JP4812382B2 - Gas barrier laminated film - Google Patents

Description

  The present invention relates to a laminated film excellent in gas barrier properties that can be suitably used as various packaging materials.

Conventionally, a gas barrier plastic film that uses a plastic film as a base material and an inorganic thin film such as silicon oxide, aluminum oxide, or magnesium oxide is formed on the surface of the plastic film. Packaging for articles that require blocking of various gases such as water vapor and oxygen. For example, it is widely used for packaging for preventing deterioration of food, industrial products, pharmaceuticals, and the like. In addition to packaging applications, this gas barrier plastic film has recently attracted attention for new applications as a transparent conductive sheet used in liquid crystal display elements, solar cells, electromagnetic wave shields, touch panels, EL substrates, color filters, etc. Has been.
With regard to the gas barrier plastic film formed with such an inorganic thin film, various improvements have been studied for the purpose of improving gas barrier properties and moisture proofing, for example, at least one surface of a polymer film substrate. And a mixture containing polyvinyl alcohol and polycarboxylic acid or a partially neutralized product thereof in a ratio of 95: 5 to 10:90 (mass ratio). A composite film containing at least one laminated structure in which a water-resistant film formed from is laminated, wherein a layer of a polymer composition containing a desiccant is disposed on at least one side of the laminated structure The moisture-proof composite film (see Patent Document 1) has a surface on which the vapor-deposited layer of ceramic is coated with polyvinyl alcohol and ethylene / unsaturated carboxylic acid. Method of coating an aqueous dispersion of polymer (see Patent Document 2) are disclosed.

  However, although the moisture resistance and the like are improved to some extent in the above film, the gas barrier property and the adhesion strength between the constituent layers of the laminate are still insufficient, and the improvement has been desired.

JP-A-8-142255 JP 2003-49035 A

  The problem to be solved by the present invention is to provide a laminated film exhibiting high gas barrier properties and excellent adhesion strength between constituent layers.

  The above-mentioned problem of the present invention is that a resin layer formed by applying an aqueous liquid containing (a) polyvinyl alcohol and (b) an ethylene / unsaturated carboxylic acid copolymer to at least one surface of a base film, and A gas barrier laminate film having an inorganic thin film formed on the resin layer is solved.

  ADVANTAGE OF THE INVENTION According to this invention, the gas barrier property laminated | multilayer film which shows high gas barrier property and was excellent in the adhesive strength between structural layers can be provided.

Hereinafter, the present invention will be described in detail.
The base film of the gas barrier laminate film of the present invention is preferably a thermoplastic polymer film, and the raw material thereof can be used without particular limitation as long as it is a resin that can be used for ordinary packaging materials. Specifically, polyolefins such as homopolymers or copolymers such as ethylene, propylene and butene, amorphous polyolefins such as cyclic polyolefin, polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, nylon 6, nylon 66, polyamide such as nylon 12, copolymer nylon, ethylene-vinyl acetate copolymer partial hydrolyzate (EVOH), polyimide, polyetherimide, polysulfone, polyethersulfone, polyetheretherketone, polycarbonate, polyvinyl butyral, Examples include polyarylate, fluororesin, acrylate resin, and biodegradable resin. Among these, polyester, polyamide, polyolefin, and biodegradable resin are preferable from the viewpoint of film strength and cost.
The base film is a known additive such as an antistatic agent, a light blocking agent, an ultraviolet absorber, a plasticizer, a lubricant, a filler, a colorant, a stabilizer, a lubricant, a crosslinking agent, an antiblocking agent, An antioxidant etc. can be contained.

The thermoplastic polymer film as the substrate film is formed by using the above raw materials, but when used as a substrate, it may be unstretched or stretched. Good. Moreover, you may laminate | stack with the other plastic base material. Such a base film can be produced by a conventionally known method. For example, the raw material resin is melted by an extruder, extruded by an annular die or a T-die, and rapidly cooled to be oriented substantially amorphously. No unstretched film can be produced. The unstretched film is subjected to a known method such as uniaxial stretching, tenter sequential biaxial stretching, tenter simultaneous biaxial stretching, tubular simultaneous biaxial stretching, or the like. A film stretched in at least a uniaxial direction can be produced by stretching in a direction (horizontal axis) perpendicular thereto. As the base film, a film obtained by coating the base film in a film manufacturing process (so-called in-line coating method) may be used.
The thickness of the base film is usually 5 to 500 μm, preferably 10 to 200 μm, depending on its use from the viewpoint of mechanical strength, flexibility, transparency, etc. as the base material of the gas barrier laminate film of the present invention. A sheet-like material selected in a range and having a large thickness is also included. Moreover, there is no restriction | limiting in particular about the width | variety and length of a film, According to a use, it can select suitably.

  In the present invention, at least one surface of the substrate film contains (a) polyvinyl alcohol and (b) an ethylene / unsaturated carboxylic acid copolymer in order to improve adhesion to the inorganic thin film. A resin layer formed by applying an aqueous liquid (hereinafter sometimes referred to as “the aqueous liquid of the present invention”) is provided. The aqueous liquid of the present invention constituting the resin layer will be described below.

