JP2020196520A - Manufacturing method of packaging bag and packaging bag - Google Patents

Abstract

To suppress molding defects when molding reinforcing members by injection molding.SOLUTION: A manufacturing method of a packaging bag includes: a laminating step of forming a laminated body in which a bottom surface sheet folded in half up and down is arranged between a pair of side surface sheets; a bonding step of bonding the laminated bodies in a bag shape to form a bag body 20; and a reinforcing member forming step of forming the reinforcing members on side portions of the bag body 20 by injection molding. The bag body 20 formed at the bonding step includes: a lower bonded portion 21 in which a lower portion of the side surface sheets and the bottom surface sheet are bonded; and a side bonded portion 25 in which the side portions of the side surface sheets are bonded to each other. An overlapped portion 23 extending so as to overlap a crease M of the bottom surface sheet is provided at an end portion of an upper edge portion 22 of the lower bonded portion 21. The side bonded portion 25 is provided with a protruding portion 26 that is in contact with the overlapped portion 23 and projects toward a center side.SELECTED DRAWING: Figure 3

Description

The present invention relates to a method for manufacturing a packaging bag and a packaging bag.

In the packaging bag 60 shown in FIGS. 8 and 9, a pair of side sheet 61s arranged to face each other and a bottom sheet 62 arranged between the side sheets 61 in a vertically folded state are adhered to each other. It includes a bag-shaped bag main body 63 and a columnar reinforcing member 64 that reinforces a side portion of the bag main body 63. The inner surface of the side sheet 61 is adhered to each other on the side portion of the bag body 63, and the inner surface of the side sheet 61 and the bottom sheet 62 are adhered to each other on the lower portion thereof.

As shown in FIG. 10A, the reinforcing member 64 includes a first wall portion 64a that covers one side of the bag body 63, a second wall portion 64b that covers the other side, and a first wall portion. It is formed in a U-shape in cross section including a third wall portion 64c that connects the 64a and the second wall portion 64b and covers the side edge of the bag body 63. The portion shown by the alternate long and short dash line in the bag body 63 of FIG. 10 means that the side sheet 61 and the bottom sheet 62 are adhered to each other.

As the packaging bag having the above configuration, for example, the one disclosed in Patent Document 1 is known.

Japanese Unexamined Patent Publication No. 2003-19964

By the way, as shown in FIGS. 9 and 10B, when the reinforcing member 64 is formed by injection molding, a partial dent 65 is formed in the first wall portion 64a and the second wall portion 64b of the reinforcing member 64. Molding defects sometimes occurred. When the molten resin is injected into the molding die for forming the reinforcing member 64, the recess 65 is formed on the side of the bottom sheet 62 because the molten resin enters between the bottom sheets 62 that are stacked in a non-adhesive state. It is formed by opening and floating the part.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for manufacturing a packaging bag and a packaging bag capable of suppressing molding defects when molding a reinforcing member by injection molding.

A method for manufacturing a packaging bag that solves the above problems includes a bag main body and a columnar reinforcing member that reinforces a side portion of the bag main body, and the bag main body includes a pair of side sheets arranged so as to face each other. A bag is formed by adhering a bottom sheet arranged between the side sheets in a vertically folded state, and the reinforcing member is a first wall portion covering one side of the side portion of the bag body. , A method for manufacturing a packaging bag including a second wall portion that covers the other surface side, and a third wall portion that connects the first wall portion and the second wall portion and covers the side edge of the bag body. In addition, a laminating step of forming a laminated body in which the bottom sheet in a vertically folded state is arranged between the pair of the side sheet sheets, and the bag-shaped bonding of the laminated body to form the bag body. The bag body includes a bonding step and a reinforcing member forming step of forming the reinforcing member on the side portion of the bag body by injection molding, and the bag body formed by the bonding step includes a lower portion of the side sheet and the bottom sheet. A lower adhesive portion to which the side sheets are bonded and a side adhesive portion to which the side portions of the side sheet are bonded to each other are provided, and the upper edge portion of the lower adhesive portion extends so as to overlap the crease of the bottom sheet. An overlapping portion is provided, and the side bonding portion is provided with a protruding portion that is in contact with the overlapping portion and projects toward the center.

According to the above configuration, with respect to the bag body formed by the bonding process, an overlapping portion that overlaps the crease of the bottom sheet and extends in the width direction is provided at the end of the upper edge of the lower bonding portion, and the side bonding portion is provided with an overlapping portion. A protruding portion is provided that protrudes toward the center in contact with the overlapping portion of the lower adhesive portion. As a result, when the reinforcing member is injection-molded, it becomes difficult to open the space between the bottom sheets, and the molten resin is suppressed from entering between the bottom sheets. As a result, it is possible to suppress molding defects when molding the reinforcing member by injection molding.

