JP7565073B2 - Bottom-pasted bags and manufacturing method thereof - Google Patents

Description

Article 30, paragraph 2 of the Patent Act applies. September 15, 2020: Sold to Scholl Haven Starch Co., Ltd.

This invention relates to a bottom-attached bag with an inner patch and a method for manufacturing the same.

Patent Document 1 describes how a bottom-attached bag is made by folding the end of a flattened paper tube upright, then folding it down from the left and right to open the opening of the end, forming a roughly hexagon consisting of a pair of left and right triangular folds and a rectangular section between the folds, and then folding the top and bottom ends (top and bottom flaps) of this roughly hexagon inwards to close it. It also describes how an inner patch is used that is large and wider than the distance between the two fold lines that serve as the basis for folding the top and bottom flaps, and that spans the left and right folds, and how this inner patch is attached with a peelable adhesive.

In the above bottom-attached bag, the inner patch protrudes above and below the two fold lines, and these protruding portions are glued to the top and bottom flaps. This prevents the contents from leaking due to the two fold lines. Also, because the inner patch is attached with a peelable adhesive, it can be easily opened.

JP 2004-307008 A

The protruding portion of the inner patch is folded when the top and bottom flaps are folded back. When opening the package, this folded protruding portion needs to be unfolded when the top and bottom flaps are unfolded, but sometimes it peels off from the top and bottom flaps and remains folded. When this happens, a gap is created between the fold line and the inner patch, exposing the contents.

To prevent the protruding part of the inner patch from peeling off from the top and bottom flaps, it is possible to attach the inner patch to the top and bottom flaps with a non-peeling adhesive; however, in this case, pieces of paper may be produced when the inner patch is peeled off, which may contaminate the contents.

Therefore, the objective of the present invention is to provide a bottom-sealed bag that is both airtight and easy to open, and that can prevent contamination of the contents when opened, and a method for manufacturing the same.

The bottom-pasted bag 1 of the present invention is a bottom-pasted bag 1 in which the end of the tubular body 2 is raised and then folded down from the left and right to form a polygonal section 7 having a pair of left and right fold-in sections 5, 6 and a rectangular opening 3, the rectangular opening 3 is covered with an inner patch 11, and the top and bottom ends 8, 9 of the polygonal section 7 are folded inward along two fold lines (b, c) and glued to form a bottom end 19. One side of the inner patch 11 is attached to the pair of left and right fold-in sections 5, 6 and the top and bottom ends 8, 9 located outside the two fold lines (b, c) with a peelable adhesive G1, and the corners 12 on the other side of the inner patch 11 are non-adhesive sections E1 that are not glued to other parts.

In the above bottom-attached bag 1, it is preferable that the lower edge portion 13, which is located below the fold line (b) when the lower end portion 8 of the polygonal portion 7 is folded back, and the upper edge portion 14, which is located above the fold line (c) when the upper end portion 9 of the polygonal portion 7 is folded back, are non-adhesive portions E1 on the other surface of the inner patch 11.

It is also preferable that the non-adhesive portion E1 is composed of a non-coated portion E2 to which no adhesive is applied.

It is also preferable that both left and right ends of the fold line (b, c) are glued.

The method for manufacturing a bottom-attached bag of the present invention involves standing up the end of a tubular body 2, folding down the upright portion from the left and right to form a polygonal portion 7 having a pair of left and right fold-in portions 5, 6 and a rectangular opening 3, covering the rectangular opening 3 with an inner patch 11, and folding back and adhering the upper and lower ends 8, 9 of the polygonal portion 7 inward along two fold lines (b, c) to form a bottom end 19. One side of the inner patch 11 is then folded over to form a bottom end 19 by bonding the pair of left and right fold-in portions 5, 6 and the 2 The upper and lower ends 8, 9 located outside the fold lines (b, c) are attached with a peelable adhesive G1, and then adhesive G2 is applied to the upper and lower ends 8, 9 of the polygonal portion 7 and/or the parts that will face the upper and lower ends 8, 9 when the upper and lower ends 8, 9 of the polygonal portion 7 are folded back, avoiding the corners 12 on the other side of the inner patch 11 and the parts that will face the corners 12 when the upper and lower ends 8, 9 of the polygonal portion 7 are folded back, and the upper and lower ends 8, 9 are folded back and adhered to form the bottom end 19.

