packaging bags

Abstract

To provide a packaging bag that can be more easily opened.SOLUTION: A packaging bag includes a tubular body which is configured by forming a longitudinal seal part on a film, an upper lateral seal part, a lower lateral seal part, and a notch. The upper lateral seal part is provided to close the upper side of the tubular part. The lower lateral seal part is provided to close the lower side of the tubular part. The notch is provided at the upper end of the upper lateral seal part. The upper lateral seal part includes a plurality of linear seal parts and intersecting seal parts. The plurality of linear seal parts extends to intersect the longitudinal seal part. The intersecting seal parts are provided to intersect at least two of the plurality of linear seal parts. The intersecting seal parts are provided to overlap the notches or extensions of the notches.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 notch is provided in the horizontal seal portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-26304 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the packaging bag can be opened and the contents can be removed by tearing the bag body from the notch without using a blade.

[0005] In Patent Document 1, a notch is provided in the horizontal seal provided on the upper side of the bag body, and this horizontal seal is welded all over, so-called solid seal. Solid seals are prone to poor welding, especially in filling methods such as form-fill-fill, where the contents tend to adhere to the inner surface of the film.

[0006] To solve this problem, it is conceivable to provide multiple parallel linear seals in the horizontal seal section. The linear seals are thin, linear seals. When forming the linear seals, the pressure of the seal bar is applied locally to the area where the linear seals are to be formed. This has the advantage that even if contents are attached to the inner surface of the film, the contents can be pushed aside, allowing for proper sealing, and reducing the risk of poor welding.

[0007] On the other hand, the film is more difficult to tear in the middle between adjacent linear seals than at the linear seals, so resistance is added to tearing the film each time the tear line from the notch reaches the middle, making it difficult to tear (i.e., difficult to open).

[0008] The present invention has been made in view of the above circumstances, and aims to provide a packaging bag that can be easily opened. [Means for solving the problem]

[0009] According to the present invention, there is provided a 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 notch, wherein 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 notch is arranged at the upper end of the upper horizontal seal portion, the upper horizontal seal portion comprises a plurality of linear seal portions and a cross seal portion, the plurality of linear seal portions extend so as to intersect the vertical seal portion, the cross seal portion is arranged so as to intersect at least two of the plurality of linear seal portions, and the cross seal portion is arranged so as to overlap the notch or overlap an extension of the notch.

[0010] In the packaging bag of the present invention, the cross seal is provided so as to overlap the notch or its extension line, so that the tear line from the notch does not cross the middle part, or the number of times that the tear line from the notch crosses the middle part is reduced, improving openability compared to a bag without the cross seal.

[0011] Various embodiments of the present invention will be described below as examples, and the embodiments shown below can be combined with each other. Preferably, the packaging bag is one described above, in which, where the vertical length of the upper horizontal seal portion at the location where the notch is provided is H and the length of the cross seal portion is H3, H3 / H≧0.5. Preferably, the packaging bag described above is one in which, when the thickness of the multiple linear seal portions is T1 and the length of the cross seal portion in the direction along the upper edge of the packaging bag is W, W / T1≧1.5. Preferably, the packaging bag described above has an inner region and an outer region, the inner region is positioned closer to the inner edge of the upper horizontal seal portion than the outer region, and the inner region has a higher welding strength per unit width than the outer region. Preferably, the packaging bag described above is one in which, when the thickness of the intermediate portion between two adjacent linear seal portions is S and the thickness of the intermediate portion between the inner region and the outer region is S1, S1 / S≧1.1. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a plan view of the packaging bag 1 when no contents are contained. [Figure 2] FIG. 2 is an enlarged view of an area A in FIG. [Figure 3] FIG. 1 is a perspective view of a packaging bag 1 with contents inside. [Figure 4] FIG. 2 is a layer structure diagram of film 2. [Figure 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 horizontal sealing machine 116 of a bag making and filling machine 100, showing a state in which a horizontal seal portion 11 is being formed by the horizontal sealing machine 116. FIG. [Figure 7] This shows the state after the horizontal sealing machine 116 has opened from the state shown in FIG. 6 and the horizontal sealing unit 11 has moved to the position of the press / cutter 118. [Figure 8] 7 shows the state in which the horizontal seal portion 11 is being clamped by the press / cutter 118. [Figure 9] This shows the state after the press / cutter 118 and the ironing rolls 115 are opened from the state shown in FIG. [Figure 10] This shows the state after the squeezing rolls 115 have closed after the contents W have been further added, following the state shown in FIG. [Figure 11] This shows the state after the adhesive portion 3a has moved from the state of FIG. 10 to the position of the horizontal sealing device 116. DETAILED DESCRIPTION OF THE INVENTION

