JP7780901B2 - freestanding bag - Google Patents

Description

This disclosure relates to a freestanding bag.

Standing pouches and other self-standing bags have been known in the past, each having a body and a bottom, with the bottom formed in a gusseted style (see, for example, Patent Documents 1 to 3).

JP 2012-66828 A JP 2011-195175 A Japanese Patent Application Laid-Open No. 2019-6435

Self-standing bags such as those described in Patent Document 1 have side seals on the left and right edges. Because these side seals are very rigid, they can cause discomfort when consumers hold them, such as pain when the side seals touch their hands. Furthermore, self-standing bags with side seals like those described in Patent Document 1 are manufactured by folding a bottom film in half with the base film layer (e.g., nylon) facing inward and the sealant layer (e.g., polyethylene) facing outward, inserting the folded bottom film between the front and back body films, and thermally bonding the peripheral edges of the bottom film and body film together. However, because the opposing surfaces of the bottom film facing inward in the folded state are made of a high-melting-point film such as nylon, they are not thermally bonded to each other. This can lead to unstable self-standing. To address this issue, a method is sometimes used in which cutouts are created in parts of the left and right edges of the bottom film to expose the body film, and the exposed body film is then thermally bonded together. However, this method requires additional manufacturing steps for the self-standing bag, and also generates waste material when creating the cutouts, resulting in relatively high costs. Additionally, because the scraps are small, they tend to scatter, resulting in poor production efficiency. Furthermore, the self-standing bags described in Patent Documents 2 and 3 have no side seals, but the bottom member and body are bonded with a separate adhesive member, resulting in a complex structure. This has led to problems such as reduced production efficiency and a high likelihood of manufacturing defects, including poor adhesion. Furthermore, the bags made of tubular film tend to become constricted or distorted due to their weak rigidity, making them unstable when standing upright.

The objective of this disclosure is to provide a free-standing bag that is comfortable to hold by the body, has a simple structure, is highly efficient to produce, and stands up stably.

The self-standing bag according to the present invention comprises a body portion having a flattened cylindrical body film with upper and lower openings and creases on the left and right edges, a folded portion folded in two, a facing portion facing the folded portion, a left side edge connecting the left end point of the folded portion and the left end point of the facing portion, and a right side edge connecting the right end point of the folded portion and the right end point of the facing portion, and a bottom film inserted into the lower end of the body portion with the folded portion facing up, wherein the body film and the bottom film are joined by a bottom adhesive portion, and the bottom adhesive portion includes a bottom adhesive portion that closes the bottom opening between point A1, which is the left end point of the folded portion, and point A2, which is the right end point of the folded portion, and the bag inner boundary line of the bottom adhesive portion is a line connecting point B1, which is located inside the bag more than point A1, and point B2, which is located inside the bag more than point A2, and has a linear shape that is convex toward the facing portion, and the self-standing bag The stand-up bag has a connecting adhesive part that is connected above the bottom adhesive part and bonds the inner surfaces of the body film together, and the connecting adhesive part is an area surrounded by point B1, point C1 which is the intersection of the folded-back part or an extension of the folded-back part and the left side edge, and point D1 which is a point on the left side edge and is above point C1, and point B2, point C2 which is the intersection of the folded-back part or an extension of the folded-back part and the right side edge, and point D2 which is a point on the right side edge and point D2, which is above point C2, and the bag inner boundary line of the lower end adhesive portion is curved, and points D1 and D2 are intersections of tangents at points B1 and B2 with the left edge and right edge, or the bag inner boundary line of the lower end adhesive portion is straight, and points D1 and D2 are intersections of extensions of the bag inner boundary line with the left edge and right edge .

In the self-standing bag according to the present invention, there is a gap between the inner wall at the left edge of the body portion and the left side of the bottom film and/or between the inner wall at the right edge of the body portion and the right side of the bottom film, and the inner surfaces of the body films are bonded together in the gap. The bottom adhesive portion further includes a left adhesive portion located a predetermined width from the left side and a right adhesive portion located a predetermined width from the right side. Preferably, point B1 is located more inward than point E1, which is a point on the folded portion of the bag's inner boundary line of the left adhesive portion, and point B2 is located more inward than point E2, which is a point on the folded portion of the bag's inner boundary line of the right adhesive portion. The presence of the gap allows the bottom film to be inserted more easily into the lower end of the body portion. The presence of the left adhesive portion and the right adhesive portion allows the non-adhesive portion, if any, to be sealed within the bottom adhesive portion.