In the bottom-attached bag of the present invention, the corners on the other side of the inner patch, which are the starting points for peeling of the inner patch, are non-adhesive parts that do not adhere to other parts, so it is possible to prevent the corners from adhering to other parts (for example, the inner patches adhering to each other) and peeling off from the top and bottom ends, preventing unintended exposure of the contents and preventing contamination of the contents when opened. Also, because the inner patch is attached to a pair of left and right folds and to the top and bottom ends located outside the two fold lines with a peelable adhesive, it is possible to achieve both sealing and ease of opening.

When the lower edge portion of the other surface of the inner patch, which is located below the fold line when the lower end of the polygonal portion is folded back, and the upper edge portion, which is located above the fold line when the upper end of the polygonal portion is folded back, are non-adhesive portions, peeling of the inner patch can be further suppressed.

When the non-adhesive portion is composed of a non-coated portion to which no adhesive is applied, the non-adhesive portion can be provided at low cost.

If both the left and right ends of the fold line are glued, the sealing performance can be further improved.

In the method for manufacturing a bottom-sealed bag of the present invention, adhesive is applied to the upper and lower ends of the polygonal portion and/or the areas that will face the upper and lower ends when the upper and lower ends of the polygonal portion are folded back, avoiding the corners of the other side of the inner patch that are the starting point for peeling of the inner patch and the areas that will face the corners when the upper and lower ends of the polygonal portion are folded back, making it possible to manufacture at low cost a bottom-sealed bag that is sealable, easy to open, and can prevent contamination of the contents when opened.

FIG. 1 is a plan view showing one embodiment of a bottom-pasted bag of the present invention. FIG. FIG. FIG. FIG. FIG. FIG. FIG. 4 is a plan view showing the state in which the outer patch is attached. 1 is a schematic diagram showing an opening process. 11A to 11C are plan views showing the process of installing the valve.

Next, an embodiment of the bottom-pasted bag 1 of the present invention will be described with reference to the drawings. FIG. 1 shows one embodiment of the bottom-pasted bag 1 of the present invention. As shown in FIGS. 2 to 8, this bottom-pasted bag 1 is made by standing the end of a flat folded cylindrical body (paper tube) 2 along a first fold line a, folding down this standing part from the left and right to form a rectangular opening 3, covering the opening 3 with an inner patch 11, and folding back the top and bottom ends 8 and 9 of the opening 3 inward along a second fold line b and a third fold line c that are parallel to the first fold line a to form a bottom end 19, and then attaching an outer patch 20 to the bottom end 19.

To explain each step in detail, first, as shown in FIG. 2, the front side 2a of the kraft paper tube 2 near the end, which is folded at the left and right side lines 4, 4, is valley-folded at the first fold line a parallel to the end. Next, as shown in FIG. 3, the end side lines 4, 4 are folded from the left and right so as to overlap the first fold line a. At this time, mountain folds are made so that triangular folds 5, 6 are formed at both the left and right ends. As a result, the end of the paper tube 2 becomes a polygonal portion 7 having a pair of approximately triangular folds 5, 6 and an approximately rectangular opening 3 formed between the folds 5, 6, and having an approximately hexagonal shape (see FIG. 4A). In the following, of the polygonal portion 7, the approximately trapezoidal portion (lower end) below the second fold line b is referred to as the lower flap 8, and the approximately trapezoidal portion (upper end) above the third fold line c is referred to as the upper flap 9. When folded back inward, the lower flap 8 and the upper flap 9 overlap each other. In other words, the second fold line b and the third fold line c are spaced apart from the first fold line a so that the bottom flap 8 and the top flap 9 overlap. The portion of the opening 3 surrounded by the second fold line b and the third fold line c is called the inner surface forming portion 10 (see FIG. 4B). This inner surface forming portion 10 becomes part of the front surface 2a and the rear surface 2b of the bottom-sealed bag 1 after manufacture.

Next, as shown in FIG. 5, adhesive G1 is applied to the left and right fold-in portions 5, 6 and the top and bottom flaps 8, 9 in a manner that surrounds the inner surface forming portion 10 in a generally square shape (first application). The adhesive is usually applied using a plate that is set to match the application shape. However, it may also be applied with a brush, or discharged or sprayed from the tip of a nozzle. In other words, it is sufficient as long as the adhesive can be attached to the target surface.

The adhesive G1 is peelable. A peelable adhesive is an adhesive (glue) that has enough adhesive strength that the inner patch 11 and the paper tube 2 are not damaged (e.g., layers separate) and no fragments (paper pieces, fiber pieces) are generated when the inner patch 11 is peeled off from the paper tube 2. For example, it is a vinyl acetate resin emulsion adhesive or a vinyl acetate polymer water-based emulsion. The adhesive strength is, for example, 1.0 to 2.0 N/15 mm (measured in accordance with JIS Z 1711-1994 "8.4 Heat seal strength test").

