JPH0576320U - Corner bottom bag - Google Patents

Abstract

(57) [Summary] [Structure] In a bag in which the bottom fusion line for horizontally fusing the bottom and the corner bottom is formed by diagonal corner bottom fusion lines, the corner bottom fusion line is the inner edge of the fold. A square bottom bag, which is provided so as to be bent vertically in the vicinity thereof so as not to contact the inner edge of the fold and to be connected to the horizontal bottom fusion line. [Effect] The square bottom bag of the present invention is a convenient and strong plastic square bottom bag that can be efficiently and easily manufactured, and has a rectangular parallelepiped shape, for example, a box, a can, especially petroleum. It is convenient because it can be used for packaging cans with a square bottom like cans.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a plastic square bottom bag.

[0002]

[Prior Art]

 Square bottom bags made of plastic sheets are very widely used for packaging rectangular solid items. These square-bottom bags are manufactured by a continuous bag-making process using a long film material as a material.However, the upper film is cut to form an opening and the lower film is formed into a square-bottom structure. With respect to the flow of material in the vertical direction, the bag is manufactured by vertically setting the upper and lower sides of the bag parallel to the flow of the material.Therefore, the opening of the bag is cut perpendicular to the flow to form The structure is such that the edges are fused by fusing. Usually, the upper part of this type of square bottom bag is simply opened by cutting a tube-shaped raw material. It is often practiced to fold the film into a seal and seal it. When a square bottom structure is provided on such a vertical bag, a casette fold is provided on the left and right edges of the tube-shaped long film stock, and the left and right sides and the front and back sides formed by the left and right gusset folds are formed. The four pairs of folds are provided with a fusion line at an angle of 45 degrees from the outer edge to the inner edge of the fold, and each fold is fixed, and the bottom of the fusion line is fused to form the bottom. It is known to form a bottom. However, the bottom surface of the known square-bottom bag has a structure as shown in FIG. 8, but when a load is put and gravity is applied to the bottom surface, the tip point D of the bottom-bottomed corner fusion line of FIG. There was a drawback that the power was concentrated on the area where it was easily damaged. Further, in the case of manufacturing a square bottom bag having a square bottom surface, as shown in FIG. 7, the fusion line is concentrated in the center to weaken the strength and the manufacturing process itself is substantially impossible.

[0003]

[Problems to be solved by the device]

 An object of the present invention is to provide a plastic square-bottom bag having improved corner-bottom strength.

[0004]

[Means for Solving the Problems]

 The present inventor has observed that when a heavy object is put in the square-bottom bag and suspended, and the number of stored items is gradually increased, the square-bottom bag is broken from the intersection of the corner-bottom fusion line and the bottom fusion line. .. Therefore, the idea is to distribute the force concentrated at the intersection of these two fusion lines, and bend the slope of the square bottom fusion line in the vertical direction near the bottom fusion line to form the bottom fusion line. In addition, the purpose of the present invention was achieved by dispersing the gravity by making the corner bottom fusion lines intersect almost vertically.

That is, according to the present invention, gusset folds are provided on the left and right of a long tubular thermoplastic plastic film stock, and four pairs of folds formed by the gusset folds are moved downward from the outer edge to the inner edge of the fold. In a corner bottom bag in which a bottom fusion line is formed by fixing each pair of folds by four corner bottom fusion lines that are inclined at 45 degrees, and then horizontally fusing the bottom of the bottom fusion line. There is provided a corner bottom bag characterized in that the corner bottom fusion line is curved in a vertical direction near the inner edge of the fold and is provided so as to be connected to the bottom fusion line without contacting the inner edge of the fold. It is a thing.

The present invention will be described in detail with reference to the drawings of the embodiments. The plastic square bottom bag shown in FIGS. 1, 2 and 3 is a tubular film provided with a square bottom structure on the bottom thereof. While pulling out the tube-shaped film original fabric into the bag making process, the tube-shaped film original fabric is gusset-folded to form four folds 1, 2, 3 and 4 so as to obtain the sectional structure of FIG. Insert a metal plate between the right gusset folds 1 and 2 and between the left gusset folds 3 and 4 and apply hot blades from the front and back of the gusset folds 1, 2, 3 and 4 to the corner bottoms. The fusing lines 5 and 6 and the two corner bottom fusing lines on the back side of each are formed to fix the folds. The corner bottom fusion line is provided on a line that inclines downward at an angle of 45 degrees from the side edges 9 and 10 of the fold toward the inner edges 11 and 12 of the fold, and is curved vertically near the inner edge. Do not touch the inner edge.