In the self-standing bag according to the present invention, when the distance between the point C1 and the point D1 and the distance between the point C2 and the point D2 are H1, and the total length of the left edge and the total length of the right edge are L1, it is preferable that H1 be 0.05L1 or more and 0.50L1 or less. Since the connecting adhesive part does not extend to the gripping part of the body part, there is no discomfort when gripping the body part with the hand.

In the self-standing bag of the present invention, it is preferable that the body portion has a thick portion extending vertically from the body portion. This makes the bag more stable.

In the self-standing bag according to the present invention, it is preferable that the line connecting point B1 and point D1, and the line connecting point B2 and point D2, which are the bag's inner boundary lines of the connecting adhesive portion, are convex toward the outside of the bag. This more reliably prevents distortion or narrowing of the body.

In the self-standing bag according to the present invention, the top opening of the body portion may have a spout, a fitting, or a sealing seal.

The self-standing bag according to the present invention further has an additional adhesive portion connected to the connecting adhesive portion, which is an area surrounded by point B1, point D1, and point F1 on the left edge above point D1, and an area surrounded by point B2, point D2, and point F2 on the right edge above point D2, and it is preferable that the distance between point B1 and point D1 is the same as the distance between point D1 and point F1, and that the distance between point B2 and point D2 is the same as the distance between point D2 and point F2. By providing an additional adhesive portion in the shape of an isosceles triangle, distortion or narrowing of the body can be more reliably suppressed.

This disclosure makes it possible to provide a free-standing bag that does not cause discomfort when gripping the body with the hand, has a simple structure, is highly efficient to produce, and stands up stably.

1 is a front view showing a first example of a self-standing bag according to the present embodiment. FIG. 2 is a cross-sectional view taken along line XX in FIG. 1. FIG. 10 is a front view showing a second example of a self-standing bag according to the present embodiment. FIG. 10 is a front view showing a modified example of the first example of the self-standing bag according to the present embodiment. FIG. 10 is a front view showing a modified example of the second example of the self-standing bag according to the present embodiment.

Next, the present invention will be described in detail using embodiments, but the present invention should not be construed as being limited to these descriptions. Various modifications to the embodiments may be made as long as the effects of the present invention are achieved.

Figure 1 is a front view showing a first example of a self-standing bag according to this embodiment. Figure 2 is a cross-sectional view taken along line X-X in Figure 1. The self-standing bag 1 according to this embodiment comprises a body portion 10 having a cylindrical body film 2 flattened and having upper and lower openings and creases at a left edge 14 and a right edge 15, a folded portion 21 folded in two, a facing portion 22 facing the folded portion 21, a left side edge 23 connecting a left end point (point A1) of the folded portion 21 to a left end point of the facing portion 22, and a right side edge 24 connecting a right end point (point A2) of the folded portion 21 to a right end point of the facing portion 22, and a bottom portion 20 inserted into the lower end of the body portion 10 with the folded portion 21 facing up, and the body film 2 and the bottom film 3 are joined by a bottom adhesive portion 60, and the bottom adhesive portion 60 defines a bottom opening between point A1, which is the left end point of the folded portion 21, and point A2, which is the right end point of the folded portion 21. The bag includes a sealing bottom end adhesive portion 61, and the bag inner boundary line 61a of the bottom end adhesive portion 61 is a line connecting point B1, which is located inside the bag from point A1, and point B2, which is located inside the bag from point A2, and has a convex linear shape toward the facing portion 22. The freestanding bag 1 has connecting adhesive portions 71, 72 that connect above the bottom adhesive portion 60 and bond the inner surfaces of the body film 2 together. The connecting adhesive portions 71, 72 are an area 71 surrounded by point B1, point C1, which is the intersection of the folded portion 21 or an extension of the folded portion 21 and the left edge 14, and point D1, which is on the left edge 14 and is above point C1; and an area 72 surrounded by point B2, point C2, which is the intersection of the folded portion 21 or an extension of the folded portion 21 and the right edge 15, and point D2, which is on the right edge 15 and is above point C2.

The self-standing bag 1 has a body 10 and a bottom 20, with the bottom 20 being gusseted to allow it to stand on its own. As shown in Figure 2, the self-standing bag 1 has a storage chamber 13 for contents inside. Figure 1 shows the self-standing bag 1 in a flat state with no contents stored in the storage chamber 13, but by storing contents in the storage chamber 13, the folded bottom 20 opens in a gusset shape, allowing the self-standing bag 1 to stand stably.

