bottom patch pocket

Abstract

To provide a one-side bottom glued bag sufficiently easily and automatically manufacturable without reducing manufacturing efficiency from mechanical equipment without requiring labor, although a hexagon bottom folded when being filled with a content from an opening end edge is smoothly expanded, even when an outer bag is formed from a material exhibiting relatively large rigidity.SOLUTION: A one-side bottom glued bag comprises a cylinder-shaped outer bag and a cylinder-shaped inner bag that is formed from a synthetic resin film, and has a closed bottom end. A bottom end part of the outer bag is folded along a first folding line in parallel with a bottom end edge. A triangle folding part is formed on both sides in a width direction by being opened with the first folding line as a center. A bottom end edge side is folded inward, overlapped, and bonded along a pair of second folding lines located on both sides of the first folding line in a longitudinal direction and in parallel with the first folding line to set on a hexagon bottom. The inner bag is longer in length than the outer bag. A Z-shaped folded-back part is formed in the inner bag, between the first folding line and an opening end edge.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a single-bottomed bag comprising a tubular outer bag and a tubular inner bag formed from a synthetic resin film and having a closed bottom end, the bottom end of the outer bag being set to a hexagonal bottom. [Background technology]

[0002] As is well known to those skilled in the art, single-bottom bags are commonly used as packaging bags for pharmaceuticals and chemical products, which require moisture resistance in particular. These bags include a tubular outer bag made of a single layer or multiple layers of paper selected from suitable papers such as kraft paper, polylaminated paper, and cross-kraft paper, and an inner bag made of a synthetic resin film with a closed bottom edge. The bottom edge of the outer bag is folded along a first fold line parallel to the bottom edge, and the bag is opened about the first fold line to form triangular folds on both sides in the width direction. The bottom edge is folded inward along a pair of second fold lines located on both sides of the first fold line in the longitudinal direction and parallel to the first fold line, and the two sides are overlapped and sealed to form a hexagonal bottom. In such single-bottom bags, contents are filled through the open opening edge, and it is important that the folded hexagonal bottom be expanded by the filled contents. However, in conventional single-bottom bags, the folded hexagonal bottom could not be smoothly unfolded, making it impossible to fill the bag with the specified amount of contents, and the contents would sometimes spill out from the opening edge of the bag.

[0003] Patent Document 1 listed below discloses a single-bottomed bag in which the bottom end of the inner bag is folded into a U-shape along a first fold line, and then further folded into a U-shape along one of a pair of second fold lines, and the outer surface of the inner bag is bonded to the inner surface of the outer bag at a position midway between the opening edge and the first fold line, and the outer surface of the inner bag is bonded to the inner surface of the outer bag at a position adjacent to the first fold line on the opening edge side. Patent Document 2 listed below also discloses a single-bottomed bag in which the bottom end of the inner bag is folded back and inserted into the inner bag in order to solve the above-mentioned problems of conventional single-bottomed bags. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-227792 [Patent Document 2] Patent No. 4588739 Summary of the Invention [Problem to be solved by the invention]

[0005] However, according to the experience of the present inventors, it has been found that the single-bottom bag disclosed in Patent Document 1 has a problem in that the fold along the first fold line does not release, preventing the contents from flowing downward at the first fold line, particularly when the outer bag is made of a relatively rigid material such as polylaminated paper or cross-kraft paper. Furthermore, the single-bottom bag disclosed in Patent Document 2 requires, in addition to the conventional process, a process of folding back and inserting the bottom end of the inner bag into the inner bag, which significantly reduces production efficiency even when performed manually or automatically by machine.

[0006] The present invention has been made in light of the above-mentioned circumstances, and its main technical object is to provide a new and improved single-bottomed bag that can be produced easily and automatically by machinery without requiring human labor and without reducing production efficiency, even when the outer bag is made of a relatively rigid material, and in which the folded hexagonal bottom smoothly unfolds when the contents are filled from the opening edge. [Means for solving the problem]

[0007] After careful study and experimentation, the inventors discovered that the above-mentioned main technical objective can be achieved by making the length of the inner bag longer than the length of the outer bag and forming a Z-shaped fold portion in the inner bag between the first fold line and the opening edge.

