Packaging bag and method for opening a packaging bag

Abstract

Provided is a packaging bag that is easy to manufacture and that can have a wide opening. According to the present invention, a packaging bag is provided that includes a tubular body formed by forming a longitudinal seal portion on a film, the longitudinal seal portion being formed by overlapping an inner face of one edge side of the film with an inner face of the other edge side of the film, and by fusing the film to each other at the overlapping portion, an upper lateral seal portion configured to close an upper side of the tubular body, a lower lateral seal portion configured to close a lower side of the tubular body, and a tear initiation portion provided at the overlapping portion, the packaging bag being formed of the overlapping portion and a main body portion other than the overlapping portion, a tear strength of the film in a longitudinal direction of the longitudinal seal portion, i.e., a first tear strength, being set to S1, and a tear strength of the film in a direction orthogonal to the longitudinal direction, i.e., a second tear strength, being set to S2, S2 / S1 being 1.5 to 10.

Description

[0001] This application is a divisional application of the original application filed on October 27, 2021, with application number 2021800719018 and invention title "Packaging Bag". Technical Field

[0002] This invention relates to packaging bags. Background Technology

[0003] (First viewpoint) Patent document 1 discloses a packaging bag in which a continuous straight opening seam is formed in the middle layer parallel to the back heat-sealed part, and a wider opening can be formed by opening along the opening seam.

[0004] (Second viewpoint) Patent document 2 discloses a method in which a laminated film having an adhesive layer is sterilized by contacting it with a bactericide composed of hydrogen peroxide, and then the laminated film is used to make bags for filling.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2008-254800 Patent Document 2: Japanese Patent Application Publication No. 2015-81142 Summary of the Invention The problem the invention aims to solve (First viewpoint) When manufacturing the packaging bag with the structure of Patent Document 1, it is necessary to form an opening gap on the film that constitutes the intermediate layer before laminating the film with other films, which is cumbersome to manufacture.

[0006] The present invention was made in view of the above circumstances, and provides a packaging bag that is easy to manufacture and can be formed with a wide opening.

[0007] (Second viewpoint) Existing bag-filling based packaging bags, such as those in Patent Document 2, have the disadvantage of being difficult to open.

[0008] The present invention was made in view of the above circumstances, and provides a packaging bag that can be easily opened.

[0009] means for solving problems (First viewpoint) According to the present invention, there is provided a packaging bag, which includes a cylindrical body formed by forming a longitudinal seal portion on a film, an upper transverse seal portion, a lower transverse seal portion, and a tear start portion. The longitudinal seal portion is formed by bending the film into a cylindrical shape and overlapping the inner surface of one edge side of the film with the inner surface of the other edge side, and the film is welded to each other at the overlapping portion. The upper transverse seal portion is provided to close the upper side of the cylindrical body. The lower transverse seal portion is provided to close the lower side of the cylindrical body. The tear start portion is provided at the overlapping portion. The packaging bag is composed of the overlapping portion and the main body portion other than the overlapping portion. When the tear strength in the longitudinal direction of the longitudinal seal portion of the film, that is, the first tear strength, is set as S1, and the tear strength in the orthogonal direction orthogonal to the longitudinal direction, that is, the second tear strength, is set as S2, S2 / S1 is 1.5 to 10.

[0010] The packaging bag configured as described above is formed of a film with S2 / S1 being 1.5 to 10. Therefore, if both hands grasp both sides of the tear start portion and the distance between the two hands is expanded in the longitudinal direction of the longitudinal seal portion, tearing starts at the tear start portion. After the tear reaches the main body portion, in the main body portion, the tear expands obliquely to both sides across the overlapping portion. In this state, the tear travels in the longitudinal direction of the longitudinal seal portion. Therefore, a relatively wide opening can be formed by tearing. In addition, there is no need to form an opening slit on the film constituting the intermediate layer as in Patent Document 1, so it is easy to manufacture.

[0011] Various embodiments of the present invention are exemplified below. The embodiments shown below can be combined with each other.

[0012] Preferably, S2 / S1 of the packaging bag is 2 to 6.

[0013] Preferably, in a state where the packaging bag is filled with contents, the roundness of the cross-section perpendicular to the longitudinal direction at the center in the longitudinal direction of the longitudinal seal portion is 0.5 or more.

[0014] (Second aspect) According to the present invention, there is provided a packaging bag, which is composed of films laminated in multiple layers. The packaging bag includes: a cylindrical body formed by forming a longitudinal seal portion on the film; an upper transverse seal portion; a lower transverse seal portion; and an opening portion. The upper transverse seal portion is provided to close the upper side of the cylindrical body. The lower transverse seal portion is provided to close the lower side of the cylindrical body. When the tensile elastic modulus of the film in the longitudinal direction along the longitudinal seal portion is set as Ve, and the tensile elastic modulus of the film in the transverse direction along the transverse seal portion is set as He, the relationship Ve < He is satisfied. The opening portion is formed along the transverse direction.

[0015] With this configuration, the longitudinal tensile modulus of elasticity is lower than the transverse tensile modulus of elasticity. When the film is opened with the opening portion of the transverse sealing portion, the longitudinal stretching of the film is suppressed, thus making opening easy.

[0016] Various embodiments of the present invention are illustrated below. The embodiments shown below can be combined with each other.

[0017] Preferably, the opening portion is formed on the upper horizontal sealing portion.

[0018] Preferably, the upper horizontal sealing portion has a perforated line as the opening portion.

[0019] Preferably, an unsealed portion is formed in the direction in which the opening portion extends within the upper transverse sealing portion.

[0020] Preferably, the upper limit of the tensile modulus He of the membrane in the transverse direction is 1000 MPa. Attached Figure Description

[0021] Figure 1 This is a plan view of the packaging bag 1 in its unfilled state (viewpoint 1).

[0022] Figure 2 This is a three-dimensional view of packaging bag 1 containing its contents.

[0023] Figure 3A This is a cross-sectional view of the longitudinal sealing portion 7 at the center of the longitudinal side D1, perpendicular to the longitudinal side D1, with the packaging bag 1 filled with contents. Figure 3B yes Figure 3A A magnified view of region B in the middle.

[0024] Figure 4A This is a three-dimensional diagram showing the lines through which membrane 2 is torn, starting from the tear initiation point 6. Figure 4B yes Figure 4A A magnified view of region B in the middle.

[0025] Figure 5 This is a structural diagram of the bag filling machine 101.

[0026] Figure 6 This is an enlarged view of the vicinity of the horizontal sealing machine 116 of the bag filling machine 101, showing the state in which the horizontal sealing part 11 is formed by the horizontal sealing machine 116.