As shown in Figures 1 and 2, the body portion 10 has a front portion 11 and a rear portion 12 and is flat when empty. The front portion 11 and the rear portion 12 are connected by folds at the left and right side edges 14, 15. "Flat" refers to the state in which the inner wall surfaces of the front portion 11 and the rear portion 12 are close to each other when the self-standing bag 1 is empty, resulting in an elongated cross-sectional shape of the self-standing bag 1. While typical self-standing bags have side seals at the left and right edges that bond the inner surfaces of the body film together, the self-standing bag 1 of this embodiment does not have side seals at the left and right edges 14, 15, but instead has folds. As a result, the side seals do not come into contact with the hand when the body portion 10 is held in the hand, creating no discomfort.

The body portion 10 is made of a body film 2. The body film 2 is preferably an inflation-molded film, as shown in FIGS. 1 and 2 . Since inflation-molded films are cylindrical, the body portion 10 can be seamless, such as by heat sealing. Alternatively, the body portion 10 may be formed into a cylindrical shape by using a single film as the body film 2 and attaching a spine to the film. For example, the body portion 10 may be formed into a cylindrical shape by butting both ends of a single film together without any gaps and then heat-sealing an adhesive film (not shown) on the inner surface of the film to form a spine. Alternatively, the body portion 10 may be formed into an envelope-like shape by bonding the inner surface of one side end of a single film to the outer surface of the other side end, or by bonding the inner surfaces of both side ends of a single film together. The envelope-like or palm-like bonding may be performed by heat sealing or using an adhesive. The body film 2 may be made of any of the materials listed below in <1> to <29>, but is not particularly limited in this embodiment. Of these, for example, polyethylene resin or polypropylene resin is preferable as the material for the body film 2. The body film 2 may include a porous substrate such as paper.
<1> High-density polyethylene (HDPE)
<2> Medium density polyethylene (MDPE)
<3> Low-density polyethylene (LDPE)
<4> Polypropylene (PP)
<5> Polyvinylidene chloride (PVDC)
<6> Polyvinyl chloride (PVC)
<7> Polystyrene (PS)
<8> Polyvinyl acetate (PVAc)
<9> Polytetrafluoroethylene (PTFE)
<10> ABS resin (acrylonitrile butadiene styrene resin)
<11> AS resin (SAN)
<12> Acrylic resin (PMMA)
<13> Polyamide (PA) / Product name: Nylon <14> Polyacetal (POM)
<15> Polycarbonate (PC)
<16> Modified polyphenylene ether (m-PPE, modified PPE, PPO)
<17> Polybutylene terephthalate (PBT)
<18> Polyethylene terephthalate (PET)
<19> Cyclic polyolefin (COP)
<20> Polyphenylene sulfide (PPS)
<21> Polysulfone (PSF)
<22> Polyethersulfone (PES)
<23> Amorphous polyarylate (PAR)
<24> Liquid crystal polymer (LCP)
<25> Polyether ether ketone (PEEK)
<26> Thermoplastic polyimide (PI)
<27> Polyamideimide (PAI)
<28> Thermoplastic polyurethane (TPU)
<29> Fluorine resin (PTFE)
The body film 2 may be a single-layer film or a laminate film. When the body film 2 is a single-layer film, its thickness is preferably about 0.2 to 1.5 mm. When the body film 2 is a laminate film, its thickness is preferably about 0.4 to 2.0 mm.

The bottom portion 20 closes the lower end of the body portion 10. When the storage chamber 13 is empty, the bottom portion 20 is folded inside the body portion 10, giving the self-standing bag 1 a flattened overall shape. However, when the storage chamber 13 is filled with contents, the bottom portion 20 unfolds, allowing the self-standing bag 1 to stand stably. The folded portion 21 is the crease where the bottom portion 20 is folded in half. The facing portion 22 is the lowest part of the bottom portion 20. The left side edge 23 is the part that faces the inner wall of the left edge 14 of the body portion 10 when the bottom film 3 is inserted into the lower end of the body portion 10. The right side 24 is the part that faces the inner wall of the right edge 15 of the body portion 10 when the bottom film 3 is inserted into the lower end of the body portion 10.

The material of the bottom film 3 can be any of the materials listed as materials for the body film 2. The material of the bottom film 3 may be the same as or different from the material of the body film 2.

The body film 2 and bottom film 3 are joined at the bottom adhesive portion 60. The bottom adhesive portion 60 is an adhesive portion that closes the bottom opening of the body portion 10 and includes a bottom adhesive portion 61. In this specification, each adhesive portion is preferably a thermally bonded portion, such as a heat seal. The self-standing bag 1 according to this embodiment can be mass-produced inexpensively and environmentally friendly by inserting the gusseted bottom portion 20 into the cylindrical body portion 10.

