-02", "V-02", "V-02-L2", and " V-04 "; emulsion type" E-01 "," E-02 "; organic solution type" V-01 "," V-03 "," V-07 "," V-09 "; solvent-free The type "V-05" can be mentioned.

The oxazoline group-containing compound is not particularly limited as long as it has two or more oxazoline groups in the molecule. The oxazoline compound forms an amide ester with one carboxyl group in the acid-modified moiety of the acid-modified polyolefin resin at each of the two oxazoline moieties to achieve cross-linking. Such a polymer can be prepared by polymerization of an addition-polymerizable oxazoline group-containing monomer alone or with another monomer. Additionally polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, Examples thereof include 2-isopropenyl-4-methyl-2-oxazoline and 2-isopropenyl-5-ethyl-2-oxazoline. As the addition-polymerizable oxazoline group-containing monomer, one kind or a mixture of two or more kinds thereof can be used. Among these, 2-isopropenyl-2-oxazoline is suitable because it is easily available industrially. The other monomer is not limited as long as it is a monomer copolymerizable with the addition-polymerizable oxazoline group-containing monomer, and is, for example, alkyl acrylate, alkyl methacrylate (the alkyl group is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, etc. (Meta) acrylic acid esters such as n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene Unsaturated carboxylic acids such as sulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile and methacrylonitrile; acrylamide, methacrylamide, N-alkylacrylamide , N-alkylmethacrylate, N, N-dialkylacrylamide, N, N-dialkylmethacrylate (alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t- Unsaturated amides such as butyl group, 2-ethylhexyl group, cyclohexyl group, etc.; Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene Halogen-containing α, β-unsaturated aliphatic monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride; α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene can be mentioned. As the other monomer, one or more of these monomers can be used. Among these, an oxazoline group-containing polymer is preferable from the viewpoint of ease of handling.
Examples of commercially available oxazoline group-containing polymers include the Epocross series manufactured by Nippon Shokubai Co., Ltd. Specifically, the water-soluble types "WS-500" and "WS-700"; the emulsion type "K-1010E". , "K-1020E", "K-1030E", "K-2010E", "K-2020E", "K-2030E" and the like.

Examples of the phenol resin include alkyl phenols such as phenol, bisphenol A, pt-butylphenol, octylphenol, and p-cumylphenol, resol type phenol resins prepared from p-phenylphenol, cresol, and the like, and / or novolak type. Phenol resin can be used.

As the urea resin, for example, dimethylol urea, dimethylol ethylene urea, dimethylol propylene urea, tetramethylol acetylene urea, and 4-methoxy5-dimethylpropylene urea dimethylol can be used.

The melamine resin is, for example, a compound having an imino group, a methylol group, and / or an alkoxymethyl group (for example, a methoxymethyl group or a butoxymethyl group) as functional groups in one molecule. As the melamine resin, imino-based methylated melamine resin, methylol-based melamine resin, methylol-based methylated melamine resin, fully alkyl-type methylated melamine resin and the like can be used. Among them, methylolated melamine resin is the most preferable. Further, in order to promote the thermosetting of the melamine-based resin, it is preferable to use an acidic catalyst such as p-toluenesulfonic acid.

As the benzoguanamine resin, for example, trimethylolbenzoguanamine, hexamethylolbenzoguanamine, trismethoxymethylbenzoguanamine, hexakismethoxymethylbenzoguanamine and the like can be used.

(Glidant)
In the present invention, the release layer may contain a lubricant as long as the effect of the present invention is not impaired. As lubricants, for example, calcium carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, silicon oxide, sodium silicate, aluminum hydroxide, iron oxide, zirconium oxide, barium sulfate, titanium oxide, tin oxide, antimony trioxide, Inorganic particles such as carbon black and molybdenum disulfide, acrylic crosslinked polymers, styrene crosslinked polymers, silicone resins, fluororesins, benzoguanamine resins, phenolic resins, nylon resins, polyethylene wax and other organic particles, surfactants, etc. Can be mentioned.

(Characteristics of release layer)
In the present invention, the surface of the release layer constituting the outermost surface of the laminated film needs to have a surface roughness parameter Sa (arithmetic mean height) of 0.05 μm or less, and is 0.001 to 0.050 μm. It is preferably 0.001 to 0.030 μm, more preferably 0.001 to 0.010 μm. Since the surface roughness parameter Sa (arithmetic mean height) of the release layer is within the above range, the laminated film of the present invention is formed even when it is bonded to an adherend and heat-treated in an environment where oxygen is present. Can protect the bonded adherend from oxygen without deteriorating the oxygen barrier performance.

Further, in the present invention, the surface of the release layer constituting the outermost surface of the laminated film preferably has a surface roughness parameter Sz (maximum height) of 2.1 μm or less, and preferably 1.7 μm or less. More preferably, it is 1.0 μm or less. When the surface roughness parameter Sz of the release layer is within the above range, it is possible to further suppress the deterioration of the gas barrier property, although the reason is not clear.

In the laminated film of the present invention, the peeling force between the release layer and the acrylic adherend when the acrylic adherend is attached to the release layer and measured is 3.0 N / cm or less. It is preferably 2.8 N / cm or less, more preferably 2.6 N / cm or less. If the peeling force exceeds 3.0 N / cm, heavy peeling occurs, and it becomes difficult to practically use it as a release film.

Further, in the laminated film of the present invention, the peeling force between the release layer and the epoxy prepreg when the epoxy prepreg is attached to the release layer and measured is preferably 0.4 N / cm or less. It is more preferably 0.01 to 0.1 N / cm, and even more preferably 0.01 to 0.05 N / cm. When the peeling force exceeds 0.2 N / cm, it becomes difficult to peel from the epoxy prepreg, and the handleability is lowered.

