JP2021020398A - Barrier packaging material - Google Patents

Abstract

To provide a barrier packaging material having a heat seal layer having good film forming properties and excellent heat-sealing properties.SOLUTION: There is provided a barrier packaging material obtained by laminating a water vapor barrier layer, a gas barrier layer and a heat seal layer in this order at least on one surface of a paper base material, wherein the heat seal layer contains an olefin-unsaturated carboxylic acid-based copolymer and a partial saponification type ethylene-modified polyvinyl alcohol, the content of the partial saponification type ethylene-modified polyvinyl alcohol in the heat seal layer is 2 mass% or more and 12 mass% or less, the saponification degree of the partial saponification type ethylene-modified polyvinyl alcohol is 86 mol% or more and 96 mol% or less and the coating amount of the heat seal layer is 3 g/m2 or more and 7 g/m2 or less.SELECTED DRAWING: None

Description

The present invention relates to a barrier packaging material.

Packaging materials that have water vapor barrier properties and gas barrier properties (particularly oxygen barrier properties) added to the paper base material have been conventionally used in packaging foods, medical products, electronic parts, etc. in order to prevent deterioration of the quality of the contents. Has been done.

As a method of imparting water vapor barrier property or gas barrier property to a paper base material, a method of laminating a synthetic resin film or a metal foil having excellent gas barrier property using paper as a support is common. However, it is difficult to recycle paper, synthetic resin, etc. after use of a material in which a synthetic resin film or the like is laminated on a paper base material, which poses an environmental problem.
Therefore, the development of a gas barrier material using paper as a base material has been promoted without using a synthetic resin film or the like. For example, Patent Documents 1 and 2 disclose a paper barrier material in which a water vapor barrier layer and a gas barrier layer are provided in this order on a paper base material.

Japanese Patent No. 6234654 Japanese Patent No. 5331265

When a paper barrier material such as Patent Documents 1 and 2 is used for a packaging body, it is necessary to provide a heat seal layer, but the heat seal layer is provided on the material coated with the water vapor barrier layer and the gas barrier layer. When coated, repelling is likely to occur, and cracks are generated in the coating film after formation, so that it is difficult to provide a uniform heat seal layer.
An object of the present invention is to provide a barrier packaging material having a heat-sealing layer having good coating film-forming property and excellent heat-sealing property.

As a result of diligent studies, the present inventors have found that in a barrier packaging material in which a water vapor barrier layer, a gas barrier layer and a heat seal layer are laminated in this order on a paper substrate, the heat seal layer is a-acrylic acid copolymer or the like. It has been found that the above-mentioned problems can be solved by containing a specific amount of partially saponified ethylene-modified polyvinyl alcohol having a specific degree of saponification together with an olefin-unsaturated carboxylic acid-based copolymer.
That is, the present invention relates to the following <1> to <5>.
<1> A barrier packaging material in which a water vapor barrier layer, a gas barrier layer, and a heat seal layer are laminated in this order on at least one surface of a paper base material, and the heat seal layer is an olefin-unsaturated carboxylic acid-based common weight. The partially saponified ethylene-modified polyvinyl alcohol is contained, and the content of the partially saponified ethylene-modified polyvinyl alcohol in the heat seal layer is 2% by mass or more and 12% by mass or less, and the partially saponified ethylene is contained. A barrier packaging material in which the degree of saponification of the modified polyvinyl alcohol is 86 mol% or more and 96 mol% or less, and the coating amount of the heat seal layer is 3 g / m ² or more and 7 g / m ² or less.
<2> The barrier packaging material according to <1>, wherein the viscosity of the partially saponified ethylene-modified polyvinyl alcohol measured by a Brookfield viscometer of a 4% aqueous solution at 20 ° C. is 3 mPa · s or more and 50 mPa · s or less. ..
<3> The barrier packaging material according to <1> or <2>, wherein the gas barrier layer contains at least one of polyvinyl alcohol and ethylene-modified polyvinyl alcohol.
<4> The barrier packaging material according to any one of <1> to <3>, wherein the water vapor barrier layer contains an inorganic compound having an aspect ratio of 50 or more and an olefin-unsaturated carboxylic acid-based copolymer.
<5> A step of applying a water-based composition for a heat-seal layer to a laminate provided with a water vapor barrier layer and a gas barrier layer on at least one surface of a paper base material, and a water-based composition for the coated heat-seal layer. The product is dried to obtain a barrier packaging material in which a paper base material, a water vapor barrier layer, a gas barrier layer and a heat seal layer are provided in this order, and the aqueous composition for the heat seal layer is olefin-free. It contains a saturated carboxylic acid-based copolymer and a partially saponified ethylene-modified polyvinyl alcohol, and the content of the partially saponified ethylene-modified polyvinyl alcohol in the heat seal layer is 2% by mass or more and 12% by mass or less. The degree of saponification of the partially saponified ethylene-modified polyvinyl alcohol is 86 mol% or more and 96 mol% or less, and the amount of coating of the aqueous composition for the heat seal layer after drying is 3 g / m ² or more and 7 g / m ^2. A method for manufacturing a barrier packaging material, which is coated as follows.

According to the present invention, it is possible to provide a barrier packaging material having a heat-sealing layer having good coating film forming property and excellent heat-sealing property.

[Barrier packaging material]
The barrier packaging material of the present invention is a barrier packaging material in which a water vapor barrier layer, a gas barrier layer, and a heat seal layer are laminated in this order on at least one surface of a paper base material, and the heat seal layer is olefin-unsaturated. It contains a carboxylic acid-based copolymer and a partially saponified ethylene-modified polyvinyl alcohol, and the content of the partially saponified ethylene-modified polyvinyl alcohol in the heat seal layer is 2% by mass or more and 12% by mass or less. The degree of saponification of the partially saponified ethylene-modified polyvinyl alcohol is 86 mol% or more and 96 mol% or less, and the coating amount of the heat seal layer is 3 g / m ² or more and 7 g / m ² or less.
According to the present invention, a barrier packaging material having a heat-sealing layer having good coating film forming property and excellent heat-sealing property can be obtained. In the present invention, "good coating film forming property" means that the occurrence of cissing is suppressed during coating and the occurrence of cracks in the coating film is suppressed after the coating film is formed. Means that.
The barrier packaging material of the present invention is a heat obtained by adding a specific amount of a partially saponified ethylene-modified polyvinyl alcohol having a specific degree of saponification to an olefin-unsaturated carboxylic acid-based copolymer such as an ethylene-acrylic acid copolymer. By using the seal layer, the coatability of the heat seal layer is improved without impairing the heat seal property. Although the detailed mechanism is unknown, it is considered that the above-mentioned specific heat-sealing layer improved the affinity with the gas barrier layer and suppressed the occurrence of repellent and cracks. Further, it is presumed that the coatability could be improved without impairing the heat sealability by setting the addition amount of the partially saponified ethylene-modified polyvinyl alcohol to a specific amount.

