Film Bag
The film bag design with a specific seal configuration and leg structure prevents wrinkles, ensuring easy folding and compact storage, even when filled with liquids.
Patent Information
- Application Number
- JP2020095375
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2020-06-01
- Publication Date
- 2026-01-06
- Estimated Expiration
- 2040-06-01
AI Technical Summary
Conventional film bags tend to form wrinkles at the folded portions when bent or folded, which affects their compactness and usability, especially when holding liquids.
The film bag design includes a first seal portion, a second seal portion with a horizontal portion and legs, and curved portions that extend from the horizontal portion, with the horizontal length being between 30% to 70% of the side seal distance, and corner portions exposed to the storage chamber, to prevent wrinkles.
The design effectively prevents wrinkles at the folded portions, allowing the bag to be easily folded and unfolded without bulging or deforming, maintaining compactness and preventing overflow when filled with liquids.
Smart Images
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Abstract
Description
[Technical Field]
[0001] The present invention relates to a film bag. [Background technology]
[0002] A conventional film bag is disclosed, for example, in Japanese Patent Laid-Open Publication No. 2005-131221 (Patent Document 1). [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-131221 Summary of the Invention
[0004] The above-mentioned Patent Document 1 discloses a configuration in which, when the bag is hung on the production line, the bottom seal portion located below the storage chamber is configured in a mountain-like shape that protrudes above the horizontal line connecting the lower ends of the two side seal portions. [Problem to be solved by the invention]
[0005] However, with this configuration, there is a problem in that when the sheet is bent, wrinkles tend to form at the bent portion.
[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a film bag that is less likely to wrinkle at the folded portions. [Means for solving the problem]
[0007] The film bag according to this invention is a film bag having one storage chamber formed by sealing the periphery of two opposing film sheets, and comprises a first seal portion having an opening, a second seal portion opposite the first seal portion, and a pair of side seal portions connecting the first and second seal portions and extending along an axial direction from the first seal portion toward the second seal portion, the second seal portion comprising a horizontal portion extending horizontally facing the storage chamber and connecting the pair of side seal portions, and a pair of legs located on both sides of the horizontal portion, the pair of legs extending away from the horizontal portion and the first seal portion along the axial direction, and the horizontal length (W1) of the horizontal portion being 30% or more and 70% or less of the horizontal distance (W2) between the pair of side seal portions.
[0008] In a film bag configured in this manner, the occurrence of wrinkles in the folded portion can be prevented.
[0009] Preferably, the housing further comprises a curved portion that curves toward the pair of legs, the position where the curve starts being located between the horizontal portion and the first seal portion.
[0010] Preferably, the second seal portion has at least one corner portion that is exposed to the storage chamber in a portion that continues from the horizontal portion to the leg portion.
[0011] Preferably, the corners are spaced apart from one another. [Brief explanation of the drawings]
[0012] [Figure 1] FIG. 1 is a front view of a paper bag illustrating the concept of the present invention. [Figure 2] FIG. 1 is a side view of a paper bag to illustrate the concept of the present invention. [Figure 3] FIG. 1 is a front view of a paper bag with legs to illustrate the concept of the present invention. [Figure 4] FIG. 1 is a side view of a paper bag with legs to illustrate the concept of the present invention. [Figure 5] 1 is a perspective view of a paper bag provided with legs to illustrate the concept of the present invention. FIG. [Figure 6] FIG. 2 is a front view of the film bag according to the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 2 is a perspective view of the film bag according to the first embodiment as viewed from below. [Figure 9] FIG. 10 is a front view of a film bag according to a second embodiment. [Figure 10] FIG. 10 is a front view of a film bag of a comparative example. [Figure 11] FIG. 2 is a front view of the film bag