Pouch, pouch manufacturing method, and pouch manufacturing equipment

Abstract

The present invention provides a pouch, a method for manufacturing the pouch, and equipment for manufacturing the pouch that can suppress the occurrence of opening defects. [Solution] A pouch 100 is made of two resin sheets 110 and 120 laminated together, with the bottom edges 110a and 120a of the sheets 110 and 120, one side edge 110b and 120b, and the other side edge 110c and 120c joined together, wherein the stiffness Ra of the central region 100A between one side edge 110b and 120b and the stiffness Rb of one side edge region 100B between the central region 100A and one side edge 110b and 120b, and the stiffness Rc of the other side edge region 100C between the central region 100A and the other side edge 110c and 120c are lower than the stiffness Ra of the central region 100A between one side edge 110b and 120b and the other side edge 110c and 120c.

Description

Technical Field

[0001] The present invention relates to a pouch in a bag shape for enclosing a fluid substance, a pouch manufacturing method, and pouch manufacturing equipment.

Background Art

[0002] Pouches for enclosing fluid substances such as beverages and fluid foods are required to have heat resistance, gas barrier properties, etc. so that they can be subjected to retort sterilization treatment after being enclosed. For such a pouch, for example, a sheet having a barrier layer formed by depositing an inorganic oxide such as silica or alumina on a base material of a polyethylene terephthalate (PET) resin film is used. This sheet is provided with a sealant layer of an unstretched polypropylene (CPP) resin film on the base material side of the barrier layer and an outer layer of a biaxially stretched polypropylene (OPP) resin film on the film side (see, for example, Patent Document 1 below).

[0003] In a pouch using such a sheet, first, two sheets are laminated, and the bottom sides, one side, and the other side of the sheets are heat-sealed and joined to each other to form a bag shape. Next, while moving both sides of this bag-shaped pouch closer to each other, the outer layer is sucked to separate the two sheets from each other, opening the top side, and a fluid substance is injected into the interior from the top side. Then, after heat-sealing the top side, it is subjected to retort sterilization treatment to obtain a pouch enclosing the fluid substance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0005] In recent years, for pouches like those mentioned above, there has been a demand for monomaterial construction using the same material, from the perspective of recyclability of the materials after use. Therefore, it is being considered to create pouches using all-PP sheets, where polypropylene (PP) resin is applied not only to the sealant layer and outer layer, but also to the barrier layer.

[0006] However, in pouches using all-PP sheets, if the heating process is not uniform between the two sheets during heat sealing, resulting in uneven heating, the pouch may warp due to differences in shrinkage between the sheets, given that the physical properties such as rigidity (stiffness) of each layer are similar. Such warping can easily lead to poor opening at the top, potentially making it difficult to reliably inject liquids.

[0007] Such problems can occur not only with pouches made from all-PP sheets, but also with pouches made from all-polyolefin resin sheets, including all-polyethylene (PE) resin sheets, as well as with pouches made from the same resin material, and even with pouches made from sheets where the materials of each layer are different but the physical properties such as the rigidity (stiffness) of each layer are similar.

[0008] Therefore, the present invention aims to provide a pouch, a method for manufacturing a pouch, and equipment for manufacturing a pouch that can suppress the occurrence of opening defects. [Means for solving the problem]

[0009] To solve the aforementioned problems, the pouch according to the present invention is a bag-shaped pouch in which two resin sheets are laminated and the bottom edge, one side edge, and the other side edge of the sheets are joined together, characterized in that the rigidity of one side edge region between the central region and the one side edge, and the rigidity of the other side edge region between the central region and the other side edge are lower than the rigidity of the central region between the one side edge and the other side edge of the sheet.

[0010] Furthermore, in the pouch according to the present invention, it is preferable that the sheet comprises a barrier layer containing a polyolefin resin and having gas barrier properties, and a sealant layer containing a polyolefin resin and having heat seal properties, and that the sheet contains 80% by mass or more of the polyolefin resin.

