JP2021017282A - Packaging bag - Google Patents

Abstract

To provide a packaging bag that is made of laminated material, can store strongly basic contents, and can ensure durability and peeling strength of a laminate that makes up the packaging bag by determining the composition of the laminate that allows stable acquisition of a measurement value of peeling strength with high strength when the laminate has a gas barrier layer made of metal leaf.SOLUTION: A packaging bag that can store strongly basic contents uses a plastic film as a base material and is composed of a laminate in which a printing layer, an intermediate base material layer, a gas barrier layer made of metal foil, a surface modification layer thereof, an extruded resin layer, and a sealant layer are sequentially laminated. The loop stiffness strength of the laminated portion of the extruded resin layer and the sealant layer is 5.5 mN or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a packaging bag. In particular, a packaging bag capable of storing contents containing a strongly basic substance such as a hair coloring agent, for example, monoethanolamine, between the gas barrier layer and the sealant layer of the laminate constituting the packaging bag. It relates to a packaging bag having excellent peeling strength.

In addition to its convenience and design, many types of packaging bags have been put into practical use according to the contents and usage environment. In particular, in recent years, packaging bags have been formed by making a laminate using a plastic film as a base film, having a sealant layer, and laminating a plastic film or the like capable of adding a necessary function, in various fields. It is put to practical use in.

In general, the role of packaging containers such as packaging bags is to protect the contents from various external environments and external forces, but depending on the field of use, emphasis is placed on preventing the contents from leaking to the outside. In the case of contents with strong odor or the like, it may be important to prevent the odor from seeping out or leaking to the outside.

For example, a hair coloring agent for dyeing hair contains a strong basic substance such as monoethanolamine or ammonia as a component of a chemical solution containing a dye, and therefore has a strong odor, so that it has resistance to contents and gas barrier properties. Often required.

On the other hand, since the hair color is a strongly basic content, when a metal foil such as an aluminum foil is used for the gas barrier layer, corrosion and a decrease in the adhesive strength of the laminate or the peeling strength between the layers are reduced. It must be prevented, and it is also necessary to improve the durability and peel strength of the components of the laminate constituting the packaging bag, such as preventing the deterioration of the plastic film.

As a method for achieving both gas barrier properties and strong basicity, Patent Document 1 proposes a packaging bag in which aluminum foil is subjected to chemical conversion treatment to suppress corrosion of the aluminum foil layer. Further, prior document 2 proposes a packaging bag made of a laminated body using an aluminum foil as a gas barrier layer, and aims to solve the problem by providing an extruded layer of a thermoplastic resin in order to improve the peel strength of the laminated body. I have a suggestion.

However, in any case, since the hard aluminum foil layer and the flexible thermoplastic resin layer are laminated adjacent to each other in the laminated body, the load of bending on the laminated body, particularly the thermoplastic resin layer, is applied. Therefore, it is considered that there is a problem that the measured value of the peel strength is not stable.

Japanese Patent No. 5584970 Japanese Unexamined Patent Publication No. 2003-81285

The present invention has been made in view of such a situation, and when the packaging bag is made of a laminated body, can store strongly basic contents, and the laminated body has a gas barrier layer made of a metal leaf, it is peeled off. An object of the present invention is to determine the structure of a laminate in which a measured value of strength can be stably obtained with high strength, and to provide a packaging bag capable of ensuring the durability and peeling strength of the laminate constituting the packaging bag. ..

The invention according to claim 1 is a means for solving the above problems.
A packaging bag that can store strongly basic contents
This packaging bag is made of a laminated body in which a printing layer, an intermediate base material layer, a gas barrier layer made of a metal foil, a surface modification layer thereof, an extruded resin layer, and a sealant layer are sequentially laminated on a plastic film as a base material.
It is a packaging bag characterized in that the loop stiffness strength of the laminated portion of the extruded resin layer and the sealant layer is 5.5 mN or more.

Further, the invention according to claim 2 is
The packaging bag according to claim 1, wherein the gas barrier layer is made of aluminum or an aluminum alloy having a thickness of 5 μm or more and 50 μm or less.

