JPS61261031A - Manufacture of square bottom of plastic film bag - Google Patents

Abstract

PURPOSE:To enable to manufacture a bag convenient for use through a simple process, by a method wherein a gusset is provided on a part corresponding to the bottom of the bag, a plate is inserted between folds, and fused. CONSTITUTION:Gussets 5, 6 are provided on parts corresponding to the bottom of a bag made of film raw fabrics, a plate 8 is inserted between folds, against which a wedgy hot blade is pushed at every width of a baggy material from the outside and inside, fused square bottom 10 is formed by fusing respective two sheets of films 1, 2 on the outside and inside of the plate 8 and an unnecessary film 12 is cut off. A linear hot blade is pushed against the film raw fabrics at every width of the baggy material, which is fused and the side fringe part 11 of the baggy material is formed. At the time of cutting-off of the unnecessary film, it is desirable to either scratch off the same mechanically or add a process blowing off the same by compressed air. With this construction, a matter that a hand bag having identical strength and convenient for use can be manufactured through a simple process is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for manufacturing a square bottom of a plastic film bag.

Currently, bags of plastic film bags are used in very large quantities for packaging and transporting goods.

We also have bags such as plastic film bags,
Bags with a so-called square bottom structure having a rectangular bottom are convenient for storing items, and are therefore preferred.

The present invention relates to a novel method for manufacturing a square bottom structure of a plastic film bag.

BACKGROUND OF THE INVENTION Various methods of manufacturing the square bottom structure of plastic film bags, which are the subject of the present invention, have been proposed.

As a known technique closest to the present invention, a manufacturing method is known in which a gusseted fold is provided at the bottom of a plastic film bag, and the film is fused to the left and right corners of this portion at an angle of 45 degrees to form a square bottom.

C1 Problems to be Solved by the Invention In the square base manufactured by the above-mentioned known technique, a double-structure right isosceles triangular film is attached to the lower part of the outside of the left and right sides of the square base with the right angle point facing upward. ing. The outer film of this double structure not only does not contribute anything to the strength of the square bottom, but also has a bad appearance and is difficult to handle when used in a bag with a wide square bottom. It is.

Further, when manufacturing a square bottom by the conventional method, the angle of the fused portions at the left and right corners is limited to 45 degrees.

In other words, if this angle is smaller than 45 degrees with respect to the bottom side of the bag, the base of the right-angled isosceles triangle of the extra double-layered film will be longer than the width of the square base, and when the base is made square, the corresponding The adhesive film is loose and the appearance is poor. On the other hand, if this angle is made larger than 45 degrees, the length of the bottom of the adhesive film will be shorter than the width of the square bottom of the bag, and the width of the square bottom will be limited by the adhesive film, causing slack at the bottom of the bag. arise.

The present invention provides a method for manufacturing a square bottom that does not have these drawbacks.

20 Means for Solving the Problems The present invention is designed to continuously unwind a long tube-like film or a half-folded strip-like film, which is the raw material for the bag body, and to In the production and rental process of fusing and cutting the film, a gusset fold is provided in the part corresponding to the bottom of the bag of the original film, a plate is inserted between the folds of the gusset fold, and the front and back sides are cut against the plate. Then, apply a wedge-shaped thermal force to each width of the bag,
The two films on the front and back sides of the plate are fused together, the wedge-shaped portion of the film is cut off, and a linear thermal force is applied to the original film for each width of the bag. The square bottom of the plastic film bag is manufactured by fusing and cutting the plastic film bag to form the side edges of the bag body.

The tubular film material used in the present invention can be used as it is produced by In7 Laser processing.

In the process of fusing the gusset folded portions in the present invention, a metal plate or the like is inserted between the two sets of gusset folded films in order to prevent the two sets of gusset films from being fused together.

A wedge-shaped thermal force is then pressed against a metal plate or the like from the upper and lower backs and fronts to form a fused portion, and the wedge-shaped unnecessary film B is cut off by the thermal force.

At this time, either mechanically scrape off the separated film or
It is desirable to add a step of blowing off the film with compressed air. If this is not done, the cut off unnecessary film will cause problems in the subsequent process of fusing and cutting the side edges of the bag.

In this way, the present invention separates and removes unnecessary film portions by a fusing process (this is different from the conventional manufacturing method for square bottoms. Conventionally, the process was simply fused using a hot iron).

In the wedge-shaped thermal force fusing process, it is desirable that the apex of the wedge-shaped thermal force correspond as closely as possible to the inner fold line of the gusset fold.

After or simultaneously with the step of fusing and cutting the corner bottom portion, a portion corresponding to the side edge of the bag body portion is fusing and cutting to fuse and cut the side edge of the bag body. At this time, it is necessary to cut the material so that it coincides with the apex of the wedge shape.

To, Example 1 of the present invention! ! The method will be explained in more detail using examples.

A long strip-shaped film is folded in half along its longitudinal direction, and the fold is reversely folded inward to create a gusset-fold, thereby producing a strip-shaped film having gusset folds 5 and 6 as shown in the cross-sectional structure of FIG. Make it.

These Z-folds are performed to form the bottom of the carrier bag into a square bottom structure.

