JP2022105396A - Packaging bag and content filling body - Google Patents

Abstract

To provide a packaging bag excellent in pressure-resistance that can restrict bag tear for a long time even when a content that heightens inner pressure such as carbonated drink is filled in, and provide a content filling body using the packaging bag.SOLUTION: A packaging bag 1 has a two-layer structure with an inner bag 10 and an outer bag 20 and is formed of an approximate square. The outer bag 20 has at least a sealant layer on the innermost layer and is formed of a first laminated body 11 with polyolefin resin layers provided on the sides of a mesh structure layer made of polyolefin resin. At one peripheral edge of the approximate square, the inner bag 10 is folded and is not anchored with the outer bag 20, and at the other three peripheral edges, the inner bag 10 is sandwiched by the outer bag 20 and anchored.SELECTED DRAWING: Figure 5

Description

The present invention relates to a packaging bag and a filling material.

As a beverage container for jelly beverages and the like, a packaging bag such as a packaging bag with a spout in which a spout is attached to a soft packaging material is known. However, such packaging bags are inferior in pressure resistance to rigid containers such as metal cans, bottles, and PET bottles. When the packaging bag is filled with a carbonated drink, the soft packaging material is stretched and torn, or the seal portion connecting the soft packaging materials is peeled off, so that the bag is easily torn. Therefore, a packaging bag made of a soft packaging material is not suitable for a container filled with contents such as carbonated drinks having a high internal pressure.

A flexible packaging container made of a flexible packaging material in consideration of pressure resistance has also been proposed. Patent Document 1 includes an inner bag body in which a liquid is stored and an outer bag body that covers the inner bag body from the outside, and the inner volume of the inner bag body is equal to or larger than the inner volume of the outer bag body. The container is disclosed. In Patent Document 2, pressure-resistant packaging having a sealant layer and having laminated films whose tensile strength, thickness and Young's modulus are controlled within a specific range are laminated to form a peripheral seal portion whose sealing strength is controlled to a specific value or higher. The bag is disclosed.

Japanese Unexamined Patent Publication No. 2018-047919 Japanese Unexamined Patent Publication No. 2014-065531

However, in the flexible packaging container of Patent Document 1, although the inner bag body is supported by the outer bag body, there is a problem that the film extends in both the inner bag body and the outer bag body. It is difficult to sufficiently suppress bag breakage. Further, in the pressure-resistant packaging bag of Patent Document 2, although the bag can be prevented from breaking due to the internal pressure, the disclosed shape is not suitable for drinking directly from the spout even if it is filled with a carbonated drink.

INDUSTRIAL APPLICABILITY The present invention has an excellent pressure-resistant strength that can suppress bag breakage even when filled with contents such as carbonated drinks that increase the internal pressure, and further, by providing a spout, the contents can be drunk directly from the spout. , And a content filler using the same.

The present invention has the following aspects.
[1] A packaging bag having a double structure having an inner bag and an outer bag, and having a substantially four-sided structure, the inner bag has a mesh structure layer made of a polyolefin resin and both sides of the mesh structure layer. It is composed of a first laminated body including a provided polyolefin resin layer, and the inner bag is folded back on at least one peripheral portion of the substantially four sides, and the outer bag is not fixed to the outer bag. The other peripheral edge is a packaging bag in which the inner bag is fixed while being sandwiched between the outer bags.
[2] The inner bag is folded back on one of the substantially four sides and is not fixed to the outer bag, and the inner bag is the inner bag on the other three peripheral portions of the substantially four sides. The packaging bag according to [1], which is fixed while being sandwiched between outer bags.
[3] The packaging bag according to [1] or [2], wherein the outer bag comprises a second laminated body including a sealant layer and a gas barrier layer provided outside the sealant layer.
[4] The packaging bag according to any one of [1] to [3], further comprising a spout.
[5] The packaging bag according to any one of [1] to [4], wherein the outer bag has a gusset at the bottom.
[6] A content-filled body in which the contents are filled in the packaging bag according to any one of [1] to [5].
[7] The content filler according to [6], wherein the content is a carbon dioxide gas-containing beverage.

According to the present invention, it is excellent in pressure resistance that can suppress bag breakage even when filled with contents such as carbonated drinks having a high internal pressure, and further, by providing a spout, the contents can be drunk directly from the spout. A packaging bag and a content filling material using the same can be provided.

It is a front view of the flat state which showed an example of the packaging bag of this invention. FIG. 3 is a sectional view taken along the line AA of the packaging bag of FIG. It is BB sectional view of the packaging bag of FIG. It is a DD sectional view of the packaging bag of FIG. FIG. 3 is a sectional view taken along the line CC of the packaging bag of FIG. It is an enlarged cross-sectional view which showed the appearance that the packing bag was filled with the contents, and the vicinity of a side seal portion expanded.

[Packaging bag]
Hereinafter, the packaging bag according to the embodiment of the present invention will be described with reference to the drawings. It should be noted that each of the embodiments shown below is specifically described in order to better understand the gist of the invention, and is not limited to the present invention unless otherwise specified. In addition, the drawings used in the following description may be shown by enlarging the main parts for convenience in order to make the features of the present invention easy to understand, and the dimensional ratios and the like of each component are the same as the actual ones. It is not always the case.

In the present invention, the packaging bag provided with the spout and the packaging bag not provided with the spout have the same form except for the presence or absence of the spout. Hereinafter, as an embodiment of the packaging bag of the present invention, an example of a packaging bag provided with a spout will be described in detail.

As shown in FIGS. 1 and 2, the packaging bag 1 includes an inner bag 10, an outer bag 20, and a spout 30. The packaging bag 1 has an upper seal portion 2 extending in the width direction at the top, a side seal portion 3 extending in the height direction on both side portions in the width direction, and a bottom seal portion 4 extending in the width direction at the bottom. It is a formed, approximately square shape. Here, the substantially four sides may have a spout and may have a chamfered corner. In this way, the packaging bag 1 is sealed by forming a sealing portion on the peripheral portion. The packaging bag 1 has a double structure in which the inner bag 10 is provided inside the outer bag 20, and the inside of the inner bag 10 is a filling portion for filling the contents. The spout 30 is attached to the upper seal portion 2 in a state of being sandwiched inside the inner bag 10.