Further, the invention according to claim 3 is
The packaging according to claim 1 or 2, wherein the surface-modified layer is composed of an inorganic film containing Zr, Cr, or a salt thereof, and an organic polymer film covering the inorganic film. It is a bag.

Further, the invention according to claim 4 is
The gas barrier layer and its surface modification layer and the extruded resin layer are laminated via an adhesive layer.
The packaging bag according to any one of claims 1 to 3, wherein the adhesive layer contains a bifunctional isocyanate monomer as a main component of a trifunctionalized isocyanate monomer derivative. ..

Further, the invention according to claim 5 is
The packaging bag according to any one of claims 1 to 4, wherein the extruded resin layer is made of a thermoplastic polyethylene resin having a thickness of 15 μm or more and 30 μm or less.

Further, the invention according to claim 6 is
The packaging bag according to any one of claims 1 to 5, wherein the sealant layer has a thickness of 20 μm or more and 80 μm or less.

According to the present invention, when the packaging bag is made of a laminated body, the packaging bag is made of a laminated body, a strongly basic content can be stored, and the laminated body has a gas barrier layer made of a metal leaf, it is peeled off. It is possible to determine the configuration of a laminate in which a measured value of strength can be stably obtained with high strength, and to provide a packaging bag capable of ensuring the durability and peeling strength of the laminate constituting the packaging bag. ..

FIG. 1 is a schematic partial cross-sectional view for explaining a laminated body constituting the packaging bag according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to FIG. However, the present invention is not limited to the examples shown here. The present invention is limited by the claims.

FIG. 1 is a schematic partial cross-sectional view for explaining a laminated body constituting the packaging bag according to the present invention.

The packaging bag according to the present invention is a packaging bag capable of storing strongly basic contents. For example, a hair coloring agent for dyeing hair is an example of a strongly basic content. In this case, the odor is generally strong, and gas barrier property is required in addition to content resistance.

This packaging bag uses a plastic film as a base film (1), and at least a printing layer (2), an intermediate base material layer (3), a gas barrier layer (4) made of a metal foil, and a surface modification layer (5) thereof. ), The extruded resin layer (7), and the sealant layer (8) are sequentially laminated to form a laminated body (10).

In the example shown in FIG. 1, a gas barrier layer (4) made of a metal foil, a surface modification layer (5) thereof, and an extruded resin layer (7) are laminated via an adhesive layer (6). This is an example.

Further, as a feature of the laminated body (10) constituting the packaging bag according to the present invention, the loop stiffness strength of the laminated portion (9) of the extruded resin layer (7) and the sealant layer (8) is 5.5 mN or more. Is what you do.

In the process of diligently studying the present invention, by setting the value of the laminated portion (9) to this range, the gas barrier layer (4) made of a metal leaf having the surface modification layer (5) is laminated. It is possible to provide a packaging bag capable of ensuring the durability and peeling strength of the laminate (10) constituting the packaging bag because the peeling strength from the portion (9) can be stably obtained with high strength. I found it possible.

Incidentally, in the present invention, the loop stiffness strength is a measured value of rigidity, and when a cylindrical sample having a width of 15 mm and a diameter of 50 mm is compressed vertically and the cross section of the cylinder becomes elliptical, the minor axis thereof is The stress is measured when compressed to a 20 mm elliptical shape.

That is, when the laminate (10) constituting the packaging bag according to the present invention has, for example, a gas barrier layer (4) made of a metal foil, the metal material has high rigidity, and therefore the extruded resin layer (7) adjacent thereto has high rigidity. ) And the sealant layer (8), if there is a deviation from the rigidity of the laminated portion (9), the measured value of the peel strength may not be stable, but if the rigidity is within the range specified by the present invention, it is high. The measured value is stable, and the peeling strength as a packaging bag for storing strongly basic contents can be guaranteed.

Further, in our further study process, we have found that each layer constituting the laminated body (10) also has a more preferable material or layer thickness.