The inner patch 11 is generally rectangular, with a left-right width W1 greater than the left-right width W3 of the generally rectangular opening 3, and a vertical width W2 greater than the distance W4 (see FIG. 6) between the second fold line b and the third fold line c. The inner patch 11 is attached so as to straddle the left and right folds 5, 6, and also the lower flap 8 and upper flap 9. As a result, the inner surface forming portion 10 is completely covered by the inner patch 11.

Next, as shown in FIG. 6, adhesive G2 is applied to the lower flap 8 and the upper flap 9 (second application). At this time, at least the corners (four corners) 12 on the front side (opposite the back side) of the inner patch 11 are made into non-adhesive parts E1 that are not adhered to other parts. Specifically, the corners 12 of the inner patch 11 are made into non-adhesive parts E2 to which adhesive G2 is not applied, and when the lower flap 8 or the upper flap 9 is folded back along the second fold line b or the third fold line c, the parts facing the corners 12 are also made into non-adhesive parts E2. To form the non-adhesive parts E2, adhesive G2 may be applied to the parts to be made into non-adhesive parts E2. In this embodiment, the lower side part 13 located below the second fold line b and the upper side part 14 located above the third fold line c of the inner patch 11 are made into non-adhesive parts E1. As shown in the figure, the four corners 12 are included in the lower edge portion 13 and the upper edge portion 14.

In addition, if the adhesive G2 is applied up to the edge of the inner patch 11, there is a possibility that the adhesive G2 will spread to the inner patch 11 side during adhesion. For this reason, a first margin M1 where the adhesive G2 is not applied is provided along the edge of the inner patch 11. This first margin M1 is provided to avoid the boundary B1 between the fold-in portions 5, 6 and the rectangular opening 3. This is to prevent leakage of the contents from the boundary B1 between the fold-in portions 5, 6 and the rectangular opening 3. In addition, a second margin M2 where the adhesive G2 is not applied is provided at the bottom end of the lower flap 8 and the top end of the upper flap 9. The second margin M2 functions as a gripping portion when the upper and lower flaps 8, 9 are unfolded.

The adhesive G2 used for attachment is peelable. It may be the same as the adhesive G1 used in the first application, or a different adhesive may be used. For example, to increase the adhesive strength between the lower flap 8 and the upper flap 9, a peelable adhesive with stronger adhesive strength may be used.

As shown in FIG. 6, adhesive G2 is also applied to a small piece portion 15 of the lower flap 8 that is separated by the second fold line b and the outer edge of the inner patch 11. Similarly, adhesive G2 is also applied to a small piece portion 16 of the upper flap 9 that is separated by the third fold line c and the outer edge of the inner patch 11. This causes both the left and right ends of the second fold line b and the third fold line c to be bonded together, further preventing leakage of the contents.

Next, as shown in FIG. 7, the lower flap 8 is folded inward along the second fold line b parallel to the edge of the paper tube 2, and is attached to the fold-in portions 5, 6 and the inner patch 11, while the upper flap 9 is folded inward along the third fold line c parallel to the edge of the paper tube 2, and is superimposed and attached to the surface of the previously folded lower flap 8. By folding the opening 3 at the end of the paper tube 2 in this manner, a long and thin approximately hexagonal surface is formed. Note that, of the long and thin approximately hexagonal surface, the small triangular portions 17, 18 at both the left and right ends will be located on the side of the bottom-pasted bag 1 when the contents are filled. Therefore, the approximately rectangular portion excluding the small triangular portions 17, 18 becomes the bottom end portion 19. Note that the above folding order is one example, and can be changed depending on the type of bag making machine, the position and shape of the valve (filling port), etc.

Next, adhesives G3a and G3b are applied to the outer patch 20 made of craft paper (third application). The outer patch 20 is then attached to the bottom end 19 to complete the bottom-attached bag 1 shown in FIG. 8.

The outer patch 20 is rectangular and has a length approximately equal to the length of the bottom end 19 in the longitudinal direction. A tear tape 21 is provided on the back side of the outer patch 20 (the side that contacts the bottom end 19) as tear tape means. The tear tape 21 is a synthetic resin tape that is provided over the entire longitudinal length of the outer patch 20, and when the outer patch 20 is attached to the bottom end 19, it is aligned along the longitudinal direction of the bottom end 19 and overlaps the edge of the upper flap 9 or is located in the vicinity of it.

