JP2001301764A - Transparent pouch of oxygen barrier properties - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent bag-shaped container reducing the oxygen concentration inside and retaining the quality of a content for a long period of time. SOLUTION: A pouch main body of the transparent pouch of oxygen barrier properties is formed of a laminate at least provided with a transparent gas barrier layer and a transparent oxygen absorption film layer formed inside the transparent gas barrier layer. The pouch main body of the pouch oxygen barrier properties can be formed of a laminate formed of a base film layer, the transparent gas barrier layer, the transparent oxygen absorption layer and a heat fusion welded resin layer laminated all together from the outside to the inside in the above order. Also the transparent gas barrier layer can be constituted of a transparent deposit layer, and the transparent oxygen absorption film layer can be constituted of an oxygen absorption copolymer composed of a polyester segment and a polyolefin oligomer segment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transparent and oxygen barrier useful as a bag-like container for hermetically filling pasty foods such as miso and mayonnaise, liquid beverages such as orange juice, and pharmaceutical tablets. It relates to a pouch having properties.

[0002]

2. Description of the Related Art As a bag-shaped container for sealingly filling foods and beverages, a container formed of a laminate including a transparent vapor-deposited film obtained by vapor-depositing silicon oxide or aluminum oxide on a polyester film or the like has been used. I have. This container is transparent, has excellent gas barrier properties, and is excellent in that it uses a clean material that is suitable for the environment.However, if a crack occurs in the vapor deposition layer of the transparent vapor deposition film, oxygen passes through the film. Thus, there is a problem that the quality of the contents is deteriorated. Further, when the contents are filled in the container or when the consumer consumes a part of the contents, the quality of the contents may be deteriorated due to the air remaining in the upper space of the container.

On the other hand, a packaging container has been developed in which a container is made of a multilayer material having an oxygen absorbing layer containing an oxygen scavenger to improve the gas barrier properties of the container and to provide the container itself with a deoxidizing function. For example, Japanese Patent Application Laid-Open No. 11-58578 discloses an oxygen-permeable layer made of an oxygen-permeable polyolefin, an oxygen-absorbing layer made of an oxygen-absorbing resin composition obtained by mixing a polyolefin with an oxygen-absorbing composition, and a gas-barrier material. A packaging container formed of a deoxygenated multilayer body including a gas barrier layer and a protective layer is disclosed. But,
In this packaging container, since metallic iron is used as the oxygen scavenger, the transparency is impaired, and the metallic iron is oxidized and gradually discolored. For this reason, it is unsuitable especially for use as a transparent bag-like container in which contents such as foods and beverages can be visually recognized from the outside.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a bag-like container which is transparent, can reduce the internal oxygen concentration, and can maintain the quality of the contents for a long time.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object. As a result, when the pouch body is formed of a laminate having a specific structure, the pouch body not only has excellent transparency and gas barrier properties, but also has an internal structure. The present inventors have found that oxygen present is efficiently absorbed, and that the deterioration of the contents due to oxygen can be significantly suppressed, and the present invention has been completed.

That is, the present invention provides a transparent oxygen-barrier pouch in which the pouch body is formed of a laminate having at least a transparent gas-barrier layer and a transparent oxygen-absorbing film layer provided inside the layer. provide. This oxygen barrier pouch is formed by a laminate in which a pouch body is sequentially laminated from the outside to the inside in the order of a base film layer, a transparent gas barrier layer, a transparent oxygen-absorbing film layer, and a heat-fusible resin layer. It may be. Further, the transparent gas barrier layer may be constituted by a transparent vapor-deposited layer, and the transparent oxygen-absorbing film layer may be constituted by an oxygen-absorbing copolymer comprising a polyester segment and a polyolefin oligomer segment.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing an example of the oxygen barrier pouch of the present invention. This pouch is
It is composed of a pouch body 2 for accommodating foods, beverages, tablets of medicines and the like, and a spout 1 for taking out the foods and the like. The plug 1 includes a content take-out port 1a, a lid (cap) 1b, and a joining portion 1c for joining to the pouch body 2. In the drawing, reference numeral 2a denotes a joint portion between the laminates forming the pouch body 2 or the laminate forming the pouch body 2 and the joining portion 1c of the plug 1.