(A) Polyvinyl alcohol Polyvinyl alcohol can be obtained by a known method, and can usually be obtained by saponifying a polymer of vinyl acetate. A saponification degree of 80% or more can be used, preferably 90% or more, more preferably 95% or more, and particularly preferably 98% or more from the viewpoint of gas barrier properties.
The average degree of polymerization is usually 500 to 3000, and preferably 500 to 2000 in terms of gas barrier properties and stretchability. Moreover, what copolymerized ethylene in the ratio of 40% or less as polyvinyl alcohol can also be used. The aqueous liquid of polyvinyl alcohol is prepared by, for example, supplying a polyvinyl alcohol resin while stirring in normal temperature water, raising the temperature, and stirring at 80 to 95 ° C. for 30 to 60 minutes.

(B) Ethylene / unsaturated carboxylic acid copolymer Ethylene / unsaturated carboxylic acid copolymer is composed of ethylene, acrylic acid, methacrylic acid, ethacrylic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate, and maleic acid. It is a copolymer with an unsaturated carboxylic acid such as monoethyl, maleic anhydride, itaconic anhydride, etc. Among them, a copolymer of ethylene and acrylic acid or methacrylic acid is preferable from the viewpoint of versatility. The ethylene-unsaturated carboxylic acid copolymer may contain any other monomer.

  The ethylene component in the ethylene / unsaturated carboxylic acid copolymer is preferably 65 to 90% by mass, more preferably 70 to 85% by mass from the viewpoint of versatility and flexibility, and the unsaturated carboxylic acid component is preferably 10%. It is -35 mass%, More preferably, it is 15-30 mass%. The melt flow rate (MFR) at 190 ° C. under a load of 2160 g of the ethylene / unsaturated carboxylic acid copolymer is preferably 30 to 2000 g / 10 minutes, more preferably 60 to 1500 g, from the viewpoint of the bending resistance of the film. / 10 minutes. The number average molecular weight is preferably in the range of 2000 to 250,000.

  Other monomers that may be included in the ethylene / unsaturated carboxylic acid copolymer include vinyl esters such as vinyl acetate and vinyl propionate, methyl acrylate, ethyl acrylate, isopropyl acrylate, and acrylic acid. Examples include n-butyl, isobutyl acrylate, isooctyl acrylate, methyl methacrylate, isobutyl methacrylate, dimethyl maleate, diethyl maleate, and other unsaturated carboxylic acid esters such as carbon monoxide and sulfur dioxide. A monomer can be contained in the ratio of 0-50 mass%. Such an ethylene / unsaturated carboxylic acid copolymer can be obtained by a known method such as radical polymerization under high temperature and high pressure.

In the present invention, from the viewpoint of gas barrier properties, interlayer adhesion, etc., the ethylene / unsaturated carboxylic acid copolymer preferably contains a partially neutralized product, and the degree of neutralization of the partially neutralized product is a gas barrier. From the viewpoint of property, it is preferably 20 to 100%, more preferably 40 to 100%, and particularly preferably 60 to 100%. The degree of neutralization can be obtained from the following formula.
Degree of neutralization = (A / B) x 100 (%)
A: Number of moles of neutralized carboxyl group in 1 g of partially neutralized ethylene / unsaturated carboxylic acid copolymer B: Carboxyl group in 1 g of ethylene / unsaturated carboxylic acid copolymer before partial neutralization In the case of an aqueous liquid, for convenience, the above-mentioned A is defined as (number of metal ions in the solvent) x (valence of the metal ions) and B is partially neutralized with ethylene / unsaturated carboxylic acid. It can be calculated as the number of carboxyl groups in the acid copolymer.

The ethylene / unsaturated carboxylic acid copolymer of the present invention comprises the above copolymer and an aqueous medium containing ammonia, sodium hydroxide, potassium hydroxide, lithium hydroxide and the like from the viewpoint of gas barrier properties and interlayer adhesion. It is preferably used as an aqueous liquid, and the above-mentioned neutralization degree is 20 to 100%, more preferably 40 to 100% with respect to the total number of moles of carboxyl groups of the ethylene / unsaturated carboxylic acid copolymer. What uses the said aqueous medium is used preferably.
In order to produce an aqueous liquid from an ethylene / unsaturated carboxylic acid copolymer and the above aqueous medium, for example, a predetermined amount of water and the above two raw materials are supplied to a stirrable container, and the temperature is 90 to 150 ° C. It can be obtained by stirring for about 2 to 2 hours. The aqueous liquid thus obtained has excellent stability, and the particle size and viscosity do not change significantly even when stored for a long time.

In the present invention, the ethylene / unsaturated carboxylic acid copolymer may further contain a divalent or trivalent metal. Such a divalent or trivalent metal can be dispersed by adding it as an oxide when an aqueous liquid is produced together with an aqueous medium. Further, in addition to the oxide, it can be introduced in the form of a metal carbonate salt or a sulfate metal salt. The compounding quantity can be introduced at a ratio of 0 to 60 mol% with respect to the number of moles of carboxyl groups of the ethylene-unsaturated carboxylic acid copolymer.
In the present invention, the ethylene-unsaturated carboxylic acid copolymer may be used singly or in combination of two or more.