[0027] Figure 7 Indicates from Figure 6 The process begins with opening the horizontal sealing machine 116, and the shutter component 123 returning to its initial position. After the horizontal sealing part 11 moves to the position of the pressure cutter 118, the pressure cutter 118 clamps the horizontal sealing part 11 and cuts it off. Then, the process continues with opening the pressure cutter 118 and the flattening roller 115.

[0028] Figure 8 Indicates from Figure 7 After the contents W are further added, the flattening roller 115 is closed, and then the sealing part 3a moves to the position of the opening and closing part 123.

[0029] Figure 9 Indicates from Figure 8 The state begins with the opening and closing component 123 clamping the sealing part 3a, and the state after that is when it moves downward in the vertical direction.

[0030] Figure 10 This is a plan view of packaging bag 1 in the (second viewpoint) implementation.

[0031] Figure 11 This is a plan view of packaging bag 1 as a variation.

[0032] Figure 12 This is an explanatory diagram used to illustrate blow molding.

[0033] Figure 13 This is an explanatory diagram used to illustrate the bag-making and filling method.

[0034] Figure 14 This is a diagram showing the tensile modulus Ve in the longitudinal direction and the tensile modulus He in the transverse direction of the packaging bag 1 in the embodiment. Detailed Implementation

[0035] The embodiments of the present invention will be described below. The various features shown in the embodiments described below can be combined with each other. Furthermore, each feature can independently constitute an invention. The items described in the first and second viewpoints can be combined with each other.

[0036] (First viewpoint) 1. Packaging bag 1 like Figures 1-4B According to one embodiment of the present invention, the packaging bag 1 includes a cylindrical body 3 formed by forming a longitudinal sealing portion 7 on a film 2, an upper transverse sealing portion 4, a lower transverse sealing portion 5, and a tear initiation portion 6. The packaging bag 1 is usually filled with contents, but... Figure 1 For clarity, packaging bag 1 is shown in its unfilled state. Examples of contents include viscous foods such as flower paste, jam, and fillings.

[0037] The following is Figure 1The directions up, down, left, and right are used to describe the packaging bag 1. Specifically, the axis of the cylinder 3 is the up-down direction. When the longitudinal sealing part 7 is positioned near the front, the left and right are the packaging bag 1. Furthermore, the side of the longitudinal sealing part 7 is considered the front, and the opposite side is considered the back. The up-down direction is the long side direction D1 of the longitudinal sealing part 7, and the left-right direction is the orthogonal direction D2 that is orthogonal to the long side direction D1.

[0038] The length of the packaging bag 1 in the left-right direction is, for example, 140~240mm, preferably 160~220mm. Specifically, this length can be 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, or 240mm, or any two values ​​listed herein. If this value is too small, the contents may adhere to the inner surface of the packaging bag 1 during filling, making it difficult to fill. This problem is particularly noticeable when the contents are highly viscous. The value of [length of the packaging bag 1 in the vertical direction / length of the packaging bag 1 in the left-right direction] is, for example, 1.5~5, preferably 2~4. Specifically, this value can be 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5, or any two values ​​listed herein.

[0039] like Figure 3A , Figure 3B As shown, the longitudinal sealing portion 7 can be formed by bending the film 2 into a cylindrical shape, aligning the inner surface of one edge 2a side of the film 2 with the inner surface of the other edge 2b side to form a clasped portion 8, and fusing the film 2 together at the clasped portion 8. The longitudinal sealing portion 7 can be formed integrally with the clasped portion 8, or an unsealed portion 8a can be provided in a part of the clasped portion 8. The unsealed portion 8a is preferably set as the edge 8b that includes the clasped portion 8. The part of the packaging bag 1 other than the clasped portion 8 is the main body portion 9. The main body portion 9 is bag-shaped.

[0040] The clasped portion 8 is preferably tilted toward one edge 1a of the packaging bag 1. The side surface of the clasped portion 8 on the main body portion 9 may or may not be welded to the outer surface of the main body portion 9.

[0041] The lengths of the clasping portion 8 and the longitudinal sealing portion 7 in the left-right direction are, for example, 5 to 50 mm, preferably 10 to 30 mm. Specifically, these lengths are, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 mm, or any two values ​​listed herein. The value of {length of the longitudinal sealing portion 7 in the left-right direction / length of the clasping portion 8 in the left-right direction} is, for example, 0.2 to 1.0, preferably 0.5 to 1.0. Specifically, these values ​​are, for example, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0, or any two values ​​listed herein.

[0042] The upper horizontal sealing portion 4 and the lower horizontal sealing portion 5 are respectively provided on the upper and lower sides of the sealing cylinder 3. The horizontal sealing portions 4 and 5 are preferably formed along the upper and lower ends of the cylinder 3, respectively. The horizontal sealing portions 4 and 5 are preferably formed orthogonal to the longitudinal sealing portion 7. The horizontal sealing portions 4 and 5 can be formed by heat sealing the cylinder 3.

[0043] In one example, the transverse seals 4 and 5 consist of a plurality of linear seals arranged in the vertical direction. Figure 1 The linear sealing portions 4a and 5a (shown by the dashed lines) constitute the sealing portions. Each linear sealing portion 4a and 5a extends in the left-right direction of the transverse sealing portions 4 and 5. The plurality of linear sealing portions 4a and 5a are preferably arranged in parallel. The spacing between the linear sealing portions 4a and 5a is preferably 2 to 5 mm. Specifically, this spacing is, for example, 2, 2.5, 3, 3.5, 4, 4.5, or 5 mm, or it can be within any range of two values ​​exemplified here.

[0044] A tear initiation portion 6 is provided in the clasped portion 8. The tear initiation portion 6 is configured to easily tear the clasped portion 8, for example, by forming a cut or notch. The tear initiation portion 6 is preferably positioned to extend from the edge 8b of the clasped portion 8 to the longitudinal sealing portion 7. The ratio of the left-right length of the tear initiation portion 6 to the left-right length of the clasped portion 8 is, for example, 0.1 to 0.9, preferably 0.3 to 0.7. Specifically, this value is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9, or may be within any range of two values ​​exemplified herein.

[0045] The vertical length of the upper horizontal sealing portion 4 from the inner edge 4b ​​to the tear initiation portion 6 is, for example, 0 to 50 mm, preferably 5 to 30 mm. If this value is too small, it will be difficult to start tearing at the tear initiation portion 6; if this value is too large, the length of the opening formed from the tear initiation portion 6 in the vertical direction will be too short, making it difficult to remove the contents.

[0046] The portion of the packaging bag 1 near the horizontal sealing portions 4 and 5 is less prone to expansion, resulting in a flat shape that hinders its rolling conveyance. This tendency is particularly pronounced when the inner edges of the horizontal sealing portions 4 and 5 do not have outwardly protruding curved portions, or when curved portions are present but their lateral length is small.