[0011] Furthermore, in the pouch according to the present invention, it is preferable that the ratio of the rigidity of one side region and the other side region to the rigidity of the central region is 75% or more and 98% or less.

[0012] Furthermore, in the pouch according to the present invention, it is preferable that the ratio of the length of one side region to the length of the other side region of the sheet to the length between the one side region and the other side region of the sheet is 25% or more and 75% or less.

[0013] On the other hand, a pouch manufacturing method according to the present invention for solving the aforementioned problems is a pouch manufacturing method described above, characterized by comprising: a sheet lamination step of laminating two sheets; a bag processing step of joining the bottom edge, one side edge, and the other side edge of the laminated sheets to form a bag shape; and a heat treatment step of heating only the one side edge region and the other side edge region of the sheet.

[0014] Furthermore, in the pouch manufacturing method according to the present invention, it is preferable that the heat treatment step is performed before the sheet lamination step in the pouch manufacturing method described above.

[0015] Furthermore, in the pouch manufacturing method according to the present invention, it is preferable that the heat treatment step is a step of heating only one side region and the other side region of the sheet at 80°C to 140°C.

[0016] Furthermore, the pouch manufacturing equipment according to the present invention, which solves the aforementioned problems, is a pouch manufacturing equipment described above, characterized by comprising: sheet lamination means for laminating two sheets; bag processing means for joining the bottom edge, one side edge, and the other side edge of the laminated sheets to process them into a bag shape; and heat treatment means for heating only the one side edge region and the other side edge region of the sheet.

[0017] Furthermore, the pouch manufacturing equipment according to the present invention preferably comprises, in the above-described pouch manufacturing equipment, a sheet feeding means for unwinding the strip-shaped sheet wound on a reel, and a sheet dividing means for cutting and dividing the strip-shaped sheet unwinded from the sheet feeding means along the unwinding direction, wherein the heat treatment means heats the strip-shaped sheets divided by the sheet dividing means before they are laminated by the sheet lamination means. [Effects of the Invention]

[0018] According to the pouch of the present invention, since the rigidity of the side region is lower than that of the central region, warping can be greatly suppressed, and even if it is made of a single material, it can exhibit high opening properties and greatly suppress the occurrence of opening defects.

[0019] Furthermore, the pouch manufacturing method and pouch manufacturing equipment according to the present invention make it easy to reliably manufacture the pouch according to the present invention. [Brief explanation of the drawing]

[0020] [Figure 1] This is a front view showing the schematic configuration of the main embodiment of the pouch according to the present invention. [Figure 2]It is a cross-sectional view showing a schematic configuration of the pouch of FIG. 1. [Figure 3] It is a schematic configuration diagram of a main embodiment of a pouch manufacturing facility according to the present invention. [Figure 4A] It is an explanatory view from the front when opening the pouch of FIG. 1. [Figure 4B] It is an explanatory view from the side when opening the pouch of FIG. 1. [Figure 4C] It is an explanatory view from the top when opening the pouch of FIG. 1. [Figure 5] It is a front view showing a schematic configuration when joining the top edges of the pouch of FIG. , [Embodiments for Carrying Out the Invention]

[0021] Embodiments of a pouch, a pouch manufacturing method, and a pouch manufacturing facility according to the present invention will be described based on the drawings. Note that the present invention is not limited only to the following embodiments described based on the drawings, and various technical matters described in each embodiment can be appropriately combined or replaced as necessary.

[0022] [Main Embodiments] Main embodiments of a pouch, a pouch manufacturing method, and a pouch manufacturing facility according to the present invention will be described based on FIGS. 1 to 5.

[0023] 〈Pouch〉 As shown in FIGS. 1 and 2, the pouch 100 according to the present embodiment is formed by laminating two resin sheets 110 and 120, and the bottom edges 110a and 120a, one side edge 110b and 120b, and the other side edge 110c and 120c of the sheets 110 and 120 are joined respectively, and the top edges 110d and 120d are open without being joined, forming a bag shape.

