Packaging bag and its opening method

Abstract

To provide a packaging bag which is easy to manufacture and can form a wide opening part.SOLUTION: A packaging bag includes a cylindrical body constituted by forming a vertical sealing part on a film, an upper horizontal sealing part, a lower horizontal sealing part, and a tear initiation part. The vertical sealing part is formed by welding the films together at a joint part formed by bending the film into a cylindrical shape and overlapping an inner surface of one edge side and an inner surface of the other edge side of the film. The upper horizontal sealing part is provided so as to close the upper side of the cylindrical body. The lower horizontal sealing part is provided so as to close the lower side of the cylindrical body. The tear initiation part is provided at the joint part. The packaging bag is constituted of the joint part and a body part other than the joint part. In the film, when a first tear strength that is a tear strength in a longitudinal direction of the vertical sealing part is S1, and a second tear strength that is a tear strength in an orthogonal direction perpendicular to the longitudinal direction is S2, S2 / S1 is between 1.5 and 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a packaging bag. [Background technology]

[0002] Patent Document 1 discloses a packaging bag in which a continuous linear opening slit is formed in the middle layer parallel to the back heat-sealed part, and a wide opening can be formed by opening the bag along the opening slit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-254800 A Summary of the Invention [Problem to be solved by the invention]

[0004] To manufacture a packaging bag having the structure described in Patent Document 1, it is necessary to form an opening slit in the film constituting the intermediate layer, and then laminate this film with another film, which is time-consuming to manufacture.

[0005] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a packaging bag which is easy to manufacture and capable of forming a wide opening. [Means for solving the problem]

[0006] According to the present invention, there is provided a packaging bag, the packaging bag comprising a cylindrical body formed by forming a vertical seal portion in a film, an upper horizontal seal portion, a lower horizontal seal portion, and a tear initiation portion, the vertical seal portion being formed by bending the film into a cylindrical shape and overlapping the inner surface of one edge side and the inner surface of the other edge side of the film to weld the films together at a seam portion formed by folding the film into a cylindrical shape and overlapping the inner surface of one edge side and the inner surface of the other edge side of the film, the upper horizontal seal portion is arranged to close the upper side of the cylindrical body, the lower horizontal seal portion is arranged to close the lower side of the cylindrical body, the tear initiation portion is arranged at the seam portion, the packaging bag is composed of the seam portion and a main body portion other than the seam portion, and the film has a first tear strength S1, which is the tear strength in the longitudinal direction of the vertical seal portion, and a second tear strength S2, which is the tear strength in a perpendicular direction perpendicular to the longitudinal direction, such that S2 / S1 is 1.5 to 10.

[0007] The packaging bag of the above configuration is formed of a film with S2 / S1 of 1.5 to 10. Therefore, when both sides of the tear initiation part are pinched with both hands and the distance between the hands is widened along the longitudinal direction of the vertical seal part, tearing starts at the tear initiation part, and after the tear reaches the main body part, the tear spreads diagonally to both sides across the joint part and proceeds in the longitudinal direction of the vertical seal part, so that a wide opening can be formed by the tearing. In addition, since there is no need to form an opening slit in the film constituting the intermediate layer as in Patent Document 1, manufacturing is easy.

[0008] Various embodiments of the present invention will be described below. The embodiments described below can be combined with each other. Preferably, the packaging bag is the above-described packaging bag, in which S2 / S1 is 2-6. Preferably, the packaging bag described above has a circularity of 0.5 or more in a cross section perpendicular to the longitudinal direction at the longitudinal center of the vertical seal portion when the packaging bag is filled with contents. [Brief description of the drawings]

