Multilayered structure and its manufacturing method

The present invention relates to a multilayer structure and a method for producing a multilayer structure.

Conventionally, molded products made of thermoplastic resins such as polypropylene, polyester, and polyamide have been used in many fields such as food fields, cosmetics fields, agrochemical fields, and medical fields due to their excellent mechanical properties, heat resistance, and transparency. , Widely used as a packaging material. When a thermoplastic resin molded body is used as a packaging material, gas barrier properties are often required in order to prevent the contents from being deteriorated by oxygen. As a packaging material having such a gas barrier property, for example, Patent Document 1 discloses a packaging material in which a layer composed of polyvinyl alcohol and synthetic hectorite, which is an inorganic layered compound, is further laminated on a base film. ..

<patcit num="1"><text>Japanese Unexamined Patent Publication No. 03-30944</text></patcit>

<p> However, as described above, the packaging material having one layer containing the inorganic layered compound has insufficient gas barrier properties under high humidity conditions.</p><p> The present invention provides a method for producing a multilayer structure having excellent gas barrier properties under high humidity conditions and a multilayer structure having excellent gas barrier properties under high humidity conditions.</p>

<p> The present invention comprises a first layer made of a first material containing a first inorganic layered compound and a first layer containing the inorganic layered compound at a volume fraction higher than the volume fraction of the inorganic layered compound in the first material. It is a multi-layer structure having a second layer made of two materials, and the first layer and the second layer are laminated adjacent to each other. Further, in another aspect, the present invention is a volume fraction of a base material layer, a first layer composed of a first material containing a first inorganic layered compound, and a first inorganic layered compound in the first material. It has a second layer made of a second material containing a second inorganic layered compound having a volume fraction higher than the volume fraction, and the first layer is laminated on the base material layer, and the first layer is further laminated. A method for producing a multilayer structure in which the second layer is adjacently laminated on one layer, and the method is: A first coating liquid made of the first liquid medium and the first material contained therein is applied onto the base material layer, and then the liquid medium is removed to remove the first material made of the first material. The step of forming the layer of the above on the base material layer, and A second coating liquid consisting of the second liquid medium and the second material contained therein is applied onto the first layer, and then the liquid medium is removed from the second material. A step of forming a second layer to be formed on the first layer. Including In the first coating liquid and the second coating liquid, the ratio of the dry volume of the second inorganic layered compound to the dry volume of the second material is the ratio of the dry volume of the first material to the dry volume of the first material. It is a method for producing a multilayer structure that satisfies the requirement that it is higher than the ratio of the dry volume of the first inorganic layered compound.</p>

<p> The multilayer structure of the present invention has excellent gas barrier properties under high humidity conditions. Further, the method for producing a multilayer structure of the present invention can produce a multilayer structure having excellent gas barrier properties under high humidity conditions.</p>

The multilayer structure of the present invention has a first layer composed of a first material containing a first inorganic layered compound, and an inorganic layered structure having a volume fraction higher than the volume fraction of the inorganic layered compound in the first material. It has a second layer consisting of a second material containing the compound. As the inorganic layered compound contained in the first layer and the inorganic layered compound contained in the second layer, clay minerals having swelling property and cleavage property in a solvent are preferably used, respectively. The inorganic layered compound of the present invention refers to a compound in which unit crystal layers are stacked on each other to form a layered structure. The layered structure refers to a structure in which planes in which atoms are strongly bonded by covalent bonds or the like and are densely arranged are stacked substantially in parallel by a weak bonding force such as van der Waals. Among the inorganic layered compounds, clay minerals having swellability to a solvent are particularly preferably used.

Clay minerals are generally of the type having a two-layer structure having (i) an octahedral layer with aluminum, magnesium, etc. as the central metal above the tetrahedral layer of silica, and (ii) the tetrahedral layer of silica being aluminum. It is classified into a type having a three-layer structure in which an octahedral layer with a central metal such as magnesium or magnesium is narrowed from both sides. Examples of the two-layer structure type viscous mineral of (i) include clay minerals of the kaolinite group and the antigolite group. Examples of the three-layer structure type clay mineral of (ii) include clay minerals of the smectite group, vermiculite group, and mica group depending on the number of interlayer cations.

These clay minerals include kaolinite, dickite, nacrite, halloysite, antigolite, chrysotile, pyrophyllite, montmorillonite, byderite, nontronite, saponite, saponite, stibunkite hectolite, tetrasilic mica, and sodium teniolite. , Muscovite, Margarite, Tarku, Vermiculite, Phlogopite, Zansophyllite, Chlorite, etc. In addition, these clay minerals are treated with organic substances such as ion exchange to improve their dispersibility (see Asakura Shoten, "Clay Encyclopedia"; hereinafter, sometimes referred to as organically modified clay minerals) as inorganic layered compounds. Can be used. As the organic substance for treating clay minerals, quaternary ammonium salts such as dimethyl distearyl ammonium salt and trimethyl stearyl ammonium salt, phosphonium salt, imidazolium salt and the like can be used.

Among the above clay minerals, clay minerals of the smectite group, vermiculite group and mica group are preferable, and the smectite group is particularly preferable. Examples of the smectite tribe include montmorillonite, biderite, nontronite, saponite, saponite, stebunsite, and hectorite. In particular, montmorillonite is preferably used.

The aspect ratio of the inorganic layered compound contained in the first layer and the inorganic layered compound contained in the second layer is not particularly limited, but those of 200 to 3000 are preferably used. If the aspect ratio of the inorganic layered compound is too small, the gas barrier property tends to be insufficient, and if the aspect ratio is too large, it becomes difficult to swell and cleave, and the gas barrier property tends to be insufficient. ..

The inorganic layered compound contained in the first layer and the inorganic layered compound contained in the second layer preferably have an average particle size of 5 μm or less. If the average particle size is too large, the gas barrier property, transparency, and film forming property tend to be inferior, and it is preferably 1 μm or less especially in applications where transparency is required.

In the present invention, the aspect ratio (Z) of the inorganic layered compound is defined by the formula: Z = L / a. In the formula, L is the average particle size of the inorganic layered compound, and a is the unit thickness of the inorganic layered compound, that is, the thickness of the unit crystal layer of the inorganic layered compound. (A) (published by Kagaku Dojinsha in 1985, supervised by Jiro Shiokawa), p. 69).

