JP7723264B2 - packaging bag - Google Patents

Description

The present invention relates to a packaging bag.

Patent Document 1 discloses a packaging bag with a notch in the horizontal seal.

Japanese Patent Application Laid-Open No. 2020-26304

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

In Patent Document 1, a notch is provided in the horizontal seal section on the top of the bag body, and this horizontal seal section is welded across the entire surface, creating a so-called solid seal. With solid seals, welding defects are likely to occur, particularly in filling methods such as form-fill-fill, where the contents tend to adhere to the inner surface of the film.

To solve this problem, it is possible 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 sealing bar is applied locally to the area where the linear seal is being 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 poor welding is less likely to occur.

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

The present invention was made in light of these circumstances, and aims to provide a packaging bag that can be opened more easily.

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, and 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, and 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 to intersect at least two of the plurality of linear seal portions, and the cross seal portion is arranged to overlap the notch or an extension of the notch.

The packaging bag of the present invention has a cross seal that overlaps with the notch or its extension. This means that the tear line from the notch does not cross the middle section, or the number of times the tear line from the notch crosses the middle section is reduced, improving openability compared to a bag without a cross seal.

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 plurality of 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 is as described above, 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.

FIG. 2 is a plan view of the packaging bag 1 when no contents are contained. FIG. 2 is an enlarged view of an area A in FIG. 1 . FIG. 1 is a perspective view of a packaging bag 1 with contents inside. FIG. 2 is a layer structure diagram of the film 2. FIG. 1 is a diagram illustrating the configuration of a bag making and filling machine 100. 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. 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. 7 shows the state in which the horizontal seal portion 11 is being clamped by the press/cutter 118. This shows the state after the press/cutter 118 and the ironing rolls 115 are opened from the state shown in FIG. 9 shows the state after the contents W are further added and the squeezing rolls 115 are closed. 10. The state after the sealed portion 3a has moved to the position of the horizontal sealing device 116 is shown in FIG.

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 independent invention.

1. Packaging bag 1
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, Fig. 1 shows the packaging bag 1 in an empty state. Examples of contents include viscous foods such as flour paste, jam, and bean paste.

In the following description, the top, bottom, left, and right of Figure 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. Additionally, the surface on the vertical seal portion 7 side is referred to as the front side, and the opposite side is referred to as the back side.

The length of the packaging bag 1 in the left-right direction is, for example, 140 to 240 mm, with 160 to 220 mm being preferable. This length can be, 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 [vertical length of packaging bag 1 / horizontal length of packaging bag 1] is, for example, 1.5 to 5, with 2 to 4 being preferable. This value can be, 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.

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. The vertical seal portion 7 is formed by heat-sealing.

The upper horizontal seal portion 4 and the lower horizontal seal portion 5 are provided to close the upper and lower sides of the cylindrical body 3, respectively. The horizontal seal portions 4, 5 are preferably formed along the upper and lower ends of the cylindrical body 3, respectively. 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.

Notch 6 is formed at the upper end of upper horizontal seal portion 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.

The upper horizontal seal section 4 has multiple linear seal sections 4a and cross seal sections 4b. Each linear seal section 4a extends so as to intersect (preferably perpendicular to) the vertical seal section 7. Each linear seal section 4a preferably extends parallel to the upper edge 1a of the packaging bag 1. The multiple linear seal sections 4a preferably extend parallel to each other.

The thickness T1 of the linear seal portion 4a (the length in the direction perpendicular to the longitudinal direction of the linear seal portion 4a) is, for example, 0.1 to 4 mm, and preferably 0.8 to 2 mm. Specific examples of thickness T1 include 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 fall within a range between any two of the values exemplified here. Note that in this specification, "thickness of the linear seal portion" refers to the average thickness of multiple linear seal portions 4a.

The number of linear seal portions 4a is, for example, 2 to 20, with 4 to 20 being preferred. Specific examples of this number include 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 numbers exemplified here, or any number greater than or equal to any of them.

The cross seal portion 4b is arranged to intersect (preferably perpendicular to) at least two of the multiple linear seal portions 4a. The number of linear seal portions 4a that the cross seal portion 4b intersects is, for example, 2 to 20, and preferably 4 to 20. Specific examples of this number include 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 numbers exemplified here or any number equal to or greater than any of them.