[0013] The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an invention independently.

[0014] 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 cylindrical body 3 formed by forming a vertical seal 7 on a film 2, an upper horizontal seal 4, a lower horizontal seal 5, and a notch 6. The packaging bag 1 is normally filled with contents, but for convenience, Figure 1 shows the packaging bag 1 in an empty state. Examples of contents include viscous foods such as flour paste, jam, and bean paste.

[0015] 1 will be referred to as the top, bottom, left, and right of the packaging bag 1. Specifically, the axial direction of the cylindrical body 3 is the top and bottom direction, and the side on which the notch 6 is formed is the upper side. The left and right sides when the vertical seal portion 7 is positioned on the front side are the left and right sides of the packaging bag 1. The surface on the vertical seal portion 7 side is referred to as the front side, and the opposite surface is referred to as the back side.

[0016] The length of the packaging bag 1 in the left-right direction is, for example, 140 to 240 mm, preferably 160 to 220 mm. Specifically, this length is, for example, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, or 240 mm, and may be within a range between any two of the 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 filling difficult. This problem is more pronounced when the contents are highly viscous. The value of [length of packaging bag 1 in the up-down direction / length of packaging bag 1 in the left-right direction] is, for example, 1.5 to 5, and preferably 2 to 4. Specifically, this value is, for example, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5, and may be within a range between any two of the values exemplified here.

[0017] The cylindrical body 3 can be formed by bending the film 2 into a cylindrical shape and heat-sealing both ends of the film 2 in an overlapping state. A vertical seal portion 7 is formed by heat-sealing.

[0018] The upper horizontal seal portion 4 and the lower horizontal seal portion 5 are provided 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 intersect the vertical seal portion 7 at right angles. The horizontal seal portions 4, 5 can each be formed by heat-sealing the cylindrical body 3.

[0019] Notch 6 is formed at the upper end of upper horizontal seal 4. Notch 6 is a cut or notch, and by tearing film 2 starting from notch 6, packaging bag 1 can be opened and the contents can be removed. The number of notches 6 may be one or multiple. If notches 6 are provided in multiple locations, packaging bag 1 can be opened at multiple locations, allowing the contents to be removed smoothly.

[0020] The upper horizontal seal portion 4 has multiple linear seal portions 4a and cross seal portions 4b. Each linear seal portion 4a extends so as to intersect (preferably perpendicular to) the vertical seal portion 7. Each linear seal portion 4a preferably extends parallel to the upper edge 1a of the packaging bag 1. The multiple linear seal portions 4a preferably extend parallel to one another.

[0021] The thickness T1 of the linear seal portion 4a (the length of the linear seal portion 4a in the direction perpendicular to the longitudinal direction) is, for example, 0.1 to 4 mm, and preferably 0.8 to 2 mm. Specific examples of the thickness T1 are 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 mm, and may be within a range between any two of the values exemplified here. In this specification, the "thickness of the linear seal portion" refers to the average value of the thicknesses of multiple linear seal portions 4a.

[0022] The number of linear seal portions 4a is, for example, 2 to 20, and preferably 4 to 20. Specifically, this number is, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, and may be within a range between any two of the numerical values exemplified here or equal to or greater than any one of them.

