JP6899267B2 - Inner bag for bag-in-box and its manufacturing method - Google Patents

Description

The present invention relates to a bag-in-box, and more particularly to an inner bag housed in an outer box of the bag-in-box and a method for manufacturing the same.

The bag-in-box has an outer box made of corrugated cardboard or the like and an inner bag housed inside the bag-in-box (see Patent Document 1 and the like). The inner bag includes a bag-shaped sheet and a tubular spout / outlet portion. Generally, a bag-shaped sheet is formed by laminating a plurality of flexible resin sheets by heat sealing or the like to form a bag-shaped sheet. An opening is formed in one place of the bag-shaped sheet, and a spout portion is attached to the opening. The spout portion is an injection-molded product that is separate from the bag-shaped sheet, and is joined to the bag-shaped sheet by a heat seal or the like.
The inside of the inner bag is filled with liquids such as beverages, detergents and chemicals. If necessary, the liquid can be poured out from the spouting port and used.

Japanese Unexamined Patent Publication No. 2001-348065

When manufacturing the inner bag of a conventional bag-in-box, it is necessary to join a plurality of resin sheets of the bag-shaped sheet with a heat seal or the like, or to join the bag-shaped sheet and the spout part with a heat seal or the like. It was complicated, required a lot of work, and took a long time to manufacture. In addition, if there is a poor joint, there is a risk of liquid leakage from there. In addition, the joints were prone to wrinkles, which made them look unattractive.
In view of such circumstances, it is an object of the present invention to provide an inner bag for a bag-in-box that can be easily manufactured, has no risk of joint failure, and has a good appearance.

In order to solve the above problems, the present invention is an inner bag housed in an outer box of a bag-in-box.
It has a relatively thin and flexible single bag-shaped sheet that is closed except for the opening of 1, and a relatively thick and hard tubular spout and outlet provided in the opening. However, the bag-shaped sheet and the spout portion are a continuum formed of the same resin material without having a joint portion between them.
"Closed except for the opening of 1" means that the inside of the bag-shaped sheet is completely closed when the opening of 1 is closed.
A "single piece" is a bag-shaped sheet in which the entire bag-shaped sheet is composed of one sheet, and a physical or mechanical joint portion in which a plurality of sheets are joined to the bag-shaped sheet by heat sealing, adhesion, sewing, etc. Say it doesn't exist.
Further, in the inner bag, there is no physical or mechanical joint portion such as heat seal, adhesion, sewing, etc. between the bag-shaped sheet and the spout portion. Therefore, there is no possibility that poor joining will occur, and the appearance of the inner bag can be improved.

It is preferable that the bag-shaped sheet has a symmetrical shape with respect to one virtual surface including the axis of the spout portion. By doing so, when the bag-shaped sheet is blow-molded or the like, the thickness of the bag-shaped sheet can be made uniform as a whole.

It is preferable that the spout portion is provided on one surface of the bag-shaped sheet, and the axis of the spout portion is inclined with respect to the first surface. By doing so, the content liquid can be easily poured out from the spout portion.

It is preferable that a continuous portion is interposed between the bag-shaped sheet and the spout portion, and the continuous portion has a conical shape whose diameter is reduced as it protrudes toward the spout portion. As a result, the bag-shaped sheet and the spout portion can be smoothly connected in shape.

A continuous portion is interposed between the bag-shaped sheet and the spout portion, and the thickness of the first continuous portion with the bag-shaped sheet in the continuous portion is equal to the thickness of the spout portion, and the continuous portion. It is preferable that the thickness of the second continuous portion with the spout portion is equal to the thickness of the spout portion. As a result, the bag-shaped sheet and the continuous portion can be integrally continuous with the same thickness as each other, and the spout portion and the continuous portion can be integrally continuous with the same thickness as each other. The thick-walled spout portion can be integrally continuous via the continuous portion.
It is preferable that the axis of the continuous portion is coaxial with the axis of the spout portion and is inclined with respect to the surface of 1.

The method of the present invention is a method for manufacturing an inner bag housed in an outer box of a bag-in-box.
Prepare a preform made of test tube-shaped resin with a spout formed at one end and the opposite end closed.
A single bag-shaped sheet that is thinner and more flexible than the spout portion from the preform portion by heating and expanding the preform portion that is continuous with the spout portion in the preform by fluid pressure. Is characterized by forming.
According to the method of the present invention, an inner bag for a bag-in-box can be easily manufactured. Although the manufacturing method is completely different from the conventional bag-in-box inner bag, it is possible to realize a bag-in-box inner bag that is close to the conventional bag-in-box inner bag.