[0047] Therefore, in this embodiment, left-bent portions 4l, 5l and right-bent portions 4r, 5r protruding outward are provided at both ends of the inner edge of the transverse sealing portions 4, 5. Furthermore, when the length of the transverse sealing portions 4, 5 in the left-right direction is set to Ws, and the lengths of the left-bent portions 4l, 5l and the right-bent portions 4r, 5r in the left-right direction are set to Wl, Wr, Wr, and Ws respectively, Wr / Ws and Wl / Ws are 0.1 to 0.4. By forming such bending portions, as... Figure 2As shown, near the horizontal sealing portions 4 and 5, the packaging bag 1 also easily expands, and its shape is roughly cylindrical, thus making the rolling conveying of the packaging bag 1 smooth. Preferably, Wr and Wl are the same, but they can also be different from each other. Specifically, Wr / Ws and Wl / Ws are, for example, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, or any two values ​​exemplified herein. Ws is the same length as the packaging bag 1 in the left-right direction. Wl and Wr are, for example, 10~100 mm, preferably 20~50 mm. Specifically, Wl and Wr are, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 mm, or any two values ​​exemplified herein.

[0048] Furthermore, the left curved portions 4l and 5l and the right curved portions 4r and 5r are preferably arc-shaped, and when their radii of curvature are set to Rl and Rr, Rl / Ws and Rr / Ws are preferably 0.1 to 0.4, respectively. Specifically, Rl / Ws and Rr / Ws are, for example, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, and 0.4, or any two values ​​exemplified herein. Rl and Rr are, for example, 20 to 60 mm, preferably 30 to 50 mm. Specifically, Rl and Rr are, for example, 20, 25, 30, 35, 40, 45, 50, 55, and 60 mm, or any two values ​​exemplified herein.

[0049] The packaging bag 1, filled with its contents, is roughly oval-shaped. For example... Figure 3A , Figure 3B As shown, when the packaging bag 1 is filled with contents, the roundness of the cross-section perpendicular to the long side direction D1 at the center of the longitudinal sealing portion 7 is preferably 0.5 or higher. The larger the roundness value, the closer the cross-sectional shape is to a circle. When the inscribed circle diameter and circumscribed circle of the cross-section are directly set as D1 and D2 respectively, the roundness is defined by D1 / D2 in this specification. D1 / D2 is, for example, 0.5 to 1.0, specifically, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, or any two values ​​exemplified here.

[0050] The tear initiation portion 6 is preferably located between the left bend portion 4l and the right bend portion 4r. In this case, if the tear initiation portion 6 is located near the end of the generally elliptical cylindrical packaging bag 1, an opening is formed along almost the entire length of the generally elliptical cylinder, making it easy to remove the contents.

[0051] The membrane 2 is preferably a laminated membrane having a substrate layer and a sealant layer, and more preferably has an adhesive layer between the substrate layer and the sealant layer.

[0052] The substrate layer is configured to be exposed on the outer surface of the packaging bag 1, and the sealant layer is configured to be exposed on the inner surface of the packaging bag 1. The sealant layers are heat-sealed together to form a longitudinal sealing portion 7 and a transverse sealing portion 4, 5.

[0053] The substrate layer is formed of a material with excellent strength and high impact resistance. Examples of substrate layers include polyamide (nylon), polyolefin, and polyethylene. The adhesive layer is used to bond the substrate layer and the sealant layer in a stacked manner. Examples of adhesive layers include polyethylene.

[0054] The polyamide in the substrate layer preferably contains an aromatic polyamide. In this case, the substrate layer exhibits linear cleavage in the MD direction and excellent barrier properties. There are no particular limitations on the aromatic polyamide used; resins containing at least 70 mol% of polyamide constituent units composed of phenylenediamine and α,ω-aliphatic dicarboxylic acids with 6 to 12 carbon atoms in their molecular chains can be used. Specifically, examples include homopolymers such as poly(m-phenylene adipamide), poly(m-phenylene heptaylene), poly(m-phenylene azelaylene), poly(terephthalamide azelaylene), and poly(terephthalamide sebacate); and copolymers such as adipoylm-phenylene / adipoyl terephthalamide copolymers, pimecroylm-phenylene / pimecroyl terephthalamide copolymers, azelaylm-phenylene / azelayl terephthalamide copolymers, and sebacate / sebacate terephthalamide copolymers. However, considering its superior basic properties such as strength and gas barrier properties, as well as its relatively easy availability in industry, poly(m-phenylene adipamide) (hereinafter referred to as "MXD6") is preferred.

[0055] The sealant layer can be formed from a resin with excellent heat-sealing properties. For example, it can be formed from polyethylene (e.g., linear low-density polyethylene). As a film constituting the sealant layer, it preferably has linear cutability in the MD direction (longitudinal sealing direction).

[0056] Furthermore, it is preferable that at least one of the substrate layer and the sealant layer has linear cutting capability. This allows for easy, straight tearing of the film 2. The thickness of the sealant layer is preferably at least twice the thickness of the substrate layer, and more preferably at least half the overall thickness of the film 2.

[0057] Membrane 2 can be formed by stacking a substrate layer with a thickness of 10μm to 20μm, for example 15μm, an adhesive layer with a thickness of 10μm to 30μm, for example 20μm, and a sealant layer with a thickness of 30μm to 50μm, for example 40μm. Membrane 2 typically has a thickness of 50μm to 100μm.

[0058] Furthermore, the substrate layer and the sealant layer are laminated and bonded together by an adhesive layer. For example, polyethylene can be used as the adhesive layer, and the substrate layer and sealant layer are bonded together using an extrusion lamination method. Alternatively, materials other than polyethylene can be used as the adhesive layer, and the substrate layer and sealant layer can be bonded together using a dry lamination method. Alternatively, they can be fused together without using an adhesive layer. In this way, the film 2 formed by the substrate layer, adhesive layer, and sealant layer possesses high strength, impact resistance, sealing performance, and gas barrier properties.

[0059] When the tear strength of membrane 2 in the long side direction D1, i.e., the first tear strength, is defined as S1, and the tear strength in the orthogonal direction D2, i.e., the second tear strength, is defined as S2, the ratio of S2 / S1 is 1.5 to 10, preferably 2 to 6. The tear strength can be measured according to JIS K7128. Tear strength is an indicator of the magnitude of the force required to tear membrane 2; the higher the tear strength value, the more difficult it is to tear membrane 2. S2 / S1 is an indicator of the degree to which it is more difficult to tear in the orthogonal direction D2 compared to the long side direction D1; the higher this value, the easier it is to tear membrane 2 in the long side direction D1. Furthermore, the value of S2 / S1 affects the tearing pattern of membrane 2 when tearing begins from the tear initiation point 6.