[0023] The cross seals 4b are provided so as to intersect (preferably perpendicular to) at least two of the multiple linear seals 4a. The number of linear seals 4a that the cross seals 4b intersect with is, for example, 2 to 20, and preferably 4 to 20. Specific examples of this number are 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20, and may be within a range between any two of the numerical values exemplified here or equal to or greater than any one of them.

[0024] An intermediate portion 4c is provided between two adjacent linear seals 4a. In the intermediate portion 4c, the films 2 are not welded together or are welded more weakly (i.e., the weld strength per unit width is lower) than the linear seals 4a. The thickness S of the intermediate portion 4c (the length perpendicular to the longitudinal direction of the intermediate portion 4c) is, for example, 0.4 to 4 mm, preferably 0.8 to 2 mm. Specific examples of the thickness S are 0.4, 0.6, 0.8, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 mm, and may be within a range between any two of the values exemplified here. In this specification, the "thickness of the intermediate portion" refers to the average thickness of the multiple intermediate portions 4c.

[0025] The cross seal 4b is positioned so as to overlap the notch 6 or an extension of the notch 6. The film 2 is more difficult to tear at the middle portion 4c than at the linear seal 4a. Therefore, if a tear line from the notch 6 crosses the middle portion 4c, resistance is added to tearing the film 2 each time the tear line crosses the middle portion 4c, making it difficult to tear. On the other hand, in this embodiment, the cross seal 4b is positioned so as to overlap the notch 6 or an extension thereof, so that the tear line from the notch 6 does not cross the middle portion 4c or the number of times the tear line from the notch 6 crosses the middle portion 4c is reduced, improving openability compared to a case where the cross seal 4b is not present.

[0026] The cross seal 4b preferably extends over the entire vertical length of the upper horizontal seal 4, but may also extend over only a portion of the upper horizontal seal 4. In the latter case, the openability can be improved depending on the extent of the cross seal 4b. If the vertical length of the upper horizontal seal 4 at the location of the notch 6 is H and the length of the cross seal 4b is H3, then H3 / H ≥ 0.5 is preferred. In other words, the cross seal 4b is preferably provided over at least half of the height of the upper horizontal seal 4. Specifically, H3 / H is, for example, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0, and may be within or equal to any two of the values exemplified here. The length H is, for example, 10 to 30 mm, specifically, 10, 15, 20, 25, or 30 mm, and may be within or equal to any two of the values exemplified here.

[0027] Additionally, it is preferable that the cross seal 4b be provided so as to overlap the inner edge 6c of the notch 6. Tearing from the notch 6 is most difficult immediately after the tearing begins, so by providing the cross seal 4b so as to overlap the inner edge 6c of the notch 6, it is possible to improve the ease of opening the package immediately after the tearing begins.

[0028] The width W of the cross seal 4b (the length of the cross seal 4b in the direction along the upper edge 1a of the packaging bag 1) is, for example, 0.6 to 20 mm, preferably 1 to 10 mm. Specifically, the width W is, for example, 0.6, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 mm, and may be within a range between any two of the values exemplified here. Furthermore, it is preferable that W / T1 ≧ 1.5. This value is, for example, 1.5 to 20, and specifically, for example, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 mm, and may be within a range between any two of the values exemplified here or equal to or greater than any two of the values exemplified here.

[0029] The cross seals 4b preferably have a higher welding strength per unit width than the linear seals 4a in the outer region 4o, which results in particularly good tearability of the film 2 at the cross seals 4b.

[0030] The upper horizontal seal 4 preferably comprises an inner region 4i and an outer region 4o. The inner region 4i is positioned closer to the inner edge 4d of the upper horizontal seal 4 than the outer region 4o. The inner region 4i has a higher welding strength per unit width than the outer region 4o. By increasing the welding strength of the inner region 4i in this way, even when a thick layer of content adheres to the inner surface of the film, welding can be performed reliably and leakage of the content can be prevented. The welding strength per unit width of the portions of the inner region 4i other than the cross seal 4b may be the same as, or higher or lower than, the cross seal 4b.

