JPS6013791Y2 - bag structure - Google Patents

Description

[Detailed description of the invention] This invention is a bag for sealing powdery materials, granular materials, etc., and has unique advantages not only for the time of the packer, but also for manufacturing the bag itself, and for transportation after storage. The present invention relates to an effective bag structure.

Normally, the process of packing cement into bags is as shown in Figure 1.
Using a bag having an opening a at one end of the upper part, a nozzle for spouting cement is inserted through the opening a, and after a certain amount of cement automatically flows in, the bag is sealed and carried out.

Bags used for such work must be breathable.

In other words, gas such as air flows in from the nozzle C together with the cement, but sealing this gas creates an unnecessary space between the bag and the contents, and the bag exceeds the actual storage volume. The bag expands and is not only inconvenient for loading and transporting, but also tends to damage the bag itself.

Therefore, in consideration of this point, bags for export of this type of cement, etc., have traditionally been made of six layers of kraft paper.

Paper members such as kraft paper are highly breathable and do not allow gas to be sealed together with the contents, making them the most suitable material for this type of bag.

However, the kraft paper also has many drawbacks.

First, its excellent breathability also means that it has extremely low moisture resistance.

This is a fatal drawback for cement bags that react sensitively to moisture and the like.

Furthermore, since the member is made of paper, it is undeniable that it has extremely weak water resistance and is inferior to synthetic resin sheets in terms of overall strength.

A bag with a structure shown in FIG. 2a was devised to eliminate the drawbacks of the kraft paper bag and to enhance its moisture and water resistance.

To explain this based on the drawings, d is kraft paper located inside the bag and is composed of a single sheet.

e is a synthetic resin sheet, which is joined to the craft paper d in longitudinal lines at appropriate intervals.

Regarding the effects of the bag made of the above double structure,
Since the outermost layer is made of a breathable synthetic resin sheet, it is moisture and water resistant, and can completely protect the contents such as cement from moisture and water. The disadvantages of the previous bag can be eliminated.

However, this bag body whose outside is made of an air-impermeable synthetic resin sheet has new difficulties and problems when packing cement, etc., into which gases such as air are mixed during bagging work, when making bags, and when transporting them. There are points that need improvement.

First, the air stored together with the cement in the packer passes through the air-permeable kraft paper and fills the space between the kraft paper d and the sheet 10 (see Figure 2).This air rises and finally is discharged from the bag through the perforations in the upper part, but in the packer, as shown in Figure 2, the synthetic resin sheet is removed by air pressure due to the difference in elongation rate caused by the difference in material from the kraft paper d1 sheet e. Since e is expanded, a large-diameter space is formed in d and e, and the internal pressure of that space is lowered, and the internal pressure for expelling air to the outside of the bag is lowered, causing unnecessary air to remain. In addition, the biggest drawback of this type of cement bag cannot be solved, and the bag as a whole expands beyond its actual volume, which is inconvenient for transportation.

In addition, during bag manufacturing, special adhesives must be used to bond the kraft paper, which is a paper material, and the sheet, which is a synthetic resin, and the manufacturing cost of the bag is inevitably high. It has the following disadvantages.

The present invention eliminates all the drawbacks of the bag made of the double structure of kraft paper and synthetic resin sheets, and is extremely useful for packing, transporting, and making bags for powdery and granular materials. The purpose is to provide a bag structure.

The structure of the present invention is that gas is mixed with the contents when stored, and the inner bag part is made of paper and the outer bag part is made of a synthetic resin sheet, and gas discharge parts such as perforations are formed locally. In the bag body, paper is integrally bonded to the inner periphery of the synthetic resin sheet, and the paper portion of the inner periphery of the outer bag and the outer periphery of the inner bag are bonded linearly at intervals to form a space. It relates to a bag structure characterized by
This will be explained below based on an embodiment shown in the drawings.

In FIG. 3a, numeral 1 denotes an inner bag, which is made of kraft paper in this embodiment, and is located at the innermost layer of the bag body of the present invention.

Reference numeral 2 denotes a paper material that is integrally fused to the inner circumference of a synthetic resin sheet 3 to be described later to form an outer bag, and in this embodiment, the inner bag 2
Craft paper is used as well, and the synthetic resin sheet 3 is melt laminated, and the inner bag 1 is lined with adhesive 4 at regular intervals in the longitudinal direction.
etc. to form a space portion 5.