The bag inner boundary line 61a of the lower end adhesive portion 61 is a line connecting point B1, which is located on the bag inner side of point A1, and point B2, which is located on the bag inner side of point A2, and has a linear shape that is convex toward the opposing portion 22. In this specification, the bag inner boundary line refers to the boundary line of the adhesive portion on the storage chamber 13 side. The distance between points A1 and B1 and the distance between points A2 and B2 are preferably 3 to 20 mm each. The linear shape that is convex toward the opposing portion 22 may be, for example, an arc shape as shown in Figure 1, or, for example, an inverted trapezoid shape (not shown).

The bottom adhesive portion 60 may have a non-adhesive portion 69 where the body film 2 and the bottom film 3 are not adhered. If the bottom adhesive portion 60 has a large area, and the entire bottom adhesive portion 60 is an adhesive portion, excessive heat may be applied to the body film 2 and the bottom film 3, which may cause deformation or damage to the body film 2 and the bottom film 3. The non-adhesive portion 69 is provided to prevent this.

The self-standing bag 1 according to this embodiment includes configurations in which there is a gap 31 between the left and right side edges 14, 15 of the body film 2 and the left and right side edges 23, 24 of the bottom film 2 (shown in FIG. 1), and configurations in which there is no gap 31 between the left and right side edges 14, 15 of the body film 2 and the left and right side edges 23, 24 of the bottom film 2 (not shown). In the configuration in which there is a gap between the left and right side edges 14, 15 of the body film 2 and the left and right side edges 23, 24 of the bottom film 2 as shown in FIG. 1, the gap 31 preferably comprises a thermally bonded portion between the inner wall surface of the front portion 11 and the inner wall surface of the back portion 12 of the body film 2. As a result, in the self-standing bag 1, the lower end of the thermally bonded portion of the gap 31 and the lower end of the bottom adhesive portion 60 are in contact with each other. Therefore, the thermally bonded portion of the gap 31 acts as a pillar, enhancing the self-standing bag 1's ability to stand upright. Furthermore, in a configuration in which there are no gaps 31 between the left and right side edges 14, 15 of the body film 2 and the left and right side edges 23, 24 of the bottom film 2, the adhesive portion between the bottom film 3 and the front portion 11 and the adhesive portion between the bottom film 3 and the rear portion 12 in the bottom adhesive portion 60 may be separate from each other or may be joined to each other. When the adhesive portion between the bottom film 3 and the front portion 11 and the adhesive portion between the bottom film 3 and the rear portion 12 in the bottom adhesive portion 60 are joined to each other, a cutout (not shown) can be provided in the bottom film 3 to expose the inner wall surfaces of the front portion 11 and the rear portion 12, and the inner wall surfaces of the front portion 11 and the rear portion 12 can be bonded to each other in this exposed portion. In either case, the adhesive portion 60 between the bottom film 3 and the front portion 11 and the adhesive portion between the bottom film 3 and the rear portion 12 are separate from each other, or are joined together, the body portion 10 of the self-standing bag 1 is cylindrical, so the lower end of the bottom adhesive portion 60 touches the ground. This provides high self-standing ability.

In the self-standing bag 1 according to this embodiment, there is a gap 31 between the inner wall at the left edge 14 of the body portion 10 and the left side 23 of the bottom film 3 and/or between the inner wall at the right edge 15 of the body portion 10 and the right side 24 of the bottom film 3. The inner surfaces of the body film 2 are bonded together at the gap 31. The bottom adhesive portion 60 further includes a left adhesive portion 62 provided a predetermined width from the left side 23 and a right adhesive portion 63 provided a predetermined width from the right side 24. It is preferred that point B1 be located more inward from point E1, which is a point on the folded portion 21 of the bag inner boundary line 62a of the left adhesive portion 62, and point B2 be located more inward from point E2, which is a point on the folded portion 21 of the bag inner boundary line 63a of the right adhesive portion 63.

The gap 31 makes it easier to insert the bottom film 3 into the lower end of the body 10. The gap 31 may be located both between the inner wall at the left edge 14 of the body 10 and the left side 23 of the bottom film 3 and between the inner wall at the right edge 15 of the body 10 and the right side 24 of the bottom film 3, or it may be located only between the inner wall at the left edge 14 of the body 10 and the left side 23 of the bottom film 3, or only between the inner wall at the right edge 15 of the body 10 and the right side 24 of the bottom film 3. The widths L41 and L42 of the gap 31 are not particularly limited, but are preferably, for example, 1 to 15 mm.