A middle section 4c is provided between two adjacent linear seal sections 4a. In the middle sections 4c, the films 2 are not welded together or are welded more weakly (with lower weld strength per unit width) than the linear seal sections 4a. The thickness S of the middle sections 4c (the length perpendicular to the longitudinal direction of the middle sections 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. Note that in this specification, "thickness of the middle section" refers to the average thickness of the multiple middle sections 4c.

The cross seal 4b is positioned so that it overlaps 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 the tear line from the notch 6 crosses the middle portion 4c, resistance is added to the tearing of 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 that it overlaps the notch 6 or its extension, so 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 package without the cross seal 4b.

The cross seal 4b is preferably provided over the entire vertical length of the upper horizontal seal 4, but may also be provided over only a portion of the upper horizontal seal 4. In the latter case, improved openability can be expected 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 it is preferable that H3/H ≥ 0.5. 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 greater than any two of the values listed here. The length H is, for example, 10 to 30 mm, specifically 10, 15, 20, 25, or 30 mm, and may be within or greater than any two of the values listed here.

Furthermore, it is preferable that the cross seal portion 4b be positioned so that it overlaps the inner edge 6c of the notch 6. Tearing from the notch 6 is most difficult immediately after tearing begins, so by positioning the cross seal portion 4b so that it overlaps the inner edge 6c of the notch 6, it is possible to improve the ease of opening immediately after tearing begins.

The width W of the cross seal portion 4b (the length of the cross seal portion 4b in the direction along the upper edge 1a of the packaging bag 1) is, for example, 0.6 to 20 mm, and 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. It is also preferable that W/T1 is 1.5 or greater. 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 greater than any two of the values exemplified here.

It is preferable that the cross seal portion 4b has a higher welding strength per unit width than the linear seal portion 4a in the outer region 4o. In this case, the tearability of the film 2 at the cross seal portion 4b is particularly good.

The upper horizontal seal section 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 section 4 than the outer region 4o. The inner region 4i has a higher welding strength per unit width than the outer region 4o. In this way, by increasing the welding strength of the inner region 4i, welding can be performed reliably and leakage of the contents can be prevented even when a thick layer of contents is attached to the inner surface of the film. The welding strength per unit width of the portions of the inner region 4i other than the cross seal section 4b may be the same as, or higher or lower than, the cross seal section 4b.

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

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. It is also preferable that S1/S≧1.1. To increase the welding strength of the inner region 4i, it is preferable to press the films 2 together firmly with a seal bar during welding. During this process, the amount of resin extruded from the pressed area 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 the welding. S1/S is, for example, 1.1 to 5, specifically 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 values exemplified here.

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

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 shrinks while filled with the contents, the portions of the packaging bag 1 away from the horizontal seals 4, 5 assume a roughly cylindrical shape, allowing it to be rolled for transport (hereinafter referred to as "rolling transport"). On the other hand, the portions of the packaging bag 1 closer to the horizontal seals 4, 5 are less likely to expand, resulting in a flattened shape that hinders rolling transport of the packaging bag 1. This tendency is particularly pronounced when the inner edges of the horizontal seals 4, 5 do not have curved portions that convex outward, or when curved portions are provided but are short in length in the left-right direction.

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 edges 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 and Wr, respectively, it is preferable that Wr/Ws and Wl/Ws are 0.1 to 0.4. By forming such curved portions, as shown in Figure 3, the packaging bag 1 can easily expand even near the horizontal seals 4, 5, resulting in a roughly cylindrical outer shape, which facilitates smooth rolling and transport 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, and 0.4, and may be within a range between any two of the values listed 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. Specific examples of Wl and Wr are 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mm, and may be within a range between any two of the values exemplified here.

Furthermore, the left curved portions 4l, 5l and the right curved portions 4r, 5r are preferably arc-shaped, and if the radii of curvature are Rl and Rr, then 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. Rl and Rr are, for example, 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.

Furthermore, because the horizontal seal section 4 has a notch 6, if excessive load is applied near the horizontal seal section 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 for the left curved section 4l and right curved section 4r of the horizontal seal section 4 to 0.1 to 0.4, respectively. On the other hand, the left curved section 5l and right curved section 5r of the horizontal seal section 5 are not required, and Wr/Ws and Wl/Ws for the left curved section 5l and right curved section 5r may be less than 0.1.