[0024] As shown in Figure 2, sheets 110 and 120 comprise a barrier layer 111 and 121 containing polypropylene (PP) resin and having gas barrier properties, a sealant layer 112 and 122 containing PP resin and having heat seal properties, and an outer layer 113 and 123 containing PP resin and protecting the outer surface.

[0025] The barrier layers 111 and 121 are formed by depositing inorganic oxides such as silica and alumina onto a substrate (approximately 20 to 80 μm thick) made of PP resin to create a coating (approximately 30 to 50 nm thick), which enables them to exhibit excellent gas barrier properties against oxygen, water vapor, and the like.

[0026] The sealant layers 112 and 122 are provided on the inner side of the barrier layers 111 and 121 and consist of a PP resin film (thickness approximately 20 to 80 μm). They are made of unoriented PP (CPP) resin to achieve high heat sealability. The outer layers 113 and 123 are provided on the outer side of the barrier layers 111 and 121 and consist of a PP resin film (thickness approximately 15 to 30 μm). They are made of biaxially oriented PP (OPP) resin to achieve high strength.

[0027] The PP resin used in each of these layers 111, 121, 112, 122, 113, and 123 can be made from virgin resin or recycled resin. Sheets 110 and 120 made from such PP resin are so-called monomaterials containing 80% or more by mass of PP resin.

[0028] Then, the sealant layers 112 and 122 of sheets 110 and 120 are stacked facing each other, and the bottom edges 110a and 120a, one side edge 110b and 120b, and the other side edge 110c and 120c are heated and joined (heat sealed) to form a bottom joint 100a, one side joint 100b, and the other side joint 100c, thereby creating a bag-shaped pouch 100.

[0029] As shown in Figure 1, in this pouch 100, the area between one side 110b,120b and the other side 110c,120c of the sheet 110,120 forms a central region 100A. Furthermore, the area between the central region 100A and one side 110b,120b forms one side region 100B. In addition, the area between the central region 100A and the other side 110c,120c forms the other side region 100C.

[0030] Furthermore, in the pouch 100 described above, the stiffness (rigidity) Ra of the central region 100A is lower than the stiffness (rigidity) Rb of one side region 100B and the stiffness (rigidity) Rc of the other side region 100C (Ra>Rb, Ra>Rc).

[0031] Specifically, it is preferable that the pouch 100 has a ratio Rba (=Rb / Ra) of the stiffness (rigidity) Rb of one side region 100B and Rca (=Rc / Ra) of the stiffness (rigidity) Rc of the other side region 100C to the stiffness (rigidity) Ra of the central region 100A, which is between 75% and 98% (75% ≤ (Rba, Rca) ≤ 98%).

[0032] In particular, a ratio of 75% to 87% (75% ≤ (Rba, Rca) ≤ 87%) is more preferable. This is because when the above ratios of Rba and Rca are within the above range, the occurrence of opening defects can be reliably suppressed.

[0033] Furthermore, it is preferable that the stiffness (rigidity) Rb of one side region 100B and the stiffness (rigidity) Rc of the other side region 100C be the same value (Rb=Rc) rather than different values ​​(Rb≠Rc). In other words, it is preferable that the above ratio Rba and the above ratio Rca be the same value (Rba=Rca) rather than different values ​​(Rba≠Rca). This is because it is easier to open the holes in a balanced manner when using a filling machine.

[0034] Furthermore, it is preferable that the pouch 100 has a ratio W (=(W2+W3) / W0) of the length W0 between one side region 100B and the other side region 100C, where W2 and W3 occupy the length W0 between one side 110b,120b and the other side 110c,120, which is 25% or more and 75% or less (25%≦W≦75%).

[0035] In particular, a ratio of 30% to 70% (30% ≤ W ≤ 70%) is more preferable, and a ratio of 40% to 60% (40% ≤ W ≤ 60%) is even more preferable. This is because when the above ratio W is within the above range, the occurrence of opening defects can be reliably suppressed.

[0036] <Pouch manufacturing equipment> The configuration of the pouch manufacturing equipment according to this embodiment for manufacturing such a pouch 100 will be explained with reference to Figure 3.