[0009] [Figure 1]FIG. 2 is a plan view of the packaging bag 1 with no contents inside. [Diagram 2] FIG. 1 is a perspective view of a packaging bag 1 with contents inside. [Diagram 3] Figure 3A is a cross-sectional view perpendicular to the longitudinal direction D1 at the center of the longitudinal direction D1 of the vertical seal portion 7 when the contents are filled in the packaging bag 1, and Figure 3B is an enlarged view of area B in Figure 3A. [Figure 4] FIG. 4A is a perspective view showing the line along which film 2 is torn when tearing of film 2 begins from tear initiation portion 6, and FIG. 4B is an enlarged view of region B in FIG. 4A. [Diagram 5] FIG. 1 is a configuration diagram of a bag making and filling machine 100. [Figure 6] 1 is an enlarged view of the vicinity of a transverse sealing machine 116 of a bag making and filling machine 100, showing a state in which a transverse seal portion 11 is being formed by the transverse sealing machine 116. FIG. [Figure 7] From the state shown in Figure 6, the horizontal sealing machine 116 opens, the shutter member 123 returns to its initial position, the horizontal sealing section 11 moves to the position of the press / cutter 118, the press / cutter 118 clamps the horizontal sealing section 11 and cuts it, and then the press / cutter 118 and the squeezing roll 115 open. [Figure 8] 7, the squeeze roll 115 is closed after the contents W are further added, and then the contact portion 3a moves to the position of the shutter member 123. FIG. [Figure 9] 8, the shutter member 123 sandwiches the contact portion 3a and moves vertically downward in this state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described. Various features shown in the following embodiments can be combined with each other. Also, each feature can be an invention independently.

[0011] 1. Packaging bag 1 As shown in Figures 1 to 4, a packaging bag 1 according to one embodiment of the present invention comprises a cylinder 3 formed by forming a vertical seal portion 7 on a film 2, an upper horizontal seal portion 4, a lower horizontal seal portion 5, and a tear initiation portion 6. The packaging bag 1 is usually filled with contents, but for convenience, Figure 1 shows the packaging bag 1 in a state where no contents are filled. Examples of contents include viscous foods such as flower paste, jam, and bean paste.

[0012] In the following description, the top, bottom, left and right of Fig. 1 refer to the top, bottom, left and right of the packaging bag 1. Specifically, the axial direction of the cylinder 3 corresponds to the top and bottom direction. The left and right sides of the packaging bag 1 correspond to the left and right sides when the vertical seal portion 7 is disposed at the front side. The surface on the vertical seal portion 7 side is referred to as the front side, and the opposing surface is referred to as the back side. The top and bottom direction corresponds to the longitudinal direction D1 of the vertical seal portion 7, and the left and right direction corresponds to the orthogonal direction D2 perpendicular to the longitudinal direction D1.

[0013] The length of the packaging bag 1 in the left-right direction is, for example, 140 to 240 mm, and preferably 160 to 220 mm. This length is, for example, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, and 240, and may be within a range between any two of the numerical values ​​exemplified 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 prominent when the viscosity of the contents is high. The value of [vertical length of packaging bag 1 / left-right length of packaging bag 1] is, for example, 1.5 to 5, and preferably 2 to 4. This value is, for example, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5, and may be within a range between any two of the numerical values ​​exemplified here.

[0014] As shown in Fig. 3, the vertical seal 7 is formed by bending the film 2 into a cylindrical shape and welding the film 2 together at a seam 8 formed by overlapping the inner surface of one edge 2a of the film 2 with the inner surface of the other edge 2b. The vertical seal 7 may be formed over the entire seam 8, or an unsealed portion 8a may be provided in part of the seam 8. It is preferable that the unsealed portion 8a is provided so as to include the edge 8b of the seam 8. The portion of the packaging bag 1 other than the seam 8 is the main body 9. The main body 9 is bag-shaped.

[0015] It is preferable that the joint portion 8 is folded down toward one edge 1a of the packaging bag 1. The surface of the joint portion 8 facing the main body portion 9 may or may not be welded to the outer surface of the main body portion 9.