The average particle size of the inorganic layered compound is a particle size (volume-based median diameter) determined by a diffraction / scattering method in a liquid medium. That is, it can be obtained by calculating the particle size distribution most consistent with the diffraction / scattering pattern from the diffraction / scattering pattern obtained when light is passed through the dispersion liquid of the inorganic layered compound by the Mie scattering theory or the like. it can. Specifically, for example, the measurement range of the particle size distribution is divided into appropriate sections, the representative particle size is determined for each section, and the particle size distribution, which is originally a continuous quantity, is converted into a discrete quantity for calculation. The method can be mentioned. When the inorganic layered compound is sufficiently swollen and opened in a liquid medium of the same type as the liquid medium used when determining the average particle size of the inorganic layered compound by the diffraction / scattering method, and then mixed with a resin or the like, it is contained in the resin. The particle size of the swollen and opened inorganic layered compound can be regarded as substantially equal to the particle size of the inorganic layered compound measured in the liquid medium.

As the inorganic layered compound contained in the first layer and the inorganic layered compound contained in the second layer, specifically, those having a swelling value of 5 or more according to the swellability test described below are preferable, and the swelling value is 20 or more. Is more preferable. Further, the cleavage value according to the following cleavage test is preferably 5 or more, and more preferably 20 or more.

[Swellability test] Place 100 ml of liquid medium in a 100 ml graduated cylinder, and gradually add 2 g of the inorganic layered compound to this. After allowing to stand at 23 ° C for 24 hours, read the volume (ml) of the inorganic layered compound dispersion layer from the scale of the interface between the inorganic layered compound dispersion layer and the supernatant in the measuring cylinder. The larger this value (swelling value) is, the higher the swelling property is.

[Cleavage test] Gradually add 30 g of the inorganic layered compound into 1,500 ml of the liquid medium, and disperser (manufactured by Asada Iron Works Co., Ltd., Despa MH-L, blade diameter 52 mm, rotation speed 3,100 rpm, container capacity 3 L, bottom-blade distance 28 mm). After dispersing at a peripheral speed of 8.5 m / min for 90 minutes at 23 ° C, 100 ml of this dispersion is collected in a measuring cylinder. After allowing to stand for 60 minutes, read the volume (ml) of the inorganic layered compound dispersion layer from the scale of the interface between the layered compound dispersion layer and the supernatant in the measuring cylinder. The larger this value (cleavage value) is, the higher the cleavage property is.

As a liquid medium for swelling and opening the inorganic layered compound, when the inorganic layered compound is a hydrophilic swelling clay mineral, water, alcohols (methanol, ethanol, propanol, isopropanol, ethylene glycol, diethylene glycol, etc.), dimethyl Examples thereof include formamide, dimethylsulfoxide and acetone, but water, alcohol and water-alcohol mixture are particularly preferable.

When the inorganic layered compound is an organically modified clay mineral, aromatic hydrocarbons such as benzene, toluene and xylene, ethers such as ethyl ether and tetrahydrofuran, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, n -Aliphatic hydrocarbons such as pentane, n-hexane, n-octane, halogenated hydrocarbons such as chlorobenzene, carbon tetrachloride, chloroform, dichloromethane, 1,2-dichloroethane, perchloroethylene, ethyl acetate, methacrylic acid Methyl, dioctyl phthalate, dimethylformamide, dimethylsulfoxide, methylserosolve, silicon oil and the like can be used as the liquid medium.

The first layer may contain one kind of inorganic layered compound or may contain two or more kinds of inorganic layered compounds. Similarly, the second layer may contain one kind of inorganic layered compound or may contain two or more kinds of inorganic layered compounds. The inorganic layered compound contained in the first layer and the inorganic layered compound contained in the second layer may be the same or different.

The first layer contains components other than the inorganic layered compound. The component other than the inorganic layered compound is usually a resin, preferably a thermoplastic resin.

Examples of the resin contained in the first layer include polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), polyvinylidene chloride (PVDC), polyacrylonitrile (PAN), polysaccharides, polyacrylic acid and Examples thereof include esters and urethane resins. From the viewpoint of the gas barrier property of the multilayer structure, the resin contained in the first layer was measured for oxygen permeability under the condition of 23 ° C0% RH using a film having a thickness of 25 μm consisting only of the resin. In case of 1000cc / m²-A resin having a day / atm or less is preferable. When it is difficult to produce a film made of only a resin, a laminated film is formed by forming a layer made of a resin whose oxygen permeability is desired to be measured on a base film made of another resin having a known oxygen permeability. Prepare and measure the oxygen permeability of this laminated film. The oxygen permeability of the resin layer formed on the base film is determined by the following formula. 1 / P = (1 / P1) + (1 / P2) P: Oxygen permeability of laminated film (cc / m² Day atm) P1: Oxygen permeability of base film (cc / m² Day atm) P2: Oxygen permeability of resin layer (cc / m² Day atm) Specifically, a PET film having a thickness of 25 μm is used as the base film, a layer made of a resin whose oxygen permeability is to be measured is formed on the base film, and the oxygen permeability is measured, and the resin layer is 25 μm. Calculate the oxygen permeability per area.

Examples of the resin satisfying the above conditions of oxygen permeability include PVA, EVOH, PVDC, PAN, polysaccharides, polyacrylic acid and its esters, polyamide, polyester, and urethane-based resin.

Examples of the urethane-based resin include known one-component curable urethane-based resins and two-component curable urethane-based resins obtained by reacting a polyol with an isocyanate compound. Polysaccharides are biopolymers synthesized in a biological system by polycondensation of various monosaccharides, and here, those chemically modified based on them are also included. For example, cellulose and cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose and carboxymethyl cellulose, amylose, amylopectin, pullulan, curdlan, zantane, chitin, chitosan and the like can be mentioned.

The resin contained in the first layer may be polyvinyl alcohol from the viewpoint of being easily dissolved in an aqueous dispersion medium, easy to handle, and the gas barrier property of the obtained multilayer structure. Most preferred. Polyvinyl alcohol is a polymer having a monomer unit of vinyl alcohol as a main component. Examples of such "polyvinyl alcohol" include polymers obtained by hydrolyzing the acetate ester portion of a vinyl acetate polymer (to be exact, a copolymer of vinyl alcohol and vinyl acetate, or trifluoroacetic acid. Examples thereof include polymers obtained by hydrolyzing a vinyl polymer, a vinyl formate polymer, a vinyl pivalate polymer, a t-butyl vinyl ether polymer, a trimethylsilyl vinyl ether polymer and the like (for details of "polyvinyl alcohol", for example, for example. "The World of PVA", edited by Poval Association, 1992, Polymer Publishing Association Co., Ltd .; Nagano et al., "Poval", 1981, Polymer Publishing Association Co., Ltd. can be referred to). The degree of "saponification" is preferably 70 mol% or more, more preferably 85 mol% or more, further preferably 98% mol or more of a so-called completely saponified product, and the degree of polymerization is 100 or more and 5000 or less and 200 or more and 3000. The following is more preferable.

