JP5076799B2 - Method for producing multilayer structure - Google Patents

Description

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

  Conventionally, molded articles made of thermoplastic resins such as polypropylene, polyester and polyamide are used in many fields such as food, cosmetics, agricultural chemicals and medical fields due to their excellent mechanical properties, heat resistance and transparency. Widely used as packaging material. In the case where 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 a synthetic hectorite that is an inorganic layered compound is laminated on a base film. .

Japanese Patent Laid-Open No. 03-30944

  However, as described above, the packaging material having one layer containing the inorganic stratiform compound has insufficient gas barrier properties under high humidity conditions.

  The present invention provides a method for producing a multilayer structure having excellent gas barrier properties under high humidity conditions.

That is, this invention is a manufacturing method of the multilayer structure which has a base material layer, a 1st layer, and a 2nd layer adjacent on this 1st layer, Comprising: The following process (1), ( 2) in order.
(1) A first coating liquid containing a first inorganic layered compound, a first metal alkoxide, and a first aqueous medium is applied onto a base material layer to form a first coating film, and then Removing the first aqueous medium from the first coating film to form a first layer (2) a second containing a second inorganic layered compound, a second resin and a second liquid medium The coating liquid is applied onto the first layer to form a second coating film, and then the second liquid medium is removed from the second coating film to obtain the second layer. Forming on the first layer

  According to the method for producing a multilayer structure of the present invention, a multilayer structure having excellent gas barrier properties under high humidity conditions can be produced.

The present invention is a method for producing a multilayer structure having a base material layer, a first layer, and a second layer adjacent on the first layer, the following steps (1), (2 ) In order.
(1) A first coating liquid containing a first inorganic layered compound, a first metal alkoxide, and a first aqueous medium is applied onto a base material layer to form a first coating film, and then Removing the first aqueous medium from the first coating film to form a first layer (2) a second containing a second inorganic layered compound, a second resin and a second liquid medium The coating liquid is applied onto the first layer to form a second coating film, and then the second liquid medium is removed from the second coating film to obtain the second layer. Forming on the first layer

  First, the first coating liquid will be described. The first coating liquid contains a first inorganic layered compound, a first metal alkoxide, and a first aqueous medium.

As the first inorganic layered compound, a clay mineral having a swelling property to a solvent and a cleavage property is preferably used.
The inorganic layered compound of the present invention refers to a product in which unit crystal layers are stacked to form a layered structure in a raw material state. A layered structure is a structure in which atoms that are strongly bonded by a covalent bond or the like and densely arranged are stacked almost in parallel by a weak binding force such as van der Waals.
Among inorganic layered compounds, clay minerals having swelling property to a solvent are particularly preferably used.

  Clay minerals generally include (i) a type having a two-layer structure having an octahedral layer with aluminum, magnesium, etc. as a central metal above the silica tetrahedral layer, and (ii) the silica tetrahedral layer is made of aluminum. And a type having a three-layer structure in which an octahedral layer having a central metal such as magnesium is sandwiched from both sides. Examples of the two-layer structure type viscosity mineral (i) include clay minerals such as kaolinite group and antigolite group. Examples of the clay mineral of the three-layer structure type (ii) include clay minerals such as 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, beidellite, nontronite, saponite, sauconite, stevensite, hectorite, tetrasilic mica, sodium tenio. Light, muscovite, margarite, talc, vermiculite, phlogopite, xanthophyllite, chlorite and the like. In addition, these clay minerals treated with organic substances such as ion exchange and improved dispersibility (see Asakura Shoten, “Encyclopedia of Clay”; hereinafter may be referred to as organically modified clay minerals) are also used as inorganic layered compounds. Can be used. As said organic substance which processes a clay mineral, quaternary ammonium salts, such as a dimethyl distearyl ammonium salt and a trimethyl stearyl ammonium salt, a phosphonium salt, an imidazolium salt, etc. can be used.

  Among the clay minerals, smectite group, vermiculite group and mica group clay minerals are preferable, and smectite group is particularly preferable. Examples of the smectite group include montmorillonite, beidellite, nontronite, saponite, soconite, stevensite, and hectorite. In particular, montmorillonite is preferably used.

  The aspect ratio of the inorganic layered compound is not particularly limited, but 200 to 3000 is preferably used. When the aspect ratio of the inorganic layered compound is too small, the gas barrier property tends to be insufficient, and when 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 preferably has an average particle size of 5 μm or less. If the average particle size is too large, gas barrier properties, transparency and film-forming properties tend to be inferior, and in applications where transparency is required, it is preferably 1 μm or less.

  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 diameter of the inorganic layered compound, a is the unit thickness of the inorganic layered compound, that is, the thickness of the unit crystal layer of the inorganic layered compound, and is determined by the powder X-ray diffraction method (“instrumental analysis”). No. (a) "(1985, published by Kagaku Dojinsha, supervised by Jiro Shiokawa, p. 69).

  The average particle diameter of the inorganic layered compound is a particle diameter (volume-based median diameter) obtained 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 above diffraction / scattering pattern from the diffraction / scattering pattern obtained when light is passed through the dispersion of the inorganic layered compound by 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 diameter is determined for each section, and the particle size distribution, which is originally a continuous quantity, is converted into a discrete quantity and calculated. A method is mentioned. When the inorganic layered compound is sufficiently swollen and cleaved with a liquid medium of the same type as the liquid medium used for obtaining the average particle size of the inorganic layered compound by the diffraction / scattering method, the inorganic layered compound is mixed with a metal alkoxide or the like. The particle size of the swollen and cleaved inorganic layered compound in the layer formed using the liquid containing the layered compound can be regarded as approximately equal to the particle size of the inorganic layered compound measured in the liquid medium.

  Specifically, the inorganic layered compound preferably has a swelling value of 5 or more, more preferably a swelling value of 20 or more according to the following swellability test. Further, those having a cleavage value of 5 or more by cleavage test described below are preferred, and those having a cleavage value of 20 or more are more preferred.

(Swellability test)
Into a 100 ml graduated cylinder, 100 ml of liquid medium is added, and 2 g of inorganic layered compound is gradually added thereto. After standing at 23 ° C. for 24 hours, the volume (ml) of the inorganic layered compound dispersion layer is read from the scale of the interface between the inorganic layered compound dispersion layer and the supernatant in the graduated cylinder. It shows that swelling property is so high that this numerical value (swelling value) is large.

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

  One type of inorganic layered compound may be sufficient as a 1st inorganic layered compound, and two or more types may be sufficient as it.

The first coating liquid contains a first metal alkoxide. The first metal alkoxide used in the present invention is represented by the following general formula (I).
R ′ _m −M (−OR) _n (I)
(In the formula, M represents a metal element, and R ′ may be the same or different, and represents a reactive organic functional group represented by an amino group, an epoxy group, a vinyl group, a methacryl group, or a mercapto group, or an alkyl group. Represents a representative non-reactive organic functional group, R may be the same or different and represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, m is 0 or a positive integer, and n is 1 or more And m + n agrees with the valence of the metal element M.)