[0037] As shown in Figure 3, the pouch manufacturing equipment F100 according to this embodiment includes a sheet feeding device F110 which is a sheet feeding means, a sheet dividing device F120 which is a sheet dividing means, a heat treatment device F130 which is a heat treatment means, a sheet stacking device F140 which is a sheet stacking means, a bag processing device F150 which is a bag processing means, and a sheet cutting device F160 which is a sheet cutting means.

[0038] The sheet feeding device F110 includes a feeding device F111 that feeds out a strip-shaped sheet S wound on a reel, and a guide roller F112 that guides and feeds the fed-out strip-shaped sheet S to the sheet splitting device F120. The sheet splitting device F120 includes a slitter F121 that cuts the strip-shaped sheet S from the sheet feeding device F110 along the feeding direction, thereby splitting it into a strip-shaped sheet S1 that will be the material for sheet 110 and a strip-shaped sheet S2 that will be the material for sheet 120.

[0039] Furthermore, the sheet splitting device F120 includes a guide roller F122 that separates and guides the cut strip-shaped sheets S1 and S2 so that they flow along different paths, as well as a reversal guide roller (not shown) which is a reversal means that guides and feeds one of the cut strip-shaped sheets S1, S2 to the heat treatment device F130 while reversing the orientation of the front and back surfaces of one of the sheets S1.

[0040] The heating apparatus F130 is equipped with heaters F131 and F132 that heat only the parts of sheet 110 and 120 corresponding to one side region 100B and the other side region 100C of the pouch 100, respectively, of the strip-shaped sheets S1 and S2 that have been divided by the sheet dividing apparatus F120.

[0041] Furthermore, the heating apparatus F130 includes guide rollers F133 and F134 that guide and feed strip-shaped sheets S1 and S2 from the sheet splitting apparatus F120 to heaters F131 and F132, and guide rollers F135 and F136 that guide and feed strip-shaped sheets S1 and S2 from heaters F131 and F132 to the sheet stacking apparatus F140.

[0042] The sheet lamination device F140 is equipped with a pinch roller F141 that stacks the sealant layers 112 and 122 of the strip-shaped sheets S1 and S2, which have been heat-treated in the heat treatment device F130, so that they face each other, and then guides and feeds them to the bag processing device F150.

[0043] The bag processing device F150 includes a bottom seal forming device F151 that heats the portions corresponding to the bottom edges 110a and 120a of sheets 110 and 120 to form a bottom joint portion 100a on strip-shaped sheets S1 and S2 stacked by the sheet lamination device F140, and a bottom seal cooling device F152 that cools and fixes the bottom joint portion 100a.

[0044] Furthermore, the bag processing device F150 includes a side seal forming device F153 that heats the parts corresponding to one side edge 110b, 120b and the other side edge 110c, 120c of the strip-shaped sheets S1, S2 to form one side joint 100b and the other side joint 100c, and a side seal cooling device F154 that cools and fixes one side joint 100b and the other side joint 100c.

[0045] Furthermore, the bag processing device F150 includes a pinch roller F155 that guides and feeds strip-shaped sheets S1 and S2 from the bottom seal cooling device F152 to the side seal forming device F153, and a pinch roller F156 that guides and feeds strip-shaped sheets S1 and S2 from the side seal cooling device F154 to the sheet cutting device F160.

[0046] The sheet cutting device F160 includes a cutting machine F161 that cuts strip-shaped sheets S1 and S2 from the bag processing device F150 along a direction perpendicular to the feeding direction to isolate bag-shaped pouches 100, and a conveying device (not shown) that transports the isolated pouches 100 to a subsequent process.

[0047] <Pouch manufacturing method> The pouch manufacturing method according to this embodiment, which utilizes such pouch manufacturing equipment F100, will now be described.