The second layer may be composed of only the inorganic layered compound or may contain other components. Examples of the components other than the inorganic layered compound contained in the second layer include resins similar to those contained in the first layer. When the second layer contains a resin, the resin is preferably polyvinyl alcohol because it has excellent gas barrier properties and is easy to handle.

In the multilayer structure of the present invention, the second layer is laminated adjacent to the first layer. The volume fraction of the inorganic layered compound in the second layer may be higher than the volume fraction of the inorganic layered compound in the first layer. Conventionally, it has been considered that the gas barrier property of a structure having a layer containing an inorganic layered compound becomes better as the volume fraction of the inorganic layered compound in the layer increases. If so, the gas barrier properties should be the same if the volume fractions of the inorganic layered compounds in the layer containing the inorganic layered compounds are the same. However, the volume fraction of the inorganic layered compound is different from that of the multilayer structure of the present invention in which the first layer and the second layer having different volume fractions of the inorganic layered compound are laminated adjacent to each other as in the present invention. Average volume fraction of the inorganic layered compound in the first layer and the second layer ((((volume of the inorganic layered compound contained in the first layer + volume of the inorganic layered compound contained in the second layer)) / Comparing with a structure having one layer equal to (volume of the first layer + volume of the second layer)) × 100), the multilayer structure of the present invention has a gas barrier property under high humidity conditions. It became clear that it was excellent.

From the viewpoint of gas barrier properties under high humidity conditions, the volume fraction of the inorganic layered compound in the second layer is 70 to 100 vol%, and 10 vol% or more from the volume fraction of the inorganic layered compound in the first layer. High is preferable. The volume fraction of the inorganic layered compound in the second layer is more preferably 75 vol% or more, further preferably 80 vol% or more, further preferably 90 vol% or more, and most preferably 100 vol%. preferable. By increasing the difference in the volume fractions of the inorganic layered compounds between the first layer and the second layer, it becomes easy to uniformly stack the second layer having a high volume fraction of the inorganic layered compounds, and the second layer. Adhesion between the layer and the first layer is improved. When the first layer and / or the second layer is coated and dried as described later, the volume of the inorganic layered compound relative to the volume of the residue obtained by removing the volatile components from the coating liquid used. The fraction is regarded as the volume fraction of the inorganic layered compound in each layer.

The volume fraction of the inorganic layered compound in the first layer is preferably less than 70 vol%, more preferably 5 to 50 vol%, further preferably 10 vol% or more, and 15 vol% or more. Is more preferable, and 20 vol% or more is most preferable. By setting the volume fraction of the inorganic layered compound in the first layer as described above, a multilayer structure having better gas barrier properties under high humidity conditions can be obtained. When the layer containing the inorganic layered compound is coated and dried as described later, the volume fraction of the inorganic layered compound in the first layer is 40 vol% or less from the viewpoint of coatability. It is more preferably 35 vol% or less, and most preferably 30 vol% or less.

The multilayer structure of the present invention may have a base material layer. The material constituting the base material layer is not particularly limited, and examples thereof include metal, resin, wood, ceramic, and glass. The form of the base material layer is also not particularly limited, and examples thereof include paper, cloth, non-woven fabric, and film. As the resin, a thermoplastic resin or a thermosetting resin can be used. When the multilayer structure of the present invention is used as a packaging material, it is preferable that the base material layer is made of a thermoplastic resin. The thermoplastic resins used include low-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, and ethylene-octene copolymer. , Polypropylene (PP), ethylene-vinyl acetate copolymer, ethylene-methylmethacrylate copolymer, polyolefin resin such as ionomer resin, polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, nylon-6 ( Ny-6), Nylon-6, 6. Metaxylene diamine-adipic acid reduced polymer, amide resin such as polymethylmethacrylimide, acrylic resin such as polymethylmethacrylate, polystyrene, styrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene copolymer, poly Styrene-acrylonitrile-based resins such as acrylonitrile, hydrophobic cellulose-based resins such as cellulose triacetate and cellulose diacetate, halogen-containing resins such as polyvinyl chloride, polyvinylidene chloride, and vinylidene fluoride, polyvinyl alcohol, and ethylene-vinyl alcohol co-weight. Examples thereof include hydrogen-bonding resins such as coalescing and cellulose derivatives, polycarbonate resins, polysulfone resins, polyether sulfone resins, polyether ether ketone resins, polyphenylene oxide resins, and polymethylene oxide resins. Examples of the thermosetting resin include known phenol resins, melamine resins, urea resins and the like. When the multilayer structure of the present invention is a film, the base material layer may be any of non-stretched film, uniaxially stretched film, and biaxially stretched film, but any of polypropylene, polyester resin, and amide resin. It is preferably a biaxially stretched film made of. The base material layer may be a multilayer film such as Ny-6 / MXD6-Ny / Ny-6 or PP / EVOH / PP, or a film on which aluminum, alumina, or silica is vapor-deposited.

The base material layer may be laminated adjacent to the first layer or the second layer containing the inorganic layered compound, and may be laminated with the first layer or the second layer via another layer such as an adhesive layer. It may be laminated. As will be described later, when the first layer or the second layer is formed on the base material layer by coating, a multilayer structure in which the first layer is laminated on the base material from the viewpoint of coatability. It is preferably a body. The first layer may be provided on one side or both sides of the base material layer, or may be provided on a part or the entire surface of the base material layer.

