JP2003276741A - Self-supportable bag and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-supportable bag which functions as a self-supportable packaging bag in use since the bag shows excellent self-supportability in spite of its flexibility, satisfies its self-supportability until the content is used up even if it has a closure portion, and which can be small-sized for disposal after use and shows excellent attachment strength of the closure portion. <P>SOLUTION: The self-supportable bag 1 is equipped with the closure portion 3 arranged on the upper portion of the bag main body 2 having side surface films 2c and 2c and a bottom surface film 2d folded in a reverse V-letter shape in the bottom portion and an approximately reverse concave frame 4 having the closure portion 3 formed into one body is attached to a portion from the upper edge margin 2b to both the side edge margins 2a and 2a of the bag main body 2 having a hot melt-bonded portion formed by hot melt-bonding the lower edge margin of the bag main body 2 and at least a part of the side edge margin where the bottom surface film 2d exists so that at least the bottom surface film 2d is fixed to the side surface films 2c and 2c. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-supporting bag having a closure portion, and more particularly, a self-supporting bag which is flexible and has excellent self-supporting property and attachment strength of the closure portion. Manufacturing method.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
Self-standing bags for fluids such as liquids are mainly used for refilling, the self-supporting property is not so important, and when the number of contents decreases, the upper part of the bag bends and does not function as a self-supporting bag. Was there. In particular, a self-supporting bag for fluid may be provided with a closure part for pouring out contents, and in such a case, the upper part becomes heavy, and lack of self-supporting property becomes remarkable. It was Further, the conventional self-standing bag with a closure part is formed by joining a predetermined part of the peripheral portion of the bag body by heat welding, and molding the closure part separately from it.
The closure part was attached by manually inserting the closure part between the sheets forming the bag body and heat-sealing the inner surface of the seat. Such manual work not only affects mass productivity, but also causes insufficient heat welding between the closure portion and the sheet, which may result in insufficient strength of the bag body. On the other hand, the molded container naturally has sufficient self-supporting property, but could not be folded and made small at the time of disposal.

The present invention has been made in view of the above circumstances. When used, the function as a self-standing bag is retained until the contents are exhausted, and at the time of disposal, it can be folded to reduce the capacity and the closure portion. It is an object of the present invention to provide a self-supporting bag having excellent attachment strength and a method for manufacturing the self-supporting bag suitable for manufacturing the self-supporting bag.

[0004]

That is, the present invention is a self-supporting bag having a closure part on the upper part of a bag body having a side film and a bottom film that is folded in an inverted V shape at the bottom, and at least the above-mentioned. From the upper edge of the bag body having a heat-welded portion in which a bottom 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 the bottom film and the side film are fixed. There is provided a self-supporting bag having a substantially inverted concave frame body integrally formed with the closure part, which is attached to both side edges. Here, the frame body is attached to the side edge where the heat-welded portion is present, leaving a part or all of the heat-welded portion, or covers the outer surface of each edge of the bag body. It is more preferable that it is attached as described above.

The present invention is also the method for manufacturing the above-mentioned self-supporting bag, wherein at least the bottom edge of the bag body and the side edge where the bottom film is present are fixed so that at least the bottom film and the side film are fixed. A method for manufacturing a self-supporting bag, characterized in that after the parts are heat-welded and joined together, the closure part is attached to the bag body so that the closure part is integrated with the frame body to form a self-supporting bag having a closure part. provide.

That is, the self-supporting bag of the present invention is a self-supporting bag having a closure part on the top of the bag body having a side film and a bottom film that is folded in an inverted V shape at the bottom, and at least the bottom film. The bottom 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 so that the side film is fixed to the top edge of the bag body and both side edges. Since a substantially reverse concave type frame body in which the closure part is integrally molded is attached, the side edge portions of the frame body become so-called ribs of the bag body, and by functioning as the support pillars of the bag, In addition, it is possible to improve the self-supporting property of the bag body and maintain the self-supporting property until the contents are exhausted even when the bag body is provided with the closure part. Further, since the closure part is integrally molded with the frame body, the attachment strength of the closure part is also excellent, and various closures can be attached.

The closure portion may be integrally molded at the same time as the molding of the frame body, but a previously molded product may be integrally molded by in-mold molding or the like. In addition to the side edge where the bottom film is present, the heat-welding portion may be provided at the side edge where the bottom film is not present, the lower edge, the lower corner (such as the lower semi-circular arc weld). it can.

