JP4231989B2 - Self-supporting bag and its manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a self-supporting bag provided with a closure portion, and more particularly to a self-supporting bag that is flexible and excellent in self-supporting property and excellent in attachment strength of the closure portion, and a method for manufacturing the self-supporting bag.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, self-supporting bags for fluids such as liquids are mainly used for refilling, and the self-supporting property has not been emphasized so much, and 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, the self-supporting bag for fluid may be provided with a closure for pouring out the contents, and in such a case, the upper part becomes heavy, and the lack of self-supporting property is remarkable. It was. In addition, a conventional self-supporting bag with a closure portion is formed by joining a predetermined portion of the peripheral portion of the bag body by heat welding, molding the closure portion separately, and placing the closure portion between sheets forming the bag body. The closure part was attached by inserting by work and heat-welding to the inner surface of the sheet. Such a manual operation not only affects the mass productivity, but also there is a fear that the thermal strength between the closure part and the sheet becomes insufficient, and the strength of the bag body becomes insufficient. On the other hand, the molded container, as a matter of course, has sufficient self-supporting property, but it cannot be reduced by being folded at the time of disposal.
[0003]
The present invention has been made in view of the above circumstances. When used, the function as a self-supporting bag is maintained until the contents are no longer used. It is another object of the present invention to provide a self-supporting bag excellent in manufacturing and a method for manufacturing a self-supporting bag suitable for manufacturing the self-supporting bag.
[0004]
[Means for Solving the Problems]
That is, the present invention is a self-supporting bag having a closure portion at the top of a bag body having a side film and a bottom film folded in an inverted V shape at the bottom, and at least the bottom film and the side film are fixed. From the upper end edge of the bag body to the both side edges, the lower end edge of the bag body and at least a part of the side edge where the bottom film exists are heat-welded. Provided is a self-standing bag characterized in that a substantially reverse-concave frame body integrally molded is attached to a side edge where the heat-welded portion is present, leaving a part or all of the heat-welded portion .
[0005]
Further, the present invention is a method for manufacturing the self-supporting bag, wherein at least a part of the lower end edge of the bag main body and at least the side end edge where the bottom film is present so that the bottom film and the side film are fixed. A method for manufacturing a self-supporting bag is provided, wherein the self-supporting bag is provided with a closure portion attached to the bag body so that the closure portion is integrated with the frame body after heat welding and joining.
[0006]
That is, the self-supporting bag of the present invention is a self-supporting bag provided with a closure portion at the top of a bag body having a side film and a bottom film folded in an inverted V shape at the bottom, and at least the bottom film and the side film. From the upper end edge of the bag body to the both side edges, which has a heat-welded portion where the lower end edge of the bag body and at least a part of the side edge where the bottom film exists are thermally welded, Since a substantially reverse-recessed frame body in which the closure part is integrally molded is attached, each side edge portion of the frame body becomes a so-called rib of the bag body and functions as a bag support, thereby Even if the bag body is provided with a closure portion at the top of the bag body, sufficient independence can be maintained until the contents are no longer present. And since the closure part is integrally molded with the said frame, it becomes what was excellent also in the attachment intensity | strength of the closure part, and various closures can be attached.
[0007]
In addition, although the said closure part may be integrally molded simultaneously with the shaping | molding of the said frame, what was shape | molded previously may be integrated by in-mold shaping | molding etc. at the time of frame shaping | molding. In addition to the side edge where the bottom film is present, the heat welded portion is provided at the side edge where the bottom film is not present, the lower edge, the lower corner (lower semicircular arc welded portion, etc.), etc. it can.
[0008]
Here, as will be described later, the frame of the present invention may be attached so as to extend from the upper end edge of the bag body to the entire length of both side edges. If the side edge where the part is present is attached with leaving part or all of the heat welded part, the self-supporting property is ensured by the expansion of the frame and the bottom film, and the resin used Less amount and light weight. In addition, the portion without the frame body is easy to fold and is easy to discard, which is more preferable.
[0009]
Further, if the frame body is attached so as to cover the outer surface of each edge of the bag body, it is possible to reinforce the bonding strength of the upper edge and both side edges of the bag body, which is more preferable. It is.