[0008] The material of the plug 1 can be appropriately selected according to the intended use. Examples thereof include olefin resins such as polyethylene and polypropylene, styrene resins such as polystyrene and ABS, and plastics such as polycarbonate, methacrylic resin, polyamide and polyacetal. A metal such as aluminum can be used. These materials can be used alone or in combination of two or more. Among these, plastics, especially polyethylene such as linear low-density polyethylene (LLDPE) and olefin-based resins such as polypropylene, which are excellent in heat-sealing property, are preferable from the viewpoints of bonding property with the pouch body 2 and sealing strength.

The shape and size of the spout 1 can be appropriately designed according to the kind, form, size, etc. of the contents to be filled in the pouch, taking into account the ease of removal and the like. The lid 1b may be mounted in any conventional manner such as a hinge type or a screw type. A conduit or the like extending inward of the pouch body may be connected to the plug 1, or a nozzle may be attached to an outer end. The plug 1 can be manufactured by a method according to its constituent materials. For example, a plastic plug can be produced by a conventional plastic molding method such as injection molding and compression molding.

The plug 1 is not always necessary. For example, the contents can be removed by peeling off the joint between the laminates forming the pouch body, cutting off the end of the pouch body, or inserting a straw. It may be a pouch that employs a removal method. However, in the present invention, a pouch with a plug is particularly useful, in which air easily remains therein and oxygen easily permeates from the resin forming the plug, and therefore a great effect is obtained by the present invention.

The pouch body 2 has a front surface and a rear surface 2.
A laminate comprising at least a transparent gas-barrier layer and a transparent oxygen-absorbing film layer provided inside the layer. It is formed with.

FIG. 2 is a sectional view showing an example of a laminate forming the pouch body 2 of the oxygen barrier pouch of the present invention.
In this laminate, a transparent substrate film layer 3, a transparent gas barrier layer 4, a transparent oxygen-absorbing film layer 5, and a heat-fusible resin layer 6 are laminated in this order from the outside.

The base film constituting the base film layer 3 is not particularly limited as long as it is transparent and has self-supporting properties. For example, a polyester film (eg, polyethylene terephthalate, polybutylene terephthalate,
Films such as polyethylene naphthalate), polyolefin-based films (eg, films of polypropylene-based resin such as polypropylene and propylene-ethylene copolymer), plastic films such as polystyrene-based films and polyamide films, and laminates thereof. Can be The plastic film may be a non-stretched film, a uniaxially or biaxially stretched film, but a stretched film, particularly a biaxially stretched film is often used. Among the above substrate films, in particular,
A polyester film such as a polyethylene terephthalate film is preferred because it has excellent printability, dimensional stability, heat resistance during heat sealing, and the like. Base film layer 3
Can be appropriately selected within a range that does not impair the strength and the like as a base material, for example, 6 to 70 μm, preferably 6 to 30 μm.
m.

At least one surface (for example, the inner surface) of the base film layer 3 may be partially printed as required. Printing is performed using a conventional printing method using a conventional printing ink (for example, gravure printing, letterpress printing,
Flat plate printing, screen printing, flexographic printing, etc.), for example, to a thickness of about 0.5 to 8 μm. The surface of the substrate film layer 3 to be printed may be subjected to a conventional surface treatment such as a corona discharge treatment or a plasma treatment in order to improve printability.