The outer patch 20 is attached with a removable adhesive G3a and a non-removable adhesive G3b. Specifically, the non-removable adhesive G3b is applied to the top and bottom edges of the outer patch 20, and the removable adhesive G3a is applied to the other parts. This is to firmly connect the lower flap 8 and the upper flap 9 with the outer patch 20 to prevent unintentional opening, and to make it easy to peel off when the outer patch 20 is divided into upper and lower parts by the tear tape 21. No adhesive is applied to the tear tape 21. However, the removable adhesive G3a may be applied. In addition, the removable adhesive G3a is applied to at least one of the upper and lower parts around the tear tape 21 of the outer patch 20.

The non-peelable adhesive G3b is one that will damage the outer patch 20 or the paper tube 2 if an attempt is made to peel off the outer patch 20. For example, its adhesive strength is 3.0 N/15 mm or more (measured in accordance with JIS Z 1711-1994 "8.4 Heat seal strength test"), which is 1.5 to 3 times stronger than the peelable adhesives G1 and G2. The peelable adhesive G3a may be the same as the adhesives G1 and G2 used in the first and second applications, or a different one may be used.

The bottom-pasted bag 1 is filled with powders and granules such as flour, starch, carbon, and cement. The bottom-pasted bag 1 filled with the contents has a flat rectangular shape, and is transported and stored in a stack with the widest surface facing up and down (laid flat). In this case, the outer patch 20 is positioned on the side.

To open the bottom-attached bag 1, first grab the end of the tear tape 21 and pull it in the opposite direction to create a tear 13 in the outer patch 20 (see Figure 9A).

Next, the upper flap 9 and the lower flap 8 exposed from the tear 13 are opened in sequence (see Figures 9B and 9C). Only the upper and lower edges of the outer patch 20 are adhered with non-peelable adhesive G3b, and the other parts are adhered with peelable adhesive G3a, and the lower flap 8 and the upper flap 9 are adhered with peelable adhesive G2, so that it can be easily unfolded from the folded state. In addition, since the non-adhesive portion E1 is provided at the corner 12, which is the starting point for peeling of the inner patch 11, there is no problem that the lower edge portion 13 and the upper edge portion 14 peel off from the lower flap 8 and the upper flap 9, exposing the contents through the gap.

Next, as shown in FIG. 9D, the inner patch 11 is peeled off, and the left and right folds 5 and 6 (excluding the small triangular portions 17 and 18) are raised up, allowing the bottom-attached bag 1 to be completely opened.

In this way, the bottom-pasted bag 1 of the present invention does not expose the contents until the inner patch 11 is intentionally peeled off, so the contents do not leak out unintentionally, and fragments generated during opening do not contaminate the contents. In addition, because peelable adhesives G1, G2, and G3a are used, the bag can be easily opened by hand without the use of tools such as scissors or knives. The top and bottom edges of the outer patch 20 are adhered with non-peeling adhesive G3b, but because tear tape 21 is provided to separate the top and bottom edges, the bag can be easily opened without tools.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, the method of forming the non-adhesive portion E1 may include forming the non-applied portion E2 at the corner portion 12 or the upper and lower side portions 13, 14 of the inner patch 11 and at the portion facing the corner portion 12 or the upper and lower side portions 13, 14, or may include disposing a difficult-to-adhere component at the corner portion 12 or the upper and lower side portions 13, 14 of the inner patch 11 and/or at the portion facing the corner portion 12 or the upper and lower side portions 13, 14. For example, a release agent may be applied to the front side of the inner patch 11, or a layer of a difficult-to-adhere material such as silicone rubber, polypropylene, polyethylene, polyacetal, or fluororesin may be formed.

Also, adhesives G1, G2, G3a, and G3b may be applied to opposing (overlapping) sides. That is, adhesive G1 may be applied to the back side of the inner patch 11 (the side facing the fold-in portions 5, 6 and the top and bottom flaps 8, 9), adhesive G2 may be applied to the front side of the inner patch 11 or the bottom flap 8 after it is folded back, and adhesives G3a and G3b may be applied to the bottom end 19. Also, adhesives may be applied to both opposing sides.

In the above embodiment, the paper tube 2, the inner patch 11, and the outer patch 20 are made of kraft paper, but this is not limited to the above. Various materials can be used, such as synthetic resin sheets, laminated materials of paper and synthetic resin sheets, and polysand paper with a synthetic resin sheet sandwiched between two sheets of paper. Multiple sheets may also be used. The material of the tear tape 21 is not limited to synthetic resin, and various materials such as paper that is stronger than the outer patch 20 can be used, and it may even be thread or string. The tear tape 21 may be provided on the back side (bottom end 19 side) of the outer patch 20, or on the front side, or on both.