[0060] Grasp both sides of the tear initiation section 6 with both hands, widening the distance between your hands along the long side of the longitudinal sealing section 7, as follows: Figure 4A , Figure 4B As shown by the single-dotted line 12, the clasped portion 8 is torn. After the tear reaches the main body 9, as shown by single-dotted lines 13 and 14, the tear extends obliquely to both sides across the clasped portion 8, and then travels in a direction almost parallel to the long side direction D1. Therefore, a wide opening is formed in the middle region 15 between single-dotted lines 13 and 14, through which the contents of the packaging bag 1 can be easily removed.

[0061] In the initial stage of tearing, the angle α of the tear extension direction (i.e., the extension direction of the dashed lines 13 and 14) relative to the long side direction D1 is affected by the value of S2 / S1. The larger S2 / S1 is, the smaller the angle α is. If S2 / S1 is too small, the angle α is too large, causing membrane 2 to crack circumferentially, making it difficult to extend to a wider opening in the long side direction D1. If S2 / S1 is too large, the angle α is too small, resulting in an opening that is too narrow, making it difficult to remove the contents.

[0062] Specifically, S2 / S1 can be, for example, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, or any range between any two values ​​listed here.

[0063] When the width at the part where the width of the middle region 15 reaches the maximum is set as Wc, Wc / Ws is, for example, 0.3 to 1.0, preferably 0.4 to 0.8. Specifically, for example, it is 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, and it can also be within the range between any two values exemplified here. If this value is too small, it is difficult to take out the content. If this value is too large, it is difficult to form an opening that extends over a relatively wide range in the long side direction D1.

[0064] 2. Bag-making and filling method Next, use Figures 5-9 The bag-making and filling method using the film 2 will be described. This method can be implemented using a vertical bag-making and filling machine 101.

[0065] <S1: Film bending process> First, the film 2 released from the roll-shaped film roll F is guided to the forming machine 112 via a plurality of release rollers 120, 121. A sensor 119 is provided midway on the route from the roll-shaped film roll F to the forming machine 112 to detect the registration marks printed on the film 2 at constant intervals in the length direction, and release a constant length of the film 2 onto the track of the bag-making and filling machine 101 at constant time intervals. The film 2 is bent into a tubular shape during the process of passing through the forming machine 112, and the inner surface on one edge 2a side of the film 2 coincides with the inner surface on the other edge 2b side to form a clasping portion 8.

[0066] It should be noted that a printing process for printing on the film 2 can be provided at a position near the forming machine 112. This printing is preferably performed in the area that becomes the front surface (the surface on the side of the longitudinal seal portion 7) of the packaging bag 1. At this time, when the packaging bag 1 that falls onto the conveyor belt 130 in the subsequent cutting process is conveyed with the longitudinal seal portion 7 facing upward, it is possible to confirm whether the printing is appropriate.

[0067] <S2: Longitudinal seal process> Next, heat sealing is performed using a longitudinal sealer 113 to form a longitudinal seal portion 7. The longitudinal sealer 113 has a pair of sealing rollers. At the timing when the film 2 moves at a constant time interval, the pair of sealing rollers clamp the clasping portion 8 of the film 2, and at the same time, the pair of sealing rollers rotate in opposite directions to each other, thereby performing heat sealing while feeding the film 2. Thus, the longitudinal seal portion 7 is formed. By forming the longitudinal seal portion 7 on the film 2, a cylindrical body 3 is formed. A tear start portion 6 can be formed on the clasping portion 8 using a cutter 131 disposed downstream of the longitudinal sealer 113. The tear start portion 6 can also be formed after the bag-making and filling is completed.

[0068] <S3: Transverse seal process> Next, by rotating the feed roller 114, the cylindrical body 3 is moved downstream by a predetermined length, as Figure 6As shown, a horizontal sealing machine 116 is used to thermally seal a specified position of the cylindrical body 3 to form a horizontal seal portion 11. The horizontal seal portion 11 is composed of an upper horizontal seal portion 4 of the downstream-side packaging bag 1 and a lower horizontal seal portion 5 of the upstream-side cylindrical body 3, and is divided into upper and lower parts in the subsequent cutting process. The horizontal sealing machine 116 includes a pair of sealing rods 116a, and thermally seals by clamping the specified position with the pair of sealing rods 116a for a specified time.

[0069] In one example, the sealing rod 116a has a shape in which ridges and grooves extending in the left-right direction are alternately arranged in the up-down direction. At this time, linear seal portions (the portions shown by the dotted lines in Figure 1 ) 4a and 5a are formed at the portions where the ridges are pressed. Figure 1

[0070] <S4: Cutting Process> Next, the feed roller 114 is further rotated to move the horizontal seal portion 11 to the position of the cutting press 118. The cutting press 118 includes a pair of press blocks 118a.

[0071] Next, as Figure 7 shown, the cutting press 118 is closed to clamp and cool the horizontal seal portion 11, and the horizontal seal portion 11 is cut with a cutting edge (not shown) into upper and lower parts to form the upper horizontal seal portion of the downstream-side packaging bag 1 and the lower horizontal seal portion 5 of the upstream-side cylindrical body 3. After cutting the horizontal seal portion 11, the downstream-side packaging bag 1 drops onto the conveyor belt 130.

[0072] <S5: Filling Process> Next, as Figure 7 shown, the flattening roller 115, which was in a closed state in the previous process, is opened, and the content W that was put into the hopper 111 and accumulated on the upper side of the flattening roller 115 in the previous process drops to the lower side of the flattening roller 115. Since the lower horizontal seal portion 5 is formed on the cylindrical body 3, the dropped content W fills into the cylindrical body 3. A pair of opening / closing members 123 are arranged around the cylindrical body 3. The opening / closing members 123 are configured to be movable in the horizontal and vertical directions.

[0073] When the content W is further put into the cylindrical body 3 and the content W in the cylindrical body 3 reaches the position of the sensor 122, as Figure 8 shown, the flattening roller 115 is closed, thereby separating the content W into an upper portion and a lower portion on the lower side of the flattening roller 115. The content in the lower portion of the flattening roller 115 is the content for one bag of the packaging bag 1. In addition, a sealing portion 3a is formed on the cylindrical body 3 by closing the flattening roller 115, and a portion that houses the content between the sealing portion 3a and the lower horizontal seal portion 5, that is, a bag portion 3b, is formed.

[0074] <S6: Feeding Process> Next, with the closing and flattening roller 115 in the closed state, the feeding roller 114 is rotated, as Figure 8 shown, to move the sealing portion 3a to the position of the opening / closing member 123.

[0075] <S7: Insertion Process> Next, as Figure 9 shown, the opening / closing member 123 is moved horizontally to insert the sealing portion 3a above the bag portion 3b therein, and the opening / closing member 123 is further moved downward in the vertical direction (refer to the arrow in Figure 9 ), so that the bag portion 3 can be tensioned. Here, the opening / closing member 123 is preferably moved below the horizontal sealer 116. This enables horizontal sealing to be performed while maintaining the tension of the bag portion 3b.

