JPH07187233A - Milk bag as bag in box - Google Patents

Abstract

PURPOSE:To enhance the impact resistance of the four corners of a bag by a method wherein, in the bag body having four-sided seal formed and a pour in and out mouth heat fused to the inner surface of the bag body, the four corners of the bag body are cut off into a curved form. CONSTITUTION:A milk bag 1 for use in a bag in box container is made by joining together two sheets of the PE film laminates each of which consists of a plurality of PE(polyethylene) films and thereafter by forming a four-sided seal 3 with a pour in and out mouth 4. The four corner parts 5 of the bag 1 are cut off into a curved form having a predetermined radius of curvature suitable to absorb impact. The four corner parts 6 of the four-sided seal 3 of the bag 1 are sealed into a curved form having a predetermined radius of curvature suitable to absorbe impact. Each PE film laminate 2 is formed of three sheets of PE films 11, 12 and 13 each of which is formed by coextrusion molding of a high-density and a low-density PE and which are just laid one upon another without being bonded together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a bag-in-box (Bag
in Box), especially raw milk, milk, processed milk, etc.
The present invention relates to a bag for a milk bag-in-box, which is preferably used for transportation and storage of a liquid classified as “milk” in accordance with the Ordinance of Ministry of Milk and the like.

[0002]

2. Description of the Related Art In recent years, a bag-in-box, which is a so-called one-way container of a disposable type, has been widely used for transporting and storing various liquids such as beverages such as mineral water and industrial chemicals.

This bag-in-box is a bag-in-bag body or container made of plastic and foldable, which is used as an interior, and a corrugated cardboard box is packaged in the interior. The internal plastic bag or container is responsible for gas barrier properties, and the exterior is responsible for the rigidity required for transportation and storage. Compared with conventional glass bottles, tin cans, etc., the bag-in-box configured in this way is labor-saving and cost-saving because it does not need to be collected, and because it is foldable, it is easy to transport and store empty containers. This has the advantage that distribution costs can be reduced.

On the other hand, as a container for liquids classified as "milk" according to the Ordinance of the Ministry of Milk such as raw milk, milk, processed milk, etc., a polyethylene processed paper container called a so-called milk carton has been widely used.

However, the above milk carton
Although it has excellent properties mainly as a small-sized container for household use, it has a drawback that it is not necessarily suitable in terms of capacity, strength, etc., for applications such as commercial use or transportation between factories.

Here, the bag-in-box can be considered as a large container suitable for commercial use or transportation between factories, and the conventional bag-in-box requires a container for raw milk, milk or the like. Those which fully satisfy various characteristics such as safety and strength have not been developed yet.

[0007] Therefore, the applicant of the present application has developed and has already applied for a bag body for a milk bag in box that sufficiently satisfies various characteristics such as safety and strength required for containers of raw milk, milk and the like. (Japanese Patent Application No. 5-120802 and Japanese Patent Application No. 5-222380).

This bag for dairy bag-in-box is, for example, as shown in FIG.
E) and low density polyethylene (LDPE) coextruded PE film (eg HDPE / LDPE or H
Two or more sheets of DPE / LDPE / HDPE, etc.) are used and the respective coextruded PE films are laminated without adhering to each other to form a coextruded PE film group laminate 2. The two four-sided seal portions 3 are formed by sealing four sides after stacking two sheets. Furthermore, in this bag body 1 for bag for milk, coextrusion P
The outermost layer of the E film group laminate 2 is an HDPE layer, the facing layer between the coextruded PE films is an LDPE layer, and the innermost layer of the coextruded PE film group laminate 2 is an LDPE layer.
As a layer.

Since the innermost layer of the bag main body and the injection pouring outlet which are in direct contact with the "milk" which is the content are formed of LDPE in the bag for dairy bag-in-box, the milk etc. Sufficient safety and strength satisfying the standard of (3) are secured, recycling is easy, and heat sealability is secured.