The transparent gas barrier layer 4 may be any layer that is transparent and has gas barrier properties, for example, a transparent vapor-deposited layer, an ethylene-vinyl alcohol copolymer (EV)
OH) film, stretched polyamide (O-Ny) film, polyvinylidene chloride film and the like. The transparent gas barrier layer 4 may be a single layer or multiple layers. The thickness of the transparent gas barrier layer 4 can be appropriately selected according to the type of the material constituting the layer, as long as the transparency and gas barrier properties are not impaired. Among the layers constituting the transparent gas barrier layer 4, the transparent vapor-deposited layer is particularly preferable because it is excellent in moisture resistance, fragrance retention, water resistance, chemical resistance, environmental compatibility, retort resistance and the like.

The transparent vapor-deposited layer is formed on the outer surface of the transparent oxygen-absorbing film layer 5 by using silicon oxide (SiO, SiO _2, etc.).
iO _x ) or aluminum oxide (AlO, Al ₂ O ₂ , Al ₂
It can be formed by evaporating an inorganic oxide such as Al _y O _z ) such as O ₃ . The deposition method may be any of a reactive deposition method, an electron beam heating method, and the like. The thickness of the transparent vapor-deposited layer can be appropriately set within a range that does not impair transparency or the like,
For example, 30 to 300 angstroms, preferably 5
It is about 0 to 200 angstroms.

The transparent vapor-deposited layer may be formed by vapor-depositing the above-mentioned inorganic oxide or the like on the inner surface of the base film layer 3. In this case, printing may be performed on the surface of the formed transparent evaporation layer. Further, a transparent vapor-deposited layer can be formed on the surface of a transparent plastic film (support) such as a polyethylene terephthalate film, a polyamide film, a polypropylene film, or the like, and this can be used as the transparent gas barrier layer 4. In this case, the lamination of the base film 3 and the transparent gas barrier layer 4 is performed by a conventional method such as, for example, extrusion lamination, dry lamination with an adhesive, and thermal lamination in which a heat-adhesive layer is interposed and bonded by heat. Can be.

The transparent oxygen-absorbing film layer 5 only needs to be transparent and have an oxygen-absorbing ability, and can be made of, for example, an oxygen-absorbing copolymer described in International Publication WO98 / 12244. The oxygen-absorbing copolymer is a copolymer comprising a polyester segment and a polyolefin oligomer segment, and the polyester segment has, for example, a repeating unit selected from the following formulas (1) and (2). I have.

Embedded image (Where n represents an integer of 2 to 4)

The polyolefin oligomer in the polyolefin oligomer segment may be an oxygen-absorbing oligomer such as polypropylene, poly (4-methyl) 1-pentene, polybutadiene, or a mixture thereof. A particularly preferred polyolefin oligomer is polybutadiene. The molecular weight of the polyolefin oligomer is, for example, about 100 to 10,000, preferably about 1,000 to 3,000. The ratio of the polyolefin oligomer segment is about 0.5 to 12% by weight, preferably about 2 to 8% by weight of the oxygen-absorbing copolymer.

The oxygen-absorbing copolymer is, for example, a polyester and a hydroxyl group, a carboxyl group,
It can be produced by reacting a polyolefin oligomer into which a functional group such as an amino group has been introduced, in the presence of a transesterification catalyst (such as a transition metal salt of a carboxylic acid) at a temperature of, for example, about 250 to 280 ° C. More specifically,
A polyester, a polyolefin oligomer having a functional group introduced into a terminal, and a transesterification catalyst are supplied to an extruder equipped with a heating and mixing unit, and the mixture is melt-mixed and copolymerized in the heating and mixing unit, and the product is extruded from a die. Can be obtained.

An oxidation catalyst (such as a transition metal catalyst such as a cobalt catalyst) may be added to the transparent oxygen-absorbing film layer 5 in order to increase the oxygen-absorbing ability of the oxygen-absorbing copolymer.
The thickness of the transparent oxygen-absorbing film layer 5 can be appropriately selected within a range that does not impair the transparency, the oxygen-absorbing property, and the like.
It is about 100 μm, preferably about 10 to 30 μm.

