Two-layer bag, its manufacturing method and manufacturing device, and bagged body

Abstract

To provide a double-layered bag with reduced possibility that a content erroneously enters between an inner layer and an outer layer.SOLUTION: A double-layered bag 81 has an inner layer 1B forming an inner bag and an outer layer 1A forming an outer bag, and the inner layer 1B and the outer layer 1A are bonded to each other only at a partial region. The double-layered bag 81 has a hollow body part 2 having an opening 2a at one end, with the other end closed. Notches 91b-98b are formed from an edge of the opening 2a toward a bottom part 3 at an inner hollow part formed of the inner layer 1B and an outer cylindrical part formed of the outer layer 1A which constitute the body part 2. Between the inner cylindrical part and the outer cylindrical part, a circumferential region R2 continuously rounding the body part 2 at a farther position from an edge of the opening 2a than any tip of the notches 91b-98b is bonded by an adhesive 22, and a region R82, which is arranged at a position nearer to the edge of the opening 2a than any tip of the notches 91b-98b so as to avoid any of the notches 91b-98b, is bonded by an adhesive 82.SELECTED DRAWING: Figure 23

Description

[Technical Field]

[0001] The present invention relates to a two-layer bag, a manufacturing method and device thereof, and a bagged product using the two-layer bag. [Background technology]

[0002] A two-layer bag has been known as a strong and flexible bag, having an inner layer forming an inner bag and an outer layer forming an outer bag, with the inner layer and the outer layer being bonded only in a partial region. This conventional two-layer bag has a cylindrical body portion with an opening at one end and a closed other end, and has a double structure consisting of an inner tubular portion formed by the inner layer and an outer tubular portion formed by the outer layer.

[0003] As an example of such a conventional two-layer bag, a multi-layer bag is disclosed in the following Patent Document 1. This multi-layer bag is made by stacking multiple rectangular sheet-like materials, joining two opposing edges together to form a tube, flattening the joined edges so that they are positioned almost in the center, and joining all of the materials together at one end of the tube to form the multi-layer bag, and then joining one or more lines of material from the side of the bag opposite the side that was joined together to form the tube, almost parallel to the side that was joined together to form the tube. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Jikko No. 57-34991 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional two-layer bag, the inner layer and the outer layer are bonded only at the body seal and the one or more adhesive strips near the opening, which means that the inner layer and the outer layer are separated by a relatively large distance near the opening, which can lead to the risk of contents accidentally getting between the inner and outer layers.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a two-layer bag in which the inner layer and the outer layer are less likely to separate near the opening, thereby reducing the risk of contents accidentally getting between the inner and outer layers, a manufacturing method and manufacturing device for the bag, and a bagged product using the two-layer bag. [Means for solving the problem]

[0007] The following embodiments are presented as means for solving the above problems. A two-layer bag according to a first embodiment has an inner layer forming an inner bag and an outer layer forming an outer bag, the inner layer and the outer layer being bonded only in a partial region, the bag having a tubular body portion with an opening at one end and a closed other end, the body portion having a double structure consisting of an inner tubular portion made of the inner layer and an outer tubular portion made of the outer layer, incisions are formed in the inner tubular portion and the outer tubular portion from an edge of the tubular portion corresponding to the edge of the opening toward the other end of the body, the partial region includes an opening-side region bonded with an adhesive, the opening-side region is positioned to avoid any of the incisions, the opening-side region is positioned so that the entire edge of the opening hits any point in the opening-side region when the edge of the opening is virtually moved toward the other end of the body, and a portion of the opening-side region is positioned closer to the edge of the opening than any tip of any of the incisions.

[0008] The incisions may be formed in the two-layer bag for various reasons. For example, when forming a square bottom using an incision, when the incision for forming the square bottom is formed on the bottom side, the incision may also be formed on the opening side of the adjacent two-layer bag that is produced in succession.

[0009] According to the first aspect, the partial region includes the opening side region, and the opening side region is positioned so that when the edge of the opening is virtually moved toward the other end of the body, the entire edge of the opening comes into contact with somewhere in the opening side region, so there is no risk of the contents accidentally getting between the inner layer and the outer layer further toward the bottom side (toward the other end of the body) than the opening side region.

[0010] Unlike the first embodiment, if the opening-side region is configured solely from a circumferential region that continuously encircles the body portion at a position farther from the edge of the opening toward the other end of the body portion than any of the incisions, the circumferential region is positioned further from the edge of the opening toward the other end of the body portion than any of the incisions, which limits how close the circumferential region can be to the edge of the opening. Therefore, if the opening-side region is configured solely from the circumferential region, there is a high risk of the contents being accidentally trapped between the inner layer and the outer layer between the circumferential region and the edge of the opening. However, according to the first embodiment, a portion of the opening-side region is positioned closer to the edge of the opening than the tips of any of the incisions, which reduces the risk of the contents being accidentally trapped between the inner layer and the outer layer compared to when the opening-side region is configured solely from the circumferential region. Furthermore, according to the first aspect, the opening side region avoids the incision, so even if the incision is formed after the adhesive is applied, there is no risk of the adhesive sticking to the blade forming the incision and causing problems, and even if the adhesive is applied after the incision is formed, there is no risk of the adhesive leaking from the incision to the back side of the application surface and causing problems.

[0011] Thus, according to the first aspect, even though the incisions are formed, it is possible to significantly reduce the risk of contents accidentally getting between the inner and outer layers, provided that there is no risk that adhesive will stick to the blades that form the incisions, causing problems during manufacturing, or that adhesive will get from the incisions to the back of the application surface and cause problems.

[0012] The two-layer bag according to the second aspect is the bag of the first aspect, wherein the opening side region includes a circumferential region that continuously circumferentially surrounds the body portion from the edge of the opening toward the other end of the body portion at a position farther than either of the incisions, and a region located between the edge of the opening and the circumferential region.

[0013] Although this second aspect is an example of the opening side region, the first aspect is not limited to this example.

[0014] A two-layer bag according to a third aspect is the bag of the second aspect, wherein the region located between the edge of the opening and the circumferential region is a region that intermittently circumferentially surrounds the body portion.

[0015] According to the third aspect, the region between the edge of the opening and the circumferential region is a region that intermittently circumferentially surrounds the body, and therefore the risk of the contents accidentally getting between the inner layer and the outer layer can be significantly reduced compared to when the region between the edge of the opening and the circumferential region is a small portion of the body in the circumferential direction. However, in the second aspect, the region between the edge of the opening and the circumferential region may be a small portion of the body in the circumferential direction.

[0016] The two-layer bag according to the fourth aspect is the bag according to any one of the first to third aspects, which does not have a heat-sealed adhesive portion. In the first to third aspects, the bag may not have a heat-sealed adhesive portion as in the third aspect, or may have a heat-sealed adhesive portion.

[0017] A two-layer bag according to a fifth aspect is the bag according to any one of the first to fourth aspects, further comprising a square bottom portion that closes the other end of the body portion.

[0018] In this fourth embodiment, a square-bottom bag is used as an example of the shape of the bag, although the first to fourth embodiments do not necessarily have to have a square bottom.

[0019] The two-layer bag according to the sixth aspect has an inner layer forming an inner bag and an outer layer forming an outer bag, and the inner and outer layers are bonded together only in a partial region. The two-layer bag has a tubular body with an opening at one end and a closed other end, and has a double structure consisting of an inner tubular portion made of the inner layer and an outer tubular portion made of the outer layer. Band-like regions extending in the lengthwise direction of the inner tubular portion are heat-sealed to each other so that the inner layer forms the inner tubular portion. The partial region includes a peripheral region that continuously surrounds the body near the edge of the opening and is bonded with an adhesive.

