WO2003057580A1

WO2003057580A1 - Self-standing bag and method of manufacturing the bag

Info

Publication number: WO2003057580A1
Application number: PCT/JP2002/013587
Authority: WO
Inventors: Kazuhiro Ikeda; Yoshimi Usami; Takaaki Katsuhara
Original assignee: Fujimori Kogyo Co., Ltd.; Mitani Sangyo Co., Ltd.; Act-T Corporation
Priority date: 2001-12-28
Filing date: 2002-12-26
Publication date: 2003-07-17
Also published as: JP2003191964A; JP3952145B2; AU2002357514A1; US20050053314A1

Abstract

A self-standing bag (1) having a closure part (3) on a bag body (2), characterized in that both end edges (2a, 2a) and the upper end edges (2b) of the bag body (2) are connected to each other by end edge connection parts (4) of thermoplastic resin covering the outer surfaces of the end edges, and the closure part (3) is formed integrally with the end edge connection parts (4).

Description

Specification

Self-standing bag and its manufacturing method

The present invention relates to a self-supporting 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 the closure. Background art

Conventionally, self-standing bags for liquids such as liquids are mainly used for refilling, and the self-sufficiency has not been given much weight.For example, if the content is reduced to about 13 or less, the upper part of the bag will bend, It no longer functions as a self-supporting bag. In particular, self-supporting bags for fluids may have some closures for pouring out contents, in which case the upper part becomes heavy and lacks self-reliance. I was In a conventional free-standing bag with a part of the closure, a peripheral part of the bag body is joined by heat welding, and a part of the closure is separately formed, and a closure part is formed between sheets forming the bag body. Part of the closure was attached by manual insertion and heat welding to the inner surface of the sheet. Such manual work not only affects mass productivity, but also may result in insufficient heat welding between the closure and the sheet, resulting in insufficient strength of the bag body. On the other hand, molded containers naturally have sufficient independence, but could not be folded or discarded when discarded.

Disclosure of the invention

The present invention has been made in view of the above circumstances, and when used, retains the function as a self-standing bag until the contents are exhausted, and when discarded, it can be folded down to reduce the capacity, as well as a part of the closure. It is an object of the present invention to provide a self-standing bag excellent in mounting strength and a method of manufacturing a self-standing bag suitable for manufacturing the self-standing bag.

That is, the present invention is a self-standing bag provided with a closure portion at the top of the bag body, wherein both side edges and the upper edge of the bag body are made of a thermoplastic resin which covers the outer surfaces of these edges. A self-standing bag, wherein the self-standing bag is joined by an edge joining portion, and a part of the closure is formed integrally with the edge joining portion. Here, it is more preferable that the edge joining portion of the bag body and the closure portion are formed by injection molding.

Further, the present invention relates to the method for producing a self-standing bag, wherein when forming the edge joining portion of the bag body, a cavity is formed at an edge of the bag body, and a thermoplastic resin is applied to the cavity. The present invention provides a method for manufacturing a self-standing bag, wherein an edge is joined by injecting and joining the edges of the bag body. Here, when forming the edge joining portion of the bag main body, a die which is substantially half-shaped of the edge joining portion is formed on one surface side of the edge of the bag main body by a die slide injection method, A thermoplastic resin is injected into the cavity to form a substantially half body of the edge joint, and then a cavity is formed on the other side of the edge of the bag body so as to have the remaining shape of the edge joint. It is more preferable that the thermoplastic resin is injected into the cavity to mold the remaining portion of the edge joining portion, and that the edge of the bag body be joined to form the edge joining portion.

That is, in the self-standing bag of the present invention, since the upper end edge and both side edges of the bag body are joined by the edge joining portion made of a thermoplastic resin covering the outer surface of these edges, the edge joining of each side edge is performed. The part becomes the so-called rib of the bag body and functions as a support for the bag, thereby improving the independence of the bag body. Even if a part of the closure is provided at the top of the bag body, sufficient independence until the contents are exhausted Sex can be maintained. And since the closure part is integrally formed with the above-mentioned edge joint part, the attachment strength of a part of the closure is also excellent.

Here, if the edge joining portion and the closure portion of the bag body are formed by injection molding, the edge joining portion can be easily and reliably formed by, for example, a die slide injection method. Since it is possible to form and simultaneously mold the closure part, it is more preferable.