The packaging bag that solves the above problems includes a bag main body and a columnar reinforcing member that reinforces the side portion of the bag main body, and the bag main body is folded up and down with a pair of side sheets arranged to face each other. In this state, the bottom sheet arranged between the side sheets is adhered to form a bag shape, and the reinforcing member is the same as the first wall portion covering one side of the side portion of the bag body. A packaging bag including a second wall portion that covers the surface side, and a third wall portion that connects the first wall portion and the second wall portion and covers the edge of the side portion of the bag body. The main body includes a lower bonding portion in which the lower portion of the side surface sheet and the bottom surface sheet are bonded, and a side bonding portion in which the side portions of the side sheet are bonded to each other, and the end of the upper edge of the lower bonding portion. The portion is provided with an overlapping portion that extends so as to overlap the folds of the bottom sheet, and the side bonding portion is provided with a protruding portion that is in contact with the overlapping portion and projects toward the center.

According to the method for producing a packaging bag and the packaging bag of the present invention, it is possible to suppress molding defects when molding a reinforcing member by injection molding.

An exploded perspective view of the laminated body. Top view of the laminate. Top view of the bag body. Explanatory drawing of bonding process. Top view of the packaging bag. 6-6 sectional view of FIG. Explanatory drawing of the reinforcing member forming process. An exploded perspective view of a conventional packaging bag. Top view of a conventional packaging bag. (A) is a sectional view taken along line 10a-10a of FIG. 9, and (b) is a sectional view taken along line 10b-10b of FIG.

Hereinafter, an embodiment of the method for manufacturing a packaging bag of the present invention will be described.
The method for manufacturing a packaging bag according to the present embodiment includes a laminating step of forming a laminated body in which a plurality of sheet materials are stacked, an adhering step of adhering the laminated bodies in a bag shape to form a bag body, and a side portion of the bag body. It is provided with a reinforcing member forming step for forming the reinforcing member.

As shown in FIGS. 1 and 2, the laminating step is a step of forming a laminated body 10 by laminating a pair of side sheet 11 and bottom sheet 12. As the side sheet 11 and the bottom sheet 12, a multi-layered sheet material having a seal layer formed on one main surface side and a non-seal layer formed on the other main surface side is used. The seal layer is a layer made of a heat-welding resin material. Examples of the heat-weldable resin material constituting the seal layer include polyethylene, unstretched polypropylene, and an ethylene-vinyl acetate copolymer.

The non-seal layer is a layer made of a resin material having a lower heat welding property than the resin material forming the sealing layer, or a material having no heat welding property. Examples of the resin material having lower heat welding property than the resin material forming the seal layer include stretched polypropylene, polyester, polyamide, polyvinyl chloride, cellophane, and polystyrene.

The pair of side sheet 11s have a substantially vertically long rectangular shape, and are arranged so that the main surfaces formed of the seal layers face each other. The bottom sheet 12 has a horizontally long square shape having a width equal to the width of the side sheet 11, and is folded in half so that the crease M is located on the upper side and the main surface composed of the seal layer faces outward. , Arranged between a pair of side sheets 11. The pair of side sheet 11s and the bottom sheet 12 folded in half are stacked so as to align the side edges and the lower edges.

As shown in FIG. 3, the bonding step is a step of forming a bag-shaped bag body 20 having an opening upper edge by providing a lower bonding portion 21 and a side bonding portion 25 with respect to the laminated body 10. is there. The lower adhesive portion 21 and the side adhesive portion 25 are formed by pressing a heated sealing die against the laminate 10 and heat-welding the sealing layers of the pressed portions to each other.

The lower adhesive portion 21 is a portion of the bottom sheet 12 having a four-layer structure below the crease M, in which the lower portion of each side sheet 11 and the bottom sheet 12 are adhered to each other, and is formed from one side edge of the bag body 20. It is formed over the entire area between the upper edge 22 extending to the other side edge and the lower edge of the bag body 20.

The upper edge 22 of the lower adhesive portion 21 forms an arc shape in which the central portion is recessed downward and overlaps with the overlapping portion 23 that overlaps the crease M of the bottom sheet 12 and extends in the width direction from both end portions in the width direction. It has an arc portion 24 that connects the portions 23 to each other.

The surface of the bottom sheet 12 that faces inward when folded in half is formed of a non-seal layer. Further, a through portion such as a through hole or a notch is not formed in the portion of the bottom sheet 12 located at the lower adhesive portion 21. Therefore, when the lower adhesive portion 21 is formed, the bottom surface sheets 12 are not adhered to each other, and the side surface sheets 11 are not adhered to each other through the penetrating portion.

