WO2004018314A1 - Gusset bag and method of producing the same - Google Patents

Abstract

A gusset bag with side films tucked in the side and an opening formed in the upper edge, wherein the gusset bag at least has a reinforcing resin layer in the side edge.

Description

 Specification

Gazette bag and manufacturing method thereof

Technical field

 The present invention relates to a gusset bag which is flexible, has excellent self-sustainability, and also has excellent attachment strength for a part of a closure, and a method for manufacturing the gusset bag. Background art

 Conventionally, a gusset bag made of a soft packaging material mainly composed of a plastic film has been known as a packaging container (bag) for storing a liquid or the like.

 However, the conventional gusset bag has a problem in that as the content of the filled content decreases, the upper part bends, thereby impairing independence and losing its function as an independent bag. In particular, some gusset bags for liquids have a closure for pouring out the contents, in which case the upper part becomes heavy and lacks independence. Had become. In the conventional gusset bag with a part of the closure, a predetermined part of the periphery is joined by heat welding to create the bag body, and a part of the closure is separately molded to form a bag body. A part of the closure was attached by inserting a part of the closure by hand and thermally welding it 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 mounting strength.

On the other hand, molded containers, of course, have sufficient independence, but they cannot be folded down or made smaller 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-supporting bag until the contents are exhausted, and when discarded, it can be folded down to reduce the capacity, as well as the mounting strength of a part of the closure It is an object of the present invention to provide a gusset bag excellent in the above and a method for producing the same. The present invention provides the following gusset bags and a method for manufacturing the gusset bags to achieve the above object.

 [I] A gusset bag in which a side film is folded into a side portion and an opening is provided in an upper edge portion, wherein the gusset bag has a reinforcing resin layer at least in a side edge portion.

 [I I] The gusset according to [I], wherein the reinforcing resin layer is further provided on an upper edge portion.

[II] The gusset bag according to [II], wherein the gusset bag is joined to the reinforcing resin layer and a part of the closure is provided in the opening.

 [I V] The gusset bag according to [I I I], wherein the reinforcing resin layer and a part of the closure are formed in a body.

 [V] A method for producing a gusset bag in which a side film is folded into a side portion and an opening is provided in an upper edge portion, wherein a resin is provided on the side edge portion of the gusset bag or on the side edge portion and the upper edge portion. For producing a gusset bag in which a reinforcing resin layer is formed by injecting a slab.

 [VI] The method for producing a gusset bag according to [V], wherein the resin is injected to form a closure portion in the opening and to form the reinforcing resin layer integrally therewith.

 That is, in the gusset bag of the present invention, the reinforcing resin layer, in particular, the portion of the reinforcing resin layer at the side edge portion becomes a so-called rib of the bag body, and functions as a bag support, thereby improving the independence of the bag body. Even when a part of closure is provided, sufficient independence can be maintained until the contents are exhausted. When a part of the closure is formed integrally with the resin layer, the attachment strength of the part of the closure is excellent.

 It should be noted that the reinforcing resin layer at the side edge portion exhibits a reinforcing function if formed at at least one side edge portion of the four side edge portions, but preferably at two places, more preferably at two places. It is effective to be formed in all four places. The reinforcing resin layer may be formed at least on a part of the side edge, and may be formed entirely from the upper end to the lower end of the side edge.

And if this reinforcing resin layer is the side part, the ridge part, the inside of the gusset fold part (side It may be provided on either the front side or the back side, but if it is provided only on the front side and Z or the back side, the gusset bag can be easily folded, and the reinforcing resin The formation of the layer is also easy, and it is particularly preferable when the reinforcing resin layer is extended from the side edge that expands when the contents are stored to the upper edge, because the gusset bag is easily opened.

 In addition, the closure portion is used as a spout when the contents of the gusset bag of the present invention are particularly fluid, but a part of the closure is independent of the gusset bag and the attachment of a part of the closure. From the viewpoint of securing strength, it is preferable that the reinforcing layer is formed integrally with the reinforcing layer.

 A part of the closure may be integrally molded at the same time as the molding of the reinforcing resin layer. However, a part molded in advance may be integrated by in-mold molding or the like at the time of molding the reinforcing resin layer. In this case, it is preferable that a part of the closure is joined to the reinforcing resin layer.