In the method for producing a self-standing bag according to the present invention, when forming an edge joint portion of the bag body, a cavity is formed at an edge of the bag body, and a thermoplastic resin is injected into the cavity to form the bag body. A method for producing a self-supporting bag, characterized in that an edge joining portion is formed by joining edges of the self-standing bag. For example, forming the edge joining portion of the bag body of the self-standing bag At this time, a cavity is formed on the one side of the edge of the bag body by a die slide injection method so as to be a substantially half shape of the edge joint, and a thermoplastic resin is injected into the cavity to form the edge joint. A substantially half body is molded, and then a cavity is formed on the other surface so as to form the remaining portion of the edge joining portion. A thermoplastic resin is injected into the cavity to mold the remaining portion of the edge joining portion. This is a manufacturing method for forming an edge joint by joining the edges of the bag body. By adopting such a method, for example, the thermoplastic resin is injected so as to cover the outer surface of the end portion of the bag body placed in the mold in a state where the sheets are overlapped, by injection molding performed in one step. When the outer surface of the edge of the bag body is covered with thermoplastic resin, the edge of the bag body can be reliably located at the center of the resin (the center of the joint) as compared with the case where the edge joint is formed. Therefore, it is preferable because the edges of the bag body can be more easily and reliably 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. Therefore, the self-standing bag of the present invention is easy to use at the time of use, can easily reduce the volume at the time of disposal after use, and is adapted to environmental protection. Further, according to the method for manufacturing a self-standing bag of the present invention, a self-standing bag having the above-described characteristics and having particularly excellent bonding strength of the bag body 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 the self-standing bag.

FIG. 3 is a schematic diagram of an injection mold explaining one configuration example of a method for manufacturing a self-standing bag of the present invention.

FIG. 4 is a schematic diagram of the above injection mold.

FIG. 5 is a schematic partial view of the injection mold.

FIG. 6 is another schematic partial view of the injection mold. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail with reference to the drawings. 1 and 2 illustrate an example of the configuration of the self-standing bag of the present invention. FIG. 1 is a schematic perspective view showing a state where the self-standing bag 1 is inflated. 1 is a schematic front view showing a state in which a self-standing bag 1 is folded. The self-standing bag 1 has a closure part 3 at the upper end of the bag body 2 and folds so that the lower side of the long film constituting the bag body 2 is folded into four parts. A bottom surface 2c is formed by joining a to the upper edge 2b to the other edge 2a.

As the bag body 2, a single-layer or multilayer film is used. These films do not necessarily have to have heat-sealing properties like conventional films, but when formed into a bag, the film surface on the outer surface side is infused with resin to be injected to form an edge joint. Preferably, the adhesion is good. The multilayer film is a co-extruded film, a laminated film, or the like. In order to add a necessary function to a stretched or unstretched polyolefin, nylon, polyester film or resin layer, for example, a gas barrier layer (EVOH, Saran, ceramic vapor deposition) is used. And the like, or a co-extrusion type film or a laminate type film thereof is preferably used.

As the thickness of the film, 20 to 900 m is applied.Thick film is suitable for self-sustainability, but even for thin film for flexibility and light weight, The independence can be secured by providing. From the viewpoint of moldability and handleability, a desirable thickness is preferably 100 to 200 m. The film is not limited to a synthetic resin film, but may be a single-layer product or a laminate 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 the closure member into the upper end of the self-standing bag by hand or by another operation using an automatic insertion machine and heat-welding the closure member. If the thickness is large, it is difficult to securely bond both ends of the closure member, and welding work is often difficult. However, in the present invention, such a difficulty does not occur because the injection molding is performed integrally with the edge joining portion 4 as described later. The edge joint 4 is integrally molded with the closure part 3 simultaneously by injection molding, or The part 3 of the closure is molded first and then integrally molded in a mold. These forming resins are resins that can be injection-molded and that can join the edges of the bag body 2. Although there is no particular limitation, injectable plastics such as general-purpose resins such as polyethylene and polypropylene resins, for example, blends or copolymer resins of nylon, polyester, various engineering resins, elastomers, etc. can also be used. is there.

The edge joining portion 4 is formed along a side of one side 緣 2 a to an upper end 2 b to another side 緣 2 a of the bag main body 2 made of a resin film molded in a predetermined self-standing bag shape. The width and thickness are not particularly limited, but the width (arrow w in FIG. 1) is 1 to 20 mm, especially 5 to: L 0 mm, and the thickness (in FIG. 1). The arrow d) is preferably formed to have a length of l to 10 mm, particularly 2 to 5 mm. If the width is too narrow or too thin, it may be difficult to obtain sufficient bonding strength.If the thickness is too thick, the amount of resin used increases, which is not preferable from the viewpoint of disposability, and the width is If it is too wide, it may be difficult to obtain a sufficient internal volume of the self-supporting bag.