According to the present invention, it is possible to provide an inner bag for a bag-in-box that can be easily manufactured, has no risk of joint failure, and has a good appearance.

FIG. 1 shows an inner bag for a bag-in-box according to an embodiment of the present invention, and is a front view taken along the line I-I of FIG. FIG. 2 is a plan view of the inner bag along the line II-II of FIG. FIG. 3 is a side view of the inner bag along the line III-III of FIG. FIG. 4 is a perspective view of the inner bag. FIG. 5 is an enlarged cross-sectional view of a continuous portion between the spout portion of the inner bag and the bag-shaped sheet along the VV line of FIG. 6 (a) to 6 (e) are explanatory views showing the manufacturing process of the inner bag.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 to 4 show an inner bag 10 for a bag-in-box. The inner bag 10 is housed in a corrugated cardboard outer box (not shown), and is filled with liquids such as beverages, detergents, and chemicals to be used.

The material of the inner bag 10 is made of a resin such as polyethylene (PE). The material of the inner bag 10 is not limited to polyethylene, and may be another resin such as polypropylene (PP) or polyethylene terephthalate (PET).

The bag-in-box inner bag 10 includes a bag-shaped sheet 11 and a spout portion 12.
The bag-shaped sheet 11 is a single piece that is closed except for the opening 11e of 1. The single bag-shaped sheet 11 does not have physical or mechanical joints such as heat seals and adhesives.

As shown in FIG. 4, the design shape of the bag-shaped sheet 11 is, for example, a rectangular parallelepiped shape or a cube shape, but the design shape is not limited to this. The design shape refers to the shape of the bag-shaped sheet 11 in a state of being inflated by the action of internal pressure.
As shown in FIGS. 1 and 2, the design shape of the bag-shaped sheet 11 is preferably a symmetrical shape with respect to a certain virtual surface 15. Here, the virtual surface 15 is arranged at the center of the inner bag 10 in the left-right direction and is orthogonal to the left-right direction.

The bag-shaped sheet 11 is thin and flexible. Therefore, the bag-shaped sheet 11 has almost no self-standing shape retention property, and can hardly retain its shape without the internal pressure and the support from the outside by the outer box.
_{The thickness t 11} (FIG. 5) of the bag-shaped sheet 11 _{is about t 11} = several μm to several hundred μm.

The spout portion 12 is provided in the opening 11e of the bag-shaped sheet 11 via the continuous portion 13. The spout portion 12 is formed in a tubular shape, and a screw portion 12c (FIG. 5) is formed on the outer peripheral surface thereof. The spout portion 12 is thicker and harder than the bag-shaped sheet 11, and has sufficient self-supporting shape retention. _{The thickness t 12} (FIG. 5) of the peripheral wall of the spout portion 12 excluding the screw portion 12c _{is, for example, t 12} = 1 mm to several mm.

As shown in FIGS. 1 to 3, the spout portion 12 is arranged at the center of the side 11c on the front surface 11b side, for example, on the upper surface 11a (the surface of 1) of the bag-shaped sheet 11. The location of the spout portion 12 can be set as appropriate.

As shown in FIG. 3, the axis 12x of the spout portion 12 is inclined forward of the bag-shaped sheet 11 (in the direction from the back surface 11d to the front surface 11b) as it protrudes from the upper surface 11a of the bag-shaped sheet 11. There is. Preferably, the axis 12x of the spout portion 12 is arranged on the virtual surface 15. In other words, the virtual surface 15 includes the axis 12x.

As shown by the alternate long and short dash line in FIG. 5, the cap 14 is attached to the threaded portion 12c of the spout portion 12. As a result, the spout portion 12 is closed, and the inside of the bag-shaped sheet 11 is completely closed.
When using the bag-in-box, the content liquid can be poured out from the inner bag 10 by removing the cap 14. Although not shown, when using the bag-in-box, after removing the cap 14, a cock or nozzle with a lever that can be opened and closed for pouring the content liquid may be attached to the spout portion 12.

