JP2002036394A - Method for manufacturing square bottom bag made of synthetic resin and square bottom bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a square bottom bag made of a synthetic resin making bag making work of the square bottom bag made of the synthetic resin, in particular, work for forming a square bottom part efficient to the utmost, achieving the accurate and simple molding of the bottom shape, extremely contributing to the economical efficiency of a material and having excellent appearance. SOLUTION: In the method for manufacturing the square bottom bag made of the synthetic resin, gusset folds are provided to the left and right edges of a tubular synthetic resin film to fold the film and the folded film is fused to be cut into an arbitrary dimension corresponding to the kind of a bag and one end to be formed into a square bottom of the cut film is linearly fused. Next, the cut film is inserted in a corresponding mold in order to form the arbitrary bottom shape corresponding to the kind of the bag to demarcate the fold of the square bottom part and, thereafter, the linearly fused part is again fused in a strip-like shape from above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a rectangular bottom bag which is formed into a rectangular parallelepiped shape when a product is packed in a synthetic resin bag, and to a square bottom bag.

[0002]

2. Description of the Related Art Conventionally provided synthetic resin square bottom bags have a fusion portion on the bottom surface at each of the triangular sides formed at the left and right outer edges, at the left and right edges, and at the center. Things are widely known.

That is, a tubular synthetic resin film is gusset-folded and folded, and the left and right edges formed on the left and right outer edges are fused to fix a fold defining a bottom shape, and inserted into a mold. It is known to form a bottom surface according to the bag by a method such as that described above, and to perform bottom fusion below the fusion portion.

[0004]

However, in such a conventional method for manufacturing a square bottom bag, the fused portion at the bottom extends over each side as described above. This requires a fused portion in a shape, and the bag-making efficiency of the square-bottom bag is inferior.

[0005] In addition, in the work of fusing the bottom portion, it is necessary to insert a plate or the like between the folds and then perform fusing in order to prevent the films from being bonded to each other. The efficiency of bag making operation is inferior.

Further, depending on the conventional manufacturing method, the band-shaped piece protrudes from the bottom at the fusion site at the center of the bottom, which is not only unfavorable in appearance as a bag, but also hinders standing of the bag. This also poses a problem in the fundamental function of the square bottom bag.

[0007] In the case of a square bottom bag made of paper, which is a widely known manufacturing method in which two trapezoidal folding flaps are overlapped on the bottom surface, the dough used is approximately 2 times smaller than the final bottom area. It is twice as large, and becomes economically inferior.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to improve the efficiency of bag making operation of a synthetic resin square bottom bag, particularly, the operation of forming a square bottom portion to the utmost. , Accurate and simple molding of the bottom shape,
An object of the present invention is to provide a synthetic resin square bottom bag excellent in appearance, which contributes significantly to material economy.

[0009]

In order to achieve the above object, the present invention provides a method of manufacturing a synthetic resin square bottom bag, wherein a gusset fold is provided on the left and right edges of a tube-shaped synthetic resin film and folded. At the same time as fusing to an arbitrary size according to the type of bag, one side forming a square bottom is fused linearly, and then the blown film is formed into an arbitrary bottom shape according to the type of bag. After forming a fold at the bottom of the square, the linearly fused portion is again fused in a band shape from the upper portion.

Further, in a synthetic resin bag, gusset folds are provided on the left and right edges of the tubular synthetic resin film to be folded and melted to an arbitrary size according to the type of the bag, and at the same time one side forming the square bottom is formed. Fused in a line, then, the fused film is inserted into a corresponding mold to form an arbitrary bottom shape according to the type of bag, and after forming a fold at the corner bottom, It is characterized in that it is manufactured by re-fusing the linear fused portion from above into a strip.

The synthetic resin square bottom bag is characterized in that it has only a band-shaped fusion line at the center of the bottom surface.

[0012]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a view showing a bottom portion of an embodiment of a synthetic resin square bottom bag according to the present invention. That is, in the present invention, a linear band-shaped fusion line at the center of the bottom portion (1)
Only the square bottom (X) is formed.

