JP2000142729A - Granule bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity by providing an intermittent part on a portion of a fused seal of a bag, forming a vent connected from the inside to the outside of the bag and making synthetic resin films on a surface and a rear face at the vent protrude respectively upward and downward from a plane formed by a fused seal line. SOLUTION: A tubelike synthetic resin film 2 is fuse-sealed 3 with an intermittent part 3 left on a bottom to form a vent 4. Synthetic resin films on a surface and a rear face constituting the vent part 4 are made to protrude respectively from a plane formed by a fused seal line 3 thereby keeping a cross-sectional area of the vent 4 large. Therefore the cross-sectional area of the vent 4 can be increased, thereby increasing air discharging speed. In addition even if tension is applied to the part by a weight of contents when the bag is filled with granules, the vent 4 may not be closed. Thus air discharging speed can be increased, and also the bag can be used for high speed automatic packaging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to cereals such as rice and wheat,
The present invention relates to a bag for packing granular materials such as fertilizers and feeds, and more particularly, to a bag in which residual air in a bag is easily discharged when stacked after a packaging operation.

[0002]

2. Description of the Related Art Conventionally, bags formed of a synthetic resin film have been used for packaging grains such as rice and wheat, fertilizers, feedstuffs and the like. In such a plastic bag,
When the contents are filled and the filling port is sealed, air remains inside the bag. Therefore, there is a problem that the volume occupied by the bag becomes enormous, a large storage space is required, and storage efficiency is reduced. In addition, when a large number of bags are stacked, there is a problem that the pressure in the bags increases due to the weight, the bags are broken, contents are spilled out, and above all, the stacked bags are easily broken and dangerous.

As a means for solving such a problem, there has been proposed a bag in which many small holes are perforated on the entire surface of the bag.
However, this type of bag has a drawback that the air discharging speed is low because the air is discharged through a small hole. Furthermore, if the size of the hole is increased to increase the air discharge speed, the strength of the bag will decrease, the contents will spill,
There is a problem that insects and foreign matter are mixed. on the other hand,
A bag has been proposed in which a non-welded portion in a flat state is simply left on a part of a seal line forming the outer periphery of the bag to serve as a vent.
However, in the bag of this form, the non-welded portion (vent) provided on a part of the seal line forming the outer periphery of the bag is easy to adhere, and when the contents are filled, the vicinity of the vent near the vent depends on the weight of the contents. There is a problem in that the base material tends to be tensioned, and the ventilation holes are liable to be closed, the air discharge speed is low, and it is not suitable for high-speed automatic filling.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a bag which has a high air discharging speed and can be used for high-speed automatic packaging.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies. As a result, a bag in which the above-mentioned problem is solved can be obtained by devising the cross-sectional shape of the vent in the bag having the non-welded portion left in a part of the seal line forming the outer periphery of the bag and serving as the vent. The present invention has been found. That is, according to the present invention, a bag formed by melt-sealing the vicinity of an edge of a synthetic resin film, wherein the melt-sealed portion of the bag has a partly intermittent portion, so that a vent opening from the inside of the bag to the outside of the bag. Is formed, and the synthetic resin film on the front and back at the vent portion is vertically convex with respect to the plane formed by the fusion seal line.

[0006] Further, there is provided the bag for granular material as described above, wherein the cross-sectional area of the vent is gradually reduced from the inside of the bag toward the outside of the bag.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail. The bag for granular material of the present invention is manufactured using a flat film or a tube-like film in which the side serving as the bag inner surface is a synthetic resin layer that can be melt-sealed when the bag is manufactured. This film may have a single-layer structure or a multilayer structure. When a film having a multilayer structure is used, it may have a layer other than a synthetic resin, such as paper, nonwoven fabric, and metal cloth. Hereinafter, these films are collectively referred to as synthetic resin films.

[0008] The bag for granular material according to the first embodiment of the present invention is formed by melting and sealing the above-mentioned synthetic resin film, and furthermore, an intermittent portion is formed on the molten sealing line generated by the fusion sealing. Is provided to form a ventilation hole, and the synthetic resin films on the front and back sides of the ventilation hole portion are formed so as to project upward and downward, respectively, with respect to a plane formed by the fusion seal line. With such a structure of the vent, the cross-sectional area of the vent can be increased, and the air discharge speed is increased. Furthermore, when the granular material is filled, even if tension is applied to this portion by the weight of the content, the vent hole is not blocked. FIG. 1 and FIG. 2 are a schematic front view and a schematic partial perspective view, respectively, showing the form of the granular material bag of the present invention. FIG. 3 is an enlarged view of a main part of FIG. FIG. 4 is a schematic sectional view showing a part of a section taken along line AA ′ of FIG. From these figures, it can be seen that the tube-shaped synthetic resin film 2 is melt-sealed 3 while leaving the intermittent portion 3 at the bottom to form the vent 4, and the front and back synthetic resin films constituting the vent 4 are melted. It can be seen that each of the projections is convex with respect to the plane formed by the seal wire 3 and the cross-sectional area of the ventilation port 4 is kept large. As a result, when the bags are filled with the particulate matter and the bags are stacked, the residual air in the bags is easily discharged. In these figures, a bag for granular material obtained when a tubular film is used is assumed, but the present invention can also be applied to a bag made from a flat film including the second embodiment described below. . Further, the vent may be provided in the melt seal portion at the bottom of the bag, or in the melt seal portion on the side surface of the bag, or in the melt seal portion formed for sealing after filling the contents into the bag. Alternatively, it may be provided at a plurality of sites.