In the present invention, the thickness of the release layer is preferably 0.01 to 1 μm, more preferably 0.03 to 0.7 μm, and even more preferably 0.05 to 0.5 μm. If the thickness of the release layer is less than 0.01 μm, sufficient releasability cannot be obtained, and if it exceeds 1 μm, it is easy to migrate to the adherend and the cost is increased, which is not preferable.

<Gas barrier layer>
The laminated film of the present invention needs to have a gas barrier layer laminated. The gas barrier layer needs to contain an inorganic layered compound and a resin component.

The inorganic layered compound contained in the gas barrier layer means an inorganic compound having a layered structure in which unit crystal layers are stacked on each other. In other words, the "layered compound" is a compound or substance having a layered structure, and the "layered structure" is a surface in which atoms are strongly bonded by covalent bonds or the like and are densely arranged, such as van der Waals force. It is a structure that is stacked in parallel due to the weak coupling force of.
The inorganic layered compound contained in the gas barrier layer is preferably a clay mineral. Clay minerals generally have a two-layer structure having an octahedral layer with aluminum, magnesium, etc. as the central metal above the tetrahedral layer of silica, and the tetrahedral layer of silica has aluminum, magnesium, etc. as the central metal. It is classified into a type having a three-layer structure in which the octahedral layer is sandwiched from both sides. Examples of the former include kaolinites and antigolites, and examples of the latter include smectites, vermiculites and mica depending on the number of interlayer cations. Specifically, kaolinite, dickite, chlorite, halloysite, antigolite, chrysotile, pyrophyllite, montmorillonite, hectorite, tetrasilic mica, sodium teniolite, muscovite, margarite, talc, vermiculite, phlogopite. , Phlogopite, chlorite, etc.

Examples of the resin contained in the gas barrier layer include resins having a hydrogen-binding group, for example, a hydroxyl group, an amino group, a thiol group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, and the like, and an ionic group, for example. Examples thereof include resins having a carboxylate group, a sulfonic acid ion group, a phosphoric acid ion group, an ammonium group, a phosphonium group and the like. Among them, a hydroxyl group, an amino group, a carboxyl group, a sulfonic acid group, a carboxylate group and a sulfonic acid ion group. A resin having an ammonium group or the like is preferable. The weight percentage of the hydrogen-bonding group or the ionic group per unit weight of the resin is preferably 20 to 60%, more preferably 30 to 50%.
Specific examples of the resin contained in the gas barrier layer include polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH) having a vinyl alcohol content of 41 mol% or more, polyvinylidene chloride (PVDC), and polyacrylonitrile (PAN). ), Hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, amylose, amylopectin, purulan, curdran, zantane, chitin, chitosan, cellulose, purulan, polysaccharides such as chitosan, polyacrylic acid and its esters, sodium polyacrylate. , Polybenzenesulfonic acid, sodium polybenzenesulfonate, polyethyleneimine, polyallylamine, its ammonium salt polyvinylthiol, polyglycerin and the like. Among these, the resin contained in the gas barrier layer is preferably polyvinyl alcohol or a polysaccharide.

The volume ratio of the inorganic layered compound to the resin (inorganic layered compound / resin) in the gas barrier layer is not particularly limited, but is preferably 5/95 to 90/10, and is preferably 5/95 to 50/50. Is more preferable. Further, when the volume ratio of the gas barrier layer is 5/95 to 30/70, the flexibility becomes good, and when the volume ratio is 7/93 to 17/83, the deterioration of the gas barrier property due to bending is suppressed, and the peel strength is peeled off. There are advantages such as improvement. If the volume ratio of the gas barrier layer is smaller than 5/95, the gas barrier performance becomes insufficient, and if it is larger than 90/10, the film forming property becomes poor.

The thickness of the gas barrier layer is preferably 0.10 to 0.50 μm, and more preferably 0.15 to 0.30 μm from the viewpoint of productivity. If the thickness of the gas barrier layer is less than 0.10 μm, the gas barrier property tends to be insufficiently exhibited under high temperature conditions. On the other hand, the formation of the gas barrier layer having a thickness of more than 0.50 μm has a limit in the drying ability of the coating liquid, and the production efficiency may decrease.

<Laminated film>
The laminated film of the present invention includes a release layer, a base material, and a gas barrier layer, and at least one of the outermost layers is a release layer. The layers between the release layer and the base material layer, the layers between the release layer and the gas barrier layer, the layers between the base material and the gas barrier layer, and the release layer are laminated as long as the effects of the present invention are not impaired. Another layer may be laminated on the surface of the laminated film which is not used. Examples of the layer laminated between the above layers include a layer such as an easy-adhesion layer, and examples of the layer laminated on the surface include a layer such as an antistatic layer.

The laminated film of the present invention can maintain the oxygen barrier performance even when it is bonded to an adherend and heat-treated (for example, at 180 ° C. for 30 minutes) in an environment where oxygen is present. In the release film on which the gas barrier layer is laminated, when the surface roughness parameter Sa on the surface of the release layer exceeds 0.05 μm, the transparency of the adherend is lowered in the heat treatment in the environment where oxygen is present. There was a case. Since the laminated film of the present invention maintains the oxygen barrier performance even when it is bonded to the adherend and heat-treated at 180 ° C. for 30 minutes in an environment where oxygen is present, the haze of the adherend can be increased. It can be suppressed.

