JP3124672B2 - Bags for milk bag-in-box - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a bag-in-box (Bag-in-box).
in Box) For bags, especially raw milk, milk, processed milk, etc.
The present invention relates to a bag for a milk bag-in-box, which is suitably used for transporting and storing a liquid classified as “milk” according to a ministerial ordinance.

[0002]

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

[0003] This bag-in-box uses a foldable bag-in-box bag or container made of plastic for the interior and a corrugated cardboard box exterior to the interior, and has water resistance and chemical resistance to the contents liquid. The structure is such that the gas barrier properties and the like are given to the interior plastic bag or container, while the rigidity required for transportation and storage is given to the exterior. Compared to conventional glass bottles, tin cans, etc., the bag-in-box constructed in this way does not require collection, which contributes to labor saving and cost saving, and is easy to transport and store empty containers because it can be folded. This has the advantage that the distribution cost can be reduced.

On the other hand, as containers for liquids classified as "milk" in the ordinance of the Ministry of Milk, such as raw milk, milk, and processed milk, containers made of polyethylene-processed paper called so-called milk cartons have been widely used.

However, the above milk carton is
Although it has excellent properties mainly as a small container for home use, it has a drawback that it is not always suitable in terms of its capacity, strength, etc., for example, for business use or transportation between factories.

Here, for example, the use of a bag-in-box as a large container suitable for business use or transportation between factories is conceivable, but the conventional bag-in-box is required for containers such as raw milk and milk. Those that sufficiently satisfy the required properties such as safety and strength have not yet been developed.

Accordingly, the applicant of the present application has developed a bag for a milk bag-in-box which sufficiently satisfies various characteristics such as safety and strength required for containers of raw milk, milk and the like, and has already filed an application. (Japanese Patent Application Nos. 5-120802 and 5-222380).

As shown in FIG. 3, for example, this milk bag-in-box bag is made of high-density polyethylene (HDP).
E) and a low-density polyethylene (LDPE) coextruded PE film (eg, HDPE / LDPE or H
DPE / LDPE / HDPE, etc.), and these co-extruded PE films are laminated without being bonded to each other to form a co-extruded PE film group laminated body 2. After the two sheets are overlaid, the four-side seal portion 3 is formed by four-side sealing. Furthermore, in this bag 1 for a bag for a dairy bag, the co-extrusion 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.

In the above-mentioned bag for a dairy bag-in-box, the innermost layer of the bag body and the injection pouring port which are in direct contact with the contents of "milk" are both formed by LDPE. In addition, sufficient safety and strength satisfying the above-mentioned standards are secured, recycling is easy, and heat sealability is also secured.

[0010] The outermost layer of the bag body is formed of an HDPE layer. This HDPE layer has excellent heat resistance and mechanical strength, is not affected by heat during heat sealing, and is hard to expand. As a result, an excellent dairy bag-in-box bag can be obtained.

Furthermore, since the co-extruded PE films are superposed without bonding, and the facing layer between the co-extruded PE films is an LDPE layer, the slip between the co-extruded films is good. From the viewpoint of distribution, a favorable buffer effect is exhibited.

[0012]

However, in the bag for a dairy bag-in-box, the four corners (corner portions) of the bag cannot be said to have sufficient impact resistance, 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 of the present invention is to provide a bag for a milk bag-in-box, which has improved impact resistance at four corners of the bag.

In order to achieve the above object, a bag for a dairy bag-in-box according to the present invention has a bag body made of a polyethylene (PE) film, and an infusion spout attached to the bag body. A bag body, wherein the bag body is formed by bonding two or more PE films including at least one co-extruded film of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) without adhering between the PE films; The bag body is made of a PE film group laminate obtained by laminating, the bag body is formed by sealing four sides in a state where the two PE film group laminates are overlapped, and the innermost layer of the bag body is LDPE. A spout made of LDPE, wherein the spout is formed by a layer, and wherein the pouring spout is heat-sealed to the inner surface of the bag body, and H attached to the spout. In dairy bag-in-box bag body consisting of a PE caps, some four corners of the bag body a configuration in which dropped off the curved bulging outward of the bag.