[0008] That is, according to the present invention, a single bottom seal bag that achieves the above-mentioned main technical object is as follows: A single-bottom sealed bag comprising a cylindrical outer bag and a cylindrical inner bag made of a synthetic resin film and closed at its bottom end, the bottom end of the outer bag being folded along a first fold line parallel to the bottom edge, the outer bag being opened about the first fold line to form triangular folded portions on both sides in the width direction, the bottom edge being folded inward along a pair of second fold lines located on both sides of the first fold line in the longitudinal direction and parallel to the first fold line, and overlapping and affixed to form a hexagonal bottom, the bottom end of the inner bag being folded into a U shape along the first fold line and further folded into a U shape along one of the pair of second fold lines, The length of the inner bag is greater than the length of the outer bag, and a Z-shaped folded portion is formed in the inner bag between the first fold line and the opening edge. hand , The longitudinal length L1 of the Z-shaped folded portion of the inner bag is 20 to 160 mm and is 0.5 times or less the longitudinal length L2 of the hexagonal bottom. The present invention provides a single-bottomed bag characterized by the above.

[0009] The term "longitudinal direction" used in the claims and specification of this patent refers to the direction from the opening edge of the bag toward the bottom edge (the vertical direction in Figures 1 and 2), and the term "width direction" refers to the direction extending along the bag perpendicular to the longitudinal direction (the horizontal direction in Figure 1).

[0010] Applicable At the bottom end, the outer surface of the portion of the inner bag folded along one of the second fold lines facing the inner surface of the outer bag is preferably bonded to the joint of the outer bag.At the open end, the outer surface of the inner bag is preferably bonded to the inner surface of the outer bag. [Effects of the Invention]

[0011] In a single-bottomed bag constructed according to the present invention, the length of the inner bag is longer than that of the outer bag, and a Z-shaped fold is formed in the inner bag between the first fold line and the opening edge. Therefore, the contents smoothly move one side of the inner bag over the first fold line to one side (lower side) of the hexagonal bottom as the contents are filled. As a result, the contents smoothly flow into one side of the hexagonal bottom. Once a sufficient amount of the contents has flowed into the hexagonal bottom, the hexagonal bottom is folded back along the first fold line and smoothly expanded. Forming the Z-shaped fold of the inner bag can be easily and automatically performed using machinery commonly used in bag manufacturing and well known to those skilled in the art. Therefore, single-bottomed bags constructed according to the present invention can be easily and automatically manufactured using machinery without requiring manual labor and without reducing production efficiency. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a front view of a preferred embodiment of a single bottom bag constructed in accordance with the present invention; [Figure 2] 2 is a schematic cross-sectional view of the single bottom bag shown in FIG. 1 taken along line II-II in FIG. [Figure 3] 2 is a schematic cross-sectional view taken along line II-II in FIG. 1, showing the behavior of the single-bottomed bag shown in FIG. 1 when filling the contents. [Figure 4] 2 is a schematic cross-sectional view taken along line II-II in FIG. 1, showing the state in which the one-side-sealed bag shown in FIG. 1 has been completely filled with a specified amount of contents. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will now be described in further detail with reference to the accompanying drawings, which show preferred embodiments of a single-bottom bag constructed according to the present invention.

[0014] 1 and 2, a single-bottomed bag constructed according to the present invention, generally designated by the numeral 2, includes an outer bag 4 and an inner bag 6. As shown in FIG.