[0076] Thereafter, by performing the horizontal sealing process (S3) while maintaining the opening / closing member 123 above the bag portion 3b, a horizontal sealing portion 11 can be formed at a position (sealing portion 3a) higher than the portion (bag portion 3b) filled with the content W while maintaining the tension of the bag portion 3b, thereby forming the packaging bag 1.

[0077] Then, as Figure 7 shown, the opening / closing member 123 returns to its original position, and the subsequent cutting process (S4) is performed. Thus, as Figure 7 shown, the packaging bag 1 falls onto the conveyor belt 130.

[0078] In this way, by repeating the processes of S3 to S7, the packaging bag 1 filled with the content W can be continuously manufactured. It should be noted that in the manufacture of the packaging bag 1 in the present embodiment, no heat treatment process is performed.

[0079] In the above bag-making and filling method of the present embodiment, the packaging bag 1 is tensioned by performing the above insertion process on the cylinder 3.

[0080] 3. Other Embodiments In the above embodiment, the opening / closing member 123 is moved downward in the vertical direction, but it is not limited to this method. For example, with the cylinder 3 sandwiched between the opening / closing members 123, the cylinder 3 can also be tensioned by moving the cylinder 3 upward in the vertical direction. In this way, by changing the relative positions of the opening / closing members 123 sandwiching the cylinder 3 and the cylinder 3 in the vertical direction, the same effect as the above embodiment can be obtained.

[0081] (Second Viewpoint) 1. Packaging Bag 1 As Figure 10As shown, a packaging bag 1 according to one embodiment of the present invention includes a cylindrical body 3 formed by forming a longitudinal sealing portion 7 on a multi-layered film 2, an upper transverse sealing portion 4, and a lower transverse sealing portion 5. The various sealing portions are formed by heat-sealing the opposing inner surfaces of the film 2 together. The packaging bag 1 is typically filled with contents. Figure 10 For convenience, packaging bag 1 is shown in its unfilled state. Examples of contents are as described in the first point.

[0082] The following is based on Figure 10 The top, bottom, left, and right sides refer to the top, bottom, left, and right of the packaging bag 1. Specifically, the axis of the cylinder 3 is the top and bottom direction, and the left and right sides of the packaging bag 1 are when the longitudinal sealing part 7 is positioned near the front. In addition, the side of the longitudinal sealing part 7 is considered the front, and the side opposite it is considered the back.

[0083] The length of the packaging bag 1 in the left-right direction is, for example, 140~400mm, preferably 160~300mm. Specifically, this length can be, for example, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, or 400mm, or within any two values ​​listed here. If this value is too small, the contents may adhere to the inner surface of the packaging bag 1 during bag making and filling, making it difficult to fill. This problem is particularly noticeable when the contents are highly viscous. The value of [length of the packaging bag 1 in the vertical direction / length of the packaging bag 1 in the left-right direction] is, for example, 1.1~5, preferably 2~4. Specifically, this value can be, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5, or it can be within the range of any two values ​​listed here.

[0084] The upper horizontal sealing portion 4 and the lower horizontal sealing portion 5 are respectively configured to cover the upper and lower sides of the cylinder 3. Preferably, the upper horizontal sealing portion 4 and the lower horizontal sealing portion 5 are formed along the upper and lower ends of the cylinder 3, respectively. Preferably, the upper horizontal sealing portion 4 and the lower horizontal sealing portion 5 are formed orthogonally to the longitudinal sealing portion 7.

[0085] The longitudinal sealing portion 7 is provided in the clasped portion 8, formed by bending the membrane 2 into a cylindrical shape so that the inner surfaces of the two side edges of the membrane 2 overlap each other. The clasped portion 8 is inclined toward one side edge 1c. In the following text, a plan view refers to, as shown... Figure 10 As shown, the packaging bag 1 is laid flat with no contents inside, and viewed from a direction perpendicular to the main surface 1b of the packaging bag 1 in this state.

[0086] When the length of the packaging bag 1 in the left-right direction is set as L, and the length of the clasping part 8 in the left-right direction is set as L1, L1 / L is preferably 0.3 to 0.1. Specifically, L1 / L is, for example, 0.1, 0.15, 0.2, 0.25, 0.3, or any two values ​​exemplified here.

[0087] The upper horizontal sealing portion 4 is provided with an opening portion 16. The opening portion 16 is a part that is processed to make the packaging bag 1 easy to open, such as a part of the film 2 that has been cut (e.g., a cut, a slit), or a part of the film 2 that is processed to make it easy to cut (e.g., a half-cut, a perforated line). When the opening portion 16 is the former, the film 2 may be accidentally torn at the opening portion 16, so it is preferable that the opening portion 16 is the latter. The perforated line is easy to form, so it is even more preferable that the opening portion 16 is a perforated line.

[0088] On the upper horizontal sealing portion 4, an unsealed non-sealed portion 19 is formed on the left side of the opening portion 16 in the left-right direction (i.e., the central side of the packaging bag 1 in the left-right direction, hereinafter also referred to as the central side), at a position in the extending direction of the opening portion 16. By forming the non-sealed portion 19 in this way in the extending direction of the opening portion 16, when opening from the opening portion 16, the opening is stopped at the central end 19a of the non-sealed portion 19, which limits the size of the opening. It should be noted that it is preferable that the opening portion 16 and the non-sealed portion 19 are spaced apart from each other. By making the opening portion 16 and the non-sealed portion 19 spaced apart from each other, when the packaging bag 1 is subjected to external impacts, etc., damage near the opening portion 16 of the upper horizontal sealing portion 4 and leakage of contents can be prevented.

[0089] When the length of the opening portion 16 in the left-right direction is set to L3 and the length of the non-sealed portion 19 in the left-right direction is set to L4, L3 / L4 is preferably 0.7 to 1.2. Specifically, L3 / L4 can be, for example, 0.7, 0.8, 0.9, 1.0, 1.1, or 1.2, or it can be within any two values ​​exemplified here.

[0090] The longitudinal sealing portion 7 can be provided as a whole of the clasping portion 8, but there is a problem that the heat sealing time required to form the longitudinal sealing portion 7 increases with the increase of its area. Therefore, the longitudinal sealing portion 7 is preferably provided as a part of the clasping portion 8. When the length of the longitudinal sealing portion 7 in the left-right direction is set as L2, L2 / L1 is preferably 1.0 or less, for example, 0.1 to 1.0, specifically, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, or any two values ​​exemplified here. It should be noted that the clasping portion 8 can also be heat-sealed entirely in the left-right direction with L2 / L1 set to 1.0. The length L2 in the left-right direction of the longitudinal sealing portion 7 is preferably 30 mm or less.