[0020] As far as the inventors know, there has been no prior two-layer bag in which band-like regions extending in the longitudinal direction of the inner tubular portion are heat-sealed together, and the partial region includes the circumferential region. This is presumably due to the circumstances described in the first comparative example below. As a result of research, the inventors found that the two-layer bag according to the sixth aspect can be realized by a manufacturing method according to the tenth aspect below, and thus invented the two-layer bag according to the sixth aspect.

[0021] According to the sixth aspect, although the band-shaped regions extending in the longitudinal direction of the inner tubular portion are heat-sealed to each other, the partial region includes the circumferential region, thereby reducing the risk of contents accidentally getting between the inner layer and the outer layer.

[0022] The two-layer bag according to the seventh aspect is the sixth aspect, wherein one surface of the inner layer is heat-sealable and the other surface of the inner layer is not heat-sealable (i.e., not heat-sealable), and a strip-shaped portion along one side of the inner layer extending in the length direction of the inner tubular portion is folded over so that the one surface is on the outside and the folded state is maintained by adhesive bonding, and the strip-shaped portion is heat-sealed to a strip-shaped region along the other side of the inner layer extending in the length direction of the inner tubular portion.

[0023] According to the seventh aspect, the inner layer can be pasted in an envelope-like manner instead of a butt-to-butt type.

[0024] The two-layer bag according to an eighth aspect is the bag according to the sixth or seventh aspect, further comprising a square bottom portion that closes the other end of the body portion.

[0025] In this eighth embodiment, a square-bottom bag is used as an example of the shape of the bag, although the sixth and seventh embodiments do not necessarily have to have a square bottom.

[0026] The bagged body according to the ninth aspect uses a two-layer bag according to any one of the first to eighth aspects, with the desired contents contained inside the inner bag and the opening closed.

[0027] The manufacturing method for a two-layer bag according to the tenth aspect is a manufacturing method for manufacturing a two-layer bag according to any one of the sixth to eighth aspects, in which the adhesive for bonding the circumferential region is applied to a first sheet forming a continuum of the outer layer, and the first and second sheets are guided so that the adhesive applied to the first continuous sheet does not transfer to the intended facing region of the second sheet forming the continuum of the inner layer until the intended facing region that will face the heater bar that performs the heat sealing has passed the point facing the heater bar.

[0028] According to the tenth aspect, the two-layer bag according to the sixth to eighth aspects can be manufactured without the inconveniences that arise when using the manufacturing apparatus shown in FIG. 16, which will be described later.

[0029] The two-layer bag manufacturing apparatus according to the 11th aspect is a two-layer bag manufacturing apparatus used to manufacture two-layer bags according to any one of the sixth to eighth aspects, and is equipped with an application unit that applies the adhesive that bonds the circumferential region to a first sheet that forms the continuous outer layer, and a guide unit that guides the first and second sheets so that the adhesive applied to the first continuous sheet does not transfer to the intended facing region of the second sheet that forms the continuous inner layer, until the intended facing region that will face the heater bar that performs the heat sealing has passed the point where it faces the heater bar.

[0030] According to the eleventh aspect, the two-layer bag according to the sixth to eighth aspects can be manufactured without the inconveniences that arise when using the manufacturing apparatus shown in FIG. 16, which will be described later. [Effects of the Invention]

[0031] According to the present invention, it is possible to provide a two-layer bag in which the inner layer and the outer layer are less likely to separate near the opening, thereby reducing the risk of contents accidentally getting between the inner and outer layers, a manufacturing method and manufacturing device for the bag, and a bagged product using the two-layer bag. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a schematic perspective view showing a state in which the opening of a two-layer bag according to a first embodiment of the present invention is opened to a moderate degree. [Figure 2] 2 is a schematic perspective view showing the two-layer bag shown in FIG. 1 with the opening completely opened. FIG. [Figure 3] 2A and 2B are a schematic front view and a schematic right side view showing the flattened state of the two-layer bag shown in FIG. 1. [Figure 4]FIG. 2 is a schematic cross-sectional view taken along line AA' in FIG. [Figure 5] FIG. 5 is a schematic enlarged cross-sectional view of a portion B in FIG. 4. [Figure 6] FIG. 2 is a schematic cross-sectional view taken along line CC' in FIG. [Figure 7] FIG. 5 is a schematic enlarged cross-sectional view of a portion D in FIG. 4. [Figure 8] 2 is a schematic development view showing the outer layer of the two-layer bag shown in FIG. 1. [Figure 9] FIG. 2 is a schematic development view showing the inner layer of the two-layer bag shown in FIG. [Figure 10] 2A and 2B are a schematic side view and a schematic plan view showing an example of a two-layer bag manufacturing apparatus used to manufacture the two-layer bag shown in FIG. 1. [Figure 11] 11A and 11B are a schematic enlarged side view and a schematic enlarged plan view showing the vicinity of the heater bar in FIG. 10. [Figure 12] 2 is a schematic rear view showing the process of forming the bottom of the two-layer bag shown in FIG. 1. [Figure 13] 13 is a schematic rear view showing the process of forming the bottom of the two-layer bag shown in FIG. 1 after the state shown in FIG. 12. [Figure 14] 14 is a schematic rear view showing the process of forming the bottom of the two-layer bag shown in FIG. 1 after the state shown in FIG. 13. [Figure 15] 2 is a schematic rear view showing the state after the formation of the bottom of the two-layer bag shown in FIG. 1 has been completed. [Figure 16] 11A and 11B are a schematic side view and a schematic plan view showing a manufacturing apparatus according to a comparative example to be compared with the manufacturing apparatus shown in FIG. 10. [Figure 17] 17A and 17B are a schematic enlarged side view and a schematic enlarged plan view showing an example of the state in the vicinity of the heater bar in FIG. 16. [Figure 18] 17A and 17B are a schematic enlarged side view and a schematic enlarged plan view showing another example of the state in the vicinity of the heater bar in FIG. 16. [Figure 19] 2 is a schematic perspective view showing a state in which an opening of a two-layer bag according to a first comparative example, which is compared with the two-layer bag shown in FIG. 1, is opened to a moderate degree. FIG. [Figure 20]FIG. 20 is a schematic perspective view showing the two-layer bag shown in FIG. 19 with the opening completely opened. [Figure 21] FIG. 20 is a schematic cross-sectional view taken along line EE' in FIG. [Figure 22] FIG. 22 is a schematic enlarged cross-sectional view of a portion F in FIG. 21. [Figure 23] FIG. 10 is a schematic perspective view showing a state in which the opening of a two-layer bag according to a second embodiment of the present invention is opened to a moderate degree. [Figure 24] FIG. 24 is a schematic perspective view showing the two-layer bag shown in FIG. 23 with the opening completely opened. [Figure 25] 24A and 24B are a schematic front view and a schematic right side view showing the flattened state of the two-layer bag shown in FIG. 23. [Figure 26] FIG. 24 is a schematic cross-sectional view taken along line GG' in FIG. 23. [Figure 27] FIG. 24 is a schematic cross-sectional view taken along line HH' in FIG. 23. [Figure 28] FIG. 24 is a schematic cross-sectional view taken along line II' in FIG. 23. [Figure 29] FIG. 24 is a schematic development view showing the outer layer of the two-layer bag shown in FIG. 23. [Figure 30] FIG. 24 is a schematic development view showing the inner layer of the two-layer bag shown in FIG. 23. [Figure 31] 24A and 24B are a schematic side view and a schematic plan view showing an example of a two-layer bag manufacturing apparatus used to manufacture the two-layer bag shown in FIG. 23. [Figure 32] 32 is a schematic plan view showing a part of a continuous sheet of the outer layer in FIG. 31. FIG. [Figure 33] 32 is a schematic plan view showing a part of a continuous sheet of the inner layer in FIG. 31. FIG. [Figure 34] 24 is a schematic rear view showing the process of forming the bottom of the two-layer bag shown in FIG. 23. [Figure 35] 35 is a schematic rear view showing the process of forming the bottom of the two-layer bag shown in FIG. 23 after the state shown in FIG. 34. [Figure 36] 36 is a schematic rear view showing the process of forming the bottom of the two-layer bag shown in FIG. 23 after the state shown in FIG. 35. [Figure 37]24 is a schematic rear view showing the state after the formation of the bottom of the two-layer bag shown in FIG. 23 has been completed. [Figure 38] FIG. 24 is a schematic perspective view showing a state in which the opening of a two-layer bag according to a second comparative example, which is compared with the two-layer bag shown in FIG. 23, is opened to a moderate degree. [Figure 39] 10A to 10C are partially enlarged schematic front views showing examples of patterns in the region on the opening side that is bonded with an adhesive. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, a two-layer bag according to the present invention, a manufacturing method and manufacturing apparatus thereof, and a bagged product using the two-layer bag will be described with reference to the drawings.