[0048] A strip-shaped sheet S is fed from the feeder F111 of the sheet feeding device F110 and guided and fed to the sheet splitting device F120 by guide rollers F112 (sheet feeding process). The sheet S is cut along the feeding direction by a slitter F121 and divided into strip-shaped sheets S1 and S2, which are then separated into different paths by guide rollers F122 (sheet splitting process) and guided and fed to the heat treatment device F130. At this time, the orientation of the front and back surfaces of sheet S1 is reversed by the reversing guide roller.

[0049] Sheets S1 and S2 are fed to heaters F131 and F132 via guide rollers F133 and F134, and only the parts of sheet 110 and 120 corresponding to one side region 100B and the other side region 100C of pouch 100 are heat-treated to a temperature of 80°C to 140°C (heat treatment process).

[0050] The heat-treated sheets S1 and S2 are guided and fed to the sheet stacking device F140 via guide rollers F135 and F136, where they are stacked by pinch roller F141 so that the sealant layers 112 and 122 face each other (sheet stacking process), and then guided and fed to the bag processing device F150.

[0051] The stacked sheets S1 and S2 are heated (160°C to 180°C) at the bottom edges 110a and 120a of sheets 110 and 120 by the bottom seal forming device F151 to form a bottom joint 100a, and then cooled and fixed by the bottom seal cooling device F152.

[0052] Sheets S1 and S2 are then guided and fed by pinch rollers F155, and the side seal forming device F153 heats (160°C to 180°C) the parts corresponding to one side 110b, 120b and the other side 110c, 120c of sheets 110 and 120 to form one side joint 100b and the other side joint 100c. After that, the side seal cooling device F154 cools and fixes the sheets together.

[0053] As a result, sheets S1 and S2 are sequentially formed into bag shapes at specified intervals along the feeding direction (longitudinal direction) (bag processing process), and are guided and fed to the sheet cutting device F160 via the pinch roller F156.

[0054] Sheets S1 and S2 are cut by the cutting machine F161 at predetermined intervals along the feeding direction and along a direction perpendicular to the feeding direction (short side direction) to isolate them as bag-shaped pouches 100 (sheet cutting process), and are then transported to the next process by the conveying device.

[0055] <Effects> In the pouch 100 manufactured in this manner, even if the all-PP sheet 110 and the other sheet 120 cannot be heated uniformly during the bag manufacturing process, resulting in uneven heating and shrinkage differences between the sheets 110 and 120, the aforementioned heat treatment makes the rigidity (stiffness) Rb of one side region 100B and the rigidity (stiffness) Rc of the other side region 100C lower than the rigidity (stiffness) Ra of the central region 100A (Ra>Rb, Ra>Rc), thus significantly suppressing warping.

[0056] This section describes the process of filling such a pouch 100 with a liquid substance such as a beverage or liquid food using a filling machine. As shown in Figures 4A to 4C, one side joint 100b and the other side joint 100c of the pouch 100 are gripped by grippers 11A and 11B, respectively, while the central region 100A of the sheets 110 and 120 is adsorbed by suction pads 12A and 12B, respectively.

[0057] Then, the grippers 11A and 11B are moved so that one side joint 100b and the other side joint 100c of the pouch 100 are brought closer together, while the suction pads 12A and 12B are moved so that the sheets 110 and 120 are separated from each other. As a result, the pouch 100 is less likely to warp, so the tops 110d and 120d of the sheets 110 and 120 can be reliably pulled apart to open the pouch, and the fluid can be easily injected into the interior.

[0058] As shown in Figure 5, the pouch 100, which has been filled with the fluid inside, is heat-sealed on the top edges 110d and 120d of the sheets 110 and 120 to form a top joint 100d, and then subjected to retort sterilization to become a pouch P containing the fluid.

[0059] Therefore, according to the pouch 100 of this embodiment, even if it is made of a single material, it can exhibit high opening properties and significantly suppress the occurrence of opening defects. Furthermore, according to the pouch manufacturing method and pouch manufacturing equipment F100 of this embodiment, the above-mentioned pouch 100 can be reliably manufactured easily.