The outermost layer of the bag body is formed of an HDPE layer. The HDPE layer is excellent in heat resistance and mechanical strength, is not affected by heat at the time of heat sealing, and is difficult to stretch and has holes. Since it is difficult to obtain, an excellent bag for dairy bag-in-box can be obtained.

Further, since the coextruded PE films are superposed on each other without adhering and the facing layers between the coextruded PE films are respectively LDPE layers, the slip between the coextruded films is good, In terms of distribution, a preferable buffering effect is exhibited.

[0012]

However, in the bag body for dairy bag-in-box, the impact resistance of the four corners (corner portions) of the bag is not sufficient, and the four corners of the bag collide with the exterior. When this was done, there was a risk that this part would be damaged.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a bag for dairy bag-in-box, which has improved impact resistance at the four corners of the bag.

[0014]

In order to achieve the above object, a bag for dairy bag-in-box according to the present invention comprises a bag main body made of polyethylene (PE) film, and an injection spout attached to the bag main body. A bag body for a bag-in-box, wherein the bag body is made of high-density polyethylene (H
DPE) and a low-density polyethylene (LDPE) coextruded PE film comprising at least two PE films laminated together without adhering each PE film to each other. The bag body is formed by sealing in four directions in a state where the two PE film group laminated bodies are overlapped with each other, the innermost layer of the bag body is formed of an LDPE layer, and the injection spout is the bag body. In a bag for dairy bag-in-box, which comprises an LDPE spout that is heat-sealed to the inner surface of and a HDPE cap that is attached to the spout, the four corners of the bag are cut off in a curved shape. .

The bag for dairy bag in box of the present invention is the bag for dairy bag in box as described above.
It is configured such that the four corners of the four-sided sealing portion are curvedly sealed.

Further, in the bag for dairy bag-in-box of the present invention, in the bag for dairy bag-in-box, the outermost layer of the bag body is formed of the HDPE layer of the coextruded PE film, if necessary. It has been configured.

Further, the bag for dairy bag-in-box of the present invention is, if necessary, in the bag for dairy bag-in-box, the bag body comprises a plurality of coextruded PE films made of HDPE and LDPE. It consists of a coextruded PE film group laminate obtained by stacking each coextruded PE film without adhering them, and the bag body has two coextruded P films.
The E film group laminate is formed by sealing in four directions in a stacked state, and the innermost layer of this coextrusion PE film group laminate is an LDPE layer.

Further, the bag for dairy bag-in-box of the present invention is, if necessary, in the bag for dairy bag-in-box, the outermost layer of the coextruded PE film group laminate is an HDPE layer, The facing layers between the coextruded PE films are LDPE layers.

The bag for dairy bag-in-box according to the present invention is constructed such that the inside of the four-sided seal portion is further overlapped by a four-sided seal in the bag for dairy bag-in-box.

[0020]

The bag body for a milk bag-in-box according to the present invention has a configuration in which the four corners of the bag body are cut off in a curved shape.
Since the four corners of the four-sided sealing portion are curvedly sealed, the four corners of the bag have excellent impact resistance, and even if the four corners of the bag collide with the exterior, these parts are not likely to be damaged.

[0021]

EXAMPLES Examples of the present invention will now be described to more specifically describe the present invention. FIG. 1 is a plan view showing an embodiment of the bag body for a milk bag-in-box according to the present invention.

As shown in FIG. 1, the bag body 1 for a bag-in-box for milk of the present invention comprises P made of a plurality of PE films.
It is formed by stacking two sheets of the E film group laminate 2 and then sealing the four-way sealing part 3 in four directions, and further includes an injection pouring port 4.

The bag 1 for bag-in-box for milk of the present invention is characterized in that the four corners 5 of the bag 1 are cut off in a curved shape (corner cut). Here, bag 1
The curved shape when the four corners 5 are cut off in a curved shape is a curved shape suitable for impact relaxation. Specifically, for example, it has a curved shape having a predetermined radius of curvature. The method and timing of cutting off the four corners 5 of the bag body 1 in a curved shape are not particularly limited, but for example, four-way sealing is sequentially performed on a continuous film to form the bag body 1 continuously, and then the adjacent bags are formed. Body 1
In the step of cutting the gaps to obtain the individual bag bodies 1, the bag bodies 1 may be cut off in the same manner as when the bag bodies 1 are cut at the same time.