[0016] The length in the left-right direction of each of the joint portion 8 and the vertical seal portion 7 is, for example, 5 to 50 mm, and preferably 10 to 30 mm. Specifically, this length is, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 mm, and may be within a range between any two of the numerical values ​​exemplified here. The value of {left-right length of the vertical seal portion 7 / left-right length of the joint portion 8} is, for example, 0.2 to 1.0, and preferably 0.5 to 1.0. Specifically, this value is, for example, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0, and may be within a range between any two of the numerical values ​​exemplified here.

[0017] The upper horizontal seal portion 4 and the lower horizontal seal portion 5 are provided so as to close the upper and lower sides, respectively, of the cylindrical body 3. The horizontal seal portions 4, 5 are preferably formed along the upper and lower ends, respectively, of the cylindrical body 3. The horizontal seal portions 4, 5 are preferably formed so as to be perpendicular to the vertical seal portion 7. The horizontal seal portions 4, 5 can each be formed by heat-sealing the cylindrical body 3.

[0018] In one example, the horizontal seal portions 4, 5 are composed of a plurality of linear seal portions 4a, 5a (areas indicated by dotted lines in FIG. 1) aligned in the vertical direction. Each linear seal portion 4a, 5a is provided so as to extend in the left-right direction of the horizontal seal portions 4, 5. The linear seal portions 4a, 5a are preferably arranged in parallel. The linear seal portions 4a, 5a are preferably provided at a pitch of 2 to 5 mm. Specifically, this pitch is, for example, 2, 2.5, 3, 3.5, 4, 4.5, or 5 mm, and may be within a range between any two of the numerical values ​​exemplified here.

[0019] The tear initiation portion 6 is provided in the joint portion 8. The tear initiation portion 6 is a portion configured to facilitate tearing of the joint portion 8, and is configured by, for example, a notch or a cut. The tear initiation portion 6 is preferably provided so as to reach the vertical seal portion 7 from the edge 8b of the joint portion 8. {The left-right length of the tear initiation portion 6 / the left-right length of the joint portion 8} is, for example, 0.1 to 0.9, and preferably 0.3 to 0.7. Specific examples of this value are 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9, and may be within a range between any two of the numerical values ​​exemplified here.

[0020] The vertical length from the inner edge 4b ​​of the upper horizontal seal 4 to the tear initiation part 6 is, for example, 0 to 50 mm, and preferably 5 to 30 mm. If this value is too small, it is difficult to start tearing at the tear initiation part 6, and if this value is too large, the vertical length of the opening formed starting from the tear initiation part 6 becomes too short, making it difficult to remove the contents.

[0021] In areas of the packaging bag 1 near the horizontal seal portions 4, 5, the packaging bag 1 is less likely to expand, causing the packaging bag 1 to assume a flat shape, which hinders rolling transport of the packaging bag 1. This tendency is particularly noticeable when the inner edges of the horizontal seal portions 4, 5 are not provided with curved portions that convex outward at both ends, or when curved portions are provided but their length in the left-right direction is short.

[0022] In this embodiment, the left curved portions 4l, 5l and the right curved portions 4r, 5r are provided at both ends of the inner edge of the horizontal seal portions 4, 5, which are convex toward the outside. In addition, if the horizontal seal portions 4, 5 have a left-right length Ws and the left-right lengths of the left curved portions 4l, 5l and the right curved portions 4r, 5r Wl, Wr, Wr / Ws and Wl / Ws are set to 0.1 to 0.4, respectively. By forming such curved portions, as shown in FIG. 2, the packaging bag 1 is easily expanded even in the vicinity of the horizontal seal portions 4, 5, and the outer shape becomes approximately cylindrical, so that the rolling and conveying of the packaging bag 1 becomes smooth. It is preferable that Wr and Wl are the same, but they may 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, and 0.4, and may be within a range between any two of the numerical values ​​exemplified here. Ws is the same as the length of the packaging bag 1 in the left-right direction. Wl and Wr are, for example, 10 to 100 mm, and preferably 20 to 50 mm. Specifically, Wl and Wr are, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mm, and may be within a range between any two of the numerical values ​​exemplified here.

