JP7052202B2 - Water-based coating agent and gas barrier film using it - Google Patents

Description

The present invention relates to a water-based coating agent and a gas barrier film using the same.

In the packaging materials used for packaging foods, pharmaceuticals, etc., water vapor, oxygen, and other gases that alter the contents enter in order to suppress deterioration and putrefaction of the contents and maintain their functions and properties. (Gas barrier property) is required. Therefore, conventionally, these packaging materials have been used to have a gas barrier layer.

Until now, the gas barrier layer has been provided on a substrate such as a film or paper by a sputtering method, a vapor deposition method, a wet coating method, a printing method, or the like. The gas barrier layer includes a metal foil made of a metal such as aluminum, a metal vapor deposition film, a water-soluble polymer such as polyvinyl alcohol and an ethylene-vinyl alcohol copolymer, a resin film made of a resin such as polyvinylidene chloride, and the above-mentioned water-soluble. A composite film of a sex polymer and an inorganic layered mineral or the like is used (see, for example, Patent Documents 1 to 5).

However, although the metal foil and the metal vapor-deposited film have excellent gas barrier properties, they are opaque, so that the contents cannot be confirmed, and because they are inferior in elasticity, cracks occur at a stretch of several percent, resulting in gas barrier properties. There are various problems such as a decrease in the amount of metal, and a point that it is necessary to treat it as a non-combustible material at the time of disposal after use. In addition, although the resin film made of polyvinylidene chloride exhibits good gas barrier properties that are not humidity-dependent, it contains chlorine and may be a source of harmful substances such as dioxins during disposal. , There is a tendency to dislike using it as a packaging material. A resin film made of a water-soluble polymer such as a non-chlorine polyvinyl alcohol or an ethylene-vinyl alcohol copolymer exhibits a high gas barrier property in a low humidity atmosphere, but has a humidity dependence on the gas barrier property, and the humidity is high. There was a drawback that the gas barrier property was greatly reduced with the increase. Further, the resin film made of a resin other than polyvinylidene chloride and a water-soluble polymer was inferior in gas barrier property as compared with the resin film of polyvinylidene chloride and the resin film of polyvinyl alcohol in a low humidity atmosphere. Further, the composite film of the water-soluble polymer and the inorganic layered mineral can improve the humidity dependence as compared with the resin film made of the water-soluble polymer. However, there is a problem that the film strength decreases as the compounding ratio of the inorganic layered mineral is increased in order to improve the humidity dependence. In addition, a composite film of a general water-soluble polymer and an inorganic layered mineral has low adhesion to a plastic base material, and in order to obtain practical adhesion strength, it adheres between the plastic base material and the composite film. There was a problem that layers had to be formed.

On the other hand, the film made of a vinyl alcohol-vinyl amine copolymer can have both adhesion to a plastic substrate and gas barrier properties (see Patent Documents 6 to 8). However, in a film simply composed of a vinyl alcohol-vinyl amine copolymer, the humidity dependence of the gas barrier property is severe, and the gas barrier property is greatly reduced as the humidity rises. On the other hand, a technique for reacting a vinyl alcohol-vinylamine copolymer with a specific cross-linking agent has been devised, but the coating suitability is lowered due to the increase in viscosity and the change in the chemical structure due to the cross-linking. , There are problems such as shortened pot life.

Japanese Unexamined Patent Publication No. 2001-287294 Japanese Unexamined Patent Publication No. 11-165369 Japanese Unexamined Patent Publication No. 6-93133 Japanese Unexamined Patent Publication No. 9-150484 Japanese Patent No. 3764109 Japanese Patent No. 3260384 Japanese Patent No. 4889735 Japanese Patent No. 569738

The present invention has been made in view of the above circumstances, and has excellent gas barrier properties even in a high humidity atmosphere, has a long pot life, and has sufficient adhesion strength and film aggregation strength as a packaging material. It is an object of the present invention to provide a water-based coating agent capable of forming a gas barrier film and a gas barrier film using the same.