[0031] The number of linear seals 4a provided in the inner region 4i is two in Fig. 2, but it may be one or three or more. This number is, for example, 1 to 10, specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, and may be within a range between any two of the numerical values exemplified here or any number greater than or equal to the number. The thickness of the linear seals 4a in the inner region 4i may be the same as, or thinner or thicker than, the thickness of the linear seals 4a in the outer region 4o.

[0032] The thickness S1 of the intermediate portion 4e between the inner region 4i and the outer region 4o is, for example, 0.5 to 10 mm, preferably 1 to 5 mm. Specifically, the thickness S1 may be, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm, and may be within a range between any two of the values exemplified here. Furthermore, it is preferable that S1 / S≧1.1. To increase the welding strength of the inner region 4i, it is preferable to strongly press the films 2 together with a seal bar during welding. At this time, the amount of resin extruded from the pressed portion is greater than that of the outer region 4o. Therefore, by increasing the thickness of the intermediate portion 4e, the extruded resin is accommodated, improving the stability of welding. S1 / S is, for example, 1.1 to 5, specifically, for example, 1.1, 1.3, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, and may be within a range between any two of the numerical values exemplified here.

[0033] The lower horizontal seal portion 5 preferably has a plurality of linear seal portions 5a. The description of the linear seal portions 5a is the same as that of the linear seal portions 4a.

[0034] The film 2 is preferably a heat-shrinkable film. In this case, the packaging bag 1 can be shrunk by subjecting it to a heat treatment while it is filled with the contents. When the packaging bag 1 is shrunk while filled with the contents, the packaging bag 1 assumes a roughly cylindrical shape in the areas of the packaging bag 1 away from the horizontal seals 4 and 5, allowing it to be rolled for transportation (hereinafter referred to as "rolling transportation"). On the other hand, the packaging bag 1 does not expand easily in areas of the packaging bag 1 closer to the horizontal seals 4 and 5, so the packaging bag 1 assumes a flat shape, hindering the rolling transportation of the packaging bag 1. This tendency is particularly pronounced when there are no curved portions that convex outward at both ends of the inner edge of the horizontal seals 4 and 5, or when there are curved portions but the length in the left-right direction is short.

[0035] Therefore, it is preferable to provide left curved portions 4l, 5l and right curved portions 4r, 5r that convex outward at both ends of the inner edge of the horizontal seals 4, 5. Furthermore, if the horizontal length of the horizontal seals 4, 5 is Ws and the horizontal lengths of the left curved portions 4l, 5l and right curved portions 4r, 5r are Wl, Wr, respectively, then Wr / Ws and Wl / Ws are preferably 0.1 to 0.4. By forming such curved portions, as shown in FIG. 3, the packaging bag 1 can easily expand even in the vicinity of the horizontal seals 4, 5, resulting in a roughly cylindrical outer shape, which allows for smooth rolling and conveyance of the packaging bag 1. While Wr and Wl are preferably the same, they may be different. Specifically, Wr / Ws and Wl / Ws are, for example, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, or 0.4, and may be within a range between any two of the 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.

[0036] Furthermore, the left curved portions 4l, 5l and the right curved portions 4r, 5r are preferably arc-shaped, and when the radii of curvature are Rl and Rr, Rl / Ws and Rr / Ws are preferably 0.1 to 0.4, respectively. Specific examples of Rl / Ws and Rr / Ws are 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 values exemplified here. Specific examples of Rl and Rr are 20 to 60 mm, and preferably 30 to 50 mm. Specific examples of Rl and Rr are 20, 25, 30, 35, 40, 45, 50, 55, and 60 mm, and may be within a range between any two of the values exemplified here.

[0037] Furthermore, because the horizontal seal 4 has a notch 6, if excessive load is applied to the vicinity of the horizontal seal 4 during rolling transport, tearing is likely to occur starting from the notch 6. Therefore, it is particularly preferable to set Wr / Ws and Wl / Ws to 0.1 to 0.4 for the left curved portion 4l and the right curved portion 4r of the horizontal seal 4. On the other hand, the left curved portion 5l and the right curved portion 5r of the horizontal seal 5 are not essential, and the Wr / Ws and Wl / Ws for the left curved portion 5l and the right curved portion 5r may be less than 0.1.