  Specific examples of the first metal alkoxide include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, propyltrimethoxysilane, and isopropyl. Trimethoxysilane, butyltrimethoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, ethyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldiisopropoxysilane, Dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldiisopropoxysilane, diethyldibutoxysilane, vinyl Methoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, glycidoxymethyltrimethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycyl Sidoxypropyltributoxysilane, (3,4-epoxycyclohexyl) methyltripropoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- (3,4-epoxycyclohexyl) propyltrimethoxysilane, Aminomethyltriethoxysilane, 2-aminoethyltrimethoxysilane, 1-aminoethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-aminomethylaminomethoxy Rutrimethoxysilane, N-aminomethyl-3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, N-β- (N -Vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, etc. Alkoxysilanes, titanium tetraethoxide, titanium tetraisopropoxide, titanium tetrabutoxide and other titanium alkoxides, zirconium tetraethoxide, zirconium tetraisopropoxide, zirco Zirconium alkoxides such as nitrotetrabutoxide, aluminum triethoxide, aluminum triisopropoxide, aluminum alkoxides such as aluminum tributoxide, and the like are preferable, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β -(3,4-epoxycyclohexyl) ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriisopropoxysilane, β- (3,4-epoxycyclohexyl) ethylmethyldimethoxysilane, β- (3, 4-epoxycyclohexyl) ethylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriisopropoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-isocyanopropyltrimethoxysilane, γ-isocyanopropyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane , Γ- (meth) acryloxypropyltriethoxysilane and the like are also exemplified as preferable examples.

  The metal represented by M in the general formula (I) is preferably Ti, Zr, Al, or Si. In particular, an alkoxide of Al or Si is preferable, and an alkoxide of Si is most preferable. The most preferred metal alkoxide is tetramethoxysilane or tetraethoxysilane.

Since the first metal alkoxide has a (—OR) group which is a hydrolyzable group, mixing with an aqueous medium such as water or alcohol causes all or part of the metal alkoxide to undergo hydrolysis. To produce a metal alkoxide hydrolyzate. Further, all or a part of the metal alkoxide hydrolyzate undergoes condensation polymerization after hydrolysis to produce a metal alkoxide hydrolysis polycondensate. In addition, when m in the general formula (I) is greater than 1 and R ′ is the reactive organic functional group, a reaction between the reactive organic functional group and the metal alkoxide hydrolyzate may occur. The first layer in the present invention contains at least one of a metal alkoxide, a metal alkoxide hydrolyzate, and a metal alkoxide hydrolysis polycondensate, and is usually a mixture thereof.

In the multilayer structure obtained by the method of the present invention, the first metal alkoxide is preferably reacted to form a metal alkoxide hydrolysis polycondensate from the viewpoint of barrier properties. Increasing the amount of metal alkoxide hydrolysis polycondensate contained in the first layer by containing a metal alkoxide hydrolysis catalyst in the first coating solution and actively hydrolyzing it, followed by polycondensation reaction Can be made. In order to advance a hydrolysis reaction or a polycondensation reaction, it can also heat. A known catalyst can be used as the hydrolysis catalyst. For example, inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, organic phosphoric acid, formic acid, acetic acid, acetic anhydride, chloroacetic acid, propionic acid, butyric acid, valeric acid, citric acid, gluconic acid, succinic acid, tartaric acid, lactic acid, Examples include fumaric acid, malic acid, itaconic acid, oxalic acid, mucous acid, uric acid, barbituric acid, p-toluenesulfonic acid and other organic acids, acidic cation exchange resins, protonated layered silicates, and the like.

  The first aqueous medium used in the present invention is preferably an aqueous medium that swells and cleaves the inorganic layered compound to be used. Examples of the aqueous medium include water, alcohols (methanol, ethanol, propanol, isopropanol, ethylene glycol, diethylene glycol and the like), dimethylformamide, dimethyl sulfoxide, acetone and the like, and water, alcohol, and a water-alcohol mixture are particularly preferable.

  It is preferable to add a surfactant to the first coating liquid. By forming the first layer using the first coating liquid containing a surfactant, the adhesion between the layer and the adjacent 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.

  As the surfactant, a known surfactant such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant can be used. In particular, an alkali metal salt of a carboxylic acid having an alkyl chain of 6 to 24 carbon atoms, an ether type nonionic surfactant such as a polydimethylsiloxane-polyoxyethylene copolymer (silicone-based nonionic surfactant) Agent) and fluorine-type nonionic surfactants (fluorine-based nonionic surfactants) such as perfluoroalkylethylene oxide compounds are preferable from the viewpoint of improving adhesion between layers.

  The first coating liquid may further contain a component that is soluble in the first aqueous medium. The normally soluble component is a resin. Examples of such components include resins having a hydroxyl group and a carboxyl group, resins having a hydroxyl group, and compounds having an isocyanate group. Examples of the resin having a hydroxyl group include polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, carboxymethyl cellulose, and sodium alginate. Among these, it is preferable to use polyvinyl alcohol from the viewpoint of gas barrier properties. The compound containing isocyanate is a compound having two or more isocyanate groups (NCO groups) in the compound, and is typically tolylene diisocyanate, triphenylmethane triisocyanate, isophorone diisocyanate, tetra And monomers such as methylxylene diisocyanate, polymers and derivatives thereof.

  The first coating liquid contains a first inorganic layered compound, a first metal alkoxide, and a first aqueous medium. The first coating liquid can be adjusted by the following method. For example, a method of mixing a dispersion of a first inorganic layered compound obtained by swelling and cleaving a first inorganic layered compound in an aqueous medium in advance, and a mixed liquid obtained by mixing a first metal alkoxide with an aqueous medium, A method of directly mixing a first metal alkoxide with a dispersion of a first inorganic layered compound obtained by swelling and cleaving an inorganic layered compound in an aqueous medium in advance, a first metal alkoxide mixed solution and a first inorganic layered compound The method of mixing is mention | raise | lifted. When preparing the first coating liquid, the liquid containing the first metal alkoxide and the first inorganic layered compound may be subjected to a high-pressure dispersion treatment as described later, or a first high-pressure dispersion treatment previously performed. The dispersion liquid of the inorganic layered compound and the first metal alkoxide or the mixed liquid of the first metal alkoxide and the liquid medium may be mixed by the method described above.

  Next, the second coating solution will be described. The second coating liquid includes a second inorganic layered compound, a second resin, and a second liquid medium.

  As the second inorganic layered compound, the same compound as the first inorganic layered compound can be used. The first inorganic layered compound and the second inorganic layered compound may be the same or different.

  The 2nd coating liquid in this invention contains 2nd resin. As the second resin, polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), polyvinylidene chloride (PVDC), polyacrylonitrile (PAN), polysaccharides, polyacrylic acid and esters thereof, urethane type Although the resin can be mentioned, the second resin has a hydroxyl group from the viewpoint of being easily dissolved in an aqueous liquid medium and being easy to handle and gas barrier properties of the resulting multilayer structure. A resin is preferred. Examples of such a resin include PVA, EVOH, and cellulose.