The multilayer structure of the present invention may have a layer other than the first layer, the second layer and the base material layer. Further, a plurality of layers having the same composition as the first layer and the second layer may be provided. When the multilayer structure of the present invention includes a base material layer, the configuration thereof is, for example, Base material layer / first layer / second layer (constituent 1), Substrate layer / first layer / second layer / additional layer A containing an inorganic layered compound (Structure 2), Base material layer / first layer / second layer / additional layer B containing an inorganic layered compound / additional layer C containing an inorganic layered compound (Structure 3), Substrate layer / First layer / Second layer / Additional layer containing inorganic layered compound D / Additional layer containing inorganic layered compound E / Additional layer F containing inorganic layered compound (Structure 4), Base material layer / first layer / second layer / resin layer (constituent 5), Base material layer / 1st layer / 2nd layer / Additional layer containing inorganic layered compound B / Additional layer containing inorganic layered compound C / Resin layer (Structure 6), Base material layer / First layer / Second layer / Additional layer containing inorganic layered compound D / Additional layer containing inorganic layered compound E / Additional layer containing inorganic layered compound F / Resin layer (Structure 7) Can be mentioned. Here, the additional layers A, B, C, D, and E containing the inorganic layered compound may have the same composition as the first layer or the second layer, respectively. For example, in the configuration 2, the additional layer A containing the inorganic layered compound may have the same composition as the first layer, and in the configuration 3, the additional layer B containing the inorganic layered compound contains the first layer and the inorganic layered compound. Layer C may have the same composition as the second layer. Further, in the configuration 4, the additional layers D and F containing the inorganic layered compound may have the same composition as the first layer, and the additional layer E containing the inorganic layered compound may have the same composition as the second layer.

When the multilayer structure of the present invention is boiled or retorted, the volume fraction of the inorganic layered compound in the outermost layer is preferably 60 to 100 vol%, more preferably 70 vol% or more, and 80 vol% or more. Is even more preferable, 90 vol% or more is even more preferable, and 100 vol% is most preferable. When the volume fraction of the inorganic layered compound in the outermost layer is within the above range, the multi-layer structure is difficult to whiten after boiling or retort treatment, that is, has excellent whitening resistance. When the multilayer structure of the present invention is used in an application requiring whitening resistance, the outermost layer thereof may have the same composition as the first layer or the second layer. Further, the second layer may be the outermost layer. For example, when the volume fraction of the inorganic layered compound in the second layer is 60 vol% or more, the composition may be a base material layer / first layer / second layer, and the base material layer / first layer. Layer / second layer / (a layer in which the volume fraction of the inorganic layered compound is 50 to 100 vol% and the composition is different from that of the second layer) may be used.

Further, when the multilayer structure of the present invention is used in an application requiring bending resistance, the body integration ratio of the inorganic layered compound in the outermost layer is preferably 0 to 50 vol%, more preferably 40 vol% or less. It is preferably 30 vol% or less, and more preferably 30 vol% or less. When the outermost layer does not contain an inorganic layered compound, the outermost layer is composed of only a resin or an additive other than the resin and the inorganic layered compound. Examples of the resin constituting the outermost layer include ethyleneimine-based resin, butadiene-based resin, urethane-based resin, acrylic-based resin, amide-based resin, and EVOH.

When the multilayer structure of the present invention is used in an application requiring bending resistance, the outermost layer thereof may have the same composition as the first layer or the second layer. For example, when the volume fraction of the inorganic layered compound in the second layer is 50 vol% or less, the composition may be such as a base material layer / a first layer / a second layer. When the volume fraction of the inorganic layered compound in the second layer is higher than 50 vol%, the volume fraction of the base material layer / first layer / second layer / inorganic layered compound is 0 to 50 vol%. With such a configuration, not only the gas barrier property under high humidity conditions but also the bending resistance is excellent. At this time, the volume fraction of the inorganic layered compound in the outermost layer may be the same as or different from that in the first layer.

The outermost layer of the multilayer structure of the present invention when the whitening resistance is excellent and the outermost layer of the multilayer structure of the present invention when the bending resistance is excellent are both laminated on at least the first layer. It suffices if it is provided on the second layer.

When the multilayer structure of the present invention is a film, it is preferable to have a heat seal layer. The resins constituting the heat seal layer include low density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, and ethylene-4-. Methyl-1-pentene copolymer, ethylene-octene copolymer, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer Examples thereof include a coalescence, a polyolefin resin such as an ionomer resin, a polyacrylonitrile resin, and a polyester resin. Further, even when the multilayer structure of the present invention is a container, it is preferable that the surface to be sealed with the lid material is a sealant layer.

The heat seal layer is usually laminated with the base material layer, but the laminating method is not particularly limited. For example, a method of co-extruding a heat seal layer and a base material layer, a method of applying a solution in which a resin constituting the heat seal layer is dissolved in a solvent to the base material layer, and then removing the solvent, a method of removing the solvent on the base material layer. Examples thereof include a method of extrusion laminating the resin constituting the heat seal layer, a method of dry laminating the heat seal layer and the base material layer, and the like. The laminated surface of the heat seal layer and the base material layer may be subjected to treatments such as corona treatment, ozone treatment, electron beam treatment, and coating of an anchor coating agent.

As a method for producing the multilayer structure of the present invention having a substrate layer, a method for producing the multilayer structure itself by coextrusion, a substrate layer previously molded by a known method such as an extrusion method or an injection molding method, and a substrate layer. Examples thereof include a method of adhering a laminate in which a first layer and a second layer are laminated in advance. Since the second layer having a high volume fraction and a thin thickness can be easily provided, the first coating liquid composed of the first liquid medium and the first material contained therein is used as a base. The liquid medium is coated on the material layer, and then the liquid medium is removed to form a first layer made of the first material on the base material layer, and the second liquid medium and the second contained therein are formed. A second coating liquid made of the above-mentioned material is applied onto the first layer, and then the liquid medium is removed to put the second layer made of the second material on the first layer. The method of forming is preferred.

The second coating liquid consists of a second liquid medium and a second material contained therein. The second material contains at least an inorganic layered compound. When preparing an inorganic layered compound coating solution containing an inorganic layered compound in a liquid medium like the second coating solution, high-pressure dispersion is performed using a high-pressure disperser from the viewpoint of dispersibility of the inorganic layered compound. It is preferable to process. Examples of the high-pressure disperser include an ultra-high pressure homogenizer manufactured by Microfluidics Corporation (trade name: Microfluidizer), a nanomizer manufactured by Nanomizer, a menton-gorin type high-pressure disperser, and a homogenizer manufactured by Izumi Food Machinery. The high-pressure dispersion treatment is performed by allowing the coating liquids to pass through a plurality of thin tubes at high speed and then merging them to cause the coating liquids containing the inorganic layered compounds to collide with each other or the coating liquid and the inner wall of the thin tubes. This is a treatment method that applies high shear and / or high pressure to the working solution. In the high-pressure dispersion treatment, the inorganic layered compound coating liquid is passed through a thin tube having a tube diameter of about 1 μm to 1000 μm, and at this time, 100 kgf / cm.²It is preferable to perform the treatment so that the above maximum pressure is applied. Maximum pressure is 500kgf / cm²More preferably, 1000 kgf / cm²The above is particularly preferable. Further, when the coating liquid containing the inorganic layered compound passes through the thin tube, the maximum reaching speed of the coating liquid is preferably 100 m / s or more, and the heat transfer rate due to pressure loss is 100 kcal / hr or more. Is preferable.