[0023] In addition, the left curved portion 4l, 5l and the right curved portion 4r, 5r are preferably arc-shaped, and when the radii of curvature are Rl, Rr, Rl / Ws and Rr / Ws are preferably 0.1 to 0.4. Specifically, Rl / Ws and Rr / Ws are, for example, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, and may be within a range between any two of the numerical values ​​exemplified here. Rl, Rr are, for example, 20 to 60 mm, and preferably 30 to 50 mm. Specifically, Rl, Rr are, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60 mm, and may be within a range between any two of the numerical values ​​exemplified here.

[0024] The packaging bag 1 filled with the contents is in a substantially elliptical cylindrical shape. As shown in Fig. 3, the circularity of the cross section perpendicular to the longitudinal direction D1 at the center of the longitudinal direction D1 of the vertical seal portion 7 when the contents are filled in the packaging bag 1 is preferably 0.5 or more. The larger the circularity value, the closer the cross-sectional shape is to a circle. In this specification, the circularity is defined as D1 / D2, where D1 and D2 are the inscribed circle diameter and the circumscribed circle diameter in the cross section, respectively. D1 / D2 is, for example, 0.5 to 1.0, specifically, for example, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0, and may be within a range between any two of the numerical values ​​exemplified here.

[0025] It is preferable to provide the tear initiation portion 6 between the left curved portion 4l and the right curved portion 4r. In this case, if the tear initiation portion 6 is provided at a position close to the end of the substantially elliptical cylindrical packaging bag 1, an opening is formed over almost the entire length of the substantially elliptical cylinder, making it easy to remove the contents.

[0026] The film 2 is preferably a laminated film having a base layer and a sealant layer, and more preferably has an adhesive layer between the base layer and the sealant layer.

[0027] The base material layer is disposed so as to be exposed on the outer surface of the packaging bag 1, and the sealant layer is disposed so as to be exposed on the inner surface of the packaging bag 1. The sealant layers are heat-sealed to each other to form the vertical seal portion 7 and the horizontal seal portions 4 and 5.

[0028] The base layer is made of a material having excellent strength and high impact resistance. For example, polyamide, polyolefin, polyethylene, etc. are used as the base layer. The adhesive layer is a layer for adhering the base layer and the sealant layer so as to be laminated together, and for example, polyethylene, etc. are used as the adhesive layer.

[0029] The polyamide of the base layer preferably contains an aromatic polyamide. In this case, the base layer has linear cutting properties in the MD direction and has excellent barrier properties. There are no particular limitations on the aromatic polyamide, but resins containing 70 mol % or more of polyamide structural units consisting of xylylenediamine and α,ω-aliphatic dicarboxylic acid having 6 to 12 carbon atoms in the molecular chain can be used. Specific examples include homopolymers such as polymetaxylylene adipamide, polymetaxylylene pimelamide, polymetaxylylene azelamide, polyparaxylylene azelamide, and polyparaxylylene decanamide, and copolymers such as metaxylylene / paraxylylene adipamide copolymer, metaxylylene / paraxylylene pimelamide copolymer, metaxylylene / paraxylylene azelamide copolymer, and metaxylylene / paraxylylene sepacamide copolymer, with polymetaxylylene adipamide (hereinafter referred to as "MXD6") being preferred as it has excellent basic properties such as strength and gas barrier properties, and is relatively easily available industrially.

[0030] The sealant layer can be formed of a resin having excellent heat sealability. For example, the sealant layer can be formed of linear low-density polyethylene. The film constituting the sealant layer is preferably one having linear cutability in the MD direction.

[0031] In addition, it is preferable that at least one of the base layer and the sealant layer has a straight-line cutting property. The thickness of the sealant layer is preferably at least twice the thickness of the base layer, and is preferably at least half the thickness of the entire film 2.

[0032] The film 2 can be formed by laminating a base layer having a thickness of 10 μm to 20 μm, for example 15 μm, an adhesive layer having a thickness of 10 μm to 30 μm, for example 20 μm, and a sealant layer having a thickness of 30 μm to 50 μm, for example 40 μm, and the film 2 usually has a thickness of 50 μm to 100 μm.