The method for producing the self-standing bag 1 is not particularly limited, but as shown in FIGS. 3 and 4, a substantially half body of the edge joining portion is provided on one side of the edge of the bag body, The first mold 5, which is formed by the upper mold 5a and the lower mold 5b, forms a cavity that forms a part of the closure at a predetermined position of the upper end of the bag. A second mold 6 is provided for forming the cavity forming the remainder with the upper mold 6a and the lower mold 6b. The upper molds 5a, 6a are provided with filling ports 7, 7, respectively. 5, a die slide injection system having a structure in which the second mold 6 slides, using an injection molding machine A capable of in-mold molding and insert molding, and having a predetermined self-standing bag shape in advance. It is preferable that the resin film 2 ′ molded and folded as described below is manufactured as follows. You.

First, as shown in FIG. 3, the resin film 2 ′ is set on the lower mold 5 b of the first mold 5, and then the upper mold 5 a is lowered, and the upper end of the resin film 2 ′ bag body and Insert the tapered tip 8a of the slide core 8 for partially forming the closure between the films on the one end 2'a side, and cut the four-folded part of the other end 2'b forming the bottom of the bag body. Set one piece. Set in this way and remove the lower edge By injecting the resin into the edge, a bottom surface that can be expanded is formed. Specifically, as the upper mold 5a descends, it faces one end 2'a of the resin film 2 'and both side ends (not shown), and as shown in FIG. A cavity 9a is formed on one surface side of the portion to be the side wall peripheral portion, the cavity 9a being a substantially half shape of the edge joining portion. The thermoplastic resin melted and softened by the filling port 7 provided in the upper mold 5a, the eject mechanism (not shown) provided in the lower mold 5b, and the vacuuming mechanism connected to the cavities 5b. Injecting into the cavity of the bag, a part of the closure is molded at a predetermined position on the upper end of the bag body, and at the same time, the thermoplastic resin extending from the part of the closure causes the resin film 2 ′ as shown in FIG. On the one side of the upper edge, both side edges of the bag body of the above, the approximately half body 4a of the edge joint is primarily molded, and then the second mold 6 is slid. As shown in the figure, the thermoplastic resin is injected into the cavity 9b of the second mold 6, and the remaining portion 4b of the edge joining portion is secondarily molded on the other surface side of the above-described portion, and the upper edge of the bag body is formed. By joining the portions that will be the both ends, an edge joint 4 is formed, Manufacture self-standing bags.

Here, as described above, when the edge joining portion 4 is formed in two steps, the end of the resin film 2 ′ folded so as to have a bag body shape is injected into the cavity by the thermoplastic resin. This prevents the overlapping film ends from opening and the film ends from being distorted in one direction with the film ends overlapping. It can be joined while sandwiched between the parts. The self-standing bag is filled with contents (not shown) from a part of the closure to form a self-supporting shape with a widened bottom. After sealing the part of the closure, it is stored and transported. In use, the contents can be discharged from a part of the closure. The type of the contents is not particularly limited, but those having fluidity are suitable, and for example, liquids, viscous materials, powders, small-diameter granular materials, and the like can be suitably accommodated. Since the self-standing bag functions as a rib at the edge joints on both sides, the self-supporting bag can maintain its independence until the contents are exhausted, and can be rolled up and made small when discarded.

The present invention is not limited to the above configuration, and may be variously modified without departing from the gist of the present invention. For example, depending on conditions such as the moldability of the resin of the film and the like, the molding may be performed in one step, or instead of sliding the die as described above, a slidable pin is provided in a mold, and this pin is provided. Injection is performed halfway while holding the bag body so that the edge of the bag body is located at the center of the edge joint. In addition to filling the gaps, the edge joints can be molded to a predetermined thickness and fixed after joining.

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

Furthermore, as long as the shape of the bag body does not impair the function of being self-supporting by opening the bottom, variously designed deformed bags can be obtained.

Claims

The scope of the claims

1. A self-supporting bag with a closure part at the top of the bag body, with both side edges and top edge of the bag body joined by edge joints made of thermoplastic resin covering the outer surfaces of these edges. And a part of the closure is formed integrally with the edge joining portion.

2. The self-standing bag according to claim 1, wherein the edge joint portion of the bag body and a part of the closure are formed by injection molding.

3. The method for producing a self-standing bag according to claim 1, wherein a cavity is formed at an edge of the bag body when forming an edge joint portion of the bag body, and a thermoplastic resin is applied to the cavity. A method for producing a self-standing bag, comprising forming an edge joint by injecting and joining the edges of the bag body.

4. The method for producing a self-standing bag according to claim 1, wherein, when forming an edge joint of the bag body, an edge joint is formed on one side of an edge of the bag body by a die slide injection method. A half-shaped cavity is formed, and a thermoplastic resin is injected into the cavity to form a substantially half body of an edge joint, and then the edge is joined to the other side of the edge of the bag body. By forming a cavity having the remaining shape of the portion, injecting a thermoplastic resin into the cavity to mold the remaining portion of the edge joining portion, and joining the edge of the bag body, the edge joining portion is formed. A method for producing a self-standing bag, characterized by being formed.