JP6362975B2 - Industrial bag inner bag and industrial bag - Google Patents

Description

  The present invention relates to an inner bag of an industrial bag and an industrial bag.

  In recent years, flexible container bags and sandbags have been used to transport and store raw materials, products, and earth and sand in various fields such as processed foods, feeds, industrial raw materials, synthetic resins, medicine, agriculture, and construction industries. . Flexible container bags and sandbags are light and inexpensive, and have the advantage of good transport efficiency because they can be folded and transported when not in use. These flexible container bags and sandbag bags are called industrial bags.

  Flexible container bags and sandbags have a double structure consisting of an outer bag and an inner bag. The inner bag accommodates the contents and plays a role of preventing the contents from scattering and leaking, and a thermoplastic resin film is used. The outer bag serves to support the weight of the inner bag, and a woven fabric of thermoplastic resin fibers is used.

JP 2003-285898 A

  When flexible container bags and sandbags are made of rubble or wood chips, the sharp parts of the contents may make holes in the inner bag, and the inner bag may be torn from the hole, causing the contents to leak. there were. In addition, when the contents are mixed with plants, the seeds sprout and break through the inner bag, or when the inner bag is made of polyethylene, there is a risk that the rot will progress and the odor will permeate the inner bag.

  Therefore, an object of the present invention is to provide a flexible container bag or an inner bag of a sandbag bag in which holes are not easily expanded and leakage of contents and odors can be suitably suppressed.

  One aspect of the present invention is an inner bag that is formed into a gusset shape and is housed in an outer bag to form an industrial bag together with the outer bag, and is an unstretched polyamide film / metal / polyethylene in order from the outer side of the inner bag. The tensile breaking elongation in the depth direction and the width direction perpendicular to the depth direction from the opening to the bottom is 200% or more and 1000% or less.

  The inner bag is formed of a plurality of films, and at least one of the plurality of films may have a layer configuration of unstretched nylon / aluminum / linear low density polyethylene.

  Another aspect of the present invention is a flexible container bag or a sandbag bag including the above-described inner bag and an outer bag containing the inner bag.

  ADVANTAGE OF THE INVENTION According to this invention, it can provide the inner bag of the industrial bag which has sufficient tensile fracture | rupture elongation and tear strength, and a hole cannot expand easily and can suppress leak of the content and an odor suitably. Moreover, by providing a metal layer, dead hold property improves and it is easy to perform a filling operation.

The perspective view of the industrial bag which concerns on one Embodiment of this invention. The figure which shows the manufacturing method of the inner bag of the industrial bag which concerns on one Embodiment of this invention. The figure which shows the layer structure of the film of the inner bag of the industrial bag which concerns on one Embodiment of this invention.

(Embodiment)
In FIG. 1, the perspective view of the industrial bag 300 which concerns on this embodiment is shown. The industrial bag 300 includes an outer bag 200 and an inner bag 100 accommodated therein. FIG. 2 shows a method for manufacturing the inner bag 100. As an example, the inner bag 100 is formed by stacking four films 101 as shown in FIG. 2, sealing each peripheral edge except for a portion that becomes an opening, and folding the bottom to form a gusset. Made in a bag.

  FIG. 3 shows the layer structure of the film 101. The film 101 has a layer structure of unstretched nylon / aluminum / linear low density polyethylene in order from the outer side of the inner bag 100. As an example, the depth direction from the opening of the inner bag 100 toward the bottom coincides with the MD direction (Machine Direction) of the film 101, and the width direction perpendicular to the depth direction coincides with the TD direction (Transverse Direction). .

  Although the size of the inner bag 100 is not limited, for example, it is possible to form a gusset using four films 101 of 3 m × 1 m, and fold the bottom part by about 1 m to form a cubic shape with a side of 1 m.

  The film 101 is made of unstretched nylon and has a certain puncture strength, and it is difficult to open a hole even with sharp contents. Further, when the film 101 is pulled, the inner aluminum layer is not stretched and is torn at various places, and the unstretched nylon layer and the linear low-density polyethylene layer are peeled off from the aluminum layer at the torn locations. . Therefore, the unstretched nylon layer and the linear low-density polyethylene layer are partially separated from each other, and the stretching of the linear low-density polyethylene layer is less likely to be suppressed by the unstretched nylon layer that is harder to stretch. The tensile elongation at break of the film 101 as a whole increases. Along with this, the tear strength also increases. The film 101 preferably has a tensile breaking elongation in the MD and TD directions of 200% to 1000% by appropriately setting the thickness of each layer. By setting the tensile elongation at break to 200% or more, sufficient elongation at break can be obtained, and even if a hole is opened, it is difficult to expand, and leakage of contents can be suppressed. By setting the tensile elongation at break to 400% or more, the holes are more difficult to expand, which is more preferable. Moreover, by setting the tensile elongation at break to 1000% or less, it is possible to prevent the inner bag 100 from extending too much and the weight of the contents directly on the outer bag 200 and tearing the outer bag 200.

  Since the film 101 includes an aluminum layer that does not easily transmit odor or the like, the odor can be prevented from leaking even when the contents are spoiled. In addition, since the aluminum layer hardly transmits light, even if the contents contain plants, the aluminum layer can suppress the photosynthesis of the plants and prevent the grown plants from breaking through the film 101.

  The layer configuration of the film 101 is not limited to the above example as long as it is a layer configuration of unstretched resin (for example, polyamide) film / metal / polyethylene in order from the outside of the inner bag 100. For example, unstretched polypropylene, unstretched EVOH resin (ethylene / vinyl alcohol copolymer resin), or the like may be used as the unstretched resin film. The innermost layer may be polypropylene instead of polyethylene. Moreover, the inner bag 100 does not need to be formed by the above-mentioned method, if such a film 101 is used for at least one part.

