JP2015044601A - Flexible container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible container having high strength, excellent in piercing resistance, enabling prevention of content leakage without breaking even if indeterminate form materials having protrusions are filled, excellent in handleability and transportability, and more inexpensive than a running container.SOLUTION: A flexible container comprises: an inner bag laminate formed by laminating cylindrical films having a thickness of 30-300 μm made of polyolefin as a main material at least doubly inside and outside; and an outer bag. Polyethylene or polypropylene can be used as the polyolefin. A linear low-density polyethylene having 4-8C side chains is preferable when using polyethylene. The total thickness of the inner bag laminate is set to be 100-1,000 μm. A cylindrical film of polyamide as the main material having the above thickness, or a cylindrical laminate film having the above thickness made by laminating the polyamide film and a film of polyolefin as the main materials can be included in the inner bag laminate.

Description

  The present invention relates to a flexible container used for transporting and storing powder and the like.

Currently, in a wide range of industries, flexible containers are used to transport and store various substances, such as resin pellets, chemical products, inorganic substances, minerals, grains, feeds, etc. It is used. The flexible container body basically includes a cylindrical body, an upper input part that can be sealed at the upper end of the cylindrical body, and a discharge part that can be sealed at the lower part of the cylindrical body. Are each made of a synthetic fiber cloth sheet material.

Flexible containers are classified into running containers that are assumed to be used repeatedly over a long period of time and cross containers that are premised on only one filling use or that have been set for one year. The As the former running container, a container in which polyester fiber is mainly used as a base fabric and flexible soft vinyl chloride, EVA, polyurethane, rubber or the like is laminated on both front and back surfaces is used.

On the other hand, in the latter cross container, there are a container without an inner bag depending on its contents, and a container with an inner bag inserted into the cloth container. In the case of a cross container without an inner bag, proposals have been made to prevent the leakage of powder by devising the joints between the upper part, the bottom part, and the body part (see, for example, Patent Document 1 and Patent Document 2). However, in the methods according to these proposals, since a flat yarn is used and the cloth constituting the cross container is woven by a circular loom, there is always a gap between the yarns. Since this gap is not completely filled, when the liquid is filled, the leakage of the liquid cannot be completely prevented.

In addition to the proposal in the above-mentioned patent document, there is a method of laminating a thermoplastic resin on one or both sides of the cloth constituting the cross container for the purpose of preventing leakage of contents. However, even in that case, there is a possibility of powder leakage or water leakage from the stitched portion due to the structure of the cross container. In Patent Document 3, a proposal for preventing leakage of the contents from such a stitched portion has been made. However, there is a possibility that the laminate may crack when the fabric is stitched, and the yarn fabric is a flexible material. Therefore, when force is repeatedly applied to the yarn fabric during folding work, pinholes and cracks enter the laminate, and there is concern about leakage of the contents from that part, so there is concern about using without an inner bag. It can be said.

In order to prevent leakage, it is indispensable to use a flexible container having an inner bag. By providing the inner bag in this way, it is possible to prevent leakage of contents and mixing of foreign substances during transportation and storage of powder and liquid. However, in an inner bag generally used for a flexible container today, when the contents include an irregular shape having a protrusion or the like, the inner bag breaks due to the protrusion, and the contents are There is a possibility of leakage. In particular, when the contents contain a liquid, the leakage of the liquid becomes significant due to the bag breaking of the inner bag. As a countermeasure, it is conceivable to increase the thickness of the inner bag so that the bag does not break even if pierced, but in that case, the flexibility of the inner bag is lowered, and the handling and transportability deteriorate. This is not preferable because of concern.

On the other hand, in the case of a running container as proposed in Patent Documents 4 and 5, an excellent stab resistance is provided by increasing the thickness of the fabric. However, it is also possible that the contents may ooze out from the welded portion of the fabric. In addition, the running container has a drawback of being unsuitable for applications requiring a large amount of flexible containers because mass production is difficult and expensive.

JP 2001-341792 A Utility Model Registration No. 3132871 Specification JP 2007-8508 A JP-A-2-137925 Japanese Utility Model Publication No. 6-12037

  In view of the above circumstances, the present invention has high strength and excellent puncture resistance, can prevent leakage of contents without breaking a bag even when filled with an irregular shape having protrusions and the like, and is easy to handle and transport. The purpose is to provide a flexible container that is superior in performance and cheaper than a running container.