The synthetic resin sheet forming the outer bag together with the paper material 2 is
In this example, it is cloth, and as mentioned above, the kraft paper 2
It is melt laminated and inseparable from the other parts.

In this embodiment having the above configuration, the outer shape is the first
It has the same shape as the bag shown in the figure and is packed in the same process.

That is, air is mixed with cement into the bag by the nozzle C through the opening a.

Due to the high pressure generated by the inflow of the contents from the nozzle and the sealing, this air passes through the breathable kraft paper 1 without staying inside the bag, and fills the space formed between the inner bag 1 and the paper material 2. Moving to part 5, the paper material 2 is still compressed by the pressure inside the bag.

However, the paper material 2 is an air-impermeable synthetic resin sheet 3.
Since it is integrated with the paper material 2, air cannot pass through the paper material 2, and the elastic synthetic resin sheet 3 (cloth in this example) is integrated with the kraft paper, which has an extremely low elongation rate. Therefore, the pressure in the waist space is kept high compared to the previous row described above without almost inflating, and the air moves upward or downward and is easily discharged from the perforations of the sutured area.

As explained above, in this invention, the triple structure of kraft paper, which is the inner bag constituent material, kraft paper, which is the outer bag constituent material, and cloth, and the outer bag is stretchable and breathable. The advantages and disadvantages of both materials are compensated for by melt-laminating cloth with no elasticity and kraft paper with extensibility and breathability, which have completely different properties.
Therefore, it has an extremely low elongation rate and high moisture and water resistance.
Moreover, it has exhaust properties and has all the properties necessary for this type of bag.

In the case of the packer, even under the pressure of air flowing in with the contents, the cloth integrally molded with the kraft paper does not stretch and maintains high pressure inside the bag, allowing the bag to maintain high pressure at the seam points of the bag. is smoothly discharged through the
The inner bag will not be damaged due to the difference in the degree of elongation between the inner bag and the outer bag, and unnecessary space will not be formed inside the bag, allowing it to be used for bag filling.

When transporting the packed contents, as mentioned above, there is no risk of damage to the inner bag, and it also prevents the contents from getting mixed in due to damage to the inner bag, and has excellent overall impact resistance. The structure is a three-layer structure containing two sheets of kraft paper, so the bag will not bend or deform even when containing powdery or granular materials that do not have a regular shape, especially when transported one bag at a time by hand. It is easy to maintain, and when stored, the outermost layer is made of synthetic resin that is moisture and water resistant, so it can be stored safely for a long period of time, even if the contents are subject to chemical changes due to moisture, such as cement, which reduces commercial value. It can be stored for a long time.

Furthermore, in the conventional bag making process, two members made of different materials and having different elongation rates are put through the bag making machine, which results in uneven edges, which seriously impedes the cutting or folding process. In the invention, the synthetic resin sheet used as the outer bag material has limited elongation, so this drawback does not occur and the bag-setting process and bag-making work can be carried out in an orderly and stable manner.

Furthermore, since the adhesive part that is bonded with the adhesive 4 etc. is a bond between kraft papers, it can be used to bond ordinary paper without using a special expensive adhesive like the conventional bonding of synthetic resin and kraft paper. The adhesive used has a sufficiently strong adhesive effect, and it can be manufactured at a low cost, and even when many bags are stacked on top of each other in the final manufacturing process, the present invention avoids the triple structure. They have a regular shape and can be stacked neatly, and can also be folded neatly.

As described above, the present invention has many effects during transportation after temporary storage of the packer, during storage, and even during bag making.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a packer, FIG. 2 a is a partially sectional perspective view showing a conventional example, FIG. 2 is a sectional view showing a conventional example, and FIG. FIG. 3 is a partially sectional perspective view showing an embodiment of the present invention. FIG. a...Opening, b...Bag body, C...Curved nozzle, d...Craft paper, e...Synthetic resin sheet, 1. ...Inner bag, 2...
Paper material, 3. Curved resin sheet, 4. Adhesive, 5. Space.

Claims (1)

[Scope of utility model registration request] In a bag body in which gas is mixed with the contents during storage, the inner bag portion is made of paper, the outer bag portion is made of a synthetic resin sheet, and gas discharge portions such as perforations are formed on the periphery.
Paper is integrally bonded to the inner periphery of the synthetic resin sheet, and the paper portion of the inner periphery of the outer bag and the outer periphery of the inner bag are bonded linearly at intervals to form a space. Characteristic bag structure.