JP5261899B2 - Self-supporting bag - Google Patents

Description

  The present invention relates to a self-supporting bag having a two-piece structure in consideration of environmental problems including a side sheet and a bottom sheet.

  Conventionally, refill contents such as liquid detergent, kitchen detergent and softener, liquid contents such as sauce, soy sauce, dressing and juice, solid contents such as confectionery, powder contents such as wheat flour and tempura powder As packaging bags for storing goods, self-supporting bags having a display effect at stores are widely used.

  In such a self-supporting bag, the two bottom sheets facing each other (front wall, rear wall) and two outer folding lines centered on the inner folding line connected to the side sheets are folded into a substantially W-shaped cross section. A one-piece self-supporting bag consisting of a sheet (bottom wall) and a side sheet (trunk wall sheet) are placed facing each other, and a bottom sheet (bottom wall sheet) is formed at the lower end of the side sheet. A two-piece self-supporting bag is known (see, for example, Patent Documents 1 and 2).

  On the other hand, in recent years, with increasing consumer environmental awareness, packaging bags that take environmental issues into consideration have been demanded by consumers. Along with such changes in consumption behavior, materials that effectively use biomass as an environmentally friendly material not only reduce dependence on fossil resources such as oil, but also improve environmental problems faced by modern society and recycle It is attracting attention because it can contribute to the formation of society. One example is polylactic acid, and polylactic acid-based resins are biodegradable, so that they naturally hydrolyze in soil and water, and become harmless degradation products by microorganisms. Even if incinerated, the incinerator will not be damaged because the amount of combustion heat is small. In addition, since the starting material is derived from plants, it has features such as being able to escape from depleted fossil resources such as petroleum, and plastic molded products using polylactic acid, such as films, sheets, packaging bags and bottles, etc. Research has been conducted on the production of such containers and the like, and a fusing seal bag that has already been made with a fusing seal using a polylactic acid resin film has been disclosed (for example, see Patent Document 3).

However, polylactic acid-based resin films are inferior in flexibility, toughness, and heat resistance, and are difficult to use as a packaging material for packaging bags. Although there is no practical problem with light packaging bags such as individual packages of snacks, it is particularly difficult to use heavy packaging bags that are filled with liquid or powder contents, such as powder detergent, as a laminate for self-supporting bags. It was. When a self-supporting bag is made of, for example, a laminate of outer layer / base material / thermoadhesive resin layer using a polylactic acid resin film as the base material of the self-supporting bag, the base polylactic acid resin film is inferior in flexibility and toughness. For this reason, a preferred strength cannot be obtained for the heavy packaging bag. In addition, when a laminate of base material / intermediate layer / thermoadhesive resin layer is used, strength as a heavy packaging bag can be obtained, but the heat resistance of the polylactic acid resin film as the base material is inferior, so two side faces When the bottom part of the self-supporting bag is formed by heat-sealing the peripheral part of the bottom sheet that is inserted by folding in the center with the heat-adhesive resin layer faced to the outer surface at the lower end and facing the heat-adhesive resin layer of the sheet The base material surfaces which the bottom sheet | seat folded in the mountain | hole is opposed closely contact | abuts, and the problem that it cannot fill with the content arises because the bottom part of a self-supporting bag becomes difficult to open.
Japanese Utility Model Publication No. 53-9535 Japanese Utility Model Publication No. 58-22922 JP 2003-291984 A

  Accordingly, the present invention has been made to solve the above-described problems, and is to provide a self-supporting bag having sufficient strength as a packaging bag in consideration of environmental problems.