[0091] Unless otherwise specified, the structure of film 2 is the same as that of the first viewpoint. In an embodiment of this viewpoint, as an example, film 2 has a five-layer structure in which a substrate layer is sandwiched between a sealant layer and an adhesive layer is provided between the substrate layer and the sealant layer. A sealing portion is formed by heat-sealing the sealant layers together. In this case, the materials of the sealant layer that forms the inner side of the packaging bag 1 and the sealant layer that forms the outer side can be different.

[0092] Furthermore, the sealant layer can be formed by mixing multiple resins. In particular, combining resins with low compatibility can impart easy-opening properties (easy-peeling properties). Specifically, consider combining the following resin composition A with resin composition B.

[0093] Resin composition A: As the main component, a resin composition selected from at least one of linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-methyl acrylate copolymer, and their ionomers.

[0094] Resin composition B: A resin composition whose main component is polypropylene or polybutene.

[0095] When using membrane 2 for bag filling, the substrate layer does not contact the contents, while the sealant layer does. Therefore, to prevent additives from entering the contents, it is preferable not to add materials that constitute the sealant. This is especially significant when the contents are milk, which is subject to the "Ministry Ordinance on Standards for the Composition of Milk and Dairy Products." On the other hand, for purposes such as improving the softness of membrane 2, additives such as softeners can be added to the substrate layer.

[0096] 2. Variations Figure 11 The packaging bag 1 is shown as a modified example. In this modified example, the non-sealing portion 19 formed on the central side of the opening portion 16 extends to the side edge 1c of the packaging bag 1. With this configuration, when opening from the opening portion 16, the opening is prevented at the side edge 8c of the closing portion 8, thus limiting the size of the opening.

[0097] 3. Manufacturing method of membrane 2 Figure 12 This is a diagram illustrating the blow molding of the film 2 used to obtain the multilayer bag of the present invention. Figure 12Among them, 30 is an extruder for co-extrusion molding, and 31 is a die for blow molding. A plurality of molten resins extruded in a tubular shape from the extruder 30 via the die 31 are inflated by the supply air pipe 32 during the process of being lifted in the vertical direction. The inflated molten resin is air-cooled by the air cooling ring 34 for air cooling, and is flattened and wound around the winding device 33 in sequence through the guide roller 35, the guide plate 38, and the pinch roller 37, obtaining a roll-shaped film roll F in which the tubular film is wound flat. Therefore, in the bag-making and filling method described below, the roll-shaped film roll F is unwound to supply the film 2. Thus, in the present embodiment, by flattening the tubular film, the film 2 formed by laminating the outer film and the inner film with the two edges in the width direction connected is obtained. The outer film and the inner film are respectively the outer and inner films of the roll-shaped film roll F. It should be noted that the film 2 formed by laminating multiple layers can also be manufactured by other methods, for example, it can be manufactured by laminating and pressing multiple independent films.

[0098] Thus, the film 2 of the present embodiment blow-molds the tubular parison extruded by co-extrusion molding and does not have a stretching process. Therefore, a film with a low tensile elastic modulus is formed. Here, in the present embodiment, the blow-up ratio during blow molding is set to be large, and the extrusion speed is set to be low.

[0099] Specifically, the blow-up ratio is preferably 1.0 or more, more preferably 1.5 or more. The draw speed is preferably 100 m / minute or less, more preferably 60 m / minute or less. By setting in this way, the longitudinal tensile elastic modulus Ve in the longitudinal sealing direction of the film 2 and the transverse tensile elastic modulus He in the transverse sealing direction satisfy the relationship of Ve < He. By forming the film 2 under such conditions, when the opening part 16 provided at the upper transverse sealing part 4 opens the packaging bag 1, the film 2 can be prevented from being stretched and being difficult to open. It should be noted that the upper limit value of the transverse tensile elastic modulus He of the film is preferably 1000 MPa. Thus, for a film with a low tensile elastic modulus (i.e., soft), since the film will be stretched when opening, the effects of the present invention can be significantly obtained.

[0100] The value of He - Ve is preferably 1 MPa or more, further preferably 3 MPa or more. This value is, for example, 1 to 100 MPa, specifically, for example, 1, 2, 3, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 MPa, and can also be within the range between any two values exemplified here or any one of them or more. He and Ve are respectively, for example, 300 to 1000 MPa, specifically, for example, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000 MPa, and can also be within the range between any two values exemplified here.

[0101] 4. Bag-making and filling method Next, use Figure 13 A bag-making and filling method using the film 2 will be described. This method can be implemented using a bag-making and filling system 100 equipped with a sterilization device 23, a drying device 27, and a bag-making and filling device 28. The bag-making and filling method of this embodiment includes a sterilization process, a drying process, and a bag-making and filling process. Each process will be described in detail below.

[0102] 4-1. Sterilization process The sterilization process can be implemented using the sterilization device 23. In the sterilization process, the film 2 is sterilized by bringing the film 2 released from the roll-shaped film roll F into contact with a bactericide.

[0103] Specifically, first, the film 2 released from the roll-shaped film roll F is guided to the sterilization device 23 through the roller 24a. A sensor 119 is disposed midway on the route from the roll-shaped film roll F to the sterilization device 23 to detect the registration marks printed on the film 2 at constant intervals in the length direction, and a constant length of the film 2 is released at constant time intervals onto the track of the bag-making and filling system 100. In addition, a transverse sealer is disposed between the roll-shaped film roll F and the sterilization device 23 to perform transverse sealing on the ends in the long side direction (the flow direction of the film 2) of the film 2. On the other hand, the film 2 can also be disposed in the bag-making and filling system 100 in such a manner that the ends in the long side direction of the film 2 do not contact the bactericide. In this case, the transverse sealer between the roll-shaped film roll F and the sterilization device 23 is not required.

[0104] The sterilization device 23 is a device that can sterilize the film 2. It can be a device that sterilizes the film 2 by immersing the film 2 in a sterilizing liquid 23a as a liquid containing a bactericide, or a device that sterilizes the film 2 by bringing the film 2 into contact with the mist or gas of the bactericide. As the bactericide, hydrogen peroxide can be exemplified. Inside the sterilization device 23, the film 2 is guided by the rollers 24b and 24c to move toward the drying device 27.

[0105] A pressing process for pressing the film 2 is performed after the sterilization process and before the bag-making and filling process. Specifically, this process can be performed by pressing the film 2 with a pair of pressing members (such as rollers) 15. By performing the pressing process, the occurrence of defects during bag-making can be reduced. In this embodiment, a pair of pressing members 25 are provided at two locations, and they can also be provided at one location or three or more locations.