By providing the left adhesive portion 62 and the right adhesive portion 63, if a non-adhesive portion 69 is provided within the bottom adhesive portion 60, the non-adhesive portion 69 can be sealed. The widths L51, L52 of the left adhesive portion 62 and the right adhesive portion 63 are not particularly limited, but are preferably 2 to 15 mm, and more preferably 5 to 10 mm. The distances between points E1 and B1 and between points E2 and B2 are preferably 3 to 20 mm, respectively. By providing the left adhesive portion 62 and the right adhesive portion 63, the inner surfaces of the body film 2 are adhered to each other at the gap 31, and the body portion 10 and bottom portion 20 can be more stably held without providing a notch (not shown) in the bottom film 3, allowing the self-standing bag 1 to stand on its own stably.

The connecting adhesive portions 71, 72 are adhesive portion 71 between the inner wall surface of the front portion 11 and the inner wall surface of the rear portion 12 in the area surrounded by points B1, C1, and D1, and adhesive portion 72 between the inner wall surface of the front portion 11 and the inner wall surface of the rear portion 12 in the area surrounded by points B2, C2, and D2. Points B1 and B2 are points on the folded portion 21 and face the storage chamber 13. Points C1 and C2 are the intersections of the extension of the folded portion 21 and the left edge 14 or the right edge 15 when the self-standing bag 1 is configured such that there are gaps between the left and right side edges 14, 15 of the body film 2 and the left and right side edges 23, 24 of the bottom film 2 as shown in Figure 1. Furthermore, points C1 and C2 are the intersections of the folded portion 21 and the left edge 14 or right edge 15 when the self-standing bag 1 is in a configuration where there is no gap between the left and right side edges of the body film and the left and right sides of the bottom film. In this configuration, points A1 and C1 coincide, and points A2 and C2 coincide, respectively. Points D1 and D2 are points on the left edge 14 or right edge 15, and are above points C1 or C2.

In the self-standing bag 1 according to this embodiment, point D1 is preferably the point at which the bag's inner boundary line 61a of the bottom adhesive portion 61 is extended to reach the left edge 14, and point D2 is preferably the point at which the bag's inner boundary line 61a of the bottom adhesive portion 61 is extended to reach the right edge 15. This provides more stable self-standing. If the bag's inner boundary line 61a of the bottom adhesive portion 61 is curved as shown in FIG. 1, points D1 and D2 are preferably the intersections of tangents to the endpoints (points B1 and B2) of the bag's inner boundary line 61a of the bottom adhesive portion 61 and the left edge 14 and right edge 15. If the bag's inner boundary line 61a of the bottom adhesive portion 61 is linear (not shown), points D1 and D2 are preferably the intersections of extensions of the bag's inner boundary line 61a of the bottom adhesive portion 61 and the left edge 14 and right edge 15.

1 shows, as an example, a configuration in which the bag inner boundary line 71a of the adhesive portion connecting points B1 and D1 of the connecting adhesive portions 71, 72 and the bag inner boundary line 72a of the adhesive portion connecting points B2 and D2 are straight lines, but this embodiment is not limited to this. FIG. 4 is a front view showing a modified example of a first example of a freestanding bag according to this embodiment. In the freestanding bag 1 according to this embodiment, the bag inner boundary lines 71a, 72a of the connecting adhesive portions 71, 72, the line connecting points B1 and D1 and the line connecting points B2 and D2, preferably have a convex shape that extends outward from the bag. The convex shape that extends outward from the bag may be, for example, a curved line (shown in FIG. 4), a dogleg shape (not shown), or an inverted dogleg shape (not shown). Of the bag inner boundary lines of the connected adhesive portions 71, 72, it is preferable that the line connecting points B1 and D1 is an arc of a circle or ellipse tangent to the left edge 14, as shown in Fig. 4, and the line connecting points B2 and D2 is an arc of a circle or ellipse tangent to the right edge 15. The arc of a circle or ellipse tangent to the left edge 14 and the arc of a circle or ellipse tangent to the right edge 15 both form a convex shape facing outward from the bag, as shown in Fig. 4. The line connecting points B1 and D1 may be a line formed by connecting a curve or straight line that smoothly continues into the bag inner boundary line 61a of the bottom end adhesive portion at point B1 with the arc of a circle or ellipse that has point D1 as its tangent point, and the line connecting points B2 and D2 may be a line formed by connecting a curve or straight line that smoothly continues into the bag inner boundary line 61a of the bottom end adhesive portion at point B2 with the arc of a circle or ellipse that has point D2 as its tangent point. The curve that smoothly continues to the bag inner boundary line 61a of the lower end adhesive portion is, for example, a curve with the same radius of curvature as the bag inner boundary line 61a of the lower end adhesive portion at point B1 or B2. The straight line that smoothly continues to the bag inner boundary line 61a of the lower end adhesive portion is, for example, a straight line that coincides with the tangent to the bag inner boundary line 61a of the lower end adhesive portion at point B1 or B2. Alternatively, the line connecting point B1 and point D1 may be a chord connecting both ends of an arc of a circle or ellipse that is tangent to the left edge 14, and the line connecting point B2 and point D2 may be a chord connecting both ends of an arc of a circle or ellipse that is tangent to the right edge 15. The chord connecting both ends of the arc of a circle or ellipse is a straight line. This more reliably suppresses distortion or necking of the body portion 10. Furthermore, in the self-standing bag 1 according to this embodiment, the line 71a connecting points B1 and D1 and the line 72a connecting points B2 and D2, which are the bag's inner boundary lines of the connecting adhesive portions 71, 72, may be convex toward the inside of the bag. The convex shape may be, for example, a curved line, a dogleg shape, or an inverted dogleg shape.