[0034] [First embodiment]

[0035] FIG. 1 is a schematic perspective view of a two-layer bag 1 according to a first embodiment of the present invention, with the opening 2a moderately opened. FIG. 2 is a schematic perspective view of the two-layer bag 1 shown in FIG. 1, with the opening 2a fully opened. FIG. 3(a) is a schematic front view of the two-layer bag 1 shown in FIG. 1 in a flattened state. FIG. 3(b) is a schematic right side view of the two-layer bag 1 shown in FIG. 1 in a flattened state. Note that FIG. 3(b) does not show the right side portion 13 that forms the gusset. FIG. 4 is a schematic cross-sectional view taken along line A-A' in FIG. 1. FIG. 5 is a schematic enlarged cross-sectional view of portion B in FIG. 4. FIG. 6 is a schematic cross-sectional view taken along line C-C' in FIG. 1. FIG. 7 is a schematic enlarged cross-sectional view of portion D in FIG. 4. FIG. 8 is a schematic development of the outer layer 1A of the two-layer bag 1 shown in FIG. 1. FIG. 9 is a schematic development of the inner layer 1B of the two-layer bag 1 shown in FIG. 1.

[0036] In the following explanation, the front side of the paper in Fig. 1 will be referred to as the front side or front face side, and the back side of the paper in Fig. 1 will be referred to as the rear side or rear face side, but the reverse is also possible. Regarding "front" and "rear," which side is the "front" and which side is the "rear" are not fixedly determined, and when "front" refers to one side, "rear" means the opposite side.

[0037] The two-layer bag 1 according to this embodiment has a cylindrical body 2 with an opening 2a at one end (the upper end in FIG. 1) and a closed other end (the lower end in FIG. 1). The two-layer bag 1 according to this embodiment has a square bottom 3 that closes the lower end of the body 2, making it a square-bottom bag. However, the two-layer bag according to the present invention does not necessarily have to have a square bottom, and is not limited to square-bottom bags. Furthermore, the two-layer bag according to the present invention does not necessarily have a gusset portion (described later).

[0038] In this embodiment, the body 2 has a front portion 11, a back portion 12, and side portions 13, 14 forming gusset portions, and is configured in a rectangular tube shape. Fold lines 13a-13d are formed on the right side 13 of the two-layer bag 1, and fold lines (not shown) similar to the fold lines 13a-13d are formed on the left side 14 of the two-layer bag 1, allowing the two-layer bag 1 to be folded flat as shown in FIG. 3. In this flat state, the opening 2a is closed. In the example shown in FIG. 3, the square bottom portion 3 is folded toward the back portion 12, but the square bottom portion 3 may also be folded toward the front portion 11. This also applies to FIG. 25, which will be described later.

[0039] 1 to 3 show a single-layer bag, but as shown in FIGS. 4 to 9, the two-layer bag 1 of this embodiment is a two-layer bag having an inner layer 1B forming an inner bag and an outer layer 1A forming an outer bag, with the inner layer 1B and the outer layer 1A bonded only in a partial region. The body 2 of the two-layer bag 1 has a double structure consisting of an inner tubular portion made of the inner layer 1B and an outer tubular portion made of the outer layer 1A. In this embodiment, as shown in FIGS. 1, 2, and 4 to 7, the inner tubular portion made of the inner layer 1B and the outer tubular portion made of the outer layer 1A are bonded with adhesive 22 only in a circumferential region R2 that continuously wraps around the body 2 near the edge of the opening 2a, and the inner layer 1B and the outer layer 1A are not bonded in other locations of the body 2. As described above, in this embodiment, the partial region includes a surrounding region R2 that continuously surrounds the body portion 2 and is bonded with adhesive 22 at a position close to the edge of the opening 2a.

[0040] The outer layer 1A is composed of a rectangular sheet when unfolded as shown in Fig. 8, and has a layer structure of one or more layers (not shown). The inner layer 1B is also composed of a rectangular sheet when unfolded as shown in Fig. 9, and has a layer structure of one or more layers (not shown). In this embodiment, one surface of the inner layer 1B (the surface on the far side of the paper in Fig. 9, i.e., the surface that mainly becomes the inside of the two-layer bag 1) is heat-sealable, and the other surface of the inner layer 1B (the surface on the near side of the paper in Fig. 9, i.e., the surface that mainly becomes the outside of the two-layer bag 1) is not heat-sealable.

[0041] The outer layer 1A can be a single-layer sheet made of one-sided glossy bleached kraft paper, with the side facing the page in Figure 8 (i.e., the side that forms the outside of the two-layer bag 1) being white. The inner layer 1B can be, for example, a four-layer sheet made of polyethylene / aluminum / polyethylene / unbleached kraft paper layered in this order from the one side, or a two-layer sheet made of polyethylene / unbleached kraft paper layered in this order from the one side. However, in the present invention, the outer layer 1A and the inner layer 1B are not limited to these examples and can be changed as appropriate depending on the contents to be stored.

[0042] In Figure 8, the mountain fold lines of the outer layer 1A are indicated by dashed lines, and the valley fold lines of the outer layer 1A are indicated by broken lines. As shown in Figure 8, the outer layer 1A has a portion 2A that becomes the outer tubular portion that forms the body 2 of the two-layer bag 1, and a portion 3A that forms the square bottom 3. The left side of the outer layer 1A in Figure 8 corresponds to the edge of the opening 2a of the two-layer bag 1. Of the portion 2A, a portion 11A forms the front portion 11 of the two-layer bag 1, a portion 12A forms the back portion 12, a portion 13A forms the right portion (gore portion) 13, and a portion 14A forms the left portion (gore portion) 14. A portion 1Aa in the band-shaped region along the bottom side of the outer layer 1A in Figure 8 corresponds to the glue tab.

[0043] In Fig. 8, a strip-shaped region R1 on the far side of the paper, extending along the upper edge of the outer layer 1A near the upper edge, is a region to which adhesive 21 is applied. As shown in Figs. 4 and 6, this adhesive 21 bonds the strip-shaped region R1 of the outer layer 1A to the portion 1Aa, forming the outer tubular portion. In Fig. 8, a strip-shaped region R2 on the far side of the paper, extending along the left edge of the outer layer 1A near the left edge, corresponds to the circumferential region R2 in Figs. 1 and 2, and is a region to which the adhesive 22 is applied. In Fig. 8, scattered regions R3 on the far side of the paper, arranged near the left edge of the outer layer, are a region to which adhesive 23 is applied, and the adhesive 23 bonds the inner layer 1B and the outer layer 1A at the corner base 3. The partial region also includes this region R3.