  From the viewpoint of gas barrier properties of the multilayer structure obtained by the method of the present invention, the second resin is (i) a resin having a hydroxyl group and a second functional group capable of reacting with the hydroxyl group in one molecule, or (Ii) It is preferably a mixture of a resin having a hydroxyl group and a resin having a second functional group capable of reacting with the hydroxyl group. Hereinafter, the case of (i) and the case of (ii) may be collectively referred to as “resin component having a hydroxyl group and a second functional group”.

  The second functional group capable of reacting with the hydroxyl group is preferably a functional group capable of forming a covalent bond or an ionic bond with the hydroxyl group. Specific examples include polar groups such as a carboxyl group, an amino group, a sulfonic acid group, a carboxylate group, and an ammonium group.

Examples of the resin containing a hydroxyl group and a second functional group in one molecule include vinyl alcohol-acrylic acid copolymer, vinyl alcohol-methacrylic acid copolymer, vinyl alcohol-vinylamine copolymer, acrylic acid-vinylamine copolymer. And a methacrylic acid-vinylamine copolymer.

Examples of the resin having a second functional group capable of reacting with a hydroxyl group include polyacrylic acid, polymethacrylic acid, polyvinylamine, acrylic acid-methacrylic acid copolymer, vinylamine- (meth) acrylic acid copolymer, and the like. Can be mentioned.
When the second resin is a mixture of a resin having a hydroxyl group and a resin having a second functional group capable of reacting with a hydroxyl group, the resin having a hydroxyl group is polyvinyl alcohol, and the second resin capable of reacting with the hydroxyl group. The resin having two functional groups is preferably polyacrylic acid and / or polymethacrylic acid.

Polyvinyl alcohol is a polymer having a vinyl alcohol unit as a main component. Examples of such “polyvinyl alcohol” include polymers obtained by hydrolyzing the acetate portion of vinyl acetate polymers, vinyl trifluoroacetate polymers, vinyl formate polymers, vinyl pivalate polymers, t- Examples include polymers obtained by hydrolyzing butyl vinyl ether polymers, trimethylsilyl vinyl ether polymers, etc. (For details on “polyvinyl alcohol”, see, for example, “Poval World”, “PVA World”, 1992, Kokai Co., Ltd. Molecular publication society; Nagano et al., “Poval”, 1981, see Kobunshi Shuppankai). The degree of “saponification” of the ester portion of the polymer is preferably 70 mol% or more, more preferably 85 mol% or more, and more preferably 98% mol or more of a so-called completely saponified product. The degree of polymerization of the vinyl alcohol polymer used is more preferably 100 or more and 5000 or less, and 200 or more and 3000 or less.

Moreover, as polyvinyl alcohol, so-called polyvinyl alcohol derivatives having a functional group other than a hydroxyl group can also be used. Examples of functional groups other than a hydroxyl group include an amino group, a thiol group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a carboxylate group, Examples include sulfonate ion groups, phosphate ion groups, ammonium groups, phosphonium groups, silyl groups, siloxane groups, alkyl groups, allyl groups, fluoroalkyl groups, alkoxy groups, carbonyl groups, and halogen groups. A part of hydroxyl groups in PVA may be replaced with one or more of these functional groups.
The polyvinyl alcohol in the present invention may be a copolymer containing a vinyl alcohol unit and an α-olefin unit such as ethylene or propylene. When polyvinyl alcohol contains a vinyl alcohol unit and an α-olefin unit in one molecule, in the present invention, a resin having an α-olefin unit content of 20 mol% or less is referred to as PVA. Here, the α-olefin unit means a structural unit derived from an α-olefin.

  The polyacrylic acid in the present invention includes a partially neutralized polyacrylic acid. Polymethacrylic acid includes a partially neutralized polymethacrylic acid. The weight average molecular weights of polyacrylic acid and polymethacrylic acid are each preferably in the range of 2,000 to 10,000,000, more preferably 100,000 to 5,000,000.

The partially neutralized polyacrylic acid can be usually obtained by adding an alkali to an aqueous solution of polyacrylic acid. A desired degree of neutralization can be achieved by adjusting the amount ratio of polyacrylic acid and alkali. Moreover, the polyacrylic acid complete neutralized product can be converted into a partially neutralized product by ion exchange. Here, the degree of neutralization of polyacrylic acid is defined by the following equation. The partially neutralized polyacrylic acid preferably has a degree of neutralization of 0.1% to 20% from the viewpoint of gas barrier properties and transparency of the multilayer structure.
Degree of neutralization = (A / B) × 100
A: Number of moles of neutralized carboxyl group contained in 1 g of polyacrylic acid B: Number of moles of carboxyl group before neutralization contained in 1 g of polyacrylic acid The same applies to neutralized polymethacrylic acid It is.

  When the second resin is a resin component having a hydroxyl group and a second functional group, and the second functional group is a carboxyl group, the molar ratio of the hydroxyl group to the carboxyl group contained in the resin component is hydroxyl group: The carboxyl group is preferably 30:70 to 95: 5, more preferably 70:30 to 95: 5. From the viewpoint of gas barrier properties under high humidity conditions of the obtained multilayer structure, when the weight of the resin component is 100%, the total weight of hydroxyl groups and carboxyl groups contained in the resin component is 30 to 60%. It is preferable that it is 35 to 55%.

  The molar ratio of the hydroxyl group to the carboxyl group in the resin component can be determined by NMR method, IR method or the like. For example, in the case of the IR method, a calibration curve is obtained using a sample having a known molar ratio of hydroxyl group to carboxyl group, and the number ratio between the hydroxyl group and carboxyl group of the measurement sample can be calculated using this. When using vinyl alcohol homopolymer and acrylic acid monopolymer and / or methacrylic acid monopolymer, the number of moles of hydroxyl group and carboxyl group is obtained in advance from the weight, and the number ratio of hydroxyl group to carboxyl group is calculated. can do. Further, the total weight measurement of the hydroxyl group and carboxyl group contained in the resin component can be determined by NMR method, IR method, etc., as in the molar ratio. For example, in the IR method, a calibration curve is obtained for a polyol polymer having a known number of polyol units and a polycarboxylic acid polymer having a known number of polycarboxylic acid units, and using these calibration curves, a hydroxyl group in a measurement sample is obtained. And the total weight of carboxyl groups can be calculated. Moreover, when using a vinyl alcohol single polymer and an acrylic acid single polymer and / or a methacrylic acid single polymer, the weight of a hydroxyl group and a carboxyl group can be calculated | required from the weight previously, and this total amount can be calculated | required.

  When the second resin is a resin component having a hydroxyl group and a second functional group, and the second functional group is a carboxyl group, the second coating liquid is used from the viewpoint of the water resistance of the resulting multilayer structure. Preferably contains an alkali metal ion. Examples of alkali metal ions include sodium ions, lithium ions, and potassium ions. The weight of the alkali metal ions contained in the second coating solution is 0.2 to 5 parts with respect to 100 parts by weight of the resin when the weight of the resin contained in the second layer is 100 parts. Is preferable, and more preferably 0.2 to 2 parts.