[0010]
In the self-supporting bag manufacturing method of the present invention, the film constituting the bag body is formed into a self-supporting bag shape, and at least the bottom film edge and the bottom film are present so that at least the bottom film and the side film are fixed. After a part of the side edge is thermally welded and joined, the bag is attached to the bag body so that the closure part is integrated with the frame body to form a self-supporting bag provided with the closure part. Therefore, in the present invention, when making a self-supporting bag, for example, only the bottom edge and the bottom edge of both side edges of the film are thermally welded so that only the bottom film and the side film of the bag body are fixed. Even if it is, it is possible to manufacture a self-supporting bag equipped with a closure by attaching the frame body and joining the unwelded portions of the upper end edge and both side edge edges of the bag body. Can be bagged. Moreover, even if it is a case where bags other than the lower side of the said side edge edge are made into the bag-shaped joint strength for the time being, it can reinforce joint strength by attaching the said frame. Therefore, the edge of a bag main body can be joined more easily and reliably. That is, the bag body may be completely bagged or incomplete as long as the bottom film is thermally welded, but by using a bag body that is more completely bagged, the present invention This self-supporting bag is excellent in strength, and the attachment of the closure and the frame becomes easier and more reliable, which is suitable as a method for manufacturing the self-supporting bag of the present invention.
[0011]
【The invention's effect】
Since the self-supporting bag of the present invention is flexible and excellent in self-supporting, when used, it functions as a packaging bag having self-supporting properties and satisfies the self-supporting properties until there is no content item even if it has a closure part. After use, it can be rounded to a small capacity and discarded, and the attachment strength of the closure is also excellent. It is also possible to reinforce the bonding strength. Therefore, the self-supporting 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 when discarded after use, and is suitable for environmental protection. Moreover, according to the manufacturing method of the self-supporting bag of the present invention, a self-supporting bag having the above-described characteristics and particularly excellent in strength as a packaging bag can be manufactured easily and reliably.
[0012]
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-supporting bag 1 for explaining a configuration example of the self-supporting bag of the present invention is inflated. The self-supporting bag 1 includes a closure portion 3 at the upper end portion of the bag body 2, and a substantially reverse concave frame 4 integrally formed with the closure portion 3 from one end edge 2 a to upper end edge 2 b to the other end edge 2 a. Each end edge 2a, 2b, 2a is attached so as to be sandwiched from the outside.
[0013]
The bag body 2 is formed by folding a long film into four folds so that it has side films 2c and 2c and a bottom film 2d folded in an inverted V shape at the bottom. The side edges 2a and 2a of the films 2c and 2c are joined together by thermal welding, and a part of the folded portion of the bottom film 2d is thermally welded in a substantially semicircular arc shape to form a lower substantially semicircular arc welded portion 2e and 2e. By forming the bottom surface 2f, the bottom surface 2f is formed. The bag body 2 is reinforced in bottom strength and self-supporting properties by the lower substantially semicircular arc welds 2e and 2e.
[0014]
As a film (side film 2c, 2c, bottom film 2d) which comprises the bag main body 2, a single layer or a multilayer film is used. These films may be the same as conventional films, but they do not necessarily have heat-welding properties, and when they are made into bags, they are bonded to the resin that is injected by the outer film surface. It is preferable that the property is good. The multilayer film is a co-extruded film, a laminate film, etc., and, for example, a gas barrier layer (EVOH, vinylidene chloride, ceramic vapor deposition, etc.) in order to give a necessary function to a stretched or unstretched polyolefin, nylon, polyester film or resin layer ) And co-extrusion type or laminate type films are preferably used.
[0015]
As the thickness of the film, 20 to 900 μm is applied, and a thick film is suitable from the standpoint of self-sustainability. However, a thin film is preferable from the viewpoint of flexibility and lightness, and the frame 4 is attached even if the film is thin. Independence can be ensured. In view of moldability and handleability, a desirable thickness is preferably 60 to 200 μm. The film is not limited to the one made of synthetic resin, and may be a single layer product or a laminate product of paper or metal foil.
[0016]
The shape and size of the closure part 3 are not particularly limited, and can be any shape and size according to the purpose of use of the packaging bag. Here, normally, the self-supporting bag with a closure part is manufactured by inserting the closure member into the upper end of the self-supporting bag by hand or by another operation using an automatic insertion machine and heat-sealing. In the case of a thick material, it is difficult to securely bond both ends of the closure member, and it is often difficult to perform the welding operation. However, in this invention, since it shape | molds so that it may integrate with the frame 4 so that it may mention later, such a difficulty is not accompanied.