[0044] In Figure 9, the mountain fold lines of the inner layer 1B are indicated by dashed lines, and the valley fold lines of the inner layer 1B are indicated by broken lines. As shown in Figure 8, the inner layer 1B has a portion 2B that becomes the inner tubular portion that constitutes the body 2 of the two-layer bag 1, and a portion 3B that constitutes the square bottom portion 3. The left side of the inner layer 1B in Figure 9 corresponds to the edge of the opening 2a of the two-layer bag 1. Of the portion 2B, a portion 11B constitutes the front portion 11 of the two-layer bag 1, a portion 12B constitutes the back portion 12, a portion 13B constitutes the right portion (gore portion) 13, and a portion 14B constitutes the left portion (gore portion) 14. The strip-shaped portion 1Ba along the bottom side of the inner layer 1B in Figure 9 corresponds to the strip-shaped portion along one side of the inner layer 1B extending in the length direction of the inner tubular portion, and corresponds to the folded portion that is folded over to overlap the adjacent strip-shaped region 1Bb. 9, a thin strip-like region on the front side of the paper in Fig. 9 that extends along the lower edge of the inner layer 1B in Fig. 9 is an area to which adhesive 24 is applied. As shown in Figs. 4 to 7, this adhesive 24 keeps the strip-like portion 1Ba folded over the strip-like region 1Bb.

[0045] The heat-sealable region of the strip-shaped portion 1Bc extending along the upper edge of the inner layer 1B in Fig. 9, at the rear side of the paper in Fig. 9, is heat-sealed to the heat-sealable surface of the strip-shaped portion 1Ba, which is kept folded over the strip-shaped region 1Bb, with adhesive 24, to form an inner tubular portion, as shown in Fig. 4 and Fig. 6. In Fig. 4 and Fig. 6, the heat-sealed point between the strip-shaped portion 1Bc and the folded-over strip-shaped portion 1Ba is indicated by the reference numeral 25.

[0046] Figure 10(a) is a schematic side view showing an example of a two-layer bag manufacturing apparatus (bag making machine) 31 used to manufacture the two-layer bag 1 shown in Figure 1. In Figure 10(a), thick dashed lines indicate the path of the continuously transported outer layer sheet 1A', and thick solid lines indicate the path of the continuously transported inner layer sheet 1B'. Figure 10(b) is a schematic plan view showing some elements 43, 52, and 53 of the manufacturing apparatus 31, as well as the outer layer sheet 1A' and inner layer sheet 1B'.

[0047] The manufacturing apparatus 31 includes a sheet supply section 32 , a folding and coating section 33 , a cylindrical forming and heat sealing section 34 , a cutting section 35 , a bottom folding section 36 , and an accumulation section 37 .

[0048] The sheet supply unit 32 supports an outer layer sheet roll 1A" around which an outer layer sheet (first sheet) 1A' as a raw sheet is wound, and an outer layer sheet roll 1A" around which an inner layer sheet (second sheet) 1B' as a raw sheet is wound, and unwinds the outer layer sheet 1A' from the outer layer sheet roll 1A" and unwinds the inner layer sheet 1A' from the inner layer sheet roll 1B", and supplies them to be transported in the transport direction X. At this time, the sheet supply unit 32 supplies the outer layer sheet 1A' and the inner layer sheet 1B' so that the inner layer sheet 1B' is overlapped on the outer layer sheet 1A', with them shifted by a predetermined distance in the lateral direction (direction perpendicular to the transport direction X).

[0049] The outer layer sheet 1A' corresponds to a continuum (first sheet forming a continuum of outer layers 1A) in which the outer layers 1A shown in Figure 8 are successively connected in the transport direction X. However, in Figure 10(b), the state from the outer layer sheet roll 1A" to the guide roller 41 corresponds to the outer layer 1A shown in Figure 8 being reversed from side to side. Therefore, the front side of the paper in Figure 10(b) corresponds to the back side of the paper in Figure 8.

[0050] The inner layer sheet 1B' corresponds to a continuation of the inner layer 1B shown in FIG. 9 in the conveying direction X (a second sheet forming a continuation of the inner layer 1B). 9. Therefore, in this state, the surface of the inner layer sheet 1B' facing the front side of the paper in FIG. 10(b) is heat-sealable, and the surface of the inner layer sheet 1B' facing the rear side of the paper in FIG. 10(b) is not heat-sealable. The inner layer sheet 1B' overlaps the outer layer sheet 1A' on the front side of the paper in FIG. 10(b). The outer layer sheet 1A' and the inner layer sheet 1B' are shifted laterally by the specified distance in order to align the lateral positions of the portion 11A of the outer layer 1A that constitutes the front surface portion 11 in FIG. 8 and the portion 11B of the inner layer 1B that constitutes the front surface portion 11 in FIG.

[0051] As shown in Figure 10, the folding and application section 33 includes guide rollers 41, 42, 44, 45, 46, and 51, an application nozzle 43 that applies adhesive 24 to region R4 of the inner layer 1B in Figure 9, a folding mechanism (not shown) that folds back the strip portion 1Ba along the lower edge of the inner layer 1B in Figure 9 so that it overlaps the strip region 1Bb, an application device that applies adhesives 22 and 23 to regions R2 and R3 of the outer layer 1A in Figure 8, respectively, and an application nozzle 52 that applies adhesive 21 to region R1 of the outer layer 1A in Figure 8. The application device that applies adhesives 22 and 23 to regions R2 and R3 of outer layer 1A in Figure 8, respectively, includes a container 47 that contains adhesive to become adhesives 22 and 23, a take-out roller 48 that takes the adhesive from container 47, and an application roller 49 made of rubber or the like that applies the adhesive taken out by the take-out roller 48 to outer layer sheets 1A'R22 and R23 that pass between it and a receiving roller 50.

[0052] 10, the inner layer sheet 1B' has the adhesive 24 applied to region R4 by the application nozzle 43, then the strip portion 1Ba is folded back, and then it leaves the folding and application section 33 and enters the tubular forming and heat sealing section 34. On the other hand, the outer layer sheet 1A' has the adhesives 22 and 23 applied to regions R2 and R3 by the application roller 49, then the adhesive 24 is applied to region R1 by the application nozzle 52, and then it leaves the folding and application section 33 and enters the tubular forming and heat sealing section 34.

[0053] The inner layer sheet 1B' remains completely flat until the strip-shaped portion 1Ba is folded back, and after the strip-shaped portion 1Ba is folded back, it remains flat in that folded state until it passes the guide roller 45. The outer layer sheet 1A' remains completely flat until it passes the guide roller 52. In this manufacturing apparatus 31, the guide rollers 41, 42, 44, 45, 46, 51, etc., which serve as guide members, allow the inner layer sheet 1B' and the outer layer sheet 1A' to be completely separated without contact from the guide roller 41 to position P within the cylindrical forming / heat sealing section 34.

[0054] The cylindrical forming and heat sealing section 34 forms the inner layer sheet 1B' and the outer layer sheet 1A' into a cylindrical shape and folds them to complete the bonding of each part with adhesives 21, 22, and 23. The cylindrical forming and heat sealing section 34 has a forming member for performing the above-mentioned forming, but this is not shown. The cylindrical forming and heat sealing section 34 has a heater bar 53, which heat seals the cylindrically folded inner layer sheet 1B' between the strip-like portions 1Ba and 1Bc in Figure 9 (see also the heat-sealed portion 25 in Figures 4 to 7). The heat sealing process is shown in Figure 11.

[0055] Figure 11(a) is a schematic enlarged side view showing the vicinity of the heater bar 53 in Figure 10. Figure 11(b) is a schematic enlarged plan view showing the vicinity of the heater bar 53 in Figure 10. In Figure 11(b), R53 indicates the region of the inner layer sheet 1B' that will face the heater bar 53 as it is transported, and R53' indicates the region of the inner layer sheet 1B' that has passed the point facing the heater bar 53. As shown in Figure 11(a), the heater bar 53 is slightly inclined so that the outlet end (the lower left end in Figure 11(a)) comes into contact with the inner layer sheet 1B' and the inlet end leaves a slight gap between it and the inner layer sheet 1B'.