The present invention is a gas barrier film comprising a substrate and a gas barrier film laminated on at least one surface of the substrate, wherein the gas barrier film is a vinyl alcohol-vinylamine copolymer (A) and an inorganic layered mineral (B). The content of the inorganic layered mineral (B) contained in the gas barrier film is 5% by mass or more, and the mass of the vinyl alcohol-vinylamine copolymer (A) is divided by the mass of the inorganic layered mineral (B). The value is 2/3 or more, and the inorganic layered mineral (B) is characterized by containing a water-swellable synthetic mica .

Further, the content of the inorganic layered mineral (B) contained in the gas barrier membrane is preferably 8% by mass or more and 30% by mass or less.

Further, the gas barrier membrane may further contain polyvinyl alcohol (C).

Further, the present invention is a water-based coating agent containing a vinyl alcohol-vinylamine copolymer (A) and an inorganic layered mineral (B), and the content of the inorganic layered mineral in the total solid content is 5% by mass or more. The value obtained by dividing the mass of the vinyl alcohol-vinylamine copolymer (A) by the mass of the inorganic layered mineral (B) is 2/3 or more, and the inorganic layered mineral (B) forms a water-swellable synthetic mica. It is characterized by including .

According to the present invention, a water-based coating capable of forming a gas barrier film having excellent gas barrier properties even in a high humidity atmosphere, a long pot life, and sufficient adhesion strength and film aggregation strength as a packaging material. An agent and a gas barrier film using the agent can be realized.

Hereinafter, the water-based coating agent of the present invention and the gas barrier film using the same will be described with reference to embodiments. It should be noted that the embodiments shown below are specifically described in order to better understand the gist of the invention, and do not limit the present invention unless otherwise specified.

<Water-based coating agent>
The water-based coating agent according to the present embodiment contains a vinyl alcohol-vinylamine copolymer (A) and an inorganic layered mineral (B).

"Vinyl alcohol-vinyl amine copolymer (A)"
The vinyl alcohol-vinyl amine copolymer (A) typically has the following structure.

ここで、ｍは０モル％以上１５モル％以下であり、ｎは５０％以上９９モル％以下であり、ｘは０モル％以上３０モル％以下であり、ｙは１モル％以上５０モル％以下である。ビニルアルコール－ビニルアミン共重合体（Ａ）がアミノ基を含んでいることで、プラスチック基材への良好な密着性が発現する。

Here, m is 0 mol% or more and 15 mol% or less, n is 50% or more and 99 mol% or less, x is 0 mol% or more and 30 mol% or less, and y is 1 mol% or more and 50 mol% or less. It is as follows. Since the vinyl alcohol-vinyl amine copolymer (A) contains an amino group, good adhesion to a plastic substrate is exhibited.

The method for producing the vinyl alcohol-vinylamine copolymer (A) is not particularly limited, and for example, the production method is disclosed in Japanese Patent No. 4385633, Japanese Patent No. 5669738, Japanese Patent No. 4640886 and the like.

The vinyl alcohol-vinylamine copolymer (A) is usually produced by hydrolyzing a copolymer composed of N-vinylamide units and vinyl acetate units while dispersing it in water under basic conditions. The N-vinylamide unit is obtained from, for example, N-vinylformamide or N-vinylacetamide. During the manufacturing process, vinyl acetate and N-vinylamide are hydrolyzed at a rate of at least about 70% or more, preferably about 90% or more, more preferably about 95% or more. The weight average molecular weight of the obtained copolymer varies depending on various factors. For example, the weight average molecular weight is greater than about 80,000, preferably greater than about 90,000.

In the above production method, the molar ratio of the N-vinylamide unit and the vinyl acetate unit in the copolymer is preferably in the range of 3:97 to 40:60, more preferably 5:95 to 25:75. When the molar ratio of N-vinylamide units in the copolymer is less than 3, the adhesion to the plastic substrate is adversely affected. Further, when the ratio of the molar ratio of the N-vinylamide unit in the copolymer exceeds 40, the gas barrier property of the gas barrier film made of the water-liquid coating agent is lowered. The starting copolymer may further contain any other monomer unit as long as it does not adversely affect the desired properties of the obtained copolymer. The content of other monomers is 30 mol% or less with respect to all the monomer units.

Hydrolysis is carried out under basic conditions. Basic conditions can occur by adding a strong alkali such as caustic alkali. Examples of the caustic alkali include caustic soda and caustic potash. The amount of alkali added is usually 0.1 equivalent or more and 10 equivalent or less, preferably 0.5 equivalent or more and 5 equivalent or less, per total monomer equivalent.