The outer bag 20 is a so-called standing pouch having a pair of flat surface portions 21 and 22 and a bottom portion 23 provided with a gusset. The pair of flat surface portions 21 and 22 and the bottom portion 23 are each formed of a sheet material described later. The outer bag 20 is not limited to the standing pouch.

The front view shape of the pair of flat surface portions 21 and 22 is a rectangular shape consisting of substantially four sides.
The front view shape of the bottom portion 23 is rectangular. The front view shape of the bottom portion 23 is not limited to the rectangular shape.

In the outer bag 20, the pair of flat surface portions 21 and 22 are arranged so that their surfaces face each other, and the bottom portion 23 is arranged on the bottom side between the pair of flat surface portions 21 and 22. The bottom portion 23 comprises a gusset having a fold line 23a that is folded upward in a valley fold between the pair of flat surfaces 21 and 22 and extends from one side edge in the width direction to the other side edge.

The inner bag 10 is made of a first laminated body 11 which is a sheet material having a multi-layer structure, which will be described later.
The front view shape of the inner bag 10 is a rectangular shape consisting of substantially four sides.

The peripheral edge of one of the substantially four sides of the packaging bag 1 is not fixed to the outer bag 20 by being folded back in the vertical direction so that the first laminated body 11 forming the inner bag 10 has a W-shaped cross section. It is sealed only with the outer bag 20. The inner bag 10 is arranged between the pair of flat surface portions 21 and 22 of the outer bag 20 in a state where the folded portion thereof is the bottom portion 12. In this example, the bottom portion 12 of the inner bag 10 is further folded upward in a valley fold so as to follow the gusset shape of the bottom portion 23 of the outer bag 20. The peripheral edge portion of one of the substantially four sides of the packaging bag 1 forms the peripheral edge portion of the bottom of the packaging bag 1, and the portion sealed only by the outer bag 20 is the bottom sealing portion 4.

As shown in FIG. 2, in the bottom sealing portion 4 of the packaging bag 1, the lower edge portion 23d of the bottom portion 23 folded in the valley fold on the flat surface portion 21 side and the lower edge portion 21c of the flat surface portion 21 are joined by heat welding. Has been done. Further, the lower edge portion 23e on the flat surface portion 22 side of the bottom portion 23 folded into the valley fold and the lower edge portion 22c of the flat surface portion 22 are joined by heat welding. That is, in the bottom seal portion 4, the two sheet materials of the lower edge portion 23d of the bottom portion 23 and the lower edge portion 21c of the flat surface portion 21, and the lower edge portion 23e of the bottom portion 23 and the lower edge portion 22c of the flat surface portion 22. The two sheet materials are joined by heat welding.

The inner bag 10 is sandwiched between the outer bags 20 in the upper and both side peripheral portions, which are the peripheral edges of the other three sides of the packaging bag 1, that is, the peripheral edges of the three sides other than the peripheral edge of the bottom. , It is sealed and fixed by the upper seal portion 2 and the side seal portion 3.
As shown in FIG. 3, in the upper sealing portion 2 of the packaging bag 1, the superposed upper edge portions 11a and 11a of the first laminated body 11 in the inner bag 10 are the upper edge portions 21a of the flat surface portion 21 in the outer bag 20. And the upper edge portion 22a of the flat surface portion 22, and they are joined to each other by heat welding. That is, in the upper sealing portion 2 of the packaging bag 1, the upper edge portion 21a of the flat surface portion 21, the two upper edge portions 11a and 11a of the first laminated body 11, and the upper edge portion 22a of the flat surface portion 22 are four pieces. The sheet materials are laminated in this order and joined to each other by heat welding.

As shown in FIG. 2, in the central portion in the width direction of the upper seal portion 2 of the packaging bag 1, the first laminated body 11 is sandwiched between the two upper edge portions 11a and 11a of the first laminated body 11. The upper edges 11a and 11a of the body 11 and the spout 30 are joined by heat welding.

As shown in FIG. 4, on the flat surface portion 21 side of the portion where the bottom portion 23 exists in both side seal portions 3 in the width direction, the side edge portion 23b facing the flat surface portion 21 of the bottom portion 23 folded in the valley fold. , The side edge portions 11b, 11b of the first laminated body 11 in the inner bag 10 are sandwiched between the side edge portions 21b of the flat surface portion 21, and they are joined by heat welding. Similarly, on the flat surface portion 22 side of the portion of the side seal portion 3 where the bottom portion 23 exists, the side edge portion 23c facing the flat surface portion 22 of the bottom portion 23 folded in the valley fold and the side edge portion 22b of the flat surface portion 22. The overlapped side edge portions 11b, 11b of the first laminated body 11 in the inner bag 10 are sandwiched between the two, and they are joined by heat welding. In addition, in FIG. 4, in the side seal portion 3 of the portion where the bottom portion 23 exists, it seems that the side edge portion 23b and the side edge portion 23c of the bottom portion 23 are directly joined, but in the present embodiment, it seems that the side edge portion 23c is directly joined. The side edge portions 11b and 11b of the first laminated body 11 are joined to each other through a through hole (not shown) penetrating the side edge portion 23b and the side edge portion 23c. Alternatively, the side edge portion 21b and the side edge portion 22b of the flat surface portion 21 are joined to each other through a through hole penetrating the side edge portions 23b, 23c and the side edge portions 11b, 11b of the first laminated body 11. The side edge portion 23b and the side edge portion 23c of the bottom portion 23 may be directly joined by a method such as ultrasonic sealing.