The alkali metal ion is usually derived from an alkali metal ion donating compound. That is, when the second resin is a resin component having a hydroxyl group and a second functional group, and the second functional group is a carboxyl group, the second coating liquid preferably contains an alkali metal ion donating compound. . Examples of the alkali metal ion donating compound include sodium hydroxide, sodium hypophosphite, lithium hydroxide, potassium hydroxide and the like. When the second inorganic layered compound is montmorillonite, sodium ions are contained between the montmorillonite layers, so that montmorillonite acts as an alkali metal ion donating compound. Therefore, the second inorganic layered compound is particularly preferably montmorillonite. Two or more alkali metal ion donor compounds may be used in combination.

  The second resin contained in the second coating solution is a hydroxyl group, amino group, thiol group, carboxyl group, sulfonic acid group, carboxylate group, sulfonate ion group, phosphate ion group, ammonium group, phosphonium group, or the like. When the resin has a crosslinkable reactive group, a crosslinking agent may be added to the second coating solution. Examples of crosslinking agents used include titanium coupling agents, silane coupling agents, melamine coupling agents, epoxy coupling agents, isocyanate coupling agents, carbodiimide coupling agents, copper compounds, and zirconium compounds. Can be mentioned. Only one kind of these crosslinking agents may be used, or two or more kinds may be appropriately mixed and used.

When the crosslinking agent is added to the second coating liquid, a crosslinking agent solution prepared by dissolving 10 to 90% by weight of a crosslinking agent in a solvent such as alcohol in advance is usually added to the second inorganic layered compound and the second coating liquid. It adjusts by the method of adding to the coating liquid containing resin.
When using a chelate compound for the crosslinking agent, the coating solution is preferably acidic from the viewpoint of the stability of the second coating solution after mixing the crosslinking agent.

  As the second liquid medium, an aqueous medium similar to the first aqueous medium described above can be used. The first aqueous medium and the second aqueous medium may be the same or different. The second liquid medium includes 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-pentane, and n-hexane. , Aliphatic hydrocarbons such as n-octane, halogenated hydrocarbons such as chlorobenzene, carbon tetrachloride, chloroform, dichloromethane, 1,2-dichloroethane, perchloroethylene, ethyl acetate, methyl methacrylate, dioctyl phthalate, It may be an organic liquid medium such as dimethylformamide, dimethyl sulfoxide, methyl cellosolve, or silicone oil.

  It is preferable to add a surfactant to the second coating liquid as well as the first coating liquid.

When adjusting the first coating liquid or the second coating liquid, it is preferable to perform high-pressure dispersion treatment using a high-pressure dispersion apparatus from the viewpoint of dispersibility of the inorganic layered compound. Examples of the high-pressure dispersion device include an ultra-high pressure homogenizer (trade name: Microfluidizer) manufactured by Microfluidics Corporation, a nanomizer manufactured by Nanomizer, a Manton Gorin type high-pressure dispersion device, and a homogenizer manufactured by Izumi Food Machinery. High-pressure dispersion treatment means that high-shearing is applied to the coating liquid by causing the coating liquid to pass through a plurality of thin tubes at a high speed and then causing the coating liquids to collide with each other or between the coating liquid and the inner wall of the thin tubes. And / or a processing method of applying high pressure. In the high-pressure dispersion treatment, it is preferable that the coating liquid is passed through a narrow tube having a tube diameter of about 1 μm to 1000 μm, and at this time, treatment is performed so that a maximum pressure of 100 kgf / cm ² or more is applied. Maximum pressure is more preferably at 500 kgf / cm ² or more, and particularly preferably 1000 kgf / cm ² or more. Further, when the coating solution passes through the narrow tube, the maximum arrival speed of the coating solution is preferably 100 m / s or more, and the heat transfer rate due to pressure loss is preferably 100 kcal / hr or more.

  Next, the base material layer used in the present invention will be described.

  The material which comprises the base material layer used by this invention is not specifically limited, A metal, resin, wood, ceramic, glass, etc. are mentioned. The form of the base material layer is not particularly limited, and examples thereof include paper, cloth, nonwoven fabric, and film. As the resin, a thermoplastic resin or a thermosetting resin can be used. When using the multilayer structure obtained by this invention as a packaging material, it is preferable that a base material layer is comprised from a thermoplastic resin. The thermoplastic resin used is low density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer. Polypropylene (PP), ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, polyolefin resin such as ionomer resin, polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, nylon-6 ( Ny-6), nylon-6,6, polyxylenediamine-adipic acid condensation polymer, amide resins such as polymethylmethacrylamide, acrylic resins such as polymethylmethacrylate, polystyrene, styrene-acrylonitrile Copolymers, styrene-acrylonitrile-butadiene copolymers, styrene-acrylonitrile resins such as polyacrylonitrile, hydrophobized cellulose resins such as cellulose triacetate and cellulose diacetate, halogens such as polyvinyl chloride, polyvinylidene chloride, and polyvinylidene fluoride Containing resin, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, hydrogen bonding resin such as cellulose derivative, polycarbonate resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, polyphenylene oxide resin, polymethylene oxide resin, etc. Is given. Examples of the thermosetting resin include known phenol resins, melamine resins, urea resins and the like. When the multilayer structure obtained in the present invention is a film, the base material layer may be any of an unstretched film, a uniaxially stretched film, and a biaxially stretched film. It is preferable that it is a biaxially stretched film which consists of either. 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 deposited.

  The base material layer may be laminated adjacent to the first layer, or may be laminated via another layer such as an adhesive layer. The first layer may be provided on one surface or both surfaces of the base material layer, or may be provided on a part or the entire surface of the base material layer.

  The substrate layer is subjected to surface treatment such as corona treatment, ozone treatment, ion treatment, flame treatment using a gas such as silane, atmospheric pressure or reduced pressure plasma treatment, etc., in order to laminate this with other layers. Also good. An anchor coat layer may be provided on the surface of the base material layer. The anchor coat layer can be formed using a known ethyleneimine-based, two-component curable urethane-based anchor coat agent or the like.

