JPH09314735A - High barrier packaging material and bag body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve shielding, gas barrier properties, physical strength, and flexural resistance by laminating an oriented nylon film, metal foil, a coextruded film consisting of two linear low density polyethylene layers and a nylon layer sandwiched between them, and a linear low density polyethylene film in sequence. SOLUTION: A high barrier packaging material 101 is formed by laminating an oriented nylon film 1, metal foil 2, a prescribed coextruded film 3, and a linear low density polyethylene film or a low density polyethylene film 4 in this order. The film 3 is composed of two linear low density polyethylene layers or low density polyethylene layers 3a, 3c and a nylon layer 3b which is sandwiched between them. The metal foil 2 layer gives the packaging material 101 almost complete shielding effect and high gas barrier properties. Since the foil 2 is sandwiched between the two films 1, 3 having high physical strength and flexural resistance for reinforcement, impact resistance and pinhole resistance improve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-barrier packaging material excellent in light-shielding property and gas barrier property, and a bag body formed by using such a packaging material. More specifically, it has extremely high light-shielding property and gas barrier property. The present invention relates to a bag having good impact resistance and good pinhole resistance, and a packaging material suitable as a material for forming such a bag.

The bag provided by the present invention is preferably used as a bag for filling a relatively large amount of fluid (liquid, powder, etc.).

[0003]

2. Description of the Related Art An inner bag for a bag-in-box is usually filled with a relatively large amount of liquid. Therefore, the inner bag is required to have excellent durability so as to prevent bag breakage and pinholes even when its own weight after filling is considerably heavy.

That is, a physical impact such as a drop impact applied to a large-capacity bag is significantly larger than that of a small-capacity having a small self-weight, so that the packaging material forming the bag is easily broken. For this reason, when a large-capacity bag is manufactured with a packaging material with poor physical strength such as impact resistance, impact stress is mainly applied to the seam of the seal part of the bag (the boundary line between the seal part and the non-seal part). Are concentrated, and bag breaks and pinholes occur in the vicinity. Also, since the large-capacity bag body has a large bending stress due to the deformation of the bag (that is, the occurrence of wrinkles) due to its weight,
Pinholes are likely to occur over the entire bag.

As inner bags for bag-in-boxes, at present, several kinds of inner bags made of a coextruded film having a gas barrier layer of an EVOH (ethylene-vinyl alcohol copolymer) film or other packaging materials are used. Has been put to practical use. These inner bags have fairly good impact resistance and pinhole resistance. However, all of them are transparent or translucent and do not have a light shielding property.

[0006] The inner bag for the bag-in-box is usually stored in an outer box having a light-shielding property, so that it is rarely exposed to light, but nevertheless, when the contents are filled or the outer box is stripped off. When using the inner bag, the inner bag is exposed to light. Also, as an outer box of the bag in box,
Although it is possible to use a foldable box that is repeatedly reused, such as a plastic foldable container, the majority of foldable outer boxes do not provide sufficient light shielding. Therefore, the inner bag for bag-in-box is
It is desirable that it itself has a light shielding property. In particular, in the case of filling a content that is altered by irradiation of light rays, the inner bag itself is strongly required to have a light-shielding property.

Also, the inner bag for the bag-in-box,
Along with durability, good gas barrier properties are required so that the contents are not altered by gases such as oxygen and water vapor. However, depending on the contents to be filled, the gas barrier properties of the inner bag currently in practical use may not be sufficient. Therefore, it is desired to further improve the gas barrier properties of the inner bag.

By the way, various composite films having an aluminum foil layer are known as a packaging material having an extremely excellent light-shielding property and gas barrier property. When a relatively small amount of liquid is filled, the stretched nylon film (ON) as the outermost layer, the aluminum foil (Al foil) as the first intermediate layer, the stretched nylon film as the second intermediate layer, and A bag formed of a composite film in which a linear low density polyethylene film (LLDPE) as the innermost layer is laminated in this order is used.

[0009]

Therefore, the present inventors have developed an inner bag for a bag-in-box with the above-mentioned composite film (ON / Al foil / ON / LLDPE) used for a small capacity liquid bag. I tried to manufacture it, but there were many bags and pinholes. From this result, it was found that the above composite film had no problem in the case of a small capacity, but could not bear the self-weight after filling when the capacity was large. Also, the cause is
Due to the high rigidity and low elongation of the aluminum foil layer,
It was considered that the packaging material could not absorb the large impact stress and bending stress when filling a large volume. The present invention has been accomplished in view of such circumstances.