The bag for a dairy bag-in-box according to the present invention is the bag for a dairy bag-in-box described above,
The four corners of the four-side seal are sealed in a curved shape that bulges outside the bag body.

Further, in the bag for a milk bag-in-box according to the present invention, if necessary, the outermost layer of the bag main body is formed of the HDPE layer of the co-extruded PE film in the bag for a milk bag-in-box. There is a configuration that has been.

The bag for a dairy bag-in-box according to the present invention, if necessary, is a bag for a dairy bag-in-box, wherein the bag body is formed of a plurality of coextruded PE films made of HDPE and LDPE. Each of the co-extruded PE films is made of a laminated body of co-extruded PE films obtained by laminating the co-extruded PE films without bonding, and the bag body is composed of two co-extruded P films.
The E-film group laminated body is formed by sealing in four sides in a state of being overlapped, and the innermost layer of this co-extruded PE film group laminated body is configured to be an LDPE layer.

Further, the bag for a dairy bag-in-box according to the present invention may be arranged such that, if necessary, the outermost layer of the co-extruded PE film group laminate is an HDPE layer in the bag for a dairy bag-in-box. The facing layers between the co-extruded PE films are each configured as an LDPE layer. Particularly preferably, the co-extruded PE film group laminate is formed by laminating only three co-extruded PE films, and the outer co-extruded PE film is the outermost high-density polyethylene (HDPE) layer from the outside to the inside. And low density polyethylene (L
DPE) layer, and the middle co-extruded PE film has three layers of a low density polyethylene (LDPE) layer, a high density polyethylene (HDPE) layer, and a low density polyethylene (LDPE) layer from the outside to the inside. The inner co-extruded PE film has a low density polyethylene (LDPE) layer, a high density polyethylene (HDPE) layer, and an innermost low density polyethylene (L) layer.
(DPE) layer.

Further, the bag for a milk bag-in-box according to the present invention has a configuration in which the inside of the four-side seal portion is further overlapped by a four-side seal in the bag for a milk bag-in-box as required.

[0020]

The bag for a milk bag-in-box according to the present invention has a configuration in which four corners of the bag are cut off in a curved shape.
Since the four corners of the four-sided seal are sealed in a curved shape, the four corners of the bag are excellent in impact resistance, and even if the four corners of the bag collide with the exterior, there is no possibility that the four corners may be damaged.

[0021]

EXAMPLES Next, examples of the present invention will be shown, and the present invention will be described more specifically. FIG. 1 is a plan view showing an embodiment of the bag for a milk bag-in-box according to the present invention.

As shown in FIG. 1, the bag 1 for a dairy bag-in-box according to the present invention comprises a plurality of PE films.
It is formed by laminating two E film group laminates 2 and then sealing the four-side seal part 3 four-sidedly, and further includes an injection spout 4.

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

The milk bag-in-box bag 1 of the present invention is characterized in that the four corners 6 of the four-side seal portion 3 are sealed in a curved shape. Here, the curved shape at the time of sealing the four corners 6 of the four-side seal portion 3 of the bag body 1 in a curved shape is a curved shape suitable for impact mitigation. 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-side seal part 3 in a curved shape, the seal may be performed using a heat-sealing mold in which R is previously provided at the four corners of the four-side seal 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-side sealing portion 3 of the bag 1 in a curved shape" can be used independently. 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 dairy bag-in-box bag 1 of the present invention is obtained by laminating two specific PE films, that is, two PE film laminates 2 each composed of a plurality of PE films, and then sealing the four-side seal part 3 four-sidedly. It is formed.

In this embodiment, as shown in FIG. 2, the PE film group laminate 2 is made of high-density polyethylene (HDPE) and low-density polyethylene (L
DPE) and three co-extruded PE films 11, 12, and 13 formed from the outside by co-extrusion.
The co-extruded PE film 12 / co-extruded PE film 13 are simply superposed and formed in this order without bonding between the films.