At the end of hydrolysis, the reaction mixture is usually slurry. The slurry is cooled and the solids are separated from the reaction by appropriate means. The recovered polymer is then washed to remove impurities. Cleaning is performed using a cleaning solution containing at least one selected from 1) alcohol, 2) cooling water at 20 ° C. or lower, and 3) salt water to remove impurities in the polymer.

As the vinyl alcohol-vinyl amine copolymer (A), various commercially available products can also be used. For example, DIAFIX commercially available from Mitsubishi Chemical Corporation and Ultrac (registered trademark) commercially available from Sekisui Specialty Chemicals Corporation can be used.

"Inorganic layered mineral (B)"
The "inorganic layered mineral" refers to an inorganic compound in which ultra-thin unit crystal layers are overlapped to form one layered particle. The inorganic layered mineral (B) is used for the purpose of imparting further gas barrier properties to the vinyl alcohol-vinyl amine copolymer. As the inorganic layered mineral (B), a compound that swells and / or cleaves in water is preferable, and a clay compound having swellability to water is particularly preferable. More specifically, the inorganic layered mineral (B) is preferably a clay compound having the property of coordinating water between ultrathin unit crystal layers and absorbing and / or swelling. In general, such clay compounds have a layer in which Si ⁴⁺ coordinates with respect to O ^2- to form a tetrahedral structure, and Al ³⁺ , Mg ²⁺ , Fe ²⁺ , Fe ³⁺ and the like become O ^2- and OH ⁻ . It is a compound in which layers that are coordinated to each other to form an octahedral structure are bonded in a one-to-one or two-to-one manner and are stacked to form a layered structure. This clay compound may be a natural compound or a synthesized compound.

Typical examples of the inorganic layered mineral (B) include hydrous silicates such as phyllosilicate minerals, and for example, kaolinite clay minerals such as halloysite, kaolinite, enderite, dikite, and naphthite; anti. Anti-Golite clay minerals such as golite and chrysotile; Smectite clay minerals such as montmorillonite, byderite, nontronite, saponite, hectrite, soconite and stibunsite; vermiculite clay minerals such as vermiculite; white mica, gold mica, Examples thereof include mica or mica-type clay minerals such as margarite, tetrasilic mica, and teniolite. These inorganic layered minerals (B) are used alone or in combination of two or more. Among these inorganic layered minerals (B), smectite group clay minerals such as montmorillonite and mica group clay minerals such as water-swellable mica are preferable.

The size of the inorganic layered mineral (B) is preferably such that the average particle size is 10 μm or less and the thickness is 500 nm or less. When the average particle size and the thickness are each equal to or less than the above upper limit values, the inorganic layered mineral (B) is likely to be uniformly aligned in the film, and the gas barrier property and the film cohesive strength are high. The average particle size of the inorganic layered mineral (B) is measured by a laser diffraction type particle size distribution meter. The thickness of the inorganic layered mineral (B) is measured by an atomic force microscope (AFM).

The inorganic layered mineral (B) more preferably contains at least a water-swellable synthetic mica, and may contain a water-swellable synthetic mica having an average particle size of 1 μm or more and 10 μm or less and a thickness of 10 nm or more and 100 nm or less. Especially preferable. The water-swellable synthetic mica has a high affinity for the vinyl alcohol-vinylamine copolymer (A) and has less impurities than the natural mica. Therefore, when water-swellable synthetic mica is used as the inorganic layered mineral (B), it is unlikely that the gas barrier property and the film cohesive force due to impurities are lowered. Further, since the water-swellable synthetic mica has a fluorine atom in the crystal structure, it also contributes to suppressing the humidity dependence of the gas barrier property of the gas barrier film formed from the water-based coating agent to be low. In addition, the water-swellable synthetic mica has a higher aspect ratio than other water-swellable inorganic layered minerals, so that the maze effect works more effectively and the gas barrier film formed from the water-based coating agent. Contributes to the development of particularly high gas barrier properties.