By forming the first layer and the second layer on the base material layer using the first coating liquid and the second coating liquid, the base material layer, the first layer, A multilayer structure having a second layer adjacent to the first layer is produced. Specifically, it is a method for producing a multilayer structure including the following steps (1) and (2) in order.
(1) A first coating liquid containing a first inorganic layered compound, a first metal alkoxide, and a first aqueous medium is applied onto a base material layer to form a first coating film, and then Removing the first aqueous medium from the first coating film to form a first layer (2) a second containing a second inorganic layered compound, a second resin and a second liquid medium The coating liquid is applied onto the first layer to form a second coating film, and then the second liquid medium is removed from the second coating film to obtain the second layer. Forming on the first layer

A first coating liquid in which a first inorganic layered compound, a first metal alkoxide, and a first aqueous medium are mixed is applied onto the base material layer, and then the first aqueous medium is removed. Thus, the first layer can be formed. When the first layer has a volume of the first layer of 100%, the ratio of the metal oxide when the metal alkoxide-derived metal is all regarded as a metal oxide and converted is 5 to 95 vol%. It is preferable that it is 5-60 vol%, and it is further more preferable that it is 5-30 vol%. Similarly, when the volume of the first layer is 100%, the proportion of the first inorganic layered compound is preferably 5 to 95 vol%, more preferably 40 to 95 vol%, and 70 to 95 vol. % Is more preferable. Usually, the first layer is formed by completely removing the first liquid medium. Therefore, when all the 1st metal alkoxide mix | blended with a 1st coating liquid is converted into a metal oxide, the volume of a 1st inorganic layered compound, and also when this 1st coating liquid contains resin, The ratio in terms of metal oxide when the total volume of the resin is 100% can be regarded as the ratio of metal oxide contained in the first layer.
That is, when the total volume of the first metal alkoxide, the first inorganic layered compound and the resin contained in the first coating liquid is 100%, the ratio of the first metal alkoxide in terms of metal oxide is 5 to 5. What is necessary is just to form a 1st layer using the coating liquid which is 95 vol%.
Similarly, the volume in which all metal alkoxides blended in the first coating liquid are converted into metal oxides, the volume of the first inorganic layered compound, and, if the first coating liquid contains a resin, the resin The ratio of the first inorganic layered compound when the sum of the volume and the total volume is 100% can be regarded as the ratio of the first inorganic layered compound contained in the first layer. That is, for the first inorganic layered compound, when the total volume of the first metal alkoxide, the first inorganic layered compound and the resin contained in the first coating liquid is 100%, What is necessary is just to set it as the coating liquid whose ratio is 5-95 vol%. When the surfactant or the crosslinking agent is contained in the first coating liquid, since these are usually a small amount, the volume of the first layer is the metal oxide equivalent value of the metal alkoxide, the first inorganic layered compound. And the total volume of the resin. By adjusting the ratio of the first metal alkoxide, the first inorganic layered compound and the resin in the first coating liquid to be used, the first inorganic layered compound and the first metal contained in the first layer The proportion of alkoxide can be controlled.

  A second coating liquid containing a second liquid medium, a second inorganic layered compound, and a second resin is applied onto the first layer, and the second liquid medium is removed to remove the second liquid medium. Can be formed. When the second layer has a volume of the second layer of 100%, the ratio of the second inorganic layered compound is preferably 5 to 50 vol%, more preferably 10 to 50 vol%, more preferably It is 15-50 vol%, Most preferably, it is 20-50 vol%. Usually, the second layer is formed by completely removing the second liquid medium. Therefore, the ratio of the second inorganic layered compound when the total volume of the second inorganic layered compound and the second resin in the second coating liquid is 100% is included in the second layer. It can be regarded as a ratio of two inorganic layered compounds. That is, when the total volume of the second inorganic layered compound and the second resin contained in the second coating liquid is 100%, the coating ratio is such that the ratio of the second inorganic layered compound is 5 to 50 vol%. It is preferable to form the second layer using a working liquid. When the coating liquid contains a surfactant or a crosslinking agent, since these are usually a small amount, the volume of the second layer is regarded as the total volume of the second inorganic layered compound and the second resin. By adjusting the ratio of the second inorganic layered compound in the second coating liquid to be used, the ratio of the second inorganic layered compound contained in the second layer can be controlled.

  The first coating solution, the second coating solution, and the method for applying the anchor coating agent include gravure methods such as direct gravure method and reverse gravure method, two roll beat coating method, bottom feed three reverse coating method. Roll coating method such as doctor coating method, die coating method, bar coating method, dipping method, spray coating method. Further, the additional layer and the resin layer described above can be provided by the same method. When the base material layer is a film, it is preferable to employ a gravure method because a layer having a uniform thickness can be provided.

  The thickness of each layer which comprises the multilayer structure obtained by this invention is not specifically limited. The thicknesses of the first layer and the second layer are usually 1 nm to 10 μm, preferably 1 nm to 1 μm, and more preferably 1 nm to 500 nm from the viewpoint of gas barrier properties and cost. The multilayer structure obtained by the present invention has sufficient gas barrier properties even when the first layer and the second layer are thin as described above. From the viewpoint of bending resistance, the thickness of the first layer is preferably equal to the thickness of the second layer or thinner than the second layer. The thickness of the additional layer and the resin layer 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 obtained in the present invention may contain various additives such as an ultraviolet absorber, a colorant, an antioxidant, and the like as long as the effects of the present invention are not impaired. .

  In the multilayer structure obtained by the present invention, the first layer and the second layer are laminated adjacent to each other, and the first layer is disposed between the base material layer and the second layer. It is the composition which becomes. A multilayer structure obtained by the present invention having a configuration such as base material layer / first layer / second layer, and a multilayer structure having a configuration as base material layer / second layer / first layer; Should theoretically exhibit the same gas barrier properties. However, in reality, it has been found that a multilayer structure having excellent gas barrier properties can be obtained by adopting the configuration of the present invention.

The multilayer structure obtained in the present invention may have a layer other than the first layer, the second layer, and the base material layer, and each of the layers having the same composition as the first layer and the second layer. You may have multiple layers. As a structure of the multilayer structure obtained by the present invention, for example, base material layer / first layer / second layer (structure 1),
Base layer / first layer / second layer / additional layer A (Configuration 2),
Base layer / first layer / second layer / additional layer B / additional layer C (Configuration 3),
Base layer / first layer / second layer / additional layer D / additional layer E / additional layer F (configuration 4),
Base material layer / first layer / second layer / resin layer (Configuration 5),
Base layer / first layer / second layer / additional layer B / additional layer C / resin layer (configuration 6),
Base material layer / first layer / second layer / addition layer D / addition layer E / addition layer F / resin layer (Configuration 7)
Base material layer / additional layer G / first layer / second layer (configuration 8)
Base layer / additional layer G / first layer / second layer / additional layer A (Configuration 9),
Base layer / additional layer G / first layer / second layer / additional layer B / additional layer C (configuration 10),
Base layer / additional layer G / first layer / second layer / additional layer D / additional layer E / additional layer F (configuration 11),
Base layer / additional layer G / first layer / second layer / resin layer (Configuration 12),
Base layer / additional layer G / first layer / second layer / additional layer B / additional layer C / resin layer (Configuration 13),
Base layer / addition layer G / first layer / second layer / addition layer D / addition layer E / addition layer F / resin layer (Configuration 14)
Is mentioned.
Here, the additional layers A, B, C, D, E, F, and G may have the same composition as the first layer or the second layer, respectively. For example, in the configuration 2 or the configuration 9, the additional layer A may have the same composition as the first layer. In the configuration 3, the configuration 6, the configuration 10 or the configuration 13, the additional layer B is the first layer and the additional layer C It may be the same composition as the second layer. Further, in the configuration 4, the configuration 7, the configuration 11 or the configuration 14, the additional layers D and F may have the same composition as the first layer, and the additional layer E may have the same composition as the second layer. Similarly, the additional layer G in the structures 8 to 14 may have the same composition as the second layer.