Figure 3 is a front view showing a second example of a self-standing bag according to this embodiment. As shown in Figure 3, the self-standing bag 1 according to this embodiment further includes additional adhesive portions 81 and 82 connected to the connecting adhesive portions 71 and 72. The additional adhesive portions 81 and 82 are the area surrounded by points B1, D1, and F1, a point on the left edge 14 located above point D1, and the area surrounded by points B2, D2, and F2, a point on the right edge 15 located above point D2. It is preferable that the distance between points B1 and D1 is the same as the distance between points D1 and F1, and that the distance between points B2 and D2 is the same as the distance between points D2 and F2. Providing the additional adhesive portions 81 and 82 in an isosceles triangular shape more reliably prevents distortion or narrowing of the body portion 10. Although the lines connecting points B1 and F1 and the lines connecting points B2 and F2 are shown as straight lines in FIG. 3 as an example, the present invention is not limited to this. FIG. 5 is a front view showing a modified example of a second example of a self-standing bag according to this embodiment. As shown in FIG. 5, the lines connecting points B1 and F1 and the lines connecting points B2 and F2 may have a convex shape that protrudes outward from the bag. The convex shape that protrudes outward from the bag may be, for example, a curved line (shown in FIG. 5), a dogleg shape (not shown), or an inverted dogleg shape (not shown). As shown in FIG. 5, it is preferable that the line connecting points B1 and F1 is an arc of a circle or an ellipse tangent to the left edge 14, and the line connecting points B2 and F2 is an arc of a circle or an ellipse tangent to the right edge 15. The line connecting points B1 and F1 may be a line connecting a curve or straight line that smoothly continues into the bag's inner boundary line 61a of the lower end adhesive portion at point B1 with a circular or elliptical arc that touches point F1, and the line connecting points B2 and F2 may be a line connecting a curve or straight line that smoothly continues into the bag's inner boundary line 61a of the lower end adhesive portion at point B2 with a circular or elliptical arc that touches point F2. The curve that smoothly continues into the bag's inner boundary line 61a of the lower end adhesive portion is, for example, a curve with the same radius of curvature as the bag's inner boundary line 61a of the lower end adhesive portion at point B1 or B2. The line that smoothly continues into the bag's inner boundary line 61a of the lower end adhesive portion is, for example, a straight line that coincides with the tangent to the bag's inner boundary line 61a of the lower end adhesive portion at point B1 or B2. This more reliably suppresses distortion or necking of the body portion 10.

1 and 3 to 5, for ease of explanation, the hatching of the bottom adhesive portion 61, the hatching of the connecting adhesive portions 71 and 72, the hatching of the left adhesive portion 62 and the right adhesive portion 63, the hatching of the adhesive portion between the inner wall surfaces of the body film 2 in the gap 31, and the hatching of the additional adhesive portions 81 and 82 (shown in FIGS. 3 and 5) are shown with different hatching, but these adhesive portions are actually connected to each other and integrated. The self-standing bag 1 according to this embodiment is made of a flexible packaging material and does not have side seals that bond the inner wall surfaces of the front portion 11 and the rear portion 12 to the left and right side edges 14 and 15. Therefore, if the contents are liquid or heavy, the weight of the contents may cause distortion or constriction near the bottom 20 of the left and right side edges 14 and 15. Therefore, in the self-standing bag 1 according to this embodiment, the provision of the connecting adhesive portions 71 and 72 distributes the internal pressure exerted on the body portion 10 and bottom portion 20 when contents are placed in the storage chamber 13 to points B1, C1, and D1, as well as points B2, C2, and D2 shown in FIG. 1 . This prevents distortion or necking of the body portion 10 even when the self-standing bag 1 is filled with contents, resulting in an aesthetically pleasing self-standing bag. Furthermore, the bottom adhesive portion 60 contains four films, including the front and back portions 11 and 12 of the body portion 10 and the two folded-back bottom films. The connecting adhesive portions 71 and 72 contain two films, including the front and back portions 11 and 12 of the body portion 10. This reduces the step between the bottom adhesive portion 60 and the connecting adhesive portions 71 and 72. This reduces stress concentration at the boundary between the bottom adhesive portion 60 and the connecting adhesive portions 71 and 72, making distortion or necking less likely to occur.