As shown in FIGS. 4 and 5, above the portion of the side seal portions 3 on both sides in the width direction where the bottom portion 23 exists, the overlapped side edge portions 11b of the first laminated body 11 in the inner bag 10 11b is sandwiched between the side edge portion 21b of the flat surface portion 21 and the side edge portion 22b of the flat surface portion 22 in the outer bag 20, and they are joined to each other by heat welding. That is, in the portion where the bottom portion 23 of the side sealing portion 3 of the packaging bag 1 does not exist, the side edge portions 21b of the flat surface portion 21, the two side edge portions 11b and 11b of the first laminated body 11, and the flat surface portion 22 The four sheet materials of the side edge portion 22b are laminated in this order and joined to each other by heat welding.

In the bottom sealing portion 4 of the packaging bag 1, between the lower edge portion 23d of the bottom portion 23 and the lower edge portion 21c of the flat surface portion 21, and between the lower edge portion 23e of the bottom portion 23 and the lower edge portion 22c of the flat surface portion 22. The first laminated body 11 is not sandwiched. As described above, in the inner bag 10, only the upper edge portions 11a, 11a of the first laminated body 11 and the side edge portions 11b, 11b on both sides in the width direction, that is, the three peripheral edges other than the bottom portion 12, are the outer bag 20. The bottom portion 12 of the first laminated body 11 is not joined by the bottom sealing portion 4 while being sandwiched between the pair of flat surface portions 21 and 22.

(Inner bag)
The first laminated body 11 forming the inner bag 10 includes a network structure layer made of a polyolefin resin and a polyolefin resin layer provided on both sides of the network structure layer. That is, in the inner bag 10, the polyolefin resin layer is provided on both the inside and the outside of the network structure layer made of the polyolefin resin. In the inner bag 10, the polyolefin resin layer inside the network structure layer in the first laminated body 11 is the innermost layer in contact with the contents. In the inner bag 10, the polyolefin resin layer outside the network structure layer is an outer layer that is heat-welded to the sealant layer of the outer bag 20, which will be described later.

The network structure layer is made of a polyolefin resin.
Examples of the polyolefin resin forming the network structure layer include polyethylene resin and polypropylene resin. The polyolefin resin layer described later is preferably a layer made of polyethylene resin in order to improve the adhesive strength of each sealing portion, and the polyolefin forming the network structure layer can be firmly bonded to the polyolefin resin layer. As the resin, polyethylene resin is preferable. As the polyolefin resin forming the network structure layer, one type may be used alone, or two or more types may be used in combination.

Examples of the mode of the network structure layer include a layer made of a lattice network such as a fiber orthogonal laminated non-woven fabric, a split fiber non-woven fabric, and a net-like material. Here, the "fiber orthogonal laminated non-woven fabric" is manufactured by laminating the orientation axes of the vertical web and the horizontal web formed by splitting or slitting a polyolefin film and stretching them so as to be orthogonal to each other. Is to be done.

In the fiber orthogonal laminated non-woven fabric, since the two vertical webs and the horizontal web are laminated with their orientation axes orthogonal to each other, the strength balance between the vertical direction and the horizontal direction is excellent. Examples of commercially available fiber orthogonal laminated non-woven fabrics include Warif (manufactured by ENEOS Technomaterial Co., Ltd., a registered trademark).

When the network structure layer is, for example, a fiber orthogonal laminated non-woven fabric, the basis weight is preferably 15 g / m ² or more, and more preferably 30 g / m ² or more. When the basis weight of the fiber orthogonal laminated non-woven fabric is equal to or higher than the lower limit of the above range, the tensile strength and the tensile elongation are excellent, and when the first laminated body 11 is used as the inner bag of the packaging bag 1, the internal pressure of the contents increases. It is preferable because it is hard to stretch and tear. The higher the basis weight of the fiber orthogonal laminated non-woven fabric, the better the upper limit, but the upper limit of the basis weight of the commercially available fiber orthogonal laminated nonwoven fabric is about 47 g / m ² . Here, the basis weight represents the mass per 1 m ² .

Examples of the polyolefin resin forming the polyolefin resin layer include polyethylene resin such as low density polyethylene (LDPE), medium density polyethylene, high density polyethylene (HDPE), linear low density polyethylene (LLDPE), and polypropylene resin. .. Above all, it is preferable that the resin is of the same type that can be heat-welded to the sealant layer of the sheet material constituting the outer bag 20. As the polyolefin resin forming the polyolefin resin layer, one type may be used alone, or two or more types may be used in combination. As described above, the polyolefin resin is preferably a polyethylene resin. The polyolefin resin layer may be an unstretched film or may be extruded into a layer on the network structure layer by an extrusion laminating method.

The polyolefin resin forming the inner polyolefin resin layer of the network structure layer and the polyolefin resin forming the outer polyolefin resin layer may be the same type or different types. However, in the packaging bag 1, the sealed portion sealed with the inner bag 10 sandwiched between the outer bags 20 and the sealed portion sealed only with the outer bag 20 can be heat-sealed under the same conditions. It is preferable that the inner polyolefin resin layer and the outer polyolefin resin layer of the network structure layer are of the same type. That is, in the sealing portion of the packaging bag 1 in which the inner bag 10 is sandwiched between the outer bags 20 and sealed, the polyolefin resin layers inside the mesh structure layer are sealed with each other, and the polyolefin resin layer outside the mesh structure layer is sealed. And the sealant layer of the sheet material constituting the outer bag 20 are sealed by heat sealing. On the other hand, in the seal portion sealed only by the outer bag 20, the sealant layers of the sheet material constituting the outer bag 20 are sealed. Therefore, in order for the seal portion sealed with the inner bag 10 sandwiched between the outer bags 20 and the seal portion sealed only with the outer bag 20 to be heat-sealed under the same conditions, the mesh structure layer It is preferable that the inner polyolefin resin layer, the outer polyolefin resin layer, and the sealant layer of the sheet material constituting the outer bag are all the same type of resin. The polyolefin resin forming the network structure layer and the polyolefin resin forming the polyolefin resin layer may be of the same type or different types.

