JP2005263326A - Bag-in-box container for milk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bag-in-box container for milk which has sufficient strength, and provides sure sealing performance while being simple, and to provide a cap equipped with sealing performance and easy opening performance. <P>SOLUTION: This bag-in-box container for milk is formed into a bag-shape by heat-sealing a polyethylene film, equipped with a spout, and used for housing raw milk, milk, processed milk or the like. In the bag-in-box container for milk, a forming material of the container comprises two sheets or more of a film. For the cap for the bag-in-box container for milk, the surface layer of each film is always made of low density polyethylene (LDPE), and an uneven section is formed on the internal cylindrical section. Then, the length of the external cylindrical section is made shorter than the length of the internal cylindrical section. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

Industrial application fields

  The present invention relates to a polyethylene container used in a bag-in-box for mainly storing liquid dairy products such as raw milk and cow milk, and in particular, has a sufficient strength and easily provides a reliable sealing property. The present invention relates to a dairy bag-in-box container and a method for producing the same.

Conventional technology

  The bag-in-box is composed of a bag-like container that contains a plastic foldable liquid product and an outer box such as a cardboard box that accommodates the container. This bag-in-box is used for transporting and storing various liquids such as beverages such as mineral water and industrial chemicals.

  On the other hand, as a liquid container classified as “milk” according to the ordinance of milk, such as raw milk, cow milk, processed milk, etc., a polyethylene processed paper container called a milk carton has been used so far. According to the above-mentioned ministerial ordinance, it is required that the container material be an additive-free homopolyethylene and have a burst strength of 5 kgf / cm @ 2 or more (when chilled).

  However, since conventional milk containers such as milk cartons have insufficient strength, pinholes may be formed in the container or broken due to twisting of the container film due to vibration during transportation or direct impact. There was no practical use as a large container for business use.

  Then, utilization of the bag in box which added intensity | strength as a large sized container of such milk is proposed. For example, in JP-A-7-2274, as shown in FIG. 6, a bag body for a bag-in-box comprising a bag body 1 made of polyethylene film and an inlet 2 attached to the bag body. The bag body is formed by laminating two or more polyethylene films including at least one coextruded film made of high density polyethylene (HDPE) and low density polyethylene (LDPE) with a four-side seal, and the outermost layer is A high density polyethylene (HDPE) made of extruded film is formed, and a spout 21 made of low density polyethylene (LDPE) is heat-sealed at the inlet, and a cap 22 made of high density polyethylene (HDPE) is attached to the spout 21. A bag for a dairy bag-in-box is disclosed. In FIG. 6, reference numeral 3 denotes a four-way seal portion.

  However, according to the conventional dairy bag-in-box container, the required strength and legal regulations are satisfied, but in order to produce this, the outermost layer (exactly the outermost layer in the outermost film) is required. Since it is always necessary to be high density polyethylene (HDPE), there has been a problem that the outermost film surface must be confirmed and stacked when manufacturing the container. In addition, when manufacturing the constituent material of the container to be used with two or more films stacked (hereinafter referred to as a multiple film), the high density polyethylene (HDPE) surface of one film and the low film of the other film When the density polyethylene (LDPE) surfaces face each other, the heat sealability of both films deteriorates, and the seal between the films may peel off during use.

  The present invention has been made in view of the above problems, and in order to provide sufficient strength and simple yet reliable sealing performance, heat-sealed polyethylene film is formed into a bag shape, raw milk provided with an inlet, In a container for a dairy bag-in-box for storing milk, processed milk, etc., the container is made of two or more films, and the surface layer of each film is always made of low-density polyethylene (LDPE). A container for a dairy bag-in-box is provided.

  As for the laminated film, well-known coextruded film production methods such as inflation, T-die, lamination method and the like can be applied. In particular, in the case of the inflation method, an inflated laminated film such as a laminated film made of LDPE / HDPE / LDPE. When the film is deflated and stacked as it is, two layers of the same film can be formed in one process, that is, a two-layer film of LDPE / HDPE / LDPE film and LDPE / HDPE / LDPE film can be made. Simplified and extremely convenient.

Action

  Since the surface layer of each film constituting the multiple film (however, the film itself in the case of a single layer film) is always made of low density polyethylene (LDPE), the density is always low when two or more films are laminated. Polyethylene (LDPE) faces each other and heat sealability can be reliably obtained. Further, it has been experimentally confirmed that low density polyethylene (LDPE) is less likely to generate pinholes than high density polyethylene (HDPE), and the contents can be further protected.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows a multiplex film 10 which is a material for forming a dairy bag-in-box container according to the present invention. Enlarged sectional views of the respective films constituting the multiplex film 10 are shown in the circle of FIG. According to FIG. 1, the multiple film 10 is composed of four films: an outermost film 11, intermediate films 12 and 13, and an innermost film 14. The thickness of each film is 80 μm for film 11, 80 μm for film 12, 60 μm for film 13, and 60 μm for film 14.