[0015] The outer bag 4 can be made of a single layer or multiple layers of paper selected from suitable papers such as kraft paper, polylaminated paper, and cross-kraft paper. The outer bag 4 is formed into a cylindrical shape by laminating both widthwise edge portions of rectangular paper sheets and gluing them over the entire laminated area, and then flattening them. The opening edge 8 (the upper edge in FIGS. 1 and 2) of the outer bag 4 is open. The bottom end of the outer bag 4 is set to a hexagonal base 10. That is, the outer bag 4 is folded along a first fold line 14 extending parallel to the bottom edge 12, then unfolded about the first fold line 14 to form triangular folds (shown by two-dot chain lines 16 in FIG. 1) on both sides in the width direction (left-right direction in FIG. 1). The bottom edge is then folded inward along a pair of second fold lines 18 located on both sides of the first fold line 14 in the length direction (top-bottom direction in FIG. 1), overlapping and affixing (shown as black 19 in FIG. 2) to form the hexagonal bottom 10. If necessary, a rectangular piece of paper can be affixed to the hexagonal bottom 10 of the outer bag 4, as shown by two-dot chain lines 20 in FIG. 1. The configuration of the outer bag 4 itself is well known to those skilled in the art and does not constitute a novel feature of the single-bottom bag 2 constructed in accordance with the present invention, so a detailed description thereof will be omitted.

[0016] Continuing the explanation with reference to Figures 1 and 2, the inner bag 6 is flattened and cylindrical (tubular) and is made of an appropriate synthetic resin film such as a low-density polyethylene (LDPE) film, a linear low-density polyethylene (L-LDPE) film, a high-density polyethylene (HDPE) film, a polypropylene (PP) film, or a polyethylene terephthalate (PET) film. Generally, in the case of soft synthetic resins, a film is defined as a film having a thickness of less than 0.254 mm, and a sheet is defined as a film having a thickness of 0.254 mm or more. In the case of hard synthetic resins, a film is defined as a film having a thickness of less than 0.076 mm, and a sheet is defined as a sheet having a thickness of 0.076 mm or more. However, the term "synthetic resin film" used in the claims and specification of this patent is not limited to a thickness of less than 0.254 mm or less than 0.076 mm, but includes a thickness of 0.254 mm or more or 0.076 mm or more. The bottom end of the inner bag 6 is sealed by joining the entire laminated area, for example, by heat sealing (the joining area is shown as a black mark 22 in Figure 2). The opening edge 23 of the inner bag 6 (the upper edge in Figures 1 and 2) is open.

[0017] The tubular inner bag 6 made of synthetic resin film may have a width (circumferential) dimension substantially equal to that of the outer bag 4, but its length is greater than that of the outer bag 4. As shown in Figure 2, it is important that the inner bag 6 has a Z-shaped folded portion 24. This Z-shaped folded portion 24 is located between the first fold line 14 and the opening edge (upper edge in Figures 1 and 2) 23, preferably approximately midway between them. And, The length L1 of the Z-shaped folded portion 24 in the longitudinal direction (the vertical direction in FIG. 2) is about 20 to 160 mm. above The length L2 in the longitudinal direction (the vertical direction in Figs. 1 and 2) of the hexagonal base 10 is 0.5 times or less (L1 ≦ 0.5L2). Ru( The reason for this will be explained later.)

[0018] As can be clearly seen from FIG. 2, it is advantageous for the outer surface of the inner bag 6 to be joined to the inner surface of the outer bag 4 at the open end (the joined portion is indicated by a black dot 26 in FIG. 2). (For example, if the open ends of the outer bag and the inner bag are manually or mechanically gripped to prevent relative movement between them when filling the bag with contents, the joining of the outer surface of the inner bag 6 to the inner surface of the outer bag 4 at the open end can be omitted.) Such joining may be performed at multiple locations spaced apart in the width direction or continuously in the width direction, and may be performed by adhesive or heat welding. Furthermore, when the contents contained in the bag 2 are to be used in a clean room, it is desirable to detach the outer bag 4 from the inner bag 6 and bring only the inner bag 6 containing the contents into the clean room. In such cases, a releasable adhesive may be used for the joining. The bottom end of the inner bag 6 is folded into a U shape along the first fold line 14, and further folded into a U shape along one of the pair of second fold lines 18 (the second fold line 18 located on the open end side when the hexagonal bottom 10 is folded along the first fold line 14, i.e., the state shown in FIG. 2). As clearly shown in FIG. 2, the outer surface of the portion of the bottom end of the inner bag 6 folded along one of the second fold lines 18 facing the inner surface of the outer bag 4 is preferably joined to the inner surface of the outer bag 4 (such joined portion is indicated by a black mark 28 in FIG. 2). This joint 28, like the joint 26, may be made at multiple portions spaced apart in the width direction or may be made continuously in the width direction. It may be joined using an adhesive or by heat welding, or it may be joined in a releasable manner using an adhesive with excellent releasability.