[0056] From position P in Figure 10(a) onward, the cylindrical forming / heat sealing section 34 maintains a state in which portion 11B of the inner layer sheet 1B' (Figure 9) is in contact with and overlaps portion 11A of the outer layer sheet 1A' (Figure 8), and both sides of portion 11B of the inner layer sheet 1B' are raised to form a cylindrical shape, while both sides of portion 11A of the outer layer sheet 1A' are raised to form a cylindrical shape. At this time, the cylindrical folding of the inner layer sheet 1B' is completed before the inner layer sheet 1B' reaches the heater bar 53. Meanwhile, portions 12A and the like of the outer layer sheet 1A' (Figure 8) are not yet overlapped with the inner layer sheet 1B' until they pass through the heater bar 53, as shown in Figure 11, but after passing through the heater bar 53, they overlap with the inner layer sheet 1B' and are completely formed into a cylindrical shape. This ensures that in this manufacturing apparatus 31, the adhesive 22 applied to the region R1 of the outer sheet 1A' by the application roller 49 does not transfer to the intended facing region R53 of the inner sheet 1B' on the top surface (including the intended facing region R53) of the cylindrically folded inner sheet 1B' until it has passed the point facing the heater bar 53. However, to ensure this, if necessary, a guide member (for example, a thin metal wire such as a wire with a certain degree of rigidity; not shown) may be used to guide one or both of the outer layer sheet 1A' and the inner layer sheet 1B' so that the inner layer sheet 1B' forming the top surface of the cylindrically folded inner layer sheet 1B' does not come into contact with the region R1 of the outer layer sheet 1A'.

[0057] The outer layer sheet 1A' is also formed into a complete cylindrical shape through the tubular forming / heat sealing section 34, passing through the heater bar 53, and the outer layer sheet 1A' and the inner layer sheet 1B' as a whole form a complete cylindrical body. This cylindrical body then passes through guide rollers 54 and is cut into cylindrical bodies 1' for one two-layer bag 1 by the cutting section 35. One end of each cylindrical body 1' for one two-layer bag 1 is folded by the bottom folding section 36 as shown in Figure 12 (the folded state during the formation of the square bottom 3). The cylindrical bodies 1' in the folded state shown in Figure 12 are accumulated in the accumulation section 37.

[0058] The cylindrical body 1' shown in Fig. 12 accumulated in the accumulation section 37 is a semi-finished product of the two-layer bag 1, but will be the product of the manufacturing apparatus 31. The manufacturing apparatus 31 can be realized, for example, by modifying a part of a known bag-making machine (for example, by adding or changing the position of guide rollers or adding the metal wire rods described above to guide the inner layer sheet 1B' and the outer layer sheet 1A' so that the adhesive 21 applied to the region R2 of the outer layer sheet 1A' does not transfer to the intended facing region R53 of the inner layer sheet 1B' that will face the heater bar 53 until the intended facing region R53 has passed the point facing the heater bar 53).

[0059] Fig. 12 is a schematic rear view showing the process of forming the bottom part 3 of the two-layer bag shown in Fig. 1. Fig. 13 is a schematic rear view showing the process of forming the bottom part 3 of the two-layer bag 1 shown in Fig. 1 after the state shown in Fig. 12. Fig. 14 is a schematic rear view showing the process of forming the bottom part 3 of the two-layer bag 1 shown in Fig. 1 after the state shown in Fig. 13. Fig. 15 is a schematic rear view showing the state after formation of the bottom part 3 of the two-layer bag 1 shown in Fig. 1 has been completed.

[0060] The cylindrical body 1' shown in Fig. 12 is folded as shown in Fig. 13 by a known bottom forming device (not shown), and an area R61 in the figure is heat-sealed, and then folded as shown in Fig. 14, and a bottom sheet 3a made of paper or the like is attached as shown in Fig. 15. This completes the two-layer bag 1 shown in Fig. 1. The manufacturing device 31 shown in Fig. 10 and the bottom forming device may be integrated to form a manufacturing device that performs all steps continuously.

[0061] The two-layer bag 1 according to this embodiment is manufactured by, for example, a bag manufacturer and supplied to a manufacturer of the contents, who places the desired contents into the body 2 through the opening 2a at the top of the body 2, and then closes the opening 2a to complete the bag. Any method can be used to close the opening 2a, but one method that can be used is to fold both side sections 13, 14 together to flatten the opening 2a, then roll the opening 2a and glue predetermined locations together with an adhesive to maintain the rolled state. The contents are not limited in any way and may be, for example, pesticides, food, medicines, powders, liquids, solids, etc.

[0062] In the two-layer bag 1 of this embodiment, although the band-shaped regions 1Ba, 1Bc extending in the longitudinal direction of the inner tubular portion made of the inner layer sheet 1B' are heat-sealed to each other, they are bonded with adhesive 22 in the circumferential region R2 that continuously circumferentially surrounds the body portion 2 at a position close to the edge of the opening 2a, thereby reducing the risk of contents accidentally getting between the inner and outer layers.

[0063] Figure 16(a) is a schematic side view showing a comparative example of a manufacturing apparatus 61, which is compared with the manufacturing apparatus 31 shown in Figure 10, and corresponds to Figure 10(a). Figure 16(b) is a schematic plan view showing some elements 43, 52, and 53 of the manufacturing apparatus 61, as well as the outer layer sheet 1A' and inner layer sheet 1B', and corresponds to Figure 10(b). In Figure 16, elements that are the same as or correspond to those in Figure 10 are designated by the same reference numerals, and redundant explanations will be omitted.

[0064] The manufacturing apparatus 61 shown in Figure 16 differs from the manufacturing apparatus 31 shown in Figure 10 mainly in that the guide roller 51 is removed, and the flat outer layer sheet 1A' after the adhesive 22 has been applied to region R2 by the application roller 49 is also guided to the guide roller 45, and on the guide roller 45, the flat outer layer sheet 1A' and the flat inner layer sheet 1B' after the strip portion 1Ba has been folded back come into contact and are temporarily overlapped, and that an application nozzle 52 that applies adhesive 21 to region R1 of the outer layer 1A is positioned near the guide roller 45.

[0065] In the manufacturing apparatus 61 shown in Fig. 16, the flat outer layer sheet 1A' after adhesive 22 has been applied to region R2 by the application roller 49 is brought into contact with the flat inner layer sheet 1B' after the strip portion 1Ba has been folded back, and the flat outer layer sheet 1A' is then superimposed on the guide roller 45. The entire area of ​​the folded flat inner layer sheet 1B' that overlaps region R2 of the outer layer sheet 1A' on the guide roller 45 becomes an adhesive-transferable region R2' to which the adhesive 22 applied to region R2 can be transferred. As shown in Fig. 17(b), this adhesive-transferable region R2' also includes the upper surface of the cylindrically folded inner layer sheet 1B' (the surface facing the page in Fig. 17(b)).

[0066] Figure 17(a) is a schematic enlarged side view showing an example of the state near heater bar 53 in Figure 16, and corresponds to Figure 11(a). Figure 17(b) is a schematic enlarged plan view showing an example of the state near heater bar 53 in Figure 16, and corresponds to Figure 11(b). In Figure 17, elements that are the same as or correspond to elements in Figure 11 are given the same reference numerals, and redundant explanations will be omitted.

[0067] Therefore, as shown in Figure 17(b), part of the adhesive-transferable region R2' overlaps with the intended facing region R53 that will face the heater bar 53. As shown in Figure 17(a), if adhesive 22' resulting from the transfer of adhesive 22 is present in this overlapping region, this adhesive 22' will accumulate in the gap between the inner layer sheet 1B' and the heater bar 53 and be pushed out to the tip of the heater bar 53, as shown in Figure 17, causing problems with the two-layer bag 1. These problems may include the adhesive 22' forming clumps and being mixed into the two-layer bag 1, the inner layer sheet 1B' being rubbed and damaged or torn, or the adhesive being scraped off from the overlapping region, resulting in no adhesion between the inner layer 1B and the outer layer 1A in that region.