The surface modification layer (5) can be composed of an inorganic film containing Zr, Cr, or a salt thereof, and an organic polymer film covering the inorganic film, which more preferably enhances the degree of peeling between layers. be able to.

The gas barrier layer (4) made of metal foil, the surface modification layer (5) thereof, and the extruded resin (7) layer can be laminated via an adhesive layer (6), and at this time, the adhesive layer ( 6) is more preferably a bifunctional isocyanate monomer containing a trifunctionalized isocyanate monomer derivative as a main component.

The gas barrier layer (4) made of metal foil is sufficiently made of aluminum or an aluminum alloy having a thickness of 5 μm or more and 50 μm or less in terms of gas barrier performance, and as a laminate (10) constituting a packaging bag. Appropriate.

The sealant layer (8) having a thickness of 20 μm or more and 80 μm or less is suitable for making a laminated body (10) constituting a packaging bag as the sealant layer (8), and also as a packaging bag. Sufficient strength can be obtained for adhesion performance and the like.

Further, the materials of each layer of the laminate (10) constituting the packaging bag according to the present invention will be individually described.

In the laminate (10), the base film (1) and the intermediate base material layer (3) are layers made of a plastic film. The plastic film is a film made of a polymer resin composition, for example, polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide (nylon-6, nylon-66, etc.), Polyethylene or the like can be used and is appropriately selected according to the application.

In particular, when polypropylene or polyethylene terephthalate is used as a plastic film, it is more preferable in terms of film strength and price. In addition, when a stretched polyamide film is used, it is possible to impart toughness against piercing and impact resistance to the laminated body (10).

Further, the plastic film can be laminated with another layer via an adhesive layer to form a laminated body. The layer structure of the laminated body (10), its material structure, thickness, and the like can be appropriately designed according to the required quality for the packaging bag.

As described above, in the laminated body (10), when the gas barrier layer (4) made of a metal foil is made of aluminum or an aluminum alloy having a thickness of 5 μm or more and 50 μm or less, the gas barrier performance is sufficient. Moreover, it is suitable as a laminate (10) constituting a packaging bag.

At the same time, when aluminum or an aluminum alloy is in this thickness range, it is possible to obtain properties required for packaging bags such as flexibility, and roll-to-roll processing is possible in the processing process. It can also be excellent in productivity.
The gas barrier layer (4) made of this metal foil has a surface modification layer (5). As described above, the surface modification layer (5) can be composed of an inorganic film containing Zr, Cr, or a salt thereof, and an organic polymer film covering the inorganic film, which is more preferable for delamination. It is possible to increase the degree of business.

The extruded resin layer (7) is located between the sealant layer (8) and the gas barrier layer (4) made of a metal foil, and is an effective layer for improving the peel strength between the layers. For example, thermoplastic low-density polyethylene. Resin or the like can be used.

If necessary, an adhesive layer (6) is interposed between the surface modification layer (5) provided on the gas barrier layer (4) made of metal foil and the extruded resin layer (7) to form this portion. The peel strength can be improved.
Further, the extruded resin layer (7) is laminated with the sealant layer (8), and as a part thereof, it is effective for improving the sealing property such as heat sealing.

The sealant layer (8) is formed by stacking two laminates (10) so that the sealant layers (8) face each other, heating and pressurizing them to heat-seal them, and adhering them to each other. Allows you to.

As the material of the sealant layer (8), a polyolefin resin is generally used among the thermoplastic resins, specifically, low density polyethylene resin (LDPE), medium density polyethylene resin (MDPE), and linear low density resin. Ethylene-based resins such as density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, ethylene-methacrylic acid resin copolymer, blended resin of polyethylene and polybutene, and Polypropylene resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer can be used.

To form the sealant layer (8), a molten resin can be formed by using an extruder or the like to form a layer on the laminate. Alternatively, it is also possible to form a sealant layer on the surface of the laminated body (10) by laminating a material that has been formed into a film in advance by laminating.

The printing layer (2) is a layer that can be seen from the outside of the packaging bag in a laminate based on a plastic film for the purpose of improving the image as a product, displaying necessary information about the contents, and improving the design. Can be provided. The printing layer (2) may be provided on the outermost layer of the packaging bag.