The barrier packaging material of the present invention may have a water vapor barrier layer, a gas barrier layer, and a heat seal layer in this order on at least one side of the paper base material, and may further have a resin layer or the like on the other side. It is preferable that the water vapor barrier layer, the gas barrier layer and the heat seal layer are provided on only one side in this order, although it is not particularly limited.
Further, by having the water vapor barrier layer, the gas barrier layer and the heat seal layer on only one side in this order, when the barrier packaging material of the present invention is heat-sealed, a bag-shaped product can be easily produced.
Hereinafter, the paper base material used for the barrier packaging material of the present invention and each layer will be described in detail.

<Paper base material>
The paper base material used for the barrier packaging material of the present invention is preferably paper that is generally used with plant-derived pulp as the main component, and more preferably paper with wood pulp as the main component. .. Further, it is preferable that the paper is mainly composed of pulp which is easily dispersed in water by mechanical dissociation action.
Specific examples include bleached or unbleached kraft paper, high-quality paper, paperboard, liner paper, coated paper, single-gloss paper, glassin paper, graphan paper, etc. Among these, bleached or unbleached kraft paper and high-quality paper. , Single glossy paper is preferable.

The dissociation freeness (drainage degree) measured according to JIS P 8121: 2012 of the paper substrate is preferably 800 mL or less, more preferably 500 mL or less, from the viewpoint of improving the barrier property. Here, the dissociation freeness means the Canadian standard freeness of pulp obtained by dissociating the paper after papermaking in accordance with JIS P 820-1: 2012 and measuring it in accordance with JIS P 8121: 2012. That is. As for the method of beating the pulp to adjust the disintegration freeness, a known method can be used.

The size of the paper base material is not particularly limited, but from the viewpoint of improving the barrier property, it is preferable to set the sizing human size according to JIS P 8122: 2004 to 1 second or more. The size of the paper substrate is determined by the type and content of internal sizing agents such as rosin, alkyl ketene dimer, alkenyl succinic anhydride, styrene-acrylic, higher fatty acids, and petroleum resin, and the type of pulp. It can be controlled by smoothing or the like. The content of the internal sizing agent is preferably 3 parts by mass or less with respect to 100 parts by mass of the pulp of the paper base material.

In addition to the internal sizing agent, other known internal additives may be added to the paper substrate. Internal additives include fillers such as titanium dioxide, kaolin, talc, and calcium carbonate, paper strength enhancers, yield improvers, pH adjusters, water drainage improvers, water resistance agents, fabric softeners, antistatic agents, and defoamers. Examples thereof include agents, slime control agents, dyes and pigments.

For paper-based paper making, a known wet paper machine (for example, a long net paper machine, a gap former type paper machine, a circular net type paper machine, a short net type paper machine, etc.) is appropriately selected and used. be able to. The paper layer formed by the paper machine is preferably conveyed by, for example, felt and dried by a dryer. A multi-stage cylinder dryer may be used as a pre-dryer before drying the dryer.

Further, the paper base material obtained as described above may be surface-treated with a calendar to make the thickness and profile uniform. As the calendar processing, a known calendar processing machine can be appropriately selected and used.

The basis weight of the paper substrate is preferably 20 to 500 g / ^{m 2,} more preferably 20 to 400 g / ^{m 2,} more preferably 20 to 200 g / ^{m 2,} even more preferably from 30 to 100 g / ^{m 2} ..
The paper substrate, from the viewpoint of moldability, it is preferable that a density of ^{0.5~1.2g / cm 3, 0.6~1.0g / cm} 3 is more preferable.

<Water vapor barrier layer>
The water vapor barrier layer is a layer having a function of blocking the permeation of water vapor, and preferably contains a water-suspendable polymer, a layered inorganic compound, and a cationic resin.
[Layered inorganic compound]
The form of the layered inorganic compound is preferably flat, and when a mixed solution of the layered inorganic compound and a water-suspendable polymer as a binder is prepared and coated on a paper substrate, a water vapor barrier layer is formed. It is formed.
In the water vapor barrier layer, the flat layered inorganic compounds are arranged in a state of being laminated substantially parallel to the plane (surface) of the paper base material. Then, in the plane direction of the paper base material, the area of the region where the layered inorganic compound does not exist becomes small, so that the permeation of water vapor is suppressed. Further, in the thickness direction of the paper substrate, the flat layered inorganic compounds exist in a state of being arranged parallel to the paper substrate, so that the water vapor in the water vapor barrier layer permeates while bypassing the layered inorganic compounds. Therefore, the permeation of water vapor is suppressed. As a result, the water vapor barrier layer can exhibit excellent water vapor barrier properties.

The thickness (average thickness) of the layered inorganic compound is preferably 300 nm or less, more preferably 200 nm or less, still more preferably 120 nm or less. When the average thickness of the layered inorganic compound is small, the number of laminated layered inorganic compounds in the water vapor barrier layer is large, so that high water vapor barrier property can be exhibited. Here, the thickness of the layered inorganic compound in the state of being contained in the water vapor barrier layer is obtained as follows.
First, a magnified photograph of the vertical cross section of the water vapor barrier layer is taken using an electron microscope. At this time, the magnification is such that about 20 to 30 layered inorganic compounds are contained in the screen. Next, the thickness of each layered inorganic compound in the screen is measured. Then, the average value of the obtained thickness is calculated and used as the thickness (average thickness) of the layered inorganic compound.

The length (average length) of the layered inorganic compound is preferably 1 μm to 100 μm. When the length is 1 μm or more, the layered inorganic compounds are likely to be arranged parallel to the paper substrate. Further, when the length is 100 μm or less, there is little concern that a part of the layered inorganic compound protrudes from the water vapor barrier layer. Here, the length of the layered inorganic compound in the state of being contained in the water vapor barrier layer is obtained as follows.
First, a magnified photograph of the vertical cross section of the water vapor barrier layer is taken using an electron microscope. At this time, the magnification is such that about 20 to 30 layered inorganic compounds are contained in the screen. Next, the length of each layered inorganic compound in the screen is measured. Then, the average value of the obtained lengths is calculated and used as the length of the layered inorganic compound. The length of the layered inorganic compound may be described by the expression of particle size.

The aspect ratio of the layered inorganic compound is preferably 50 or more. When the aspect ratio is 50 or more, it is possible to achieve a predetermined water vapor barrier performance. The aspect ratio of the layered inorganic compound is more preferably 100 or more, still more preferably 300 or more, and particularly preferably 500 or more. The larger the aspect ratio, the more the permeation of water vapor is suppressed and the water vapor barrier property is improved. Further, the larger the aspect ratio, the smaller the amount of the layered inorganic compound added. The upper limit of the aspect ratio is not particularly limited, and is preferably about 10,000 or less from the viewpoint of the viscosity of the coating liquid. Here, the aspect ratio is a value obtained by taking a magnified photograph of the cross section of the water vapor barrier layer using an electron microscope and dividing the average length of the layered inorganic compound obtained by the above method by the average thickness. is there.