The thickness of the polyolefin-based resin layer inside the network structure layer is preferably 35 μm or more, more preferably 45 μm or more. When the thickness of the inner polyolefin resin layer is at least the lower limit of the above range, sufficient sealing strength is obtained, peeling of the sealing portion and tearing from the inner edge of the sealing portion are less likely to occur, and the pressure resistance is improved. There is no particular upper limit to the thickness of the inner polyolefin resin layer, but if it is too thick, the cost will increase, so 60 μm or less is preferable.

The thickness of the polyolefin-based resin layer outside the network structure layer is preferably 10 to 30 μm, more preferably 15 to 25 μm. When the thickness of the outer polyolefin resin layer is equal to or greater than the lower limit of the above range, sufficient sealing strength can be obtained with the sealant layer of the sheet material constituting the outer bag 20, and the thickness of the outer polyolefin resin layer becomes thicker. When it is not more than the upper limit of the above range, sufficient sealing strength can be obtained without excessively increasing the sealing temperature.

The tensile strength of the first laminated body 11 is preferably 60.0 N or more, more preferably 70.0 N or more in both the vertical direction: MD (Machine Direction) and the horizontal direction: TD (Transverse Direction). When the tensile strength of the first laminated body 11 is at least the lower limit value, the first laminated body 11 is less likely to break even if the internal pressure increases, and the inner bag 10 can be prevented from breaking. As a result, the pressure resistance strength is increased, and the bag breakage of the packaging bag 1 can be suppressed. The higher the tensile strength of the first laminated body 11, the better, and the upper limit is not particularly limited.
The tensile strength is measured according to JIS K7127 under the conditions of the width of the test piece: 15 mm, the test speed: 300 mm / min, and the distance between chucks: 50 mm.

The tensile elongation of the first laminated body 11 is preferably 40% or less, more preferably 30% or less for both MD and TD. When the tensile elongation of the first laminated body 11 is not more than the upper limit value, the first laminated body 11 is difficult to extend even if the internal pressure is increased, and the expansion of the inner bag 10 can be suppressed. As a result, the outer bag 20 on the outer side of the inner bag 10 can be prevented from being broken due to expansion, so that the pressure resistance is increased and the bag 1 can be suppressed from being broken. The lower the tensile elongation of the first laminated body 11, the better, and the lower limit is not particularly limited.
The tensile elongation is measured according to JIS K7127 under the conditions of the width of the test piece: 15 mm, the test speed: 300 mm / min, and the distance between chucks: 50 mm.
When both the tensile strength and the tensile elongation of the first laminated body 11 are within the above ranges, the first laminated body 11 is difficult to extend and break even if the internal pressure is increased, so that expansion and tearing of the inner bag 10 are suppressed. can do. The packaging bag 1 using the inner bag 10 can obtain a compressive strength of 0.3 MPa or more that can withstand even when the content is a carbon dioxide gas-containing beverage in an environment of 20 ° C.
There are various types of fiber orthogonal laminated non-woven fabrics, such as those having the same thickness or different thicknesses of the vertical web and the horizontal web, and the tensile strength and tensile elongation have the same values in MD and TD. And there are different things.

The method of laminating each layer in the first laminated body is not particularly limited, and for example, a known method such as an extrusion laminating method, a thermal laminating method, or a dry laminating method can be adopted. Among them, the extrusion laminating method is preferable because it reduces the influence of the unevenness of the surface of the network structure layer on the surface of the first laminated body and makes it easy to produce the first laminated body having a flat surface. Further, the molten resin of the extrusion laminating method flows into the network structure layer so that the unevenness on the surface of the network structure layer becomes flat and laminated, so that the adhesive strength between the network structure layer and the inner and outer polyolefin resin layers becomes stronger. From the viewpoint, the extrusion laminating method is preferable.

(Outer bag)
As the sheet material constituting the pair of flat surface portions 21 and 22 and the bottom portion 23 of the outer bag 20, a material having at least a sealant layer in the inner layer can be used. The sheet material constituting the outer bag 20 may have a single-layer structure consisting of only a sealant layer, or may be a second laminated body having a multi-layer structure having a sealant layer in the inner layer.

Examples of the layer provided outside the sealant layer of the second laminated body include a base material layer having excellent printability and strength, gas barrier property, mechanical toughness, bending resistance, puncture resistance, and impact resistance. Examples thereof include functional layers having required functions such as abrasion resistance, cold resistance, heat resistance, and chemical resistance.

As the second laminated body, a laminated body having a gas barrier layer provided on the outside of the sealant layer is preferable from the viewpoint that it can be suitably used for filling a carbonated beverage, and a functional layer is provided between the sealant layer and the base material layer to be the outer layer. A laminate provided with a gas barrier layer is more preferable. The outer layer of the second laminated body is the outermost layer of the packaging bag 1.

The material for forming the sealant layer is not particularly limited, and for example, polyethylene resin such as low density polyethylene (LDPE), medium density polyethylene, high density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene resin and the like. Examples thereof include the above-mentioned polyolefin resin, a mixed resin thereof, an ionomer resin, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, an ethylene-methyl acrylate copolymer, and an ethylene-methacrylic acid copolymer. As the material for forming the sealant layer, one type may be used alone, or two or more types may be used in combination. Further, the sealant layer may be a single layer or a multilayer layer.

The thickness of the sealant layer of each sheet material of the outer bag 20 is preferably 60 to 180 μm, more preferably 80 to 150 μm. If the thickness of the sealant layer is equal to or greater than the lower limit of the above range, either the sealed portion sealed with the inner bag 10 sandwiched between the outer bags 20 or the sealed portion sealed only with the outer bag 20. However, sufficient seal strength can be obtained, and tearing from peeling of the seal portion is unlikely to occur, so that high pressure resistance that can suppress bag breakage can be easily obtained. When the thickness of the sealant layer is not more than the upper limit of the above range, sealing at a low temperature is possible, so that the production efficiency can be improved.