The aqueous liquid of the present invention preferably contains a silica component. Inclusion of the silica component improves cohesive fracture resistance and adhesion, contributing to water resistance.
The silica component that can be used in the present invention is not particularly limited, and any known component can be used. For example, from the viewpoint of interlayer adhesion, gas barrier properties, and the like, A silica component obtained by hydrolytic condensation of alkoxysilane is preferably used.
When the silica component is silica particles, the particle diameter is preferably 1 to 20 nm, more preferably 1 to 10 nm in terms of average particle diameter from the viewpoint of cohesive fracture resistance and film flatness. The particle size of the silica particles can be measured by a method such as nitrogen gas adsorption (BET) method, electron microscope observation method, small angle X-ray scattering analysis method, dynamic light scattering method, etc. The value measured by the dynamic light scattering method is used.
In order to provide interlayer adhesion and surface flatness, high molecular level miscibility with the resin and appropriate cohesiveness are required, and for that purpose, the silica component has a small particle size when in the form of particles, It preferably has a silanol group.

The method for preparing the silica particles is not particularly limited. For example, the international publication pamphlet WO95 / 17349, page 2, line 16 to page 10, line 26, or paragraphs [0012] to [0031] of JP-A-6-16414. Can be prepared by, for example, a method of hydrolyzing and aging alkoxysilane, or a method of dissolving water glass, ion-exchange and concentrating.
In this invention, the said silica component may be used by 1 type, However, 2 or more types can also be used in combination.

In the aqueous liquid of the present invention, the content ratio of the polyvinyl alcohol and the ethylene / unsaturated carboxylic acid copolymer is 95/5 to 5/95 (polyvinyl alcohol / ethylene / unsaturated carboxylic acid copolymer) in terms of the solid mass ratio. Further, it is preferably 80/20 to 50/50, whereby an inorganic thin film exhibiting high adhesion between the base film and the inorganic thin film and exhibiting high gas barrier properties can be obtained.
In the present invention, the silica component is preferably based on the total amount of the component (a), the component (b) and the silica component in the aqueous liquid in terms of easy tearability, interlayer adhesion, and film flatness. 2-80 mass%, More preferably, it contains 2-50 mass%.

Various known additives can be blended in the aqueous liquid of the present invention as necessary. Examples of such additives include polyhydric alcohols such as glycerin, ethylene glycol, polyethylene glycol, and polypropylene glycol, aqueous epoxy resins, silane coupling agents, lower alcohols such as methanol, ethanol, normal propanol, and isopropanol, and ethylene glycol monomethyl ether. , Ethers such as propylene glycol monomethyl ether, propylene glycol diethyl ether, diethylene glycol monoethyl ether, propylene glycol monoethyl ether, esters such as propylene glycol monoacetate and ethylene glycol monoacetate, antioxidants, weathering stabilizers, UV absorption Agents, antistatic agents, pigments, dyes, antibacterial agents, lubricants, inorganic fillers, antiblocking agents, adhesives, etc. It is thing.
Moreover, as a crosslinking component, a resin containing a blocked isocyanate group, an oxazoline group, a carbodiimide group, an epoxy group, or the like, a silane coupling agent, or the like can be appropriately added.

  Furthermore, the aqueous liquid of the present invention can be used by mixing with an aqueous liquid of another polymer. Such polymer aqueous liquids include polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, aqueous acrylic resin, acrylamide resin, methacrylamide resin, acrylonitrile resin, styrene-acrylic acid copolymer. Polymer, aqueous polyurethane resin, aqueous styrene-maleic acid copolymer, styrene-butadiene copolymer, high impact polystyrene resin, butadiene resin, polyester resin, acrylonitrile-butadiene copolymer, polyethylene resin, polyethylene oxide resin, propylene-ethylene Copolymer, maleic anhydride graft-propylene-ethylene copolymer, chlorinated polyethylene, chlorinated polypropylene, EPDM, phenolic resin, silicone resin, epoxy resin, etc. Mention may be made of the above.

  The method for preparing the aqueous liquid of the present invention is not particularly limited. For example, each polymer is dissolved in water, and the aqueous liquid of each polymer and, if necessary, the silica component are mixed. A method of adding a silica component if necessary, a method of polymerizing each monomer in an aqueous polyvinyl alcohol solution, neutralizing with an alkali, and adding a silica component if necessary It can be prepared by the method. In the above case, the mixture may be prepared using a solvent other than water, such as alcohols.