The side adhesive portion 25 is a portion of the laminated body 10 in which the side portions of the side sheet 11 are adhered to each other in a portion having a two-layer structure above the crease M of the bottom sheet 12, and the side surface from the crease M of the bottom sheet 12. It is formed along the side edge of the side sheet 11 up to the upper end of the side edge of the sheet 11.

At the lower end of the side adhesive portion 25, a protruding portion 26 projecting toward the center is provided. The protruding portion 26 is formed in a triangular shape that is in contact with the overlapping portion 23 of the upper edge 22 of the lower bonding portion 21 and whose protruding length becomes shorter toward the upper side. Further, the tip of the portion of the protruding portion 26 in contact with the overlapping portion 23 is located at the end portion 23a on the central side of the overlapping portion 23.

As shown in FIG. 4, in the bonding step, the sealing mold is pressed against the portion of the first region R1 to heat-weld the seal layers of the portion, and then the portion of the second region R2 is bonded. On the other hand, the sealing mold is pressed against each other to heat-weld the sealing layers of the relevant portion.

In the first region R1, the lower edge 10a of the laminate 10, the side edges 10b on both sides, both ends are located above the crease M of the bottom sheet 12, and the central portion is located below the crease M. This is a region surrounded by an arcuate inner edge 10c whose central portion is recessed downward.

The second region R2 is a region having a constant width extending from the upper end to the lower end along the side edges 10b on both sides of the laminated body 10, and the lower portion overlaps with the first region R1. When the intersection P of the inner edge 10c of the first region R1 and the crease M of the bottom sheet 12 is set, the width H of the second region R2 is set to be shorter than the length from the side edge 10b side to the intersection P. .. As a result, the side adhesive portion 25 having the protruding portion 26 in contact with the overlapping portion 23 is formed.

As shown in FIG. 5, the reinforcing member forming step is a step of forming resin reinforcing members 30 on both side portions of the bag main body 20 by injection molding to obtain a packaging bag 50. The reinforcing member 30 extends along the side portion of the bag body 20, and is formed in a columnar shape that covers the side portion of the bag body 20 from the outside.

As shown in FIG. 6, the reinforcing member 30 has a first wall portion 31 that covers one side of the side portion of the bag body 20, a second wall portion 32 that covers the other surface side of the side portion, and a side edge. It is formed in a U-shaped cross section (groove-shaped cross section) by the third wall portion 33 that covers it. The portion shown by the alternate long and short dash line in the bag body 20 of FIG. 6 means that the side sheet 11 and the bottom sheet 12 are adhered to each other.

As shown in FIG. 7, in the reinforcing member forming step, for example, a pair of molding dies composed of a lower molding die 40a and an upper molding die 40b, and forming a cavity C corresponding to the reinforcing member 30 between the two forming dies. Prepare 40. Then, the bag body 20 is sandwiched between the pair of molding dies 40 so that the side portion is inserted into the cavity C, and the molten resin is injected into the cavity C from the gate 41 provided in the molding dies 40. After that, the reinforcing member 30 is formed by solidifying.

By sequentially going through the laminating step, the bonding step, and the reinforcing member forming step, the packaging bag 50 including the bag main body 20 and the columnar reinforcing member 30 for reinforcing the side portion of the bag main body 20 is manufactured.

The bag body 20 of the packaging bag 50 has a bag shape by adhering a pair of side sheets 11 arranged to face each other and a bottom sheet 12 arranged between the side sheets 11 in a vertically folded state. I'm doing it. The reinforcing member 30 of the bag body 20 includes a first wall portion 31 that covers one side of the side portion of the bag body 20, a second wall portion 32 that covers the other side, and a first wall portion 31 and a second wall portion. A third wall portion 33 that connects the 32 and covers the side edge of the bag main body 20 is provided.

The bag body 20 of the packaging bag 50 includes a lower adhesive portion 21 to which the lower portion of the side sheet 11 and the bottom sheet 12 are adhered, and a side adhesive portion 25 to which the side portions of the side sheet 11 are adhered to each other. .. At the end of the upper edge 22 of the lower adhesive portion 21, an overlapping portion 23 extending so as to overlap the crease M of the bottom sheet 12 is provided. The side adhesive portion 25 is provided with a protruding portion 26 that is in contact with the overlapping portion 23 and projects toward the center.