[0068] To avoid this problem when using the manufacturing apparatus 61 shown in FIG. 16, it is necessary to remove a portion of the region R2 of the outer layer sheet 1A' to which the adhesive 22 is applied by the application roller 49 so that the adhesive-transferable region R2' does not overlap with the intended facing region R53, as shown in FIG. 18. In this case, the transferred adhesive 22, i.e., the adhesive 22', is not present in the intended facing region R53, and the above-mentioned problem does not occur. FIG. 18(a) is a schematic enlarged side view showing another example of the state near the heater bar 53 in FIG. 16, and corresponds to FIGS. 11(a) and 17(a). FIG. 18(b) is a schematic enlarged plan view showing another example of the state near the heater bar 53 in FIG. 16, and corresponds to FIGS. 11(b) and 17(b). In FIG. 18, elements that are the same as or correspond to those in FIGS. 11 and 17 are designated by the same reference numerals, and redundant explanations will be omitted.

[0069] A two-layer bag 71 according to a first comparative example manufactured in this manner is shown in FIGS. 19 to 22. FIG. 19 is a schematic perspective view of a two-layer bag 71 according to a first comparative example, compared to the two-layer bag 1 shown in FIG. 1, with the opening 2a moderately opened, and corresponds to FIG. 1. FIG. 20 is a schematic perspective view of the two-layer bag 71 shown in FIG. 19 with the opening 2a fully opened, and corresponds to FIG. 2. FIG. 21 is a schematic cross-sectional view taken along line E-E' in FIG. 19 and corresponds to FIG. 6. FIG. 22 is a schematic enlarged cross-sectional view of portion F in FIG. 21 and corresponds to FIG. 7. In FIGS. 19 to 22, elements that are the same as or correspond to those in FIGS. 1 to 7 are designated by the same reference numerals, and redundant explanations will be omitted.

[0070] In this first comparative example, the adhesive 22 is attached to the body 2 at a position near the edge of the opening 2a in a region R2 where a portion is missing rather than going around the body 2, so that the contents can accidentally enter between the outer layer 1A and the inner layer 1B through the missing portion of region R2.

[0071] 16, it is not possible to avoid the above-mentioned inconvenience by bonding the body 2 with adhesive 22 in the circumferential region R2 that continuously circumferentially surrounds the body 2 at a position close to the edge of the opening 2a, as in the two-layer bag 1 of this embodiment. This is presumably the reason why, as far as the inventors know, there have been no two-layer bags in which strip-shaped regions extending in the lengthwise direction of the inner tubular part are heat-sealed together, and the partial region includes the circumferential region.

[0072] In contrast, as described above, the manufacturing apparatus 31 shown in Figure 10 ensures that the adhesive 22 applied to the region R1 of the outer layer sheet 1A' by the applicator roller 49 does not transfer to the intended facing region R53 of the inner layer sheet 1B' on the top surface of the cylindrically folded inner layer sheet 1B' (including the intended facing region R53) until the inner layer sheet 1B' has passed the point facing the heater bar 53. Therefore, even though the band-shaped regions 1Ba, 1Bc extending along the length of the inner tubular portion formed by the inner layer 1B are heat-sealed to each other, the manufacturing apparatus 31 shown in Figure 10 can produce the two-layer bag 1 of this embodiment, in which the inner layer 1B is bonded with the adhesive 22 in the surrounding region R2 that continuously surrounds the body portion 2 near the edge of the opening 2a, without the above-mentioned inconvenience. Incidentally, in Figure 11, the top surface of the cylindrically folded inner layer sheet 1B' does not have an adhesive-transferable region R2' to which the adhesive 22 applied to the region R2 could transfer.

[0073] In the two-layer bag 1 of this embodiment, although the band-shaped regions 1Ba, 1Bc extending in the longitudinal direction of the inner tubular portion made of the inner layer 1B are heat-sealed to each other, they are bonded with adhesive 22 in the circumferential region R2 that continuously circumferentially surrounds the body portion 2 at a position close to the edge of the opening 2a. Therefore, compared to the two-layer bag 71 of the first comparative example, the risk of contents accidentally getting between the inner layer and the outer layer is reduced.

[0074] [Second embodiment]

[0075] FIG. 23 is a schematic perspective view of a two-layer bag 81 according to a second embodiment of the present invention, showing the opening 2a in a moderately opened state, corresponding to FIG. 1. FIG. 24 is a schematic perspective view of the two-layer bag 81 shown in FIG. 23, showing the opening 2a in a fully opened state, corresponding to FIG. 2. FIG. 25(a) is a schematic front view of the two-layer bag 81 shown in FIG. 23 in a flattened state, corresponding to FIG. 3(a). FIG. 25(b) is a schematic right side view of the two-layer bag 81 shown in FIG. 23 in a flattened state, corresponding to FIG. 3(b). FIG. 26 is a schematic cross-sectional view taken along line G-G' in FIG. 23, corresponding to FIG. 4. FIG. 27 is a schematic cross-sectional view taken along line H-H' in FIG. 23, corresponding to FIG. 6. FIG. 28 is a schematic cross-sectional view taken along line I-I' in FIG. 23. FIG. 29 is a schematic development view of the outer layer 1A of the two-layer bag 81 shown in FIG. 23, corresponding to FIG. 8. Figure 30 is a schematic development showing the inner layer 1B of the two-layer bag 81 shown in Figure 23, and corresponds to Figure 9. In Figures 23 to 30, elements that are the same as or correspond to elements in Figures 1 to 9 are given the same reference numerals, and redundant explanations will be omitted.

[0076] The two-layer bag 81 according to this embodiment differs from the first two-layer bag 1 in the following points.

[0077] Like the two-layer bag 1 according to the first embodiment, the two-layer bag 81 according to the present embodiment has an inner layer 1B forming an inner bag and an outer layer 1A forming an outer bag, with the inner layer 1B and the outer layer 1A being bonded only in a partial region. Similarly to the first embodiment, the body 2 according to the present embodiment has a double structure consisting of an inner tubular portion formed by the inner layer 1B and an outer tubular portion formed by the outer layer 1A. In this embodiment, as shown in Figures 23, 24, 28, 29, and 30, the inner tubular portion formed by the inner layer 1B has cuts 95b, 96b, 97b, and 98b extending from the edge of the tubular portion corresponding to the edge of the opening 2a toward the bottom 3. The outer tubular portion formed by the outer layer 1A has cuts 91b, 92b, 93b, and 94b extending from the edge of the tubular portion corresponding to the edge of the opening 2a toward the bottom 3.

[0078] 23, 24, and 26 to 30, in the body 2, the inner tubular portion made of the inner layer 1B and the outer tubular portion made of the outer layer 1A are bonded with adhesive 22 in a circumferential region R2 that continuously circumferentially surrounds the body 2, and only in a region R82 that is positioned closer to the edge of the opening 2a than the tips of any of the incisions 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b, and no bonding is provided between the inner layer 1B and the outer layer 1A at other locations on the body 2. Thus, in the present embodiment, the partial regions include the circumferential region R2 and the region R82.