^{The laminated film of the present invention preferably has an oxygen permeability of 50 cc / (m 2} · atm · day) or less under the condition of 20 ° C. × 0% RH in order to suppress oxidative deterioration of the adherend. Among them, 18 cc ^/ more preferably (m 2 · atm · day) or less, it is more preferably ^{15cc / (m 2 · atm ·} day) or less. When the oxygen permeability is greater than ^{50cc / (m 2 · atm ·} day), not completely prevent oxidation deterioration of the adherend, it may not be possible to hold the quality.

<Manufacturing method of laminated film>
As an example of the laminated film of the present invention, a laminated film having a structure consisting of a release layer / a base material / a gas barrier layer will be mentioned, and a method for producing the same will be described below.
The method for producing a laminated film of the present invention includes a step of applying a liquid material for forming a release layer on one side of a base material and a step of drying and stretching the base material coated with the liquid material for forming a release layer. Further, it is preferable to include a step of heat-fixing treatment. It also includes a step of applying a liquid material for forming a gas barrier layer on one side of the base material.

In the present invention, the liquid medium constituting the liquid material for forming the release layer and the liquid material for forming the gas barrier layer is preferably an aqueous medium. The aqueous medium means a solvent containing water and an amphipathic organic solvent and having a water content of 2% by mass or more, and may be water alone.
The amphipathic organic solvent means an organic solvent having a solubility of water in an organic solvent at 20 ° C. of 5% by mass or more (for the solubility of water in an organic solvent at 20 ° C., for example, "Solvent Handbook" (Kodansha). (Scientific, 1990, 10th edition), etc.).
Specific examples of the amphoteric organic solvent include alcohols such as methanol, ethanol, n-propanol and isopropanol, ethers such as tetrahydrofuran and 1,4-dioxane, ketones such as acetone and methyl ethyl ketone, methyl acetate and acetate-. Esters such as n-propyl, isopropyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate, ethylene glycol derivatives such as ethylene glycol-n-butyl ether, and diethylamine, triethylamine, diethanolamine, triethanolamine containing ammonia. , N, N-Dimethylethanolamine, organic amine compounds such as N, N-diethylethanolamine, lactams such as 2-pyrrolidone, N-methyl-2-pyrrolidone and the like.

The liquid material for forming the release layer is not limited to this method, but can be prepared, for example, by adding polyvinyl alcohol or a cross-linking agent to the liquid material of the acid-modified polyolefin resin.
As the liquid substance of the acid-modified polyolefin resin, an aqueous dispersion of the acid-modified polyolefin resin can be used. The method for aqueous dispersion of the acid-modified polyolefin resin is not particularly limited, and examples thereof include the method described in International Publication No. 02/055598.
The dispersed particle size of the acid-modified polyolefin resin in the aqueous medium is preferably a number average particle size of 1 μm or less from the viewpoint of stability when mixed with other components and storage stability after mixing. It is more preferably 8 μm or less. Such a particle size can be achieved by the production method described in International Publication No. 02/055598. The number average particle size of the acid-modified polyolefin resin is measured by a dynamic light scattering method.
The solid content concentration of the aqueous dispersion of the acid-modified polyolefin resin is not particularly limited, but is preferably 1 to 60% by mass, preferably 5 to 30% by mass in order to maintain an appropriate viscosity of the aqueous dispersion. More preferred.

The solid content concentration of the liquid material for forming the release layer can be appropriately selected depending on the lamination conditions, the target thickness, performance, and the like, and is not particularly limited. However, in order to maintain an appropriate viscosity of the liquid material and form a uniform release layer, 2 to 30% by mass is preferable, and 3 to 20% by mass is more preferable.
Antioxidants, ultraviolet absorbers, lubricants, colorants and the like can be added to the release layer forming liquid as long as its performance is not impaired.

In the present invention, as a method of applying a liquid substance for forming a release layer to a substrate, known methods such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, and spray are used. Examples thereof include coating, dipping coating, and brush coating, and the above-mentioned liquid material for forming a release layer is particularly effective for gravure roll coating because it can suppress the generation of minute non-planar shapes in the coating film. be.

As a method for applying the liquid material for forming a release layer, an offline method of applying the liquid material for forming a release layer to a pre-stretched film and an in-line method of drying and stretching a base film coated with the liquid material for forming a release layer are known. Therefore, in the present invention, it is preferable to apply the release layer forming liquid by an in-line method from the viewpoint of reducing the surface roughness parameter Sa on the surface of the release layer and improving the barrier property. When applied by the in-line method, the dispersed particles dispersed in the liquid material for forming the release layer can be formed at the same time as the coating film applied to the base film by the heat of stretching, and the particles are fused with each other. As a result, the surface roughness parameter Sa on the surface of the release layer becomes smaller.

Next, in the production of the laminated film of the present invention, a liquid material for forming a gas barrier layer containing an inorganic layered compound and a resin is applied to the other base material surface on which the release layer is formed to form a gas barrier. Laminate the layers.

The method for preparing the liquid material for forming the gas barrier layer containing the inorganic layered compound and the resin is not particularly limited, but for example, a method of mixing a solution in which the resin is dissolved and a dispersion in which the inorganic layered compound is swollen and opened. (Method 1), a method of adding a dispersion liquid obtained by swelling and opening an inorganic layered compound to a resin (method 2), and a method of adding an inorganic layered compound to a liquid in which a resin is dissolved and swelling and opening a dispersion (method 3). Further, a method (method 4) in which the resin and the inorganic layered compound are hot-kneaded and then mixed with the medium can be used. Above all, it is preferable to adopt method 3.

The inorganic layered compound contained in the liquid material for forming the gas barrier layer preferably has an average particle size of 800 to 3000 nm, and more preferably 1000 to 1800 nm. As the inorganic layered compound contained in the liquid material for forming the gas barrier layer, a compound having a relatively large average particle size is used, and a drying heat treatment for drying the coating film, which will be described later, is performed at a relatively high temperature to obtain high temperature conditions. A gas barrier layer capable of exhibiting excellent oxygen barrier properties can be obtained below.