The first coating liquid comprises a first liquid medium and a first material contained therein. The first material contains at least an inorganic layered compound, and usually further contains a resin. Further, the second coating liquid may also contain a resin as the second material in addition to the inorganic layered compound. As described above, the coating liquid containing the resin and the inorganic layered compound can be adjusted by the following method. For example, a method of mixing a resin solution obtained by dissolving a resin or the like in a solvent and a coating liquid of an inorganic layered compound in which an inorganic layered compound is previously swollen and opened in a liquid medium, or an inorganic layered compound is preliminarily swollen in a liquid medium. Examples thereof include a method of directly mixing a resin or the like with the coating solution of the opened inorganic layered compound, and a method of mixing the resin solution and the inorganic layered compound. Since the sufficiently swollen and opened inorganic layered compound can be uniformly dispersed in the resin, the resin solution obtained by dissolving the resin or the like in a solvent and the inorganic layered compound that has been swollen and opened in advance in a liquid medium. A method of mixing with a coating solution of a layered compound is preferable. When preparing a coating liquid containing a resin and an inorganic layered compound, the liquid containing the resin and the inorganic layered compound may be subjected to the above-mentioned high-pressure dispersion treatment, or the coating liquid of the inorganic layered compound previously subjected to the high-pressure dispersion treatment. And the resin may be mixed by the method described above.

The resin contained in the first coating liquid and / or the second coating liquid is a hydrogen bonding group such as a hydroxyl group, an amino group, a thiol group, a carboxyl group, a sulfonic acid group, or a phosphoric acid group, a carboxylate group, or a sulfone. In the case of a resin having a crosslinkable reactive group such as an acid ion group, a phosphate ion group, an ammonium group, a phosphonium group or the like, a crosslinking agent may be added to the coating liquid. Examples of the cross-linking agent used include titanium-based coupling agents, silane-based coupling agents, melamine-based coupling agents, epoxy-based coupling agents, isocyanate-based coupling agents, carbodiimide-based coupling agents, copper compounds, zirconium compounds, and the like. Can be mentioned. Only one type of these cross-linking agents may be used, or two or more types may be mixed and used as appropriate.

When a cross-linking agent is added to the coating liquid, the blending ratio of the resin and the cross-linking agent is the number of moles of the cross-linking functional group in the resin (that is, the total number of moles of the hydrogen-binding group and the ionic group). Assuming that the number of moles of the cross-linking forming group containing the ligand in the cross-linking agent is CN, the ratio of the number of moles of the cross-linking forming group in the cross-linking agent to the number of moles of the cross-linking functional group in the resin K (K = CN /) The HN) is preferably blended so as to be 0.001 to 10, and more preferably 0.01 to 1. If the blending ratio of the cross-linking agent is too small, the effect of improving the water resistance is not sufficient, and if it is too large, the coating liquid tends to gel. When the cross-linking agent is added to the coating liquid, a cross-linking agent solution in which the cross-linking agent is dissolved in a solvent such as alcohol in advance in an amount of 10 to 90% by weight is usually added to the coating liquid containing an inorganic layered compound and a resin. Adjusted by method. When a chelate compound is used as the cross-linking agent, the coating liquid is preferably acidic, more preferably pH 5 or less, and more preferably pH 5 or less, from the viewpoint of stability of the coating liquid after mixing the cross-linking agent. The following is particularly preferable. There is no particular lower limit to the pH of the coating liquid, but it is usually 0.5 or higher. It can be made acidic by adding an acidic solution such as hydrochloric acid to the coating liquid or by ion-exchange treatment of the coating liquid.

It is preferable to add a surfactant to the first coating liquid and / or the second coating liquid. By applying a first coating solution and / or a second coating solution containing a surfactant to form a first layer and / or a second layer, the layer and / or adjacent to the layer. Adhesion with the layer can be improved. The content of the surfactant is usually 0.001 to 5% by weight in 100% by weight of the coating liquid. If the amount of the surfactant added is too small, the effect of improving the adhesiveness is not sufficient, and if the amount of the surfactant added is too large, the barrier property may be lowered.

As the surfactant, known surfactants such as anionic surfactants, cationic surfactants, amphoteric ionic surfactants and nonionic surfactants can be used. In particular, ether-type nonionic surfactants (silicone-based nonionic surfactants) such as alkali metal salts of carboxylic acids having an alkyl chain having 6 or more carbon atoms and 24 or less carbon atoms and polydimethylsiloxane-polyoxyethylene copolymers. ) And a fluorine-type nonionic surfactant (fluorine-based nonionic surfactant) such as a perfluoroalkylethylene oxide compound are preferably used from the viewpoint of improving adhesion.

The first coating liquid composed of the first liquid medium and the first material contained therein and the second coating liquid composed of the second liquid medium and the second material contained therein are described above. The requirement that the ratio of the dry body liquid of the second inorganic layered compound to the dry volume of the second material is higher than the ratio of the dry volume of the first inorganic layered compound to the dry volume of the first material. Fulfill. Here, the dry volume of the first material and the dry volume of the second material are the volumes of the first or second material when the liquid medium is removed from each coating liquid. For example, when the coating liquid contains an inorganic layered compound and a resin as materials, it is the total volume of the inorganic layered compound and the resin. The dry volume is the volume of each layer of the multilayer structure, but since each layer is usually formed by completely removing the liquid medium, the volume of the material contained in each coating liquid used to form each layer is used. It may be regarded as the dry volume. When the coating liquid contains a surfactant or a cross-linking agent, these are usually in a small amount, so that the dry volume can be regarded as the total volume of the inorganic layered compound and the resin.