In order to achieve the above object, the present invention according to claim 1 includes two side sheets made of a laminate having an inner layer, a middle layer, and an outer layer as a thermoadhesive resin layer, A bottom sheet made of a laminate having an inner layer as a heat-adhesive resin layer and an outer layer is disposed so that the surfaces of the inner layers of the two side sheets face each other, and the lower ends of the two side sheets The bottom sheet is inserted in a mountain-folded manner in the middle so that the inner layer surface forms the outer surface, and the inner layer of the bottom sheet folded in a mountain-like manner facing the side edge of the side sheet and the inner layer surface of the side sheet. In the self-supporting bag in which the peripheral portion with the surface is heat-sealed, only the outer layer is composed of a biaxially stretched polylactic acid resin film among the layers of the laminated material forming the side sheet, and forms the bottom sheet the outer layer of the laminate is the biaxially oriented Is constituted by a different type of film and the polylactic acid-based resin film, a self-standing bag, which is a further said higher melting point than the biaxially stretched polylactic acid resin film film.

  The self-supporting bag of the present invention can be a self-supporting bag in consideration of environmental problems by laminating a biaxially stretched polylactic acid resin film on the outer layer of the laminated material forming the side sheet, and by laminating the intermediate layer The effect is that a strong self-supporting bag can be provided. In addition, by using a laminated material provided with a film having a higher melting point than the biaxially stretched polylactic acid resin film on the outer layer of the bottom sheet, the side sheet and the bottom sheet have a two-piece structure using laminated materials having different configurations. In addition, even when the bottom portion of the bottom sheet inserted by folding the side sheet with the mountain is heat-sealed to form the bottom of the self-supporting bag, it is possible to prevent the base material surfaces facing each other of the mountain-folded bottom sheet from sticking to each other .

The above-described present invention will be described in detail below with reference to the drawings.
1 is a front view showing an embodiment of a self-supporting bag according to the present invention, FIG. 2 is a cross-sectional view taken along line XX of FIG. 1, and FIG. 3 is a laminate forming a side sheet and a bottom sheet of the self-supporting bag according to the present invention. 2 is a cross-sectional view taken along line YY in FIG. 2, in which 1 is a self-supporting bag, 2 is a side sheet, 3 is a bottom sheet, 4 is a gusset part, 5 is a notch part, and 6 is a bottom part. Seal part, 7 side seal part, 8 upper seal part, 9 easy opening means, 10 notch, 11 bite, 21, 31 outer layer, 22, 32 intermediate layer, 23, 33 thermal bonding The conductive resin layer is shown.

  An embodiment of a self-supporting bag according to the present invention will be described with reference to FIGS. 1 and 2. The self-supporting bag 1 is arranged by facing the inner layer surfaces of two side sheets 2 (only one side sheet is shown in FIG. 1) made of a laminated material having a thermal adhesive resin layer as an inner layer. A bottom sheet 3 made of a laminated material having a heat-adhesive resin layer as an inner layer at the lower end is inserted into the center with the inner surface facing the outer surface, and is formed into a form having a gusset portion 4 and is folded In the vicinity of the lower ends of both sides of the bottom sheet 3, cutout portions 5, 5 of a substantially semicircular bottom sheet are provided, and the gusset portion 4 is heat-sealed by a bottom-shaped bottom seal portion 6 including a peripheral portion, and the bottom portion is It is formed. Further, both side end portions of the two side sheets 2 on the front and back sides are heat-sealed by side seal portions 7 and 7 to form a body portion, and the bag is formed in a two-piece bag shape having an upper end portion opened. The upper seal portion 8 is an unsealed opening before filling the contents. After the contents are filled from this portion, the upper seal portion 8 is heat-sealed by a deaeration seal or the like and sealed. Further, easy-opening means 9 (described later) is applied in parallel to the upper part of the self-standing bag 1 along the upper edge of the self-standing bag 1, and the edge portions of the side seal portions 7, 7 serving as the opening of the easy-opening means 9. Is provided with a notch 10. Further, on the lower side in the vicinity of the easy-opening means 9, a band-shaped occlusal tool 11 made of polyolefin and made of a male member and a female member that are engaged with each other is parallel to the easy-opening means 9 on the surface of the thermal adhesive resin layer of the side sheet 2. Is provided. In addition, the notch 10 can use the V notch, U notch, I notch, UV notch, the scar group which penetrates the side seal part 7 which consists of a piercing hole in an edge part area | region, etc.