Next, while feeding the gusset-folded strip film onto a workbench, a front tape film 3 and a group tape film 4 are placed on the upper surface of the front film 1 and the lower surface of the back film 2, respectively, along their respective upper edges. Supply along. The cross-sectional structure of the strip-shaped film assembled in this way when viewed from the side is as shown in FIG.

Next, in a conventional manner, the feeding method of the film strip is switched to intermittent feeding in which the film strip is temporarily stopped, and the film strip is fed onto the fusing workbench. On the fusing workbench, at the upper edge of the film strip, front film 1 and back film 2 are
A metal plate 7 is installed between them. This metal plate 7 is inserted from above the strip-shaped film.

On the other hand, a metal plate 8 is also installed between the folded parts of the gusset fold 5 and the gusset fold 6.

A gap is provided in the welding table where the metal plate is installed, through which a hot trowel or heat force can be applied to the metal plate from below the rigging.

A hot iron is applied to the metal plate 7 on the fusion workbench from above and below. An inverted-shaped hot iron as shown in FIG. 2 is pressed against the metal plate 7 inside the upper edge of the film strip from above and below at the same time. At this time, the front film 1 and the front tape film 3
As shown in the diagram between
is formed, and a backing film 2 and a backing tape film 4 are formed.
Similarly, handheld fusion is formed between the two, but the attenuating film 1 and the back film 2 are not fused because they are blocked by the metal plate.

At the same time as this fusion process, the gusset fold 5 and the gusset fold 6 are
A wedge-shaped thermal force, as shown in the figure, is applied to the metal plate 8 located in the folded part between the two from above and below. At this time too,
The upper and lower two-sheet sets of Z-folded films are each fused in a wedge shape by thermal force to form a square bottom fusion bond 9, and the unnecessary film 12 is cut off. The cut off unnecessary film 12 is removed by mechanically scraping it off or by blowing it away with compressed air.

After the fusing step, the film strip is fed to the workbench for the final fusing step. Here, the strip-shaped film is fused in the transverse direction in accordance with the position of the apex of the fused wedge provided in the gusset folded portion, which is the width of the bag body. By this fusing and cutting step, it is possible to simultaneously cut the bag body into widths and fuse the side edges of the bag body 11.

A carrying bag as shown in FIG. 3 can be manufactured by a process with more than zero effect. When the bag is expanded according to the square bottom structure, it becomes a square structure as shown in Figure 4. Of course, FIG. 4 is shown as an explanatory drawing, and since the film is flexible at the upper edge of the bag, it does not have a square shape as shown in the figure. In this way, the bag can be hung by unfolding the bag, placing an item inside, and grasping the tape-like film of the carrying portion from the outside.

In the manufacturing method of the present invention, if the bottom melting step is carried out at an angle of 45 degrees to the lower side of the bag, the bottom of the bag will accurately form a rectangular parallelepiped when the bag is unfolded. However, this angle is 4
If the angle is smaller than 5 degrees, the bottom of the bag will be shaped like a boat's bottom with slanted corners as shown in Figure 6. On the other hand, if the angle is made larger than 45 degrees, a bag can be manufactured in which the bottom is wider than the opening of the bag, as shown in Figure tJtI7. In this way, by gradually changing the inclination angle of the wedge-shaped thermal force, and by combining this with changing the width of the folds of the gusset fold 5, it is possible to obtain bag bodies with a wide variety of shapes. You can make bags as you wish.

G. Effects The present invention has made it possible to efficiently manufacture a carrier bag that has the same strength, good appearance, and is convenient to use through a simple process.

Furthermore, the manufacturing method of the present invention makes it possible to manufacture square bottoms with various structures as desired depending on the purpose by changing the inclination angle of the thermal power used in the bottom melting process.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams for explaining one aspect of an embodiment of the manufacturing process of the present invention, and FIGS. 3 and 4 are diagrams for explaining the structure of a carrier bag with a square bottom structure manufactured by this embodiment. FIG. 3 is a plan view of the bag when it is folded, FIG. 4 is a perspective view of the bag when the corner bottom is unfolded, and FIG.
FIG. 6 and FIG. 6 are respectively perspective views of another embodiment of a carrier bag having a square bottom structure according to the present invention in a used state. The symbols in the figure are 1: Front film, 2: Back film, 3: Front tape film, 4: Back tape film, 5, 6: Y-Z fold, 7: Metal plate for fusing the handbag, 8: Metal for bottom fusing. Plate, 9; Handbag fusion part, 10; Square bottom fusion part, 11;
Side edge fused portion, 12; unnecessary film. Figure 1 Figure 2? Figure 3 Figure 5 Figure 4 Figure 6

Claims (1)

[Claims] In the bag-making process, the raw material for the bag body, which is a long tube-shaped film or a half-folded strip-like raw material, is continuously fed out and cut into pieces for each width of the bag. A gusset fold is provided in the part corresponding to the bottom of the cloth bag, a plate is inserted between the folds of the gusset fold, and the plate is inserted from the front and back sides,
A wedge-shaped hot blade is pressed against each width of the bag to fuse the two films on the front and back sides of the plate, and cut off the part of the film surrounded by the wedge shape. A method for manufacturing a square bottom of a plastic film bag, characterized in that a linear hot blade is pressed against the original film at each width, and the blade is fused to form the side edges of the bag body.