A first object of the present invention is to provide a packaging material which has an extremely high light-shielding property and gas barrier property as well as excellent physical strength and bending resistance. A second object of the present invention is a bag body having extremely high light-shielding property and gas barrier property and also having good impact resistance and pinhole resistance, and a packaging material suitable as a material for forming such bag body. To provide.

A third object of the present invention is a bag having excellent impact resistance and pinhole resistance despite having a metal foil layer such as aluminum foil, and such a bag. It is to provide a packaging material suitable as a body forming material.

A fourth object of the present invention is to provide a large-capacity bag having extremely high light-shielding property and gas barrier property as well as good impact resistance and pinhole resistance, especially for bag-in-box. It is to provide a bag body suitable as an inner bag and a packaging material suitable as a material for forming such a bag body.

[0013]

In order to achieve the above object, the present invention provides a high barrier packaging material comprising a composite film in which the following first to fourth layers are laminated in this order. To do. First layer: stretched nylon film, second layer: metal foil, third layer: coextruded film having two linear low-density polyethylene layers or low-density polyethylene layers, and a nylon layer sandwiched therebetween. 4th layer: Linear low-density polyethylene film or low-density polyethylene film.

Preferably, as the above-mentioned metal foil, an embossed metal foil or alloy No. An aluminum foil made of 8021 material is used. Further, as a bag body using the above-mentioned high barrier property packaging material, the wall surface of the bag body is formed of one packaging material or two or more packaging materials in which respective contact surfaces are slidably stacked. Provided is a bag body characterized in that at least one of the packaging materials constituting the wall surface is the above-mentioned high barrier packaging material.

Since the packaging material of the present invention has the metal foil layer, it has almost perfect light shielding property and extremely high gas barrier property. Further, in the present invention, the metal foil layer is reinforced by sandwiching it between two films having excellent physical strength and bending resistance to enhance the impact resistance and pinhole resistance of the packaging material. The metal foil layer is strongly reinforced by laminating a coextrusion film having two linear low density polyethylene layers or a low density polyethylene layer and a nylon layer sandwiched between the two layers, adjacent to the metal foil layer. ing.

Therefore, the bag manufactured by using the packaging material of the present invention has extremely high light-shielding property and gas barrier property, and even when it is made into a large-capacity bag, no bag breakage or pinhole is generated. It has both sufficient impact resistance and bending resistance. When the packaging material of the present invention and another packaging material are superposed on each other to form a bag having a multi-wall structure, an external force applied to the packaging material of the present invention is added due to the cushioning action of the superposed packaging materials. Since it is relieved, bag breakage and pinholes are less likely to occur.

Also, the metal foil or alloy No. 1 having the above-mentioned metal foil layer embossed. When the aluminum foil layer is made of 8021 material, the packaging material has particularly high impact resistance and pinhole resistance.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. FIG. 1 schematically shows a cross section of the high barrier packaging material (101) of the present invention. The high barrier packaging material of the present invention comprises a stretched nylon film (ON) 1 as a first layer, a metal foil 2 as a second layer, a predetermined coextruded film 3 as a third layer, and a linear low density as a fourth layer. The polyethylene film (LLDPE) or the low density polyethylene film (LDPE) 4 is a composite film having a structure laminated in this order. As the coextrusion film 3, two linear low density polyethylene layers (L
LDPE) or low density polyethylene layer (LDPE) 3
A coextruded film having a, 3c and a nylon layer 3b sandwiched therebetween is used. The first to fourth layers
Each layer up to the layer can be adhered using an adhesive 5 as necessary.

The stretched nylon film 1 as the first layer is
Usually, it is the outermost layer of the package in order to secure the surface strength of the package. Here, the material of nylon is not particularly limited, and either a uniaxially stretched film or a biaxially stretched film may be used. The thickness of the stretched nylon film is usually 12 to 25 μm, and the lower limit is preferably 15 μm.
m or more. If the thickness is less than 12 μm, the pinhole resistance may be insufficient, while if it exceeds 25 μm, the stiffness tends to be too strong and the cost is high.