Furthermore, if the length of the notch 6 is L, then 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, with 4 to 8 mm being preferred. 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.

If the vertical length of the horizontal seal portion 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, 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, and 0.3, and may be within a range between any two of the values exemplified here.

When the horizontal seal section 4 is composed of multiple linear seal sections 4a, where N1 is the number of linear seal sections 4a containing notches 6 and N2 is the number of linear seal sections 4a where the extensions of the notches 6 intersect (i.e., the number of linear seal sections 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 given here.

If the vertical length of the lower horizontal seal section 5 on the extension line of the notch 6 is H1, then it is preferable that H>H1. Furthermore, if the vertical length of the portion of the upper horizontal seal section 4 where the notch 6 is not provided is H2 (=H-L), then it is preferable that H2>H1. H/H1 and H2/H1 are, for example, 1.1 to 3, and more specifically, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, or 3, and may be within a range between any two of the values exemplified here.

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

The packaging bag 1 preferably includes first and second notches 6a and 6b. The first notch 6a is positioned toward the left edge of the horizontal seal section 4, and the second notch 6b is positioned toward the right edge of the horizontal seal section 4. Furthermore, if the distance from the left edge of the horizontal seal section 4 to the first notch 6a is D1 and the distance from the right edge of the horizontal seal section 4 to the second notch 6b is D2, 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 sections 4l and 4r. If these values are too large, it may be difficult to remove the contents. Specific examples of this value are 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, and 2.5, and 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.

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 of the packaging bag 1 starting from the first notch 6a to open the left side of the bag, and tearing the film 2 on the front and back of the packaging bag 1 starting from the second notch 6b to open the right side of the bag. 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, and 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 shown here.

As shown in Figure 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.

The base layer 2a is arranged so that it is exposed on the outer surface of the packaging bag 1, and the sealant layer 2b is arranged so that it is 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.

The base layer 2a is made of a material with excellent strength and high impact resistance. Materials that can be used for the base layer 2a include heat-shrinkable polyamide, polyolefin, and polyethylene. The adhesive layer 2c is a layer that adheres the base layer 2a and the sealant layer 2b together, and can be made of, for example, polyethylene.

The polyamide of the base layer 2a preferably contains an aromatic polyamide. This is because the base layer 2a has linear cut properties in the machine direction and excellent barrier properties. There are no particular restrictions on the aromatic polyamide, but resins 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. However, 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 easily available industrially.

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. It is preferable that the film constituting the sealant layer 2b be one that can be cut in a straight line in the machine direction.

It is also preferable that at least one of the base layer 2a and the sealant layer 2b have linear cutting properties. In this case, the film 2 can be easily torn in a straight line starting from the notch 6. The thickness of the sealant layer 2b is preferably at least twice the thickness of the base layer 2a, and is preferably at least half the overall thickness of the film 2.

The film 2 can be formed by laminating a substrate layer 2a having a thickness of 10 μm to 20 μm, for example 15 μm, an adhesive layer 2c having a thickness of 10 μm to 30 μm, for example 20 μm, and a sealant layer 2b having a thickness of 30 μm to 50 μm, for example 40 μm. The film 2 typically has a thickness of 50 μm to 100 μm.

The base layer 2a and sealant layer 2b are laminated and bonded together by the adhesive layer 2c. For example, polyethylene can be used as the adhesive layer 2c, and the base layer 2a and sealant layer 2b can be bonded together using an extrusion lamination method. Alternatively, a material other than polyethylene can be used as the adhesive layer 2c, and the base layer 2a and sealant layer 2b can be bonded together using a dry lamination method. Alternatively, fusion bonding can be used without using the adhesive layer 2c. The film 2 formed from the base layer 2a, adhesive layer 2c, and sealant layer 2b in this way has high strength, impact resistance, airtightness, and other properties.

5 to 11, a bag-making and filling method using the film 2 will be described. This method can be carried out using a vertical bag-making and filling machine 100.