Specific examples of layered inorganic compounds include mica such as mica and brittle mica, synthetic mica, bentonite, kaolinite (kaolin mineral), pyrophyllite, talc, smectite, vermiculite, chlorite, septe chlorite, and serpentine. , Stilp nomelene, montmorillonite, etc.
Among the layered inorganic compounds, at least one selected from mica, bentonite, kaolin and talc is particularly preferable from the viewpoint of improving the barrier property. As mica, synthetic mica, muscovite (mascobite), silk mica (serisite), gold mica (frocopite), black mica (biotight), fluorine gold mica (artificial mica), red mica, soda mica, vanajin mica, Elite, chimmica, paragonite, brittle mica, etc. Moreover, as a bentonite, montmorillonite can be mentioned. Kaolin is a clay made by weathering rocks including feldspar, and its main component is kaolinite. Talc is a mineral consisting of magnesium hydroxide and silicate, also called talc.

The content of the layered inorganic compound is preferably 80% by mass or less, more preferably 70% by mass or less, based on the total solid content of the water vapor barrier layer. On the other hand, the content of the layered inorganic compound is preferably 1% by mass or more, more preferably 2% by mass or more. By increasing the aspect ratio and decreasing the thickness of the layered inorganic compound, the content of the layered inorganic compound can be reduced, and the layered inorganic compound can be suppressed from falling off from the water vapor barrier layer.

The content of the layered inorganic compound is preferably 0.1 to 800 parts by mass, more preferably 1 to 400 parts by mass, still more preferably 1 part by mass, based on 100 parts by mass of the water-suspending polymer (binder) of the water vapor barrier layer. It is 1 to 250 parts by mass. When the content of the layered inorganic compound is 0.1 part by mass or more with respect to 100 parts by mass of the water-suspendable polymer (binder) of the water vapor barrier layer, the water vapor barrier property is likely to be exhibited. Further, when the content of the layered inorganic compound is 800 parts by mass or less with respect to 100 parts by mass of the water-suspendable polymer (binder) of the water vapor barrier layer, it is difficult for a part of the layered inorganic compound to be exposed from the layer surface. Therefore, the water vapor barrier property is less likely to decrease. Further, when the content of the layered inorganic compound is 800 parts by mass or less with respect to 100 parts by mass of the water-suspending polymer of the water vapor barrier layer, the coatability of the gas barrier layer is improved and a uniform gas barrier layer is formed. As a result, the gas barrier property is also good.

[Water-suspendable polymer]
A water-suspendable polymer is a polymer that can be suspended in water, and it is easy to prepare a coating solution using water as a dispersion medium when forming a coating film. .. Since the water-suspendable polymer functions as a binder in the formation of the coating film, a coating film containing a layered inorganic compound or the like can be formed on the paper substrate. The polymer serving as the skeleton of the water-suspendable polymer may contain at least one of an olefin-unsaturated carboxylic acid-based copolymer, a styrene-butadiene-based copolymer, an acrylic resin and a biodegradable resin. preferable.

≪Olefin-unsaturated carboxylic acid copolymer≫
An olefin-unsaturated carboxylic acid-based copolymer, which is a typical water-suspendable polymer, will be described below as an example. Examples of the unsaturated carboxylic acid-based monomer constituting the olefin-unsaturated carboxylic acid-based copolymer include acrylic acid, methacrylic acid, crotonic acid, silicic acid, itaconic acid, fumaric acid, maleic acid, and butentricarboxylic acid. Unsaturated polycarboxylic acid alkyl esters with at least one carboxy group, such as unsaturated carboxylic acids, itaconic acid monoethyl esters, fumaric acid monobutyl esters and maleic acid monobutyl esters, acrylamide propanesulfonic acids, acrylic acid sulfos. Examples thereof include unsaturated sulfonic acid monomers such as ethyl sodium salt and sulfopropyl sodium methacrylate salt, or salts thereof. The unsaturated carboxylic acid-based monomer constituting the olefin-unsaturated carboxylic acid-based copolymer may be one kind or a combination of two or more kinds.
As the olefin monomer, ethylene such as ethylene, propylene and butylene and α-olefin are preferable, and among these, ethylene is more preferable.

The olefin-unsaturated carboxylic acid-based copolymer is preferably a copolymer obtained by emulsion polymerization of the olefin monomer and the above-mentioned unsaturated carboxylic acid-based monomer. As the unsaturated carboxylic acid-based monomer, acrylic acid, methacrylic acid and the like are suitable. Examples of the olefin-unsaturated carboxylic acid-based copolymer include ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-methyl methacrylate copolymer, and ethylene-acrylic. It is preferably at least one of an ethyl acid copolymer, an ethylene-ethyl methacrylate copolymer, an ethylene-butyl acrylate copolymer and an ethylene-butyl methacrylate copolymer. The copolymer may be copolymerized with a small amount of a monomer composed of an olefin and another compound copolymerizable with the unsaturated carboxylic acid-based monomer.

Among these, an ethylene-acrylic acid copolymer is preferable as the olefin-unsaturated carboxylic acid-based copolymer.
Specific examples of the olefin-unsaturated carboxylic acid-based copolymer include, for example, an aqueous dispersion of an ammonium salt of an ethylene-acrylic acid copolymer, Zyxen® AC or the like (copolymerization ratio of acrylic acid 20 mol%, Sumitomo). It is commercially available as Seika Co., Ltd., and can be easily obtained and used.

The olefin-unsaturated carboxylic acid-based copolymer preferably has an unsaturated carboxylic acid-based monomer unit content of 1 to 50 mol%. When the content of the acrylic monomer unit is in this range, the dispersibility of the layered inorganic compound is excellent. The content of the unsaturated carboxylic acid-based monomer unit in the olefin-unsaturated carboxylic acid-based copolymer is more preferably 10 to 30 mol%.

The weight average molecular weight of the olefin-unsaturated carboxylic acid-based copolymer is preferably 10,000 to 10 million, more preferably 100,000 to 5 million, from the viewpoint of the viscosity of the coating liquid and the strength of the coating film.

The content ratio of the olefin-unsaturated carboxylic acid-based copolymer is not particularly limited, but is preferably 20% by mass or more, more preferably 30% by mass or more, based on the total solid content of the water vapor barrier layer.

≪Biodegradable resin≫
Specific examples of the biodegradable resin are not particularly limited, and for example, polylactic acid (PLA), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), 3-hydroxy Examples thereof include a butanoic acid / 3-hydroxyhexanoic acid copolymer (PHBH). Packaging materials using a paper base material have the advantage of reducing the environmental load compared to packaging materials using a thermoplastic resin, but they are biodegradable as water-suspendable polymers in the water vapor barrier layer. By using the resin, the environmental load can be further reduced.

The water-suspendable polymer (binder) in the water vapor barrier layer is preferably anionic. Since the binder is anionic, the water vapor barrier property is further improved. As will be described later, the planar portion of the layered inorganic compound is anionic, but when the cationic resin described later is adsorbed, the surface becomes cationic. Therefore, the affinity with the anionic binder is enhanced.