The base material layer is not particularly limited, and examples thereof include a resin film, paper, a non-woven fabric, and the like, and a resin film is preferable. As the resin film, an unstretched film may be used, or a stretched film may be used. In terms of printability and strength, a stretched film stretched uniaxially or biaxially is preferable.

The material of the resin film is not particularly limited, and is, for example, polyester resin (polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc.), polyamide resin, polypropylene resin, polycarbonate resin, polyacetal resin. And so on. As the material of the resin film, one type may be used alone, or two or more types may be used in combination. The thickness of the resin film used for the base material layer is not particularly limited, but is preferably about 9 to 20 μm.

The gas barrier layer is not particularly limited, and for example, a metal foil (aluminum foil, magnesium foil, etc.) or a vapor-deposited film having a metal (aluminum, magnesium) or metal oxide (aluminum oxide, silicon oxide, etc.) vapor-deposited film. Examples thereof include a PVDC coated film having a polyvinylidene fluoride (PVDC) coated layer, an ethylene-vinyl alcohol copolymer (EVOH) film, and the like. As the base film of the vapor-deposited film or the PVDC-coated film, for example, the resin film exemplified as the base layer can be used.

The functional layer other than the gas barrier layer is not particularly limited, and a film having appropriately necessary functions such as impact resistance and tearability may be used. For example, polyethylene terephthalate, polyamide resin, polyvinyl chloride, polycarbonate resin, polyvinyl may be used. Examples thereof include films such as alcohol and ethylene-vinyl acetate copolymer saken, non-woven films having heat insulating properties, and foamed films. The thickness of the metal foil used for the functional layer is not particularly limited, but is preferably about 7 to 15 μm. The thickness of the resin film used for the functional layer is not particularly limited, but is preferably about 9 to 20 μm as in the base material layer.
The functional layer included in the second laminated body may be one type or two or more types.

The method of bonding each layer in the second laminated body is not particularly limited, and for example, the same method as the method exemplified as the method of bonding each layer in the first laminated body can be exemplified. Of these, the dry laminating method is preferable from the viewpoint of obtaining strong adhesive strength. Examples of the adhesive used in the dry laminating method include urethane-based two-component curable adhesives.

In the packaging bag 1, the inner bag 10 is less likely to extend because the first laminated body 11 has a mesh structure layer, and is less likely to expand or break even when the internal pressure increases. On the other hand, only the inner bag 10 made of the first laminated body 11 having a mesh structure layer cannot secure sufficient sealing strength by heat welding, and when the internal pressure filled with carbonated drinks or the like becomes high, the seal peels off and the bag breaks. Cheap. However, in the inner bag 10, a polyolefin resin layer is provided on both sides of the network structure layer, sandwiched between the sealant layers of the outer bag 20, and heat-welded together with them, whereby sufficient sealing strength can be ensured. From these facts, even if the inner bag 10 and the outer bag 20 are filled with carbonated drinks and the like and the internal pressure is increased, the inner bag 10 and the outer bag 20 are less likely to expand and tear, and the sealed portion is less likely to be peeled off, so that the bag 1 can be prevented from breaking. ..

The sealing strength of the upper sealing portion 2 and the side sealing portion 3, which are the sealing portions where the inner bag 10 and the outer bag 20 overlap, is preferably 100 N / 15 mm or more, and more preferably 110 N / 15 mm or more. When the sealing strength of the sealing portion is equal to or higher than the lower limit of the above range, the pressure resistance strength becomes high, and the tearing of the packaging bag due to the peeling of the sealing portion can be suppressed.
The upper limit of the seal strength of the upper seal portion 2 and the side seal portion 3, which are the seal portions where the inner bag 10 and the outer bag 20 overlap, is preferably 120 N / 15 mm. When the sealing strength of the sealing portion is not more than the upper limit of the above range, it is possible to suppress bag breakage due to tearing from the inner edge of the sealing portion. If the sealing temperature is raised in order to increase the sealing strength of the sealing portion, the base material layer of the second laminate forming the outer bag 20 may also melt, and the base material layer may be torn from the inner edge of the sealing portion. There is. Further, if the sealing temperature is raised in order to increase the sealing strength of the sealing portion, the resin of the network structure layer is melted, the network structure is destroyed, and the tensile strength and tensile elongation near the inner edge of the sealing portion are lowered. Therefore, it may not be able to withstand the expansion of the inner bag due to pressurization, and the bag may break. Therefore, a sealing temperature having a sealing strength of 100 to 120 N / 15 mm is appropriate.

The sealing strength of the bottom sealing portion 4, which is the sealing portion of only the outer bag 20, is preferably 100 N / 15 mm or more, more preferably 125 N / 15 mm or more. When the sealing strength of the sealing portion is equal to or higher than the lower limit of the above range, the pressure resistance strength becomes high, and the tearing of the packaging bag due to the peeling of the sealing portion can be suppressed.
The upper limit of the sealing strength of the sealing portion (bottom sealing portion 4) of only the outer bag 20 is not particularly limited.
The seal strength is measured in accordance with JIS K7127 under the conditions of the width of the test piece: 15 mm, the test speed: 300 mm / min, and the distance between chucks: 50 mm.

In the packaging bag 1, the inner bag 10 is not sandwiched between the outer bags 20 in the bottom seal portion 4, and the bottom 12 of the inner bag 10 is not fixed to the bottom seal portion 4. When the internal pressure increases, the inner bag 10 expands, but the inner bag 10 does not easily expand, and the bottom 12 of the inner bag 10 is not fixed to the bottom seal portion 4, so that the bottom 23 of the outer bag 20 is deformed from the inner bag 10. It is possible to maintain independence without following.