<S1: Film bending process>
First, film 2 unwound from roll F passes through multiple unwound rolls 120 and 121 and is guided to former 112. A sensor 119 is disposed midway along the path from roll F to former 112, and detects registration marks printed at regular intervals along the length of film 2, enabling a fixed length of film 2 to be sent out at regular time intervals onto the track of bag-making and sealing machine 100. As film 2 passes through former 112, it is curved into a cylindrical shape, with both side edges of the curved tip overlapping. An overlapping portion is formed in the overlapping portion.

A printing process may be provided in which printing is performed on the film 2 at a position before the former 112. This printing is preferably performed on the area that will become the front surface of the packaging bag 1 (the surface on the vertical seal 7 side). In this case, when the packaging bag 1 that has fallen onto the conveyor 130 in the cutting process described below is transported with the vertical seal 7 facing up, it is possible to check whether the printing has been performed properly.

<S2: Vertical sealing process>
Next, the overlapping portion of the film 2 is heat-sealed in a vertical sealing machine 113 to form a vertical seal portion 7. The vertical sealing machine 113 is equipped with a pair of seal rolls, and performs heat sealing while feeding out the film 2 by rotating the pair of seal rolls in opposite directions while holding the overlapping portion of the film 2 in synchronization with the movement of the film 2 at regular time intervals. By forming the vertical seal portion 7 in the film 2, the cylindrical body 3 is formed.

<S3: Horizontal sealing process>
Next, the feed roll 114 is rotated to move the cylindrical body 3 downstream by a predetermined length, and as shown in Figures 6 and 7, a predetermined position of the cylindrical body 3 is heat-sealed by a horizontal sealing machine 116 to form a horizontal seal section 11. The horizontal seal section 11 is configured by connecting the upper horizontal seal section 4 of the packaging bag 1 on the downstream side with the lower horizontal seal section 5 of the cylindrical body 3 on the upstream side, and is divided into upper and lower halves in the cutting process described below. The horizontal sealing machine 116 is equipped with a pair of seal bars 116a, and performs heat sealing by clamping the above-mentioned predetermined position with the pair of seal bars 116a for a predetermined period of time.

In one example, the seal bar 116a has a shape in which convex and concave stripes extending in the left-right direction of FIG. 1 are arranged alternately in the up-down direction. In this case, linear seal portions 4a, 5a are formed where the convex stripes are pressed. Furthermore, it is preferable that the protruding height of the convex stripes of the seal bar 116a at the portion corresponding to the inner region 4i be greater than that of the portion corresponding to the outer region 4o. This allows the seal bar 116a to be pressed particularly strongly against the cylindrical body 3 at the portion corresponding to the inner region 4i, thereby suppressing the occurrence of welding defects even when a thick layer of contents W is attached to the inner surface of the cylindrical body 3, and enabling the welding strength per unit width in the inner region 4i to be greater than that of the outer region. It is preferable that the protruding height of the cross seal portion 4b of the convex stripes of the seal bar 116a be greater than that of the portion corresponding to the linear seal portion 4a in the outer region 4o. As a result, the seal bar 116a is pressed particularly strongly against the cylindrical body 3 at the area corresponding to the cross seal 4b, reducing the thickness of the film 2 at the cross seal 4b and increasing the welding strength per unit width at the cross seal 4b, resulting in particularly high tearability.

<S4: Cutting process>
7, the feed roll 114 is rotated to move the horizontal sealing unit 11 to the position of the press/cutter 118. The press/cutter 118 includes a pair of bars 118a.

Next, as shown in FIG. 8, the press/cutter 118 is closed to clamp and cool the horizontal seal portion 11, and a cutter blade (not shown) is used to cut the horizontal seal portion 11 and divide it into an upper and lower portion, thereby forming an upper horizontal seal portion 4 of the downstream packaging bag 1 and a lower horizontal seal portion 5 of the upstream cylinder 3, as shown in FIG. 9. Once 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 dividing the horizontal seal portion 11 and forming the notch 6 simultaneously, the manufacturing process can be shortened.

Furthermore, the notch 6 is formed in the upper horizontal seal portion 4 of the downstream packaging bag 1, but not in the lower horizontal seal portion 5 of the upstream cylindrical body 3. As a result, even if an impact is applied to the lower horizontal seal portion 5 of the cylindrical body 3 when filling the contents W into the cylindrical body 3, the lower horizontal seal portion 5 will not tear. Furthermore, because the packaging bag 1 falls with the lower horizontal seal portion 5, which does not have a notch, facing downward, tearing of the upper horizontal seal portion 4 due to the impact of the fall is suppressed.