The water vapor barrier layer preferably contains a layered inorganic compound and an olefin-unsaturated carboxylic acid-based copolymer, and contains a layered inorganic compound having an aspect ratio of 50 or more and an ethylene-acrylic acid copolymer. Is more preferable.

[Cationic resin]
In the present inventor, it is preferable to add a cationic resin to the water vapor barrier layer containing the layered inorganic compound. By adding the cationic resin, the water vapor barrier property is greatly improved.
The reason why the water vapor barrier property is greatly improved by adding the cationic resin is considered as follows. It is known that the layered inorganic compound has a so-called card house structure in which the layered inorganic compounds are three-dimensionally aggregated with each other because the flat portion in the flat form is easily charged anionic and the edge portion is cationically charged. There is. Due to this card house structure, the viscosity of the aqueous dispersion of the layered inorganic compound becomes very high. On the other hand, since the card house structure is easily broken when a force is applied by stirring or the like, the aqueous dispersion of the layered inorganic compound exhibits thixotropy.
It is considered that when an appropriate cationic resin is added to the aqueous dispersion of the layered inorganic compound, the cardhouse structure is destroyed by adsorbing the cationic resin on the anionic flat portion of the layered inorganic compound. As a result, it is presumed that the three-dimensional aggregation of the layered inorganic compound is suppressed, the flat layered inorganic compound is easily laminated in parallel with the plane of the paper substrate, and the water vapor barrier property is improved. There is.

Specific examples of the cationic resin include polyamine resins, cation-modified polyamide resins (for example, amine-modified polyamide resins), polyamide epichlorohydrin resins, polyethyleneimine resins, polyalkylene polyamine resins, polyamide compounds, polyamideamine-epihalohydrins or formaldehydes. Condensation reaction product, polyamine-epihalohydrin or formaldehyde condensation reaction product, polyamide polyurea-epihalohydrin or formaldehyde condensation reaction product, polyamine polyurea-epihalohydrin or formaldehyde condensation reaction product, polyamideamine polyurea-epihalohydrin or formaldehyde condensation reaction product Examples thereof include products, polyamide polyurea compounds, polyamine polyurea compounds, polyamideamine polyurea compounds and polyamideamine compounds, polyvinylpyridines, amino-modified acrylamide compounds, polyvinylamine resins, and polydialyldimethylammonium chlorides.
Among these, at least one selected from polyamine resin, cation-modified polyamide resin, polyamide epichlorohydrin resin and polyethyleneimine resin is preferable.

The surface charge of the cationic resin is preferably 0.1 to 10 meq / g, more preferably 0.1 to 5.0 meq / g. When the surface charge of the cationic resin is within the above range, the card house structure can be destroyed, and the anionic binder (anionic water-suspending polymer) described above can coexist appropriately. ..
The surface charge of the cationic resin is measured by the method described below. First, the polymer as a sample is dissolved in water to obtain a solution having a polymer concentration of 1 ppm. To the solution, 0.001N sodium polyethylene sulfonate is added dropwise using a charge analyzer Mutek PCD-04 (manufactured by BTG), and the amount of charge is measured.

The content of the cationic resin in the water vapor barrier layer may be appropriately determined according to the types of the layered inorganic compound and the water-suspendable polymer used in the water vapor barrier layer, but from the viewpoint of improving the barrier property, it is layered. With respect to 100 parts by mass of the inorganic compound, it is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, further preferably 1.5 parts by mass or more, and preferably 300 parts by mass or less, more preferably 300 parts by mass or less. It is 200 parts by mass or less, more preferably 100 parts by mass or less, and particularly preferably 30 parts by mass or less.

The content of the cationic resin is preferably 0.1 to 20 parts by mass and 1 to 15 parts by mass with respect to 100 parts by mass of the water-suspending polymer (binder) of the water vapor barrier layer. Is more preferable, and 3 to 10 parts by mass is further preferable.

In addition to the water-suspendable polymer, the layered inorganic compound, and the cationic resin, the water vapor barrier layer includes a dispersant, a surfactant, a defoaming agent, a wetting agent, a dye, a color adjusting agent, and an increase as necessary. It is possible to add a thickener or the like.

The thickness of the water vapor barrier layer is preferably 1 to 30 μm, more preferably 3 to 20 μm. Further, the coating amount of the water vapor barrier layer as a solid content, is preferably from 1 to 30 g / ^{m 2,} more preferably 3 to 20 g / ^{m 2.}

<Gas barrier layer>
The gas barrier layer is a layer having a function of mainly blocking the permeation of oxygen gas, that is, the gas barrier layer is preferably an oxygen barrier layer. The gas barrier layer preferably contains a water-soluble polymer.

[Water-soluble polymer]
Examples of the water-soluble polymer include polyvinyl alcohol, modified polyvinyl alcohol, starch and its derivatives, cellulose derivatives, polyvinylpyrrolidone, urethane resins, polyacrylic acid and salts thereof, casein, polyethyleneimine and the like.
Among these, completely saponified or partially saponified polyvinyl alcohol or modified polyvinyl alcohol is preferable because it has more excellent gas barrier properties. Examples of the modified polyvinyl alcohol include ethylene-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, and diacetone-modified polyvinyl alcohol.
Further, from the viewpoint of affinity with the heat seal layer, it is preferable to contain at least one of polyvinyl alcohol and ethylene-modified polyvinyl alcohol. The polyvinyl alcohol and ethylene-modified polyvinyl alcohol are preferably fully saponified polyvinyl alcohol and fully saponified ethylene-modified polyvinyl alcohol.
In polyvinyl alcohol and ethylene-modified polyvinyl alcohol, complete saponification means that the degree of saponification is more than 96%.

The content of the water-soluble polymer is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, based on the total solid content of the gas barrier layer.

The gas barrier layer may contain a nitrogen-containing compound typified by urethane resin, polyalkyleneimine, or the like from the viewpoint of further improving the adhesive strength with the water vapor barrier layer and the heat seal layer and further improving the gas barrier property. Good.
Examples of the nitrogen-containing compound include polyethylene imine, polypropylene imine, an ethylene imine adduct of ethylene urea, an imine compound such as an alkyl-modified product, an alkenyl-modified product, and a benzyl-modified product thereof, or polyethylene polyamine, ethylene diamine, diethylene triamine, and polyvinyl. It has an organic amine compound such as amine, other polyamine polyamide compound, polyalkyleneimine such as alkyl or cyclopentyl-modified polyethyleneimine, other quaternary nitrogen-containing acrylic polymer, (cationically modified) polyurethane, methylolated melamine, and amine carboxylic acid base. Examples include compounds.

In particular, in the present invention, it is preferable to use polyalkyleneimine among the nitrogen-containing compounds. Since the polyalkyleneimine is a so-called cationic nitrogen-containing compound containing a nitrogen atom in the main chain skeleton or the branched chain skeleton of the molecule, it is contained in the water-suspendable polymer in the water vapor barrier layer. While strongly bonded to the anionic polar group, it also strongly bonds to the anionic polar group of the olefin-unsaturated carboxylic acid-based copolymer such as the ethylene-acrylic acid copolymer provided on the heat-sealed layer. Since they are combined, it is possible to obtain a barrier packaging material having very excellent adhesion between the layers.