The dimensions of the packaging bag 1 are not particularly limited and can be set as appropriate.
As shown in FIG. 6, when the contents are filled and the internal pressure increases and the inner bag 10 and the outer bag 20 expand, the first side of the inner flat portion 21 side and the flat portion 22 side of the side seal portion 3 The opening angle θ of the laminated body 11 approaches 180 degrees as the width dimension and the internal volume of the packaging bag 1 increase. The closer the angle θ is to 180 degrees, the greater the force that peels off the side seal portion 3 from the inside. Therefore, it is preferable to set the width dimension and the internal volume of the packaging bag 1 in consideration of the angle θ when the contents are filled and the internal pressure is increased.
When the packaging bag 1 is capable of withstanding an internal pressure of about 0.4 MPa in an environment of 20 ° C., for example, the width dimension of approximately four sides can be 80 mm or less, the height dimension can be 140 mm or less, and the internal volume can be 160 mL or less.

(Spout)
In the packaging bag 1, the upper seal portion 2 is provided with a spout 30 for pouring out the contents contained in the inner bag 10 to the outside or for drinking the contents. A cap 31 is provided at the upper end of the spout 30 so as to be screwed into the spout 30 to close the opening of the spout 30.

For example, the cap 31 can be attached to the spout 30 by forming a male screw on the outer peripheral surface of the spout 30 and forming a female screw to be screwed into the male screw on the inner peripheral surface of the cap 13.
In addition to the screw type that has male and female screws and can be resealed, the spout and cap are, for example, a plug type that attaches the cap to the spout by tapping, and a pull ring or the like is formed on the cap. Then, by pulling up the cap from the spout, various shapes such as a pull tab type that removes the sealing film of the spout and opens the cap can be used.

The spout 30 has at least a tubular portion and a joint portion between the inner bag 10 of the packaging bag 1 and may be formed of a single material or may be formed of a multilayer structure composed of various resin layers. May be good.
The spout 30 preferably has a gas barrier property. The spout 30 having a gas barrier property is not particularly limited, and examples thereof include those having a gas barrier layer such as a metal foil layer and an EVOH layer inside the tubular portion.

Of the spouts 30, at least the resin forming the joint portion to be joined to the first laminated body 11 of the inner bag 10 can be joined to the inner bag 10 by heat sealing, so that the innermost layer of the first laminated body 11 is formed. It is preferable that the resin is made of the same type of polyolefin resin as the polyolefin resin forming the above.

The material of the cap 31 is not particularly limited, and for example, the same synthetic resin as the material of the spout 30 can be adopted. The cap 31 preferably has a gas barrier property, such as providing a film provided with a gas barrier layer such as a metal foil layer or an EVOH layer at a position where the opening of the spout 30 in the cap 31 is closed.

The manufacturing method of the packaging bag 1 is not particularly limited. For example, the first laminated body 11 and the sheet material forming the bottom portion 23 are folded back and arranged between the sheet materials forming the pair of flat surface portions 21 and 22, and the first laminated body 11 is not included by heat sealing. The bottom seal portion 4 is formed, and the side seal portions 3 on both sides on which the first laminated body 11 is overlapped are formed. Next, the spout 30 is inserted between the overlapped upper edge portions 11a and 11a of the first laminated body 11, and the spout 30 is liquid-tightly heat-sealed so as to sandwich the spout 30 to form the upper sealing portion 2, and the packaging bag is formed. 1 is manufactured.

[Content filler]
The content filling material of the present invention is one in which the contents are filled in the packaging bag of the present invention.
The contents are not particularly limited, and examples thereof include liquid beverages such as beer, low-malt beer, sparkling wine, and carbon dioxide-containing beverages (carbonated beverages) such as cola, jelly, and soup. The present invention is particularly effective when the content is a carbon dioxide gas-containing beverage because the packaging bag has excellent compressive strength. When the content is a carbon dioxide-containing beverage, the packaging bag is required to have a compressive strength of 0.3 MPa or more in an environment of 20 ° C.

As described above, the packaging bag of the present invention has a double structure having an inner bag and an outer bag, and is substantially square. The inner bag made of the first laminated body including the mesh structure layer is folded back and not fixed to the outer bag at at least one of the peripheral portions on substantially four sides, and is sealed only by the outer bag. Further, on the other peripheral edges of the substantially four sides, the inner bag and the outer bag are fixed and sealed with the inner bag sandwiched between the outer bags. Since the first laminated body has a mesh structure layer, the inner bag is less likely to expand or break, and the inner bag is sandwiched between the outer bags and sealed together with the outer bag at the other peripheral edges, so that sufficient sealing is possible. Strength is also ensured, and bag breakage due to seal peeling can be suppressed. Therefore, the packaging bag of the present invention can suppress bag breakage even when the internal pressure is high by filling a carbonated drink or the like. Further, in the packaging bag of the present invention, the contents can be drunk directly from the spout by providing the spout.

The packaging bag of the present invention is not limited to the above-mentioned packaging bag 1.
For example, it is better to have a gusset at the bottom of the outer bag, but it does not have a gusset at the bottom of the outer bag, and the first laminated body of the inner bag also has a W-shaped cross section in the vertical direction. It may not be folded back, but may only be folded back into a V-shaped cross section. Further, the pair of flat surface portions and the bottom portion forming the outer bag may be formed by folding a single sheet material. In this case, the outer bag is more self-supporting if it has a bottom seal portion, but it may not have a bottom seal portion.
The packaging bag of the present invention may be a packaging bag without a spout. In the present invention, the outer bag does not have to be a standing pouch.
In the packaging bag of the present invention, a tubular film is used for the first laminated body constituting the inner bag, so that the inner bag is folded back and fixed to the outer bag at the peripheral edges of two of the four sides. However, the peripheral portions of the other two of the four sides may be fixed with the inner bag sandwiched between the outer bags.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following description.

[Seal strength]
In the packaging bag manufactured in each example, the part above the bottom of the side seal part is sealed under the conditions of JIS Z0238, test piece width: 15 mm, test speed: 300 mm / min, and chuck distance: 50 mm. The intensity was measured.