[0033] The base layer and the sealant layer are bonded together by an adhesive layer so as to be laminated together. For example, polyethylene can be used as the adhesive layer, and the base layer and the sealant layer can be bonded together by an extrusion lamination method. A material other than polyethylene can be used as the adhesive layer, and the base layer and the sealant layer can be bonded together by a dry lamination method. Alternatively, fusion without an adhesive layer can be used. The film 2 formed from the base layer, the adhesive layer, and the sealant layer in this way has high strength, impact resistance, sealing properties, airtightness, etc.

[0034] In the film 2, the first tear strength S1 is the tear strength in the longitudinal direction D1, and the second tear strength S2 is the tear strength in the orthogonal direction D2. S2 / S1 is 1.5 to 10, preferably 2 to 6. The tear strength can be measured according to JIS K7128. The tear strength is an index showing the magnitude of the force required to tear the film 2, and the larger the tear strength value, the more difficult it is to tear the film 2. S2 / S1 is an index showing how difficult it is to tear in the orthogonal direction D2 compared to the longitudinal direction D1, and the larger this value, the more easily the film 2 is torn in the longitudinal direction D1. The value of S2 / S1 affects how the film 2 is torn when tearing of the film 2 starts from the tear initiation part 6.

[0035] When both sides of tear initiation portion 6 are pinched with both hands and the distance between the hands is increased along the longitudinal direction of vertical seal portion 7, seam portion 8 is torn as shown in dashed line 12 as shown in Fig. 4. When the tear reaches main body portion 9, the tear spreads diagonally to both sides, sandwiching seam portion 8, as shown by dashed lines 13 and 14, and then the tear progresses in a direction substantially parallel to longitudinal direction D1. As a result, a wide opening is formed in intermediate region 15 between dashed lines 13 and 14, and the contents in packaging bag 1 can be easily removed through this opening.

[0036] The value of S2 / S1 affects the angle α in the initial stage of tearing, which is the direction in which the tear extends with respect to the longitudinal direction D1 (i.e., the direction in which the dashed lines 13 and 14 extend). The larger the S2 / S1, the smaller the angle α. If S2 / S1 is too small, the angle α becomes too large, causing the film 2 to tear circumferentially, making it difficult to form an opening extending over a wide range in the longitudinal direction D1. If S2 / S1 is too large, the angle α becomes too small, causing the width of the opening to become too narrow and making it difficult to take out the contents.

[0037] Specifically, S2 / S1 is, 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, and it may also be within the range between any two of the values exemplified here.

[0038] If the width at the site where the width of the intermediate region 15 is maximum is defined as Wc, then Wc / Ws is, for example, 0.3 to 1.0, preferably 0.4 to 0.8. Specifically, it is, for example, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, and it may also be within the range between any two of the values exemplified here. If this value is too small, it is difficult to take out the contents, and if this value is too large, it becomes difficult to form an opening extending over a wide range in the longitudinal direction D1.

[0039] 2. Bag-making and filling method Next, a bag-making and filling method using the film 2 will be described with reference to FIGS. 5 to 9. This method can be implemented using a vertical bag-making and filling machine 100.

[0040] <S1: Film bending process> First, the film 2 fed out from the roll-shaped web F is guided to the former 112 via a plurality of pay-off rolls 120 and 121. A sensor 119 is arranged in the path from the roll-shaped web F to the former 112, which detects the registration marks printed at regular intervals in the length direction on the film 2, so that the film 2 of a certain length can be sent out at regular time intervals on the track of the bag-making and filling machine 100. While passing through the former 112, the film 2 is curved into a cylindrical shape, and the inner surfaces of one edge 2a side and the other edge 2b side of the film 2 are overlapped to form the clasp part 8.