  The outermost film 11 is composed of a low density polyethylene (LDPE) layer 11a, a high density polyethylene (HDPE) layer 11b, and a low density polyethylene (LDPE) layer 11c, and these layers are laminated by coextrusion. The intermediate film 12 has the same layer structure as the film 11 and is laminated by coextrusion. The intermediate film 13 and the innermost film 14 are both low density polyethylene (LDPE) extruded films.

  Here, high density polyethylene (HDPE) in the present invention 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. In addition, these high-density polyethylene (HDPE) and low-density polyethylene (LDPE) are all required to satisfy the following criteria for dissolution tests on heavy metals, evaporation residue and potassium permanganate consumption. That is, during the dissolution test (60 ° C., 30 minutes), 1 ppm or less for heavy metals (leaching solution 4% acetic acid), 15 ppm or less for evaporation residue (leaching solution 4% acetic acid), permanganate consumption (erosion) About 5 ppm of the solution water). However, the burst strength is 5 kgf / cm 2 or more when the “milk” as the contents of the container formed using these polyethylene films is a low-temperature distribution product, and 8 kgf / It is preferably at least cm2.

  From the above, the structure of the multiplex film 10 of the dairy bag-in-box container of this example is [low density polyethylene (LDPE) 11a / high density polyethylene (HDPE) 11b / low density polyethylene (LDPE) from the outside to the inside. 11c] + [low density polyethylene (LDPE) 12a / high density polyethylene (HDPE) 12b / low density polyethylene (LDPE) 12c] + [low density polyethylene (LDPE) 13] + [low density polyethylene (LDPE) 14] The surface layer of all the films (however, in the case of a single layer film, the film itself) is made of low density polyethylene (LDPE). Therefore, the contact surface between each film is always a combination of low density polyethylene (LDPE) and low density polyethylene (LDPE). Furthermore, the outermost layer 11a and the innermost film 14 of the outermost film 11 are formed of low density polyethylene (LDPE).

  Here, high-density polyethylene (HDPE) is superior in heat resistance and mechanical strength to low-density polyethylene (LDPE), but has a property that it is difficult to heat-seal and hardly stretch. On the other hand, low density polyethylene (LDPE) has low mechanical strength, good heat sealability, and has a property of being easily stretched. Therefore, the films 11 and 12 laminated by combining high density polyethylene (HDPE) and low density polyethylene (LDPE) are rich in mechanical strength, while the films 13 and 14 made of low density polyethylene (LDPE) have good elongation. Therefore, the multiple film 10 made of these films has both characteristics.

  The films 11, 12, 13, and 14 are four-side sealed and overlapped, and the films are not bonded to each other. Therefore, although slip occurs between the opposing surfaces in each film, the opposing surfaces are all made of low density polyethylene (LDPE) in the examples of the present invention. A preferable buffer effect is obtained.

  In the multiple film having the above-described configuration, a low-density polyethylene (LDPE) grommet (spout) 21 and a low-density polyethylene (LDPE) made by fitting with the grommet 21 are the same as those shown in FIG. A cap 22 is attached.

  The shape of the cap 22 includes, for example, biped annular fitting portions 23 and 24 as shown in FIG. This is because in the conventional bag-in-box, a rubber cap having a shape as shown in FIG. 5 (B) was used, but in the present invention, a polyethylene material must be used due to the restriction of a ministerial ordinance such as milk. This is because the shape was found to be very poorly openable. That is, in the conventional rubber cap, since the rubber itself is flexible, the bottomed fitting portion 25 can be used as shown in FIG. However, since the cap 22 of this container is made of polyethylene, it is extremely difficult to open the cap when such a bottomed fitting portion is used. In view of this, the cap 22 of the present container has a thin annular fitting portion 24 as shown in FIG. 5A in order to give a certain flexibility to the fitting portion.

  Note that the film configuration of the multiple film 10 is not limited to that according to the above-described embodiment, for example, two layers of films made of a low density polyethylene (LDPE) / high density polyethylene (HDPE) / low density polyethylene (LDPE) laminate, Three or four layers, or two layers of low density polyethylene (LDPE) / high density polyethylene (HDPE) / low density polyethylene (LDPE) laminate and low density polyethylene (LDPE) film A film configuration is possible. Since a film whose surface layer is always low density polyethylene (LDPE) may be used, for example, a film made of a laminate of LDPE / HDPE / HDPE / LDPE, LDPE / HDPE / LDPE / HDPE / LDPE, etc. is also used. it can.

  Next, another embodiment relating to heat sealing of the multiple film 10 will be described. As shown in FIG. 2 to FIG. 4, the heat seal portion can take various modes.