Here, the frame body of the present invention may be attached so as to extend over the entire length from the upper end edge of the bag body to both side edge edges thereof, as will be described later.
When it is attached with part or all of the heat-welded portion left on the side edge where the heat-welded portion is present, self-supporting property is ensured by expanding the frame and the bottom film, and is used. A small amount of resin is required, resulting in a light weight. In addition, the part without the frame is easy to fold and easy to discard, which is more preferable.

If the frame body is attached so as to cover the outer surface of each end edge of the bag body, it is possible to reinforce the joint strength of the upper end edge and both end edges of the bag body. , More preferred.

In the method for producing a self-supporting bag of the present invention, the film forming the bag body is formed into a self-supporting bag shape, and the lower end edge of the bag body and at least the bottom film are fixed so that at least the bottom film and the side film are fixed. Is welded to a part of the side end edge thereof, and then attached to the bag body so that the closure part is integrated with the frame body to form a self-standing bag having a closure part. Therefore, in the present invention, when making a self-supporting bag, for example, only the bottom side and bottom side edges of the film are heat-welded so that only the bottom film and the side film of the bag body are fixed. Even if it is installed, the above-mentioned frame is attached, and by joining the unwelded parts of the upper and outer edges of the bag body, which are the unbonded edges, a self-supporting bag with a closure is manufactured. Can be sacked. Further, even when the bag is manufactured with a joining strength such that the portion other than the lower side of the side edge is formed into a bag shape, the joining strength can be reinforced by attaching the frame body. Therefore, the edges of the bag body can be joined more easily and reliably. That is, the bag body may be completely bag-formed or may be incomplete if the bottom film is heat-welded, but by using a bag body that is more completely bag-formed, The self-supporting bag has excellent strength, and it is easier to attach the closure and frame.
In addition, it becomes reliable and is suitable as a method for producing the self-standing bag of the present invention.

[0011]

EFFECTS OF THE INVENTION Since the self-standing bag of the present invention is flexible and excellent in self-supporting property, it can function as a packaging bag having self-supporting property at the time of use. Satisfying the requirement, it can be rolled up into a small volume after use and discarded.
It also has excellent attachment strength for the closure part.
It is also possible to reinforce the joint strength. Therefore,
The self-supporting bag of the present invention is easy to use during use and has excellent strength as a packaging bag, and can be easily reduced in volume after use and is suitable for environmental protection. Further, according to the method for manufacturing a self-supporting bag of the present invention, it is possible to easily and reliably manufacture a self-supporting bag having the above-mentioned characteristics and particularly excellent in strength as a packaging bag.

[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 is inflated, which illustrates one configuration example of the self-supporting bag of the present invention. The self-standing bag 1 is provided with a closure part 3 at the upper end of the bag body 2 and has one side edge 2a to the upper edge 2b.
A substantially inverted concave type frame body 4 integrally formed with the closure part 3 is attached to the other end edge 2a so as to sandwich each end edge 2a, 2b, 2a from the outside.

The bag main body 2 is formed by folding the bottom of the film into four folds so that a long film has side films 2c, 2c and a bottom film 2d folded in an inverted V shape at the bottom, which will be described later. As described above, the side edges 2a, 2a of the side films 2c, 2c are joined by heat welding, and a part of the folded portion of the bottom film 2d is heat welded in a substantially semi-arc shape to form a lower substantially semi-arc weld portion. By forming 2e and 2e, the bottom surface 2f is formed. The bag body 2 has bottom strength and self-supporting property reinforced by lower semi-circular arc welded portions 2e and 2e.

As the films (side films 2c, 2c, bottom film 2d) constituting the bag body 2, single-layer or multi-layer films are used. These films may be the same as conventional films, but do not necessarily have heat-welding properties, and when formed into a bag, the film surface on the outer surface side is bonded to the resin to be injected. It is preferable that the property is good. The multilayer film is a coextrusion film,
It is a laminated film or the like, and is a coextrusion type or the like with a gas barrier layer (EVOH, vinylidene chloride, ceramic vapor deposition, etc.) or the like in order to impart a necessary function to a stretched or unstretched polyolefin, nylon, polyester film or resin layer. Laminate type films and the like are preferably used.