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

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

The burst strength and the pinhole are not required to satisfy a certain standard by a special application under the ordinance of the Ministry of Milk and the like. However, the bursting strength is 5 kgf / cm ² when the “milk”, which is the content of the bag body 1 formed using these polyethylenes, is a low-temperature distribution product.
As described above, it is preferably 8 kgf / cm ² or more in the case of a product distributed at ordinary temperature. For pinholes,
Preferably, there is no pinhole.

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
50 μm. Further, the thickness of the LDPE layer 11b is usually 70 μm to 120 μm. In this embodiment, H
The thickness of the DPE layer 11a is 30 μm, and the LDPE layer 1
The thickness of 1b is 100 μm.

A co-extruded PE film 12 is superimposed on and adjacent to the co-extruded PE film 11 constituting the outermost layer. The co-extruded 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 with the E layer 12c.

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

The coextruded PE film 1 constituting the middle layer
In FIG. 3, a co-extruded PE film 13 is superimposed adjacent thereto. The layer configuration of the co-extruded PE film 13 constituting the innermost layer and the thickness of each
It is the same as E film 12.

As described above, the layer structure of the bag body 1 is such that the [HDPE layer 11a / LDPE layer 11
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 by HDPE, and the innermost layer is formed by LDPE.

Here, the reason why the outermost layer is formed of HDPE is that HDPE is superior in heat resistance and mechanical strength as compared with LDPE, is not affected by heat during heat sealing, and is hardly stretched, so that holes are hardly opened. The reason why the innermost layer is formed of LDPE is to ensure heat sealability.

Each of the co-extruded PE films 11, 12,
Numeral 13 is a four-sided seal and laminated, and the co-extruded PE films are not laminated on the whole surface. Therefore, slippage occurs between the opposing layers between the coextruded PE films, but the opposing layers between the coextruded PE films are all LDPE.
Since the layer is a layer, the layer has good slippage, and a favorable buffering effect is obtained in distribution.

The bag body 1 having such a structure is provided with an LD, similarly to the conventional bag for a milk 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 constituting the innermost layer of the bag body 1 and a spout 21 made of LDPE are heat-sealed, and a 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.

The sealing strength of the bag thus formed must be free from breakage and air leakage. The dairy bag-in-box bag 1 of the present invention is not limited to the above-described embodiment, and may be appropriately modified and implemented.

For example, the PE film group laminate 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 Layer (thickness 70-120μ)
m)] + LDPE film (40-80 μm thickness) + L
A triple bag made of a DPE film (thickness of 40 to 80 μm) (PE film group laminate), [HDPE layer (thickness of 30 to 80 μm)
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)] (double co-extruded PE film group laminate) 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
４０40 μm) / LDPE layer (thickness 20 to 40 μm)] +
[LDPE layer (thickness: 20 to 40 μm) / HDPE layer (thickness: 20 to 40 μm) / LDPE) layer (thickness: 20 to 40 μm)
m)] (a quadruple bag made of (co-extruded PE film group laminate)).

Also, instead of the outermost layer coextruded PE film composed of the HDPE layer / LDPE layer in the above-mentioned 2 to 4 double bags, the outermost layer coextruded Pd composed of the LDPE layer / HDPE layer is replaced with
An E film may be used. Thus, when the outermost layer co-extruded PE film is an LDPE layer / HDPE layer,
The impact strength can be improved.

More 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 figure) in the bag making process, but the heat sealing makes the surface resistant. HDPE deteriorates, and the distance between the middle layer and the inner layer co-extruded PE film as the sealant is too long to obtain sufficient impact strength. For example, when the bag is dropped only from a height of 60 cm with a bag, the bag breaks Will occur. on the other hand,
The outermost layer co-extruded PE film in the above-described embodiment is represented by L
In the case of the DPE layer / HDPE layer, even if the bag is dropped five times with only the bag from a height of 90 cm, the bag does not break and sufficient impact strength is obtained.