The bag 1 for bag-in-box 1 for milk of the present invention is characterized in that the four corners 6 of the four-sided seal portion 3 are curvedly sealed. Here, the curved shape when sealing the four corners 6 of the four-sided sealing portion 3 of the bag body 1 in a curved shape is a curved shape suitable for impact relaxation. Specifically, for example, it has a curved shape having a predetermined radius of curvature. Bag 1
In order to seal the four corners 6 of the four-sided sealing part 3 in a curved shape, the sealing may be performed using a heat-sealing die in which R is provided in advance at the four corners of the four-sided sealing part.

The above-mentioned "cutting off the four corners 5 of the bag 1 in a curved shape" and "sealing the four corners 6 of the four-sided sealing portion 3 of the bag 1 in a curved shape" may be independently performed. Although it contributes to the improvement of the impact resistance at the four corners of the bag, the combination of the two contributes most to the improvement of the impact resistance at the four corners of the bag.

The bag 1 for bag-in-box for dairy products according to the present invention comprises a specific PE film, that is, two PE film group laminates 2 each composed of a plurality of PE films, which are superposed on each other, and then the four-sided seal portion 3 is sealed on four sides. Is formed.

Here, in this embodiment, the PE film group laminate 2 is, as shown in FIG. 2, both high density polyethylene (HDPE) and low density polyethylene (L).
DPE) and three coextruded PE films 11, 12, and 13 formed by coextrusion from the outside.
/ Coextruded PE film 12 / Coextruded PE film 13 are simply superposed and formed without adhering between the films.

Here, in the present invention, high density polyethylene (HDPE) means polyethylene having a density of 0.94 or more, and low density polyethylene (LDPE) means polyethylene having a density of less than 0.94. Further, both of these high-density polyethylene (HDPE) and low-density polyethylene (LDPE) are required to satisfy the following criteria in the dissolution test for heavy metals, evaporation residues and potassium permanganate consumption.

That is, dissolution test (60 ° C., 30 minutes)
Medium, 1ppm or less for heavy metals (leaching solution 4% acetic acid), 15p for evaporation residue (leaching solution 4% acetic acid)
pm or less, potassium permanganate consumption (leaching solution water)
Is 5 ppm.

With respect to burst strength and pinhole, it is not required to meet certain standards by special application under the Ordinance of the Ministry of Milk and the like. However, regarding the burst strength, when the "milk" which is the content of the bag body 1 formed by using these polyethylene is a low temperature distribution product, it is 5 kgf / cm ²
As described above, in the case of a product that is distributed at room temperature, it is preferably 8 kgf / cm ² or more. For pinholes,
Preferably there are no pinholes.

Coextruded PE film 11 constituting the outermost layer
Has a two-layer structure of an HDPE layer 11a and an LDPE layer 11b, and the thickness of the HDPE layer 11a is usually 30 μm to
It is 50 μm. The thickness of the LDPE layer 11b is usually 70 μm to 120 μm. In this embodiment, H
The DPE layer 11a has a thickness of 30 μm, and the LDPE layer 1
The thickness of 1b is 100 μm.

The coextruded PE film 11 constituting this outermost layer is overlaid with the coextruded PE film 12 adjacent thereto. The coextruded PE film 12 constituting the middle layer is composed of the LDPE layer 12a, the HDPE layer 12b and the LDP.
It has a three-layer structure including the E layer 12c.

Here, the LDPE layers 12a and 12c and the HDPE layer 12b are usually 20 to 4 in thickness.
It is 0 μm. In this embodiment, the thickness of each layer is 2
It is set to 0 μm.