In the self-standing bag 1 according to this embodiment, as shown in Figure 1, when the distance between points C1 and D1 and the distance between points C2 and D2 are H1, and the total length of the left edge 14 and the total length of the right edge are L1, H1 is preferably 0.05L1 or more and 0.50L1 or less. By setting H1 relative to L1 within this range, the connecting adhesive portions 71, 72 do not extend to the grippable portion of the body portion 10, so that the body portion 10 does not feel uncomfortable when gripped by hand. H1 is more preferably 0.10L1 or more and 0.30L1 or less, and even more preferably 0.15L1 or more and 0.20D1 or less.

In the self-standing bag 1 according to this embodiment, as shown in FIG. 1, the body 10 preferably has a thick portion 16 extending in the vertical direction of the body 10. The provision of the thick portion 16 increases the rigidity of the body 10, further improving its self-standing stability and shape retention. The thick portion 16 is preferably not provided on the left or right side edges 14, 15, but is provided on the front portion 11 and rear portion 12. The thick portion 16 may be integral with the body film 2 (as shown in FIG. 2) or may be separate from the body film 2 (not shown). The thick portion 16 may be, for example, a protruding rib or a male or female component of a fitting. There is no particular limitation on the number of thick portions 16, but it is preferable that there be between two and ten.

In the self-standing bag 1 according to this embodiment, the upper end of the body 10 includes a spout 30, as shown in FIG. 1 . Providing a spout 30 at the upper end of the body 10 allows the self-standing bag 1 to serve as a substitute for PET bottles. For example, from an environmental conservation perspective, many municipalities require that the cap and printed shrink label be separated from the bottle body before disposal. This process takes time for consumers, and there is a risk of injuring their fingernails or fingers when removing the shrink label. The self-standing bag 1 according to this embodiment can be printed directly on the body 10, eliminating the need to separate the label when discarding, and can be discarded without separating it from the spout 30. This not only simplifies disposal with household waste, but also contributes to reducing work time, disposal costs, and labor costs at restaurants. Because the self-standing bag 1 uses less resin than PET bottles, it can be crushed after use, dramatically reducing waste. Furthermore, the self-standing bag 1 can be washed after use and reused like a PET bottle, reducing environmental impact. The self-standing bag 1 can be manufactured more cheaply than plastic bottles, so the economic benefits are immeasurable.

In the self-standing bag 1 according to this embodiment, the upper end of the body portion 10 may have a fitting (not shown) or a sealing seal (not shown). The fitting is, for example, a female-male interlocking zipper having a male member and a female member. The sealing seal is the portion at the upper end of the body portion 10 where the inner wall surface of the front portion 11 and the inner wall surface of the rear portion 12 are bonded together.

The total length L1 of the left and right side edges 14, 15 is not particularly limited, but is preferably 80 to 200 mm, for example. The height L2 from the opposing portion 22 of the bottom 20 to the folded portion 21 is not particularly limited, but is preferably 10 to 50 mm, for example. The width between the left and right side edges 14, 15 is not particularly limited, but is preferably 50 to 200 mm, for example, and more preferably 70 to 150 mm.

The manufacturing method of the self-standing bag 1 according to this embodiment is not particularly limited, but may use a tubular inflation-molded film as the body film 2, or a single body film formed into a tubular shape by, for example, gluing the back of the body film. A preferred method is to insert a bottom film 3 folded in half into the tubular body film 2 and bond the peripheral edges of the bottom film and the body film together. Alternatively, a method may be used in which a bottom film 3 folded in half is placed on top of a single body film 2, and the body film 2 is then formed into a tubular shape by, for example, gluing the back of the body film, and the peripheral edges of the bottom film and the body film are bonded together. In the self-standing bag 1 according to this embodiment, if the bottom film 3 is a laminated film, the opposing surfaces of the bottom film 3 facing inward in the folded state are not thermally bonded to each other because they are made of a high-melting-point film such as nylon. However, in the self-standing bag 1 according to this embodiment, the tubular shape of the body film 2 allows the lower end of the bottom adhesive portion 60 to contact the ground, allowing the bag to stand stably. Furthermore, by not adhering the opposing surfaces of the bottom film 3 that face inward when folded in half, the bottom expands smoothly when contents are placed inside. Furthermore, there is no need to create a cutout, so production efficiency is not compromised.