In the production method of the present invention, it is preferable that the liquid material for forming the gas barrier layer is subjected to an ion exchange treatment on the inorganic layered compound by passing it through an ion exchange filter immediately before the liquid material is applied onto the substrate. By this ion exchange treatment, the ions of the inorganic layered compound in the liquid material for forming the gas barrier layer can be removed, and the inorganic layered compound can be cleaved to a state as close to a single layer as possible. Then, the inorganic layered compound having a relatively large surface is laminated without gaps in the gas barrier layer. Since the invasion of oxygen is blocked (a maze effect is obtained) by a large number of inorganic layered compounds laminated without gaps, excellent oxygen barrier properties are exhibited.
When the average particle size of the inorganic layered compound in the liquid material for forming the gas barrier layer is in the above range, a laminated film exhibiting excellent oxygen barrier properties can be obtained.
When the average particle size of the inorganic layered compound in the liquid material for forming the gas barrier layer is smaller than the above range, the formed gas barrier layer cannot sufficiently block the invasion of oxygen (the maze effect cannot be obtained) and is obtained. The laminated film is inferior in oxygen barrier property. Further, since the surface area of the inorganic layered compound increases and the frictional force between the inorganic layered compounds increases, the liquid material for forming the gas barrier layer causes an increase in viscosity. The liquid material for forming a gas barrier layer having an increased viscosity is liable to cause coating spots, and the obtained laminated film cannot exhibit excellent oxygen barrier properties, especially under high temperature conditions.
On the other hand, when the average particle size of the inorganic layered compound in the liquid material for forming the gas barrier layer is larger than the above range, it becomes difficult for the inorganic layered compound cleaved by the ion exchange treatment to be laminated without gaps in the gas barrier layer. Oxygen penetrates through the gaps in which the inorganic layered compounds are laminated, and the obtained laminated film has a low oxygen barrier property.
In order to adjust the average particle size of the inorganic layered compound contained in the liquid material for forming the gas barrier layer, the number of rotations, time, etc. in the disperser should be adjusted when preparing the dispersion liquid in which the inorganic layered compound is swollen and opened. Further, it is preferable to appropriately adjust the pressure and the like in the high-pressure disperser.

The method of laminating the gas barrier layer containing the inorganic layered compound and the resin on the base material using the above-mentioned liquid material for forming a gas barrier layer is not particularly limited, and the liquid material is applied, dried, and formed on the base material. A method of performing heat treatment is preferable.
The coating method includes a roll coating method such as a direct gravure method, a reverse gravure method, a micro gravure method, a two-roll beat coating method, a bottom feed three-roll reverse coating method, a doctor knife method, a die coating method, a dip coating method, and a bar. Examples include a coating method and a coating method combining these methods.

Then, after applying the liquid material for forming the gas barrier layer, a heat treatment is performed to dry the coating film. The dry heat treatment temperature is preferably 90 to 130 ° C, more preferably 100 to 130 ° C. If the dry heat treatment temperature is less than 90 ° C., the obtained gas barrier layer may not exhibit gas barrier properties under high temperature conditions due to poor drying. On the other hand, if the dry heat treatment temperature exceeds 130 ° C., the dimensional change of the base material may easily occur. The time of the dry heat treatment is preferably 2 to 10 seconds.

As the base material on which the liquid material for forming the gas barrier layer is applied, a base material having a thin film layer of metal or oxide, for example, a base material having a thin film layer of metal may be used. Then, at the interface between the thin film layer and the gas barrier layer, an adhesive layer may be introduced or a corona treatment may be carried out in order to improve the adhesiveness of both layers.
Further, the anchor coat layer may be laminated on the base material surface, and then the liquid material for forming the gas barrier layer may be applied. By passing through the anchor coat layer, it is possible to improve the adhesion between the base material and the gas barrier layer.
The component constituting the anchor coat layer is not particularly limited, and components and the like used in known or commercially available anchor coat agents can be used. For example, various compounds such as isocyanate-based, polyurethane-based, polyester-based, polyethyleneimine-based, polybutadiene-based, polyolefin-based, and alkyl titanate-based compounds can be mentioned. Among these, isocyanate-based, polyurethane-based, polyester-based and the like are particularly preferable in that the effects of the present invention can be obtained more reliably. Furthermore, 1) one or more mixtures and reaction products of isocyanate compounds, polyurethane and urethane prepolymers, and 2) mixtures of one or more of polyesters, polyols and polyethers with isocyanates and It is preferable to employ at least one mixture and / or reaction product consisting of the reaction product.
The thickness of the anchor coat layer is not particularly limited, but the dry thickness is preferably 0.02 to 0.2 μm, and more preferably 0.04 to 0.1 μm.

The laminated film of the present invention is in the form of a protective film for double-sided tape, an adhesive material, a component for a liquid crystal display, a protective material or a process material for manufacturing a printed wiring board, an ion exchange membrane, a ceramic green sheet, a heat radiating sheet, or the like. It can be suitably used for structure molding and the like.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto. The characteristics of the laminated film were measured by the following method.

(1) Release property against acrylic adhesive A acrylic adhesive tape (No. 31B / acrylic adhesive manufactured by Nitto Denko Co., Ltd.) with a width of 50 mm and a length of 150 mm is crimped with a rubber roll on the release layer side of the laminated film. Was used as a sample. The sample is sandwiched in the form of a metal plate / rubber plate / sample / rubber plate / metal plate, left for 20 hours in an atmosphere of 2 kPa load and 70 ° C., then cooled for 30 minutes or more and returned to room temperature to measure the peel strength. Got
The peeling force between the adhesive tape and the laminated film of the sample for measuring the peeling force was measured with a tensile tester (Autograph AGS-100B manufactured by Shimadzu Corporation) in a constant temperature room at 23 ° C. The peeling angle was 180 ° and the peeling speed was 300 mm / min.