As shown in FIGS. 1 to 3, a continuous portion 13 is provided between the bag-shaped sheet 11 and the spout portion 12. The bag-shaped sheet 11 and the spout portion 12 are integrally connected via the continuous portion 13. That is, the bag-shaped sheet 11 and the continuous portion 13 are integrally connected, and the continuous portion 13 and the spout portion 12 are integrally connected. The bag-shaped sheet 11, the continuous portion 13, and the spout portion 12 are continuous bodies formed of the same resin material such as polyethylene (PE) without having a joint portion between them.

As shown in FIG. 4, the continuous portion 13 has a conical shape that protrudes from the upper surface 11a of the bag-shaped sheet 11 and gradually reduces in diameter toward the tip end side in the protruding direction. A spout portion 12 is provided at the tip of the continuous portion 13. As shown in FIG. 3, the axis of the continuous portion 13 is coaxial with the axis 12x of the spout portion 12, and is inclined toward the front surface 11b (right side in FIG. 3) as it protrudes from the upper surface 11a of the bag-shaped sheet 11. Has been done. The portion of the continuous portion 13 on the front surface 11b side is extremely narrow. On the front surface 11b side, the spout portion 12 and the bag-shaped sheet 11 are close to each other or substantially directly connected to each other.

As shown in FIG. 5, the continuous portion 13 is thicker than the bag-shaped sheet 11 and thinner than the spout portion 12. Therefore, the continuous portion 13 has a hardness or softness about halfway between the bag-shaped sheet 11 and the spouting port portion 12, and has higher shape retention than the bag-shaped sheet 11.
The continuous portion 13 may have the same thickness as the bag-shaped sheet 11 and have the same flexibility as the bag-shaped sheet 11.
Alternatively, the continuous portion 13 may have the same thickness as the spout portion 12 and the same hardness as the spout portion 12.
The continuous portion 13 may become thicker and gradually harder from the bag-shaped sheet 11 toward the spout portion 12.
In any case, the thickness of the continuous portion 13 is equal to or about the same as that of the bag-shaped sheet 11 in the first continuous portion 13a with the bag-shaped sheet 11, and is noted in the second continuous portion 13b with the spout portion 12. It has the same or the same thickness as the outlet portion 12. As a result, the thin bag-shaped sheet 11 and the thick spout portion 12 are integrally continuous via the continuous portion 13.

The inner bag 10 of the bag-in-box is manufactured as follows.
<Preform manufacturing process>
As shown in FIG. 6A, the preform 19 is manufactured by injection molding the resin that is the material of the inner bag 10 by the injection molding unit 21.

<Preform 19>
As shown in FIG. 6B, the preform 19 has a test tube shape including the preform portion 19a and the spout portion 12 integrally. One end of the preform 19 (the upper end in FIG. 6B) is opened, and the spout portion 12 is formed therein. That is, the spout portion 12 of the inner bag 10 is manufactured by injection molding during the preform manufacturing process.
The portion of the preform 19 excluding the spout portion 12 (the portion below the spout portion 12 in FIG. 6B) constitutes the preform portion 19a. The preform portion 19a is continuous with the spout portion 12 without passing through a joint portion. The end portion (lower end portion in FIG. 6B) opposite to the spout portion 12 in the preform portion 19a is closed.

<Biaxial stretch blow molding>
The inner bag 10 is formed by biaxially stretching blow molding the preform 19.
<Heating process>
Specifically, as shown in FIG. 6C, first, the preform portion 19a of the preform 19 is introduced into the heating portion 22 and heated.
For example, the heating unit 22 has a pair of heating plates 22a, 22a facing each other. The preform portion 19a of the preform 19 is passed between the heating plates 22a and 22a. As a result, the preform portion 19a is softened.
The hardness of the spout portion 12 of the preform 19 is maintained by keeping the temperature lower than that of the preform portion 19a, preferably at room temperature.

<Expansion process>
Subsequently, as shown in FIG. 6D, the preform 19 is introduced into the blow molding unit 23 and set in the blow molding mold 24. Although not shown, the blow molding unit 23 is provided with a stretching rod that can move up and down. By inserting the stretching rod into the preform 19 from the spout portion 12, the preform portion 19a is stretched in the axial direction (downward in FIG. 6D). Further, by introducing blow air (fluid pressure) from a blow air nozzle (not shown) into the inside of the preform 19 from the spout portion 12, the preform portion 19a expands in the radial direction orthogonal to the axial direction. Let me.