[0041] In addition, a printing process for printing on the film 2 may be provided at a position in front of the former 112. This printing is preferably performed on the area that will become the front surface (the surface on the side of the longitudinal seal part 7) of the packaging bag 1. In this case, when transporting the packaging bag 1 that has fallen onto the conveyor 130 in the cutting process described later with the longitudinal seal part 7 on the upper side, it is possible to confirm whether the printing is properly performed.

[0042] <S2: Longitudinal sealing process> Next, the longitudinal seal part 7 is formed by heat sealing with the longitudinal sealer 113. The longitudinal sealer 113 includes a pair of seal rolls. In accordance with the timing when the film 2 moves at regular time intervals, while sandwiching the clasp part 8 of the film 2 with the pair of seal rolls, the pair of seal rolls are rotated in opposite directions to each other to perform heat sealing while feeding out the film 2. Thereby, the longitudinal seal part 7 is formed. By forming the longitudinal seal part 7 on the film 2, the cylindrical body 3 is formed. The tear start part 6 can be formed in the clasp part 8 by using a cutter 131 arranged downstream of the longitudinal sealer 113. The tear start part 6 may be formed after the completion of bag-making and filling.

[0043] <S3: Transverse sealing process> Next, by rotating the feed roll 114, the cylindrical body 3 is moved downstream by a predetermined length, and as shown in FIG. 6, a predetermined position of the cylindrical body 3 is heat-sealed by the horizontal sealing machine 116 to form the horizontal seal portion 11. The horizontal seal portion 11 is configured by connecting the upper horizontal seal portion 4 of the downstream packaging bag 1 and the lower horizontal seal portion 5 of the upstream cylindrical body 3, and is vertically divided in the cutting process described later. The horizontal sealing machine 116 includes a pair of seal bars 116a, and heat sealing is performed by clamping the predetermined position with the pair of seal bars 116a for a predetermined time.

[0044] The seal bar 116a, in one example, has a shape in which ridges and grooves extending in the left-right direction of FIG. 1 are alternately arranged in the vertical direction. In this case, linear seal portions (portions indicated by dotted lines in FIG. 1) 4a and 5a are formed at the portions where the ridges are pressed.

[0045] <S4: Cutting process> Next, by further rotating the feed roll 114, the horizontal seal portion 11 is moved to the position of the press-cutter 118. The press-cutter 118 includes a pair of bars 118a.

[0046] Next, as shown in FIG. 7, the press-cutter 118 is closed to clamp and cool the horizontal seal portion 11, and the horizontal seal portion 11 is cut with a cutter blade (not shown) and vertically divided to form the upper horizontal seal portion of the downstream packaging bag 1 and the lower horizontal seal portion 5 of the upstream cylindrical body 3. When the horizontal seal portion 11 of the downstream packaging bag 1 is cut, it falls onto the conveyor 130.

[0047] <S5: Filling process> Next, as shown in FIG. 7, when the squeezing roll 115, which was in a closed state in the previous process, is opened, the content W that was introduced from the hopper 111 and accumulated on the upper side of the squeezing roll 115 in the previous process falls to the lower side of the squeezing roll 115. Since the lower horizontal seal portion 5 is formed on the cylindrical body 3, the fallen content W is filled into the cylindrical body 3. A pair of shutter members 123 are arranged around the cylindrical body 3. The shutter members 123 are configured to be movable in the horizontal and vertical directions.

[0048] The content W is further put into the cylindrical body 3. When the content W in the cylindrical body 3 reaches the position of the sensor 122, as shown in FIG. 8, by closing the squeezing roll 115, the content W is divided into an upper part and a lower part of the squeezing roll 115. The content in the lower part of the squeezing roll 115 is the content for one bag of the packaging bag 1. Also, by closing the squeezing roll 115, an adhering part 3a is formed on the cylindrical body 3, and a bag part 3b is formed, which is the part where the content is accommodated between the adhering part 3a and the lower horizontal sealing part 5.

[0049] <S6: Feeding process> Next, while keeping the squeezing roll 115 closed, by rotating the feeding roll 114, as shown in FIG. 8, the adhering part 3a is moved to the position of the shutter member 123.