Further, the printing layer (2) may be provided on a part of the packaging bag, or may be provided over the entire surface of the packaging bag. Alternatively, as a method of providing the display unit without using the printing layer (2), for example, a printed sticker can be attached to the surface of the packaging bag.

Here, the printing ink and the printing method of the printing layer (2) are not particularly limited, but among the known printing methods, printability on a plastic film, designability such as color tone, adhesion, and the like. Others may be selected as appropriate in consideration of safety and the like.

The printing method can be selected from known printing methods such as a gravure printing method, an offset printing method, a gravure offset printing method, a flexo printing method, a silk screen printing method, and an inkjet printing method. Above all, the gravure printing method can be preferably used in terms of productivity, printability on a plastic film, and high definition of a pattern.

In this way, according to the present invention, the packaging bag is made of a laminated body (10) and can store strongly basic contents, and the laminated body (10) is a gas barrier layer (4) made of a metal leaf. When it is provided, the structure of the laminated body (10) that can stably obtain the measured value of the peeling strength with high strength can be determined, and the durability and peeling strength of the laminated body (10) constituting the packaging bag can be ensured. , It is possible to provide packaging bags.

Hereinafter, the present invention will be described in more detail with reference to Example 1, Example 2, and Comparative Example 1. However, the present invention is not limited to the examples shown here. The present invention is limited by the claims. Further, the layer structure will be described with reference to FIG.

An evaluation sample of the laminated body (10) was prepared, and the loop stiffness strength of only the laminated portion (9) of the extruded resin layer (7) and the sealant layer (8) of the laminated body (10) was measured.

At this time, in the present invention, the range of the loop stiffness strength is set to 5.5 mN or more, and therefore Examples 1 and 2 correspond to this.
On the other hand, in Comparative Example 1, it deviates from this range.

As a sample evaluation method, the peel strength of the laminated portion (11) of the gas barrier layer of the laminated body (10) and the laminated portion (9) of the extruded resin layer (7) and the sealant layer (8) was measured.

<Example 1>
The laminated portion (11) of the gas barrier layer of the laminated body (10) has the following layer structure.
From the outside of the packaging bag
Stretched polyamide film (Bonil w made by Kojin Co., Ltd. thickness 15 μm + printing layer by gravure printing method (white) / polyethylene terephthalate film layer (FE2001 made by Futamura Chemical Co., Ltd. thickness 12 μm) / aluminum foil (8079 material made by Toyo Aluminum Co., Ltd. thickness 9 μm) ..

These layers were bonded together using the following urethane-based adhesive.
Main agent: Takelac A626 manufactured by Mitsui Chemicals, Inc.
Hardener: Takenate A50 manufactured by Mitsui Chemicals, Inc.

Furthermore, on the surface of the aluminum foil,
A surface-treated layer (5) was formed by surface-treating with a Zr-based coating agent (Surf Coat NR-X manufactured by Nippon Paint Surf Chemicals).

An adhesive containing a biuret type of hexamethylene diisocyanate as a main component (Takelac A65 manufactured by Mitsui Chemicals, Inc.) was applied to the surface modified layer (5).
Then, low-density polyethylene (LC600A manufactured by Japan Polyethylene Corporation) was extruded and laminated as the extruded resin layer (7).

Further, the sealant layer (8) has a gas barrier layer (4) made of a metal foil and a sealant layer (8), which is bonded to a linear low-density polyethylene resin film (LL-MTNST manufactured by Futamura Chemical Co., Ltd.). A laminated body (10) was formed.

This laminate (10) was heat-treated through a thermal laminating machine at 160 ° C. and 1 m / min.
Subsequently, the laminated portion (11) of the gas barrier layer of the laminated body, which is the portion including the aluminum foil layer, is peeled off from the extruded resin layer (7), and the peeling strength is measured by a tensile tester. The loop stiffness strength of only the laminated portion (9) of the extruded resin layer (7) and the sealant layer (8) was measured.