  The multilayer structure obtained by the present invention is preferably heat-treated in advance at 100 ° C. or more and 300 ° C. or less before use from the viewpoint of improving gas barrier properties. The heat source used for the heat treatment is not particularly limited, and various methods such as hot 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.

  Further, in the multilayer structure obtained by the present invention, when the resin contained in the first layer and / or the second layer is a resin containing a hydroxyl group and a carboxyl group, a wet heat treatment is performed after the heat treatment, followed by drying. It is preferable to process. The wet heat treatment is a treatment for aging under conditions of a humidity of 90% RH or more and a temperature of 100 ° C. or more. Specific treatment methods for the wet heat treatment include a method of aging in a steam atmosphere and a method of immersing the multilayer structure in hot water. The time for the wet heat treatment is usually 1 second to 1 hour. The drying treatment after the wet heat treatment is a treatment for removing moisture given to the multilayer structure by the wet heat treatment. Usually, it may be aged at a humidity of 50% RH or less and a temperature of 20 to 100 ° C. for 1 second to 24 hours. Prior to wet heat treatment, the heat treated multilayer structure may be aged, for example, at 23 ° C. and 50% RH.

Examples of the multilayer structure obtained by the present invention include tires and screws, optical component members such as flexible display substrates or sealing materials for liquid crystal displays, organic EL, substrates such as solar cells or dye-sensitized solar cells, sealing Examples thereof include electronic component members such as materials. 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. Thus, by stacking the first layer and the second layer on various conventional products that do not have the first layer and the second layer, a multilayer structure obtained in the present invention can be obtained. It is possible to suppress oxygen deterioration of a product that has been deteriorated due to the above. It can also be used as a vacuum insulation panel.
Further, by using the multilayer structure obtained in 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 obtained in the present invention is used as a packaging material, examples of its shape include a film, a bag, a pouch, a bottle, a bottle cap, a carton container, a cup, a dish, a tray, a tank, and a tube. The multilayer structure obtained by the present invention is particularly preferably used as a packaging material for retort because it has excellent post-retort barrier properties. The contents packaged by the multilayer structure obtained in the present invention include cakes, pastries such as castella, Japanese confectionery such as Daifuku and mochi, confectionery such as snack confectionery such as potato chips, marine products such as bamboo rings and rice cakes, Examples include foods such as miso, pickles, rice cakes, meatballs, hamburger, ham and sausage, beverages such as coffee, tea and juice, dairy products such as milk and yogurt, cooked rice and curry. In addition to food products, toiletries such as detergents, baths, and cosmetics, fuels such as gasoline and hydrogen gas, pharmaceuticals and medical devices such as powders, tablets, eye drops, and infusion bags, electronic components such as hard disks and silicon wafers, It can also be used as a packaging material for electronic devices.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. Measurement methods for 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 thickness gauge, trade name: ultra-high precision deci-micro head MH-15M, manufactured by Nippon Optical Co., Ltd.) The thickness of less than 0.5 μm was determined by cross-sectional observation with a transmission electron microscope (TEM).

(Particle size measurement)
Measurement was performed using a laser diffraction / scattering particle size distribution analyzer (LA910, manufactured by Horiba, Ltd.). The coating liquids (1) to (5) are diluted, the average particle size of the inorganic layered compound in the diluted solution is measured with an optical path length of 4 mm in a flow cell, and the obtained average particle size is the average of the inorganic layered compound The particle size L was considered.
In addition, without diluting coating liquid (1)-(5), the average particle diameter of the inorganic layered compound in this coating liquid was measured by optical path length 50micrometer with a paste cell, and this average particle diameter and dilution When the value of the average particle diameter L obtained with the liquid almost coincided, it was determined that the inorganic layered compound was sufficiently swollen and cleaved in the coating liquid.

[Aspect ratio calculation]
Using an X-ray diffractometer (XD-5A, manufactured by Shimadzu Corporation), the inorganic layered compound itself was subjected to diffraction measurement by a powder method. As a result, the unit thickness a of the inorganic stratiform compound was determined, and the aspect ratio Z was calculated from the equation Z = L / a using the particle size L determined by the above-described method. In addition, about what dried coating liquid (1)-(5), the X-ray-diffraction measurement was also performed and it confirmed that the surface interval of the inorganic layered compound was spreading.

〔Heat treatment〕
A 210 mm × 300 mm multilayer structure was heat-treated in an oven at 150 ° C. and 2% RH for 60 minutes.

[Drying treatment]
The 210 mm × 300 mm multilayer structure after the wet heat treatment was allowed to stand for 24 hours in an atmosphere of 23 ° C. and 50% RH.

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

[Preparation of coating solution]
Preparation of Coating Liquid (1) A dispersion kettle (trade name: Despa MH-L, manufactured by Asada Tekko Co., Ltd.), 1300 g of ion-exchanged water (specific electric conductivity 0.7 μs / cm or less) and polyvinyl alcohol (AQ2117) Manufactured by Kuraray Co., Ltd., saponification degree: 99.6%, polymerization degree 1,700) and 130 g were mixed and heated 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 the 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 obtained 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 completion of the dropping, switching to high-speed stirring (3,000 rpm, peripheral speed = 8.2 m / min), 65 g of high-purity montmorillonite (trade name: Kunipia G; manufactured by Kunimine Industry Co., Ltd.) was gradually added to the stirring system, After completion of the addition, stirring was continued at 60 ° C. for 60 minutes. Thereafter, 243 g of isopropanol was further added over 15 minutes, and then the mixed system was cooled to room temperature. Further, a nonionic surfactant (polydimethylsiloxane-polyoxyethylene copolymer, trade name: SH3746, Toray Dow Corning) 0.1 wt% (based on the weight of the containing liquid) was added to obtain an inorganic layered compound dispersion (A). Further, this inorganic layered compound dispersion (A) was treated under the condition of 1100 kgf / cm ² using a high-pressure dispersion device (trade name: Super High Pressure Homogenizer M110-E / H, manufactured by Microfluidics Corporation) to obtain an inorganic layered compound dispersion. (B) was obtained. The cleaved montmorillonite average particle diameter in the inorganic layered compound dispersion (B) was 560 nm, the a value obtained from powder X-ray diffraction was 1.2156 nm, and the aspect ratio was 460. The pH of the inorganic layered compound dispersion (B) was 8.
By slowly adding the inorganic layered compound dispersion (B) while adjusting with sodium hydroxide so that the pH of the system becomes 8 under low speed stirring (1500 rpm, peripheral speed 4.1 m / min). A coating liquid (1) was prepared. When the total volume of the polyvinyl alcohol and the inorganic layered compound in the coating liquid (1) was 100%, the proportion of the inorganic layered compound was 20 vol%.