It is preferable that the multilayer structure of the present invention is heat-treated in advance at 110 ° C. or higher and 220 ° C. or lower before use from the viewpoint of improving the gas barrier property after hot water treatment such as boiling or retort. The heat source used for the heat treatment is not particularly limited, and various methods such as heat roll contact, heat medium contact (air, etc.), infrared heating, microwave heating, and the like can be applied. The heat treatment time is usually within 48 hours.

The base material layer is preliminarily subjected to surface treatment such as corona treatment, ozone treatment, ion treatment, frame treatment using a gas such as silane, normal pressure or reduced pressure plasma treatment when laminating this layer with other layers. May be good. Further, an anchor coat layer may be provided on the surface of the base material layer. The anchor coat layer can be formed by using a known ethyleneimine-based, two-component curable urethane-based anchor coat agent, or the like.

As a method of providing the anchor coat layer, the first layer, and the second layer by coating, a gravure method such as a direct gravure method and a reverse gravure method, a roll such as a two-roll beat coat method and a roll such as a bottom feed three reverse coat method. Examples include a coating method, a doctor knife method, a die coating method, a bar coating method, a dipping method, and a spray coating method. Further, the above-mentioned additional layer and resin layer can also be provided by the same method. When the multilayer structure is a film, it is preferable to adopt the gravure method because a layer having a uniform thickness can be provided.

The thickness of each layer constituting the multilayer structure of the present invention is not particularly limited. The thickness of the first layer and the second layer is usually 1 nm to 10 μm from the viewpoint of gas barrier property and cost. From the viewpoint of bending resistance, the thickness of the second layer is preferably thinner than the thickness of the first layer. The thickness of the additional layer and the resin layer described above is usually 1 nm to 10 μm. When the anchor coat layer is provided on the base material layer, the thickness of the anchor coat layer is usually 0.01 to 5 μm.

Each layer constituting the multilayer structure of the present invention may contain various additives such as an ultraviolet absorber, a colorant, and an antioxidant, if necessary, to the extent that the effects of the present invention are not impaired.

The multilayer structure of the present invention includes optical component members such as substrates for flexible displays such as tires and screws, liquid crystal displays and organic EL, or encapsulants, substrates such as solar cells or dye-sensitized solar cells, and encapsulants. Such as electronic component members and the like. For example, a coated screw obtained by laminating a first layer and a second layer on a metal screw is not easily deteriorated by oxygen. In this way, by laminating the first layer and the second layer on various conventional products that do not have the first layer and the second layer to form the multilayer structure of the present invention, deterioration due to conventional oxygen It is possible to suppress the oxygen deterioration of the product, which has been a problem. It can also be used as a vacuum heat insulating panel. Further, by using the multilayer structure of the present invention as a packaging material, it is possible to prevent oxygen deterioration of the contents packaged with the packaging material. When the multilayer structure of the present invention is used as a packaging material, its shape includes a film, a bag, a pouch, a bottle, a bottle cap, a carton container, a cup, a plate, a tray, a tank, a tube and the like. When the volume fraction of the inorganic layered compound in the outermost layer of the multilayer structure of the present invention is 60 to 100 vol%, it is excellent in whitening resistance after boiling or retort, and therefore, as a packaging material for boiling or retort. It is preferably used. The contents packaged by the multilayer structure of the present invention include cakes, Western confectionery such as castella, Japanese confectionery such as Daifuku and mochi, confectionery such as snack confectionery such as potato chips, processed marine products such as chikuwa and kamaboko, and miso. Examples include foods such as pickles, kamaboko, meat balls, hamburgers, hams and sausages, beverages such as coffee, tea and juice, dairy products such as milk and yogurt, rice and curry. In addition to food products, toiletry products such as detergents, bath salts, and cosmetics, fuels such as gasoline and hydrogen gas, powders, tablets, eye drops, pharmaceuticals and medical devices such as infusion bags, electronic parts such as hard disks and silicon wafers, and electronic parts. It can also be used as a packaging material for electronic devices and the like.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. The methods for measuring various physical properties are described below.

[Thickness measurement] The thickness of 0.5 μm or more was measured using a commercially available digital thickness gauge (contact type thickness gauge, trade name: ultra-high precision decimicrohead MH-15M, manufactured by Nippon Kogaku Co., Ltd.). The thickness of less than 0.5 μm was determined by cross-sectional observation of a transmission electron microscope (TEM).

[Measurement of particle size] The measurement was performed using a laser diffraction / scattering type particle size distribution measuring device (LA910, manufactured by HORIBA, Ltd.). The inorganic layered compound coating solution was diluted, the average particle size of the inorganic layered compound in the diluted solution was measured with a flow cell with an optical path length of 4 mm, and the obtained average particle size was defined as the average particle size L of the inorganic layered compound. I considered it. The average particle size of the inorganic layered compound in the coating solution was measured with a paste cell at an optical path length of 50 μm without diluting the inorganic layered compound coating solution, and the average particle size and the diluted solution were used to determine the average particle size. When the value of the average particle size L was substantially the same, it was determined that the inorganic layered compound was sufficiently swollen and opened in the coating liquid.

[Aspect ratio calculation] Using an X-ray diffractometer (XD-5A, manufactured by Shimadzu Corporation), the inorganic layered compound itself was diffracted by the powder method. As a result, the unit thickness a of the inorganic layered compound was obtained, and the aspect ratio Z was calculated by the formula Z = L / a using the particle size L obtained by the above method. X-ray diffraction measurement was also performed on the dried first coating liquid used for forming the first layer, and it was confirmed that the interplanar spacing of the inorganic layered compound was widened.

[Flex resistance test] Evaluated according to ASTM F392. After aging a 210 mm x 297 mm multilayer film in an environment of 23 ° C and 50% RH for 24 hours, the 210 mm sides are aligned to form a cylinder, and a gelboflex tester with a constant temperature bath (Tester Sangyo Co., Ltd.) is used. After twisting the tubular film by 440 ° with the central axis in the length direction as the rotation axis, the operation of returning to the original state was repeated 100 times.