The content of the nitrogen-containing compound is preferably 0.01 to 10% by mass, more preferably 0.1 to 3% by mass, still more preferably, from the viewpoint of improving the gas barrier property and the adhesiveness in the total solid content of the gas barrier layer. Is 0.3 to 1% by mass.

Similar to the water vapor barrier layer, the gas barrier layer may contain the above-mentioned layered inorganic compound. When the layered inorganic compound is contained in the gas barrier layer, the content of the layered inorganic compound is not particularly limited, but is preferably about 1 to 20 parts by mass, preferably about 5 to 15 parts by mass with respect to 100 parts by mass of the water-soluble polymer of the gas barrier layer. Parts by mass are more preferred. The layered inorganic compound is preferably at least one selected from mica, bentonite, kaolin and talc from the viewpoint of improving the barrier property. The layered inorganic compound contained in the gas barrier layer may be of the same type as the layered inorganic compound contained in the water vapor barrier layer, or may be of a different type.

In addition to the water-soluble polymer, nitrogen-containing compound, and layered inorganic compound, the gas barrier layer includes pigments, dispersants, surfactants, defoamers, wetting agents, dyes, color modifiers, and thickeners as appropriate. It is possible to add agents and the like.

The thickness of the gas barrier layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm. The coating amount of the gas barrier layer is preferably 0.1 to 10 g / m ² and more preferably 0.5 to 5 g / m ² as the solid content.

<Heat seal layer>
The heat seal layer is a layer formed on the gas barrier layer, and is a layer that melts and adheres by heating. The heat-sealed layer contains an olefin-unsaturated carboxylic acid-based copolymer and a partially saponified ethylene-modified polyvinyl alcohol.
A heat seal layer may be provided on the surface opposite to the surface on which the water vapor barrier layer of the paper base material is provided.
≪Olefin-unsaturated carboxylic acid copolymer≫
The heat-sealed layer contains an olefin-unsaturated carboxylic acid-based copolymer. Examples of the unsaturated carboxylic acid-based monomer constituting the olefin-unsaturated carboxylic acid-based copolymer include acrylic acid, methacrylic acid, crotonic acid, silicic acid, itaconic acid, fumaric acid, maleic acid, and butentricarboxylic acid. Unsaturated polycarboxylic acid alkyl esters with at least one carboxy group, such as unsaturated carboxylic acids, itaconic acid monoethyl esters, fumaric acid monobutyl esters and maleic acid monobutyl esters, acrylamide propanesulfonic acids, acrylic acid sulfos. Examples thereof include unsaturated sulfonic acid monomers such as ethyl sodium salt and sulfopropyl sodium methacrylate salt, or salts thereof. The unsaturated carboxylic acid-based monomer constituting the olefin-unsaturated carboxylic acid-based copolymer may be one kind or a combination of two or more kinds.
As the olefin monomer, ethylene such as ethylene, propylene and butylene and α-olefin are preferable, and among these, ethylene is more preferable.

The olefin-unsaturated carboxylic acid-based copolymer is preferably a copolymer obtained by emulsion polymerization of the olefin monomer and the above-mentioned unsaturated carboxylic acid-based monomer. As the unsaturated carboxylic acid-based monomer, acrylic acid, methacrylic acid and the like are suitable. Examples of the olefin-unsaturated carboxylic acid-based copolymer include ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-methyl methacrylate copolymer, and ethylene-acrylic. It is preferably at least one of an ethyl acid copolymer, an ethylene-ethyl methacrylate copolymer, an ethylene-butyl acrylate copolymer and an ethylene-butyl methacrylate copolymer. The copolymer may be copolymerized with a small amount of a monomer composed of an olefin and another compound copolymerizable with the unsaturated carboxylic acid-based monomer.

Among these, an ethylene-acrylic acid copolymer is preferable as the olefin-unsaturated carboxylic acid-based copolymer.
The content of the constitutive unit derived from the unsaturated carboxylic acid monomer in the olefin-unsaturated carboxylic acid copolymer and the structural unit derived from acrylic acid in the ethylene-acrylic acid copolymer is excellent heat seal. From the viewpoint of obtaining excellent coating property with respect to the property and the gas barrier layer which is the lower layer, it is preferably 1 mol% or more, more preferably 3 mol% or more, still more preferably 10 mol% or more, still more preferably 15 mol% or more. Yes, and preferably 60 mol% or less, more preferably 40 mol% or less, still more preferably 30 mol% or less, still more preferably 25 mol% or less. When the content of the constituent unit derived from the unsaturated carboxylic acid-based monomer and acrylic acid is within the above range, the melt viscosity becomes 60 to 120 ° C., and excellent heat-sealing property can be obtained.

The weight average molecular weight of the olefin-unsaturated carboxylic acid-based copolymer is preferably 10,000 to 10 million, more preferably 100,000 to 5 million, from the viewpoint of the viscosity of the coating liquid and the strength of the coating film.

Specific examples of the olefin-unsaturated carboxylic acid-based copolymer include, for example, an aqueous dispersion of an ammonium salt of an ethylene-acrylic acid copolymer, Zyxen® AC or the like (copolymerization ratio of acrylic acid 20 mol%, Sumitomo). It is commercially available as Seika Co., Ltd., and can be easily obtained and used.

The content ratio of the olefin-unsaturated carboxylic acid-based copolymer in the heat-sealing layer is 98% by mass or less, preferably 97% by mass, based on the solid content of the heat-sealing layer from the viewpoint of coating film forming property and heat-sealing property. % Or less, more preferably 96% by mass or less, and preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 88% by mass or more, still more preferably 89% by mass or more.

≪Partially saponified ethylene-modified polyvinyl alcohol≫
In the present invention, the heat seal layer contains a partially saponified ethylene-modified polyvinyl alcohol.
The partially saponified ethylene-modified polyvinyl alcohol is obtained by partially saponifying an ethylene-vinyl ester polymer obtained by copolymerizing ethylene and a vinyl ester-based monomer, and using a part of the vinyl ester units as vinyl alcohol units. Is.
Examples of the vinyl ester-based monomer include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl versatic acid and the like, and vinyl acetate is preferable among them.

The degree of saponification of the partially saponified ethylene-modified polyvinyl alcohol is 86 mol% or more, preferably 88 mol% or more, more preferably 90 mol% or more, still more preferably 92, from the viewpoint of heat sealability and coating film forming property. It is mol% or more and 96 mol% or less, preferably 95 mol% or less, more preferably 94 mol% or less.

The degree of ethylene modification of the partially saponified ethylene-modified polyvinyl alcohol is preferably 1 mol% or more, and preferably 50 mol% or less, from the viewpoint of solubility in water, heat sealability and coating film forming property. It is more preferably 35 mol% or less, still more preferably 20 mol% or less, still more preferably 15 mol% or less, and particularly preferably 10 mol% or less.
The degree of ethylene modification is the ethylene in the ethylene-vinyl ester polymer obtained by copolymerizing ethylene and the vinyl ester monomer or the ethylene in the partially saponified ethylene-modified polyvinyl alcohol obtained by partially saponifying the polymer. It is the content (mol%) of the constituent unit from which it is derived, and its numerical value is obtained from the measurement by the nuclear magnetic resonance method.