(2) Releasability with respect to epoxy prepreg Both sides of an epoxy prepreg having a size of 60 mm × 100 mm (EI-6765 manufactured by Sumitomo Bakelite Co., Ltd., thickness 180 μm) are sandwiched between the release layer side of the obtained laminated film. In a 07 kPa (8 Torr) vacuum press, the temperature was raised from 30 ° C. to 150 ° C. at 15 ° C./min, held at 150 ° C. for 22 minutes, and then further raised to 190 ° C. at 5 ° C./min, 5 kg / min. After applying a pressure of cm ² for 10 minutes, the film was held at 190 ° C. for 70 minutes while applying a pressure of ^{15 kg / cm 2.} Then, by cooling to room temperature, a sample for mold releasability evaluation was obtained.
The peeling force of the obtained sample between the epoxy prepreg and the laminated film after curing was measured with a tensile tester (Autograph AGS-100B manufactured by Shimadzu Corporation) in a constant temperature room at 23 ° C. The peeling angle was 180 degrees and the peeling speed was 300 mm / min.

(3) Oxygen permeability The oxygen permeability of the obtained laminated film is relatively high at a temperature of 20 ° C. using a Mocon oxygen barrier measuring instrument (OX-TRAN 2/20 MH) based on the JIS K7126-2 method. The measurement was performed in an atmosphere of 0% humidity.

(4) Flexibility of Gas Barrier Layer The obtained laminated film was cut into a rectangle of 80 mm × 100 mm to prepare a test piece.
After sufficiently adjusting the state of the prepared test piece at a temperature of 20 ° C. and a humidity of 65% RH, the bending radius becomes 3.0 mm in a durability tester (DLDMLLH-FU type manufactured by Yuasa System Equipment Co., Ltd.). The bending test was performed 300,000 times in which the entire surface was folded 180 ° in the same atmosphere.
Then, using an oxygen barrier measuring device (OX-TRAN2 / 20 manufactured by Mocon), the oxygen permeability was measured under the same conditions as in (3).

(5) Gas barrier performance (amount of change in haze)
Based on JIS-K7136: 2000, the haze value before and after the heat treatment was measured using a haze meter NDH4000 (manufactured by Nippon Denshoku) according to the following procedure, and the difference was taken as the amount of haze change.
Both sides of a heat-resistant transparent adhesive sheet (LUCIACS CS9621T manufactured by Nitto Denko) (200 mm × 200 mm) were sandwiched between the release layer side of the obtained laminated film (200 mm × 200 mm) and pressure-bonded with a rubber roll. The haze value of the transparent adhesive sheet with the laminated film attached was measured.
Next, the transparent adhesive sheet with the laminated film attached was put into an oven at 180 ° C. and heat-treated for 30 minutes.
After the heat treatment, the haze value was measured for the central portion (50 mm × 100 mm) of the transparent adhesive sheet to which the laminated film was attached. The difference in haze value before and after heat treatment was determined as the amount of change in haze, and the gas barrier performance of the laminated film was evaluated. The heat treatment was performed in the atmosphere where oxygen is present.

(6) Surface Roughness For the surface roughness on the release layer side of the laminated film, TAYLOR / Hobson's Talisurf CCI6000 was used, and the surface roughness parameter Sa (arithmetic mean height) and surface roughness parameter were used under the following conditions. Sz (maximum height) was measured.
Measurement length: 0.66 mm x 0.66 mm
Cutoff: Robust Gaussian filter, 0.25 mm

A material for preparing a liquid material for forming a release layer was produced by the following method.

<Manufacture of Acid-Modified Polyolefin Resin A-1>
280 g of a propylene-butene-ethylene ternary copolymer (propylene / butene / ethylene = 68.0 / 16.0 / 16.0 (mass ratio)) was heated and melted in a four-necked flask under a nitrogen atmosphere. After that, while maintaining the internal temperature at 170 ° C. and stirring, 32.0 g of maleic anhydride as an unsaturated carboxylic acid and 6.0 g of dicumyl peroxide as a radical generator were added over 1 hour, respectively, and then reacted for 1 hour. rice field. After completion of the reaction, the obtained reaction product was put into a large amount of acetone to precipitate a resin. This resin was further washed with acetone several times to remove unreacted maleic anhydride, and then dried under reduced pressure in a vacuum drier to acid-modified polyolefin resin A-1 (acid-modified amount 7.0%, melting point 135). ℃) was obtained.

<Manufacture of acid-modified polyolefin resins A-2 and A-3>
In the production of the acid-modified polyolefin resin A-1, a propylene-butene-ethylene ternary copolymer (propylene / butene / ethylene = 68.0 / 16.0 / 16.0 (mass ratio)) was used as a propylene-ethylene. An acid-modified polyolefin resin A-2 (acid-modified amount 2.3%, melting point 145 ° C.) was obtained in the same manner except that the copolymer (propylene / ethylene = 99/1 (mass ratio)) was changed.
In the same manner, the acid-modified polyolefin resin A-3 (acid modification amount 2.0%) was changed to an ethylene-ethyl acrylate copolymer (ethylene / ethyl acrylate = 93/7 (mass ratio)). , Melting point 105 ° C.) was obtained.