The transparent oxygen-absorbing film layer 5 may be unstretched. However, in order to enhance transparency, stiffness, tensile strength, impact resistance, etc., a stretching treatment, particularly a biaxial stretching treatment, is performed. It is preferably applied. The stretching treatment may be performed by any method such as a tenter method and a tubular film method. When performing biaxial stretching, the stretching ratio can be appropriately selected within a range that does not impair transparency, oxygen absorption, and the like. For example, the stretching ratio is about 3 to 4 times in one direction (for example, the vertical direction), and the direction perpendicular to the direction ( For example, it is about 3.5 to 4.5 times in the horizontal direction.

The heat-fusible resin constituting the heat-fusible resin layer 6 is not particularly limited as long as it is a transparent and heat-fusible resin. In addition, as a heat fusion method, a conventional method can be adopted, but heat sealing using a heat bar and impulse sealing are preferable. Typical examples of the heat-fusible resin include polyethylene (high-density polyethylene, linear low-density polyethylene, metallocene-catalyzed polyethylene, etc.), polypropylene, ethylene-vinyl acetate copolymer, and the like. In addition, in order to enhance the bonding property of the plug 1 by heat fusion, it is preferable that the resin forming the heat-fusible resin layer 6 and the material forming the plug 1 be the same or the same type. For example, in a preferred embodiment of the present invention, both the plug 1 and the heat-fusible resin layer 6 are formed of polyethylene or polypropylene such as a linear low-density polyethylene having excellent heat-fusibility and excellent moldability.

The thickness of the heat-fusible resin layer 6 can be selected within a range that does not impair the heat-fusibility and the like, and is, for example, about 10 to 200 μm, preferably about 30 to 150 μm. The heat-fusible resin layer 6 can be laminated by a conventional lamination method such as extrusion lamination and dry lamination.

In the present invention, the laminate forming the pouch body 2 may be made of another film layer, for example, a biaxially stretched polyamide film layer for improving pinhole resistance or the like as long as the transparency and handleability are not impaired. And the like. Further, the pouch body 2 does not necessarily need to be entirely formed of a laminate having the transparent gas-barrier layer and the transparent oxygen-absorbing film layer, and may partially include other layers as long as the gas-barrier property is not impaired. Transparent or opaque barrier film, for example, metallized film, aluminum foil,
It may be formed of an ethylene-vinyl alcohol copolymer film or a laminate containing them.

The pouch body 2 cuts the laminate into an appropriate shape and size, folds the bottom film,
Utilizing the heat-fusing property of the heat-fusible resin layer 6, the ends are heat-sealed with a heat bar so as to form a bag, or the two laminates are stacked and heat-sealed at three ends. Can be formed. The pouch body 2 can also be manufactured by making a bag from the laminate using an adhesive. In addition, as the pouch main body 2, various packaging forms such as a side gusset bag and a flat bag can be used in addition to a normal gusset bag. The shape of the pouch body 2 is not particularly limited, either.
Any of a standing pouch and a non-standing pouch may be used.

The connection between the plug 1 and the pouch body 2 can be performed by using an appropriate means such as a heat seal or an adhesive, depending on the material constituting these components.

In the present invention, since the laminate forming the pouch body 2 has a transparent gas-barrier layer and a transparent oxygen-absorbing film layer inside thereof, it is transparent and oxygen from the outside is Oxygen that is blocked by the transparent gas barrier layer and dissolved in the internal space and contents is absorbed by the transparent oxygen-absorbing film layer. As a result, oxygen inside the pouch can be almost completely eliminated. Further, even if the transparent gas barrier layer has some cracks, the oxygen permeated inside is captured by the transparent oxygen-absorbing film layer, so that the oxygen concentration inside the pouch does not increase. The same applies to oxygen that has passed through the plug. Therefore, quality deterioration due to oxidation of the contents can be significantly suppressed.
In addition, the transparent oxygen-absorbing film layer is generally suitable for pouches because it has a higher impact resistance than a general polyethylene terephthalate film, and a polyamide film layer or the like usually provided for imparting impact resistance is particularly required. And not.