Coextruded PE film 1 constituting this middle layer
A coextruded PE film 13 is superposed on the No. 3 adjacent thereto. The layer structure and the thickness of each layer of the coextruded PE film 13 forming the innermost layer are the same as those of the coextruded P film 13.
It is similar to the E film 12.

From the above, the layer structure of the bag body 1 is [HDPE layer 11a / LDPE layer 11 from the outside to the inside.
b] / [LDPE layer 12a / HDPE layer 12b / LDP
E layer 12c] / [LDPE layer 13a / HDPE layer 13b
/ LDPE layer 13c], the outermost layer is formed of HDPE, and the innermost layer is formed of LDPE.

Here, the outermost layer is formed of HDPE because HDPE is superior in heat resistance and mechanical strength to LDPE, is not affected by heat at the time of heat-sealing, and is difficult to stretch and puncture. The reason for forming the innermost layer by LDPE is to ensure heat sealability.

Further, each coextruded PE film 11, 12,
13 is a four-sided seal and is laminated, and the entire surfaces of the coextruded PE films are not laminated together. Therefore, slippage occurs between the layers facing each other between the coextruded PE films, but all layers facing each other between the coextruded PE films are LDPE.
Since it is a layer, it has good slipperiness and exhibits a favorable cushioning effect in terms of distribution.

The bag body 1 having such a structure has the same LD as the conventional bag body for dairy bag-in-box shown in FIG.
An injection spout 4 including a spout 21 made of PE and a cap 22 made of HDPE is attached.

Specifically, the LDPE layer 13c forming the innermost layer of the bag body 1 and the spout 21 made of LDPE are heat-sealed together, and the screw cap 22 is attached to the spout 21. The spout 21 is attached to a spout hole (not shown) provided in the bag body 1.

Regarding the sealing strength of the bag formed in this way, it is necessary that there be no damage or air leakage. The bag 1 for bag-in-box for dairy products of the present invention is not limited to the above-mentioned embodiment, and is appropriately modified and implemented.

For example, the PE film group laminated body 2 constituting the bag body 1 is not limited to the one shown in FIG. 2, and may be, for example, [HDPE layer (thickness 30 to 50 μm) / LDPE in order from the outside. Layer (thickness 70-120μ
m)] + LDPE film (thickness 40 to 80 μm) + L
Triple bag made of DPE film (thickness 40 to 80 μm) (PE film group laminated body), [HDPE layer (thickness 30 to
50 μm) / LDPE layer (thickness 70 to 120 μm)] +
[LDPE layer (thickness 20 to 40 μm) / HDPE layer (thickness 20 to 40 μm) / LDPE layer (thickness 20 to 40 μm)
m)] (coextruded PE film group laminated body) double bag or [HDPE layer (thickness 30 to 50 μm) / L
DPE layer (thickness 70 to 120 μm)] + [LDPE layer (thickness 20 to 40 μm) / HDPE layer (thickness 20 to 40)
μm) / LDPE layer (thickness 20 to 40 μm)] + [LD
PE layer (thickness 20 to 40 μm) / HDPE layer (thickness 20
˜40 μm) / LDPE layer (thickness 20-40 μm)] +
[LDPE layer (thickness 20 to 40 μm) / HDPE layer (thickness 20 to 40 μm) / LDPE) layer (thickness 20 to 40 μm)
m)] (coextruded PE film group laminated body) or the like.

Further, instead of the outermost layer coextruded PE film composed of the HDPE layer / LDPE layer in the above-mentioned 2 to 4 layer bag, the outermost layer coextruded P composed of the LDPE layer / HDPE layer.
E film may be used. Thus, when the outermost coextruded PE film is the LDPE layer / HDPE layer,
The impact strength can be improved.

Specifically, in the configuration of the embodiment shown in FIG. 2 described above, heat sealing is performed from the outermost layer side (upper side in the drawing) in the bag making process. The HDPE with is deteriorated and the distance between the middle layer and the inner layer coextruded PE film, which is a sealant, is too long to obtain a sufficient impact strength. For example, if the bag is dropped only from a height of 60 cm, the bag is broken. Will occur. on the other hand,
The outermost layer co-extruded PE film in the above-mentioned embodiment is
When the DPE layer / HDPE layer is used, sufficient impact strength can be obtained without causing bag breakage even if the bag is dropped 5 times from a height of 90 cm.