  Next, the laminated material which forms the side sheet 2 and the bottom sheet 3 of the self-supporting bag 1 according to the present invention will be described with reference to FIG. 3 is a cross-sectional view taken along line YY of FIG. 2 showing the bottom seal portion where the side sheet 2 and the bottom sheet 3 of the self-supporting bag 1 according to the present invention are heat-sealed, and the side sheet 2 and the bottom sheet 3 are formed. The layer structure of the laminated material is shown. The side sheet 2 is formed of a laminated material in which an outer layer 21, an intermediate layer 22, and a thermal adhesive resin layer 23 are sequentially laminated. For the outer layer 21, a biaxially stretched polylactic acid resin film is used. The polylactic acid resin used for the biaxially stretched polylactic acid resin film is polylactic acid, a copolymer of lactic acid and other hydroxycarboxylic acid, or a mixture thereof, and does not inhibit the biodegradable effect. Other polymeric materials may be blended in the range. In addition, for the purpose of adjusting molding processability and film physical properties, it is possible to add additives such as plasticizers, lubricants, silica, stable inorganic fillers, ultraviolet absorbers, and modifiers. In addition, the polylactic acid resin film can be used as an unstretched film, but a biaxially stretched film that improves the transparency, gloss, and suitability for lamination and reduces the brittleness of the polylactic acid resin film is preferable. The thickness of the biaxially stretched polylactic acid resin film that can be used is 15 to 50 μm. Examples of lactic acid used include L-lactic acid and D-lactic acid. Examples of other hydroxycarboxylic acids include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, and 6-hydroxycaproic acid.

  For the intermediate layer 22, a film having mechanical and physical strength can be used. For example, a film made of polyester, polypropylene, polyamide, or the like can be used. Although a film is not limited to extending | stretching and unstretched, a stretched film is preferable from surfaces, such as lamination suitability. Also, due to the required functions such as oxygen permeability, water vapor permeability and other gas barrier properties, light shielding properties, etc. on the laminate, metal films such as aluminum, metal oxides such as aluminum oxide, and inorganic substances such as silicon oxide are applied to the film. Vapor deposition may be performed. Furthermore, a film having a barrier property such as an aluminum foil, a plastic film coated with a gas barrier composition such as polyvinyl alcohol, and an ethylene vinyl alcohol copolymer film can be used.

  For the heat-adhesive resin layer 23, a heat-adhesive resin that is welded by heat sealing can be used. For example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear (linear) low-density polyethylene, polypropylene , Ethylene-α-olefin copolymer, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, acid copolymer of ethylene and acrylic acid, ester copolymer of ethylene and acrylic acid ester, etc. Can do.

  The bottom sheet 3 is formed of a laminated material in which an outer layer 31, an intermediate layer 32, and a thermal adhesive resin layer 33 are sequentially laminated. For the outer layer 31, a film having a melting point higher than that of the biaxially stretched polylactic acid resin film is used. For example, a stretched film such as polyester, polypropylene, or polyamide can be used. As the intermediate layer 32 and the thermal adhesive resin layer 33, the same film as the intermediate layer 22 and the thermal adhesive resin layer 23 used for the side sheet 2 can be used.

  Next, the easy opening means 9 will be described. A straight opening cut (not shown) is formed in the intermediate layer 22 in the direction orthogonal to the side seal portions 7 and 7 along the planned opening line parallel to the upper edge at the upper portion of the self-supporting bag 1. The side seal portions 7 and 7 at both ends of the opening cut are provided with notches 10 at positions over the opening cut. With the easy-opening means 9 having such a configuration, when the self-standing bag 1 is torn from the notch 10, the packaging bag can be easily torn by being guided by the straight opening break formed in the intermediate layer 22. Can be opened. Further, the easy-opening means 9 is not limited to this, and it may be easily opened by laminating a film with a laser or a physical scar so as to give an openability, or an easily tearable film. The easy-opening means 9 and the bite 11 are not necessarily required, and may be designed according to the customer's request.