[Boil processing] A multilayer film (210 mm × 300 mm) having a heat seal layer on one side, which was aged for 24 hours in an environment of 23 ° C and 50% RH, was folded in half with the heat seal layer inside. Using a heat sealer (FUJI IMPULSE T230: manufactured by FUJI IMPULSE CO.LTD), two sides were heat-sealed at a temperature of 150 ° C. for 1 second and a heat-sealing width of 10 mm to prepare a bag of 105 mm × 150 mm. 50 cc of water was put into this bag, and the remaining sides were heat-sealed in the same manner as before to form a sealed bag, and the sealed bag was boiled at 98 ° C for 60 minutes. After boiling, the bag was stored in a 23 ° C50% RH atmosphere for 24 hours, and then the appearance of the sealed bag was visually evaluated. : No bleaching Δ: Slight whitening ×: With bleaching

[Oxygen permeability measurement] Based on JIS K7126, measurement was performed with an ultrasensitive oxygen permeability measuring device (OX-TRANML, manufactured by MOCON) under the conditions of 23 ° C 90% RH or 23 ° C 50% RH.

[Preparation of coating liquid] (1) Preparation of the first coating liquid In a dispersion kettle (trade name: Despa MH-L, manufactured by Asada Iron Works Co., Ltd.), 1300 g of ion-exchanged water (specific electrical conductivity 0.7 μs / cm or less) and polyvinyl alcohol (PVA117H; manufactured by Kuraray Co., Ltd., Kenka) Degree; 99.6%, degree of polymerization 1,700) 130 g was mixed, and the temperature was raised to 95 ° C under low-speed stirring (1500 rpm, peripheral speed 4.1 m / min). The mixed system was stirred at the same temperature for 30 minutes to dissolve polyvinyl alcohol, and then cooled to 60 ° C. to obtain an aqueous polyvinyl alcohol solution. While stirring the polyvinyl alcohol aqueous solution (60 ° C.) under the same conditions as described above, an alcohol aqueous solution prepared by mixing 122 g of 1-butanol, 122 g of isopropyl alcohol and 520 g of ion-exchanged water was added dropwise over 5 minutes. After the dropping is completed, switch to high-speed stirring (3,000 rpm, peripheral speed = 8.2 m / min), gradually add 65 g of high-purity montmorillonite (trade name: Kunipia G; manufactured by Kunimine Kogyo Co., Ltd.) to the stirring system, and finish the addition. After that, stirring was continued at 60 ° C for 60 minutes. Then, 243 g of isopropanol was further added over 15 minutes, and then the mixed system was cooled to room temperature to obtain a first inorganic layered compound-containing solution. Nonionic surfactant (polydimethylsiloxane-polyoxyethylene copolymer, trade name: SH3746, manufactured by Toray Dow Corning Co., Ltd.) 0.1% by weight (containing above) with respect to this first inorganic layered compound-containing liquid. Add (based on the weight of the liquid), and use a high-pressure disperser (trade name: ultra-high pressure homogenizer M110-E / H, manufactured by Microfluidics Corporation) to add 1100 kgf / cm.²The first dispersion was obtained. The cleaved montmorillonite average particle size in the first inorganic layered compound dispersion was 560 nm, the a value obtained from powder X-ray diffraction was 1.2156 nm, and the aspect ratio was 460. To 1000 g of the above first dispersion, 1000 g of ion-exchanged water and 1000 g of isopropyl alcohol are added, and 2.66 g of titanium acetylacetonate (trade name: TC100, manufactured by Matsumoto Pharmaceutical Co., Ltd.) is added to this under low speed stirring ( The first coating solution was prepared by gradually adding the system at 1500 rpm and a peripheral speed of 4.1 m / min) while adjusting the pH of the system to 3 or less with hydrochloric acid. When the total volume of the polyvinyl alcohol and the inorganic layered compound in the first coating liquid was 100%, the volume fraction of the inorganic layered compound was 20 vol%.

(2) Preparation of the second coating liquid At room temperature, 1000 g of ion-exchanged water and 1000 g of isopropanol were stirred at high speed (3,000 rpm, peripheral speed = 8.2 m / min), and high-purity montmorillonite (trade name: Kunipia G; Kunimine Kogyo) was added to the stirring system. (Manufactured by Co., Ltd.) 12 g was gradually added, and after the addition was completed, stirring was continued for 60 minutes at room temperature. Then, hydrochloric acid was added to adjust the pH of the system to 3 or less, and a second coating liquid was prepared.

(3) Preparation of the third coating liquid A third coating liquid was prepared in the same manner as in the preparation of the first coating liquid, except that the amount of montmorillonite added was 122 g. The volume fraction of the inorganic layered compound was 32 vol% when the total volume of the polyvinyl alcohol and the inorganic layered compound in the third coating liquid was 100%.

(4) Preparation of the fourth coating liquid A fourth coating liquid was prepared in the same manner as in the preparation of the first coating liquid, except that the amount of montmorillonite added was 111 g. The volume fraction of the inorganic layered compound was 30 vol% when the total volume of the polyvinyl alcohol and the inorganic layered compound in the fourth coating liquid was 100%.

[Example 1] A 15 μm-thick biaxially stretched nylon (ONy) film (trade name: ON-U; manufactured by Unitica Co., Ltd.) was corona-treated on one side as a base material layer, and the corona-treated surface of the base material layer was described above. Micro gravure coating method (number of gravure roll lines) using a test coater (manufactured by Yasui Seiki) for the first coating liquid of By 300), gravure coating was performed at a coating speed of 3 m / min and dried at a drying temperature of 100 ° C. to form a first layer containing an inorganic layered compound. The thickness of the first layer was 0.04 μm. The first layer is referred to as an A1 layer. Next, the second coating liquid was applied onto the A1 layer in the same manner as the first coating liquid and dried to form a second layer containing the inorganic layered compound. The second layer is referred to as a B1 layer. Further, the first coating liquid was applied onto the B1 layer in the same manner as before and dried to form the A2 layer. Next, a second coating liquid was applied onto the A2 layer in the same manner and dried to form the B2 layer. Finally, the coating liquid 1 was applied to the B2 layer and dried to form the A3 layer. In this way, the first coating liquid is applied three times and the second coating liquid is applied twice alternately, and 6 layers (base material layer / A1 layer / B1 layer / A2 layer) including the base material layer are applied. / B2 layer / A3 layer) multi-layer structure was obtained. The total thickness of the layers containing the inorganic layered compound after drying in the multilayer structure, that is, the thickness of the A1 layer / B1 layer / A2 layer / B2 layer / A3 layer was 0.14 μm. The volume fraction of the inorganic layered compound in each of the A1, A2, and A3 layers is equal to the volume fraction of the inorganic layered compound with respect to the total volume of the polyvinyl alcohol and the inorganic layered compound in the first coating liquid used. It can be regarded as 20 vol%. The volume fraction of the inorganic layered compound in each of the B1 layer and the B2 layer was 100 vol%. Since the thickness of the A1 layer was 0.04 μm, the thickness of the A2 layer and the A3 layer coated under the same conditions was 0.04 μm, respectively, and the total thickness of the layers containing the inorganic layered compound was 0.14 μm. Therefore, the thickness of the B1 layer and the B2 layer was determined to be 0.01 μm, respectively. The average volume fraction of the inorganic layered compounds in the A1, B1, A2, B2, and A3 layers was 32 vol%. Oxygen permeability measurement, boil test, and bending resistance test were performed on the obtained multilayer structure, and the results are shown in Table 1.