As shown in FIG. 6D, the preform portion 19a is expanded until it is pressed against the mold surface 24a of the blow molding mold 24, and is formed with a single bag-shaped sheet 11 which is thinner and more flexible than the spout portion 12. Become. Moreover, the bag-shaped sheet 11 is continuous with the spout portion 12 via the continuous portion 13.
Since the bag-shaped sheet 11 has a symmetrical shape with respect to the virtual surface 15 (FIGS. 1 and 2), it can be formed to have a uniform thickness as a whole, and good blow molding can be performed.
In this way, as shown in FIG. 6 (e), the inner bag 10 is produced from the preform 19.

The inner bag 10 is an integral body as a whole, and is heat-sealed, bonded, sewn, or other physically or mechanically between the bag-shaped sheet 11 and the spout portion 12 and also on the bag-shaped sheet 11 itself. There is no joint. Therefore, there is no risk of joint failure. Furthermore, the appearance of the inner bag 10 can be improved.
According to the embodiment of the present invention, it is possible to realize the bag-in-box inner bag 10 which is close to the conventional bag-in-box inner bag, although the manufacturing method is completely different from the conventional bag-in-box inner bag.

The present invention is not limited to the above-described embodiment, and various modifications can be made as long as it does not contradict the gist thereof.
For example, the location of the spout portion 12 in the inner bag 10 is not limited to the central portion of one side 11c, but may be a corner portion of three surfaces or may be near the center of one surface 11a.
The axis 12x of the spout portion 12 may be orthogonal to the surface 11a on which the spout portion 12 is arranged.
The axis of the continuous portion 13 may be orthogonal to the surface 11a on which the continuous portion 13 is arranged.
The continuous portion 13 may be omitted, and the spout portion 12 may be provided directly on the bag-shaped sheet 11.

The present invention can be applied to, for example, a bag-in-box filled with drinking water.

10 Inner bag for bag-in-box 11 Bag-shaped sheet 11a Upper surface (1 surface)
11b Front 11c Side 11d Back 11e Opening 12 Injection outlet 12c Threaded part 12x Axis 13 Continuous part 13a First continuous part 13b Second continuous part 14 Cap 15 Virtual surface 19 Preform 19a Preform part 21 Injection molding part 22 Heating part 22a Heating plate 23 Blow molding part 24 Blow molding mold 24a Mold surface

Claims (4)

An inner bag that is housed in the outer box of the bag-in-box.
It has a relatively thin and flexible single bag-shaped sheet that is closed except for the opening of 1, and a relatively thick and hard tubular spout and outlet provided in the opening. and, these pouched sheet and spout portion, Ri continuum der formed homologs of the same resin material without a bonding portion therebetween,
The spout portion is provided on one surface of the bag-shaped sheet, and the axis of the spout portion is inclined with respect to the surface of 1.
A continuous portion is interposed between the bag-shaped sheet and the spout portion, and the continuous portion has a conical shape whose diameter is reduced so as to project along the axis toward the spout portion.
The continuous portion, the bag-shaped with thicker than the sheet, and the watch bag-in-box for the bag, wherein the thin der Rukoto than the outlet section. The inner bag for a bag-in-box according to claim 1, wherein the bag-shaped sheet has a symmetrical shape with respect to one virtual surface including the axis of the spout portion. A continuous portion is interposed between the bag-shaped sheet and the spout portion, and the thickness of the first continuous portion with the bag-shaped sheet in the continuous portion is equal to the thickness of the spout portion, and the continuous portion. The inner bag for a bag-in-box according to claim 1 or 2, wherein the thickness of the second continuous portion with the spout portion is equal to the thickness of the spout portion. A method of manufacturing an inner bag that is housed in the outer box of a bag-in-box.
Prepare a preform made of test tube-shaped resin with a spout formed at one end and the opposite end closed.
A single bag-shaped sheet that is thinner and more flexible than the spout portion from the preform portion by heating and expanding the preform portion that is continuous with the spout portion in the preform by fluid pressure. Is formed, the spout portion is provided on one surface of the bag-shaped sheet, the axis of the spout portion is inclined with respect to the surface of 1, and the bag-shaped sheet and the spout portion A continuous portion is interposed between the continuous portions, and the continuous portion has a conical shape whose diameter is reduced so as to project along the axis toward the spout port, and the continuous portion is larger than the bag-shaped sheet. A method for manufacturing an inner bag for a bag-in-box, which is formed to be thick and thinner than the spout portion.

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