The other opening of the paper tube 2 (opposite the bottom end 19) is closed by folding it in the same way as the bottom end 19 and attaching the outer patch 20 (so-called double-bottom bag), but it may also be closed by sewing (so-called single-bottom bag). In addition, in the case of a double-bottom bag, a valve 22 for filling the contents may be provided. The valve 22 is manufactured by attaching the end of a rectangular paper such as craft paper to the other end to form a tube and flattening it by folding both sides. As shown in FIG. 10, the end of the paper tube 2 folded flat is glued to the triangular fold 5 by the first fold line a in a state where the rectangular opening 3 is opened. The valve 22 of the above configuration opens in the left and right directions in the figure, and after the opening 3 of the paper tube 2 is folded and closed at the second fold line b and the third fold line c to form the bottom end 19, the outer patch 20 is attached to the bottom end 19 to allow communication between the inside and outside of the bag. The contents are filled by inserting a nozzle into the valve 22. After filling the contents, the tip of the valve 22 is folded back and sealed by gluing or heat sealing.

The outer patch 20 may also be omitted. A non-peeling adhesive may also be used in the second application. The shape of the inner patch 11 is not limited to a substantially rectangular shape, but may also be a polygonal shape or one with rounded corners.

1 Bottom-pasted bag 2 Cylindrical body (paper tube)
2a Front surface 2b Rear surface 3 Opening 4 Side lines 5, 6 Triangular fold 7 Polygonal portion 8 Bottom end (bottom flap)
9 Top end (upper flap)
10 Inner surface forming portion 11 Inner patch 12 Corner portion 13 Lower side portion 14 Upper side portion 15, 16 Small piece portion 17, 18 Small triangular portion 19 Bottom end portion 20 Outer patch 21 Opening tape 22 Valve a First fold line b Second fold line c Third fold line B1 Boundary portion G1 between folded portion and opening Removable adhesive G2 Removable adhesive G3a Removable adhesive G3b Non-removable adhesive E1 Non-adhesive portion E2 Non-applied portion M1 First margin portion M2 Second margin portion W1 Left-right width W2 of inner patch Vertical width W3 of inner patch Left-right width W4 of opening Distance between second fold line and third fold line

Claims (5)

A bottom-attached bag in which an end of a tubular body is raised up and the raised portion is folded down from the left and right to form a polygonal portion having a pair of left and right fold-in portions and a rectangular opening, the rectangular opening is covered with an inner patch, and a bottom end is formed by folding back and adhering the top and bottom ends of the polygonal portion inward along two fold lines,
One surface of the inner patch is attached to the pair of left and right folded parts and the upper and lower ends located outside the two fold lines by a peelable adhesive,
The corners of the other surface of the inner patch are non-adhesive portions that are not adhered to other portions,
The bottom-pasted bag is coated with adhesive for folding back and bonding the upper and lower ends of the polygonal portion inward, so that a first margin portion where no adhesive is applied is provided along the edge of the inner patch, and the first margin portion is provided so as to avoid the boundary between the folded-in portion and the rectangular opening . The bottom-attached bag according to claim 1, in which the lower edge portion of the other surface of the inner patch, located below the fold line when the lower end of the polygonal portion is folded back, and the upper edge portion, located above the fold line when the upper end of the polygonal portion is folded back, are non-adhesive portions. The bottom-attached bag according to claim 1 or 2, in which the non-adhesive portion is composed of a non-coated portion to which no adhesive is applied. A bottom-attached bag according to any one of claims 1 to 3, in which both left and right ends of the fold line are glued. A method for manufacturing a bottom-pasted bag, comprising: standing an end of a tubular body, folding down the standing portion from the left and right to form a polygonal portion having a pair of left and right fold-in portions and a rectangular opening; covering the rectangular opening with an inner patch; and folding back and bonding the top and bottom ends of the polygonal portion inward along two fold lines to form a bottom end,
One side of the inner patch is attached to the pair of left and right folded parts and the upper and lower ends located outside the two fold lines with a peelable adhesive,
A method for manufacturing a bottom-sealed bag, comprising: applying adhesive to the upper and lower ends of the polygonal portion and/or the portions that will face the upper and lower ends when the upper and lower ends of the polygonal portion are folded back, avoiding the corners of the other side of the inner patch and the portions that will face the corners when the upper and lower ends of the polygonal portion are folded back, so that a first margin portion to which no adhesive is applied is provided along the edge of the inner patch, and so that the first margin portion is provided avoiding the boundary portion between the fold-in portion and the rectangular opening , and then folding back and bonding the upper and lower ends to form the bottom end.

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