[Tensile strength]
The tensile strength of the MD and TD of the first laminated body produced in each example, the laminated body corresponding thereto, and the film was measured. The tensile strength was measured according to JIS K7127 under the conditions of the width of the test piece: 15 mm, the test speed: 300 mm / min, and the distance between chucks: 50 mm.

[Tensile elongation]
The tensile elongations of the MD and TD of the first laminated body produced in each example, or the corresponding laminated body and the film were measured. The tensile elongation was measured according to JIS K7127 under the conditions of the width of the test piece: 15 mm, the test speed: 300 mm / min, and the distance between chucks: 50 mm.

[Compressive strength]
A machine equipped with a pressure sensor attached to a handmade manual pump gradually applies pressure to the inside of the packaging bag of each example in a 20 ° C environment, and the packaging bag is peeled off or broken when the side seal is peeled off. The pressure applied to the inside of the was measured and used as the withstand voltage strength. In addition, although the side seal part did not peel off or the bag was torn, when the aluminum foil was torn due to the film stretching and the aluminum foil was torn and the bag did not function as a packaging bag, it was added to the inside of the packaging bag at that time. The pressure was measured and used as the pressure resistance strength. When the withstand voltage reached 0.4 MPa, the pressurization was stopped at that time.

[Appearance of packaging bag]
The appearance of the packaging bag whose compressive strength was measured was observed and evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: When a pressure of 0.3 MPa was applied, the side seals were not peeled off, the inner bag and outer bag were torn, and the aluminum foil was not torn.
B: Higher pressure resistance compared to the packaging bag containing only the outer bag without using the first laminated body (Comparative Example 3 described later), but the side seal portion was peeled off before the pressure of 0.3 MPa was applied. Or something that has a broken bag.
C: A product having a withstand voltage equivalent to that of a packaging bag containing only an outer bag (Comparative Example 3 described later) without using the first laminated body.

[Example 1]
A packaging bag having the same embodiment as the packaging bag 1 illustrated in FIGS. 1 to 5 was manufactured.
As the second laminate forming the outer bag, a biaxially stretched polyethylene terephthalate film (PET, thickness 12 μm) as a base material layer, an aluminum foil (AL, thickness 9 μm) as a functional layer, and biaxially stretched as a functional layer from the outside. A nylon film (ONY, thickness 15 μm) and a laminate in which a linear low-density polyethylene film (LLDPE, thickness 120 μm) was sequentially laminated as a sealant layer were used. The second laminated body was laminated by a dry laminating method using a urethane-based two-component curable adhesive as an adhesive. As the first laminated body forming the inner bag, polyethylene resin (outside, thickness 20 μm), fiber orthogonal laminated non-woven fabric (mesh structure layer, manufactured by ENEOS Technomaterial, “Wariff EX24”, grain 47 g / m ² ), from the outside, And a laminated body in which polyethylene resin (inside, thickness 50 μm) was laminated in this order was used. The first laminated body was laminated by the extrusion laminating method. As the spout, a polyethylene resin spout was used.

The second laminated body forming the bottom portion of the outer bag and the first laminated body were arranged between the second laminated bodies forming a pair of flat surface portions, respectively. The second laminated body forming the bottom portion of the outer bag was arranged on the bottom side of the second laminated body forming a pair of flat surface portions in a state of being folded upward in a valley fold. The first laminated body was folded in half in the vertical direction, and the bottom of the first laminated body was further folded into a valley fold, and the bottom of the first laminated body was arranged along the inside of the bottom of the outer bag. By heat sealing at 180 ° C. for 3 seconds, a side sealing portion 3 in which the second laminated body and the first laminated body overlap on both sides in the width direction and a bottom sealing portion 4 of only the second laminated body are formed, and the upper portion is opened. Formed a double bag. Next, a spout is inserted between the overlapped upper edges of the first laminated body, and the spout is liquid-tightly sealed by heat sealing at 200 ° C. for 4 seconds to form the upper sealing portion 2 to manufacture a packaging bag. did. The dimensions of the flat surface of the outer bag were 80 mm in width × 140 mm in height, the height of the folded portion of the valley fold at the bottom was 25 mm, and the internal volume was 160 mL. The vertical direction of the side seal portion of the manufactured packaging bag coincides with the MD of the first laminated body and the second laminated body.

[Example 2]
A packaging bag was manufactured in the same manner as in Example 1 except that the polyethylene resin inside the first laminated body forming the inner bag was changed to a thickness of 40 μm.

[Example 3]
The same as in Example 2 except that the fiber orthogonal laminated non-woven fabric of the mesh structure layer of the first laminated body forming the inner bag was changed to "Wariff HSP (T)" manufactured by ENEOS Technomaterial and a grain of 37 g / m ² . Manufactured packaging bags.

[Example 4]
The packaging bag was prepared in the same manner as in Example 2 except that the fiber orthogonal laminated non-woven fabric of the mesh structure layer of the first laminated body forming the inner bag was changed to ENEOS Technomaterial, "Wariff S", and a grain of 24 g / m ² . Manufactured.

[Comparative Example 1]
In the side seal part of the outer bag, the side edges of the inner bag are not sandwiched between the side edges of the outer bag, and the side edges of the inner bag and the side edges of the outer bag are separately heat-sealed. A packaging bag was manufactured in the same manner as in Example 1 except that the bags were joined together.
The seal strength of the side seal portion in Comparative Example 1 describes the seal strength of the outer bag and the seal strength of the inner bag, respectively.

[Comparative Example 2]
Instead of the first laminated body forming the inner bag, two linear low-density polyethylene films having a thickness of 100 μm and having no network structure layer were used in a state where they were not laminated to each other to bring them closer to the thickness of the first laminated body. A packaging bag was produced in the same manner as in Example 1 except that the one used was used. The thickness of the first laminated body in the packaging bag of Example 1 was 180 μm to 200 μm.
The values of "tensile strength and tensile elongation of the first laminated body" in Comparative Example 2 are obtained by stacking two linear low-density polyethylene films having a thickness of 100 μm in a state where they are not laminated with each other to obtain tensile strength and tensile elongation. It was measured.