[0060] In addition, after separating sheet S into sheets S1 and S2, the portions of sheet S1 and S2 corresponding to the side regions 100B and 100C of sheet S100 are heat-treated before the sheets S1 and S2 are laminated. In other words, the heat treatment is performed before the sheets S1 and S2 are laminated. Therefore, it is possible to reliably prevent sheets S1 and S2 from joining together over the entire portions corresponding to the side regions 100B and 100C during the heat treatment.

[0061] Furthermore, the strip-shaped sheets S, wound on a reel, are unwound, cut, and divided into strip-shaped sheets S1 and S2. These strips are then stacked and processed into a bag shape, which is then cut to continuously produce pouches 100. As a result, pouches 100 can be manufactured in a single pass in line from the raw material sheet S, enabling efficient production.

[0062] [Other embodiments] In the embodiments described above, the present invention was described as a pouch 100 formed by joining all-PP sheets 110 and 120, where the barrier layers 111 and 121, sealant layers 112 and 122, and outer layers 113 and 123 are all made of PP. However, the present invention is not limited to this. As for other embodiments, the present invention can be applied in the same manner as in the embodiments described above, as well as pouches formed by joining sheets made of all-polyolefin resin, such as all-PE sheets, and pouches formed by joining resin materials of the same material, or any bag-shaped pouch formed by joining sheets where the materials of each layer are different but the physical properties such as the rigidity (stiffness) of each layer are similar.

[0063] Furthermore, while the above-described embodiment described a case in which a pouch 100 is formed by joining sheets 110, 120, each consisting of a barrier layer 111, 121, a sealant layer 112, 122, and an outer layer 113, 123, the present invention is not limited to this. In other embodiments, for example, it is also possible to form a pouch by joining sheets in which the outer layers 113, 123 are omitted. However, as in the above-described embodiment, a pouch 100 formed by joining sheets 110, 120, each containing the outer layers 113, 123, is highly preferable because it allows for increased strength.

[0064] Furthermore, while the above-described embodiment described a case where only the bottom edges 110a, 120a, one side edge 110b, 120b, the other side edge 110c, 120c, and the top edges 110d, 120d of sheets 110, 120 are joined together to form a pouch 100, the present invention is not limited to this. As another embodiment, for example, it is also applicable to a pouch further provided with a spout.

[0065] Furthermore, while the above-described embodiment described a pouch 100 in which the bottom edges 110a, 120a, one side edge 110b, 120b, and the other side edge 110c, 120c of sheets 110, 120 are directly joined, the present invention is not limited to this. As another embodiment, for example, it can also be applied to a gusseted pouch in which a gusset such as a bottom material is interposed between the bottom edges 110a, 120a of sheets 110, 120.

[0066] Furthermore, in the embodiments described above, sheets S1 and S2 were heat-treated separately before lamination, that is, sheets S1 and S2 were heat-treated individually before lamination. However, the present invention is not limited to this. In other embodiments, for example, depending on the heat treatment conditions, it is also possible to heat-treat sheets S1 and S2 together after lamination. However, as in the embodiments described above, heat-treating sheets S1 and S2 individually before lamination is highly preferable because it reliably prevents sheets S1 and S2 from joining together before bag processing.

[0067] Furthermore, in the embodiments described above, a strip-shaped sheet S wound on a reel is unwound, cut along the unwound direction to divide the strip-shaped sheets S1 and S2, which are then subjected to heat treatment, lamination, and bag processing before being cut along a direction perpendicular to the unwound direction to manufacture a pouch 100. However, the present invention is not limited to this. In other embodiments, for example, a sheet obtained by cutting the strip-shaped sheets S1 and S2, which are obtained by cutting a strip-shaped sheet S wound on a reel along the unwound direction, along a direction perpendicular to the strip-shaped sheets, is prepared in advance, and the pouch 100 is manufactured by subjecting this sheet to heat treatment, lamination, and bag processing.