The thickness of the film is 20 to 900 μm.
m is applied, and a thick film is suitable from the standpoint of self-supporting property, but a thin film is preferred from the viewpoint of flexibility and lightness, and even if it is a thin film, the self-supporting property can be secured by attaching the frame body 4. From moldability and handleability,
A desirable thickness is 60 to 200 μm. The film is not limited to a synthetic resin film, and 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 purpose of use of the packaging bag. Here, usually, a self-standing bag with a closure part is manufactured by inserting a closure member into the upper end portion of the self-supporting bag by another operation using a hand or an automatic insertion machine, and heat-welding the closure member. In the case of a thick material, it is difficult to surely bond the both ends of the closure member, and the welding operation is often difficult. However, in the present invention, since it is molded so as to be integrated with the frame body 4 as will be described later, there is no such difficulty.

The frame body 4 is integrally molded with the closure portion 3 by injection molding or the like, or the closure portion 3 is formed.
Are molded in advance and integrally molded in a mold. These forming resins are not particularly limited as long as they can be injection-molded and can be bonded to the edge of the bag body 2. But not
Not only general-purpose resins such as polyethylene and polypropylene resins, but also injectable plastics such as nylon,
Blends or copolymer resins of polyester, various engineering resins and elastomers can also be used.

The frame body 4 is formed along one side end edge 2a to the upper end edge 2b to the other side end edge 2a of the bag body 2 made of a resin film which is molded in advance into 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. Frame 4 shown in 1
As described above, even if the length is such that the lower part of the side edge is left, as described above, a part of the folded portion of the film of the bag main body 2 is heat-welded in a substantially semi-arc shape to the lower portion. Since the bottom strength and the self-supporting property are reinforced by the semi-arc-shaped welded parts 2e and 2e and the heat-welding parts at the side edges, the self-supporting property and the strength as a bag, which are the objectives of the present invention, can be obtained.

As described above, the side edges 2a, 2 of the frame 4 are
When the length of the portion corresponding to a is set such that the lower portions of the side edges 2a and 2a remain, the length of the corresponding portion of the frame body 4 is 60 times the total length of the side edges. % Or more, particularly preferably 80% or more. 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 heat-welded so that the side edges 2a, 2a form the bottom surface 2f, the tip of the frame body is provided at least on the upper side of the heat-welded portion. The length should be as wide as possible, and the part below it should remain.

Although the width and thickness of the frame body 4 are not particularly limited, for example, like the frame body 4 shown in FIG. 1, the tip side of the portion corresponding to the side edges 2a, 2a (see the drawing). If the shape is such that the lower side) is tapered, the width is 1 to 20 mm, particularly 5 to 10 m in a portion having a uniform width.
m, and the thickness is 1 to 10 mm, preferably 2 to 5 mm. The frame body 4'shown in FIG.
When the whole is almost uniform as described above, 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 attachment strength to the bag body 2. If the thickness is too thick, the amount of resin used increases, and from the viewpoint of disposability. It is not preferable, and if the width is too wide, it may be difficult to obtain a sufficient inner volume of the self-standing bag.

Next, an example of the construction of the method for producing a self-supporting bag according to the present invention will be described with reference to FIGS. FIG. 2 is a schematic front view of the self-supporting bag before being attached to the frame, which is manufactured by the first step of the manufacturing method, and FIG. 3 is another configuration of the self-supporting bag of the present invention obtained by the second step. It is a schematic front view of an example.

The first step is to use an ordinary self-supporting bag-making machine to form a self-supporting bag having side films 2c, 2c and a bottom film 2d folded in an inverted V shape at the bottom so as to form a bag body. The long film constituting 2 is folded so that the lower side is folded in four, and the lower edge and the one side edge 2
a, the other side edge 2a is joined by heat welding such as heat sealing or ultrasonic sealing, and the portions 2e, 2e of the folded portions of the film are joined by means such as heat welding so as to form a substantially semi-arc shape. By doing so, the side films 2c, 2c and the bottom film 2d are fixed, and the bag body 2 having an open upper end as shown in FIG. 2 is manufactured. In addition,
In this step, a part of the upper edge 2b of the bag body 2 may be heat-welded as long as the attachment property of the closure member is not impaired as described later.

Here, the one side edge 2a and the other side edge 2a are joined to each other as long as the side surface films 2c, 2c and the bottom surface film 2d are fixed and the bottom surface 2f is formed. Although it is possible to heat weld only the lower end side of the other side edge 2a, 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 (bottom film It is preferable to include the base) because the strength of the self-supporting bag of the present invention is excellent. And 2/5 of the total length of the side edge
Between the upper side and the lower end of each side edge 2a, 2a (see FIG.
It is also possible to heat-weld only the inside arrows 2g, 2g). In particular, when the frame body is not attached over the entire length of the both side edges like the self-supporting bag shown in FIG. 1, the portions of the both side edges where the frame body is not attached should be heat welded in advance. Requires. It is desirable that the lower substantially semi-circular arc-shaped welded portions 2e, 2e formed to improve self-sustainability are also heat-welded in advance in consideration of workability.