For applying the aqueous liquid of the present invention to the base film, a known coating method is appropriately adopted. For example, any method such as a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, a coating method using a spray or a brush can be used. Moreover, you may immerse a base film in the aqueous liquid of this invention. From the viewpoint of cost, the aqueous liquid of the present invention may be applied by a so-called in-line coating method in which a film is coated in the film production process. Specifically, for example, in the production of the coating film, the base film resin is extruded, for example, while being used in combination with an electrostatic adhesion method or the like, cast on a cooling drum to obtain a sheet, and then stretched in the longitudinal direction. Next, a method of stretching the film in the lateral direction after applying the aqueous liquid to one side of the film after the longitudinal stretching can be used.
In the present invention, after the application, moisture can be evaporated using a known drying method such as heat drying such as hot air drying or hot roll drying at a temperature of about 80 to 200 ° C. or infrared drying. Thereby, a laminated film having a uniform coating layer is obtained.

In the laminated film of the present invention, the thickness of the resin layer is not particularly limited, but is usually 0.0005 μm or more, preferably 0.001 μm or more, more preferably 0.01 μm or more, and usually 1 μm. The thickness is preferably 0.5 μm or less, more preferably 0.5 μm or less, and still more preferably 0.2 μm or less. If the thickness is 1 μm or less, the slipperiness is good, there is almost no peeling from the substrate film due to the internal stress of the resin layer itself, and there is little residual solvent component in the resin layer itself, and a high-quality inorganic thin film Can be formed. If the thickness is 0.0005 μm or more, the uniform thickness can be maintained, the flatness of the base film can be improved, and the adhesion between the base film and the inorganic thin film can be further improved. It is preferable in that precipitation and volatilization of low molecular weight substances can be suppressed and a high-quality inorganic thin film can be formed. From the above points, the thickness of the resin layer is preferably 0.0005 to 1 μm, more preferably 0.001 to 0.5 μm, and further preferably 0.001 to 0.2 μm.
As will be described later, when the resin layer is provided between the inorganic thin films, it is preferably from 0.0005 to 1 μm, more preferably from the viewpoint of adhesion between layers, cohesive fracture resistance, gas barrier properties, and the like. It is 0.001-0.5 micrometer, More preferably, it is larger than 0.01 micrometer and 0.5 micrometer or less.
In order to improve water resistance and durability, the resin layer can be subjected to a crosslinking treatment by electron beam irradiation. Moreover, in order to improve the applicability | paintability and adhesiveness of the said resin layer to a base film, you may give surface treatments, such as a normal chemical treatment and electrical discharge treatment, to a film before application | coating of the aqueous liquid of this invention.

  In the present invention, gas barrier properties and adhesion between layers can be improved by applying the aqueous liquid of the present invention on a base film and providing a resin layer between the inorganic thin film. The reason for this is that by applying an aqueous liquid and providing a resin layer, surface precipitation of low boiling point compounds and low molecular weight compounds from the base film is suppressed and / or covered, and adhesion to the inorganic thin film and its denseness are reduced. Improving adhesion, improving adhesion by chemical adsorption between the functional groups of the resin layer and the inorganic thin film, improving the surface flatness of the base film to form the inorganic thin film uniformly and finely, the resin layer itself And the like can be added to the laminated film.

In the present invention, an inorganic thin film is formed on the resin layer. Examples of the inorganic substance constituting the inorganic thin film include silicon, aluminum, magnesium, zinc, tin, nickel, titanium, hydrocarbon, and the like, or oxides, carbides, nitrides, or a mixture thereof. It is a diamond-like carbon mainly composed of silicon, aluminum oxide and hydrocarbon. In particular, silicon oxide and aluminum oxide are preferable in that high gas barrier properties can be stably maintained.
As a method for forming the inorganic thin film, any method such as a vapor deposition method and a coating method can be used, but the vapor deposition method is preferable in that a uniform thin film having a high gas barrier property can be obtained. This vapor deposition method includes methods such as vacuum vapor deposition, ion plating, sputtering, and CVD.
The thickness of the inorganic thin film is generally 0.1 to 500 nm, but preferably 0.5 to 40 nm. If it is in the said range, sufficient gas-barrier property will be acquired, and it will be excellent also in transparency, without generating a crack and peeling in an inorganic thin film.

As the gas barrier laminate film of the present invention, various gas barrier laminate films having additional constituent layers as necessary in the constituent layers described above can be used depending on applications. Specifically, a layer made of the following resin can be provided between the base film and the resin layer or between the resin layer and the inorganic thin film in order to further improve the gas barrier property. Such resins include solvent-based or water-soluble polyester resins, isocyanate resins, urethane resins, acrylic resins, vinyl alcohol resins, ethylene vinyl alcohol resins, vinyl modified resins, epoxy resins, oxazoline group-containing resins, modified styrene resins, modified resins. Silicon resins and alkyl titanates can be used alone or in combination of two or more. Among these, polyester resins, urethane resins, acrylic resins, and oxazoline group-containing resins are preferable.
Various well-known additives can be mix | blended with said resin layer. Examples of the additive include an antioxidant, a weather resistance stabilizer, an ultraviolet absorber, an antistatic agent, a pigment, a dye, an antibacterial agent, a lubricant, an inorganic filler, an antiblocking agent, and an adhesive.
The layer can be provided in a thickness of 0.0005 to 1 μm, further 0.001 to 0.5 μm, and further 0.001 to 0.2 μm.