[0079] In this embodiment, the circumferential region R2 is located relatively close to the edge of the opening 2a and continuously circumferentially around the body 2 at a position farther from the edge of the opening 2a toward the bottom 3 than any of the cuts 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b. The region R82 is located between the edge of the opening 2a and the circumferential region R2, and intermittently circumferentially around the body 2 so as to avoid any of the cuts 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b. In this embodiment, the circumferential region R2 and region R82 are regions on the opening 2a side that are bonded with adhesive, and are positioned so that when the edge of the opening 2a is virtually moved toward the bottom 3, the entire edge of the opening 2a comes into contact with somewhere in the region on the opening 2a side, and a part of the region is positioned closer to the edge of the opening 2a than the tip of any of the notches 91b, 92b, 93b, 94b, 95b, 96b, 97b, 98b.

[0080] In the two-layer bag 1 according to the first embodiment, the strip-shaped regions 1Ba, 1Bc extending in the longitudinal direction of the inner tubular portion of the inner layer 1B are heat-sealed to each other, whereas in the two-layer bag 81 according to this embodiment, instead, as shown in Figures 26 to 28 and 30, adhesive 99 is applied to a strip-shaped region R99 on the far side of the paper in Figure 30, which extends along the upper edge of the inner layer 1B in Figure 30 near the upper edge, and the adhesive 99 bonds the strip-shaped region R99 to a strip-shaped region 1Bd on the near side of the paper in Figure 30, which extends along the lower edge of the inner layer 1B in Figure 30.

[0081] In this embodiment, since heat sealing is not performed, neither the outer layer 1A nor both sides of the inner layer 1B need have heat sealing properties, and for example, both the outer layer 1A and the inner layer 1B may be made of kraft paper alone. However, in this embodiment, the same materials as those in the first embodiment may be used for the outer layer 1A and the inner layer 1B.

[0082] In this embodiment, the outer layer 1A has cuts 91a, 92a, 93a, and 94a extending from the right side to the left side in Fig. 29 on the extension lines of the cuts 91b, 92b, 93b, and 94b, respectively. The inner layer 1B has cuts 95a, 96a, 97a, and 98a extending from the right side to the left side in Fig. 30 on the extension lines of the cuts 95b, 96b, 97b, and 98b, respectively. In this embodiment, as can be seen from Figs. 34 to 37 described later, the square bottom 3 can be formed using the cuts 91a, 92a, 93a, 94a, 95a, 96a, 97a, and 98a.

[0083] Figure 31(a) is a schematic side view showing an example of a two-layer bag manufacturing apparatus (bag making machine) 101 used to manufacture the two-layer bag 81 shown in Figure 23, and corresponds to Figures 10(a) and 16(a). Figure 31(b) is a schematic plan view showing some elements 52, 114 of the manufacturing apparatus 101, and the outer layer sheet 1A' and inner layer sheet 1B', and corresponds to Figures 10(b) and 16(b). In Figure 31, elements that are the same as or correspond to elements in Figures 10 and 16 are designated by the same reference numerals, and redundant explanations will be omitted.

[0084] The manufacturing apparatus 101 differs from the manufacturing apparatus 61 shown in FIG. 16 in the following points.

[0085] The manufacturing apparatus 101 includes a sheet supply section 102 similar to the sheet supply section 32 in Figures 10 and 16, a slit forming / coating section 103, a cylindrical forming section 104, a cutting / bottom forming section 105, and an accumulation section 106.

[0086] As shown in FIG. 10, the incision forming / applying section 103 includes guide rollers 41, 42, 44, 45, 46, 111, 117, and 118, a rotor 112 with cutting blades that forms incisions 95a, 96a, 97a, 98a, 95b, 96b, 97b, and 98b in the inner layer sheet 1B' as shown in FIG. 33, a receiving roller 113 that receives the rotor 112 with cutting blades, an application nozzle 114 that applies adhesive 99 to region R99 of the inner layer 1B in FIG. 30, and incisions 91a, 92a, 93a, 94a, and 91b in the outer layer sheet 1A' as shown in FIG. a rotor 115 with cutting blades that form the outer layer sheet 1A'b, 92b, 93b, and 94b; a receiving roller 116 that receives the rotor 115 with cutting blades; an application nozzle 52 that applies adhesive 21 to region R1 of the outer layer 1A in Figure 29; a container 47 that contains adhesive that will become adhesives 22, 82, and 23; a take-out roller 48 that takes out the adhesive from the container 47; and an application roller 49 made of rubber or the like that applies the adhesive taken out by the take-out roller 48 to regions R22, R82, and R23 of the outer layer sheet 1A' that passes between the take-out roller 48 and the receiving roller 50.

[0087] Fig. 32 is a schematic plan view showing a portion of outer layer sheet 1A' that forms the continuum of outer layer 1A in Fig. 31, illustrating the locations of incisions 91a, 92a, 93a, 94a, 91b, 92b, 93b, and 94b. Fig. 33 is a schematic plan view showing a portion of inner layer sheet 1B that forms the continuum of inner layer 1B in Fig. 31, illustrating the locations of incisions 95a, 96a, 97a, 98a, 95b, 96b, 97b, and 98b.

[0088] 31 , after the cutting blade rotor 112 forms incisions 95a, 96a, 97a, 98a, 95b, 96b, 97b, and 98b in the inner layer sheet 1B′, the application nozzle 114 applies adhesive 99 to the region R99 in the inner layer sheet 1B′, and the inner layer sheet 1B′ is then guided to the guide roller 45. After the cutting blade rotor 115 forms incisions 91a, 92a, 93a, 94a, 91b, 92b, 93b, and 94b in the outer layer sheet 1A′, the application nozzle 52 applies adhesive 24 to the region R1, and the application roller 49 applies adhesives 22, 82, and 23 to the regions R2, R82, and R3 in the outer layer sheet 1A′, and the outer layer sheet 1A′ is then guided to the guide roller 45. The inner layer sheet 1B' and the outer layer sheet 1A' guided by the guide rollers 45 are overlapped again by the guide rollers 45, and then exit the incision forming / applying section 103 and enter the cylindrical forming section 104.

[0089] The cylindrical molding unit 104 molds the inner layer sheet 1B' and the outer layer sheet 1A' into a cylindrical shape and folds them to complete the bonding of each part with adhesives 21, 22, 23, 82, and 99. The cylindrical molding unit 104 has molding members that perform the molding, but these are not shown in the figure.

[0090] After the outer layer sheet 1A' and the inner layer sheet 1B' are formed into a complete cylindrical body by the cylindrical forming unit 104, this cylindrical body passes through guide rollers 54 and is cut into cylindrical bodies 81' for one two-layer bag 1 by the cutting and bottom forming unit 105. Each cylindrical body 81' for one two-layer bag 1 is folded by the cutting and bottom forming unit 105 using the incisions 91a, 92a, 93a, 94a, 95a, 96a, 97a, and 98a as shown in Fig. 34, and then adhesive is applied to region 121 as shown in Fig. 35. The bag is further folded as shown in Fig. 36, and a bottom sheet 3a such as paper is attached as shown in Fig. 36. In this way, the two-layer bag 81 shown in Fig. 23 is completed, and the completed two-layer bags 81 are accumulated in the accumulation unit 106.

[0091] Note that Figure 34 is a schematic back view showing the process of forming the bottom part 3 of the two-layer bag 81 shown in Figure 23. Figure 35 is a schematic back view showing the process of forming the bottom part 3 of the two-layer bag 91 shown in Figure 23 after the state shown in Figure 34. Figure 36 is a schematic back view showing the process of forming the bottom part 3 of the two-layer bag 81 shown in Figure 23 after the state shown in Figure 35. Figure 37 is a schematic back view showing the state after formation of the bottom part 3 of the two-layer bag 91 shown in Figure 23 has been completed.

[0092] In the two-layer bag 81 of this embodiment, similar to the two-layer bag 1 of the first embodiment, the desired contents are placed into the body portion 2 through the opening 2a at the top of the body portion 2, and then the opening 2a is closed to complete the bagged product.