[0068] However, as in the embodiment described above, if a strip-shaped sheet S wound on a reel is unwound, cut along the unwound direction to divide it into strip-shaped sheets S1 and S2, and then subjected to heat treatment, lamination, and bag processing, and then cut along a direction perpendicular to the unwound direction, then pouches 100 can be manufactured in a single pass in line from the strip-shaped sheet S, which allows for efficient production and is highly preferable. [Examples]

[0069] Examples of the pouch according to the present invention will be described in detail. However, the present invention is not limited to the following examples described in detail.

[0070] [Relationship between heat treatment temperature and rigidity] <Preparation of test specimens> A barrier layer (50 nm thick) was fabricated by depositing silica onto a substrate made of OPP resin film (20 μm thick). An outer layer was provided by bonding an OPP resin film (20 μm thick) to the coating side of this barrier layer using a urethane resin adhesive (approximately 2 μm thick). A sealant layer was also provided by bonding a CPP resin film (60 μm thick) to the substrate side of the barrier layer using a urethane resin adhesive (approximately 2 μm thick). This resulted in the creation of a sheet (approximately 100 μm thick) for use as a test specimen.

[0071] Next, the sheets were heated from the outer layer side using a sealing bar (sealant layer side: silicone rubber) for 1 second at the temperatures shown in Table 1 to produce test specimens A0 to A8. Test specimen A8 (heat treatment temperature 150°C) was unusable because the sheet underwent thermal shrinkage.

[0072] <Testing Method> The stiffness (rigidity) R was determined by measuring the loop stiffness of each sample, which was cut from test specimens A0 to A7 into strips (15 mm wide x 100 mm long). Loop stiffness is obtained by holding both ends of the sample in the longitudinal direction to form a loop shape, compressing the sample to a specified length to deform the loop shape, and measuring the rebound force (mN) from the sample at that time. The measurement conditions are shown below.

[0073] • Testing machine: Manufactured by Toyo Seiki Seisakusho Co., Ltd. "Loop Stephne Tester (Registered Trademark) 581 (Part Number)" ·Temperature: 23℃ ·Humidity: 55% • Loop length: 50mm • Compressed length: 10mm ·Compression speed: 3.3mm / sec

[0074] <Test Results> The test results are shown in Table 1 below.

[0075] [Table 1]

[0076] As can be seen from Table 1, heat treatment reduces the stiffness (resilience) R, and increasing the heat treatment temperature further reduces the stiffness (resilience) R.

[0077] [Evaluation of mouth opening ability] <Preparation of test specimens> As described above, sheets for the test specimens were prepared and cut to the specified size (width 116 mm x length 155 mm) (80 sheets). Next, only the side regions on both sides in the width direction of the sheets (within a range of 30 mm from the side) were heat-treated at the temperatures shown in Table 2 (1 second each) (10 sheets each), and two sheets were stacked so that the sealant layers of the sheets faced each other (5 sets each). Then, the bottom edges and side edges of the sheets were heated (180°C x 1 second) and heat-sealed (seal width 10 mm) to create bag-shaped pouch test specimens B0 to B7 (5 sheets each).

[0078] <Evaluation Method> Test specimens B0 to B7 were placed in a filling machine and the pouch opening process was performed (5 times) to confirm whether they could be opened as specified without any opening defects. The results are shown in Table 2 below. In Table 2, "×" indicates the result when no heat treatment was performed (B0), i.e., two opening defects occurred out of five attempts; "○" indicates that one opening defect occurred, but this was fewer than with no heat treatment (B0); and "◎" indicates that all specimens were opened as specified without any opening defects.

[0079] Furthermore, since the central region is not heat-treated, its stiffness Ra is the same as the stiffness R of test specimen A0. The stiffnesses Rb and Rc of the one and the other side regions are the same as the stiffness R of the corresponding heat-treated test specimens A1 to A7, depending on the heat treatment temperature. Based on these values, the ratios Rba and Rca are determined.

[0080] <Evaluation Results> The evaluation results are shown in Table 2 below.