  As a result of intensive studies to develop a flexible container capable of preventing leakage of contents with higher strength and puncture resistance than conventional products, the present inventors have obtained a film with a predetermined thickness constituting the inner bag. It was found that by laminating multiple sheets, it has physical strength such as puncture resistance superior to the inner bag made of a single film with the same thickness as the total thickness, and the present invention was completed. It came to do.

That is, according to the present invention, the object consists of an inner bag laminate formed of at least two cylindrical films having a thickness of 30 to 300 μm made of polyolefin as a main raw material, and an outer bag. Achieved by the flexible container featured. If the thickness of each film is set to 30 to 300 μm within this thickness range, it is formed into a bag-like inner bag while maintaining physical strength such as puncture resistance to some extent. Is easily inserted into the outer bag, or the opening of the cylindrical film is easily closed or opened, which is advantageous in terms of handling.

Polyethylene or polypropylene can be used as the polyolefin. When polyethylene is used, a linear low density polyethylene having 4 to 8 carbon side chains having a melt flow rate (MFR) of 0.03 to 4.0 and a specific gravity of 0.900 to 0.960 according to JIS K7210 is used. It is preferable to use it.

The blending ratio of the polyolefin in each film can be set to 20 to 100% by weight, preferably 40 to 100% by weight, and more preferably 50 to 100% by weight with respect to the whole film. Further, at least one of the tubular films may contain 0 to 40% by weight of thermoplastic polyolefin with respect to the whole film.

  The inner bag laminate is a cylindrical laminate film in which a polyamide film as a main raw material or a film having the polyolefin and a polyolefin as a main raw material are laminated, and the film thickness is 30. It may contain at least one layer in the range of ˜300 μm. Thus, by including a film mainly made of polyamide, high toughness and strength characteristics of polyamide are effectively added to the physical strength of the inner bag laminate itself.

The total thickness of the inner bag laminate is not particularly limited and can be set to an appropriate thickness, but is preferably set to be in the range of 100 to 1000 μm.

It does not specifically limit as said outer bag, A conventionally well-known thing can be used. Specifically, for example, a material formed by weaving a flat yarn having a thickness of 30 to 140 μm mainly using polyolefin as warp and weft can be used.

  Since the flexible container of the present invention is composed of an outer bag and an inner bag laminate formed by laminating at least two cylindrical films of a predetermined thickness mainly made of polyolefin, It is possible to prevent the contents from leaking without breaking the inner bag laminated body against piercing or external impact by the contents while maintaining the handleability of the body and the outer bag well. It is. Also, in order to obtain the above effect according to the type and appearance of the contents, the thickness of some or all of the at least two sheets of the inner bag laminate is changed or the number of overlaps is changed. Since it can be changed at the production line of the flexible container of the invention or at the site, it is possible to adapt to the circumstances.

  In addition, the flexible container of the present invention is inserted in an outer bag corresponding to an inexpensive ordinary cloth container, and at least two inner bags made of a film mainly made of a low-cost polyolefin as an inner bag laminate. Therefore, it can be manufactured at a lower cost than a conventionally known running container.

It is a figure which shows an example of embodiment of the flexible container of this invention. It is the figure which shows the state which isolate | separated the inner bag laminated body and outer bag of embodiment shown in FIG. 1, and demonstrates the insertion in the outer bag of an inner bag laminated body. It is a figure which shows the combination of the two cylindrical films (inner bag laminated body) of the inner bag of embodiment shown in FIG. 1, and the yarn cloth | dough of an outer bag.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram illustrating a cross container that does not include a discharge portion at the bottom as an example of an embodiment of a flexible container according to the present invention. Moreover, FIG. 2 is a figure explaining the state which isolate | separated the inner bag laminated body and the outer bag in the embodiment shown in FIG. 1, and inserting the inner bag laminated body into the outer bag. FIG. 3 is a partially enlarged view showing a combination of two cylindrical films of the inner bag laminate of the embodiment shown in FIG. 1 and a yarn fabric of the outer bag.

  As shown in FIGS. 1 to 3, the flexible container 1 of the present embodiment includes an inner bag laminate 2 in which a cylindrical film having a predetermined thickness is laminated, and an opening 53 of a charging portion 52 provided on the upper portion of the outer bag 5. It is set as the structure inserted inside.