<Manufacture of polymer compound A-4 having a long-chain alkyl group in the side chain>
200 parts of xylene and 600 parts of octadecyl isocyanate were added to a four-necked flask and heated under stirring. From the time when xylene began to reflux, 100 parts of polyvinyl alcohol (JP-15 manufactured by Japan Vam & Poval Co., Ltd.) having an average degree of polymerization of 500 and a saponification degree of 88 mol% was added little by little at 10-minute intervals for about 2 hours. .. After the addition of polyvinyl alcohol was completed, reflux was carried out for another 2 hours to complete the reaction. When the reaction mixture was cooled to about 80 ° C. and then added to methanol, the reaction product precipitated as a white precipitate. This precipitate was filtered off, 140 parts of xylene was added, and the mixture was heated to completely dissolve it. After that, the operation of adding methanol again and precipitating was repeated several times, and then the precipitate was washed with methanol and dried and pulverized to obtain a polymer compound A-4 having a long-chain alkyl group as a side chain.

<Production of an aqueous dispersion of acid-modified polyolefin resin A-1>
Using a stirrer equipped with a sealed glass container with a pressure resistance of 1 liter with a heater, 60.0 g of the acid-modified polyolefin resin A-1 produced by the above method and 45.0 g of ethylene glycol-n-butyl ether (boiling point). 171 ° C.), 6.9 g of N, N-dimethylethanolamine (boiling point: 134 ° C., 1.0 times equivalent to the carboxyl group of maleic anhydride in the resin) and 188.1 g of distilled water. , The mixture was placed in the above glass container, and the stirring blade was stirred at a rotation speed of 300 rpm. As a result, no resin precipitation was observed at the bottom of the container, and it was confirmed that the container was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the temperature inside the system was maintained at 140 ° C., and the mixture was further stirred for 60 minutes. Then, it was cooled to room temperature (about 25 ° C.) by air cooling while stirring at a rotation speed of 300 rpm. Furthermore, by pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave), a uniform aqueous dispersion of acid-modified polyolefin resin A-1 (solid content concentration 25 mass) %) Was obtained. There was almost no residual resin on the filter.

<Manufacturing of aqueous dispersions of acid-modified polyolefin resins A-2 and A-3>
An aqueous dispersion of the acid-modified polyolefin resins A-2 and A-3 (solid content concentration: 25% by mass) in the same manner as described above except that the acid-modified polyolefin resins used are changed to A-2 and A-3. ) Was obtained.

<Preparation of Acrylic Resin A-5 Aqueous Dispersion>
Emulsion polymerization (emulsifier: anionic surfactant) of ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-methylolacrylamide / acrylic acid with a composition of 65/21/10/2/2 (mass%), acrylic An aqueous dispersion of resin A-5 (hydroxyl value 11 mgKOH / g) was obtained.

The following aqueous solution was used as the polyvinyl alcohol for preparing the liquid material for forming the release layer.
-VC-10: VC-10 manufactured by Japan Vam & Poval Co., Ltd., saponification rate 99.3%, degree of polymerization 1,000, solid content concentration 8% by mass
-JT-05: JT-05 manufactured by Japan Vam & Poval Co., Ltd., saponification rate 94.5%, degree of polymerization 500, solid content concentration 8% by mass
-JF-10: JF-10 manufactured by Japan Vam & Poval Co., Ltd., saponification rate 98.5%, degree of polymerization 1,000, solid content concentration 8% by mass

The following were used as the cross-linking agent.
WS-700: Epocross WS-700 manufactured by Nippon Shokubai Co., Ltd., an aqueous solution of an oxazoline group-containing compound, a solid content concentration of 25% by mass.
-S-260: Nikaredoin S-260 manufactured by Nippon Carbide Industry Co., Ltd., methylol melamine

<Preparation of liquid P-1 for mold release layer formation>
An aqueous dispersion of the acid-modified polyolefin resin A-1, a polyvinyl alcohol aqueous solution "VC-10", and an aqueous solution of an oxazoline group-containing compound as a cross-linking agent "WS-700" each having a solid content of 100 parts by mass. , 300 parts by mass and 8 parts by mass, and adjusted with water so that the final solid content concentration is 6.5% by mass to obtain a liquid material P-1 for forming a release layer. rice field.

<Preparation of liquid P-2 for mold release layer formation>
An aqueous dispersion of the acid-modified polyolefin resin A-2, an aqueous polyvinyl alcohol solution "JT-05", and an aqueous solution "WS-700" of an oxazoline group-containing compound as a cross-linking agent each having a solid content of 100 parts by mass. , 500 parts by mass and 8 parts by mass, and adjusted with water so that the final solid content concentration is 6.5% by mass to obtain a liquid material P-2 for forming a release layer. rice field.

<Preparation of liquid P-3 for mold release layer formation>
An aqueous dispersion of the acid-modified polyolefin resin A-3, an aqueous polyvinyl alcohol solution "JF-10", and an aqueous solution "WS-700" of an oxazoline group-containing compound as a cross-linking agent each having a solid content of 100 parts by mass. , 500 parts by mass and 8 parts by mass, and adjusted with water so that the final solid content concentration is 6.5% by mass to obtain a liquid material P-3 for forming a release layer. rice field.

<Preparation of liquid P-4 for mold release layer formation>
The polymer compound A-4 having a long-chain alkyl group in the side chain, the aqueous dispersion of the acrylic resin A-5, and the cross-linking agent methylol melamine (S-260) have a solid content mass ratio of 30 / The mixture was mixed so as to be 40/30, and finally adjusted with water so that the solid content concentration was 3.0% by mass to obtain a liquid material P-4 for forming a release layer.