The bag for a dairy bag-in-box according to the present invention is different from the bag for a dairy bag-in-box in the above embodiment in that the inside of the four-side seal portion is further overlapped by a four-side seal (double seal). ). In this case, it is preferable that the four corners of the inner four-side seal are also sealed in a curved shape.

This bag for milk bag-in-box can be particularly suitably used as a container for products classified as "milk" in ministerial ordinances such as raw milk, milk and processed milk.
Used in the state of being stored in the outer cardboard box.

[0046]

As described above, according to the bag for a 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-side seal portion are cut off. Is sealed in a curved shape, so that the four corners of the bag are excellent in impact resistance, and even if the four corners of the bag collide with the exterior, there is no possibility that this portion will be damaged.

[Brief description of the drawings]

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Bag for milk bag-in-box 2 ... Laminated body of PE film group 3 ... Four-side seal part 4 ... Injection and pouring tool 5 ... Four corners of bag body 6 ... Four corners of four-side seal part 11 ... Co-extruded 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 (7)

(57) [Claims] 1. A bag for a bag-in-box comprising a bag body made of a polyethylene (PE) film, and an injection spout attached to the bag body, wherein the bag body is made of high-density polyethylene (HDPE). A PE film group laminate obtained by laminating two or more PE films containing at least one co-extruded film of a low-density polyethylene (LDPE) with each other without bonding between the PE films, wherein the bag body is The two PE film group laminates are formed so as to be sealed on all sides in a state of being overlapped, and the innermost layer of the bag body is LDPE.
A dairy bag-in-box bag, comprising a spout made of LDPE, wherein the spout is formed by heat-sealing the inner surface of the bag body, and a cap made of HDPE attached to the spout. Bag the four corners of the body
A bag for a dairy bag-in-box, characterized in that it is cut off in a curved shape bulging outside the body. 2. The bag for a dairy bag-in-box according to claim 1, wherein the four corners of the four-side seal portion are located outside the bag.
2. The bag for a milk bag-in-box according to claim 1, wherein the bag is sealed in an inflated curved shape . 3. The bag for a dairy bag-in-box according to claim 1, wherein an outermost layer of the bag body is formed by an HDPE layer of the co-extruded PE film. Or the bag for a milk bag-in-box according to 2 above. 4. The bag for a dairy bag-in-box according to claim 1, wherein said bag body is made of HDPE and L.
A plurality of co-extruded PE films made of DPE
It consists of a co-extruded PE film group laminate obtained by laminating without bonding between E films, and the bag body is formed by sealing four sides in a state where two co-extruded PE film group laminates are superimposed. And this co-extrusion P
The bag according to any one of claims 1 to 3, wherein the innermost layer of the E film group laminate is an LDPE layer. 5. The dairy bag-in-box bag according to claim 4, wherein the outermost layer of the coextruded PE film group laminate is an HDPE layer, and a facing layer between the coextruded PE films is an LDPE layer. The bag for a milk bag-in-box according to claim 4, characterized in that: 6. A dairy bag-in-box according to claim 5.
In the bag for use, the co-extruded PE film group laminate has three co-extruded PE films.
Only the film is overlapped, and the outer co-extruded PE
Lum is the outermost high-density polyethylene from outside to inside.
Len (HDPE) layer and low density polyethylene (LDPE)
Consists of a two-layer structure, and the intermediate co-extruded PE film is
Low-density polyethylene (LDP)
E) layer and high-density polyethylene (HDPE) layer and low-density polyethylene
It consists of a three-layer structure with a polyethylene (LDPE) layer,
Coextruded PE film has low density from outside to inside
Polyethylene (LDPE) layer and high density polyethylene (H
DPE) layer and innermost layer of low density polyethylene (LDPE)
6. A three-layer structure comprising a plurality of layers.
Bag for dairy bag in box. 7. The method of claim 1 to dairy bag-in-box bag body according 6, claims 1, characterized in that superimposed by further four-side sealed inside the four-side sealed portion according to 6 or Bag for milk bag-in-box.