  In addition, as the gas barrier laminate film of the present invention, the same resin layer and inorganic thin film as described above can be formed on the inorganic thin film from the viewpoints of gas barrier properties, interlayer adhesion, and the like. The thin film can be further repeatedly formed. That is, the laminate film of the present invention can have two or more constituent layer units composed of the resin layer and an inorganic thin film formed on the resin layer. In the present invention, from the viewpoint of productivity, the total number of the constituent layer units is preferably 1 to 3, more preferably 1 or 2.

A protective layer is preferably formed on the inorganic thin film formed on the substrate in order to protect the inorganic thin film and improve the adhesiveness.
As the protective layer, solvent-based or water-soluble polyester resin, isocyanate resin, urethane resin, acrylic resin, nitrocellulose resin, silicon resin, vinyl alcohol resin, EVOH resin, ethylenically unsaturated carboxylic acid resin, ionomer resin, silicon resin, Examples of the layer include a vinyl-modified resin, an epoxy resin, an oxazoline group-containing resin, a modified styrene resin, a modified silicon resin, and an alkyl titanate alone or in combination of two or more. Further, as the protective layer, a layer formed by mixing at least one kind of inorganic particles selected from silica sol, alumina sol, particulate inorganic filler, and layered inorganic filler with the resin for improving barrier properties, wearability, and slipperiness. Alternatively, a layer made of an inorganic particle-containing resin formed by polymerizing the resin raw material in the presence of the inorganic particles can also be used.
Furthermore, for the protective layer, known additives such as antistatic agents, light blocking agents, ultraviolet absorbers, plasticizers, fillers, colorants, stabilizers, antifoaming agents, crosslinking agents, antiblocking agents, antioxidants An agent or the like can be added.

  Moreover, as a normal embodiment, a gas barrier laminate film in which a plastic film is provided on the inorganic thin film surface is used for various applications. The thickness of the plastic film is usually 5 to 500 μm, preferably 10 to 200 μm, depending on the application, from the viewpoints of mechanical strength, flexibility, transparency as a substrate of the laminated structure. . Further, the width and length of the film are not particularly limited and can be appropriately selected according to the intended use. For example, by using a resin capable of heat sealing on the inorganic thin film surface, heat sealing becomes possible and it can be used as various containers. Examples of the resin that can be heat sealed include known resins such as polyethylene resin, polypropylene resin, ethylene-vinyl acetate copolymer, ionomer resin, acrylic resin, and biodegradable resin.

Moreover, as an embodiment of the gas barrier laminate film other than those described above, there may be mentioned one in which a printed layer is formed on the inorganic thin film surface and a heat seal layer is further laminated thereon. As the printing ink for forming the printing layer, aqueous and solvent-based resin-containing printing inks can be used. Here, examples of the resin used in the printing ink include acrylic resins, urethane resins, polyester resins, vinyl chloride resins, vinyl acetate copolymer resins, and mixtures thereof. Furthermore, for printing inks, antistatic agents, light shielding agents, ultraviolet absorbers, plasticizers, lubricants, fillers, colorants, stabilizers, lubricants, antifoaming agents, crosslinking agents, antiblocking agents, antioxidants, etc. These known additives may be added.
Although it does not specifically limit as a printing method for providing a printing layer, Well-known printing methods, such as an offset printing method, a gravure printing method, and a screen printing method, can be used. For drying the solvent after printing, a known drying method such as hot air drying, hot roll drying, or infrared drying can be used.
It is also possible to laminate at least one paper or plastic film between the printing layer and the heat seal layer. As a plastic film, the thing similar to the thermoplastic polymer film as a base film used for the gas barrier laminate film of the present invention can be used. Among these, paper, polyester resin, polyamide resin or biodegradable resin is preferable from the viewpoint of obtaining sufficient rigidity and strength of the laminate.

In the present invention, after the resin layer is formed and / or the inorganic thin film is formed, it is preferable to perform heat treatment from the viewpoints of gas barrier properties, film quality, and coating layer quality stabilization.
The heat treatment has different conditions depending on the type and thickness of the elements constituting the gas barrier film, but is not particularly limited as long as it can maintain the necessary temperature and time. For example, a method of storing in an oven or temperature-controlled room set to the required temperature, a method of blowing hot air, a method of heating with an infrared heater, a method of irradiating light with a lamp, or heating directly by contact with a hot roll or hot plate A method of imparting a light, a method of irradiating with a microwave, or the like can be used. Moreover, even if it heat-processes, after cutting a film into the magnitude | size which is easy to handle, it may heat-process with a film roll. Furthermore, as long as the necessary time and temperature can be obtained, a heating device can be incorporated in a part of a film manufacturing apparatus such as a coater or a slitter, and heating can be performed in the manufacturing process.