Next, the operation of this embodiment will be described.
In the bonding step, the bag body 20 including the lower bonding portion 21 and the side bonding portion 25 is formed. The lower adhesive portion 21 is provided with an overlapping portion 23 that overlaps the crease M of the bottom sheet 12 and extends in the width direction as an end portion of the upper edge thereof. Further, the side adhesive portion 25 is provided with a protruding portion 26 that is in contact with the overlapping portion 23 of the lower adhesive portion 21 and projects toward the center.

By providing the protruding portion 26 on the side adhesive portion 25, it becomes difficult to open between the bottom sheets 12 when the reinforcing member 30 is injection-molded in the reinforcing member forming step, and the molten resin enters between the bottom sheets 12. Is suppressed. As a result, the molten resin is sufficiently filled between the side portion of the bag body 20 and the molding die 40, and the first wall portion 31 and the second wall portion 32 of the reinforcing member 30 can be appropriately formed.

Next, the effect of this embodiment will be described.
(1) The method for manufacturing the packaging bag 50 includes a laminating step of forming a laminated body 10 in which a bottom sheet 12 in a vertically folded state is arranged between a pair of side sheet 11s, and a bag-shaped bonding of the laminated body 10. The bag body 20 is provided with a bonding step for forming the bag body 20 and a reinforcing member forming step for forming the reinforcing member 30 on the side portion of the bag body 20 by injection molding.

The bag body 20 formed by the bonding step includes a lower bonding portion 21 in which the lower portion of the side sheet 11 and the bottom sheet 12 are bonded, and a side bonding portion 25 in which the side portions of the side sheet 11 are bonded to each other. ing. At the end of the upper edge 22 of the lower adhesive portion 21, an overlapping portion 23 extending so as to overlap the crease M of the bottom sheet 12 is provided. The side adhesive portion 25 is provided with a protruding portion 26 that is in contact with the overlapping portion 23 and projects toward the center.

According to the above configuration, when the reinforcing member 30 is injection-molded, it becomes difficult to open the space between the bottom sheets 12, and the molten resin is suppressed from entering between the bottom sheets 12. As a result, it is possible to suppress molding defects of the reinforcing member 30 in which the recess 65 shown in FIGS. 9 and 10B is formed.

Here, as another method of suppressing the above-mentioned dent 65, a through portion such as a through hole or a notch is provided in the bottom sheet 12, and the side portions of the bottom sheet 12 are adhered to each other through the through portion. It is possible to make it difficult to open. However, in the case of this method, a processing step for providing the penetrating portion on the bottom sheet 12 is required, so that the number of steps for manufacturing the packaging bag 50 increases. On the other hand, according to the above configuration, in the bonding step, the suppressing effect can be obtained only by adjusting the forming ranges of the lower bonding portion 21 and the side bonding portion 25, so that the number of steps for manufacturing the packaging bag 50 is obtained. Does not increase.

(2) The protruding portion 26 is located on the side edge side of the bag body 20 with respect to the end portion 23a on the central side of the overlapping portion 23.
According to the above configuration, when the contents contained therein are taken out from the opening of the upper edge portion of the bag main body 20, it is possible to prevent the contents from being caught by the protruding portion 26.

(3) The protruding portion 26 is formed so that the protruding length becomes shorter toward the upper side.
According to the above configuration, it is possible to suppress a decrease in the storage capacity of the bag body 20 due to the provision of the protruding portion 26.

(4) In the bonding step, the first region R1 is heat-welded and then the second region R2 is heat-welded. In the first region R1, the lower edge 10a of the laminated body 10, the side edges 10b on both sides, both ends are located above the crease M of the bottom sheet 12, and the central portion is located below the crease M. This is a region surrounded by an arcuate inner edge 10c whose central portion is recessed downward. The second region R2 is a region having a constant width extending from the upper end to the lower end along the side edges 10b on both sides of the laminated body 10.

According to the above configuration, when the reinforcing member 30 is injection-molded, the effect of suppressing the opening between the bottom sheets 12 can be obtained more remarkably.
In addition, this embodiment can be implemented by changing as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

-The shape of the protrusion 26 may be changed. For example, the protruding portion 26 may have the same protruding length in the vertical direction, or the protruding portion 26 may have a shorter protruding length toward the lower side. Further, the tip of the portion of the protruding portion 26 in contact with the overlapping portion 23 does not have to be located at the end portion 23a on the central side of the overlapping portion 23. However, from the viewpoint of suppressing the contents from being caught by the protruding portion 26 when the contents housed inside are taken out from the opening of the upper edge portion of the bag body 20, the tip of the portion of the protruding portion 26 in contact with the overlapping portion 23. Is preferably located closer to the side edge of the bag body 20 than the central end 23a of the overlapping portion 23.