Preparation of coating liquid (2) High-purity montmorillonite was added to the stirring system under high-speed stirring (3,000 rpm, peripheral speed = 8.2 m / min) with 1000 g of ion-exchanged water and 1000 g of isopropanol at room temperature using a stirrer. (Product name: Kunipia G; manufactured by Kunimine Kogyo Co., Ltd.) was gradually added. After the addition was completed, stirring was continued for 60 minutes at room temperature. Thereafter, hydrochloric acid was added and adjusted so that the pH of the system was 3 or less to prepare an inorganic layered compound dispersion (C). Thereafter, the temperature was raised to 80 ° C. under low speed stirring (1500 rpm, peripheral speed 4.1 m / min), and 2.4 g of tetraethoxysilane (manufactured by Wako Pure Chemical Industries, Ltd.) was added to the inorganic layered compound dispersion (C). Was gradually added, stirred at the same temperature for 60 minutes, and then returned to room temperature to prepare a coating liquid (2). In the coating liquid (2), when the total volume of the inorganic layered compound used and the volume of SiO ₂ when tetraethoxysilane is converted to SiO ₂ is 100 vol%, the ratio of the inorganic layer compound is 95 vol%. and is a coating liquid ratio of SiO ₂ in the case of converting the tetraethoxysilane SiO ₂ is 5 vol%.

Preparation of coating liquid (3) A coating liquid (3) was prepared in the same manner as the coating liquid (2) except that 1.4 g of high-purity montmorillonite and 6.5 g of tetraethoxysilane were used. In the coating liquid (3), when the total volume of the volume of the inorganic layered compound used and the volume of SiO ₂ when tetraethoxysilane is converted to SiO ₂ is 100 vol%, the proportion of the inorganic layer compound is 41 vol%. and is a coating liquid ratio of SiO ₂ in the case of converting the tetraethoxysilane SiO ₂ is 59vol%.

Preparation of coating liquid (4) A coating liquid (4 ') was prepared in the same manner as the coating liquid (1) except that 102 g of high-purity montmorillonite was used. Thereafter, the temperature was raised to 80 ° C. under low speed stirring (1500 rpm, peripheral speed 4.1 m / min), and 12.6 g of tetraethoxysilane (manufactured by Wako Pure Chemical Industries, Ltd.) was gradually added to the coating solution (4 ′). In addition, the mixture was stirred at the same temperature for 60 minutes and then returned to room temperature to prepare a coating liquid (4). Coating liquid (4) is a coating liquid volume ratio of SiO ₂ is 71/28/1 in the case of converting the resin and the inorganic layered compound and tetraethoxysilane used for SiO _2.

Preparation of coating liquid (5) A coating liquid (5 ') was prepared in the same manner as the coating liquid (1) except that 80 g of high-purity montmorillonite was used. Thereafter, the temperature was raised to 80 ° C. under low speed stirring (1500 rpm, peripheral speed 4.1 m / min), and 88 g of tetraethoxysilane (manufactured by Wako Pure Chemical Industries, Ltd.) was gradually added to the coating solution (5 ′). After stirring for 60 minutes at the same temperature, the temperature was returned to room temperature to prepare a coating liquid (4). Coating liquid (4) is a coating liquid volume ratio of SiO ₂ is 71/22/7 in the case of converting the resin and the inorganic layered compound and tetraethoxysilane used for SiO _2.

[Example 1]
A biaxially stretched polyethylene terephthalate (PET) film (trade name: PTM; manufactured by Unitika Co., Ltd.) having a thickness of 12 μm is subjected to corona treatment to form a base material layer. The coating liquid (1) is subjected to gravure coating at a coating speed of 3 m / min using a test coater (manufactured by Yasui Seiki Co., Ltd.) with a micro gravure coating method (number of gravure rolls: 300) and dried at a drying temperature of 100 ° C. And an undercoat layer was formed. The thickness of the undercoat layer was 0.04 μm. Let this undercoat layer be A1 layer. Next, the coating liquid (2) was applied onto the A1 layer in the same manner as the coating liquid (1) and dried to form a first layer. The first layer is referred to as a B1 layer. Further, the coating liquid (1) was applied onto the B1 layer by the same method as described above and dried to form a second layer. The second layer is referred to as an A2 layer. Thus, the multilayer structure of 4 layers (base material layer / A1 layer / B1 layer / A2 layer) including the base material layer was obtained. The total thickness of the coating layer after drying in the multilayer structure, that is, the thickness of the A1 layer / B1 layer / A2 layer was 0.09 μm. Since the thickness of the A1 layer was 0.04 μm, the thickness of the A2 layer is also 0.04 μm, and the thickness of the B1 layer is calculated to be 0.01 μm.
In addition, the ratio of the inorganic layered compound contained in each layer of A1 layer and A2 layer is the ratio of the inorganic layered compound when the total volume of the polyvinyl alcohol and the inorganic layered compound in the used coating liquid (1) is 100%. It can be regarded as equal and is 20 vol%.
The ratio of SiO ₂ in the case of converting the rate and tetraethoxysilane of the inorganic layered compound contained in the layer B1 to SiO ₂ is, SiO volume and tetraethoxysilane inorganic layered compound in the coating liquid (2) using the total volume of the SiO ₂ volume when converted to ₂ can be regarded as equal to the proportion of SiO ₂ in the case where the rate and tetraethoxysilane inorganic layered compounds is taken as 100% in terms of SiO _2, respectively 95 vol% and 5 vol%. Further, when the total volume of all the coating layers (that is, the A1 layer, the B1 layer, and the A2 layer) (referred to as “all coating layers”) is 100%, the resin contained in the all coating layers, the inorganic layer shape compound and volume ratio of SiO ₂ in the case of converting the tetraethoxysilane SiO ₂ becomes 71/28/1.
The obtained multilayer structure was heat-treated, then dried, and then measured for oxygen permeability. 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 coating liquid (3) was used instead of the coating liquid (2). The structure of the obtained multilayer structure is base material layer / A1 layer / C1 layer / A2 layer, and the total thickness of the coating layer after drying in the multilayer structure, that is, A1 layer / C1 layer / A2 layer The thickness was 0.09 μm. Since the thickness of the A1 layer was 0.04 μm, the thickness of the A2 layer is also 0.04 μm, and the thickness of the B1 layer is calculated to be 0.01 μm.
In addition, the ratio of the inorganic layered compound contained in each layer of A1 layer and A2 layer is the ratio of the inorganic layered compound when the total volume of the polyvinyl alcohol and the inorganic layered compound in the used coating liquid (1) is 100%. It can be regarded as equal and is 20 vol%.
The ratio of the inorganic layered compound contained in the B1 layer and the ratio when tetraethoxysilane is converted to SiO ₂ are the volume of the inorganic layered compound in the coating liquid (3) used and tetraethoxysilane converted to SiO ₂ . the total volume of SiO ₂ in the volume when the can be considered equal to the ratio of SiO ₂ in the case of converting the rate and tetraethoxysilane inorganic layered compounds is 100 percent SiO _2, respectively 41Vol% 59 vol%. Further, when the total volume of all the coating layers (namely, the A1 layer, the C1 layer, and the A2 layer) (referred to as “all coating layers”) is 100%, the resin and inorganic layered compound contained in the all coating layers The volume ratio of SiO ₂ when tetraethoxysilane is converted to SiO ₂ is 71/22/7.
The obtained multilayer structure was heat-treated, then dried, and then measured for oxygen permeability. The results are shown in Table 2.