[0017]
The frame body 4 is integrally formed with the closure portion 3 by, for example, injection molding or the like, or the closure portion 3 is first molded and molded integrally in a mold. There is no particular limitation as long as it is a resin that can be injection-molded and can be joined to the edge of the bag body 2, but in addition to polyethylene and polypropylene resins, which are general-purpose resins, injectable plastics such as nylon, polyester, various engineering Blends or copolymer resins of resins and elastomers can also be used.
[0018]
The frame 4 has a shape along the one side edge 2a to the upper edge 2b to the other edge 2a of the bag body 2 made of a resin film that has been molded in advance to have a predetermined self-standing bag shape. Here, the frame body in the self-supporting bag of the present invention may have such a length that the side edge portion extends over the entire length of the side edge as in the frame body 4 ′ shown in FIG. As in the case of the frame 4 shown in FIG. 1, even if the length is such that the lower portion of the side edge is left, a part of the folded portion of the bag body 2 is substantially semicircular as described above. Since the bottom strength and the self-supporting property are reinforced by the lower substantially semicircular arc welding parts 2e and 2e which are heat-welded in an arc shape and the heat-welding part of the side edge, the self-supporting property and strength as a bag intended by the present invention Is obtained.
[0019]
When the length of the part corresponding to the side edges 2a, 2a of the frame 4 is set to such a length that the lower part of the side edges 2a, 2a remains, the frame 4 The length of the corresponding portion is desirably 60% or more, particularly 80% or more of the entire length of the side edge. If it is too short, the effects of the present invention may not be sufficiently obtained. However, as will be described later, for example, when only the lower side is thermally welded so that the side edges 2a and 2a form the bottom surface 2f, the tip of the frame body is at least at the upper part of the heat welded portion. The length should be as long as possible, and the lower part should remain.
[0020]
The width and thickness of the frame body 4 are not particularly limited. For example, as in the frame body 4 shown in FIG. 1, the front end side of the portion corresponding to the side edge 2a, 2a (the lower side in the drawing). ) Is a tapered shape, the width is 1 to 20 mm, particularly 5 to 10 mm, and the thickness is 1 to 10 mm, particularly 2 to 5 mm, in a uniform width portion. Is preferred. In addition, when the whole is substantially uniform like 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, sufficient attachment strength to the bag body 2 may be difficult to obtain. If the thickness is too thick, the amount of resin used will increase, and from the viewpoint of disposal It is not preferable and if the width is too wide, it may be difficult to obtain a sufficient internal volume of the self-supporting bag.
[0021]
Next, one structural example of the manufacturing method of the self-supporting bag of this invention is demonstrated with reference to FIG.2 and FIG.3. FIG. 2 is a schematic front view of a self-standing bag made by the first step of the manufacturing method before attaching the frame body, and FIG. 3 is another configuration of the self-standing bag of the present invention obtained by the second step. It is a schematic front view of an example.
[0022]
A 1st process comprises the bag main body 2 using the normal self-supporting bag making machine so that it may become a self-supporting bag shape which has the side films 2c and 2c and the bottom film 2d folded in reverse V shape at the bottom part. The long film is folded so that the lower side is folded in four, and the lower edge, the one side edge 2a, and the other side edge 2a are joined by heat welding such as heat sealing or ultrasonic sealing, and the film is folded. The side films 2c and 2c and the bottom film 2d are fixed by joining the portions 2e and 2e of the left and right portions by means of heat welding or the like so as to form a substantially semicircular arc shape, and the upper end is as shown in FIG. The opened bag body 2 is made. In this step, a part of the upper end edge 2b of the bag body 2 can be thermally welded as long as the attachment property of the closure member is not impaired as will be described later.
[0023]
Here, the joining of the one side edge 2a and the other side edge 2a is performed 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 side of the edge 2a can be thermally welded, for example, in FIG. 2, the point where the one side edge 2a and the other side edge 2a intersect the line indicating the bottom surface 2f (base of the bottom film) It is excellent in strength when the self-supporting bag of the present invention is included. And it is also possible to heat weld only between about 2/5 of the total length of the side edge to the lower end of each side edge 2a, 2a (arrows 2g, 2g in FIG. 2). In particular, when the frame is not attached over the entire length of both side edges, such as the self-supporting bag shown in FIG. 1, the portions of the side edges where the frame is not attached should be heat-welded in advance. Cost. In addition, it is preferable that the lower substantially semicircular arc welded portions 2e and 2e formed for improving the self-supporting property are heat-welded in advance in consideration of workability.
