WO2003078264A1

WO2003078264A1 - Self-standing bag and method of manufacturing the bag

Info

Publication number: WO2003078264A1
Application number: PCT/JP2003/003225
Authority: WO
Inventors: Kazuhiro Ikeda; Takashi Shimizu
Original assignee: Fujimori Kogyo Co., Ltd.
Priority date: 2002-03-19
Filing date: 2003-03-18
Publication date: 2003-09-25
Also published as: AU2003236037A1; US20050141788A1; JP2003276741A; JP4231989B2

Abstract

A self-standing bag (1), comprising a bag body (2), a closure part (3), and a generally reverse-recessed frame body (4), wherein the closure part (3) is provided at the top part of the bag body (2) having two sheets of side films (2c, 2c) and a bottom film (2d) folded down on a bottom part in a reverse V-shape, and integrally formed with the generally reverse-recessed frame body (4) starting at the upper edge (2b) toward both side edges (2a, 2a) of the bag body (2) having a thermally fused part where the lower edge part of the bag body (2) and a part of the side edge having at least the bottom film (2d) are thermally fused to each other so that at least the bottom film (2d) can be fixed to the side films (2c, 2c).

Description

Specification

Self-standing bag and its manufacturing method

The present invention relates to a self-standing bag provided with a part of a closure, and more particularly to a self-standing bag which is flexible, has excellent self-supporting properties, and also has excellent attachment strength for a part of a closure, and a method of manufacturing the self-standing bag. About. Background art

Conventionally, self-supporting bags for liquids such as liquids are mainly used for refilling, and the self-sufficiency has not been given much weight.When the content decreases, the upper part of the bag bends and functions as a self-supporting bag. I didn't have it. In particular, self-supporting bags for fluids may have some closures for discharging contents, in which case the upper part becomes heavy and lacks self-reliance. Had become. A conventional free-standing bag with a part of the closure is formed by joining a predetermined portion of the peripheral part of the bag body by heat welding, and separately molding a part of the closure, thereby forming a closure between the sheets forming the bag body. Parts were manually inserted and heat-welded to the inner surface of the sheet to attach part of the closure. Such manual work not only affects the mass productivity, but also may cause insufficient heat welding between the closure and the sheet, resulting in insufficient strength of the bag body. On the other hand, molded containers, of course, have sufficient independence, but could not be folded down and made smaller. Disclosure of the invention

The present invention is a self-contained bag that retains its function as a self-contained bag when used, until the contents are exhausted, and when discarded, it can be folded down to reduce the capacity and also has excellent attachment strength for a part of the closure. It is another object of the present invention to provide a method for producing a self-standing bag suitable for producing the self-standing bag.

That is, the present invention is a self-standing bag having a closure part at the top of a bag body having two side films and a bottom film folded in an inverted V-shape at the bottom, At least a lower end edge of the bag body and a heat-welded portion having at least a part of a side edge where the bottom film is present so that the bottom film and the both side films are fixed. A self-contained bag characterized in that a substantially inverted concave frame body integrally formed with the closure portion is attached from the upper end edge to both side edges of the self-standing bag. In this case, the frame may be attached to the side edge where the heat-welded portion is present while leaving a part or the entirety of the heat-welded portion, or the outer surface of each edge of the bag body may be attached. It is more preferable that it is attached so as to cover it. The present invention also relates to the method for producing a self-standing bag, wherein at least a bottom edge of the bag main body and at least a side edge where the bottom film exists so that the bottom film and the two side films are fixed. After the parts are heat-welded and joined, the frame is attached to the bag body so that the closure portion is integrated with the frame to form a self-standing bag having a closure portion. A method for producing a self-standing bag is provided. The self-standing bag of the present invention is a self-standing bag having a closure portion at the top of a bag body having two side films and a bottom film folded in an inverted V shape at the bottom, and at least the bottom surface Upper end of the bag body having a heat-welded portion in which the lower edge of the bag body and at least a part of the side edge where the bottom film is present are heat-welded so that a film and the films on both sides are fixed. From the edge to both side edges, a substantially inverted concave frame body in which a part of the closure is integrally molded is attached, so that a portion of the frame body on each side edge of the bag main body is a so-called rib of the bag body. By functioning as a support for the bag, the self-sustainability of the bag body is improved, and even if the bag body has a closure at the top, sufficient self-sustainability can be maintained until the contents are exhausted. . And since the closure is partly formed integrally with the frame, the attachment strength of the closure is also excellent. Also, various closures can be easily and securely attached.