 The gusset bag of the present invention is preferably manufactured by forming a bag body according to a conventional method, and then forming a reinforcing resin layer on the upper edge and side edges of the bag body. If the upper edge (side) of the bag body is unjoined when the body is formed, or if the side edges are joined with a joint strength that is such that the bag body is initially in a bag shape, the bag By forming the reinforcing layer so as to cover the upper and lower edges of the main body, the bonding strength can be reinforced, and the side edges of the bag main body can be more reliably bonded. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic perspective view of a gusset bag illustrating one configuration example of the gusset bag of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawing, 1 is provided with a rectangular bottom portion 2, a front portion 3, a back portion 4, and both side films 5 and 6. It is a gusset bag body. The films 5 and 6 on both sides are provided so that they can be folded inward, and the bottom part 2 can be folded toward the back part 4 when the films 5 and 6 are folded inward. May be formed in the form of a square bottom. The upper edge 7 of the bag body 1 is joined and formed in a state in which the upper ends of the front and back portions 3 and 4 are overlapped, and an opening 8 is provided in the center thereof, and the opening 8 is provided. Is fitted with a closure 9.

 Reference numeral 10 denotes a reinforcing resin layer formed only on the front surface 3 and the back surface 4 of the upper portion 7 and each side edge of the bag body 1. In this case, in the illustrated embodiment, the reinforcing resin layer 10 formed on each side edge is formed near the lower end of each side edge. Preferably, the resin layer is formed at least from the upper end portion of each side edge portion to the center portion in the ridge line direction. Of course, the resin layer may be formed over the entire length of each side edge portion.

 In the example shown in the drawing, when forming the reinforcing resin layer 10 in this manner, the closure 9 is integrally joined to the opening 8 by the same resin.

 Here, each film constituting the bag body 1 is formed by a method of bonding the films when manufacturing the gusset bag of the present invention, an adhesive property with the resin layer, and a type of contents to be filled in the gusset bag of the present invention. Is appropriately selected in view of the above. In producing the gusset bag of the present invention, when the films are heat-welded to each other, it is preferable to impart heat-welding properties to the film. Further, it is preferable that the film surface on the side that becomes the outer surface when formed into a bag has good adhesiveness to the resin forming the reinforcing resin layer 10.

The film may be a single layer or a multilayer. Examples of the multilayer film include a co-extruded film and a laminated film. As the constituent material of the single-layer or multi-layer film, for example, stretched or unstretched polyolefin, nylon, polyester film, and as a gas barrier material, EVOH, vinylidene chloride, ceramic vapor deposition and the like are suitably used. The film is not limited to those made of synthetic resin, and may be a single-layer product of paper or metal foil (such as aluminum foil) or a laminate product. Alternatively, a plastic laminated film having a different kind of material such as a multilayer plastic film, a metal deposition layer, a metal foil, and paper is preferable.

 As the thickness of the above film, a thickness of 20 to 900 m is applied, and a thick film is suitable from the standpoint of independence, but a thin film is preferable from the viewpoint of flexibility and lightness, and a thin film is used. Also, by providing the reinforcing resin layer 10, independence can be secured. From the viewpoint of moldability and handleability, a desirable thickness is preferably from 60 to 200 m.

 The shape and size of the closure part 9 are not particularly limited, and may be any shape and size according to the intended use of the packaging bag. Here, the self-standing bag with a part of the closure is usually manufactured by inserting the closure member into the opening 8 of the bag body 1 by hand or by another operation using an automatic insertion machine and heat-sealing the bag. When the thickness of some materials 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 it is possible to join or mold integrally with the reinforcing resin layer 10 so as to be integrated with the reinforcing resin layer 10.