[0050] <S7: Clamping process> Next, as shown in FIG. 9, the shutter member 123 is moved horizontally to clamp the adhering part 3a above the bag part 3b, and further, by moving the shutter member 123 vertically downward (refer to the arrow in FIG. 9), the bag part 3b can be given tension. Here, it is preferable to move the shutter member 123 below the horizontal sealing machine 116. By doing so, it becomes possible to perform horizontal sealing while maintaining the tension given to the bag part 3b.

[0051] After that, by performing the horizontal sealing process (S3) while keeping the shutter member 123 above the bag part 3b, a horizontal sealing part 11 can be formed while giving tension to the bag part 3b at a position (adhering part 3a) higher than the part (bag part 3b) filled with the content W, and the packaging bag 1 is formed.

[0052] Then, as shown in FIG. 7, the shutter member 123 is returned to its original position, and the subsequent cutting process (S4) is performed. As a result, as shown in FIG. 7, the packaging bag 1 falls onto the conveyor 130.

[0053] In this manner, by repeating the steps S3 to S7, it is possible to continuously produce packaging bags 1 filled with the contents W. Note that, in the production of the packaging bag 1 in this embodiment, no heat treatment step is performed.

[0054] As described above, in the bag making and filling method of the present embodiment, the above-mentioned clamping step is performed on the cylindrical body 3, thereby giving the necessary tension to the packaging bag 1.

[0055] 3. Other embodiments In the above embodiment, the shutter member 123 is moved vertically downward, but the present invention is not limited to this. For example, the cylinder body 3 may be tensioned by moving the cylinder body 3 vertically upward in a state where the shutter member 123 sandwiches the cylinder body 3. In this way, by changing the relative position in the vertical direction between the shutter member 123 sandwiching the cylinder body 3 and the cylinder body 3, it is possible to obtain the same effect as the above embodiment. EXAMPLES

[0056] 1. Manufacturing of packaging bags 1 <Example 1> Using the film 2 having the following configuration, a packaging bag 1 having the configuration shown in Figures 1 to 4 and the following dimensions was manufactured according to the bag making and filling method of the above embodiment. Flour paste was filled into the packaging bag 1. The S2 / S1 ratio of the film 2 was about 3.3.

[0057] Film 2 (3-layer laminate film consisting of a base layer, an adhesive layer, and a sealant layer) Base layer: Polyamide (Unitika Co., Ltd., Emblem NC-15, thickness 15 μm) Adhesive layer: Maleic anhydride modified polyethylene, thickness 5 μm Sealant layer: LLDPE (Skyfilm Co., HR543, thickness 50 μm)

[0058] ·Packaging bag 1 The length of the packaging bag 1 in the left-right direction: 200 mm Vertical length of packaging bag 1: 600 mm Length of the palm part 8 in the left-right direction: 20 mm Length of the vertical seal 7 in the left-right direction: 10 mm Length of opening start part (notch) in left and right direction: 15mm The vertical length from the inner edge 4b ​​of the upper horizontal seal 4 to the tear start point 6: 5 mm

[0059] <Comparative Example 1> Film 2 was produced in the same manner as in Example 1, except that an isotropic film with S2 / S1=1 was used instead of Film 2 in Example 1.

[0060] 2. Opening test In the packaging bags 1 of the examples and comparative examples, both sides of the tear initiation portion 6 were pinched with both hands and the distance between the hands was increased along the longitudinal direction of the vertical seal portion 7, causing the film 2 to start tearing from the tear initiation portion 6, and then the manner in which the film 2 was torn was compared.

[0061] In the packaging bag of Example 1, after the seam portion 8 was torn, the tear spread diagonally to both sides of the seam portion in the main body portion 9, and then the tear progressed in a direction approximately parallel to the longitudinal direction D1 of the vertical seal portion 7, until the main body portion 9 was torn all the way to the bottom end of the packaging bag 1, forming a wide opening (approximately 10 cm wide) along the longitudinal direction D1.