The cutter blade has a horizontal blade for dividing the horizontal seal portion 11 into upper and lower halves, and a vertical blade for forming the notch 6. The vertical blade is fixed to the horizontal blade. The vertical blade is more susceptible to damage than the horizontal blade, so it is replaceable. Furthermore, the longer the vertical blade, the more susceptible it is to damage, so shortening the notch 6 can reduce the frequency of vertical blade replacement.

<S5: Filling process>
Next, as shown in Figure 9, when the squeezing roll 115 is opened, the contents W that were poured from the hopper 111 in the previous process and that have accumulated above the squeezing roll 115 fall below the squeezing roll 115. Because the lower horizontal seal portion 5 is formed in the cylindrical body 3, the fallen contents W are filled into the cylindrical body 3. A forming device 123 is disposed around the cylindrical body 3, and the peripheral surface of the cylindrical body 3 abuts against the forming device 123 to define the outer shape of the cylindrical body 3.

Next, the contents W are further poured into the cylinder 3. When the contents W inside the cylinder 3 reach the position of the sensor 122, the squeezing roll 115 is closed as shown in Figure 10, dividing the contents W into an upper portion and a lower portion of the squeezing roll 115. The contents below the squeezing roll 115 constitute one bag's worth of packaging bag 1. Closing the squeezing roll 115 also forms a sealed portion 3a in the cylinder 3, and a bag portion 3b is formed between the sealed portion 3a and the lower horizontal seal portion 5. An upper horizontal seal portion 4 is formed above the bag portion 3b, thereby forming the packaging bag 1.

<S6: Feeding process>
Next, by rotating the feed roll 114 while keeping the squeezing roll 115 closed, the sealed portion 3a is moved to the position of the horizontal sealing machine 116, as shown in Fig. 11. Thereafter, the horizontal sealing step is carried out in the same manner as in S3, whereby the horizontal seal portion 11 can be formed at a position (the sealed portion 3a) higher than the portion (the bag portion 3b) where the contents W are filled.

After this, steps S3 to S6 can be repeated to continuously produce packaging bags 1 filled with contents W.

<Heat treatment process>
The packaging bag 1 on the conveyor 130 is transported to a heat treatment furnace, where it is heat-treated and shrinks to a roughly cylindrical shape. Thereafter, the packaging bag 1 is transported while being rolled. In this embodiment, curved portions 4r, 5r, 4l, and 5l are provided at both ends of the inner edge of the horizontal seals 4 and 5, so that the packaging bag 1 remains nearly cylindrical even near the horizontal seals 4 and 5, allowing the packaging bag 1 to be easily rolled. Furthermore, tearing of the film 2 starting from the notch 6 is less likely to occur during rolling transport.

Through the above process, a packaging bag 1 filled with contents W is produced. The packaging bag 1 can be opened by tearing the film 2 on the front and back of the packaging bag 1 starting from the notch 6.

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 may be the same as those in the upper horizontal seal section 4.

1: packaging bag 1a: upper edge 2: film 2a: base material layer 2b: sealant layer 2c: adhesive layer 3: cylindrical body 3a: sealed portion 3b: bag portion 4: upper horizontal seal portion 4a: linear seal portion 4b: cross seal portion 4c: middle portion 4d: inner edge 4e: middle portion 4i: inner region 4l: left curved portion 4o: outer region 4r: right curved portion 5: lower horizontal seal portion 5a: linear seal portion 5l: left curved portion 5r: right curved portion 6: notch 6a: first notch 6b: second notch 6c: inner edge 7: vertical seal portion 11: horizontal seal portion 100: bag form-fill machine 111: hopper 112: former 113: vertical seal machine 114: feed roll 115: roll 116: horizontal seal machine 116a : Seal bar 118 : Press/cutter 118a : Bar 119 : Sensor 120 : Feed roll 121 : Feed roll 122 : Sensor 123 : Forming device 130 : Conveyor F : Roll-shaped raw material W : Contents

Claims (4)

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 . 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. 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. The 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.