(1) Inner bag laminate 2
The inner bag laminate 2 in the present invention is obtained by overlapping two sheets of inner bags 3 and 4 made of cylindrical films 31 and 41 made of polyolefin as a main raw material inside and outside.

Specific examples of polyolefin include polyethylene and polypropylene. When using polyethylene, low density polyethylene (LDPE) with a density in the range of 0.900 to 0.960, linear low density polyethylene
(LLDPE), high density polyethylene (HDPE), metallocene polyethylene and the like can be used. Among these, it is particularly preferable to use LLDPE having a melt flow rate (hereinafter simply referred to as MFR) in accordance with JIS K7210 of 0.03 to 4.0 g / 10 min and having a side chain of 4 to 8 carbon atoms. . Such LLDPE can be produced by adding α-olefin having 4 to 8 carbon atoms such as butene-1, hexene-1, 4 methylpentene-1, and octene-1 at the time of production. Moreover, when using polypropylene, the thing of MFR0.1-2.0 etc. can be used conveniently. As polyolefin, polypropylene and the said polyethylene can also be combined.

  The tubular film 31 (or 41) may be formed of a polyolefin alone, and may contain other resins and various additives as necessary. The content ratio of polyolefin in the films 31 and 41 is preferably set to 20 to 100% by weight when the entire film 31 (or 41) is 100% by weight. This is because when the blending ratio of the polyolefin is less than 20% by weight, it is difficult for the inner bag laminate to maintain physical strength such as puncture resistance.

  The raw materials for the films 3 and 4 may further contain a resin (modifier) such as an olefinic thermoplastic elastomer (TPO). TPO is an elastomer (rubber, such as polypropylene, hard segment, and polyethylene, an elastomer having a small amount of ethylene and a diene component, ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber (EPR), styrene elastomer). ) Is a soft segment, and these are obtained by simply kneading and blending them mechanically. Further, those obtained by adding an organic peroxide to the soft segment and partially crosslinked, and those obtained by graft-modifying the soft segment with an unsaturated hydroxy monomer or an unsaturated carboxylic acid derivative are also included. These various thermoplastic elastomers can be used alone or in combination of two or more.

  The content ratio of TPO is preferably set to 0 to 40% by weight when the entire inner bag 3 or 4 (tubular film 31 or 41) is 100% by weight. This is because when the content ratio of TPO exceeds 40% by weight, physical strength is deteriorated in puncture resistance and the like.

  In the raw material of the film 31 (or 41), for the purpose of further modifying the film, additives such as a weather resistance agent, an antistatic agent, an antioxidant and the like are added as necessary without affecting the properties of the film. Can be added.

  The raw material thus prepared is put into a heated cylinder from a hopper of an inflation molding machine, sent with a screw while being kneaded in a completely molten state, passed through an annular die, and blown air from its lip portion. It is extruded into a cylindrical shape, cooled with an air ring, pulled up with a pinch roll, and continuously formed into a polyethylene raw material (cylindrical film) in a crushed state. The blow ratio by air blowing at this time is an important factor for determining the orientation balance of the film, and is preferably set to 1.0 to 3.0.

  Further, as a method for forming the film into a cylindrical shape, for example, the film is first formed into a film by a conventionally known T-die forming method, calendar forming method or stretching method, and then the both ends in the length direction or width direction of the film are formed. You may shape | mold into a cylindrical film by heat-sealing together.

A polyolefin raw material having a film thickness of 30 to 300 μm is cut into a predetermined length to obtain cylindrical films 31 and 41, and one end in the opening direction is closed by heat sealing to form heat sealing portions 33 and 43. Thus, the bag-shaped inner bags 3 and 4 are formed. These inner bags 3 and 4 can be appropriately subjected to gusset processing (not shown) for further providing a gusset portion as necessary.