The metal foil 2, which is the second layer, is important for providing the packaging material with almost perfect light shielding property and extremely high gas barrier property. As the metal foil, for example, aluminum foil (including aluminum alloy foil) is used. The thickness of the metal foil is usually 6.5 to 12 μm, and preferably the lower limit is 7 μm or more or the upper limit is 9 μm or less. If the thickness is less than 6.5 μm, the number of pinholes originally possessed by the metal foil itself is too large, which is disadvantageous to the gas barrier property. easy. Further, from the viewpoint of ensuring flammability at the time of disposal, the thickness of the metal foil is preferably 12 μm or less, and particularly preferably 9 μm or less.
Among the metal foils, the embossed metal foil and the alloy No. An aluminum foil made of 8021 material can be exemplified.

When the metal foil in the packaging material is an embossed metal foil, the impact resistance of the bag produced using this is improved, and the bag is broken or pinholes near the seam of the seal portion. Is less likely to occur. The reason is estimated as follows. That is, as shown in FIG. 2 a, the stress P generated by an impact such as a drop impact applied to the bag body is concentrated on the joint 8 of the seal portion 6 and the non-seal portion 7, and is transmitted on the joint 8. Therefore, the packaging material forming the bag is likely to be torn near the joint between the sealed portion and the non-sealed portion. In particular, when the packaging material includes a layer of metal foil, the rigidity of this layer is high and it is difficult to stretch, so that the packaging material is more likely to be torn. On the other hand, when the metal foil is embossed, the boundary line (step portion) 10 between the convex portion 9 and the concave portion formed on the metal foil 10 as shown in FIG. 2B.
Intersect with the seam 8 of the seal portion, and a part of the stress P transmitted on the seam 8 is a boundary line 10 between the convex portion and the concave portion.
Transmitted to the top. As a result, it is estimated that the impact stress applied to the metal foil layer, which is the most problematic, is not concentrated in one place but dispersed, and the packaging material is less likely to be broken.

Alloy N is used as the metal foil in the packaging material.
o. When the aluminum foil made of 8021 material is used, impact resistance and flex resistance of the bag body are improved, and the bag is ruptured near the seam of the seal portion or the entire bag body including the seam of the seal portion. Pinholes are less likely to occur. Here, alloy No. The 8021 material is an aluminum alloy containing a relatively large amount of iron element (Fe), and has a chemical composition shown in Table 1 below or a chemical composition similar thereto.

[0023]

[Table 1] Alloy No. The aluminum foil made of 8021 material has crystal grains made extremely fine by optimizing the additive elements and the manufacturing process, and fine intermetallic compounds are uniformly distributed inside the aluminum foil. This aluminum foil is superior in physical strength to the conventional aluminum foil made of 1N30 material and has the property of being easily stretched. Therefore, by using this aluminum foil as a metal foil, the physical properties of the packaging material can be improved. Strength and flex resistance can be improved,
Further, the metal foil layer can be thinned. The alloy No. Aluminum foil made of 8021 material is commercially available, and products of various companies can be obtained.

A coextruded film 3 constituting the third layer in the packaging material, that is, two linear low density polyethylene layers (L
LDPE) or low density polyethylene layer (LDPE) 3
The coextruded film having a and 3c and the nylon layer 3b sandwiched therebetween is particularly important for imparting high physical strength and flex resistance to the packaging material of the present invention. The material of the nylon layer 3b is not particularly limited. The thickness of each layer in the third layer and the total thickness thereof are not particularly limited, and may be determined as necessary. For example, the total thickness of the third layer is 20
In the case of μm, usually two LLDPE layers or L
Each of the DPE layers 3a and 3c has a thickness of 5 to 7 μm,
The thickness of the nylon layer 3b is 6 to 10 μm. In addition, 2
The two LLDPE layers or LDPE layers 3a, 3c need not have the same thickness.

Fourth layer LLDPE film or LD
The PE film 4 is usually the innermost layer of the package in order to ensure the sliding property between the inner surface of the package and the packaged object and the heat sealability. The thickness of this layer is usually 20-
The upper limit is 150 μm, and preferably the lower limit is 40 μm or more and the upper limit is 80 μm or less. If this thickness is less than 20 μm, the strength of the packaging material may be insufficient, while on the other hand, 150
If the thickness exceeds μm, it is difficult to produce the LLDPE film or the LDPE film, and the cost becomes high.