[0024]
Moreover, even if it is a case where it joins over the full length of the one side edge 2a and the other side edge 2a, it does not require especially joining strength like the conventional self-supporting bag, for example, it becomes a bag shape for the time being. It may be a degree. However, even in this case, since the adhesive strength of the bottom portion may not be ensured with the frame alone (the stress of the bottom film film is most stressed by a self-supporting bag), at least the portion forming the bottom surface 2f, It is preferable to perform heat welding in advance with sufficient bonding strength. Further, when the frame does not extend over the entire length of the side edges as described above, it is preferable that the portions of the side edges where the frame is not attached are preliminarily heat-welded with sufficient bonding strength.
[0025]
In the case of the present invention, as described above, 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 are thermally welded, so that the alignment of the back surface film becomes easy, Even when the closure member and the frame can be integrally formed at an accurate position, or when a separately formed closure member is used, it can be formed integrally with the frame at an accurate position by a technique such as insert molding. .
[0026]
In the second step, the film constituting the bag body 2 obtained in the first step is set in a normal injection molding machine, and the closure part 3 is injected at a predetermined position on the upper end of the film constituting the bag body 2. At the same time as molding, the frame body 4 ′ is injection-molded so as to cover the outer surface (back surface) of the upper edge 2b and both side edges 2a, 2a of the film constituting the bag body 2 by the thermoplastic resin extending from the closure portion. The frame body 4 ′ is joined to the upper end edge 2b and the side end edges 2a, 2a of the bag body 2 to manufacture the self-supporting bag 1 ′ shown in FIG.
[0027]
The self-supporting bag is filled with contents (not shown) from the closure part to form a self-supporting shape with an expanded bottom surface, and after the closure part is sealed, it is stored and transported. In use, the contents can be discharged from the closure. There are no particular restrictions on the type of contents, and it can be used for a wide range of contents by appropriately selecting the type of film, closure material, etc. that make up the bag body. For example, a liquid, a viscous material, a powder, a small-diameter solid shape, or the like can be suitably accommodated. In this self-supporting bag, since both edge portions of the frame function as ribs, the self-supporting bag can maintain its self-supporting property until the contents disappear, and can be rounded down to be small when discarded. Therefore, according to the self-supporting bag of the present invention, a flexible container that can be replaced with a bottle, a bottle, a can and the like and can be fitted with various closures can be obtained.
[0028]
In addition, this invention is not restrict | limited to the said structure, For example, it does not provide a lower substantially semicircular arc welding part, but replaces with a simple linear lower end welding part or a lower substantially semicircular arc welding part. In addition to the linear lower end welded portion, an inclined 45 ° linear welded portion extending from the base of the bottom film is provided, and further, the bottom film uses a different one from the side film and does not depart from the gist of the present invention. Various changes can be made.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a self-supporting bag for explaining a configuration example of the self-supporting bag of the present invention.
FIG. 2 is a schematic front view of a bag body obtained by a first step for explaining a configuration example of a method for manufacturing a self-supporting bag according to the present invention.
FIG. 3 is a schematic front view of a self-supporting bag obtained by the second step of the manufacturing method.
[Brief description of symbols]
1, 1 'free standing bag 2 bag body 2a side edge 2b upper edge 2c side film 2d bottom film 3 closure part 4, 4' frame

Claims (3)

A self-supporting bag having a closure portion on the top of a bag body having a side film and a bottom film folded in an inverted V shape at the bottom, wherein at least the bottom film and the side film are fixed. Approximately the closure part is integrally molded from the upper end edge of the bag body to the both side edges, which has a heat-welded part where the lower end edge of the main body and at least a part of the side edge where the bottom film exists are heat-welded. A self-standing bag, wherein a reverse-concave frame is attached to a side edge where the heat-welded portion is present, leaving part or all of the heat-welded portion . It said frame body, according to claim 1 Symbol mounting self-supporting bag is attached so as to cover the outer surface of each edge of the bag body. A claim 1 or 2 method for producing a self-standing bag according, as at least a bottom film and side films are fixed, some of the existing side edges of the bottom edge and at least the bottom film of the bag body A method for manufacturing a self-supporting bag, wherein the self-supporting bag is provided with a closure portion attached to the bag body so that the closure portion is integrated with the frame body.

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