[0038] Furthermore, assuming that the length of the notch 6 is L, L / Wl and L / Wr are preferably each 0.01 to 0.5. If this value is too small, tearing of the film 2 starting from the notch 6 may be difficult, while if this value is too large, tearing starting from the notch 6 may progress during rolling transport. Specific examples of this value are 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, and 0.5, and may be within a range between any two of the values exemplified here. L is, for example, 3 to 10 mm, and preferably 4 to 8 mm. Specific examples of L are 3, 4, 5, 6, 7, 8, 9, and 10 mm, and may be within a range between any two of the values exemplified here.

[0039] If the vertical length of the horizontal seal 4 at the location where the notch 6 is provided is H, then L / H is preferably 0.01 to 0.3, and more preferably 0.05 to 0.2. If this value is too small, it may be difficult to tear the film 2 starting from the notch 6, whereas if this value is too large, tearing starting from the notch 6 may progress during rolling transport. Specific examples of this value are 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, and 0.3, and may be within a range between any two of the values exemplified here.

[0040] When the horizontal seal 4 is composed of multiple linear seals 4a, where N1 is the number of linear seals 4a containing notches 6 and N2 is the number of linear seals 4a where the extensions of the notches 6 intersect (i.e., the number of linear seals 4a without notches 6), it is preferable that N2 > N1. N2 / N1 is, for example, 1.5 to 10, specifically 1.5, 2, 3, 4, 5, 6, 7, 8, 9, or 10, and may be within a range between any two of the values exemplified here.

[0041] If the vertical length of the bottom horizontal seal 5 on the extension of the notch 6 is H1, then it is preferable that H>H1. Furthermore, if the vertical length of the portion of the top horizontal seal 4 where the notch 6 is not provided is H2 (=HL), then it is preferable that H2>H1. H / H1 and H2 / H1 are, for example, 1.1 to 3, and specific examples are 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, and 3, and may be within a range between any two of the values exemplified here.

[0042] It is preferable that the notch 6 is positioned so that the extension line of the notch 6 does not intersect with the curved portions 4l, 4r. If the extension line of the notch 6 intersects with the curved portions 4l, 4r, the tear line may be bent at the curved portions 4l, 4r when the film 2 is torn starting from the notch 6.

[0043] The packaging bag 1 preferably includes first and second notches 6a and 6b as the notches 6. The first notch 6a is positioned toward the left end of the horizontal seal 4, and the second notch 6b is positioned toward the right end of the horizontal seal 4. If the distance from the left end of the horizontal seal 4 to the first notch 6a is D1 and the distance from the right end of the horizontal seal 4 to the second notch 6b is D2, then it is preferable that D1 / Wl and D2 / Wr are each 1.0 to 2.5. If these values are too small, the extensions of the notches 6a and 6b will intersect with the curved portions 4l and 4r. If these values are too large, it may be difficult to remove the contents. Specifically, this value may be, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, or 2.5, or may be within a range between any two of the values exemplified here. Note that one of the notches 6a and 6b may be omitted. In this case, it is sufficient that D1 / Wl or D2 / Wr is within the above range.

[0044] If the distance between the first and second notches 6a, 6b is D3, then D3 / Ws is preferably 0.35 or greater. The packaging bag 1 of this embodiment is designed to allow contents to be removed by tearing the film 2 on the front and back sides of the packaging bag 1 starting from the first notch 6a to open the left side of the packaging bag 1, and tearing the film 2 on the front and back sides of the packaging bag 1 starting from the second notch 6b to open the right side of the packaging bag 1. If D3 / Ws is too small, when the film 2 is torn starting from the notches 6a, 6b, too much of the contents may spill out of the packaging bag 1, making it difficult to handle. D3 / Ws is, for example, 0.35 to 0.6, specifically, for example, 0.35, 0.4, 0.45, 0.5, 0.55, or 0.6, and may be within a range between any two of the values exemplified here.