  In the present embodiment, the two inner bags 3 and 4 thus obtained are opened in the opening 32 (or 42) of one inner bag 3 (or 4) and the other inner bag 4 (or 3) is opened. 42 (or 32) are accommodated in a nested manner with the same orientation, and are stacked so as to be at least double inside and outside. Thus, the inner bag laminate 2 in the present invention is obtained. At this time, it does not matter whether the inner bags 3 and 4 are the same or different (the raw material composition may be the same or different). Moreover, the film thickness of each inner bag may be substantially the same or different. In addition, in this specification, not only the laminated body of the inner bag which obstruct | occluded the opening direction end part of the cylindrical film but the laminated body of the cylindrical film which does not obstruct | occlude one end part is also referred to as "inner bag laminated body. ". The latter is included in the “inner bag laminate” in order to accommodate the inner bag of a flexible container having a discharge part at the bottom.

  Further, as another method for obtaining the inner bag laminate 2 in the present invention, when it satisfies the desired condition in terms of strength, two cylindrical films 31 and 41 are first overlapped on the inside and outside. In the above, one end portions of the two cylindrical films 31 and 41 may be collectively closed and formed into a bag shape by using various conventionally known methods such as heat sealing, welding or adhesion. When the flexible container 1 of the present invention is repeatedly used according to the type of the filling, a lower discharge portion is provided at the bottom of the flexible container, and the inner bag laminate 2 is also formed in accordance with the opening of the lower discharge portion. It is also possible to adopt a configuration in which the lower end portion is not closed so that the lower end side can be opened.

The flexible container 1 of this invention is not limited to the structure of the inner bag laminated body 2 which overlaps the two inner bags 3 and 4 as shown in this embodiment, The content of the contents with which the flexible container 1 is filled is included. Considering the appearance, size, filling load, etc., it is possible to change to a configuration of an inner bag laminate in which three or more inner bags are stacked in three or more layers inside and outside. In this case as well, the individual inner bags or cylindrical films may be the same or different, and the thickness of each film may be substantially the same or different from each other.

Thus, it is preferable to set the total thickness of the inner bag laminated body 2 of the present invention constituted by overlapping the inner bags 3 and 4 at least twice inside and outside in the range of 100 to 1000 μm. If the total thickness is less than 100 μm, the physical strength such as puncture resistance is low and the inner bag laminate 2 may be broken, and if it exceeds 1000 μm, the physical strength such as puncture resistance is increased. However, since the flexibility of the inner bag laminate 2 as a whole is deteriorated, the handleability and transportability are remarkably lowered.

Moreover, in this embodiment, although the cylindrical film which uses polyolefin as a main raw material was used for the inner bag laminated body, the thickness which uses polyamide as the main raw material is 30-300 micrometers in the said inner bag laminated body. A cylindrical laminate film, or a cylindrical laminate film obtained by laminating the film and a film mainly composed of the polyolefin, and having a thickness in the range of 30 to 300 μm is at least 1 in the inner bag laminate. Layers can be included.

Here, examples of the polyamide include nylons such as nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 6T, nylon 6I, nylon 9T, nylon M5T, nylon 612, and aramids. These may be used alone or in combination of two or more. As with polyolefins, films made from this polyamide as the main raw material can be added with additives such as weathering agents, antistatic agents, and antioxidants as needed for the purpose of film modification. It can be added within a range that does not affect.

The film mainly composed of the polyamide is
For example, it can be formed into a film using a conventionally known method such as stretching. In the case of the laminated film, a raw material mainly made of polyamide and a raw material mainly made of polyolefin can be formed by using a conventionally known method such as coextrusion molding, extrusion lamination molding, dry lamination molding, inflation molding or the like. . As described above, the film thus formed can be formed into a tubular film by joining both ends in the length direction or the width direction by an appropriate method.

Also when including the film etc. which use a polyamide as a main raw material in an inner bag laminated body, it is preferable to set the total thickness of the said inner bag laminated body in the range of 100-1000 micrometers similarly to the above.

Since the inner bag laminated body 2 of the present invention can be filled with various indeterminate shapes provided with the protrusions and the like in the flexible container of the present invention, its piercing quality is very important. It is preferable that the puncture strength based on JIS Z1707 about the inner bag laminated body 2 is 10N or more. This is because if the puncture strength is less than this value, the inner bag may be broken depending on the type of contents.