  The temperature of the heat treatment is not particularly limited as long as it is a temperature below the melting point of the base material, plastic film, etc. to be used, but it is 60 ° C. or higher because the treatment time necessary for the effect of heat treatment can be set appropriately. It is preferable to carry out at 70 ° C. or higher. The upper limit of the heat treatment temperature is usually 200 ° C., preferably 160 ° C., from the viewpoint of preventing deterioration of gas barrier properties due to thermal decomposition of the elements constituting the gas barrier laminate film. The treatment time depends on the heat treatment temperature, and is preferably shorter as the treatment temperature is higher. For example, when the heat treatment temperature is 60 ° C., the treatment time is about 3 days to 6 months, when it is 80 ° C., the treatment time is about 3 hours to 10 days, and when it is 120 ° C., the treatment time is about 1 hour to 1 day. In the case of 150 ° C., the processing time is about 3 to 60 minutes, but these are merely guidelines and can be appropriately adjusted depending on the type and thickness of the elements constituting the gas barrier laminate film.

The method for producing a gas barrier laminate film of the present invention comprises (A) (a) polyvinyl alcohol and (b) an ethylene / unsaturated carboxylic acid copolymer on at least one surface of (A) a base film. A step of applying an aqueous liquid obtained by mixing, and (B) a step of forming an inorganic thin film by a vapor deposition method on the resin layer obtained by applying the aqueous liquid.
(A) As a step of applying an aqueous liquid obtained by mixing (a) polyvinyl alcohol and (b) an ethylene / unsaturated carboxylic acid copolymer onto the inorganic thin film surface, the above-mentioned (a) Each of the component and the component (b) can be used, and such an aqueous liquid is prepared by the above-described method, and this is applied onto the surface of the inorganic thin film. At this time, the ethylene / unsaturated carboxylic acid copolymer is preferably used as an aqueous liquid containing the ethylene / unsaturated carboxylic acid copolymer and an aqueous medium composed of ammonia or an alkali metal hydroxide. In addition, as described above, a uniform thin film having a high gas barrier property can be obtained by the step of (B) forming an inorganic thin film on at least one surface of the base film by vapor deposition. As this vapor deposition method, any method such as vacuum vapor deposition, ion plating, sputtering, and CVD can be used.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following examples. In addition, the evaluation method of the film in the following examples is as follows.
<Water vapor transmission rate>
According to the conditions of JIS Z0222 “moisture-proof packaging container moisture permeability test method” and JIS Z0208 “moisture-proof packaging material moisture permeability test method (cup method)”, the following methods were used for evaluation.
Using two gas barrier laminated films each having a moisture permeable area of 10.0 cm × 10.0 cm square, a bag having about 20 g of anhydrous calcium chloride as a hygroscopic agent and sealed on all sides was produced, and the bag was heated to a temperature of 40 ° C. and a relative humidity of 90 As a guideline, the weight increase was almost constant at intervals of 48 hours or longer, and mass measurement (0.1 mg unit) was performed up to 14 days, and the water vapor transmission rate was calculated from the following formula.
Water vapor transmission rate (g / m ² / 24h) = (m / s) / t
m: Mass increase in the last two weighing intervals (g)
s; Moisture permeable area (m ² )
t: Time of last two weighing intervals (h) / 24 (h)

<Interlayer adhesion strength>
In accordance with JIS Z1707, the laminated film is cut into a strip shape having a width of 15 mm, part of the unstretched polypropylene film at the end and the gas barrier laminate film is peeled off, and the T-type is peeled off at a rate of 100 mm / min by a peel tester. Peeling was performed, and the laminate strength (g / 15 mm) was measured.

In addition, the preparation method of each aqueous liquid is as follows.
<Preparation of PVA aqueous liquid (a)>
An aqueous liquid (a) having a solid content concentration of 10% was prepared using polyvinyl alcohol (PVA, “Poval N-300” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., saponification degree of 98% or more) and ion-exchanged water.

<Preparation of aqueous solution of ethylene / unsaturated carboxylic acid copolymer (b-1)>
Ethylene / acrylic acid copolymer (EAA) (acrylic acid 20% by mass, MFR: 300 g / 10 min), ammonia and ion-exchanged water are stirred and mixed at 95 ° C. for 2 hours, and the degree of neutralization is 75% and the solid content is 20%. An aqueous liquid (b-1) was prepared.
<Preparation of ethylene / unsaturated carboxylic acid copolymer aqueous liquid (b-2)>
Ethylene / methacrylic acid copolymer (EMAA) (methacrylic acid 20% by mass, MFR: 300 g / 10 min), sodium hydroxide, and ion-exchanged water are stirred and mixed at 95 ° C. for 2 hours, and the degree of neutralization is 80%. A 20% aqueous solution (b-2) was prepared.

<Preparation of silica component aqueous liquid (c-1)>
An aqueous silica particle liquid (c-1) was prepared according to the description in paragraphs [0012] to [0031] of JP-A-6-16414. That is, sodium water glass JIS3 was dissolved in a sodium nitrate aqueous solution to prepare a sodium silicate aqueous solution, which was passed through a hydrogen-type cation exchange resin column, a hydroxyl-type anion exchange resin column, and a hydrogen-type cation exchange resin column in this order, An aqueous sodium oxide solution was added to obtain an aqueous silicic acid solution. Next, 20% of the silicic acid aqueous solution was distilled under reduced pressure to remove the evaporated water, and the remaining silicic acid aqueous solution was continuously fed gradually to carry out the vacuum distillation continuously to produce a colloidal silica sol. Further, the colloidal silica sol is passed through a hydrogen-type cation exchange resin column, a hydroxyl group-type anion exchange resin column, and a hydrogen-type cation exchange resin column in this order, and immediately after that, special grade ammonia water is added, pH 9, average particle diameter 4 nm, various metals An aqueous silica sol (c-1) having an oxide concentration of less than 500 ppm was obtained.
<Preparation of silica component aqueous liquid (c-2)>
Dilute hydrochloric acid was added to tetraethoxysilane and stirred for 30 minutes to obtain a hydrolysis-condensation product liquid (c-2).