<Preparation of liquid P-5 for mold release layer formation>
An aqueous dispersion of the acid-modified polyolefin resin A-2, a polyvinyl alcohol aqueous solution "VC-10", and an aqueous solution "WS-700" of an oxazoline group-containing compound as a cross-linking agent each having a solid content of 100 parts by mass. , 300 parts by mass and 8 parts by mass, and adjusted with water so that the final solid content concentration is 6.5% by mass to obtain a liquid material P-5 for forming a release layer. rice field.

<Preparation of liquid P-6 for mold release layer formation>
The aqueous dispersion of the acid-modified polyolefin resin A-2 and the aqueous solution "WS-700" of the oxazoline group-containing compound as a cross-linking agent have solid contents of 100 parts by mass and 8 parts by mass, respectively. The mixture was mixed and adjusted with water so that the final solid content concentration was 6.5% by mass to obtain a liquid material P-6 for forming a release layer.

<Preparation of anchor coating agent>
EL-510-1-17K, CAT-87RT (EL-510-1-17K / CAT-87RT = 5/1 (mass ratio)) manufactured by Toyo Morton Co., Ltd., and a solvent (toluene / MEK / isobutyl acetate = 5/4) The concentration was adjusted to 4% by mass at 1/1 (mass ratio).

<Manufacturing of liquid material for forming gas barrier layer>
In a dispersion kettle, ion-exchanged water (0.7 μS / cm or less) and an ethylene-vinyl alcohol copolymer having a vinyl alcohol content of 97 mol% as a resin component (B) (Kuraray Exevar RS-2117, Ken) The degree of polymerization is 97.5-99.0%, the degree of polymerization is 1700), the temperature is raised to 95 ° C. under low-speed stirring (800 rpm, peripheral speed 2 m / min), and the mixture is stirred at the same temperature for 30 minutes to make polyvinyl alcohol. Was dissolved, and then cooled to 60 ° C. to obtain a 9.0 mass% polyvinyl alcohol aqueous solution. To this polyvinyl alcohol aqueous solution, an alcohol aqueous solution (ion-exchanged water / 2-propanol = 4/1 (mass ratio)) in which ion-exchanged water and 2-propanol were mixed was added over 10 minutes, and high-speed stirring (1600 rpm, peripheral speed) was performed. The mixture was switched to 4 m / min) and stirred for 20 minutes to obtain a 6.4 mass% aqueous solution of polyvinyl alcohol.
An inorganic layered compound (montmorillonite, Kunipia RG manufactured by Kunimine Kogyo Co., Ltd.) was gradually added to the obtained polyvinyl alcohol aqueous solution, and after completion of the addition, high-speed stirring (1600 rpm, peripheral speed 4 m / min) was continued at 60 ° C. for 60 minutes. Then, 2-propanol was further added over 10 minutes, and the mixed solution was cooled to room temperature to obtain a preparatory solution. To this preparatory liquid, 0.01% by mass of a nonionic surfactant (SH3746 manufactured by Toray Dow Corning) was added, and 1000 kgf / cm ^{2 was used using a high-pressure disperser (ultra-high pressure homogenizer manufactured by Microfluidizer).} Processed under the conditions of. Next, 10 alcohol aqueous solutions (ion-exchanged water / 2-propanol = 1 / 1.2 (mass ratio)) in which ion-exchanged water and 2-propanol were mixed were added so that the final solid content concentration was 5.0% by mass. The mixture was added over a minute, and stirred at high speed for 20 minutes (1600 rpm, peripheral speed 4 m / min) to obtain a liquid substance. The volume ratio of the inorganic layered compound to the resin (inorganic layered compound / resin) in the obtained liquid material is 10/90.

Example 1
<Manufacturing of base material>
Polyethylene terephthalate A (polymerization catalyst: antimony trioxide, intrinsic viscosity: 0.62, glass transition temperature: 78 ° C., melting point: 255 ° C.) plus 0.07% by mass of silica particles (particle size 2.3 μm). The terephthalate B is put into the extruder I (screw diameter: 50 mm), and the polyethylene terephthalate A is put into the extruder II (screw diameter: 65 mm) to melt at 280 ° C. It was merged and laminated in layers before reaching. The thickness ratio (I / II) of the layers was adjusted to 4/6, and the total thickness was adjusted to 600 μm, extruded from the T-die outlet, and rapidly cooled and solidified to obtain an unstretched film.
This unstretched film was stretched 3.5 times with a roll type longitudinal stretching machine under the condition of 85 ° C.
<Formation of release layer>
Next, the liquid material (P-1) for forming a release layer produced by the above method was applied to the surface of the film layer from the extruder II with a 120-mesh gravure roll so as to be ^{5 g / m 2.} , The end of the film was continuously gripped by a clip of a flat drawing machine, stretched 4.5 times laterally under the condition of 100 ° C., and then the lateral relaxation rate was set to 3% at 243 ° C. The heat treatment was carried out for 3 seconds to obtain a 38 μm-thick film in which a release layer having a thickness of 0.1 μm was provided on one side of a two-layer, two-layer base material.
The obtained film provided with the release layer uses a pressure-contact roll (maximum height SRmax is 7 μm) having a hard chrome plating on the surface, and has a width on a paper tube having an outer diameter of 10.5 cm. The film was wound on a roll having a length of 500 m under the conditions of 800 mm, winding tension 118 N / m, winding contact pressure 118 N / m, and winding speed 100 m / min. The friction coefficient of the contact pressure roll was 0.3, and the holding angle of the film was 120 °.
<Formation of gas barrier layer>
The obtained release layer was provided, and an anchor coating agent was gravure-coated on the opposite surface of the release layer of the film, and dried in a hot air dryer at 80 ° C. for 1 minute to form an anchor coat layer. The dry thickness of this anchor coat layer was 0.03 μm.
A liquid material for forming a gas barrier layer was gravure-coated on the anchor coat layer, and then dried with a hot air dryer at 80 ° C. for 1 minute to form a gas barrier layer. The film thickness (dry thickness) of the gas barrier layer was 0.3 μm.