When copolymerizing ethylene and a vinyl ester-based monomer in order to obtain a partially saponified ethylene-modified polyvinyl alcohol, if necessary, other monomers copolymerizable as long as the effects of the present invention are not impaired. May be copolymerized. The content of the other monomers is preferably 15 mol% or less, more preferably 10 mol% or less, still more preferably 5 mol% or less, and may not be contained in the total monomers.
Examples of other copolymerizable monomers include olefins having 3 to 30 carbon atoms such as propylene, 1-butene, and isobutene; (meth) acrylic acid and salts thereof; methyl (meth) acrylate, and (meth) acrylic. Ethyl acid acid, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2 (meth) acrylate -(Meta) acrylate amides such as ethylhexyl, dodecyl (meth) acrylate, octadecyl (meth) acrylate; (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N- (Meta) acrylamide derivatives such as dimethyl (meth) acrylamide, (meth) acrylamide propanesulfonic acid and its salts, (meth) acrylamide propyldimethylamine and its salts, N-methylol (meth) acrylamide; N-vinylformamide, N- N-vinylamides such as vinylacetamide and N-vinylpyrrolidone; vinyl ethers such as methylvinyl ether, ethylvinyl ether, n-propylvinyl ether, isopropylvinyl ether, n-butylvinyl ether, isobutylvinyl ether, t-butylvinyl ether, dodecylvinyl ether and stearylvinyl ether. Nitriles such as acrylonitrile and methacrylnitrile; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; maleic acid and its salts or esters thereof; Itaconic acid and its salts or esters thereof; vinylsilyl compounds such as vinyltrimethoxysilane; N-vinylamides such as isopropenyl acetate, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone and the like.

As the partially saponified ethylene-modified polyvinyl alcohol, a commercially available product may be used. For example, Exevar (registered trademark) (Kuraray Co., Ltd.) is exemplified, and an appropriate selection is made according to the desired degree of saponification, viscosity and the like. You can use it.

The viscosity of the partially saponified ethylene-modified polyvinyl alcohol measured by a Brookfield viscometer of a 4% aqueous solution at 20 ° C. is preferably 3 mPa · s or more, more preferably 5 mPa · s or more, from the viewpoint of coating film forming property. It is more preferably 10 mPa · s or more, and preferably 50 mPa · s or less, more preferably 40 mPa · s or less, still more preferably 30 mPa · s or less.

The content of the partially saponified ethylene-modified polyvinyl alcohol in the heat seal layer is 2% by mass or more, preferably 3% by mass or more, more preferably 4% by mass or more, and 12% by mass or less in terms of solid content. It is preferably 10% by mass or less.
When the content of the partially saponified ethylene-modified polyvinyl alcohol in the heat seal layer is 2% by mass or more in terms of solid content, the generation of repellent when the heat seal layer is applied on the gas barrier layer is suppressed, and the generation is suppressed. The occurrence of cracks is also suppressed, and the coating film forming property is good.
Further, when the content of the partially saponified ethylene-modified polyvinyl alcohol in the heat-seal layer is 12% by mass or less in terms of solid content, good heat-sealability can be obtained.

The amount of the heat seal layer coated is, in terms of solid content, 3 g / m ² or more, preferably 3.5 g / m ² or more, more preferably 4 g / m ² or more, still more preferably 5 g / m ² or more, and , 7 g / m ² or less, preferably 6.5 g / m ² or less.
When the coating amount of the heat seal layer is 3 g / m ² or more in terms of solid content, excellent heat seal properties can be obtained. Further, when it is 7 g / m ² or less, the coating film forming property is good and the occurrence of cracks in the heat seal layer is suppressed.

The thickness of the heat seal layer is preferably 1 μm or more, more preferably 3 μm or more, and preferably 20 μm or less, more preferably 10 μm or less, in order to obtain sufficient heat seal properties.

[Barrier packaging material]
The barrier packaging material of the present invention has a water vapor barrier layer, a gas barrier layer, and a heat seal layer in this order on at least one side of the paper base material. A protective layer, a heat seal layer, and the like may be provided on the other surface of the paper base material.

The barrier packaging material of the present invention is excellent in water vapor barrier property and gas barrier property.
Regarding the water vapor barrier property, specifically, the water vapor permeability is preferably 20 g / m ² · day or less, and more preferably 10 g / m ² · day or less.
Regarding the gas barrier property, specifically, the oxygen permeability is preferably 1 mL / m ² · day · atm or less, and more preferably 0.5 mL / m ² · day · atm or less.

[Manufacturing method of barrier packaging material]
The barrier packaging material of the present invention has at least three layers on a paper substrate.
The method for forming each layer is not particularly limited, but it is preferably formed by a coating method. Specifically, a water vapor barrier layer coating liquid (water vapor barrier layer paint) is first applied onto a paper substrate, dried to form a water vapor barrier layer, and then a gas barrier layer coating liquid (gas barrier layer paint). ) Is applied and dried to form a gas barrier layer, and further, a heat seal layer coating liquid (heat seal layer paint) is applied and dried to form a heat seal layer.

When forming a plurality of coating layers on the paper substrate, the above method of sequentially forming the coating layers is preferable, but the present invention is not limited to this, and a simultaneous multi-layer coating method is adopted. May be good. The simultaneous multi-layer coating method is a multi-layer coating method in which a plurality of types of coating liquids are separately discharged from a slit-shaped nozzle to form a liquid laminate, which is then coated on a paper substrate. This is a method of forming a working film at the same time.

The coating equipment for applying the coating liquid is not particularly limited, and known equipment may be used. Examples of the coating equipment include a blade coater, a bar coater, an air knife coater, a slit die coater, a gravure coater, a micro gravure coater, and a gate roll coater. In particular, for forming the water vapor barrier layer, a coater such as a blade coater, a bar coater, an air knife coater, or a slit die coater that scrapes the coated surface is preferable because it promotes the orientation of the layered inorganic compound.
The drying equipment for drying the coating layer is not particularly limited, and known equipment can be used. Examples of the drying equipment include a hot air dryer, an infrared dryer, a gas burner, and a hot plate. Further, the drying temperature may be appropriately set in consideration of the drying time and the like.

The solvent of the coating liquid for each layer is not particularly limited, and water or an organic solvent such as ethanol, isopropyl alcohol, methyl ethyl ketone or toluene can be used.
Among these, in the present invention, water is preferable as the dispersion medium of the coating liquid of each layer from the viewpoint of not causing the problem of the volatile organic solvent.
That is, the water vapor barrier layer coating liquid is a water vapor barrier layer water-based composition, and the gas barrier layer coating liquid is a gas barrier layer water-based composition.

The solid content of the coating liquid of each layer is not particularly limited and may be appropriately selected from the viewpoint of coatability and ease of drying, but is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 10. It is 5% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, and further preferably 60% by mass or less.