The water-based coating agent containing the vinyl alcohol-vinylamine copolymer (A) and the inorganic layered mineral (B) as main constituents has a mass ratio of the vinyl alcohol-vinylamine copolymer (A) to the inorganic layered mineral (B). It must be 40/60 or more, and the content of the inorganic layered mineral (B) in the total solid content must be 5% by mass or more. When the mass ratio of the vinyl alcohol-vinylamine copolymer (A) to the inorganic layered mineral (B) is less than 40/60, the interaction between the vinyl alcohol-vinylamine copolymer (A) and the inorganic layered mineral (B) occurs. It is overexpressed, the water-based coating agent rapidly thickens, and the coatability is lost. In addition, the adhesion to the plastic substrate is also lost. Further, when the content of the inorganic layered mineral (B) in the total solid content is less than 5% by mass, the maze effect of the inorganic layered mineral (B) is weakened and the gas barrier property is lowered.

The water-based coating agent containing the vinyl alcohol-vinylamine copolymer (A) and the inorganic layered mineral (B) as main constituents has an inorganic layered mineral (B) content of 8% by mass or more in the total solid content of 30% by mass or more. It is preferably mass% or less. When the content of the inorganic layered mineral (B) in the total solid content is 8% by mass or more, the gas barrier property of the gas barrier film formed from the water-based coating agent is further improved. Further, when the content of the inorganic layered mineral (B) in the total solid content is 30% or less, the cohesive strength of the gas barrier film formed from the water-based coating agent is improved, and when the gas barrier film is bonded to another film, the cohesive strength is improved. Peeling strength is improved. Further, the content of the inorganic layered mineral (B) in the total solid content is more preferably 10% by mass or more and 27% by mass or less, and particularly preferably 12% by mass or more and 24% by mass or less. When the content of the inorganic layered mineral (B) in the total solid content is 12% by mass or more and 24% by mass or less, the coating suitability of the water-based coating agent is better, and the gas barrier property and the cohesive strength are improved. Can obtain a better gas barrier film.

"Polyvinyl alcohol (C)"
In order to form a gas barrier film having better gas barrier properties, it is preferable that the water-based coating agent contains at least one polyvinyl alcohol (C) selected from the group consisting of a polyvinyl alcohol-based polymer and a derivative thereof. Examples of the derivative of the polyvinyl alcohol-based polymer include a graft polymer in which a monomer is graft-polymerized on the side chain of polyvinyl alcohol. It is particularly preferable to contain polyvinyl alcohol (C) having a saponification degree of 95% or more and a polymerization degree of 300 or more. The degree of polymerization of polyvinyl alcohol (C) is preferably 300 or more and 2400 or less, and particularly preferably 450 or more and 2000 or less. The higher the degree of saponification and the degree of polymerization of polyvinyl alcohol (C), the lower the hygroscopicity and swelling property, and the higher the gas barrier property. If the saponification degree of polyvinyl alcohol (C) is less than 95%, sufficient gas barrier properties may not be obtained. If the degree of polymerization of polyvinyl alcohol (C) is less than 300, the gas barrier property and the film cohesive strength may be lowered. On the other hand, if the degree of polymerization of polyvinyl alcohol (C) exceeds 2400, the viscosity of the coating agent increases and it becomes difficult to uniformly mix it with other components, which may lead to problems such as deterioration of gas barrier property and adhesion strength. be.

The aqueous coating agent containing the vinyl alcohol-vinylamine copolymer (A), the inorganic layered mineral (B) and the polyvinyl alcohol (C) as the main constituents is the inorganic layered mineral (A) of the vinyl alcohol-vinylamine copolymer (A). The mass ratio to B) must be 40/60 or more, and the content of the inorganic layered mineral (B) in the total solid content must be 5% by mass or more. When the mass ratio of the vinyl alcohol-vinylamine copolymer (A) to the inorganic layered mineral (B) is less than 40/60, the interaction between the vinyl alcohol-vinylamine copolymer (A) and the inorganic layered mineral (B) occurs. It is overexpressed, the water-based coating agent rapidly thickens, and the coatability is lost. In addition, the adhesion to the plastic substrate is also lost. Further, when the content of the inorganic layered mineral (B) in the total solid content is less than 5% by mass, the maze effect of the inorganic layered mineral (B) is weakened and the gas barrier property is lowered.