(2) Outer bag 5
The outer bag 5 includes a cylindrical body portion 51 and an upper charging portion 52 that is provided at an upper portion thereof and includes an opening portion 53 that opens upward. The upper input part 52 and the cylindrical trunk | drum 51 are sewn on the former lower end edge and the latter upper end edge by sewing. The upper charging part 52 and the cylindrical body part 51 may be the same or different. From the peripheral wall of the upper input part 52, the input part tied string 56 for binding this is pulled out to the outside. The upper charging part 52 and the cylindrical body part 51 can be joined also by using other conventionally known methods such as welding and adhesion.

The outer shape of the outer bag 5 is not particularly limited, and the same outer shape as that of a conventionally known flexible container can be adopted. In the present embodiment, the outer bag 5 has a configuration in which the bottom portion 54 of the cylindrical body 51 has no discharge portion, as with some cross containers, but is not limited thereto, and the flexible container of the present invention is When this is repeatedly used a plurality of times, or a lower discharge portion may be provided according to the type of the filling. Furthermore, when the content is high density and the filling load of the flexible container is large, a reinforcing material may be sewn in the circumferential direction of the cylindrical body 51 if necessary.

  Moreover, it does not restrict | limit especially about the raw material of the outer bag 5, Various materials currently used for the conventionally well-known cross container etc. can be used. For example, a yarn fabric obtained by weaving a flat yarn made of a polyolefin resin such as polyethylene or polypropylene as warp yarns 58 and weft yarns 57 with a loom can be suitably used (see FIG. 3). This yarn dough can be laminated with synthetic resin such as polyolefin (PE, PP, etc.) or rubber on one or both sides of the front and back as required.

In the outer bag 5, two suspension belts 6 and 7 extend along the side wall from the bottom 54 of the cylindrical body 51, and two loops facing each other are formed above the cylindrical body 41. Has been.
The suspension belts 6, 7 are sewn and fixed to the side wall of the tubular body 41 by applying the reinforcing cloths 8, 8 from above, near the upper end of the tubular body 41. The suspension belts 6 and 7 are used, for example, for inserting a claw of a forklift (not shown) into these two loops and lifting and moving the flexible container 1 of the present embodiment.

Next, the present invention will be described in more detail with reference to preferred embodiments of the flexible container of the present invention. In the following examples, a cylindrical film made of polyethylene as a raw material is used for the inner bag and the inner bag laminate, and a yarn fabric woven from polypropylene is used for the outer bag. In addition, this invention is not limited to a following example.

[raw materials]
(1) Polyethylene (manufactured by ExxonMobil Chemical Co., model number: Enable 20-05HE, MFR 0.5, density 0.920)
(2) Polypropylene (SABIC Innovative Plastics, model number: PP500P)
(3) Running raw fabric 1 (container (running type), nominal thickness 700 μm, manufactured by Hiraoka Orize Co., Ltd.)
(4) Running fabric 2 (container (running type), nominal thickness of 500 μm, manufactured by Hiraoka Orizome Co., Ltd.)

[Production of inner bag laminate]
Using the polyethylene as a raw material, inflation molding was performed at a blow ratio of 2.0 to prepare a cylindrical film having a film thickness of 250 μm. This cylindrical film was cut into a predetermined length, and heat sealing treatment was performed on one end to form a plurality of inner bags. Two of the inner bags were used, and these were stacked so as to be doubled inside and outside to produce an inner bag laminate. The sealing machine used was a system sealer (model number: SKS-C-15SP, manufactured by Sankyo System (Yes)), and the sealing conditions were a temperature of 155 ° C. and a speed of 0.8.

[Production of comparative film]
The polyethylene raw material was blown at a blow ratio of 2.0 to obtain a cylindrical film having a film thickness of 500 μm.

[Production of outer bag]
A flat yarn made of polypropylene was produced, and the yarn was woven with a loom using warp and weft to obtain a yarn fabric. Using this yarn fabric, a cylindrical body portion and an upper input portion were formed, and these were sewn by sewing to produce a cylindrical outer bag. This outer bag corresponds to a normal cross container.

[Example 1 (Production of flexible container)]
The said inner bag laminated body was inserted from the opening of the upper input part of the said outer bag, and the flexible container of this invention was prepared. The size is a folding diameter of 400 mm and a length of 720 mm.

[Comparative Example 1]
In the same manner as in the flexible container manufacturing method of Example 1, the inner bag made of one cylindrical film having a film thickness of 250 μm was inserted into the outer bag, and a comparative example having a folding diameter of 400 mm and a length of 720 mm was used. 1 flexible container was obtained.