  Next, the present invention will be described in more detail with reference to the following examples.

The outer layer 21 is gravure-printed using urethane-based ink on the corona discharge-treated surface of a 15 μm-thick biaxially stretched polylactic acid film (product name: Terramac TF), and then urethane-based on the printed surface. Immediately before applying the adhesive and heating and pressurizing at the bonding part in the step of laminating the intermediate layer 22 on the adhesive application surface by a dry lamination method using a biaxially stretched nylon film having a thickness of 15 μm for the intermediate layer 22 In the biaxially stretched nylon film, a cutting edge made of a carbide blade having a thickness of 0.2 mm is applied to a predetermined portion of the biaxially stretched nylon film to provide a continuous opening in the web flow direction, and the biaxially stretched nylon film is further laminated. A side sheet of the self-supporting bag of the present invention is formed by laminating a corona discharge treatment of an unstretched low-density polyethylene film having a thickness of 100 μm on the film surface via a urethane-based adhesive. To prepare a layer body.

  Next, a 12 μm thick biaxially stretched polyethylene terephthalate film is laminated with a 15 μm thick biaxially stretched nylon film via a urethane adhesive on the corona discharge treated surface, and the biaxially stretched nylon film surface is further urethane-based. The laminated body which forms the bottom sheet | seat of the self-supporting bag of this invention by laminating | stacking the corona discharge process of a 100 micrometer-thick unstretched low-density polyethylene film through an adhesive agent was produced.

  Using the above laminate, self-supporting bag making machine so that the opening cuts provided in the laminate that forms two side sheets overlap, and the laminate that forms the bottom sheet is further folded in a mountain Inserted into the lower end of the bag, and a polyethylene chuck (occlusion tool) is thermally bonded to the side sheet near the lower side of the opening cut at the top of the self-supporting bag. The dimensions are 22 cm in length, 22 cm in width, and 6 cm in width at the bottom. A self-supporting bag 1 was prepared.

  The self-supporting bag 1 was filled and packaged with 1 kg of powder detergent using a bag-feeding automatic packaging machine (manufactured by General Packer Co., Ltd.) to produce a self-supporting bag sealed with the detergent. So we could fill and wrap without any problems.

It is a front view which shows one Embodiment of the self-supporting bag concerning this invention. It is the XX sectional view taken on the line of FIG. It is the YY sectional view taken on the line of FIG. 2 which shows the layer structure of the laminated material which forms the side sheet and bottom sheet of the self-supporting bag concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Self-supporting bag 2 Side sheet 3 Bottom sheet 4 Gusset part 5 Notch part 6 Bottom part seal part 7 Side part seal part 8 Top seal part 9 Easy opening means 10 Notch 11 Occlusion tool 21, 31 Outer layers 22, 32 Intermediate layers 23, 33 Thermal adhesive resin layer

Claims (1)

Two side sheets made of a laminated material having an inner layer as a heat-adhesive resin layer, an intermediate layer, and an outer layer, a bottom sheet made of a laminated material having an inner layer as a heat-adhesive resin layer, and an outer layer The inner side surfaces of the two side sheets are arranged to face each other, and the bottom sheet is folded in the center at the lower end of the two side sheets so that the inner layer surface forms the outer surface. Insert,
In the self-supporting bag in which the peripheral edge portion between the side end portion of the side sheet and the inner layer surface of the bottom sheet facing the inner layer surface of the side sheet is heat-sealed,
Of the layers of the laminated material forming the side sheet, only the outer layer is composed of a biaxially stretched polylactic acid resin film, and the outer layer of the laminate material forming the bottom sheet is the biaxially stretched polylactic acid resin film. different type of film is constituted by a self-standing bag, which is a further said higher melting point than the biaxially stretched polylactic acid resin film film and.

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