Reference Examples 1, 2, 4, Example 3 and Comparative Examples 1, 2
A polyethylene terephthalate resin (hereinafter abbreviated as PET; “NOVAPEX” manufactured by Mitsubishi Chemical Corporation) is melt extruded to form a sheet, stretched in the longitudinal direction at a stretching temperature of 95 ° C. and a stretching ratio of 3.3, and then stretched at 110 ° C. The film was stretched in the transverse direction at a stretch ratio of 3.3 and subjected to corona treatment to obtain a biaxially stretched PET film having a thickness of 12 μm.
On the other hand, each aqueous liquid prepared by the said content was mixed with the compounding ratio shown in Table 1-1 and Table 2, and various coating liquids were prepared.
This coating solution was applied to the corona-treated surface of the biaxially stretched PET film with a bar coater so as to have a dry thickness of 0.1 μm, and air-dried at 80 ° C. for 2 minutes to obtain a coated film.
Next, SiO was evaporated by a high-frequency heating method under a vacuum of 1 × 10 ⁻⁵ Torr using a vacuum vapor deposition apparatus to form an inorganic thin film having a thin film thickness of about 20 nm on the coated surface of the coated film.
Further, a urethane-based adhesive ("AD900" manufactured by Toyo Morton Co., Ltd. and "CAT-RT85" in a ratio of 10: 1.5) was applied to the inorganic thin film surface of the inorganic thin film, dried, and dried. An adhesive resin layer of about 3 μm was formed, and an unstretched polypropylene film thickness of 60 μm (“Pyrene Film-CTP 1146” manufactured by Toyobo Co., Ltd.) was laminated on this adhesive resin layer to obtain a laminated film. Said evaluation was performed about the obtained laminated | multilayer film. The results are shown in Table 1-1, Table 1-2, and Table 2.

Reference Example 5 and Comparative Example 3
In the production of the coated film of Reference Example 1, a PET resin (“Novapex” manufactured by Mitsubishi Chemical Corporation) was extruded from the die of the extruder at a temperature of 280 to 300 ° C., and on the cooling drum while using the electrostatic adhesion method together. An amorphous polyester sheet having a thickness of about 150 μm was obtained by casting. The above sheet was stretched 3.5 times in the longitudinal direction at 95 ° C., and then each aqueous liquid shown in Table 1-2 and Table 2 was applied to one side of the film after the longitudinal stretching. Further, the film was stretched 3.5 times in the transverse direction at 110 ° C. and heat-treated at 230 ° C., and a biaxially stretched polyester film coated film having a coating layer thickness of 0.1 μm and a base polyester film thickness of 12 μm (Table 1-2 and Table 1-2) (denoted as “inline-coated PET”). Others were produced in the same manner as in Reference Example 1 and evaluated. The results are shown in Table 1-1 and Table 2.

Reference Example 6
In Reference Example 5, the aqueous liquid to be applied was changed to a liquid in which the following resins A, B and C were mixed at a ratio of the solid content mass ratio of 50/20/30 to prepare a coated film of a biaxially stretched polyester film, the aqueous solutions shown in Table 1-2 on the coated surface, except for coating in the same manner as in reference example 1, were prepared evaluated in the same manner as the laminated film as in reference example 1. The results are shown in Table 1-2.

Resin A: As a water-based acrylic resin water-based paint (non-emulsifier type), a water-based acrylic resin water-based paint obtained by the following method was used. That is, 40 parts by mass of ethyl acrylate, 30 parts by mass of methyl methacrylate, 20 parts by mass of methacrylic acid, and 10 parts by mass of glycidyl methacrylate were solution-polymerized in ethyl alcohol, and heated while adding water after polymerization to remove ethyl alcohol. did. The aqueous acrylic resin aqueous paint (non-emulsifier type) was obtained by adjusting the pH to 7.5 with aqueous ammonia.
Resin B: Aqueous polyurethane resin aqueous paint obtained by the following method was used as the aqueous polyurethane resin aqueous paint. That is, first, a polyester polyol comprising 664 parts of terephthalic acid, 631 parts of isophthalic acid, 472 parts of 1,4-butanediol, and 447 parts of neopentyl glycol was obtained. Next, 321 parts of adipic acid and 268 parts of dimethylolpropionic acid were added to the obtained polyester polyol to obtain a pendant carboxyl group-containing polyester polyol A. Further, 160 parts of hexamethylene diisocyanate was added to 1880 parts of the above polyester polyol A to obtain an aqueous polyurethane resin aqueous paint.
Resin C: Nippon Shokubai Co., Ltd. as a 40 mass% solution (water / 1-methoxy-2-isopropanol = 1/2 volume ratio) of an oxazoline group-containing water-soluble polymer (oxazoline group content 4.5 mmol / g) “Epocross WS-500” manufactured by the company was used.