Therefore, in the conventional square bottom bag, the fusion parts (Y) are provided on each side of the right and left triangular folds and on both the left and right edges and the center as shown in FIG. Compared with the invention, the work steps are diversified, and there are cases where it is necessary to insert a plate or the like so that the front and back films are not bonded to each other, which complicates the work.

The present invention solves the above-mentioned problems. Hereinafter, a process for producing a synthetic resin square bottom bag will be described in detail.

First, as shown in FIG. 3, a tube-shaped synthetic resin film is provided with gusset folds on the left and right sides and folded.

Next, according to the type of various bags to be provided, the bag is melted at an appropriate size, and at the same time, one of the corners forming the square base is fused in a linear manner. As a result, in the present invention, the overlap of the front and back films can be reduced to about several millimeters, and the cloth to be used can be used very effectively.

Next, as shown in FIG. 4, a film which has been blown to an arbitrary size is formed through one opening through a mold corresponding to an appropriate bottom shape and bottom area according to the type of various bags to be provided. K) to fix the fold at the bottom of the corner, and again in the above-mentioned pre-fused linear fused portion, fusion is performed again from above using a hot plate (N) or the like.

By the above manufacturing steps, it is possible to complete the square bottom shape as shown in FIG. 1 and the like by an extremely simple method.

Further, by inserting a mold having the same shape as the bottom area, a triangular folded portion on the bottom surface is formed, so that the bottom surface and the triangular folded portion are integrated, a strong square bottom portion is formed, and the mold is formed. When the bag is extracted, the bag is folded in advance, so that the bag can be folded very easily.

[0021]

Since the present invention is configured as described above, the following effects can be obtained.

According to the present invention, by making the fused portion on the bottom surface one place, it is possible to maximize the efficiency of the bag making operation of the synthetic resin square bottom bag, especially the operation of forming the square bottom portion.

According to the present invention, since the molding and the bonding are performed at the same time with substantially the same shape as the bottom area at the time of manufacturing, the accuracy of the bottom shape can be expected, and the folding after the molding can be easily performed.

According to the present invention, since the front and back sides of the tubular synthetic resin film are overlapped by several millimeters, it is possible to greatly contribute to material economy.

According to the present invention, since a smooth bottom surface can be formed without projecting a strip on the bottom portion, it is possible to provide a synthetic resin square bottom bag excellent in appearance.

[Brief description of the drawings]

FIG. 1 is a plan view showing a bottom portion of an embodiment of a synthetic resin square bottom bag according to the present invention.

FIG. 2 is a perspective view showing one embodiment of a synthetic resin square bottom bag of the present invention.

FIG. 3 is a perspective view showing a manufacturing process of the synthetic resin square bottom bag of the present invention.

FIG. 4 is a perspective view showing a manufacturing process of the synthetic resin square bottom bag of the present invention.

FIG. 5 is a plan view showing a bottom surface portion of a conventional synthetic resin square bottom bag.

FIG. 6 is a side view showing a bottom surface portion of a conventional synthetic resin square bottom bag.

FIG. 7 is a plan view showing a bottom surface portion of a conventional synthetic resin square bottom bag.

[Explanation of symbols]

 1 band-shaped fusion line X square bottom Y fusion part K type N hot plate

Claims (3)

[Claims] 1. A tubular synthetic resin film is provided with gusset folds at the left and right edges and folded to fuse to an arbitrary size according to the type of bag, and at the same time, one side forming a square bottom is linearly fused. Then, the cut film is inserted into a corresponding mold to form an arbitrary bottom shape according to the type of the bag, and after forming a fold at a square bottom, the linearly fused portion is removed. A method for producing a synthetic resin square bottom bag, wherein the bag is fused again from above in a belt shape. 2. A tube-shaped synthetic resin film is provided with gusset folds at the left and right edges to be folded and cut into arbitrary dimensions according to the type of bag, and at the same time, one side forming a square bottom is linearly fused. Then, the cut film is inserted into a corresponding mold to form an arbitrary bottom shape according to the type of the bag, and after forming a fold at a square bottom, the linearly fused portion is removed. A synthetic resin square bottom bag manufactured by re-fusing in a belt shape from above. 3. A synthetic resin square bottom bag comprising a synthetic resin square bottom bag having only a band-like fusion line at the center of the bottom surface.