The bag for dairy bag-in-box according to the present invention is the bag for dairy bag-in-box according to the above-mentioned embodiment, in which the inside of the four-sided sealing portion is further overlapped by a four-sided seal (double seal). ) Is good. In this case, it is preferable that the four corners of the inner four-sided seal portion are also curvedly sealed.

This bag for dairy bag-in-box can be particularly suitably used as a container for products classified as "milk" in accordance with a ministerial ordinance of milk such as raw milk, milk, and processed milk.
It is used as it is stored in an external cardboard box.

[0046]

As described above, according to the bag for dairy bag-in-box of the present invention, the four corners of the bag are cut off in a curved shape, and the four corners of the four-sided seal portion are formed. Since it is configured to be sealed in a curved shape, the four corners of the bag have excellent impact resistance, and even if the four corners of the bag collide with the exterior, these parts are not likely to be damaged.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a bag body for a milk bag-in-box according to the present invention.

FIG. 2 is a partial cross-sectional view showing an example of a PE film group laminate that constitutes the bag for a milk bag-in-box of the present invention.

FIG. 3 is a perspective view showing a conventional bag body for a milk bag-in-box.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Bag-in-box bag for milk 2 ... PE film group laminated body 3 ... Four-sided seal part 4 ... Injection pouring tool 5 ... Four corners of bag body 6 ... Four corners of four-sided seal part 11 ... Coextrusion PE film 11a ... High density polyethylene (HDPE) layer 11b ... Low density polyethylene (LDPE) layer 12 ... Coextruded PE film 13 ... Coextruded PE film 21 ... Spout 22 ... Cap

Claims (6)

[Claims] 1. A bag-in-box bag body comprising a bag body made of a polyethylene (PE) film and an injection spout attached to the bag body, wherein the bag body is a high density polyethylene (HDPE). PE obtained by stacking two or more PE films containing at least one co-extruded PE film of polyethylene and low density polyethylene (LDPE) without adhering between the PE films
It is composed of a film group laminate, and the bag body has two P
It is formed by sealing four sides in a state where the E film group laminated bodies are stacked, and the innermost layer of the bag body is LD.
A bag for dairy bag-in-box, which is formed of a PE layer and further comprises an LDPE spout in which the injection spout is heat-sealed to the inner surface of the bag body, and an HDPE cap attached to the spout, A bag for a milk bag-in-box, characterized in that the four corners of the bag are cut off in a curved shape. 2. The bag for dairy bag-in-box according to claim 1, wherein the four corners of the four-sided seal portion are curvedly sealed. . 3. The bag for dairy bag-in-box according to claim 1 or 2, wherein the outermost layer of the bag body is formed of an HDPE layer of the coextruded PE film. Alternatively, the bag body for a milk bag-in-box according to 2. 4. The bag body for a milk bag-in-box according to claim 1, wherein the bag body is HDPE and L.
Each co-extruded PE film made of DPE
The co-extruded PE film group laminated body obtained by superposing the E films without adhering each other, and the bag body is formed by sealing two sides of two co-extruded PE film group laminated bodies in a superposed state. This co-extrusion P
The bag body for bag-in-box for milk according to claim 1, wherein the innermost layer of the E film group laminate is an LDPE layer. 5. The bag for dairy bag-in-box according to claim 4, wherein the outermost layer of the coextruded PE film group laminate is an HDPE layer, and the facing layers between the coextruded PE films are LDPE layers. The bag body for a milk bag-in-box according to claim 4, characterized in that. 6. The bag bag for a milk bag in box according to any one of claims 1 to 5, wherein the inside of the four-sided seal portion is further overlapped by a four-sided seal. Box bag.