 The material of the closure part 9 is not particularly limited, and is appropriately selected in consideration of the contents to be filled in the gusset bag of the present invention, the bonding property with the reinforcing resin layer 10 or the self-sustainability of the gusset bag. General-purpose resins such as polyethylene and polypropylene, engineering resins such as nylon and polyester, and various elastomers may be used.One of these may be used alone, or two or more may be used in combination in the form of copolymerization or blending. Is also good. The material of the reinforcing resin layer 10 may be the same as or different from the material of the closure part 9, but a material that can be injection-molded and can be joined to the edge of the bag body 1 is preferably used. For example, general-purpose resins such as polyethylene and polypropylene, engineering resins such as nylon and polyester, and blended resins or copolymerized resins thereof with an elastomer or the like can be mentioned.

The width and thickness of the reinforcing resin layer 10 are not particularly limited. For example, if the tip side (bottom side) of the portion corresponding to the side edge is tapered, It is preferable that the portion having a uniform width is formed to have a width of l to 20 mm, particularly 5 to 10 mm, and a thickness of 1 to 10 mm, particularly 2 to 5 mm. The whole is almost In the case of having a uniform shape, it is preferable that the average width and the average thickness are within the above ranges. If the width is too narrow or too thin, it may be difficult to obtain sufficient attachment strength to the bag body 1.If the width is too wide or too thick, the amount of resin used will increase However, it is not preferable from the viewpoint of disposability, and the openability of the gusset bag is reduced, and it may be difficult to obtain a sufficient internal volume.

 When the length of the portion corresponding to the reinforcing resin layer 10 formed on the side edge is made such that the lower portion of the side edge remains as an uncovered portion, the reinforcing resin layer 1 The length of 0 is preferably at least 60%, more preferably at least 80% of the total length of the side edge. In this case, assuming that the uncovered portion has a length equal to the folded diameter of the side film in the lower seal portion and the width of the lower seal, the reinforcing resin layer 10 reaches the mounting surface when it becomes independent, and the bottom of the lower seal portion Since the reinforcing resin layer 10 does not exist in the part 2, the self-sustainability is excellent.

 The gusset bag body 1 can be manufactured by a known method. The reinforcing resin layer 10 formed on the upper edge portion 7 and each side edge portion may be formed by pasting a resin layer molded in a belt shape in advance with an adhesive or a heat seal. It can be formed by injecting a resin into each side edge. In this case, the opening

When the closure part 9 is provided in 8, it is preferable to mold the closure part 9 into the opening 8 by simultaneously injecting the same resin during this injection molding. In addition, a part of the closure 9 is previously molded, and when the reinforcing resin layer 10 is formed by injecting a molten resin into the bag body 1 in a mold, the closure part 9 is integrally joined. You can also.

Since the gusset bag of the present invention is flexible and has excellent self-sustainability, it functions as a self-supporting packaging bag when used, and satisfies self-sustainability even if it has a closure portion until 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 gusset bag of the present invention is easy to use when used, and has excellent strength as a packaging bag, and can be easily reduced in volume and weight when disposed after use, and is suitable for environmental protection. . Further, according to the method for manufacturing a gusset bag of the present invention, it is possible to easily and reliably manufacture a gusset bag having the above-described characteristics and having particularly excellent strength as a packaging bag. In addition, by selecting the material of the bag body, the type of molded closure, and the type of resin, a self-supporting gusset bag capable of handling a wide range of contents can be manufactured. The gusset bag of the present invention can be used as an alternative container for bottles, bottles, and cans.

Claims

The scope of the claims  1. A gusset bag in which a side film is folded into a side portion and an opening is provided in an upper edge portion, wherein the gusset bag has at least a reinforcing resin layer in a side edge portion. 2. The gusset bag according to claim 1, wherein the reinforcing resin layer is further provided on an upper edge portion. 3. The gusset bag according to claim 2, wherein a closure portion is provided at the opening portion by being joined to the reinforcing resin layer.  4. The gusset bag according to claim 3, wherein the reinforcing resin layer and a part of the closure are formed in a body.  5. A method for manufacturing a gusset bag in which a side film is folded into a side portion and an opening is provided in an upper edge portion, wherein a resin is applied to the side edge portion of the gusset bag or the side edge portion and the upper edge portion. A method for producing a gusset bag that is injected to form a reinforcing resin layer.  6. The method for manufacturing a gusset bag according to claim 5, wherein a part of the closure is molded in the opening by injecting a resin, and the reinforcing resin layer is formed integrally therewith.