Next, a second embodiment of the present invention will be described. The present embodiment is characterized in that the cross-sectional area of the vent of the first embodiment is formed so as to gradually decrease from the inside of the bag toward the outside of the bag. FIG. 5 is a schematic perspective view showing a main part of the granular material bag formed in such a structure. Compared to the first embodiment of the present invention shown in FIG. 3, it can be seen that the cross-sectional area of the vent is formed so as to gradually decrease from the inside of the bag toward the outside of the bag. The granular material bag of this embodiment can effectively prevent moisture, pests, foreign matter, and the like from entering from the outside of the bag while maintaining a high air discharge speed.

Next, a method of manufacturing the bag for granular material of the present invention will be described. In order to obtain the granular material bag of the present invention, at least one pair of grooves having an intake port connected to a decompression device are provided at positions opposite to the upper and lower seal bars used when melt-sealing the synthetic resin film. deep. This groove is for forming a vent in the fusion seal portion of the present invention.
Therefore, it must be processed so as to form a vent that extends from the inside to the outside of the obtained particulate bag. FIG. 6 is a schematic perspective view showing a part of the seal bar processed in this manner, and is used to make the above-mentioned granular material bag of the first embodiment. A groove 6 is formed in a direction perpendicular to the longitudinal direction of the seal bar 5, and a suction port 7 is provided at the bottom thereof, and is connected to a suction device (not shown). It should be noted that the shape of the groove 6 is not limited to the shape shown in the drawing, and the shape and number of the intake ports 7 are not limited.

On the other hand, FIG. 7 is a schematic perspective view showing the shape of a seal bar used for making the above-mentioned granular material bag according to the second embodiment. The feature of this seal bar 5 is that the depth d2 of the groove 6 on the side corresponding to the outside of the bag (downward in the drawing) is
Depth d of groove 6 on the side (upper drawing) corresponding to the inside of the bag
It is processed shallower than 1. Since the seal bar 5 has such a structure, the shape of the groove 6 is transferred to the synthetic resin film 2 and a bag as in the second embodiment of the present invention is obtained.

A synthetic resin film is formed into a bag using a fusion sealing device provided with a seal bar having the above-described structure. At the time of bag making, at least a certain period of time during which the upper and lower seal bars are closed and the melt sealing is being performed, the reduced-pressure suction is performed from the above-described intake port. As a result of this reduced pressure suction, the front and back synthetic resin films located in this portion are sucked into the grooves formed in the upper and lower seal bars, so that the front and back synthetic resin films are not welded to each other in this portion, and the ventilation port is opened. It is formed. Also, in this step, the synthetic resin film corresponding to the portion of the vent is heated or softened or melted by the seal bar, so after cooling, this portion is, as it were, a vacuum-formed molded article, It keeps its open shape. FIG. 8 is a partial schematic cross-sectional view showing a state at the time of fusion sealing during bag making. As a result of the air being exhausted from the intake holes 7 in the grooves provided in the seal bar 7, the pressure in the groove is reduced, so that the upper and lower synthetic resin films 2 are attracted to the upper and lower seal bars, respectively, and the ventilation holes are formed. It can be seen that No. 4 is formed.

[0013]

As described above, according to the present invention, there is provided a bag for a granular state which has a high air discharging speed and can be used for high-speed automatic packaging.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing a first embodiment of a granular material bag according to the present invention.

FIG. 2 is a schematic partial perspective view showing a first embodiment of the granular material bag of the present invention.

FIG. 3 is an enlarged view of a main part of FIG. 2;

FIG. 4 is a schematic cross-sectional view showing a part of a cross section taken along line AA ′ of FIG. 2;

FIG. 5 is a schematic partial perspective view showing a second embodiment of the granular material bag of the present invention.

FIG. 6 is a schematic perspective view showing a part of a seal bar.

FIG. 7 is a schematic perspective view showing a part of a seal bar.

FIG. 8 is a partial schematic cross-sectional view showing a state at the time of fusion sealing during bag making processing.

[Explanation of symbols]

 1. Granular bag 2. 2. Synthetic resin film Melt seal part 4. Vent 5. Seal bar 6. Groove 7. Air intake

Claims (2)

[Claims] 1. A bag formed by melt-sealing the vicinity of an edge of a synthetic resin film, wherein the melt-sealed portion of the bag has a partly intermittent portion, thereby forming a vent opening from the inside of the bag to the outside of the bag. A bag for a granular material, wherein the synthetic resin films on the front and back sides of the vent portion are vertically convex with respect to a plane formed by a fusion seal line. 2. The bag according to claim 1, wherein the cross-sectional area of the ventilation port is formed so as to gradually decrease from the inside of the bag toward the outside of the bag.