[0106] 4-2. Drying process The drying process is performed after the sterilization process and before the bag-making and filling process. By performing this process, even if moisture or bactericide adheres to the film 2 during the sterilization process, it is possible to prevent the accidental mixing of moisture or bactericide into the packaging bag 1.

[0107] In this embodiment, the drying process is performed by a blower 26 and a drying device 27. The blower 26 blows air 26a onto the membrane 2 to remove water droplets from the surface of the membrane 2. The blower 26 is disposed on both sides of the membrane 2 to remove water droplets from both sides of the membrane 2.

[0108] The temperature inside the drying apparatus 27, 27a, is higher than that outside the drying apparatus 27, and the membrane 2 is dried while passing through the inside space 27a. The membrane 2 enters the inside space 27a through the inlet 27b, is guided inside the inside space 27a by rollers 24d, 24e, and 24f, and exits the inside space 27a through the outlet 27c.

[0109] The membrane 2, which leaves the drying device 27, is guided by roller 24g to the forming machine 112.

[0110] 4-3. Bag making and filling process The bag-making and filling process can be carried out using a bag-making and filling device 28. In the bag-making and filling process, the sterilized film 2 is heat-sealed to close the lower end and form a cylindrical body 39. After filling the cylindrical body 39 with the contents W, the upper end of the cylindrical body 39 is heat-sealed to seal it. This process is described in detail below.

[0111] <Step 1: Forming membrane 2 into a tubular shape> The membrane 2 is bent into a cylindrical shape during its passage through the forming machine 112, resulting in a shape in which the two sides of the bent front end overlap. A clamshell portion 8 is formed in the overlapping portion.

[0112] <Step 2 in forming the longitudinal sealing section 7> Next, the palm-shaped portion 8 of the membrane 2 is heat-sealed using a longitudinal sealing machine 113 to form a longitudinal sealing portion 7. The longitudinal sealing machine 113 is equipped with a pair of sealing rods, which, in conjunction with the movement of the membrane 2 at constant time intervals, clamp the palm-shaped portion 8 with the pair of sealing rods for a specified time to perform heat sealing.

[0113] <Step 3 of forming the lower transverse sealing part 5> Next, the freely opening and closing flattening roller 115 is closed to flatten the cylindrical body 39 formed by the film 2. This flattens the cylindrical body 39. Then, a horizontal sealing machine 116 heat-seals a predetermined position of the flattened cylindrical body 39 to form a lower horizontal sealing portion 5. The horizontal sealing machine 116 is equipped with a pair of sealing rods, and heat-sealing is performed by clamping the predetermined position with the pair of sealing rods for a predetermined time. This seals the lower end of the cylindrical body 39.

[0114] <4 steps for filling contents> Next, the flattening roller 115 is turned on, and the specified amount of contents W is fed into the cylindrical body 39 through the hopper 111.

[0115] <Step 5 of forming the upper horizontal sealing part 4> Next, by rotating the feed roller 114, the cylindrical body 39 and the film 2 following it are extended to a predetermined length before separating from the packaging bag 1. The pair of sealing rods of the horizontal sealing machine 116 are closed for a predetermined time to heat-seal at a predetermined position, forming an upper horizontal seal 4, sealing the packaging bag 1, and forming a lower horizontal seal 5 for the next packaging bag located upstream of the track connected to it. In this process, an opening portion 16 is formed on the formed upper horizontal seal 4. It should be noted that the opening portion 16 can be formed simultaneously with the sixth process of cutting the boundary between the lower horizontal seal 5 and the upper horizontal seal 4 that is continuous with it.

[0116] Step 6: Cutting the boundary line of a continuous bag The pressure cutting machine 118 is closed, clamping the lower horizontal sealing part 5 and the upper horizontal sealing part 4 on the lower side of the packaging bag 1 before separation. The boundary between the two is cut off by the cutting blade 118b, so that the packaging bag 1 falls onto the conveyor belt 130. This produces a packaging bag 1 filled with contents W.

[0117] 5. Examples Figure 14 The longitudinal tensile modulus Ve and transverse tensile modulus He (in MPa) of the packaging bag 1 of the embodiment and the packaging bag of the comparative example are shown. The packaging bags of the embodiment and the comparative example are manufactured using the method described in "3. Manufacturing Method of Film 2", with Ve and He varied by changing the blow-up ratio. The tensile modulus can be determined by tensile testing according to JIS K 7127. The test temperature is 23.5°C, the tensile test speed is 50 mm / min, and the test dumbbell shape is No. 5. Figure 14 As shown, Examples 1 to 5 satisfy the relationship that the tensile modulus of elasticity Ve < the tensile modulus of elasticity He. In contrast, in the comparative examples, the tensile modulus of elasticity Ve > the tensile modulus of elasticity He. An experiment was conducted to assess the ease of opening the packaging bags of these examples and comparative examples.

[0118] When the test subject opened the packaging bags 1 of Examples 1 to 5, they were able to open them easily at the opening section 16. In contrast, for the packaging bags shown in the comparative examples, the film around the opening section was constantly stretched, making it difficult for the test subject to open them easily.

[0119] 6. Other implementation methods The layer composition of membrane 2 can be appropriately modified. In the above embodiment, membrane 2 consists of 5 layers, including the adhesive layer, but it can also have fewer or more than 5 layers.

[0120] The sealing method of the longitudinal sealing portion 7 of the packaging bag 1 can be appropriately changed. The clasping portion 8, which forms a clasping fit in the above embodiment, can also be an envelope fit.

[0121] These steps can be omitted if sterilization and drying are not required. Furthermore, the drying process can be performed using only one of the blowing device 26 and the drying device 27, or it can be done through natural drying.

[0122] In the above embodiment, the opening portion is formed in the upper horizontal sealing portion 4, but it is not limited to this method. For example, a laterally extending opening and sealing portion can be provided between the upper horizontal sealing portion 4 and the lower horizontal sealing portion 5 in the vertical direction, and the opening portion is provided in the opening and sealing portion.

[0123]

Example

[0124] Membrane 2 (a 3-layer laminate consisting of a substrate layer, an adhesive layer, and a sealant layer) Substrate layer: Polyamide (manufactured by Unitica Corporation, EMBLEM NC-15, 15μm thick) Adhesive layer: Maleic anhydride modified polyethylene, 5μm thick Sealant layer: LLDPE (SKYFILM Co., LTD, HR543, 50μm thick) Packaging bag 1 The length of packaging bag 1 in the left-right direction is 200mm. The vertical length of packaging bag 1 is 600mm. The left-right length of the clasped part 8: 20mm The length of the longitudinal sealing part 7 in the left-right direction is 10mm. The length of the opening (cut mark) in the left-right direction is 15mm. The vertical length of the upper transverse sealing portion 4 from the inner edge 4b ​​to the tear initiation portion 6 is 5mm. <Comparative Example 1> The membrane 2 of Example 1 was replaced with an isotropic membrane with S2 / S1=1, but the membrane 2 was otherwise manufactured using the same method as in Example 1.