before the center portion is folded. [Figure 12] FIG. 10 is a front view of the film bag after the center portion is folded. [Figure 13] FIG. 2 is a plan view of a circular film bag. [Figure 14] FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. [Figure 15] FIG. 1 is a plan view of a circular film bag filled with water. [Figure 16] FIG. 16 is a cross-sectional view taken along line XVI-XVI in FIG. [Figure 17] FIG. 1 is a plan view of a square film bag. [Figure 18] FIG. 1 is a plan view of a square film bag filled with water. [Figure 19] 10 is a diagram showing the state in which the side seal portion on the arrow XIX side is pulled inward and curved as the bag expands. FIG. [Figure 20] 10 is a side view of the film bag before being lifted, as seen from the direction in which the rod-shaped member extends. FIG. [Figure 21] 10 is a side view of the film bag being lifted, seen from the direction in which the rod-shaped member extends. FIG. [Figure 22] FIG. 10 is a plan view of the film bag and the rod-shaped member before being lifted. [Figure 23] FIG. 10 is a plan view of the film bag and the rod-shaped member during lifting. [Figure 24]FIG. 24 is a cross-sectional view taken along line XXIV-XXIV in FIG. 22. [Figure 25] FIG. 24 is a cross-sectional view taken along line XXV-XXV in FIG. 23. [Figure 26] FIG. 10 is a plan view of the film bag and the rod-shaped member before being lifted. [Figure 27] FIG. 10 is a plan view of the film bag and the rod-shaped member during lifting. [Figure 28] FIG. 2 is a plan view of a film bag having legs and a rod-shaped member. [Figure 29] FIG. 10 is a plan view of a film bag with legs and a rod-shaped member during lifting. [Figure 30] 10 is a diagram showing the direction of the force acting on the right side seal by the wrinkle 36. FIG. [Figure 31] 10 is a diagram showing the direction of the force acting on the left side seal by a wrinkle 46. FIG. DETAILED DESCRIPTION OF THE INVENTION
[0013] (Embodiment 1) The present inventors have conducted extensive research in the field of film bags to prevent wrinkles from occurring at the folded portions.
[0014] Film bags are widely used as containers for holding liquids. Liquids such as food, medicine, and daily necessities are sealed inside the film bags. Film bags are required to be compactly packaged when filled with liquid. Folding a large film bag in half makes it particularly compact. However, when folded, wrinkles can sometimes form at the folds. Therefore, we investigated a film bag shape that would prevent wrinkles from forming at the folds.
[0015] By focusing on the seal shape of the film bag and the space capacity under gravity load, we found that changing the shape of the film bag makes it less likely for wrinkles to occur at the folded parts.
[0016] To fold the film bag easily, it is necessary to design the film bag so that the water in the folded area can easily flow along the length of the film bag toward the port and the bottom. To achieve this, it is necessary to provide space for the liquid to flow inside the film bag when it is folded. Furthermore, providing space inside the film bag not only makes it easier to fold in half, but also prevents overflow when filling the film bag with liquid by hanging it from the port.
[0017] When water is poured into a film bag that has been sealed around the edges to form a perfect square, the water enters the four corners and tries to push outward, which in turn pulls the sheet. As a result, a force acts in the direction that prevents the film bag from expanding in thickness, preventing it from deforming into a shape that ensures sufficient capacity. Therefore, the inventor attempted to solve this problem by adopting a "gusset" like those used in paper bags.
[0018] Fig. 1 is a front view of a paper bag to illustrate the concept of the present invention. Fig. 2 is a side view of a paper bag to illustrate the concept of the present invention. Fig. 3 is a front view of a paper bag provided with legs to illustrate the concept of the present invention. Fig. 4 is a side view of a paper bag provided with legs to illustrate the concept of the present invention. Fig. 5 is a perspective view of a paper bag provided with legs to illustrate the concept of the present invention.
[0019] As shown in Figures 1 to 5, fold lines 101 and 102 are provided on paper bag 100. Fold line 101 is provided on the side of paper bag 100, and fold line 102 is provided on the bottom of paper bag 100. By folding paper bag 100 at fold lines 101 and 102, legs 103 and 104 are formed on the bottom of paper bag 100. Forming legs 103 and 104 makes it easier to ensure thickness A for the paper bag.