[0045] As shown in FIG. 4, the film 2 is preferably a laminated film having a base layer 2a and a sealant layer 2b, and more preferably has an adhesive layer 2c between the base layer 2a and the sealant layer 2b.

[0046] The base material layer 2a is arranged so as to be exposed on the outer surface of the packaging bag 1, and the sealant layer 2b is arranged so as to be exposed on the inner surface of the packaging bag 1. The sealant layers 2b are heat-sealed together to form the vertical seal portion 7 and the horizontal seal portions 4 and 5.

[0047] The base layer 2a is made of a material having excellent strength and high impact resistance. For example, heat-shrinkable polyamide, polyolefin, polyethylene, etc. is used as the base layer 2a. The adhesive layer 2c is a layer for bonding the base layer 2a and the sealant layer 2b so that they are laminated together, and for example, polyethylene, etc. is used as the adhesive layer 2c.

[0048] The polyamide of the base layer 2a preferably contains an aromatic polyamide, because in this case the base layer 2a has linear cutting properties in the MD direction and excellent barrier properties. The aromatic polyamide is not particularly limited, but a resin containing 70 mol % or more of polyamide structural units composed of xylylenediamine and an 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, but polymetaxylylene adipamide (hereinafter referred to as "MXD6") is preferred because it has excellent basic properties such as strength and gas barrier properties, and is relatively easy to obtain industrially.

[0049] The sealant layer 2b can be formed from a resin with excellent heat-sealing properties. For example, the sealant layer 2b can be formed from linear low-density polyethylene. The film constituting the sealant layer 2b is preferably one that has linear cutability in the MD direction.

[0050] Also, it is preferable that at least one of the base material layer 2a and the sealant layer 2b has linear cutability. This is because when the film 2 is torn starting from the notch 6, it is easily torn straight. The thickness of the sealant layer 2b is preferably at least twice the thickness of the base material layer 2a and preferably at least half the thickness of the entire film 2.

[0051] The film 2 can be formed by laminating a base material layer 2a with a thickness of 10 μm to 20 μm, for example 15 μm, an adhesive layer 2c with a thickness of 10 μm to 30 μm, for example 20 μm, and a sealant layer 2b with a thickness of 30 μm to 50 μm, for example 40 μm. As the film 2, it usually has a thickness of 50 μm to 100 μm.

[0052] Also, the base material layer 2a and the sealant layer 2b are adhered to each other so as to be laminated by the adhesive layer 2c. For example, polyethylene can be used as the adhesive layer 2c, and the base material layer 2a and the sealant layer 2b can be adhered to each other using the extrusion lamination method. Also, a material other than polyethylene can be used as the adhesive layer 2c, and the base material layer 2a and the sealant layer 2b can be adhered to each other using the dry lamination method. Alternatively, fusion without using the adhesive layer 2c can also be utilized. In this way, the film 2 formed from the base material layer 2a, the adhesive layer 2c, and the sealant layer 2b has high strength, impact resistance, airtightness, gas barrier properties, etc.

[0053] 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 11. This method can be implemented using a vertical bag-making and filling machine 100.

[0054] <S1: Film bending process> First, the film 2 unwound from the roll stock F is guided to the former 112 through a plurality of unwinding rolls 120 and 121. A sensor 119 is arranged in the path from the roll stock F to the former 112, which detects the registration marks printed at regular intervals in the length direction of 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 both side edges of the curved tip overlap each other. An overlapping portion is formed at the overlapping part.

[0055] Incidentally, 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 becomes the front surface (the surface on the side of the longitudinal seal portion 7) of the packaging bag 1. In this case, when the packaging bag 1 dropped onto the conveyor 130 in the cutting process described later is conveyed with the longitudinal seal portion 7 on the upper side, it is possible to confirm whether the printing is properly performed.

[0056] <S2: Longitudinal sealing process> Next, the overlapping portion of the film 2 is heat-sealed by the longitudinal sealer 113 to form the longitudinal seal portion 7. The longitudinal sealer 113 includes a pair of seal rolls, and in accordance with the timing when the film 2 moves at regular time intervals, while sandwiching the overlapping portion 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 sending out the film 2. By forming the longitudinal seal portion 7 on the film 2, the cylindrical body 3 is formed.