The water-based coating agent containing a vinyl alcohol-vinyl amine copolymer (A), an inorganic layered mineral (B) and polyvinyl alcohol (C) as main constituents contains the inorganic layered mineral (B) in the total solid content. Is preferably 8% by mass or more and 30% by mass or less. When the content of the inorganic layered mineral (B) in the total solid content is 8% by mass or more, the gas barrier property of the gas barrier film formed from the water-based coating agent is further improved. Further, when the content of the inorganic layered mineral (B) in the total solid content is 30% or less, the cohesive strength of the gas barrier film formed from the water-based coating agent is improved, and when the gas barrier film is bonded to another film, the cohesive strength is improved. Peeling strength is improved. Further, the content of the inorganic layered mineral (B) in the total solid content is more preferably 10% by mass or more and 27% by mass or less, and particularly preferably 12% by mass or more and 24% by mass or less. When the content of the inorganic layered mineral (B) in the total solid content is 12% by mass or more and 24% by mass or less, a gas barrier film having a long pot life and good gas barrier properties and cohesive strength can be obtained. ..

A water-based coating agent containing a vinyl alcohol-vinyl amine copolymer (A), an inorganic layered mineral (B), and polyvinyl alcohol (C) as main constituents has a polyvinyl alcohol (C) content in the total solid content. It is preferably 10% by mass or more. When the content of polyvinyl alcohol (C) in the total solid content is 10% by mass or more, the gas barrier property of the gas barrier film formed from the water-based coating agent becomes better. The content of polyvinyl alcohol (C) in the total solid content is more preferably 15% by mass or more, and particularly preferably 20% by mass or more.

The water-based coating agent containing the vinyl alcohol-vinyl amine copolymer (A), the inorganic layered mineral (B) and the polyvinyl alcohol (C) as main constituents is particularly preferably one that satisfies the following conditions.
-The mass ratio of the vinyl alcohol-vinyl amine copolymer (A) to the inorganic layered mineral (B) is 40/60 or more.
-The content of the inorganic layered mineral (B) in the total solid content is 12% by mass or more and 24% by mass or less.
-The content of polyvinyl alcohol (C) in the total solid content is 20% by mass or more.

When the ratio of the content of the vinyl alcohol / vinylamine copolymer (A), the inorganic layered mineral (B) and the polyvinyl alcohol (C) in the total solid content is within the above-mentioned predetermined range, the pot life can be used. It is possible to obtain a gas barrier film having a long length and particularly good gas barrier property and cohesive strength.

In addition to the above-mentioned main components, various components can be added as needed in the water-based coating agent according to the present embodiment. For example, addition of antioxidants, weather resistant agents, heat stabilizers, lubricants, crystal nucleating agents, ultraviolet absorbers, plasticizers, antistatic agents, colorants, fillers, defoamers, silane coupling agents, surfactants, etc. Agents are mentioned.

<Gas barrier film>
The gas barrier film according to the present embodiment is characterized by comprising a base film made of a plastic material and a gas barrier film laminated on at least one surface of the base film and formed from the above-mentioned water-based coating agent.

Examples of the plastic material constituting the base film include olefin resins such as polyC2-10 olefins such as polyethylene, polypropylene and propylene-ethylene copolymer; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; nylon 6. , Polyamide-based resins such as aliphatic polyamides of nylon 66 and aromatic polyamides such as polymethoxylylen adipamide; polystyrene, polyvinyl acetate, ethylene-vinyl acetate copolymers, polyvinyl alcohols, ethylene-vinyl alcohol copolymers. Vinyl-based resins such as; acrylic resins such as polymethylmethacrylate, polyacrylonitrile and other (meth) acrylic monomers alone or copolymers; cellophane and the like. These resins may be used alone or in combination of two or more.

Examples of the base film include a single-layer film composed of a single resin, a single-layer film using a plurality of resins, a laminated film, and the like. Further, a laminated base material obtained by laminating the above resin on another base material (metal, wood, paper, ceramics, etc.) may be used. As the base film, a polyolefin-based resin film (particularly, a polypropylene film or the like), a polyester-based resin film (particularly, a polyethylene terephthalate-based resin film), a polyamide-based resin film (particularly, a nylon film) or the like is preferable.