[Comparative Examples 2 and 3 (production of running container)]
A plurality of running fabrics 1 and 2 cut into a predetermined size are each folded in two, and both ends in the direction of the fold are heat-sealed substantially perpendicular to each other and substantially parallel to each other. A running container having a length of 720 mm was produced.

[Evaluation method]
The inner bag, the inner bag laminate, the comparative film, the flexible container of Example 1, and Comparative Examples 1 to 3 were evaluated for puncture resistance and durability against dropping as follows.
1. 1. Sting resistance 1-1. Puncture test In accordance with JIS Z1707, a needle with a diameter of 1 mm is punctured at a speed of 10 mm / min toward each surface of the inner bag laminate and the comparative film, and the force (test force) at each break is measured. did. For reference, the same measurement was performed on the inner bag film produced as described above. The results are shown in Table 1. In Table 1, the measurement results of the puncture strength of the inner bag laminate and the comparative film are converted into the strength per 1 mm thickness of the tested films so that the puncture strengths of the two can be easily compared. .
Moreover, the same piercing | penetration test was done also about each of the inner bag laminated body and the running raw fabrics 1 and 2 of Comparative Examples 2 and 3. The results are shown in Table 2.

1-2. Penetration test ASTM
In accordance with D4833, a penetration bar having a diameter of 8 mm was pierced at a speed of 50 mm / min toward each surface of the inner bag laminate and the running raw fabrics of Comparative Examples 2 and 3, and the force at break was measured. The results are shown in Table 3.

2. Durability to fall 10 kg of a mixture of crushed stone and sand mixed at a ratio of 50:50 is filled into the flexible container obtained in Example 1, the flexible container of Comparative Example 1, and the running containers of Comparative Examples 2 and 3, respectively. After dropping 20 times from a height of 1.2 m, water was poured into the inner bag, and the number of holes (water leakage) was determined. This measurement was repeated for each of five containers, and the average value of the number of holes was obtained. The results are shown in Table 4.

3. Since the flexible containers filled with the compression test are often stacked at the time of storage, the compression test was performed in the following manner assuming damage to the inner bag laminate from the contents due to the stacking. Each of the flexible containers of Example 1 and Comparative Examples 1 to 3 was filled with 1.5 kg of a mixture of a wood chip and a protruding branch or the like (for example, disposable chopsticks, etc.) as a test specimen. The contents of each test specimen are compressed at a speed of 200 mm / min until the test force reaches 40 kN, and the scratches received by the contents of each test specimen are visually confirmed. I counted the places. This measurement was repeated for each of five containers, and the average value of the number of scratched points was obtained. The results are shown in Table 4.

  From the puncture test results in Table 1, the inner bag laminate having a total film thickness of 500 μm obtained by overlapping the inner bags so as to be doubled shows slightly higher piercing strength than a substantially equivalent comparative film. It was found that the two-layered inner bag laminate was slightly superior in stab resistance than one comparative film having a substantially equivalent thickness. For reference, in the case of one film of the inner bag, as a matter of course, the results showed that the puncture strength was about half that of the inner bag laminate and the comparative film.

From the piercing test results in Table 2, the inner bag laminate having a total film thickness of 500 μm shows a higher piercing strength than the running raw material having the same thickness. It is clear that the piercing resistance is superior to the running raw fabric.
In addition, the inner bag laminate shows a piercing strength lower than that of the 700 μm thick running raw material, which is higher than the running raw fabric when compared with a 1 mm equivalent value of both piercing strengths. The value is shown. Also from this result, it was shown that the inner bag laminate exhibited better puncture resistance than the running raw material per unit thickness.

From the test results in Table 3, it was found that the flexible container of Example 1 showed higher penetration strength than the flexible container of Comparative Example 1 and the running container of Comparative Example 3. Therefore, it is clear that the flexible container of Example 1 is more excellent in puncture resistance due to penetration strength than the containers of Comparative Example 1 and Comparative Example 3.
Moreover, although the flexible container of Example 1 has a smaller penetration strength than the running container of Comparative Example 2, the difference between the measured values is small, so that the former is more resistant to puncture due to the penetration strength than the latter. It is inferred that they are almost comparable.