In the present invention, the barrier packaging material is preferably produced by the following method.
A step of applying the water-based composition for the heat-seal layer to a laminate provided with a water vapor barrier layer and a gas barrier layer on at least one side of the paper base material, and drying the coated water-based composition for the heat-seal layer. Then, a step of obtaining a barrier packaging material in which a paper base material, a water vapor barrier layer, a gas barrier layer and a heat seal layer are provided in this order is provided, and the aqueous composition for the heat seal layer is an olefin-unsaturated carboxylic acid. It contains a system copolymer and a partially saponified ethylene-modified polyvinyl alcohol, and the content of the partially saponified ethylene-modified polyvinyl alcohol in the heat seal layer is 2% by mass or more and 12% by mass or less, and the partial ken The degree of saponification of the modified ethylene-modified polyvinyl alcohol is 86 mol% or more and 96 mol% or less, and the coating amount of the aqueous composition for the heat seal layer after drying is 3 g / m ² or more and 7 g / m ² or less. A method of manufacturing a barrier packaging material that is coated in such a way.

The barrier packaging material of the present embodiment can be suitably used as a packaging material for foods, medical products, electronic parts, etc. by taking advantage of the above-mentioned excellent water vapor barrier property, gas barrier property, and heat sealing property.

The features of the present invention will be described in more detail with reference to Examples and Comparative Examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below. Unless otherwise specified, "parts" and "%" in Examples and Comparative Examples indicate "parts by mass" and "% by mass", respectively.

[Example 1]
<Preparation of water vapor barrier layer paint>
55 parts of Varisurf HX (manufactured by Imeris Minerals, engineered kaolin, solid content 100%, particle size 9.0 μm, aspect ratio 80-100, thickness about 100 nm) and 45 parts of water are mixed using a cowless disperser. , Kaolin aqueous dispersion (concentration 55% by mass) was obtained. Zyxen AC (manufactured by Sumitomo Seika Co., Ltd., ethylene-acrylic acid copolymer ammonium salt, solid content 29%, copolymerization ratio of acrylic acid: 20 mol%, melting point: 80 to 95 ° C.) 113 parts, kaolin aqueous dispersion 120 parts of liquid, violet resin SPI-203 (50) H (manufactured by Taoka Chemical Industry Co., Ltd., cation-modified polyamide resin, solid content 51%, surface charge 0.4 meq / g) 2.6 parts, and solid content concentration Water was added so as to be 40%, and the mixture was stirred to prepare a steam barrier layer coating film (concentration: 40%).

<Preparation of gas (oxygen) barrier layer paint>
Exevar AQ-4104 (manufactured by Kuraray Co., Ltd., ethylene-modified polyvinyl alcohol, solid content 100%, completely saponified type) 99.5 parts dissolved in water, Epomin P-1000 (manufactured by Nippon Catalyst Co., Ltd., polyethyleneimine) , 1.7 parts (solid content concentration 30%) was added, water was further added so that the solid content concentration became 11%, and the mixture was stirred to prepare a gas barrier layer coating material (concentration 11%).

<Preparation of heat seal layer paint>
Zyxen AC (manufactured by Sumitomo Seika Co., Ltd., ethylene-acrylic acid copolymer ammonium salt, solid content 29%, copolymerization ratio of acrylic acid 20 mol%, melting point: 80 to 95 ° C.) 327.6 parts, water in advance Exevar RS-1713 (manufactured by Kuraray Co., Ltd., partially saponified ethylene-modified polyvinyl alcohol, saponification degree 92 to 94 mol%, viscosity (20 ° C., 4% aqueous solution) 15.5 to 21.0 mPa · s , 100% solid content) Water dispersion (concentration 11%) 45.5 parts were mixed, and water was further added so as to have a solid content concentration of 20% and stirred to obtain a heat seal layer coating material (concentration 20%).

<Manufacturing of barrier packaging materials>
The resulting water vapor barrier layer coating, so that the coating amount after drying of the water vapor barrier layer is 12 g / m ^2, bleached kraft paper (basis weight 52 g / m ^2, a thickness of 68 .mu.m, Stockigt sizing degree of 15 seconds , Manufactured with a kraft paper machine, Oken type smoothness 60 seconds), coated on one surface with a Mayer bar, dried in a hot air dryer at 120 ° C. for 1 minute, and steam barrier layer (thickness after drying) : Approximately 7 μm) was formed. Further, after applying the gas barrier layer paint on the water vapor barrier layer with a Mayer bar so that the amount of the gas barrier layer applied after drying is 2.5 g / m ² (thickness after drying: about 2 μm). , 120 ° C. for 1 minute in a hot air dryer to form a gas barrier layer. Further, the heat seal layer paint is applied onto the gas barrier layer with a Mayer bar so that the amount of the heat seal layer applied after drying is 6.0 g / m ² (thickness after drying: about 7 μm). Then, it was dried in a hot air dryer at 120 ° C. for 1 minute to form a heat seal layer, and a barrier packaging material was obtained. The amount of coating was adjusted according to the solid content concentration of the coating liquid and the count of the Mayer bar.

[Example 2]
A barrier packaging material was obtained in the same manner as in Example 1 except that the number of parts of Zyxen AC blended in the heat seal layer paint was changed to 310 parts and the number of parts of Exevar RS-1713 aqueous dispersion was changed to 90.9 parts. ..

[Example 3]
Exevar RS-1713 aqueous dispersion blended in heat seal layer paint, Exevar RS1717 (manufactured by Kuraray Co., Ltd., partially saponified ethylene-modified polyvinyl alcohol, saponification degree 92-94 mol%, viscosity (20 ° C, 4% aqueous solution) ) 23.0 to 30.0 mPa · s, solid content 100%) A barrier packaging material was obtained in the same manner as in Example 1 except that the mixture was changed to an aqueous dispersion (concentration 11%).

[Example 4]
A barrier packaging material was obtained in the same manner as in Example 1 except that the coating amount of the heat seal layer after drying was changed to 4.0 g / m ² .

[Example 5]
Exevar AQ-4104 blended in gas barrier layer paint is Kuraray Poval PVA-28-98 (manufactured by Kuraray Co., Ltd., fully saponified polyvinyl alcohol, saponification degree 98-99 mol%, viscosity (20 ° C, 4% aqueous solution) A barrier packaging material was obtained in the same manner as in Example 1 except that the mixture was changed to 25.0 to 31.0 mPa · s and 100% solid content).

[Comparative Example 1]
A barrier packaging material was obtained in the same manner as in Example 1 except that the composition of the heat seal layer paint was changed to only 345 parts of Zyxen AC.

[Comparative Example 2]
A barrier packaging material was obtained in the same manner as in Example 1 except that the number of parts of Zyxen AC blended in the heat seal layer paint was changed to 341 parts and the number of parts of Exevar RS-1713 aqueous dispersion was changed to 9.1 parts. ..