The high-barrier packaging material of the present invention has excellent light-shielding properties, gas barrier properties, physical strength, and bending resistance and can be used in a wide range, but is preferably liquid or powder. It is used as a material for forming a bag for filling a fluid such as a body, and particularly preferably is used as a material for forming a bag that needs to be filled with a large amount of a fluid that has severe light-shielding or gas barrier properties. To be done.

3 to 5 show an inner bag (10) for a bag-in-box formed by using the high barrier packaging material of the present invention.
FIG. 3 is a front view of the bag body 102 folded, FIG. 4 is a perspective view of the bag body 102 filled with contents, and FIG. 5 is a cross-sectional view of a wall surface. FIG.

The bag body 102 is an inner bag for a bag-in-box having a capacity of 20 liters, which is used for transporting and storing water and other liquids. This bag is suitable as a bag for filling oil, seasoning, etc., which are relatively strict in terms of light-shielding properties and gas barrier properties. Regarding the capacity, regardless of whether it is an inner bag for a bag-in-box or a bag for other purposes, when filling a relatively large amount of content, for example, a capacity of 5 liters or more is required. Suitable in some cases.

As shown in FIGS. 3 and 4, the bag body 102
Is a gusset bag, and when it is filled with contents, it becomes a cube or a rectangular parallelepiped. Further, as shown in FIG. 5, the bag body 102 has a shock-absorbing structure having a double wall, the outer wall of which is the packaging material 101 of the present invention, while the inner wall thereof is a single film of LLDPE or LDPE. Is.

The bag body 102 is formed so as to have a pair of opposed flat surface portions 21 and 22 constituting the front side and the back side of the bag and a valley fold line 24 folded inward in a fold shape. The bag body is a four-sided seal having a side surface portion 23 and a top seal portion 25, a bottom seal portion 26, and a side surface seal portion 27 on the periphery of the bag body, and each corner portion 28 of the bag body.
It has a closed seal portion 29 and a triangular fin portion 30. Although each of the plane portions 21 and 22 and each of the side surface portions 23 is rectangular, a part of them may be square. A pouring member 31 including a spout and a cap is provided near the top of the bag 102.

Adhesion for forming the top sealing portion 25, the bottom sealing portion 26, the side sealing portion 27 and the closing sealing portion 29 is usually performed by a heat sealing method. It is possible to omit a part of the seal portion by bending and forming the packaging material for forming the bag body.

Each corner 28 of the bag body has a bag body 10 at the time of filling.
The closed seal portion 29 is formed in order to make the shape of the cube 2 as close to a cube or rectangular parallelepiped as possible and to form a triangular fin portion 30 at each corner portion 28. The closing seal portion 29 is in a state in which the bag body 102 is folded such that the pair of flat surface portions 21 and 22 are overlapped with each other and the two side surface portions 23 having the valley fold line 24 are interposed between the overlapped flat surface portions. That is, in the state shown in FIG. 3, the inner surfaces of the bag bodies facing each other are extended from an arbitrary position P of any one of the top seal portion and the bottom seal portion to an arbitrary position Q of the side seal portion. It is formed by adhering in a linear strip shape.

Similarly to the above, from the viewpoint that the bag body 102 at the time of filling has a shape as close to a cube or a rectangular parallelepiped as possible, the arbitrary position P is at the top seal portion 25 and the bottom seal portion 26 and the valley fold line 24 as much as possible. It is preferable to be close to the intersection point with, and it is particularly preferable to set on this intersection point. Further, from the same viewpoint as described above, it is preferable that the closing seal portions having the positional relationship on the right side and the left side of the bag, the front side and the back side, and the top side and the bottom side are as symmetrical as possible.

From the same viewpoint as above, it is preferable that the closing seal portion 29 is formed so that the triangular fin portion 30 has a shape as close as possible to an isosceles right triangle. For that purpose, a narrow angle m (m1, m2) sandwiched between any one of the top seal portion and the bottom seal portion and the closed seal portion, and a narrow angle n sandwiched between the side seal portion and the closed seal portion. (N1, n2) is usually 30 to 60 °
Preferably, the narrow angle m1 sandwiched between the top seal portion and the closed seal portion is 45 to 55 °, and the narrow angle m2 sandwiched between the bottom seal portion and the closed seal portion is 40 to 50 °.