For this measurement, a loop stiffness tester manufactured by Toyo Seiki Seisakusho Co., Ltd. was used to measure a sample having a width of 15 mm and a diameter of 50 mm.
The loop stiffness strength of only the laminated portion (9) of the extruded resin layer (7) and the sealant layer (8) was 7.4 mN.

<Example 2>
The layer structure of the laminated body is the same as that of the first embodiment.
However, with respect to Example 1, the heat treatment was performed at 200 ° C. for 1 minute using an oven instead of the thermal lamination of the laminate. Only this part is different from the first embodiment.
The loop stiffness strength of only the laminated portion (9) of the extruded resin layer (7) and the sealant layer (8) was 5.5 mN.

<Comparative example 1>
The layer structure of the laminated body is the same as that of the first embodiment.
However, the difference from Example 1 is that the laminated body is not thermally laminated with respect to Example 1.
The loop stiffness strength of only the laminated portion (9) of the extruded resin layer (7) and the sealant layer (8) was 4.5 mN.
This value deviates downward from 5.5 mN, which is the specified range of the loop stiffness strength according to the present invention.

The evaluation results are shown in Table 1.

As is clear from the results shown in Table 1, in Examples 1 and 2, where the loop stiffness strength is within the specified range according to the present invention, the peel strengths are 5.3N and 5.0N, respectively. A sufficiently high value is obtained.

On the other hand, in Comparative Example 1 in which the loop stiffness strength deviates from the range specified by the present invention, the peel strength is 1.5N, which is significantly lower than that in Examples 1 and 2. It has become.

As described above, in the laminated body constituting the packaging bag according to the present invention, when the loop stiffness strength is within the specified range according to the present invention, the laminated portion (11) of the gas barrier layer and the extruded resin layer (7) It has been verified that the sealant layer (8) can be stably obtained with a high isolation strength from the laminated portion (9).

This is a desirable and necessary property as a packaging bag capable of storing strongly basic contents, and is considered to show the effectiveness for solving the problem of the present invention.

In this way, when the packaging bag is made of a laminate, can store strongly basic contents, and the laminate has a gas barrier layer, a measured value of peel strength can be stably obtained with high strength. It was possible to determine the structure of the laminated body and verify that it is possible to provide a packaging bag capable of ensuring the durability and peeling strength of the laminated body constituting the packaging bag.

1 ... Base film 2 ... Printing layer 3 ... Intermediate base layer 4 ... Gas barrier layer 5 made of metal foil ... Surface modification layer 6 ... Adhesive layer 7 ... Extruded Resin layer 8 ... Sealant layer 9 ... Laminated portion 10 ... Laminated body 11 ... Laminated portion of gas barrier layer

Claims (6)

A packaging bag that can store strongly basic contents
This packaging bag is made of a laminated body in which a printing layer, an intermediate base material layer, a gas barrier layer made of a metal foil, a surface modification layer thereof, an extruded resin layer, and a sealant layer are sequentially laminated on a plastic film as a base material.
A packaging bag characterized in that the loop stiffness strength of the laminated portion of the extruded resin layer and the sealant layer is 5.5 mN or more. The packaging bag according to claim 1, wherein the gas barrier layer is made of aluminum or an aluminum alloy having a thickness of 5 μm or more and 50 μm or less. The packaging according to claim 1 or 2, wherein the surface-modified layer is composed of an inorganic film containing Zr, Cr, or a salt thereof, and an organic polymer film covering the inorganic film. bag. The gas barrier layer and its surface modification layer and the extruded resin layer are laminated via an adhesive layer.
The packaging bag according to any one of claims 1 to 3, wherein the adhesive layer contains a bifunctional isocyanate monomer as a main component of a trifunctionalized isocyanate monomer derivative. The packaging bag according to any one of claims 1 to 4, wherein the extruded resin layer is made of a thermoplastic polyethylene resin having a thickness of 15 μm or more and 30 μm or less. The packaging bag according to any one of claims 1 to 5, wherein the sealant layer has a thickness of 20 μm or more and 80 μm or less.

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