[0093] In two-layer bag 81 according to the present embodiment, the inner tubular portion made of inner layer 1B and the outer tubular portion made of outer layer 1A are bonded together in circumferential region R2 with adhesive 22, so there is no risk of contents accidentally getting between inner layer 1B and outer layer 1A on the bottom 3 side. In two-layer bag 81 according to the present embodiment, the inner tubular portion made of inner layer 1B and the outer tubular portion made of outer layer 1A are bonded together in region R82 with adhesive 82, further reducing the risk of contents accidentally getting between inner layer 1B and outer layer 1A.

[0094] Figure 38 is a schematic perspective view showing a state in which the opening of a two-layer bag 131 according to a second comparative example, which is compared with the two-layer bag 81 shown in Figure 23, is moderately opened, and corresponds to Figure 1. In Figure 38, elements that are the same as or correspond to elements in Figure 23 are given the same reference numerals, and redundant explanations will be omitted.

[0095] The two-layer bag 131 shown in Figure 38 differs from the two-layer bag 81 shown in Figure 23 only in that, in the two-layer bag 81 shown in Figure 23, the inner tubular portion made of the inner layer 1B and the outer tubular portion made of the outer layer 1A are bonded together with adhesive 82 in region R82, whereas in the two-layer bag 131 shown in Figure 38, bonding is not performed in region R82.

[0096] In the two-layer bag 131 shown in Fig. 38, the region on the side of the opening 2a that bonds the inner tubular portion made of the inner layer 1B and the outer tubular portion made of the outer layer 1A is composed only of the circumferential region R2, and since the circumferential region R2 is positioned farther from the edge of the opening 2a toward the bottom 3 than any of the incisions 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b, there is a limit to how close the circumferential region R2 can be to the edge of the opening 2a. Therefore, if the region on the side of the opening 2a that bonds the inner tubular portion made of the inner layer 1B and the outer tubular portion made of the outer layer 1A is composed only of the circumferential region R2, as in the two-layer bag 131 shown in Fig. 38, there is a high risk that contents will accidentally get between the inner layer 1B and the outer layer 1A between the circumferential region R2 and the edge of the opening 2a. However, in two-layer bag 81 according to this embodiment, region R82 bonded with adhesive 82 is positioned closer to the edge of opening 2a than any of the tips of incisions 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b, reducing the risk of contents accidentally getting between inner layer 1B and outer layer 1A compared to two-layer bag 81 shown in Figure 38. Moreover, in two-layer bag 81 according to this embodiment, not only circumferential region R2 but also region R82 avoids incisions 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b, so even if incisions 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b are formed after adhesive 82 is applied, it is possible to form incisions 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b. There is no risk of the adhesive 22, 82 sticking to the blades of the cutting edges 112, 115 and causing problems, and even if the adhesive 22, 82 is applied after the cuts 91b, 92b, 93b, 94b, 95b, 96b, 97b, 98b are formed, there is no risk of the adhesive 22, 82 leaking from the cuts 91b, 92b, 93b, 94b, 95b, 96b, 97b, 98b to the back side of the applied surface and causing problems.

[0097] In the present invention, in the two-layer bag 81 according to this embodiment, the region R82 disposed between the circumferential region R2 and the edge of the opening 2a may be limited to a part of the region. For example, the region R82 does not have to be disposed on both side portions 13, 14.

[0098] In addition, in the present invention, examples of patterns of the region on the opening 2a side, which can be employed in a two-layer bag such as this embodiment, where an inner tubular portion made of inner layer 1B and an outer tubular portion made of outer layer 1A are bonded with an adhesive, are shown in Figure 39. Figure 39 is a partially enlarged schematic front view showing examples of patterns of the region on the opening 2a side, and shows the portion of front surface 11 on the opening 2a side.

[0099] FIG. 39(a) shows the pattern of the region on the opening 2a side in this embodiment.

[0100] FIG. 39(b) shows an example in which the region R82 bonded with the adhesive 82 is configured as shown by the broken line.

[0101] FIG. 39(c) shows an example in which the region R182 bonded with adhesive 182 is configured to have the same thickness so as to be as close as possible to the edge of opening 2a while avoiding cuts 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b.

[0102] FIG. 39(d) shows an example in which the region R222 bonded with adhesive 222 is configured with different thicknesses so as to be as close as possible to the edge of opening 2a while avoiding cuts 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b.

[0103] Figure 39(d) shows an example in which the area R322 bonded with adhesive 322 is configured to close the gap in the area R82 bonded with adhesive 82 at a position below the area R322 with sufficient horizontal margin.

[0104] In all of the examples shown in Figure 39, the area on the opening 2a side where the inner tubular portion made of inner layer 1B and the outer tubular portion made of outer layer 1A are bonded with adhesive is positioned so as to avoid any of the incisions 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b, and the opening side area is positioned so that when the edge of opening 2a is virtually moved toward bottom 3, the entire edge of opening 2a comes into contact with somewhere in the opening side area, and a part of the opening side area is positioned closer to the edge of opening 2a than the tip of any of the incisions 91b, 92b, 93b, 94b, 95b, 96b, 97b, and 98b.

[0105] Even when such an opening side region is employed, the same advantages as those of the two-layer bag 81 according to this embodiment can be obtained.

[0106] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. [Explanation of symbols]

[0107] 1,81 2-layer bag 1A outer layer 1A' outer layer sheet 1B inner layer 1B' Inner layer sheet 2. Torso 2a opening 22,82 Adhesive 25 Heat seal area 91b, 92b, 93b, 94b, 95b, 96b, 97b, 98b notches

Claims

1. A two-layer bag having an inner layer forming an inner bag and an outer layer forming an outer bag, the inner layer and the outer layer being bonded only in a partial region, a cylindrical body portion having an opening at one end and a closed other end, the body portion having a double structure consisting of an inner cylindrical portion made of the inner layer and an outer cylindrical portion made of the outer layer, band-like regions extending in the length direction of the inner tubular portion are heat-sealed to each other so that the inner layer forms the inner tubular portion; an outer surface region of the inner cylindrical portion that continuously surrounds the inner cylindrical portion at a position close to the edge of the opening and an inner surface region of the outer cylindrical portion that continuously surrounds the outer cylindrical portion at a position close to the edge of the opening are bonded together with an adhesive so as to face each other over the entire circumference of these regions; A two-layer bag characterized by:

2. one surface of the inner layer has heat sealability; the other surface of the inner layer is non-heat-sealable, a band-shaped portion along one side of the inner layer extending in the length direction of the inner tubular portion is folded back so that the surface on the one side faces outward, and the folded state is maintained by adhesion with an adhesive, The band-shaped portion is heat-sealed to a band-shaped region along another edge of the inner layer extending in the length direction of the inner tubular portion.

2. The two-layer bag according to claim 1.

3. 3. The two-layer bag according to claim 1, further comprising a square bottom portion that closes the other end of the body portion.

4. 4. A bagged product comprising the two-layer bag according to claim 1, a desired content being contained inside the inner bag, and the opening being closed.

5. A method for producing the two-layer bag according to any one of claims 1 to 3, comprising the steps of: applying the adhesive to a first sheet that forms a contiguous portion of the outer layer; the first and second sheets are guided so that the adhesive applied to the first sheet does not transfer to the intended facing region of the second sheet forming the continuous inner layer, which will face the heater bar that performs the heat sealing, until the intended facing region has passed the point facing the heater bar. A method for manufacturing a two-layer bag.

6. A manufacturing apparatus used to manufacture the two-layer bag according to any one of claims 1 to 3, an application unit that applies the adhesive to a first sheet that forms a continuous outer layer; a guide section for guiding the first and second sheets so that the adhesive applied to the first sheet does not transfer to a planned facing region of the second sheet forming the continuous inner layer, which will face a heater bar that performs the heat sealing, until the planned facing region has passed a point facing the heater bar; A manufacturing apparatus for two-layer bags, comprising:

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