At each corner 28 of the bag body, a top seal portion 25 is provided.
And any one of the bottom seal portions 26,
By being surrounded by the side seal portion 27 and the closing seal portion 29, a triangular fin portion 30 is formed integrally with the closing seal portion 29. The inner space of the triangular fin portion 30 is completely separated from the inner space of the bag body by the closing seal portion 29, so that the contents filled in the bag cannot enter the fin portion. Therefore, even if each corner portion 28 is bent when the bag body 102 is housed in the outer box, the residual liquid is not accumulated in the corner portion, and the residual liquid discharge performance of the bag-in-box is improved. Furthermore, the closing seal portion 29 integrally formed with the triangular fin portion is
Since the stress is dispersed in the impact, the impact resistance of the bag is improved.

In the triangular fin portion 30, the inner surfaces of the bags facing each other are entirely adhered to each other to form the fin portion 3
There may be no space in 0, or the inner surfaces of the bag may be partially or intermittently bonded.

A pair of top seal portions 25 or a pair of bottom seal portions 26 existing on the front side and the back side of the bag body and facing each other are partially or wholly adhered like an R portion. According to the above, a pair of left and right hanging portions may be formed on the top side or the bottom side of the bag body. By forming this hanging portion, it becomes possible to insert a mechanical hand into the hanging portion and lift the bag body. Further, by forming the hanging portion, (1) the triangular fin portion 30 is formed.
Does not get in the way. (2) Since the triangular fin portion 30 is interposed between the upper or lower surface of the outer box and the outer wall of the portion of the bag filled with the contents, the bag is rubbed by vibration or the like, Ancillary effects such as tearing or preventing pinholes can also be obtained.

The pouring member 31 is usually made of synthetic resin, but from the viewpoint of further improving the gas barrier property of the bag, it is preferable to use the pouring member of gas barrier resin. . Here, examples of the gas barrier resin include resins such as EVOH and resin mixtures containing these resins. Further, from the viewpoint of further perfecting the light-shielding property of the bag body, it is preferable that the pouring member 31 also has the light-shielding property.

To give the pouring member a light-shielding property, for example, the pouring member is colored, a light-shielding film is formed on the surface of the pouring member, or a colored plastic layer is formed inside the pouring member. Such a light shielding layer is formed. Here, when it is desired to color the pouring member, a pigment may be mixed in the resin material. Further, when it is desired to form a light-shielding film, a colored paint is applied to the surface of the pouring member, or a light-shielding shrink film is coated. As the light-shielding shrinkable film, for example, a composite film having at least a heat-shrinkable film layer and an aluminum foil layer can be exemplified. The composite film having the aluminum foil layer has not only the light-shielding property but also the gas barrier property and the water vapor barrier property, so that it is one of the suitable light-shielding films.

In such a composite film, the laminated interface between the layer of aluminum foil and another layer adjacent thereto is
It is preferable to use one that is adhered only in a strip-shaped region arranged at a predetermined interval, in which case the shrinkage of the film is achieved despite the fact that the aluminum foil is laminated in the composite film. Is good. In addition, the strip-shaped region which becomes an adhesive portion between the aluminum foil and the other layer,
Usually, it is set in a plurality of parallel lines or a grid pattern.

When the bag material is formed using the packaging material of the present invention, the bag material may be normally formed using only the packaging material of the present invention, or the packaging material of the present invention and other packages. The materials may be overlaid to form a multi-walled bag. FIG.
FIG. 4 is a diagram schematically showing a cross section of the bag body 102. The bag body 102 has a double wall and has a buffer hammer structure. The outer wall is the packaging material 101 of the present invention, and the ON film 1 as the first layer faces the outside of the bag body, and the LLDPE film or the LDPE film 4 as the fourth layer faces the inside of the bag body. . On the other hand, as the inner wall 32, a single film of LLDPE or LDPE is used in order to secure the slidability with LLDPE or LDPE which is the innermost layer of the outer wall, and to secure the heat sealability and the slidability of the innermost layer of the inner wall. are doing. Instead of this single film, a composite film in which the outermost layer and the innermost layer are formed of LLDPE or LDPE may be used.