Further, even when the one side edge 2a and the other side edge 2a are joined over the entire length, the joining strength as in the conventional self-standing bag is not particularly required, and for example, the bag shape is taken for the time being. It may be about. However, even in this case, it may not be possible to secure the adhesive strength of the bottom portion (the root of the bottom film is most stressed in the self-supporting bag) only with the frame body, so at least the portion forming the bottom surface 2f, It is preferable to heat-bond with sufficient bonding strength in advance. Further, when the frame does not extend over the entire length of both side edges as described above, it is preferable that the portions of both side edges where the frame is not attached are heat-welded in advance with sufficient bonding strength.

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 position of the back surface film can be adjusted. It becomes easier, and even if the closure member and the frame can be integrally molded at the correct position, or even if a separately molded closure member is used, it can be integrally molded with the frame at the correct position by a method such as insert molding. be able to.

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 portion 3 is located at a predetermined position of the upper end of the film constituting the bag body 2. At the same time as injection molding at the location, the bag body 2 is made of thermoplastic resin extending from the closure part.
Edge 2b, both side edges 2a, 2a of the film forming the
The frame 4'is injection molded so as to cover the outer surface (back surface) of
The frame body 4'is attached to the upper end edge 2b of the bag body 2 and both end edges 2a, 2a.
The self-standing bag 1'shown in FIG.

The self-standing bag is filled with the contents (not shown) from the closure part to form a self-supporting shape with a wide bottom surface, and the closure part is sealed and then stored and transported. When used, the contents can be discharged from the closure part. The type of content is not particularly limited, and by appropriately selecting the type of film that constitutes the bag body, the material of the closure part, etc., it is possible to support a wide range of content items. It is preferable to have one, for example, a liquid, a viscous substance, a powder, a solid form having a small diameter, or the like can be suitably contained. This self-supporting bag can maintain its self-supporting property until the contents are exhausted, since it can function as ribs at both side edge portions of the frame body, and can be rolled and made smaller at the time of disposal. Therefore, according to the self-supporting bag of the present invention, the bottle,
A flexible container that can replace bottles, cans, etc. and can be fitted with various closures can be obtained.

The present invention is not limited to the above-described structure. For example, the lower substantially semi-arcuate welding portion is not provided, but a simple linear lower end welding portion or the lower substantially semi-arcuate welding portion is provided. In addition to the linear lower end welded portion, a linear welded portion at an angle of 45 ° extending from the base of the bottom film is provided in place of the bottom portion, and the bottom film is different from the side film. Various changes may be made without departing from the scope.

[Brief description of 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 the bag body obtained in the first step for explaining one structural example of the method for producing a self-supporting bag of the present invention.

FIG. 3 is a schematic front view of the self-supporting bag obtained by the second step of the manufacturing method.

[Simple explanation of symbols]

1,1 'freestanding bag 2 bags body 2a side edge 2b Upper edge 2c Side film 2d bottom film 3 Closure part 4,4 'frame

Continued front page    F-term (reference) 3E064 AB25 BA24 BA36 BA54 BB03                       BC08 BC18 EA04 EA12 FA04                       HF03 HG02 HG03 HN65

Claims (4)

[Claims] 1. A self-standing bag having a closure part 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. As described above, 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, and the closure portion is integrated from the upper end edge to both end edges of the bag body. A self-standing bag characterized in that a substantially inverted concave frame body molded into is attached. 2. The self-supporting bag according to claim 1, wherein the frame is attached at a side edge where the heat-welding portion is present, leaving a part or all of the heat-welding portion. 3. The self-supporting bag according to claim 1, wherein the frame body is attached so as to cover the outer surface of each edge of the bag body. 4. The method for producing a self-supporting bag according to claim 1, 2 or 3, wherein the bottom edge of the bag body and at least the bottom film are present so that at least the bottom film and the side film are fixed. A self-supporting bag having a closure part attached to the bag body so that the closure part is integrated with the frame body after heat-sealing and bonding a part of the side edges. Manufacturing method.