[0081] [Table 2]

[0082] As can be seen from Table 2, the standard test specimen B0 (conventional), which was not subjected to heat treatment, resulted in two opening failures out of five trials. In contrast, test specimens B1 to B7 (75% ≤ (Rba, Rca) ≤ 98%), which were heat-treated at 80°C or higher, showed fewer opening failures than test specimen B0. In particular, test specimens B3 to B7 (75% ≤ (Rba, Rca) ≤ 87%), which were heat-treated at 100°C or higher, were able to open completely without any opening failures.

[0083] Based on the above, we were able to confirm the effectiveness of the pouch according to the present invention. [Industrial applicability]

[0084] The pouch, pouch manufacturing method, and pouch manufacturing equipment according to the present invention can be used very effectively in various industries, including the manufacturing of fluid products such as beverages and liquid foods. [Explanation of Symbols]

[0085] 11A, 11B Gripper 12A, 12B Suction Pads 100 pouches 100A central area 100B One side region 100C Tetralateral Region 100a Base joint 100b One side joint 100c Other side joint 100d Top joint 110,120 seats 110a, 120a base 110b, 120b One side 110c, 120c The other side 110d, 120d Top 111,121 Barrier layer 112,122 sealant layer 113,123 Outer layer F100 Pouch Manufacturing Equipment F110 Sheet Feeding Device F111 Feeding device F112 Guide Roller F120 Seat Splitter F121 Slitta F122 Guide Roller F130 Heat Treatment Apparatus F131, F132 Heater F133~F136 Guide Rollers F140 Sheet Lamination Machine F141 Pinch Roller F150 bag processing equipment F151 Bottom seal forming apparatus F152 Bottom Seal Cooling Unit F153 Side seal forming device F154 Side seal cooling device F155, F156 Pinch Roller F160 Sheet Cutting Machine F161 Cutting Machine S, S1, S2 strip-shaped sheets

Claims

1. A pouch in the shape of a bag, in which two resin sheets are laminated together, and the bottom edge, one side edge, and the other side edge of the sheets are joined together, The rigidity of the central region between the one side and the other side of the sheet is lower than the rigidity of the central region between the one side and the other side of the sheet. A pouch characterized by the following features.

2. The aforementioned sheet is A barrier layer containing polyolefin resin and having gas barrier properties, A sealant layer containing polyolefin resin and having heat-sealing properties, It is equipped with, It contains 80% by mass or more of the aforementioned polyolefin resin. The pouch according to feature 1.

3. The ratio of the rigidity of one side region and the other side region to the rigidity of the central region is 75% or more and 98% or less. The pouch according to feature 1.

4. The ratio of the length of one side region to the length of the other side region of the sheet, in the total length between the one side region and the other side region, is 25% or more and 75% or less. The pouch according to feature 1.

5. A method for manufacturing a pouch according to claim 1, A sheet lamination process in which two of the aforementioned sheets are stacked, A bag processing step in which the bottom edge, one side edge, and the other side edge of the stacked sheets are joined together to form a bag shape, A heat treatment step of heating only one side region and the other side region of the sheet, A method for manufacturing pouches, characterized by performing the following.

6. The heat treatment step is performed before the sheet lamination step. The pouch manufacturing method according to feature 5.

7. The heat treatment step is a step of heating only one side region and the other side region of the sheet to a temperature of 80°C or higher and 140°C or lower. The pouch manufacturing method according to feature 5.

8. A pouch manufacturing apparatus according to claim 1, A sheet lamination means for stacking two of the aforementioned sheets, A bag processing means for joining the bottom edge, one side edge, and the other side edge of the stacked sheets together to form a bag shape, A heating treatment means for heating only one side region and the other side region of the sheet, A pouch manufacturing facility characterized by having the following features.

9. A sheet feeding means for unwinding the sheet, which is in the shape of a strip wound on a reel, A sheet splitting means for cutting and dividing the strip-shaped sheet unfed from the sheet feeding means along the unfed direction, Equipped with, The heat treatment means heats each of the strip-shaped sheets that have been divided by the sheet dividing means before they are stacked by the sheet stacking means. The pouch manufacturing equipment according to feature 8.

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