[0020] The two sheets of paper are transformed into a rectangular parallelepiped by providing a gusset in the paper bag 100. Although it is not possible to provide a gusset in a film bag, we have devised a shape that automatically expands the film bag by providing a part that functions as a gusset when water is poured into it.
[0021] Fig. 6 is a front view of the film bag according to embodiment 1. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. Fig. 8 is a perspective view of the film bag according to embodiment 1 as seen from below.
[0022] As shown in FIGS. 6 to 8, the film bag 1 is a film bag 1 having one storage chamber 2 configured by sealing the peripheries of two opposing film sheets 5 and 6.
[0023] The film bag 1 comprises a first seal portion 10 having a mouth portion 11, a second seal portion 20 opposite the first seal portion 10, and a pair of side seal portions 30, 40 connecting the first seal portion 10 and the second seal portion 20 and extending along the axial direction from the first seal portion 10 toward the second seal portion 20.
[0024] The second seal portion 20 includes a horizontal portion 21 that faces the storage chamber 2 and extends horizontally between the pair of side seal portions 30, 40, and a pair of legs 3, 4 located on both sides of the horizontal portion 21.
[0025] The pair of legs 3, 4 extend axially away from the horizontal portion 21 and the first seal portion 10. The horizontal length (W1) of the horizontal portion 21 is 30% to 70% of the horizontal distance (W2) between the pair of side seal portions 30, 40.
[0026] In the film bag 1 configured in this manner, the occurrence of wrinkles in the folded portions can be prevented.
[0027] The side seal portions 30, 40 have curved portions 32, 42 that curve toward the pair of legs 3, 4. The positions 33, 43 where the curves start are located between the horizontal portion 21 and the first seal portion 10.
[0028] At least one corner 24, 25 is provided in the second seal portion 20 at a portion continuing from the horizontal portion 21 to the leg portions 3, 4 so as to be exposed to the storage chamber 2. A plurality of corners 24, 25 are provided at intervals from one another.
[0029] The side seal portions 30, 40 are provided with side point seals 31, 41 as a pair of protrusions that protrude inward. The side point seals 31, 41 are provided to prevent wrinkles from forming in the side seal portions 30, 40. The pair of side point seals 31, 41 do not necessarily have to be provided. The provision of corner portions 24, 25 makes wrinkles 111, 112 more likely to form. The second seal portion 20 is provided with a hole 23 for hanging the film bag 1. The corner portions 24, 25 are provided on the bottom 22 of the second seal portion 20.
[0030] A liquid 50 is sealed in the storage chamber 2. The liquid 50 is, for example, physiological saline, a medicine, water, etc. The film sheets 5 and 6 are expanded so that the circle 2a fits between them.
[0031] To allow the legs 3, 4 to easily spread apart, curved portions 32, 42 are employed as arc-shaped curves that gradually become gentler from the bottom of the legs 3, 4.
[0032] By inducing the inward folding of the legs 3 and 4, it is possible to increase the thickness of the leg 3. For this reason, the provision of two corners 24 and 25 forces the formation of wrinkles in the film bag 1. The angle θ1 of the corner 24 and the angle θ2 of the corner 25 are, for example, 40°.
[0033] In the film bag 1 configured as described above, when the center portion is pulled up and folded in half, drainage occurs instantly at the fold. This is also due to the effect of liquid being pulled from the vicinity of the mouth portion 11 and the bottom 22, which act as ports, making it possible to manufacture a film bag that is less likely to wrinkle at the fold.
[0034] In addition, when the film bag 1 is laid flat, it is possible to prevent the center of the film bag 1 from bulging out. Furthermore, since the bottom 22 does not protrude to either side, it can be stored compactly in a packing case.
[0035] (Embodiment 2) Fig. 9 is a front view of a film bag according to embodiment 2. As shown in Fig. 9, film bag 1 according to embodiment 2 differs from film bag 1 according to embodiment 1 in that positions 33, 34 where the curvature of a pair of side seal portions 30, 40 begins are located below horizontal portion 21.