[Example 2] A multilayer structure was obtained in the same manner as in Example 1 except that the A3 layer was not provided. The structure of the obtained multilayer structure is a base material layer / A1 layer / B1 layer / A2 layer / B2 layer, and the total thickness of the layers containing the inorganic layered compound after drying, that is, A1 layer / B1 layer / A2 layer. The thickness of the / B2 layer was 0.10 μm. The volume fraction of the inorganic layered compound in each of the A1 layer and the A2 layer was 20 vol%. The volume fraction of the inorganic layered compound in each of the B1 layer and the B2 layer was 100 vol%. The average volume fraction of the inorganic layered compounds in the A1, B1, A2, and B2 layers was 36 vol%. Oxygen permeability measurement, boil test, and bending resistance test were performed on the obtained multilayer structure, and the results are shown in Table 1.

[Example 3] A multilayer structure was obtained in the same manner as in Example 1 except that the fourth coating liquid was used instead of the first coating liquid. The structure of the obtained multilayer structure is a base material layer / D1 layer / B1 layer / D2 layer / B2 layer / D3 layer, and the total thickness of the layer containing the inorganic layered compound after drying, that is, the D1 layer / B1 layer. The thickness of the / D2 layer / B2 / D3 layer was 0.14 μm. The volume fraction of the inorganic layered compound in each of the D1 layer, D2 layer, and D3 layer was 30 vol%. The volume fraction of the inorganic layered compound in each of the B1 layer and the B2 layer was 100 vol%. The average volume fraction of the inorganic layered compounds in the D1, B1, D2, B2, and D3 layers was 43 vol%. Oxygen permeability was measured for the obtained multilayer structure, and the results are shown in Table 1.

[Comparative Example 1] A multilayer structure was obtained in the same manner as in Example 1 except that the first coating liquid was used instead of the second coating liquid. The structure of the obtained multilayer structure was a base material layer / A1 layer, and the thickness of the A1 layer after drying was 0.20 μm. The volume fraction of the inorganic layered compound in the A1 layer was 20 vol%. Oxygen permeability measurement, boil test, and bending resistance test were performed on the obtained multilayer structure, and the results are shown in Table 1. [Comparative Example 2] A multilayer structure was obtained in the same manner as in Example 1 except that the second coating liquid was used instead of the first coating liquid. The structure of the obtained multilayer structure was a base material layer / B1 layer, and the thickness of the B1 layer after drying was about 0.05 μm. However, the B1 layer was not sufficiently adhered to the base material layer and was easily peeled off, and when touched by hand, the inorganic layered compound adhered to the hand. The volume fraction of the inorganic layered compound in the B1 layer was 100 vol%. Oxygen permeability measurement and bending resistance test were performed on the obtained multilayer structure, and the results are shown in Table 1.

[Comparative Example 3] A C1 layer was provided on the base material in the same manner as in Example 2 except that the third coating liquid was used instead of the first coating liquid and the second coating liquid to obtain a multilayer structure. It was. The structure of the obtained multilayer structure was a base material layer / C1 layer, and the thickness of the C1 layer after drying was about 0.14 μm. The volume fraction of the inorganic layered compound in the C1 layer was 32 vol%. Oxygen permeability was measured for the obtained multilayer structure, and the results are shown in Table 1.

[Comparative Example 4] Oxygen permeability at 23 ° C × 90% RH of a multilayer structure in which a layer of 0.10 μm thick composed of an inorganic layered compound having a volume fraction of 36 vol% and polyvinyl alcohol is laminated on a base material layer. Was calculated using the following Nielsen theoretical formula, and it was 4.8cc / m.² It becomes day atm. Method of calculation Nielsen's formula (LAWRENCE E. NIELSEN, Models for the Permeability of Filled Polymer Systems, J. MACROMOL. SCI. (CHEM.), 1967, A1 (5), 929-942) P / P0 = (1-Φ) / (1 + AΦ / 2) Gas permeability of P: system P0: Resin gas permeability A: Aspect ratio of inorganic layered compound Φ: Volume fraction of inorganic layered compound The aspect ratio A of the inorganic layered compound is 460 (constant). The resin is polyvinyl alcohol, and the gas permeability P0 of the resin is constant. Then, the gas permeability P of the system can be expressed as a function of only the inorganic layered compound Φ. When the volume fraction Φ of the inorganic layered compound is 32 vol%, P (32vol%) = 0.0091 P0 When the volume fraction Φ of the inorganic layered compound is 36 vol% P (36vol%) = 0.00076 P0 Therefore, the oxygen permeability when the volume fraction of the inorganic layered compound is 36 vol% is 0.0076 / 0.0091, which is the oxygen permeability of 32 vol%. From Comparative Example 3, the oxygen permeability when the volume fraction of the inorganic layered compound is 32 vol% is 4.1 cc / m.²-Since it is day-atm, the oxygen permeability when the volume fraction of the inorganic layered compound is 36 vol% is 3.4 cc / m.² Calculated as day / atm. The gas permeability is inversely proportional to the thickness of the gas barrier layer. The above values are for a layer thickness of 0.14 μm. The same as in Example 2, the oxygen permeability when the thickness is 0.10 μm is 4.8 cc / m.² It is required as day / atm. [Comparative Example 5] Oxygen permeability at 23 ° C × 90% RH of a multilayer structure in which a layer of 0.14 μm thick composed of an inorganic layered compound having a volume fraction of 43 vol% and polyvinyl alcohol is laminated on a base material layer. Is calculated in the same manner as in Comparative Example 4, 2.6cc / m.² It becomes day atm.

<tables num="1"><img file="JP4929675B2_D0001.tif" /></tables>