1 Self-standing bag 2 Body film 3 Bottom film 10 Body 11 Front portion 12 Rear portion 13 Storage chamber 14 Left edge 15 Right edge 16 Thick portion 20 Bottom 21 Folded portion 22 Facing portion 23 Left side 24 Right side 30 Spout 31 Gap 60 Bottom adhesive portion 61 Lower end adhesive portion 61a Bag inner boundary line 62 of lower end adhesive portion Left side adhesive portion 62a Bag inner boundary line 63 of left adhesive portion Right adhesive portion 63a Bag inner boundary line 69 of right adhesive portion Non-adhesive portions 71, 72 Connecting adhesive portions 71a, 72a Bag inner boundary lines 81, 82 of connected adhesive portions Additional adhesive portion 900 Self-standing bag 914, 915 Left and right side edges 910 Body 920 Bottom

Claims (7)

a cylindrical body portion having an upper end opening and a lower end opening, a flattened body film, and folds on the left and right edges;
a bottom film having a folded portion folded in two, an opposing portion opposing the folded portion, a left side edge connecting the left end point of the folded portion and the left end point of the opposing portion, and a right side edge connecting the right end point of the folded portion and the right end point of the opposing portion, and the bottom film is inserted into the lower end of the body portion with the folded portion facing up,
The body film and the bottom film are joined at a bottom adhesive portion,
the bottom adhesive portion includes a lower end adhesive portion that seals the lower end opening between point A1, which is a left end point of the folded portion, and point A2, which is a right end point of the folded portion;
the bag inner boundary line of the lower end adhesive portion is a line connecting point B1, which is located on the bag inner side of point A1, and point B2, which is located on the bag inner side of point A2, and has a linear shape that is convex toward the opposing portion,
The self-standing bag has a connecting adhesive portion that is connected above the bottom adhesive portion and bonds the inner surfaces of the body film together,
The connecting adhesive portion is an area surrounded by point B1, point C1, which is the intersection of the folded portion or an extension of the folded portion and the left edge, and point D1, which is a point on the left edge and is above point C1, and an area surrounded by point B2, point C2, which is the intersection of the folded portion or an extension of the folded portion and the right edge, and point D2, which is a point on the right edge and is above point C2 ,
The bag inner boundary line of the bottom end adhesive portion is curved, and the points D1 and D2 are intersections of tangents at the points B1 and B2 with the left edge and the right edge, respectively; or
A self-standing bag characterized in that the bag inner boundary line of the lower end adhesive portion is straight, and the D1 point and the D2 point are intersections of an extension of the bag inner boundary line with the left edge and the right edge . a gap is present between the inner wall at the left end edge of the body portion and the left side of the bottom film and/or between the inner wall at the right end edge of the body portion and the right side of the bottom film, and the inner surfaces of the body films are bonded to each other in the gap;
The bottom adhesive portion further includes a left adhesive portion provided at a predetermined width from the left side edge and a right adhesive portion provided at a predetermined width from the right side edge,
point B1 is located on the inner side of the bag than point E1, which is a point on the folded-back portion of the bag inner boundary line of the left adhesive portion,
2. The self-standing bag according to claim 1, wherein point B2 is located on the inner side of point E2, which is a point on the folded portion of the inner boundary line of the bag at the right adhesive portion. When the distance between the point C1 and the point D1 and the distance between the point C2 and the point D2 are H1 and the total length of the left edge and the total length of the right edge are L1,
3. The self-standing bag according to claim 1, wherein the H1 is equal to or greater than 0.05L1 and equal to or less than 0.50L1. 4. The self-standing bag according to claim 1, wherein the body portion has a thick portion extending in the vertical direction of the body portion. The self-standing bag according to any one of claims 1 to 4, characterized in that the line connecting point B1 and point D1 and the line connecting point B2 and point D2 of the bag inner boundary line of the connected adhesive portion are convex outward from the bag. 6. The self-standing bag according to claim 1 , wherein the top opening of the body portion has a spout, a fitting, or a sealing seal. The self-standing bag further includes an additional adhesive portion connected to the connecting adhesive portion,
the additional adhesive portion is an area surrounded by point B1, point D1, and point F1 on the left edge which is above point D1, and an area surrounded by point B2, point D2, and point F2 on the right edge which is above point D2,
The self-standing bag according to any one of claims 1 to 6, characterized in that the distance between point B1 and point D1 is the same as the distance between point D1 and point F1, and the distance between point B2 and point D2 is the same as the distance between point D2 and point F2.