[0036] (Example) In the example, the film bag 1 shown in Fig. 6, the film bag 1 shown in Fig. 6 with the corners 24 and 25 removed, the film bag shown in Fig. 9, and the comparative film bag shown in Fig. 10 were prepared. The volume of each film bag was 2 dm 3 The dimensions of each film bag are shown in Table 1.
[0037] [Table 1]
[0038] Fig. 10 is a front view of a film bag of a comparative example. The film bag 201 in Fig. 10 has one storage compartment 202 formed by sealing the peripheries of two opposing film sheets. The film bag 201 has a first sealed portion 210 having an opening 211, a second sealed portion 220 facing the first sealed portion 210, and a pair of side sealed portions 230, 240 that connect the first sealed portion 210 and the second sealed portion 220 and extend along the axial direction from the first sealed portion 210 toward the second sealed portion 220.
[0039] The center of the second seal portion 220 protrudes toward the first seal portion 210. The protruding portion has a height H1. A hole 223 is formed in the second seal portion 220.
[0040] FIG. 11 is a front view of a film bag before the center is folded. FIG. 12 is a front view of the film bag after the center is folded. A folding test was conducted using the device shown in FIG. 11. A rod-shaped member 501 was contacted with the center of the film bag in the longitudinal direction, and the bag was lifted 10 cm to the state shown in FIG. 12. This was repeated 100 times. The number of times wrinkles occurred at contact portion 502 that came into contact with rod-shaped member 501 was measured. Wrinkles were determined when the sheet was folded twice in the longitudinal direction of the bag and the width was 2 mm or more. The results are shown in Table 1.
[0041] In the "Rating" column of Table 1, rating AA indicates that no wrinkles occurred in the contact portion 502. Rating A indicates that wrinkles occurred in the contact portion 502 one to five times. Rating B indicates that wrinkles occurred in the contact portion 502 six or more times. However, there was no rating A in Table 1.
[0042] It can be seen that excellent effects were achieved in Samples No. 1 to 3. The reasons why the above results were obtained in the examples will be explained below.
[0043] Fig. 13 is a plan view of a circular film bag. Fig. 14 is a cross-sectional view taken along line XIV-XIV in Fig. 13. Fig. 15 is a plan view of a circular film bag containing water. Fig. 16 is a cross-sectional view taken along line XVI-XVI in Fig. 15.
[0044] A round bag 1 is made from two sheets 5 and 6. In Figures 13 and 14, D1 is 300 mm and the circumference is 942 mm. When water is poured into the bag, it deforms as shown in Figures 15 and 16, and the diameter becomes smaller. D2 becomes 290 mm and the circumference is 911 mm.
[0045] As the diameter of the sealed portion of the circumference becomes smaller, a force acts on it that causes it to shrink more than its actual length, making it more susceptible to wrinkles 5a. If a sheet with a diameter of 300 mm is filled with water about 20 mm thick, the diameter will decrease by about 10 mm and the circumference will shrink by about 30 mm (about 3%).
[0046] Figure 17 is a plan view of a square film bag. Figure 18 is a plan view of a square film bag with water inside.
[0047] When a square film bag 1 is filled with water, it deforms in a direction that shortens its overall length and width, as in Figures 13 to 16, and the four corners protrude outward. At this time, a force acts to bend the seal toward the inside of the bag, and wrinkles are likely to form, especially at the corners. Figure 19 shows how the side seal on the arrow XIX side is pulled inward and bent as the bag expands.
[0048] Next, consider the deformation that occurs when the film bag 1 is lifted as shown in FIG.
[0049] Figure 20 is a side view of the film bag before it is lifted, as seen from the direction in which the rod-shaped member extends. Figure 21 is a side view of the film bag during lifting, as seen from the direction in which the rod-shaped member extends. As shown in Figures 20 and 21, when the film bag is lifted, the liquid inside moves to both sides, and a force acts in a direction that expands the thickness of the film bag 1. At the same time, the length A of the film bag 1 tries to shrink to B.