[0062] In the packaging bag of Comparative Example 1, after the seam portion 8 was torn, the film 2 was torn in the main body portion 9 so as to extend along the circumferential direction of the main body portion 9. As a result, a wide opening along the longitudinal direction D1 was not formed. [Explanation of symbols]

[0063] 1: Packaging bag 1a: One fate 2: Film 2a: One fate 2b: Other Relationships 3: Cylindrical body 3a: Contact area 3b: Bag part 4: Upper horizontal seal 4a: Linear seal part 4l: Left curved part 4r: Right curved part 5: Lower horizontal seal 5a: Linear seal part 5l: Left curved part 5r: Right curved part 6:Tear start part 7: Vertical seal part 8: Gassho part 8a: Unsealed part 8b: Edge 9: Main body 11: Horizontal seal section 12 :Dotted and dashed line 13 :Dash-dot line 14 :Dotted and dashed line 15: Middle area 100: Bag making and filling machine 111: Hopper 112:Forma 113: Vertical sealing machine 114: Feed roll 115: Roll 116: Horizontal sealing machine 116a: Seal bar 118: Press and cutter 118a: Bar 119: Sensor 120: Payout roll 121: Payout roll 122: Sensor 123: Shutter parts 130: Conveyor 131: Cutter D1: Longitudinal direction D2: Orthogonal direction F: Rolled raw material W: Contents

Claims

1. A packaging bag, The packaging bag includes a cylindrical body formed by forming a vertical seal portion on a film, an upper horizontal seal portion, a lower horizontal seal portion, and a tear initiation portion, the vertical seal portion is formed by bending the film into a cylindrical shape and welding the films together at a joint portion formed by overlapping an inner surface of one edge side and an inner surface of the other edge side of the film, The upper horizontal seal portion is provided to close the upper side of the cylindrical body, The lower horizontal seal portion is provided to close the lower side of the cylindrical body, The tear initiation portion is provided in the joint portion, The packaging bag is composed of the joint portion and a main body portion other than the joint portion, The film has a first tear strength S1, which is a tear strength in the longitudinal direction of the vertical seal portion, and a second tear strength S2, which is a tear strength in a direction perpendicular to the longitudinal direction, A packaging bag in which S2 / S1 is 1.5 to 10 (excluding those in which the film has been treated to make it easy to open in a direction intersecting the longitudinal direction at a position of the main body adjacent to the tear initiation portion).

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

3. The packaging bag according to claim 1 or 2, A packaging bag, in which the circularity of a cross section perpendicular to the longitudinal direction at the longitudinal center of the vertical seal portion when the packaging bag is filled with contents is 0.5 or more.

4. A packaging bag according to any one of claims 1 to 3, The packaging bag comprises a film having a base layer made of polyamide and having linear cuttability.

5. A method for opening a packaging bag, comprising: The packaging bag includes a cylindrical body formed by forming a vertical seal portion on a film, an upper horizontal seal portion, a lower horizontal seal portion, and a tear initiation portion, the vertical seal portion is formed by bending the film into a cylindrical shape and welding the films together at a joint portion formed by overlapping an inner surface of one edge side and an inner surface of the other edge side of the film, The upper horizontal seal portion is provided to close the upper side of the cylindrical body, The lower horizontal seal portion is provided to close the lower side of the cylindrical body, The tear initiation portion is provided in the joint portion, The packaging bag is composed of the joint portion and a main body portion other than the joint portion, The film has a first tear strength S1, which is a tear strength in the longitudinal direction of the vertical seal portion, and a second tear strength S2, which is a tear strength in a direction perpendicular to the longitudinal direction, S2 / S1 is 1.5 to 10, The method includes a step of starting tearing of the film from the tear initiation portion, tearing the joint portion, and then tearing the main body portion, The method for opening a packaging bag, wherein the tearing of the main body portion is performed such that the tearing progresses along the longitudinal direction with the tearing spreading diagonally to both sides of the joint portion.

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