From the test results of Table 4, the flexible container of Example 1 showed a smaller value for the average number of perforations in the drop test than the flexible container of Comparative Example 1 and the running container of Comparative Example 3. Therefore, it became clear that the flexible container of Example 1 is more excellent in durability against dropping than the containers of Comparative Examples 1 and 3.
In addition, the flexible container of Example 1 has a larger number of average perforations than the running container of Comparative Example 2, but since the difference in this measured value is small, the former is more resistant to repeated drops than the latter. It is inferred that they are almost comparable.
Furthermore, from the compression test results, the number of damaged parts of the flexible container of Example 1 is about half of that of the flexible container of Comparative Example 1, and the effect of overlapping the inner bags in two or more is as follows. It is obvious.

  As described above, the flexible container of the present invention has a configuration in which a plurality of inner bags are stacked so as to be at least double inside and outside to form an inner bag laminated body, so one inner bag is used. Needless to say, the puncture strength conforms to JIS Z1707, for example, in comparison with the case of using one inner bag having a thickness corresponding to the total film thickness of the inner bag laminate, as well as improving physical strength. It is advantageous in terms of physical strength such as penetration strength according to ASTM D 4833 and difficulty in perforating due to repeated dropping (durability).

  In addition, the flexible container of the present invention has a configuration in which at least two inner bags made of polyolefin, which is similarly inexpensive, are inserted into an outer bag corresponding to an inexpensive ordinary cross container, so that a conventionally known running container is used. It can be manufactured at a lower cost than a container.

  The flexible container of the present invention is effective for transporting and storing various amorphous materials such as earth and sand, sludge, rubble, vegetation and the like in addition to known powders and liquids. Therefore, the flexible container of the present invention is also used for storing or transporting decontaminated materials including earth and sand, sludge, rubble, vegetation, etc. containing radioactive materials, which have been removed by decontamination from areas contaminated with radioactive materials. It can be used suitably.

DESCRIPTION OF SYMBOLS 1 Flexible container 2 Inner bag laminated body 3, 4 Inner bag 31, 41 (Cylindrical) film 32, 42 Opening 33, 43 Heat seal part 5 Outer bag 51 Cylindrical trunk | drum 52 Top input part 53 Opening 54 Bottom part 56 Input Tie string 57 Weft 58 Warp 6,6 Suspension belt 8 Suture

Claims (11)

A flexible container comprising an inner bag laminate formed by laminating a cylindrical film having a thickness of 30 to 300 μm made of polyolefin as a main raw material at least twice inside and outside, and an outer bag. The flexible container according to claim 1, wherein the polyolefin is polyethylene or polypropylene. The flexible container according to claim 2, wherein the polyethylene is a linear low-density polyethylene having a side chain having 4 to 8 carbon atoms. The flexible container according to any one of claims 1 to 3, wherein a blending ratio of the polyolefin in each film is 20 to 100% by weight with respect to the entire film. The thermoplastic polyolefin according to any one of claims 1 to 4, wherein thermoplastic polyolefin is contained in at least one of the double-plyed cylindrical films with respect to the entire film. Flexible container. The inner bag laminate is a cylindrical film having a thickness of 30 to 300 μm mainly made of polyamide, or a cylindrical laminate film obtained by laminating the film and a film mainly containing the polyolefin. The flexible container according to any one of claims 1 to 5, comprising at least one layer having a thickness in the range of 30 to 300 µm in the inner bag laminate. The total thickness of the said inner bag laminated body is 100-1000 micrometers, The flexible container of any one of Claims 1-6. The flexible container according to any one of claims 1 to 7, wherein the outer bag is formed of a fabric woven using a flat yarn having a thickness of 30 to 140 µm made of polyolefin as a main raw material for warp and weft. . The flexible container according to any one of claims 1 to 8, wherein the inner bag laminated body has a puncture strength according to JIS Z1707 of 10 N or more. The flexible container according to any one of claims 1 to 9, wherein the flexible container is used for storing or transporting various irregular shapes such as earth and sand, sludge, rubble and vegetation. The method according to any one of claims 1 to 9, wherein the decontamination product is used for storing or transporting decontaminated matter including earth and sand, sludge, rubble, vegetation and the like containing radioactive material, which has been removed by decontamination. Flexible container.

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