  In the first embodiment, as shown in FIG. 2, a four-side seal portion 4 is further provided inside the four-side seal portion 3. In this case, it is desirable that the inner four-side seal 4 is a seal that causes the separation of the seal surface, thereby enabling the impact from the internal liquid to be absorbed by the separation of the seal surface. In addition, air etc. can also be enclosed between the two four-way seals 3 and 4, and cushioning properties are improved.

  In the second mode, as shown in FIG. 3, the inner four-side seal 5 is partially heat-sealed so that the liquid contained in the container can flow between the outer four-side seal portion 3. Is. In this example, the impact applied to the seal portion of the container can be released in the corner direction to effectively absorb the external impact.

  In the third aspect, as shown in FIG. 4, diagonal seal portions 6 are provided at four corners (or two corners) of the container. In this example, since the four corners of the container are flexible tabs, when the container containing the liquid is stored in the outer box and packed, the flap of the outer box, the guide arm of the automatic packing device, etc. This part is also less likely to be damaged when touching the corner.

  In the above embodiment, the seal portions 4, 5, 6 can be appropriately changed in design with respect to the distance from the outer seal portion 3, the seal width, and the seal strength.

  Next, an aspect of a cap suitable for the bag-in-box container of the present invention will be described.

  FIG. 7 shows one aspect of a cap suitable for a bag-in-box container according to the present invention. In this embodiment, the opening of the grommet inlet is formed in the cap fitted to the container mouth forming the opening. A cap body 30 to be covered, and an inner cylindrical portion 31 and an outer cylindrical portion 32 that extend downward from the outer peripheral portion of the cap main body 30 and are located on both sides of the opening, and the lower end of the outer cylindrical portion 32 is the lower end of the inner cylindrical portion 31. It is characterized by being shorter.

  Moreover, in this cap, you may provide the latching | locking part engaged with a container opening part in the internal peripheral surface of the outer side cylindrical part 32, and / or the outer peripheral surface of the inner side cylindrical part 31. FIG. In the example of FIG. 7, a belt-like convex portion 31 a is provided on the outer peripheral surface of the inner cylindrical portion 31.

  As described above, the cap according to the present invention has a cross-sectional structure as shown in the drawing, and is characterized in that the lower end of the outer cylindrical portion 32 is shorter than the lower end of the inner cylindrical portion 31. Excellent in both sex and openability.

  The preferred example shown in FIG. 8 is characterized in that a holding portion 34 fitted to the outer periphery of the mouth portion is connected to the lower end of the outer peripheral cylindrical portion 32 via a fracture portion 33. In this example, the breaking portion 33 is opened by pulling the pull-out portion 33a at the time of opening to be broken and removed at the cut band 33b formed in a ring shape at both ends of the breaking portion. After opening, the holding part 34 is separated from the cap body and remains in a state of being fitted to the outer periphery of the mouth part. Therefore, after opening, the lower end of the outer cylindrical portion 32 is shorter than the lower end of the inner cylindrical portion 31, so that the same effect as in the case of FIG.

  In this example, belt-like convex portions 31 a and 32 a are provided as locking portions on both the inner peripheral surface of the outer cylindrical portion 32 and the outer peripheral surface of the inner cylindrical portion 31.

[The invention's effect]
As described above in detail, according to the milk bag-in-box container of the present invention, milk for storing raw milk, cow milk, processed milk, etc., which is formed into a bag shape by heat sealing a polyethylene film and has an inlet. In a bag-in-box container, the forming material of the container is composed of two or more films, and the surface layer of each film is always composed of low-density polyethylene (LDPE). Sealing performance can be provided.

The figure which shows the Example of the container for milk bag in boxes of this invention, and an enlarged view. The figure which shows the other Example of the heat seal location in the container of this invention. The figure which shows the other Example of the heat seal location in the container of this invention. The figure which shows the other Example of the heat seal location in the container of this invention. (A) shows the cap shape used for the container of this invention, (B) is a figure which shows the cap shape of the container for conventional bag-in-boxes. The figure which shows the container for conventional bag-in-milk boxes. Sectional drawing of the Example of the cap used for the container of this invention. Sectional drawing of the Example of the cap used for the container of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 2 Inlet 3, 4, 5 Heat seal part 10 Multiple film 21 Grommet 22 Cap

Claims (3)

In the cap fitted into the container mouth part forming the opening,
A cap body covering the opening of the mouth;
An inner cylindrical portion and an outer cylindrical portion that extend downward from the outer peripheral portion of the cap body and are located on both sides of the mouth portion;
A polyethylene cap characterized in that the lower end of the outer cylindrical portion is shorter than the lower end of the inner cylindrical portion.   The polyethylene cap according to claim 1, wherein a holding portion that is fitted to the outer periphery of the mouth portion is connected to the lower end of the outer peripheral cylindrical portion via a fracture portion.   The polyethylene cap according to claim 1 or 2, wherein a locking portion that engages with the container mouth portion is provided on an inner peripheral surface of the outer cylindrical portion and / or an outer peripheral surface of the inner cylindrical portion.

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