[Comparative Example 1]
A multilayer structure was obtained in the same manner as in Example 1 except that the coating liquid (4) was used instead of the coating liquid (1) and the coating liquid (2). The structure of the obtained multilayer structure was base material layer / D1 layer, and the total thickness of the coating layer after drying in the multilayer structure, that is, the thickness of the D1 layer was 0.12 μm.
The volume ratio of SiO ₂ when the resin, inorganic layer compound, and tetraethoxysilane contained in the D1 layer are converted to SiO ₂ is the same as that of the resin, inorganic layer compound, and tetraethoxysilane in the coating liquid (4) used. It can be regarded as equal to the SiO ₂ in the volume ratio when converted to SiO _2, a 71/28/1.
The obtained multilayer structure was heat-treated, then dried, and then measured for oxygen permeability. 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 coating liquid (5) was used instead of the coating liquid (1) and the coating liquid (2). The structure of the obtained multilayer structure was substrate layer / E1 layer, and the total thickness of the coating layer after drying in the multilayer structure, that is, the thickness of the E1 layer was 0.12 μm.
The volume ratio of SiO ₂ when the resin, inorganic layer compound and tetraethoxysilane contained in the E1 layer are converted to SiO ₂ is the same as that of the resin, inorganic layer compound and tetraethoxysilane used in the coating liquid (5). It can be regarded as being equal to the volume ratio of SiO ₂ when converted to SiO _2, which is 71/22/7.
The obtained multilayer structure was heat-treated, then dried, and then measured for oxygen permeability. The results are shown in Table 2.

[Comparative Example 3]
The coating liquid (1) was used instead of the coating liquid (2) for forming the first layer, and the coating liquid (2) was used instead of the coating liquid (1) for forming the second layer. A multilayer structure was obtained in the same manner as in Example 1 except for the above. The structure of the obtained multilayer structure is substrate layer / A1 layer / A2 layer / B1 layer, and the total thickness of the coating layer after drying in the multilayer structure, that is, A1 layer / A2 layer / B1 layer The thickness was 0.09 μm. Since the thickness of the A1 layer was 0.04 μm, the thickness of the A2 layer is also 0.04 μm, and the thickness of the B1 layer is calculated to be 0.01 μm.
In addition, the ratio of the inorganic layered compound contained in each layer of A1 layer and A2 layer is the ratio of the inorganic layered compound when the total volume of the polyvinyl alcohol and the inorganic layered compound in the used coating liquid (1) is 100%. It can be regarded as equal and is 20 vol%.
The ratio of SiO ₂ in the case of converting the rate and tetraethoxysilane of the inorganic layered compound contained in the layer B1 to SiO ₂ is, SiO volume and tetraethoxysilane inorganic layered compound in the coating liquid (2) using the total volume of the SiO ₂ volume when converted to ₂ can be regarded as equal to the proportion of SiO ₂ in the case where the rate and tetraethoxysilane inorganic layered compounds is taken as 100% in terms of SiO _2, respectively 95 vol% and 5 vol%. Further, when the total volume of all the coating layers (namely, the A1 layer, the A2 layer and the B1 layer) (referred to as “all coating layers”) is 100%, the resin and inorganic layer form contained in the all coating layers compound and volume ratio of SiO ₂ in the case of converting the tetraethoxysilane SiO ₂ becomes 71/28/1.
The obtained multilayer structure was heat-treated, then dried, and then measured for oxygen permeability. The results are shown in Table 1.

[Comparative Example 4]
The coating liquid (1) was used instead of the coating liquid (2) forming the first layer, and the coating liquid (3) was used instead of the coating liquid (1) forming the second layer. A multilayer structure was obtained in the same manner as in Example 1 except for the above. The structure of the obtained multilayer structure is substrate layer / A1 layer / A2 layer / C1 layer, and the total thickness of the coating layer after drying in the multilayer structure, that is, A1 layer / A2 layer / C1 layer The thickness was 0.09 μm. Since the thickness of the A1 layer was 0.04 μm, the thickness of the A2 layer is similarly 0.04 μm, and the thickness of the C1 layer is calculated to be 0.01 μm.
In addition, the ratio of the inorganic layered compound contained in each layer of A1 layer and A2 layer is the ratio of the inorganic layered compound when the total volume of the polyvinyl alcohol and the inorganic layered compound in the used coating liquid (1) is 100%. It can be regarded as equal and is 20 vol%.
Ratio and the proportion of SiO ₂ in the case of tetraethoxysilane was converted to SiO ₂ of The inorganic layered compound contained in the C1 layer, SiO volume and tetraethoxysilane inorganic layered compound in the coating liquid (3) using It can be considered that the ratio of the inorganic layered compound when the total volume of the volume when converted to ₂ is 100% and the ratio of SiO ₂ when tetraethoxysilane is converted to SiO ₂ are 41 vol%, respectively. 59 vol%. Further, when the total volume of all the coating layers (namely, the A1 layer, the A2 layer and the B1 layer) (referred to as “all coating layers”) is 100%, the resin and inorganic layer form contained in the all coating layers The volume ratio of SiO ₂ when the compound and tetraethoxysilane are converted to SiO ₂ is 71/22/7.
The obtained multilayer structure was heat-treated, then dried, and then measured for oxygen permeability. The results are shown in Table 2.

Claims (5)

A method for producing a multilayer structure having a base material layer, a first layer, and a second layer adjacent on the first layer,
The ratio of the first inorganic layered compound contained in the first layer is 40 to 95 vol% (however, the volume of the first layer is 100%),
The manufacturing method of the multilayer structure which contains the following processes (1) and (2) in order.
(1) A first coating liquid containing a first inorganic layered compound, a first metal alkoxide, and a first aqueous medium is applied onto a base material layer to form a first coating film, and then Removing the first aqueous medium from the first coating film to form a first layer (2) a second containing a second inorganic layered compound, a second resin and a second liquid medium The coating liquid is applied onto the first layer to form a second coating film, and then the second liquid medium is removed from the second coating film to obtain the second layer. Forming on the first layer   When all the metals derived from the first metal alkoxide are converted into metal oxides, the ratio of the metal oxides contained in the first layer is 5 to 95 vol% (however, the volume of the first layer is 100%) The method for producing a multilayer structure according to claim 1.   The ratio of the 2nd inorganic layered compound contained in the said 2nd layer is 5-50 vol% (however, the volume of a 2nd layer shall be 100%). The manufacture of the multilayer structure of Claim 1 or 2 Method.   The method for producing a multilayer structure according to any one of claims 1 to 3, wherein the metal of the first metal alkoxide is Si and / or Al.   The method for producing a multilayer structure according to claim 1, wherein the second resin is a resin having a hydroxyl group.