[0019] In the bag 2 described above, when contents (not shown) are filled into the inner bag 6 through the open edge, as shown in FIG. 3, the filled contents flow downward within the inner bag 6, and one side of the Z-shaped folded portion 24 of the inner bag 6 (the right side in FIG. 2) moves downward along with the downward flow of the contents. Therefore, the contents smoothly flow into the lower portion of the hexagonal bottom 10 (the portion located below when the hexagonal bottom 10 is folded along the first fold line 14). When a sufficient amount of contents has flowed in, the hexagonal bottom 10 is folded back along the first fold line 14 and expanded to a substantially horizontal position, as shown in FIG. 4. Thus, the specified amount of contents is filled smoothly and sufficiently into the bag 2. As described above, the longitudinal length L1 of the Z-shaped folded portion 24 (the vertical direction in FIG. 2) is approximately 20 to 160 mm. above The length L2 in the longitudinal direction (the vertical direction in Figs. 1 and 2) of the hexagonal base 10 is 0.5 times or less (L1 ≦ 0.5L2). do. If the length L1 of the Z-shaped fold 24 is too short, one side of the inner bag 6 will not move sufficiently into the hexagonal bottom 10, which will tend to result in insufficient flow of the contents into the hexagonal bottom 10. On the other hand, if the length L1 of the Z-shaped fold 24 is too long, the inner bag 6 will fold over itself near the hexagonal bottom 10 when the contents are discharged from the bag 2, causing excessive retention and hindering discharge of the contents near the hexagonal bottom 10. [Explanation of symbols]

[0020] 2: Bag 4: Outer bag 6: Inner bag 8: Opening edge 10:Hexagonal bottom 12: Bottom edge 14: First fold line 16: Triangular folding section 18: Second fold line 19: Joint 20: Power paper 22: Joint 23: Opening edge 24: Z-shaped folded part 26: Joint 28: Joint

Claims

1. A single-bottom sealed bag comprising a cylindrical outer bag and a cylindrical inner bag formed from a synthetic resin film and closed at its bottom end, the bottom end of the outer bag being folded along a first fold line parallel to the bottom edge, the outer bag being opened about the first fold line to form triangular folded portions on both sides in the width direction, the bottom edge being folded inward along a pair of second fold lines located on both sides of the first fold line in the longitudinal direction and parallel to the first fold line, and overlapping and affixed to form a hexagonal bottom, the bottom end of the inner bag being folded into a U shape along the first fold line and further folded into a U shape along one of the pair of second fold lines, The length of the inner bag is greater than the length of the outer bag, and a Z-shaped folded portion is formed in the inner bag between the first fold line and the opening edge, The single-bottom bag is characterized in that the longitudinal length L1 of the Z-folded portion of the inner bag is 20 to 160 mm and is not more than 0.5 times the longitudinal length L2 of the hexagonal bottom.

2. 2. The single-bottom bag according to claim 1, wherein the outer surface of the bottom end of the inner bag, which is folded along one of the second fold lines and faces the inner surface of the outer bag, is bonded to the joint of the outer bag.

3. 2. The single-bottom bag according to claim 1, wherein the outer surface of the inner bag is joined to the inner surface of the outer bag at the open end.

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