The base film may be an unstretched film or a uniaxial or biaxially stretched oriented film. Further, the base film is used to improve the wettability to the water-based coating agent and the adhesive strength to the gas barrier film on the surface on which the gas barrier film formed from the water-based coating agent is laminated (the surface to which the water-based coating agent is applied). May be subjected to surface treatment such as corona treatment and low temperature plasma treatment. Further, in the base film, the surface on which the gas barrier film formed from the water-based coating agent is laminated may be subjected to an anchor coating treatment or an undercoat treatment.

The thickness of the base film is not particularly limited, and is appropriately selected depending on the price and application while considering the suitability as a packaging material and the stacking suitability of other laminated films, but practically 3 μm or more. It is 200 μm or less, preferably 5 μm or more and 120 μm or less, and more preferably 10 μm or more and 100 μm or less.

The gas barrier film in the gas barrier film according to the present embodiment is formed by applying the water-based coating agent according to the present embodiment on one side (one side) or both sides of the base film to form a coating film made of the water-based coating agent. , Can be formed by drying the coating film.

As a method for applying the water-based coating agent, a known wet coating method can be used. Examples of the wet coating method include roll coating, gravure coating, reverse coating, die coating, screen printing, and spray coating. Further, as a method for drying the coating film made of a water-based coating agent, known drying methods such as hot air drying, hot roll drying, and infrared irradiation can be used.

The thickness of the gas barrier film in the gas barrier film according to the present embodiment, that is, the thickness of the coating film made of an aqueous coating agent after drying is set according to the required gas barrier property, but is 0.1 μm or more and 5 μm. It is preferably 0.2 μm or more and 2 μm or less, more preferably 0.3 μm or more and 1 μm or less. When the thickness of the gas barrier film made of the water-based coating agent is 0.1 μm or more, sufficient gas barrier properties can be easily obtained. When the thickness of the gas barrier film formed from the water-based coating agent is 5 μm or less, it is easy to form a uniform coating film surface, and the drying load and the manufacturing cost can be suppressed.

The gas barrier film according to the present embodiment further includes a printing layer, an anchor coat layer, an overcoat layer, a light shielding layer, an adhesive layer, a heat-sealing heat-sealing layer, and other functional layers, if necessary. You may be doing it.

When the gas barrier film according to the present embodiment has a heat-sealing heat-sealing layer, the heat-sealing layer is arranged on the outermost surface layer of at least one surface of the gas barrier film. Since the gas barrier film has a heat-sealing layer, the contents can be sealed by heat-sealing the gas barrier film. For the heat-sealing layer, for example, a known dry laminating method or extrusion laminating method is used on the outermost surface of the gas barrier film according to the present embodiment, using known adhesives such as polyurethane-based, polyester-based, and polyether-based. It can be laminated by such as.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples. The materials used in each of the following examples are shown below.

<Base film>
Biaxially stretched polyethylene terephthalate film: Commercial product (trade name: P-60, manufactured by Toray Industries, Inc., thickness: 12 μm). Hereinafter referred to as PET.
Biaxially stretched polypropylene film: Commercial product (trade name: PJ201, manufactured by AJ Plast, thickness: 20 μm). Hereinafter referred to as OPP.

<Water-based coating agent>
"Vinyl alcohol-vinyl amine copolymer (A)"
(A): Vinyl alcohol-vinylamine copolymer resin manufactured by Sekisui Specialty Chemicals Co., Ltd. (trade name: Ultrac (registered trademark) 5003).

"Inorganic layered mineral (B)"
(B1): Water-swellable synthetic mica (trade name: Somasif (registered trademark) MEB-3, manufactured by CO-OP CHEMICAL CO., LTD.).
(B2): Montmorillonite (trade name: Kunipia (registered trademark) F, manufactured by Kunimine Kogyo Co., Ltd.).
(B3): Sodium hectorite (trade name: NHT sol B2, manufactured by Topy Industries, Ltd.).

"Polyvinyl alcohol (C)"
(C): Polyvinyl alcohol having a saponification degree of 98 to 99% and a polymerization degree of 500 (trade name: Poval PVA-105, manufactured by Kuraray Co., Ltd.).