[0057] <S3: Transverse sealing process> Next, by rotating the feed roll 114, the cylindrical body 3 is moved downstream by a predetermined length. As shown in FIGS. 6 to 7, 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 divided vertically in the cutting process described later. The horizontal sealing machine 116 includes a pair of seal bars 116a, and heat-sealing is performed by sandwiching the predetermined position with the pair of seal bars 116a for a predetermined time.

[0058] The seal bar 116a has, for example, 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 4a and 5a are formed at the portions where the ridges are pressed. Among the ridges of the seal bar 116a, it is preferable that the portion corresponding to the inner region 4i has a higher protrusion height than the portion corresponding to the outer region 4o. Thereby, since the seal bar 116a is pressed particularly strongly against the cylindrical body 3 at the portion corresponding to the inner region 4i, even when the content W adheres thickly to the inner surface of the cylindrical body 3, the occurrence of poor welding is suppressed, and the welding strength per unit width in the inner region 4i can be made higher than that in the outer region. Among the ridges of the seal bar 116a, it is preferable that the intersecting seal portion 4b has a higher protrusion height than the portion corresponding to the linear seal portion 4a in the outer region 4o. Thereby, since the seal bar 116a is pressed particularly strongly against the cylindrical body 3 at the portion corresponding to the intersecting seal portion 4b, the thickness of the film 2 at the intersecting seal portion 4b becomes thinner and the welding strength per unit width at the intersecting seal portion 4b becomes higher, so that the tearability becomes particularly high.

[0059] <S4: Cutting process> Next, as shown in FIG. 7, by 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.

[0060] Next, as shown in FIG. 8, the press-cutter 118 is closed to sandwich and cool the horizontal seal portion 11, and the horizontal seal portion 11 is cut by a cutter blade (not shown) and divided vertically. Thus, as shown in FIG. 9, 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 are formed. When the horizontal seal portion 11 of the downstream packaging bag 1 is cut, it falls onto the conveyor 130. When dividing the horizontal seal portion 11, a notch 6 may be formed in the upper horizontal seal portion 4. By simultaneously dividing the horizontal seal portion 11 and forming the notch 6, the manufacturing process can be shortened.

[0061] Also, the notch 6 is formed in the upper horizontal seal portion 4 of the downstream packaging bag 1 and not in the lower horizontal seal portion 5 of the upstream cylindrical body 3. Therefore, even if an impact is applied to the lower horizontal seal portion 5 when filling the content W into the cylindrical body 3, the lower horizontal seal portion 5 will not be torn. Further, since the packaging bag 1 falls with the lower horizontal seal portion 5 without a notch facing downward, the upper horizontal seal portion 4 is prevented from being torn by the impact of the fall.

[0062] The cutter blade has a horizontal blade for dividing the horizontal seal portion 11 vertically and a vertical blade for forming the notch 6. The vertical blade is fixed to the horizontal blade. Since the vertical blade is more prone to wear than the horizontal blade, it is replaceable. Also, since the longer the vertical blade, the more prone it is to wear, the replacement frequency of the vertical blade can be reduced by making the notch 6 shorter.

[0063] <S5: Filling Process> Next, as shown in FIG. 9, when the squeezing roll 115 is opened, the content W that was introduced from the hopper 111 in the previous process and accumulated above the squeezing roll 115 falls to the lower side of the squeezing roll 115. Since the lower horizontal seal portion 5 is formed in the cylindrical body 3, the fallen content W is filled into the cylindrical body 3. A forming device 123 is arranged around the cylindrical body 3 such that the outer surface of the cylindrical body 3 is defined by contacting the peripheral surface of the cylindrical body 3 with the forming device 123.

[0064] Next, 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. 10, the squeezing roll 115 is closed, and 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 adhesion part 3a is formed on the cylindrical body 3, and a bag part 3b is formed between the adhesion part 3a and the lower horizontal seal part 5. When the upper horizontal seal part 4 is formed above the bag part 3b, the packaging bag 1 is formed.