A part of the closure may be integrally molded with the frame at the same time as the molding of the frame. However, a pre-molded one is used. May be used. In addition, the heat-welded portion is provided at the side edge where the bottom film is present, the side edge where the bottom film is not present, the lower edge, the lower corner (the lower substantially semi-circular welded portion, etc.). Can be. Here, as will be described later, the frame of the present invention may be attached so as to extend from the upper edge of the bag body to the entire length of both side edges. If the heat-sealed part is attached to the side edge where the part is present, part or all of the heat-welded part is left, the independence is secured by the expansion of the frame and the bottom film, and the frame is The amount of resin used for molding is small and light. In addition, a portion without a frame is more suitable because it can be easily folded and discarded.

Further, when the frame body is attached so as to cover the outer surface of each edge of the bag body, the joining strength of the upper edge and both side edges of the bag body can be reinforced. It is suitable.

The method for producing a self-supporting bag according to the present invention is characterized in that a film constituting the bag main body has a self-standing bag shape, and a lower edge and at least a bottom surface of the bag main body are fixed so that at least a bottom film and two side films are fixed. After joining a part of the side edge where the film is present by heat welding, it is attached to the bag body so that a part of the closure is integrated with the frame to make a self-standing bag with a closure part. Things. Therefore, in the present invention, when making a self-standing bag, only the lower edge of the film or the like and the lower side of both side edges are fixed so that, for example, only the bottom film and the side film of the bag body are fixed. Even when heat-welded, when attaching the above-mentioned frame body, the frame body joins the unwelded end portions of the bag body and the unwelded portions of both side edges, thereby closing the bag body. A self-standing bag with one can be made. In addition, even if the bag is made with a bonding strength such that the portion other than the lower side of the side edge is temporarily formed into a bag shape, the bonding strength is reinforced by attaching the frame. Therefore, the edges of the bag body can be more easily and reliably joined. That is, if the bottom film is heat-sealed, the bag body may be completely made or may be incomplete. The self-standing bag of the present invention has excellent strength, and the attachment of the closure and the frame is easier and more reliable, and is suitable as a method for producing the self-standing bag of the present invention.

Here, the formation of the frame, attachment to the bag body, and joining are preferably performed by injection molding of a resin. It is preferable that a part of the closure is integrally joined.

Since the self-supporting bag of the present invention is flexible and also excellent in self-sustainability, it functions as a self-supporting packaging bag when used, and satisfies self-sustainability even if a part of the closure is provided until the contents are exhausted. However, after use, it can be rolled up and discarded in a small capacity, and it also has excellent attachment strength for a part of the closure. It is also possible to reinforce the joint strength. Therefore, the self-standing bag of the present invention is easy to use at the time of use, has excellent strength as a packaging bag, can be easily reduced in volume at the time of disposal after use, and is suitable for environmental protection. Further, according to the method for producing a self-supporting bag of the present invention, a self-standing bag having the above-described characteristics and particularly excellent in strength as a packaging bag can be easily and reliably manufactured. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic perspective view of a self-standing bag illustrating one configuration example of the self-standing bag of the present invention. FIG. 2 is a schematic front view of a bag main body obtained in a first step for explaining one configuration example of the method for producing a self-standing bag of the present invention.

FIG. 3 is a schematic front view of the self-standing bag obtained in the second step of the above manufacturing method. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic perspective view showing a state in which a self-standing bag 1 is inflated, which explains one configuration example of a self-standing bag of the present invention. The self-standing bag 1 is provided with a closure portion 3 at the upper end of the bag body 2, and is formed substantially integrally with the closure part 3 from one side edge 2a to the upper edge 2b to the other side end 2a. A concave frame 4 is attached so as to sandwich each edge 2a, 2b, 2a from the outside. The bag body 2 is formed by folding a long film into four so that it has two side films 2c, 2c and a bottom film 2d folded in an inverted V-shape at the bottom. As will be described later, the side edges 2a, 2a of the two side films 2c, 2c are joined by heat welding, and a part of the folded portion of the bottom film 2d is substantially semicircular. The lower semi-circular welds 2 e and 2 e are formed by arc welding. Thus, the bottom surface 2 f is formed. In addition, the bottom body and the self-sustainability of the bag body 2 are reinforced by lower substantially semi-circular welded portions 2e and 2e.

As the film constituting the bag body 2 (side film 2c, 2c, bottom film 2d), a single-layer or multilayer film is used. These films may be the same as conventional films, but they do not necessarily need to have heat-sealing properties.When made into a bag, the film surface on the outer surface forms a frame. It is preferable that the adhesiveness to the resin to be injected to the surface is good. The multilayer film is a co-extruded film, a laminate film, or the like. In order to impart a necessary function to a stretched or unstretched polyolefin, nylon, polyester film or resin layer, for example, a gas barrier layer (EV OH, chloride) Co-extrusion type with vinylidene, ceramic vapor deposition, etc.) or a film of a laminate type thereof are preferably used.