The oxygen-barrier pouch of the present invention is transparent and has excellent oxygen-barrier properties. Thus, for example, miso, mayonnaise, ketchup, liquid food,
Pasty or highly viscous foods such as stews, jams and syrups; liquid beverages and seasonings such as orange juice, soups and dressings; solid foods such as confectionery and snacks; It is useful as a bag-like container for hermetically filling susceptible goods.

[0030]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

Example 1 An oxygen-absorbing copolymer consisting of a polyethylene terephthalate segment and a polybutadiene oligomer segment (polybutadiene oligomer segment content: 4% by weight) was extruded and subjected to a biaxial stretching treatment (longitudinal direction: 3).
2 times, transverse direction: 4 times) and a transparent oxygen-absorbing biaxially stretched film having a thickness of 12 μm was obtained. Silicon oxide was deposited on one surface of the oxygen-absorbing biaxially stretched film to form a transparent deposited layer having a thickness of 80 Å. Next, a biaxially stretched polyethylene terephthalate film (thickness: 12 μm) was laminated on the surface of the laminated film on the side of the transparent vapor-deposited layer using an adhesive, and linear low-density polyethylene was extruded on the other surface from an extruder. A heat-fusible resin layer having a thickness of 100 μm was formed to produce a transparent gas barrier laminate. This gas barrier laminate is cut into an appropriate size (width), two sheets are overlapped and a film for the bottom is sandwiched,
After forming into a bag shape by heat sealing with a heat bar, a spout (made of linear low-density polyethylene, having a mouth diameter of about 8 mm) was fitted into the upper end, and joined by heat sealing. Next, mayonnaise was filled from the mouth of the spout, leaving some space above the spout, and the cap was covered with a cap.
After leaving this at room temperature for 120 days, the cap was opened and the presence of alteration (discoloration) on the surface of the mayonnaise in contact with the upper space and the change in flavor were examined.

[0032]

According to the oxygen barrier pouch of the present invention,
Since the pouch main body is formed of a laminate including at least a transparent gas barrier layer and a transparent oxygen-absorbing film layer provided inside the layer, the pouch is transparent and excellent in appearance, and oxygen from the outside is transparent. Since the oxygen that is cut off by the gas barrier layer and remains inside is absorbed by the transparent oxygen-absorbing film layer, deterioration due to oxidation of the contents can be prevented, and high quality can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of the oxygen barrier pouch of the present invention.

FIG. 2 is a cross-sectional view showing an example of a laminate forming a pouch body of the oxygen barrier pouch of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spout 2 Pouch body 3 Base film layer 4 Transparent gas barrier layer 5 Transparent oxygen-absorbing film layer 6 Heat-fusible resin layer

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) BA04 BA07 BA10C BA10D DA01 EC18 EH23 EH66A EJ38 GB16 GB17 GB23 JD02A JD03 JD14B JL12D JN01 JN01A JN01B

Claims (3)

[Claims] 1. A transparent oxygen barrier pouch in which a pouch body is formed of a laminate having at least a transparent gas barrier layer and a transparent oxygen absorbing film layer provided inside the layer. 2. The pouch body is formed from a laminate in which a base film layer, a transparent gas barrier layer, a transparent oxygen-absorbing film layer, and a heat-fusible resin layer are laminated in this order from the outside to the inside. The oxygen barrier pouch according to claim 1. 3. The transparent gas-barrier layer comprises a transparent vapor-deposited layer, and the transparent oxygen-absorbing film layer comprises an oxygen-absorbing copolymer comprising a polyester segment and a polyolefin oligomer segment. The oxygen barrier pouch according to the above.