The inner wall 32 is superposed in such a manner that the contact surfaces of the outer wall and the inner wall can slide freely in order to absorb an external force such as impact or friction applied from the outside or the body to be packaged to the wall surface of the bag body. . That is, the contact surfaces of the outer wall and the inner wall are not basically adhered to each other except the respective seal portions on the peripheral edge of the bag body, and the space 33 exists between the contact surfaces. However, if the sliding properties of both contact surfaces can be secured, there may be a locally bonded portion 34.
Further, the outer wall and the inner wall may be pseudo-bonded with a weak adhesive strength that allows peeling. When the packaging material for the outer wall and the packaging material for the inner wall are pseudo-bonded, it is convenient to handle at the stage of manufacturing the bag.

[0043]

[Examples] Experimental examples are shown below. (1) Barrier property test First, samples of the packaging material and the pouring member were prepared.

[Sample of packaging material (outer layer ← / → inner layer)] (a) Sample 1: 15 μm ON / 9 μm embossed Al foil / 20 μm coextruded film (breakdown: 5
μm LLDPE / 10 μm Ny / 5 μm LLDP
E) / 60 μm LLDPE (b) Comparative sample 1: 15 μm coextruded film (breakdown: 5 μm Ny / 5 μm EVOH / 5 μm Ny)
/ 20 μm PE / 60 μm LLDPE In addition, the meaning of each symbol is as follows: ON is biaxially stretched nylon film, Al foil is aluminum foil, LLDPE is linear low density polyethylene film, Ny is unstretched nylon film, EVOH is ethylene / The vinyl alcohol copolymer film and PE are polyethylene films.

[Sample of pouring member] (a) Sample 2 (pouring member): An EVOH spout 31a and a cap 31b shown in FIG. 6 were prepared, and the pouring member 31 with the cap fastened to the spout was used. It was used as a sample. As for the dimensions of each part, height H is 30.3 mm and outer diameter D
1 was 35.0 mm, the inner diameter D2 was 31.9 mm, and the thinnest part of the spout had a wall thickness T of 1.55 mm.

(B) Comparative sample 2 (pouring member): molding
Same pouring as Sample 2 except the material is PE
The member was designated as Comparative Sample 2. And each sump above
Oxygen permeability (unit: cc /
m^Two・ Day) is measured, and water vapor is measured by the so-called pouch method.
Transmittance (unit: g / m ^Two・ Day) was measured. Result first
The results are shown in Table 2. Pouch method test, sample packaging material
To any size (for example, internal dimensions 100 mm x 100 mm)
The bag is formed into a bag and filled with potassium chloride.
Stored in an environment of 40 ℃, 90% RH,
The weight change was measured over time. And the measured value obtained
1m^TwoThe amount of water vapor permeation was calculated.

[0047]

[Table 2] (2) Drop test First, a bag sample was prepared.

[Sample of Bag] (a) Sample 3: A bag having a shape and a double wall structure shown in FIGS. 3 to 5 was formed. Sample 1 for the outer wall
Was used, and LLDPE having a thickness of 60 μm was used for the inner wall. Each dimension of the bag has a width of 250 mm, a depth (width of the gusset portion) of 115 mm, and a height of 460 mm.
And the capacity was 10 liters.

(B) Sample 4: A bag was formed under the same conditions as in Sample 3, except that the following packaging materials were used. Outer wall (outer layer ← / → inner layer): 15 μm ON / 9 μm
Alloy No. 8021 material Al foil / 15μm ON / 60
μm LLDPE Inner wall: 60 μm LLDPE (c) Comparative sample 3: A bag was formed under the same conditions as in sample 3 except that the following packaging materials were used.

Outer wall (outer layer ← / → inner layer): 15 μm ON / 9 μm Al foil / 15 μm ON / 60 μm L
LDPE inner wall: LLDPE of 60 μm And, 10 liters of water was filled in the bag body of each of the above samples, and the bottom surface of the bag was dropped, the gusset surface of the bag was dropped, or the back surface of the bag was lowered. Any one of the falling toward the side was observed once, and it was observed whether bag breakage or water leakage occurred.

Drop distance is 0.5 m, 1.0 m, 1.5
The height was gradually raised using the same sample by setting four stages of m and 2.0 m, and the test was stopped at the stage when bag breakage or water leakage occurred. However, the drop test at 2.0 m was performed three times for the sample that reached the height of 2.0 m. The number of samples in one group was 2. Third result
It is shown in the table.