A thickness of 20 to 900 m is applied as the thickness of the film.Thick films are suitable for independence, but thin films are preferable for flexibility and lightness, and even thin films By attaching the frame 4, independence can be secured. From the viewpoint of moldability and handleability, a desirable thickness is preferably from 60 to 200 m. The film is not limited to a synthetic resin film, but may be a single-layer product or a laminated product of paper or metal foil.

The shape and size of the closure part 3 are not particularly limited, and may be any shape and size according to the intended use of the packaging bag. Here, the self-supporting bag with a part of the closure is usually manufactured by inserting a closure member into the upper end of the self-standing bag body by hand or by another operation using an automatic insertion machine and heat-sealing the part. When the thickness of the material is large, it is difficult to securely adhere the closure member to the part of the closure at the upper end of the self-standing bag main body and the entrance, which often causes difficulties in welding work. However, in the present invention, since the closure part 3 is molded so as to be integral with the frame 4 as described later, such difficulty does not occur.

The frame 4 is integrally molded with the closure part 3 simultaneously by, for example, injection molding, or the closure part 3 is molded first and then integrally molded with the closure part 3 in a mold. It is. These resins are not particularly limited as long as they can be injection-molded and can be joined to the edge of the bag body 2, but are generally used resins such as polyethylene and polyethylene. In addition to propylene resin, injectable plastics such as nylon, polyester, various engineering resins, blends or copolymers of these resins with elastomers and the like can also be used.

The frame 4 has a shape along one side edge 2a to the upper edge 2b to the other side edge 2a of a bag body 2 made of a resin film molded in advance into a predetermined self-standing bag shape. Have. Here, the frame in the self-standing bag of the present invention may have a length such that the side edge extends over the entire length of the side edge as in a frame 4 'shown in FIG. Also, as in the frame 4 shown in FIG. 1, even if the length is such that the lower part of the side edge is left, a part of the portion where the film of the bag body 2 is folded as described above is used. The bottom part strength and independence are reinforced by the lower substantially semi-circular welds 2 e and 2 e, which are heat-welded in substantially semi-arcs, and the heat-welded parts at the side edges. Independence and strength as a bag can be obtained. When the length of the portion corresponding to the side edges 2a, 2a of the frame body 4 is set to such a length that the lower portion of the side edges 2a, 2a remains, the frame The length of the corresponding portion of the body 4 is preferably at least 60%, more preferably at least 80% of the total length of the side edge. If the length is too short, the effect of the present invention may not be sufficiently obtained. However, as will be described later, for example, when only the lower side is heat-welded so that the side edges 2a, 2a form the bottom surface 2f, at least the upper part of the heat-welded portion is a frame body. The length should be such that the tip of the head reaches, and the lower part should remain.

The width and thickness of the frame 4 are not particularly limited. For example, as shown in FIG. 1, the frame 4 shown in FIG. If the lower side of the drawing is tapered, the width is 1 to 20 mm, especially 5 to: L 0 mm, and the thickness:! It is preferable that the shape is set to be about 10 mm, particularly 2 to 5 mm. In addition, when the whole is substantially uniform as in the frame 4 ′ shown in FIG. 3, it is preferable that the average width and the average thickness are within the above ranges. If the width is too narrow or the thickness is too thin, it may be difficult to obtain sufficient mounting strength to the bag body 2.If the thickness is too thick, the amount of resin used increases, and the viewpoint of disposability If the width is too wide, it may be difficult to obtain a sufficient internal volume of the self-standing bag.

Next, one configuration example of the method for producing a self-standing bag of the present invention will be described with reference to FIGS. 2 and 3. FIG. Fig. 2 is a schematic view of the self-standing bag made in the first step before attaching the frame. FIG. 3 is a schematic front view of another configuration example of the self-standing bag of the present invention obtained in the second step.

In the first step, using a normal self-standing bag making machine, the bag body is formed into a self-standing bag shape having side films 2c, 2c and a bottom film 2d folded into an inverted V-shape at the bottom. Fold the long film that constitutes 2 so that the lower side folds into four, and join the lower edge and one side edge 2a and the other side edge 2a by heat welding such as heat sealing or ultrasonic sealing. At the same time, the side films 2c, 2c, and the bottom film 2d are fixed by joining the portions 2e and 2e of the folded portion of the film by means such as heat welding so as to form a substantially semicircular arc. Then, as shown in FIG. 2, a bag body 2 having an open upper end is made. In this step, a part of the upper edge 2b of the bag body 2 can be heat-welded as long as the attachment of the closure member is not impaired as described later.