Reference Example 7
To the corona surface of the biaxially stretched PET film produced in Reference Example 1, an isocyanate compound (“Coronate L” manufactured by Nippon Polyurethane Industry) and a saturated polyester (“Byron 300” manufactured by Toyobo Co., Ltd.) were blended in a 1: 1 mass ratio. The mixture was applied with a bar coater to a dry thickness of 0.1 μm, and blown and dried at 80 ° C. for 1 minute to produce a coating film (denoted as “offline coat PET” in Table 1-2). the aqueous solutions shown in Table 1-2 except that applied in the same manner as in reference example 1 was evaluated prepared in the same manner as in reference example 1. The results are shown in Table 1-2.

Example 8
In forming the inorganic thin film of Reference Example 1, instead of depositing silicon oxide, aluminum was evaporated, oxygen gas was supplied using a gas flow rate controller, and deposition was performed at 1 × 10 ⁻⁴ Torr. A laminated film was obtained in the same manner except that an aluminum oxide (alumina) thin film having a thickness of about 20 nm was formed. Said evaluation was performed about the obtained laminated | multilayer film. The results are shown in Table 1-2.

Reference Example 9
In Reference Example 2, after an inorganic thin film was formed, an aqueous liquid for a resin layer having the same composition as in Reference Example 2 was further applied onto the inorganic thin film so that the dry thickness was 0.02 μm, and further on that A laminated film was obtained in the same manner except that the same inorganic thin film as the above inorganic thin film was formed with a thickness of about 20 nm. Said evaluation was performed about the obtained laminated | multilayer film. The results are shown in Table 1-2.

  The gas-barrier laminated film of the present invention is widely used for packaging of articles that need to block various gases such as water vapor and oxygen, for example, packaging for preventing alteration of food, industrial goods, pharmaceuticals, and the like. Moreover, it can use suitably also as a transparent conductive sheet used with a liquid crystal display element, a solar cell, an electromagnetic wave shield, a touch panel, a substrate for EL, a color filter, etc. besides a packaging use.

Claims (11)

Silica particles having an average particle diameter of 1 to 20 nm and having silanol groups as (a) polyvinyl alcohol, (b) ethylene / unsaturated carboxylic acid copolymer, and (c) silica component on at least one surface of the base film A gas barrier laminate film comprising: a resin layer formed by applying an aqueous liquid containing: and an inorganic thin film formed on the resin layer,
The gas barrier laminate film, wherein the content of silica particles as a silica component in the aqueous liquid is 2 to 50% by mass with respect to the total amount of the component (a) and the component (b).   The laminated film according to claim 1, wherein the ethylene / unsaturated carboxylic acid copolymer contains a partially neutralized product of the ethylene / unsaturated carboxylic acid copolymer.   The laminated film according to claim 2, wherein the degree of neutralization of the partially neutralized ethylene / unsaturated carboxylic acid copolymer is 20 to 100 mol%.   The laminated film according to claim 3, wherein the partially neutralized product of the ethylene / unsaturated carboxylic acid copolymer contains an alkali metal ion.   The laminated film according to any one of claims 1 to 4, wherein a content ratio of the polyvinyl alcohol and the ethylene / unsaturated carboxylic acid copolymer is 95: 5 to 5:95 by mass ratio.   The laminated film according to any one of claims 1 to 5, wherein the saponification degree of polyvinyl alcohol is 90% or more.   The laminated film according to any one of claims 1 to 6, wherein the resin layer formed by applying the aqueous liquid has a thickness of 0.0005 to 1 µm.   The laminated film according to any one of claims 1 to 7, wherein the inorganic thin film is made of silicon oxide.   The laminated film according to any one of claims 1 to 8, comprising two or more constituent layer units composed of the resin layer and an inorganic thin film formed on the resin layer. At least on one surface of (A) the base film, (a) polyvinyl alcohol, (b) an ethylene / unsaturated carboxylic acid copolymer, and (c) a silica component having an average particle diameter of 1 to 20 nm and silanol A step of applying an aqueous liquid obtained by mixing the silica particles having a group , and (B) a step of forming an inorganic thin film by a vapor deposition method on the resin layer obtained by applying the aqueous liquid. A method for producing a gas barrier laminate film having:
(A) Content of the silica particle as a silica component in the aqueous liquid of the aqueous liquid apply | coated at a process is 2-50 mass% with respect to the total amount of the said (a) component and (b) component, A method for producing a gas barrier laminate film.   The production method according to claim 10, wherein the ethylene / unsaturated carboxylic acid copolymer is used as an aqueous liquid containing the ethylene / unsaturated carboxylic acid copolymer and an aqueous medium composed of ammonia or an alkali metal hydroxide.