[0050] Fig. 22 is a plan view of the film bag and the rod-shaped member before lifting. Fig. 23 is a plan view of the film bag and the rod-shaped member during lifting. Fig. 24 is a cross-sectional view taken along line XXIV-XXIV in Fig. 22. Fig. 25 is a cross-sectional view taken along line XXV-XXV in Fig. 23.
[0051] The side seals 30, 40 of the film bag 1 form wrinkles and fold inward to maintain balance due to the force that tries to shorten their overall length. Figures 23 and 25 show an example where the fold occurs at the lifted position. In this case, the side seals 30, 40 try to slip between the upper and lower sheets 5, 6. Furthermore, the upper and lower sheets 5, 6 push out in the directions indicated by arrows 35, 45, covering the side seals 30, 40, resulting in a double fold.
[0052] Figure 26 is a plan view of the film bag and rod-shaped member before lifting. Figure 27 is a plan view of the film bag and rod-shaped member during lifting. However, wrinkles may occur in places other than the contact points with the lifting rod-shaped member 501. In the case shown in Figure 27, double folding does not occur in the folded-in-half portion. Therefore, double folding in the folded-in-half portion can be prevented by intentionally creating wrinkles in places other than the lifted portion. For this reason, side point seals 31, 41 on both sides of the film bag 1 are effective.
[0053] Figure 28 is a plan view of the film bag with legs and the rod-shaped member. Figure 29 is a plan view of the film bag with legs and the rod-shaped member during lifting.
[0054] Another method is also available for creating wrinkles on the bottom edge of film bag 1. Wrinkles 36 and 46 are created by lifting. The bottom edge is lifted by planar extension portion 9, but wrinkles 36 and 46 shrink the bag in the left-right direction, causing the bag to deform into a trapezoid shape overall and canceling the force of shrinkage of the side seal. This prevents wrinkles from forming near rod-shaped member 501. Figure 30 shows the direction of the force acting on the right side seal by wrinkle 36. Figure 31 shows the direction of the force acting on the left side seal by wrinkle 46.
[0055] The embodiments and examples disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]
[0056] 1,201 film bag, 2,202 storage chamber, 2a circle, 3,4,103,104 legs, 5,6 film sheet, 9 flat extending portion, 10,210 first seal portion, 11,211 mouth portion, 20,220 second seal portion, 21 horizontal portion, 22 bottom, 23,223 hole, 24,25 corner portion, 30,40,230,240 side seal portion, 31,41 side point seal, 32,42 curved portion, 33,34,43,44 position, 36,46,111,112 wrinkle, 50 liquid, 100 paper bag, 101,102 fold line, 501 rod-shaped member, 502 contact portion.
Claims
1. A film bag having one storage chamber formed by sealing the peripheries of two opposing film sheets, the film bag comprising: a first sealed portion having an opening; a second sealed portion opposed to the first sealed portion; and a pair of side sealed portions connecting the first and second sealed portions and extending along an axial direction from the first sealed portion toward the second sealed portion, the pair of side sealed portions being formed by sealing the peripheries of the two opposing film sheets; the second seal portion includes a horizontal portion extending horizontally and connecting the pair of side seal portions facing the storage chamber, and a pair of leg portions located on both sides of the horizontal portion, the pair of leg portions extending along the axial direction so as to move away from the horizontal portion and the first seal portion, and the horizontal length (W1) of the horizontal portion is 30% to 70% of the horizontal distance (W2) between the pair of side seal portions, The film bag has a pair of side point seals that protrude inward, and further has a curved portion that curves toward the pair of leg portions, and the position where the curve begins is located between the horizontal portion and the first seal portion.
2. The film bag according to claim 1 , wherein the second seal portion has at least one corner portion that is exposed to the storage chamber in a portion that continues from the horizontal portion to the leg portion.
3. The film bag according to claim 2 , wherein a plurality of the corners are provided at intervals from each other.
Citation Information
Patent Citations
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