Here, one side edge 2a and the other side edge 2a are joined together as long as the side films 2c and 2c and the bottom film 2d are fixed and the bottom surface 2f is formed. Although only the lower end of the side edge 2a and the other side edge 2a can be heat-welded, the heat-welded portion is, for example, one side edge 2a and the other side edge 2 in FIG. It is preferable that a contains a point (the base of the bottom film) that intersects the line indicating the bottom surface 2f because the strength of the self-standing bag of the present invention is excellent. In this case, it is also possible to heat-weld only the part from the upper side of the total length of the side edge by about 25 to the lower end of each side edge 2a, 2a (arrows 2g, 2g in Fig. 2). it can. In particular, when the frame is not attached over the entire length of both side edges, for example, as in the case of a self-standing bag shown in Fig. 1, the portions of both side edges where the frame is not attached must be heat-sealed in advance. I need to put it. It is desirable that the lower substantially semi-circular welds 2e and 2e formed for improving the self-sustainability are heat-welded in advance in consideration of workability.

Also, even in the case of joining along the entire length of one side edge 2a and the other side edge 2a, the joining strength is not particularly required as in a conventional free-standing bag. It may be about the degree. However, even in this case, it may not be possible to ensure the adhesive strength at the bottom of the frame alone (the base of the bottom film is the most stressed in a self-supporting bag). About It is preferable to heat-weld with sufficient bonding strength. When the frame does not extend over the entire length of both side edges as described above, portions of the side edges to which the frame is not attached should be heat-welded with sufficient bonding strength in advance. preferable.

In the case of the present invention, since at least a part of the side edge and the lower edge of the film folded so that at least the bottom surface is formed as described above are heat-welded, the alignment of the back surface film becomes easy, Even if the closure member and the frame can be integrally molded at an accurate position, or if a separately molded closure is used, the frame can be integrated with the frame at the correct position by insert molding. Can be molded.

In the second step, the film constituting the bag body 2 obtained in the first step is set in a usual injection molding machine, and the closure 3 is placed at a predetermined position at the upper end of the film constituting the bag body 2. At the same time as injection molding, the thermoplastic resin extending from a part of the closure is used to cover the outer surface (back surface) of the upper edge 2b, both side edges 2a, and 2a of the film constituting the bag body 2. The body 4 ′ is injection molded, and the frame body 4 ′ is joined to the upper end edge 2 b and both side edges 2 a, 2 a of the bag body 2 to produce the self-standing bag 1 ′ shown in FIG.

The self-standing bag is filled with contents (not shown) from a part of the closure, and has a free-standing shape with a widened bottom. After sealing the closure, it is stored and transported. In use, the contents can be discharged from a part of the closure. The type of contents is not particularly limited, and it is possible to handle a wide range of contents by appropriately selecting the type of material, such as the film constituting the bag body and a part of the closure. It is preferable to have, for example, a liquid, a viscous material, a powder, and a small-diameter solid shape. This self-standing bag can maintain its self-sustainability until the contents are exhausted, since both side edges of the frame function as ribs, and can be rolled up and made small when discarded. Therefore, according to the self-standing bag of the present invention, it is possible to obtain a flexible container that can be replaced with a bottle, a bottle, a can, and the like, and that can be fitted with various closures.

In addition, the present invention is not limited to the above configuration. In place of the arc-shaped welded part, in addition to the linear lower-end welded part, a 45-degree linear welded part extending from the base of the bottom film shall be provided. Various changes may be made without departing from the spirit of the invention.

Also, some closures can be selected in various ways. For example, a cap that can be sealed with a screw or a cap that can be opened and closed with a hinge may be added, or a closure section provided with a nozzle for sucking and taking out contents may be used.

Furthermore, as long as the shape outside the bag itself does not impair the function of being self-supporting due to the open bottom, it can be made into variously designed deformed bags.

Claims

The scope of the claims

1. A self-supporting bag having a closure part at the top of a bag body having two side films and a bottom film folded into an inverted V-shape at the bottom, wherein at least the bottom film and the both side films The lower end edge of the bag body and at least a part of the side edge where the bottom film is present have a heat-welded portion to which the bottom film is heat-welded. A self-contained bag, characterized in that a substantially inverted concave frame body integrally formed with the mouth-and-jar portion is mounted.

2. The self-standing bag according to claim 1, wherein the frame is attached to a side edge where the heat-welded portion is present, leaving a part or all of the heat-welded portion.

3. The self-standing bag according to claim 1, wherein the frame is attached so as to cover an outer surface of each edge of the bag body.

4. The method for manufacturing a self-standing bag according to claim 1, 2, or 3, wherein the bag body is fixed so that at least a bottom film and two side films are fixed. After the lower edge and at least a part of the side edge where the bottom film is present are joined by heat welding, the frame is attached to the bag body so that a part of the closure is integrated with the frame. A method for producing a self-standing bag, wherein the self-standing bag is partially provided.