[Comparative Example 3]
A packaging bag was manufactured in the same manner as in Example 1 except that the packaging bag was only an outer bag without an inner bag.

Table 1 shows the measurement results of the tensile strength, tensile elongation, sealing strength of the side seal portion in the packaging bag, outer bag or inner bag, and pressure resistance strength of the first laminated body or its equivalent used in each example.

As shown in Table 1, an example in which a first laminated body containing a mesh structure layer was used in the inner bag, and the peripheral edge of the inner bag was sandwiched between the sealant layers of the outer bag in the upper seal portion and the side seal portion and heat-sealed. In Nos. 1, 2 and 3, the seal strength of the side seal portion is high, and the tensile strength and tensile elongation of the first laminated body are excellent, so that the pressure resistance strength is excellent. No bag breakage such as tearing of the inner bag and outer bag occurred.
Example 1 in which the thickness of the polyethylene resin inside the first laminated body is 50 μm is compared with Example 2 in which the thickness of the polyethylene resin inside is 40 μm, and in particular, the tensile strength of the TD and the sealing strength of the side seal portion. I was able to apply higher pressure.
Example 2 of the fiber orthogonal laminated non-woven fabric of the mesh structure layer of the first laminated body has a texture of 47 g / m ² as compared with Example 3 having a texture of 37 g / m ² , and the value of the tensile strength of TD is excellent, but the tensile strength is high. The elongation value was inferior and the pressure resistance strength was the same. Similarly, when 0.35 MPa was applied, the seal was partially peeled off at the boundary between the portion where the bottom of the side seal portion was present and the portion where the bottom was not present. Later, the film broke and broke due to rupture at that part.
Further, Example 4 of the fiber orthogonal laminated non-woven fabric of the mesh structure layer of the first laminated body has a grain size of 24 g / m ² is compared with Example 2 having a grain size of 47 g / m ² and Example 3 having a grain size of 37 g / m ² . In comparison, the tensile strength, tensile elongation, and heat seal strength were all inferior, and when a pressure of 0.18 MPa was applied, the seal was peeled off halfway at the boundary between the portion where the bottom of the side seal portion was present and the portion where the bottom was not present. Later, the film broke and broke due to rupture at that part.

When the tensile strength, tensile elongation, and sealing strength of the first laminated body are not sufficient, when pressure is applied to the inside of the packaging bag, the boundary between the part where the bottom of the side sealing part exists and the part where it does not exist (Fig.) In the region indicated by reference numeral 40 in 1), bag breakage due to seal peeling or bag breakage due to bursting at that portion after the seal was peeled halfway was likely to occur.
Since the direction of the force acting when peeling off the side seal portion is the direction orthogonal to the extending direction of the side seal portion, the MD and TD of the film having excellent tensile strength and tensile elongation. It is considered that the bag breakage from the boundary between the portion where the bottom portion exists and the portion where the bottom portion does not exist in the side seal portion can be further suppressed by matching the direction with the extending direction of the side seal portion. .. Further, it is considered that the bag breakage can be further suppressed by providing a partial sealing portion at this boundary.

On the other hand, in Comparative Example 1 in which the inner bag and the outer bag are separately sealed by the side seal portion, the seal strength of the side seal portion of the inner bag heat-sealed only by the first laminated body is low, and the side seal portion is peeled off. have done. In addition, the second laminated body of the outer bag stretched and the film broke due to rupture at the flat surface portion, and the bag broke.
Further, in Comparative Example 2 in which the laminated body of the inner bag does not include the mesh structure layer, the inner bag also expands due to the increase in the internal pressure and the laminated body of the inner bag expands, and the second laminated body of the outer bag also expands accordingly. The bag broke due to the film tearing due to the rupture on the flat surface. Even in Comparative Example 3 in which only the outer bag was used, the pressure resistance was low, the outer bag expanded due to the increase in the internal pressure, the laminated body of the outer bag stretched, and the film was torn and broke due to the rupture at the flat surface portion.

1 ... Packaging bag, 2 ... Top seal part, 3 ... Side seal part, 4 ... Bottom seal part, 10 ... Inner bag, 11 ... First laminated body, 11a ... Upper edge part, 11b ... Side edge part, 12 ... Bottom, 20 ... outer bag, 21 ... flat surface, 21a ... upper edge, 21b ... side edge, 21c ... lower edge, 22 ... flat surface, 22a ... upper edge, 22b ... side edge, 22c ... bottom Edge, 23 ... bottom, 23a ... folding line, 23b, 23c ... side edge, 23d, 23e ... lower edge, 30 ... spout.

Claims (7)

It has a double structure with an inner bag and an outer bag, and is a packaging bag consisting of approximately four sides.
The inner bag is composed of a first laminated body including a network structure layer made of a polyolefin resin and polyolefin resin layers provided on both sides of the network structure layer.
The inner bag is folded back and is not fixed to the outer bag at at least one peripheral portion of the substantially four sides.
The other peripheral edge portion of the substantially four sides is a packaging bag in which the inner bag is fixed while being sandwiched between the outer bags. At the peripheral edge of one of the substantially four sides, the inner bag is folded back and is not fixed to the outer bag.
The packaging bag according to claim 1, wherein the peripheral portions on the other three sides of the substantially four sides are fixed with the inner bag sandwiched between the outer bags. The packaging bag according to claim 1 or 2, wherein the outer bag comprises a second laminated body including a sealant layer and a gas barrier layer provided on the outside of the sealant layer. The packaging bag according to any one of claims 1 to 3, further comprising a spout. The packaging bag according to any one of claims 1 to 4, wherein the outer bag has a gusset at the bottom. A content filler in which the packaging bag according to any one of claims 1 to 5 is filled with the contents. The content filler according to claim 6, wherein the content is a carbon dioxide gas-containing beverage.

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