  The outer bag 200 can be made of a thermoplastic resin fiber such as polyolefin resin, polyvinyl chloride, polyester, polyvinyl alcohol, or polystyrene. Examples of polyolefin resins include high-density polyethylene, medium-density polyethylene, linear low-density polyethylene, ethylene-α olefin copolymer, polypropylene, polybutene-1, and ethylene-vinyl acetate copolymer obtained using a metallocene catalyst. Polyethylene terephthalate and polybutylene terephthalate can be used as the polyester. The outer bag 200 can be formed using a flat yarn obtained by slitting and stretching a film made of these materials, or a monofilament obtained by stretching a filament extruded from a spinning nozzle.

The following examples and comparative examples of the present invention will be described.
Example 1
A gusset was formed using four films of 3 m × 1 m, and the bottom part was folded by about 1 m to form a cube-shaped inner bag having a side of 1 m. The depth direction from the opening of the inner bag toward the bottom was matched with the MD direction of the film, and the width direction perpendicular to the depth direction was matched with the TD direction. The layer structure of the film was unstretched nylon (30 μm) / aluminum (9 μm) / linear low density polyethylene (70 μm). The outer bag was formed using polypropylene.

(Example 2)
The difference from Example 1 is that the layer structure of the film is unstretched nylon (30 μm) / aluminum (9 μm) / linear low-density polyethylene (100 μm).

(Example 3)
The difference from Example 1 is that the layer structure of the film is unstretched nylon (50 μm) / aluminum (9 μm) / linear low-density polyethylene (100 μm).

(Comparative Example 1)
The layer structure of the film is different from that of Example 1 only in that the layered polyethylene terephthalate (12 μm) / aluminum (9 μm) / stretched nylon (15 μm) / linear low density polyethylene (70 μm) is used.

(Comparative Example 2)
The layer structure of the film differs from that of Example 1 only in that the aluminum vapor-deposited polyethylene terephthalate (12 μm) / stretched polypropylene (30 μm) / unstretched nylon (30 μm) / linear low-density polyethylene (70 μm).

(Comparative Example 3)
The layer structure of the film is different from Example 1 only in that unstretched nylon (20 μm) / aluminum (9 μm) / unstretched nylon (20 μm) / linear low density polyethylene (80 μm).

The following evaluation was performed about the above Example and the comparative example.
(Evaluation 1) 1.5 tons of earth and sand and crushed stone were enclosed in a flexible container bag, allowed to fall freely from a height of 80 cm, and visually checked for tearing of the inner bag.
(Evaluation 2) The tensile elongation at break of the film of the inner bag was measured in the MD direction and the TD direction based on the tensile strength test standard of JIS Z 1707 according to JIS K 7127.
(Evaluation 3) The tear strength of the film of the inner bag was measured in the MD direction and the TD direction in accordance with the tear strength test standard of JIS K 7128-1.
Table 1 below shows the evaluation results.

In (Evaluation 1), in Examples 1 to 3 and Comparative Example 3, it was confirmed that the film of the inner bag was not torn. In Comparative Examples 1 and 2, holes were opened in portions other than the seal portion between the films and the seal portion, and the film was torn from there.
In (Evaluation 2), in Examples 1 to 3 and Comparative Example 3, a tensile breaking elongation of 200% or more was confirmed in both the MD direction and the TD direction. In Examples 1 to 3, a tensile breaking elongation of 400% or more was confirmed in both the MD direction and the TD direction. In Comparative Examples 1 and 2, the tensile breaking elongation was less than 200% in both the MD direction and the TD direction.
In (Evaluation 3), in Examples 1 to 3, a tear strength of 10 N or more was confirmed in both the MD direction and the TD direction. In Comparative Examples 1 to 3, the tensile breaking elongation was less than 3N in both the MD direction and the TD direction.

  From the above, it was confirmed that in Examples 1 to 3, the tensile elongation at break and tear strength were larger than those in Comparative Examples 1 to 3, and the film was not actually easily torn.

  In Comparative Example 3, the tensile elongation at break was larger than those in Comparative Examples 1 and 2, and in (Evaluation 1), the film did not break, but the tear strength was much smaller than in Examples 1 to 3. When the drop test is performed under conditions more severe than (Evaluation 1), the film may be torn. This is because even if the film of Comparative Example 3 is pulled and the inner aluminum layer is torn, the unstretched nylon layer between the aluminum layer and the linear low density polyethylene layer is peeled off from the linear low density polyethylene layer. Therefore, the stretching of the linear low-density polyethylene layer is suppressed by the unstretched nylon layer that is harder to stretch than this, and the tensile breaking elongation does not increase so much as the whole film, so that it is considered that the tear strength does not increase.

  As described above, according to the present invention, it is possible to provide an inner bag of a flexible container bag that has sufficient tensile elongation at break and tear strength and is capable of suitably suppressing the leakage of contents and odors that are difficult to expand the hole. it can.

  The present invention is useful for flexible container bags, sandbag bags, and the like.

100 Inner bag 101 Film 200 Outer bag 300 Industrial bag

Claims (3)

An inner bag that is made in a gusset shape and is housed in an outer bag to constitute an industrial bag together with the outer bag,
Tensile rupture in the depth direction from the opening to the bottom and in the width direction perpendicular to the depth direction, formed using an unstretched polyamide film / metal / polyethylene layer structure in order from the outside of the inner bag An inner bag having an elongation of 200% or more and 1000% or less.   2. The inner bag according to claim 1, wherein the inner bag is formed of a plurality of the films, and at least one of the plurality of films has a layer configuration of unstretched nylon / aluminum / linear low density polyethylene. .   An industrial bag provided with the inner bag of Claim 1 or 2, and the outer bag which accommodated the said inner bag.

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