[0065] <S6: Feeding Process> Next, while keeping the squeezing roll 115 closed, the feeding roll 114 is rotated to move the adhesion part 3a to the position of the horizontal sealing machine 116 as shown in FIG. 11. After that, by performing the horizontal sealing process in the same manner as in S3, a horizontal seal part 11 can be formed at a position (adhesion part 3a) higher than the part (bag part 3b) filled with the content W.

[0066] After this, by repeating the steps of S3 to S6, the packaging bag 1 filled with the content W can be continuously manufactured.

[0067] <Heat Treatment Process> The packaging bag 1 on the conveyor 130 is conveyed to the heat treatment furnace and heat-treated in the heat treatment furnace to shrink and become substantially cylindrical. After that, the packaging bag 1 is conveyed while rolling. In this embodiment, since the curved parts 4r, 5r, 4l, 5l are provided at both ends of the inner edges of the horizontal seal parts 4, 5, the packaging bag 1 also becomes closer to a cylindrical shape near the horizontal seal parts 4, 5, and the packaging bag 1 can be easily rolled. Also, when being conveyed while rolling, the film 2 is less likely to be torn starting from the notch 6.

[0068] Through the above steps, the packaging bag 1 filled with the content W is manufactured. The packaging bag 1 can be opened by tearing the films 2 on the front and back of the packaging bag 1 starting from the notch 6.

[0069] 3. Other Configurations In the above embodiment, the notch 6 is provided only in the upper horizontal seal section 4, but one or more notches may also be provided in the lower horizontal seal section 5. The position and length of the notch in the lower horizontal seal section 5 can be the same as those in the upper horizontal seal section 4. [Explanation of symbols]

[0070] 1: Packaging bag 1a: upper edge 2: Film 2a: Base material layer 2b: sealant layer 2c: Adhesive layer 3: Cylindrical body 3a: Adhesion part 3b: Bag part 4: Upper horizontal seal 4a: Linear seal part 4b: Cross seal part 4c: Middle part 4d: Inner edge 4e: Middle section 4i :Inner area 4l: Left curved part 4o :Outer area 4r: Right curved part 5: Lower horizontal seal 5a: Linear seal part 5l: Left curved part 5r: Right curved part 6: Notch 6a: 1st notch 6b: Second notch 6c: Inner edge 7: Vertical seal 11: Horizontal seal section 100: Bag making and filling machine 111: Hopper 112:Former 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: Feed roll 121: Feed roll 122: Sensor 123: Molding equipment 130: Conveyor 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 in a film, an upper horizontal seal portion, a lower horizontal seal portion, and a notch, 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 notch is provided at an upper end of the upper horizontal seal portion, The upper horizontal seal portion includes a plurality of linear seal portions and a cross seal portion, The plurality of linear seal portions extend so as to intersect with the vertical seal portion, the cross seal portion is provided so as to cross at least two of the plurality of linear seal portions, The cross seal portion is provided so as to overlap the notch or an extension line of the notch, The upper horizontal seal portion has an inner region and an outer region, the inner region is positioned closer to the inner edge of the upper horizontal seal portion than the outer region, The inner region has a higher welding strength per unit width than the outer region, A packaging bag in which S1 / S≧1.1 is satisfied, where S is the thickness of the intermediate portion between two adjacent linear seal portions and S1 is the thickness of the intermediate portion between the inner region and the outer region.

2. The packaging bag according to claim 1, A packaging bag in which, where the notch is provided, the vertical length of the upper horizontal seal portion is H and the length of the cross seal portion is H3, H3 / H≧0.

5.

3. The packaging bag according to claim 1 or claim 2, A packaging bag in which W / T1≧1.5, where T1 is the thickness of the plurality of linear seal portions and W is the length of the cross seal portion in the direction along the upper edge of the packaging bag.

4. A packaging bag according to claim 3, The packaging bag has a left curved portion and a right curved portion that are convex outward at both ends of the inner edge of the upper horizontal seal portion.

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