Next, a bottom fusion seal 7 is provided under the corner bottom fusion lines 5 and 6, and the four films of the gusset fold and the two films of the center are fused and fixed by this heat sealing. .. The bag manufactured in this way becomes a bag having the bottom view of FIG. As shown in FIG. 1, the corner bottom fusion lines 5 and 6 are vertically curved near the inner edges 11 and 12 of the folds 1 and 3 and intersect at a right angle toward the bottom fusion line 7. , Not connected to the inner edges 11 and 12 of the fold. When the shape of the square-bottom bag thus manufactured is inflated to form a rectangular parallelepiped, the bottom surface of the square-bottom bag is as shown in FIG.

The corner-bottom fusion lines 5 and 6 and the corner-bottom fusion lines 5 ′ and 6 ′ at the creases 2 and 4 on the back surface of each of them are as shown in FIG. Similarly, in the bottom view, the tips of 6 and 6'are smoothly linearly connected and have a gentle convex shape, so the force applied here is dispersed, so there is no damage from this part. .. The embodiments shown in FIGS. 4, 5 and 6 utilize the features of the present invention more effectively.

As shown in the sectional view of FIG. 5, this embodiment is different from the previous embodiment in that the gusset fold is folded up to the center of the tube-shaped original fabric. When the corner bottom having such a square bottom surface is fused by the conventional method, as shown in FIG. 7, the fusion line is concentrated in the center, and the strength of this center portion is extremely lowered. In the case of the present embodiment, the bottom surface is as shown in FIG. 6, the corner bottom fusion line is not concentrated as in FIG. 7, and a bag having the same strength as the rectangular parallelepiped bag can be obtained.

[0010]

[Effect of the device]

 INDUSTRIAL APPLICABILITY The present invention makes it possible to efficiently and easily manufacture a plastic square bottom bag which is convenient to use, and has a rectangular parallelepiped shape, for example, a box, a can, especially a bottom surface such as an oil can. Is convenient for packaging square cans.

[0011]

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of a square bottom bag according to the present invention.

[0012]

2 is a cross-sectional view of a tubular film having left and right gusset folds used in the embodiment of the square bottom bag of the present invention shown in FIG. 1;

[0013]

FIG. 3 is a bottom view of the square bottom bag of the present invention when it is formed into a square bottom shape.

[0014]

FIG. 4 is a front view of a square bottom bag according to another embodiment of the present invention.

[0015]

FIG. 5 is a cross-sectional view of a tubular film provided with gusset folds on the left and right, which is used in the embodiment of FIG. 4 of the present invention.

[0016]

FIG. 6 is a bottom view of the square bottom bag of FIG. 4 when used.

[0017]

FIG. 7 is a bottom view of a square bottom bag according to a conventional method.

[0018]

[Explanation of symbols]

 1 Fold 2 Fold 3 Fold 4 Fold 5 Corner bottom fusion line 5'Corner bottom fusion line 6 Corner bottom fusion line 6'Corner bottom fusion line 7 Bottom edge fusion part 8 Cutting line 9 Fold outer edge 10 Fold outer edge 11 Inner edge of fold 12 Inner edge of fold A Corner bottom surface B Corner bottom fusion line curved section C Corner bottom fusion curve section

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[Procedure amendment]

[Submission date] April 16, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Figure 8

[Correction method] Added

[Correction content]

FIG. 8 is a bottom view of a known square bottom bag.

Claims (2)

[Scope of utility model registration request] 1. A gazette fold is provided on the left and right of a long tube-shaped thermoplastic film stock, and the four pairs of folds formed by the gusset fold are inclined downward by about 45 degrees from the outer edge to the inner edge of the fold. The four corner bottom fusion lines are used to fix each pair of folds, and then the bottom fusion line is formed by horizontally fusing the bottoms of the corner bottom fusion lines. A square bottom bag characterized in that the tie line is curved in the vertical direction near the inner edge of the fold and is provided so as to be connected to the bottom fusion line without contacting the inner edge of the fold. 2. The square bottom bag according to claim 1, wherein the bottom surface is square.