<Examples 1 to 13>
A water-based coating agent was prepared so that the final solid content concentration was 6.0% by mass with the types and blending ratios (% by mass) shown in Table 1. First, a predetermined amount of vinyl alcohol-vinyl amine copolymer resin (A) and polyvinyl alcohol (C) were mixed and dissolved by stirring at 90 ° C. for 1 hour. Then, the liquid temperature was lowered to room temperature, the inorganic layered mineral (B) was added, and then diluted with isopropanol so that 10% by mass in the total aqueous medium became isopropanol. As a result, the water-based coating agents of Examples 1 to 13 were prepared respectively. Here, the blending ratio is the ratio of the solid content of each component to the total solid content, and the same applies to the following.

Next, a gas barrier film was prepared using the water-based coating agents of Examples 1 to 13. First, using a gravure printing machine, the water-based coating agents according to Examples 1 to 13 produced were applied to the corona-treated surface of the base film shown in Table 1 to form a coating film. Next, this coating film was dried to form a gas barrier film, and the gas barrier film according to Examples 1 to 13 was obtained. The thickness of the formed gas barrier film was 0.4 μm in all cases when confirmed and measured by an electron microscope.

<Comparative Examples 1 to 6>
A water-based coating agent was prepared so that the final solid content concentration was 6.0% by mass with the types and blending ratios (% by mass) shown in Table 2. First, a predetermined amount of vinyl alcohol-vinyl amine copolymer resin (A) and polyvinyl alcohol (C) were mixed and dissolved by stirring at 90 ° C. for 1 hour. Then, the liquid temperature was lowered to room temperature, the inorganic layered mineral (B) was added, and then diluted with isopropanol so that 10% by mass in the total aqueous medium became isopropanol. As a result, the water-based coating agents of Comparative Examples 1 to 6 were prepared.

Next, a gas barrier film was prepared using the water-based coating agents of Comparative Examples 1 to 6. First, using a gravure printing machine, the water-based coating agents according to Comparative Examples 1 to 6 produced were applied to the corona-treated surface of the base film shown in Table 2 to form a coating film. Next, this coating film was dried to form a gas barrier film, and the gas barrier film according to Comparative Examples 1 to 6 was obtained. The thickness of the formed gas barrier film was 0.4 μm in all cases when confirmed and measured by an electron microscope.

<Comparative Example 7>
Polycup172 (manufactured by Ashland), which is an adduct of epichlorohydrin, was prepared as a cross-linking agent. A water-based coating agent was prepared so that the final solid content concentration was 6.0% by mass at the blending ratio (% by mass) shown in Table 2. First, a predetermined amount of the vinyl alcohol-vinyl amine copolymer resin (A) was added, and the mixture was dissolved by stirring at 90 ° C. for 1 hour. Then, the liquid temperature was lowered to room temperature, and then diluted with isopropanol so that 10% by mass in the total aqueous medium became isopropanol. Then, Polycup 172 was added in a predetermined amount. As a result, the water-based coating agent of Comparative Example 7 was prepared. Next, using the water-based coating agent of Comparative Example 7, the gas barrier film of Comparative Example 7 was prepared by the same procedure as in Comparative Examples 1 to 6.

<Evaluation>
(1) Viscosity of coating liquid The water-based coating agents obtained in Examples 1 to 13 and Comparative Examples 1 to 7 were coated using a vibration viscometer (trade name: VM-1A-MH, manufactured by Yamaichi Denki Kogyo Co., Ltd.). The liquid viscosity was measured. Measurements were taken 1 hour and 1 month after all the ingredients were blended. The evaluation results are shown in Tables 1 and 2.

(2) Oxygen gas barrier property The gas barrier properties obtained in Examples 1 to 13 and Comparative Examples 1 to 7 were measured at 30 ° C. using an oxygen permeability measuring device (trade name: OXTRAN-2 / 20, manufactured by MOCON). , Oxygen permeability (cm ³ / (m ² · day · MPa): OTR) was measured under an atmosphere of 70% RH. The evaluation results are shown in Tables 1 and 2.