-In the above embodiment, in the bonding step, the lower bonding portion 21 and the side bonding portion 25 are formed by bonding the first region R1 and then the second region R2, but each part in the bonding step. The bonding order of the above is not particularly limited. For example, the first region R1 may be bonded after the second region R2 is bonded, or the lower bonding portion 21 and the side bonding portion 25 may be bonded at the same time.

-The method of adhering the side sheet 11 and the bottom sheet 12 is not limited to heat welding. For example, it may be adhered using an adhesive. When bonding with an adhesive or the like, the side sheet 11 and the bottom sheet 12 having non-seal layers formed on both sides can also be used.

The width of the side adhesive portion 25 can be appropriately set according to the application of the packaging bag, etc., and the side adhesive portion 25 is partially wide or narrow in addition to the protruding portion 26. It may have a portion.

The configuration of the upper edge portion of the bag body 20 is not particularly limited. For example, the mouthpiece is inserted into the upper edge of the bag body 20, and the outer surface of the mouthpiece and the inner surface of the side sheet 11 are adhered to each other, and the inner surfaces of the side sheet 11 are adhered to each other to bond the upper edge of the bag body 20. The opening portion of the may be closed.

Next, the technical idea that can be grasped from the above-described embodiment and modification is described below.
(B) The lower adhesive portion is a method for manufacturing the packaging bag in which the side sheets are not adhered to each other.

(B) A method for manufacturing the packaging bag, wherein the protruding portion is located on the side edge side of the bag body with respect to the central end of the overlapping portion.
(C) In the bonding step, after the first region is bonded, the lower bonding portion and the side bonding portion are formed by bonding the second region, and the first region is the lower edge of the laminate. And the side edges on both sides, and the inner edge with a shape in which the central part is recessed downward so that both ends are located above the crease of the bottom sheet and the central part is located below the crease. The method for manufacturing the packaging bag, which is a region surrounded by, and the second region is a region having a constant width extending from the upper end to the lower end along the side edges on both sides of the laminated body.

M ... Fold, 10 ... Laminate, 11 ... Side sheet, 12 ... Bottom sheet, 20 ... Bag body, 21 ... Lower adhesive part, 22 ... Upper edge, 23 ... Overlapping part, 24 ... Arc part, 25 ... Side adhesive Part, 26 ... projecting part, 30 ... reinforcing member, 31 ... first wall part, 32 ... second wall part, 33 ... third wall part, 50 ... packaging bag.

Claims (2)

A bag body and a columnar reinforcing member for reinforcing the side portion of the bag body are provided.
The bag body has a bag shape by adhering a pair of side sheets arranged to face each other and a bottom sheet arranged between the side sheets in a vertically folded state.
The reinforcing member connects the first wall portion that covers one side of the side portion of the bag body, the second wall portion that covers the other surface side, the first wall portion, and the second wall portion. A method for manufacturing a packaging bag including a third wall portion that covers the side edge of the bag body.
A laminating step of forming a laminated body in which the bottom sheet in a vertically folded state is arranged between the pair of the side sheets.
An bonding step of adhering the laminate into a bag shape to form the bag body,
It is provided with a reinforcing member forming step of forming the reinforcing member on the side portion of the bag body by injection molding.
The bag body formed by the bonding step is
A lower adhesive portion to which the lower portion of the side sheet and the bottom sheet are adhered,
A side adhesive portion in which the side portions of the side sheet are adhered to each other is provided.
At the end of the upper edge of the lower adhesive portion, an overlapping portion extending so as to overlap the crease of the bottom sheet is provided.
A method for manufacturing a packaging bag, wherein the side adhesive portion is provided with a protruding portion that is in contact with the overlapping portion and projects toward the center. A bag body and a columnar reinforcing member for reinforcing the side portion of the bag body are provided.
The bag body has a bag shape by adhering a pair of side sheets arranged to face each other and a bottom sheet arranged between the side sheets in a vertically folded state.
The reinforcing member connects the first wall portion that covers one side of the side portion of the bag body, the second wall portion that covers the other surface side, the first wall portion, and the second wall portion. A packaging bag including a third wall portion that covers the side edge of the bag body.
The bag body
A lower adhesive portion to which the lower portion of the side sheet and the bottom sheet are adhered,
A side adhesive portion in which the side portions of the side sheet are adhered to each other is provided.
At the end of the upper edge of the lower adhesive portion, an overlapping portion extending so as to overlap the crease of the bottom sheet is provided.
A packaging bag characterized in that the side adhesive portion is provided with a protruding portion that is in contact with the overlapping portion and projects toward the center.