[0125] 2. Opening test For the embodiments In the comparative example, the packaging bag 1 was held with both hands on both sides of the tear initiation portion 6, and the distance between the two hands was widened along the long side of the longitudinal sealing portion 7. The film 2 was torn starting from the tear initiation portion 6, and then the tearing condition of the film 2 was compared.

[0126] In the packaging bag of Example 1, after the clasped portion 8 is torn, the tear spreads obliquely to both sides of the main body portion 9 across the clasped portion. Subsequently, the tear travels in a direction almost parallel to the long side direction D1 of the longitudinal sealing portion 7, and the main body portion 9 is torn to the lower end of the packaging bag 1, forming a relatively wide opening (approximately 10 cm wide) along the long side direction D1.

[0127] In the packaging bag of Comparative Example 1, after the clasp portion 8 is torn, the film 2 is torn in the main body portion 9 in a manner that extends circumferentially along the main body portion 9. Therefore, a wider opening along the long side direction D1 is not formed.

[0128] Symbol Explanation 1: Packaging bag; 1a: One edge; 1b: Main surface; 1c: Side edge; 2: Film; 2a: One edge; 2b: Another edge; 3: Tube body; 3a: Sealed part; 3b: Bag part; 4: Upper horizontal seal; 4a: Linear seal; 4b: Inner edge; 4l: Left bend; 4r: Right bend; 5: Lower horizontal seal; 5a: Linear seal; 5l: Left bend; 5r: Right bend; 6: Tear start; 7: Longitudinal seal; 8: Clasp; 8a: Unsealed part; 8 b: Edge, 8c: Side edge, 9: Main body, 11: Horizontal sealing part, 12: Single dotted line, 13: Single dotted line, 14: Single dotted line, 15: Middle area, 16: Opening part, 19: Non-sealed part, 19a: Central side end, 23: Sterilization device, 23a: Sterilization liquid, 24a: Roller, 24b: Roller, 24c: Roller, 24d: Roller, 24e: Roller, 24f: Roller, 24g: Roller, 25: Pressing part, 26: Blowing device, 26a: Air, 27: Drying device, 27a: internal space, 27b: inlet, 27c: outlet, 28: bag making and filling device, 30: extruder, 31: die head, 32: air supply pipe, 33: winding device, 34: air ring for air cooling, 35: guide roller, 37: pinch roller, 38: guide plate, 39: cylindrical body, 100: bag making and filling system, 101: bag making and filling machine, 111: hopper, 112: forming machine, 113: longitudinal sealing machine, 114: feed roller, 115: roller, 116: transverse sealing machine 116a: sealing rod; 118: pressure cutter; 118a: pressing block; 118b: cutting blade; 119: sensor; 120: discharge roller; 121: discharge roller; 122: sensor; 123: opening and closing component; 130: conveyor belt; 131: cutter; A: resin composition; D1: long side direction; D2: orthogonal direction; F: roll film; He: tensile modulus of elasticity; NC-15: EMBLEM; Ve: tensile modulus of elasticity; W: contents; α: angle.

Claims

1. A packaging bag, wherein, The packaging bag comprises a cylindrical body formed by a longitudinal sealing portion on a film, an upper transverse sealing portion, a lower transverse sealing portion, and a tear initiation portion. The longitudinal sealing portion is formed by bending the membrane into a cylindrical shape and overlapping the inner surfaces of one edge side of the membrane with the inner surfaces of the other edge side to form a clasped portion, where the membranes are fused together. The upper horizontal sealing part is configured to close the upper side of the cylinder. The lower horizontal sealing part is configured to seal the lower side of the cylinder. The tear initiation portion is located at the clasped palm portion. The packaging bag is composed of the clasped portion and the main body portion other than thereon. When the tear strength of the membrane in the longitudinal sealing section along the long side, i.e., the first tear strength, is defined as S1, and the tear strength in the orthogonal direction to the long side, i.e., the second tear strength, is defined as S2, then S2 / S1 is 1.5~10. The packaging bag is filled with contents. The upper transverse sealing portion has a left-curved portion and a right-curved portion convex outward at both ends of its inner edge, and the lower transverse sealing portion has a left-curved portion and a right-curved portion convex outward at both ends of its inner edge. When the packaging bag is filled with contents, the roundness of the cross section perpendicular to the long side direction at the center of the longitudinal seal is 0.5 or more.

2. The packaging bag according to claim 1, wherein, When the length of the upper horizontal sealing part in the left and right directions is set as Ws, and the lengths of the left and right curved parts in the left and right directions are set as Wl and Wr respectively, Wr / Ws and Wl / Ws are both 0.1~0.

4.

3. The packaging bag according to claim 2, wherein, The left and right curved portions are arc-shaped, and when their radii of curvature are set to Rl and Rr, Rl / Ws and Rr / Ws are both 0.1~0.

4.

4. The packaging bag according to claim 1, wherein, The tear initiation portion is located between the left curved portion and the right curved portion of the upper transverse sealing portion.

5. The packaging bag according to claim 1, wherein, In the long side direction, the length from the inner edge of the upper transverse seal to the tear initiation portion is 5~30mm.

6. The packaging bag according to claim 1, wherein, The packaging bag is oval-cylindrical in shape when filled with the contents.

7. The packaging bag according to claim 1, wherein, The side of the cylinder does not have an inward folding section.

8. The packaging bag according to claim 1, wherein, In the packaging bag, at a position higher than the portion filled with the contents, the upper horizontal seal is formed while maintaining the tension of the packaging bag.

9. The packaging bag according to claim 1, wherein, S2 / S1 is 2~6.

10. The method for opening a packaging bag according to any one of claims 1 to 9, wherein, The process includes the following steps: Grasp both sides of the tear initiation portion with both hands, widening the distance between the hands along the long side of the longitudinal sealing portion, thereby initiating the tearing process of the membrane at the tear initiation portion. The process of tearing the clasped portion. After the tear reaches the main body, the tear extends obliquely to both sides of the main body, passing through the clasped portion. Subsequently, the tear is made to travel in the direction along the long side of the longitudinal seal to form an opening.

11. The method for opening a packaging bag according to claim 10, wherein, When the width of the middle region formed by the tear extending obliquely to the side reaches its maximum, Wc is defined as the width of the part where the width reaches its maximum, and the length of the upper transverse sealing part in the left and right direction is defined as Ws, Wc / Ws is 0.4~0.

8.

12. The method for opening a packaging bag according to claim 10, wherein, The contents are a viscous food product. The method also includes the step of removing the contents of the packaging bag through the opening.

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