[0052]

[Table 3] * ○: No bag breakage or water leakage occurred. X: Bag breakage or water leakage occurred and the subsequent tests were stopped.

According to the results of the above-mentioned barrier property test, Sample 1, which is the packaging material of the present invention, has lower oxygen permeability and water vapor permeability than conventional transparent packaging materials and has excellent barrier properties. It is recognized that Also, excellent barrier properties are observed in Sample 2 in which the pouring member is formed of a gas barrier resin.

On the other hand, according to the results of the above drop test, the bag having the double-wall structure using the packaging material of the present invention can withstand a drop from a height of at least 1.5 m, and the aluminum foil. It is noted that it has stable strength with superior strength compared to conventional packaging materials containing layers.

From these results, the packaging material of the present invention is
It can be understood that it has a light-shielding property and a gas barrier property which are superior to those of the conventional transparent packaging material, and has sufficient strength to withstand a large-capacity bag body.

[0056]

As described above, the packaging material of the present invention has excellent light shielding properties, gas barrier properties, physical strength, and bending resistance, and can be used in a wide range. In particular, when a bag for filling a fluid such as liquid or powder is formed using this, a bag having excellent impact resistance and pinhole resistance can be obtained. Therefore, the bag formed using the packaging material of the present invention can be used as a durable bag having excellent light-shielding properties and gas barrier properties, and in particular, it is filled with a relatively large amount of fluid of about 5 liters or more. It can be suitably used as a bag body for doing.

As a preferred application example of the present invention, for example,
An example is an inner bag for a bag-in-box, which is used to fill the contents that are required to have light-shielding properties and gas barrier properties. In this case, an incomplete outer light-shielding box such as a folding container can be used, which is very convenient.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a cross section of a packaging material of the present invention.

FIG. 2 is an explanatory view showing how the embossed metal foil disperses impact stress.

FIG. 3 is a front view of an example of a bag body formed by using the packaging material of the present invention in a folded state.

FIG. 4 is a perspective view showing a state where the bag body of FIG. 3 is filled with contents.

5 is a view schematically showing a horizontal cut surface of the bag body of FIG. 3 in a filled state.

FIG. 6 is a diagram showing a shape of a pouring member used as a sample in an experimental example.

[Explanation of symbols]

 101 ... Packaging material of the present invention 102 ... Bag of the present invention 1 ... Stretched nylon film 2 ... Metal foil 3 ... Co-extruded film 4 ... LLDPE or LDPE film 5 ... Adhesive 21 ... Front flat part 22 ... Rear side Plane part 23 ... Side part 24 ... Valley fold line 25 ... Top seal part 26 ... Bottom seal part 27 ... Side seal part 28 ... Corner part 29 ... Closed seal part 30 ... Triangular fin part 31 ... Pouring member

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B65D 65/16 B65D 65/16 81/24 81/24 D

Claims (6)

[Claims] 1. A high barrier packaging material comprising a composite film in which the following first to fourth layers are laminated in this order. First layer: stretched nylon film, second layer: metal foil, third layer: coextruded film having two linear low-density polyethylene layers or low-density polyethylene layers, and a nylon layer sandwiched therebetween. 4th layer: Linear low-density polyethylene film or low-density polyethylene film. 2. The metal foil or alloy No. is embossed. The high barrier packaging material according to claim 1, which is an aluminum foil made of 8021 material. 3. The wall surface of the bag body is formed of one packaging material or two or more packaging materials laminated so that each contact surface can slide, and at least one of the packaging materials constituting the wall surface. A bag is characterized in that the sheet is the high barrier packaging material according to claim 1 or 2. 4. The wall surface of the bag body is formed by two overlapping packaging materials, and the outer wall of the wall surface is formed of the high barrier packaging material according to claim 1 or 2, and the high barrier thereof. The packaging material is arranged such that the first layer is the outer layer and the fourth layer is the inner layer, and the inner wall has a linear low density polyethylene film or an outer layer formed of a low density polyethylene film. 4. It is composed of a film having an inner layer.
The bag described in. 5. The bag according to claim 3, wherein the bag body is provided with a pouring member, and the pouring member is formed of a gas barrier resin and has a light shielding property. body. 6. The bag body according to claim 3, which is used as an inner bag for a bag-in-box.