[Comparative Example 3]
A barrier packaging material was obtained in the same manner as in Example 1 except that the number of parts of Zyxen AC blended in the heat seal layer paint was changed to 293 parts and the number of parts of Exevar RS-1713 aqueous dispersion was changed to 136 parts.

[Comparative Example 4]
Exevar RS-1713 aqueous dispersion mixed with heat seal layer paint is mixed with Exevar RS-2117 (manufactured by Kuraray Co., Ltd.), fully saponified ethylene-modified polyvinyl alcohol, saponification degree 97.5-99 mol%, viscosity (20 ° C). A barrier packaging material was obtained in the same manner as in Example 1 except that the solution was changed to an aqueous dispersion (4% aqueous solution) 25.0 to 30.0 mPa · s, solid content 100%).

[Comparative Example 5]
Exevar RS-1713 aqueous dispersion blended in heat seal layer paint, Exevar RS-4104 (manufactured by Kuraray Co., Ltd., fully saponified ethylene-modified polyvinyl alcohol, saponification degree 98-99 mol%, viscosity (20 ° C, 4) % Aqueous solution) 3.5 to 4.5 mPa · s, solid content 100%) A barrier packaging material was obtained in the same manner as in Example 1 except that the solution was changed to an aqueous dispersion.

[Comparative Example 6]
A barrier packaging material was obtained in the same manner as in Example 1 except that the coating amount of the heat seal layer after drying was changed to 2.0 g / m ² .

[Comparative Example 7]
A barrier packaging material was obtained in the same manner as in Example 1 except that the coating amount of the heat seal layer after drying was changed to 8.0 g / m ² .

[Evaluation]
<Humidity (water vapor permeability)>
Measurement was performed by JIS-Z-0208 (cup method) B method (40 ° C. ± 0.5 ° C., 90% ± 2% RH) with the water vapor barrier layer inside. As the standard for the moisture permeability, if 50g ^/ m 2 · 24h or less, there is a practical as water vapor barrier layer.

<Oxygen permeability>
The measurement was performed at 23 ° C. and 50% RH conditions using an oxygen permeability measuring device (OX-TRAN2 / 20 manufactured by MOCON). Incidentally, as a measure of the oxygen permeability, when 10cc ^/ m 2 · 24h or less, there is a practical as gas barrier layer.

<Evaluation of Hajiki>
After coating the heat seal layer with a Mayer bar, the coated surface was visually observed 2 seconds later and evaluated according to the following criteria. As an evaluation of performance, the case of A was judged to be acceptable.
A: There is no repellency and a uniform surface condition is maintained.
B: A minute repellent is generated.
C: Large repellent is generated on the entire surface.

<Evaluation of cracks>
The coated surface of the obtained barrier packaging material was visually observed and evaluated according to the following criteria. As an evaluation of performance, the case of A was judged to be acceptable.
A: No cracks on the coated surface B: There are minute cracks on a part of the coated surface C: There are cracks on the entire surface of the coated surface

<Evaluation of heat sealability>
A set of barrier packaging materials are stacked so that the heat seal layers face each other, and heat seal is performed using a heat seal tester (manufactured by Tester Sangyo, TP-701-B) at 140 ° C., 2.0 MPa, and 1 second. , Evaluated according to the following criteria. As an evaluation of performance, the case of A or B was judged to be acceptable.
A: Destruction of the base material when peeled by hand B: Destruction of the base material when peeled by hand in most cases, but rarely the base material is destroyed C: Destruction of the base material when peeled by hand Does not occur, but does not peel off easily D: Easy to peel off

The barrier packaging material of the example had better coating film forming property than the barrier packaging material of the comparative example, and the occurrence of cissing and cracking in the heat seal layer was suppressed. Furthermore, the barrier packaging material of the examples showed good heat sealability.
On the other hand, in Comparative Example 1 in which the heat seal layer does not contain the partially saponified ethylene-modified polyvinyl alcohol and Comparative Example 2 in which the heat-sealed layer contains the partially saponified ethylene-modified polyvinyl alcohol but the content is small, the coating film forming property becomes poor. Repellents and cracks occurred. Further, in Comparative Example 3 containing a large amount of partially saponified ethylene-modified polyvinyl alcohol, the heat sealability was poor. Further, in Comparative Examples 4 and 5 using the completely saponified ethylene-modified polyvinyl alcohol, sufficient heat-sealing property could not be obtained. Further, in Comparative Example 5 in which a completely saponified ethylene-modified polyvinyl alcohol having a low viscosity was used, repellent was generated, which was considered to be accompanied by a decrease in affinity with the oxygen barrier layer.
Further, in Comparative Example 6 in which the amount of coating of the heat seal layer was small, sufficient heat sealability could not be obtained. Further, in Comparative Example 7 in which the amount of coating of the heat seal layer was large, cracks were generated in the heat seal layer, and the coating film forming property was not sufficient.

Claims (5)

A barrier packaging material in which a water vapor barrier layer, a gas barrier layer, and a heat seal layer are laminated in this order on at least one side of a paper base material.
The heat-sealed layer contains an olefin-unsaturated carboxylic acid-based copolymer and a partially saponified ethylene-modified polyvinyl alcohol.
The content of the partially saponified ethylene-modified polyvinyl alcohol in the heat seal layer is 2% by mass or more and 12% by mass or less.
The degree of saponification of the partially saponified ethylene-modified polyvinyl alcohol is 86 mol% or more and 96 mol% or less.
The coating amount of the heat seal layer is 3 g / m ² or more and 7 g / m ² or less.
Barrier packaging material. The barrier packaging material according to claim 1, wherein the viscosity of the partially saponified ethylene-modified polyvinyl alcohol measured by a Brookfield viscometer of a 4% aqueous solution at 20 ° C. is 3 mPa · s or more and 50 mPa · s or less. The barrier packaging material according to claim 1 or 2, wherein the gas barrier layer contains at least one of polyvinyl alcohol and ethylene-modified polyvinyl alcohol. The barrier packaging material according to any one of claims 1 to 3, wherein the water vapor barrier layer contains a layered inorganic compound having an aspect ratio of 50 or more and an olefin-unsaturated carboxylic acid-based copolymer. A step of applying a water-based composition for a heat seal layer to a laminate provided with a water vapor barrier layer and a gas barrier layer on at least one side of a paper base material, and
It has a step of drying the coated aqueous composition for a heat seal layer to obtain a barrier packaging material in which a paper base material, a water vapor barrier layer, a gas barrier layer and a heat seal layer are provided in this order.
The aqueous composition for a heat-sealed layer contains an olefin-unsaturated carboxylic acid-based copolymer and a partially saponified ethylene-modified polyvinyl alcohol.
The content of the partially saponified ethylene-modified polyvinyl alcohol in the heat seal layer is 2% by mass or more and 12% by mass or less.
The degree of saponification of the partially saponified ethylene-modified polyvinyl alcohol is 86 mol% or more and 96 mol% or less.
The water-based composition for the heat seal layer is coated so that the coating amount after drying is 3 g / m ² or more and 7 g / m ² or less.
Manufacturing method of barrier packaging material.