Examples 2-6
A laminated film was obtained in the same manner as in Example 1 except that the type of the liquid material for forming the release layer was changed as shown in Table 1.

Example 7
An unstretched film was obtained in the same manner as in Example 1.
The unstretched film was stretched 3.5 times with a roll-type longitudinal stretching machine under the condition of 90 ° C. to obtain a stretched film.
This vertically stretched film was stretched 4.5 times at 120 ° C. in a transversely stretched tenter, heat-treated at 230 ° C. for 10 seconds, cooled and wound. The thickness of the obtained biaxially stretched film was 38 μm.
A liquid material P-2 for forming a release layer was applied to one side of the obtained biaxially stretched film (the side of the layer made of polyethylene terephthalate (B)) using a Meyer bar, and dried at 150 ° C. for 90 seconds. rice field. Then, a liquid material for forming a gas barrier layer was applied to one side (II side) of the biaxially stretched film using a Meyer bar, and dried at 80 ° C. for 1 minute.
Then, by aging at 50 ° C. for 2 days, a polyester film having a release layer and having a gas barrier layer on the opposite surface of the release layer was obtained to obtain a polyester film having a thickness of 38 μm.

Comparative Examples 1 to 4
A film in which the release layers were laminated was produced in the same manner as in Examples 1 to 4 except that the gas barrier layer was not provided.

Comparative Example 5
Polyethylene terephthalate B is put into an extruder II (screw diameter: 65 mm) and melted at 280 ° C., and then each melt is adjusted to a total thickness of 600 μm and extruded from the T-die outlet to quench and solidify. A laminated film was obtained in the same manner as in Example 1 except that an unstretched film was obtained.

Comparative Example 6
A laminated film was obtained in the same manner as in Comparative Example 5 except that the type of the liquid material for forming the release layer was changed as shown in Table 1.

Comparative Example 7
Using the laminated film produced in Comparative Example 2 in which only the release layer is laminated, aluminum is introduced into the opposite surface of the release layer by a vacuum vapor deposition method while introducing oxygen gas with a vacuum vapor deposition machine. As a gas barrier layer composed of the above, an aluminum oxide thin film layer having a thickness of 6 nm was laminated.
Next, a mixture obtained by mixing 100 parts by mass of an aqueous urethane resin (Takelac WPB341 manufactured by Mitsui Chemicals, Inc.) and 10 parts by mass of an isocyanate-based silane coupling agent (KBE9007, manufactured by Shin-Etsu Chemical Co., Ltd.) on an aluminum oxide thin film layer. The resin was applied by a gravure coating method, and a top coat layer having a thickness of 0.2 μm was laminated to obtain a laminated film.

Comparative Example 8
A liquid material P-2 for forming a release layer was applied to one side of a biaxially stretched polyester resin film (Unitika "Emblet PET-12", thickness 12 μm) using a Meyer bar, and 90 at 150 ° C. Allowed to dry for seconds. Then, a liquid material for forming a gas barrier layer was applied to the opposite surface to which the release layer of the biaxially stretched film was applied using a Meyer bar, and dried at 80 ° C. for 1 minute. Then, by aging at 50 ° C. for 2 days, a polyester film having a release layer and having a gas barrier layer on the opposite surface of the release layer was obtained to obtain a polyester film having a thickness of 12 μm.

Table 1 shows the results of various evaluations of the laminated films obtained in Examples and Comparative Examples.

Since the laminated films of Examples 1 to 7 have the gas barrier layer laminated and the value of the surface roughness parameter Sa of the release layer is small, the laminated film has excellent oxygen barrier properties, and the adherend to which the laminated film is bonded is in the atmosphere. The amount of haze change before and after the heat treatment was small, and oxidative deterioration was suppressed.
Since the laminated films of Comparative Examples 1 to 4 did not have a gas barrier layer, they were inferior in gas barrier performance.
The laminated films of Comparative Examples 5, 6 and 8 are inferior in oxygen barrier property because the value of the surface roughness parameter Sa of the release layer is large, and the adherend to which the laminated films are attached has a haze before and after the heat treatment in the atmosphere. The amount of change in the value became large, and oxidative deterioration was observed.
Since the laminated film of Comparative Example 7 was provided with a metal film-based gas barrier layer, the oxygen barrier property after the bending resistance test was inferior.

Claims (7)

A laminated film including a release layer, a base material, and a gas barrier layer, wherein at least one outermost layer of the laminated film is a release layer.
The surface roughness parameter Sa (arithmetic mean height) of the release layer surface is 0.05 μm or less.
A laminated film characterized in that the gas barrier layer contains an inorganic layered compound and a resin. The laminated film according to claim 1, wherein the surface roughness parameter Sz (maximum height) of the surface of the release layer is 2.1 μm or less. The laminated film according to claim 1 or 2, wherein the release layer contains an acid-modified polyolefin resin and a cross-linking agent. The laminated film according to any one of claims 1 to 3, wherein the base material is a polyester film or a polyamide film. The method for producing the laminated film according to claim 3, wherein a liquid material for forming a release layer containing an acid-modified polyolefin resin, a cross-linking agent, and an aqueous medium is applied to one side of the base material. A method for producing a laminated film, which comprises. The method for producing a laminated film according to claim 5, further comprising a step of drying and stretching a base material coated with a liquid material for forming a release layer. The method for producing the laminated film according to any one of claims 1 to 4, wherein the step of applying a liquid material for forming a gas barrier layer containing an inorganic layered compound and a resin to one side of the base material is included. A method for producing a laminated film.