(3) Laminate strength (peeling strength)
Polyester urethane adhesive (trade name: Takelac A-969, Takenate A-) was subjected to dry lamination processing on the coated surface side (gas barrier film side) of the gas barrier film obtained in Examples 1 to 13 and Comparative Examples 1 to 7. 5. After laminating an unstretched polypropylene film (trade name: CPP GLC, manufactured by Mitsui Chemicals Tohcello Co., Ltd.) with a thickness of 30 μm via Mitsui Chemicals Co., Ltd.), it is cured at 50 ° C. for 48 hours to obtain a laminated film. rice field. This laminated film is cut into strips with a width of 15 mm, and the gas barrier film is peeled from the unstretched polypropylene film by 90 ° at a speed of 300 mm / min using a tensile tester Tensilon to increase the laminated strength (N / 15 mm). It was measured. The evaluation results are shown in Tables 1 and 2.

As shown in Tables 1 and 2, the gas barrier films of Examples 1 to 13 showed good oxygen barrier properties of 70 cm ³ / (m ² · day · MPa) or less at 30 ° C. and 70% RH. Further, the gas barrier films of Examples 1 to 13 showed a high peel strength of 1.0 N / 15 mm or more. Further, the water-based coating agents of Examples 1 to 13 had a viscosity of 70 mPa · s or less even after one month had passed, and there was no problem in coatability.

Further, in the gas barrier films of Examples 10 to 13, the water-based coating agent contains a vinyl alcohol / vinylamine copolymer (A), an inorganic layered mineral (B), and polyvinyl alcohol (C) as main constituents, and Since it was within the predetermined compounding ratio, it had an oxygen barrier property of 30 cm ³ / (m ² · day · MPa) or less at 30 ° C. and 70% RH, and a peel strength of 1.5 N / 15 mm or more. Therefore, it was found that the gas barrier films of Examples 10 to 13 had an excellent balance between oxygen barrier properties and peel strength.

On the other hand, in the gas barrier films of Comparative Examples 1 to 6, the water-based coating agent does not contain any of the vinyl alcohol-vinylamine copolymer (A) and the inorganic layered mineral (B), or the compounding ratio is high. It was out of the prescribed range. Therefore, the water-based coating agents of Comparative Examples 2 and 5 have high viscosities and cannot be coated, and the gas barrier films of Comparative Examples 1, 3 and 6 have inferior oxygen barrier properties at 30 ° C. and 70% RH, and Comparative Example 4 The gas barrier film has a problem of low peel strength. In the gas barrier film of Comparative Example 7, since the water-based coating agent contained a cross-linking agent, the viscosity increased sharply after one month and the pot life was short.

The water-based coating agent of the present invention and the gas barrier film using the water-based coating agent have a long pot life, excellent gas barrier properties even in a high humidity atmosphere, and have sufficient adhesion strength and film aggregation as a packaging material. Has strength. Therefore, the water-based coating agent of the present invention and the gas barrier film using the same are useful as packaging materials.

Further, the gas barrier film of the present invention can be used as a packaging material for, for example, dried foods, confectionery, bread, delicacies and other foods that dislike moisture and oxygen, and disposable cairo, tablets / powdered medicines or poultices / patches. It is useful. Further, the gas barrier film of the present invention can be used in the packaging field where high gas barrier properties and transparency capable of recognizing the contents are required.

Claims (4)

A gas barrier film comprising a base material and a gas barrier film laminated on at least one surface of the base material.
The gas barrier film contains a vinyl alcohol-vinylamine copolymer (A) and an inorganic layered mineral (B).
The content of the inorganic layered mineral (B) contained in the gas barrier membrane is 5% by mass or more, and the content is 5% by mass or more.
The value obtained by dividing the mass of the vinyl alcohol-vinyl amine copolymer (A) by the mass of the inorganic layered mineral (B) is 2/3 or more .
A gas barrier film, characterized in that the inorganic layered mineral (B) contains water-swellable synthetic mica . The gas barrier film according to claim 1, wherein the content of the inorganic layered mineral (B) contained in the gas barrier film is 8% by mass or more and 30% by mass or less. The gas barrier film according to claim 1 or 2, wherein the gas barrier film further contains polyvinyl alcohol (C). A water-based coating agent containing a vinyl alcohol-vinyl amine copolymer (A) and an inorganic layered mineral (B).
The content of the inorganic layered mineral (B) in the total solid content is 5% by mass or more.
The value obtained by dividing the mass of the vinyl alcohol-vinyl amine copolymer (A) by the mass of the inorganic layered mineral (B) is 2/3 or more .
A water-based coating agent, wherein the inorganic layered mineral (B) contains a water-swellable synthetic mica .