Seamless flexible intermediate bulk container bag and method for manufacturing the same

Abstract

We disclose a seamless flexible intermediate bulk container (FIBC) bag that facilitates recycling, eliminates the problem of residual material entering the raw material inventory, and enables mass production without requiring skilled workers. [Solution] The product is manufactured by a method that includes the steps of: making the main body by cutting a tunnel-shaped fabric made of PP fabric to a predetermined length; making the lower plate by covering it with a reinforcing plate and fusing it with ultrasonic waves to form a rope tunnel and fusing a cylindrical discharge port to the outside of the rope tunnel; making the upper plate by drilling a circular injection port in the center of the PP fabric and fusing a cylindrical injection port around it; making a belt by folding it with ultrasonic waves; making a lifting ring by ultrasonically fusing both ends of the belt to the upper part of the main body; making a lifting ring by ultrasonically fusing the lower plate to the lower part of the main body; and making the final flexible container bag by ultrasonically fusing the upper plate to the upper part of the main body.

Description

Technical Field

[0001] The present invention relates to a seamless flexible container bag and a method for manufacturing the same. Specifically, by unifying the members forming the flexible container bag into a polypropylene (PP) material, recycling after use of the flexible container bag is facilitated, and sufficient strength is maintained even when joining between members is performed by ultrasonic welding instead of sewing work, thereby solving the problem of raw material inflow of residues generated in the sewing production method, enabling mass production without the need for skilled sewing workers, and obtaining price competitiveness.

Background Art

[0002] Generally, a flexible container bag is also called a container bag, FIBC (Flexible Intermediate Bulk Container), big bag, bulk bag, etc., and is for transporting and storing agricultural products, chemical raw materials, etc. in a bulk state, and is formed using a flexible synthetic fiber fabric so that the storage and removal of the contents can be conveniently performed.

[0003] Such a flexible container bag stores contents such as chemicals, minerals, grains, synthetic resin powder materials, cement, etc. in an amount of about 500 Kg to 2,000 Kg, and may be transported by a crane, hoist, forklift, etc. and stored in a warehouse, or may be loaded on a truck and transported. The contents include powders such as pellets, granules, and powders.

[0004] On the other hand, the aforementioned flexible container bags are made of polypropylene fabric on the sides, top, and bottom, with lifting belts made of nylon, and the sides and top / bottom are sewn together with nylon sewing thread. Inlet and outlet ports made of PP or PE material are sewn onto the top and bottom. As a result, residue remains inside the flexible container bag during the sewing process, is introduced into the flexible container bag and mixed in with the raw materials when raw materials are injected, and is discharged together with the raw materials when discharged and introduced into the product production line. Therefore, there was a risk of product defects or product flaws due to foreign matter contamination.

[0005] Furthermore, conventional flexible intermediate bulk containers (FIBCs) require skilled seamstresses, and their three-dimensional, enclosed structure makes them difficult to sew. Even skilled seamstresses take a long time to sew a single FIBC, resulting in low productivity and low price competitiveness. Even when skilled seamstresses work on them, the stitching is not always perfect; even a slight deviation from the reference line results in a defect, and in severe cases, the bag may tear.

[0006] According to the applicant's search, prior art relating to the present invention includes the disclosure of Patent Documents 1 to 4, among others.

[0007] Patent Document 1 (August 16, 2024) is a prior registered patent of the present applicant, which describes a method for forming the injection and discharge ports of the outer shell by heat fusion without sewing, thereby eliminating the risk of foreign matter such as residue being mixed into the raw materials. However, since the parts other than the injection and discharge ports are still joined by sewing, the inconvenience of having to separate or dismantle the flexible container bag for recycling still remains.

[0008] In addition, technologies for manufacturing flexible intermediate bulk containers (FIBCs) to improve production efficiency and recyclability, as well as technologies for manufacturing FIBCs using a combination of heat sealing and sewing, have been disclosed in Patent Documents 2 to 4, etc. However, these have not completely solved the aforementioned problems, and the heat sealing method for joining components has the drawback that certain parts, such as the joint between the side and bottom surfaces, cannot provide sufficient strength required for FIBCs. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Korean Registered Patent Publication No. 10-2697463 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The present invention was made to solve the aforementioned problems. The present invention aims to manufacture flexible container bags (FIBCs) used for transporting or storing large quantities of various food products and chemical raw materials formed in powder form from a single material, thereby facilitating recycling by eliminating the need for separate separation or dismantling processes after use. Furthermore, it aims to ensure uniform quality by joining all joints and connections using ultrasonic fusion, without requiring a sewing process which is difficult and demands considerable skill, thereby preventing the contamination of raw materials, including residues, with various foreign substances when they are filled into the container bags for storage and transport. [Means for solving the problem]

[0011] To achieve the above objective, the present invention provides a method for creating a main body with a circular or square cross-section by cutting a tunnel-shaped fabric made of polypropylene fabric (hereinafter referred to as "PP fabric") to a predetermined length; cutting an X-shaped discharge port in the center of the circular or square PP fabric, folding four triangular plates cut in the X shape, covering them with a reinforcing plate and fusing them together with ultrasonic waves to form a rope tunnel, and fusing a cylindrical discharge port to the outside of the rope tunnel to create a bottom plate; and cutting an X-shaped or circular inlet in the center of the circular or square PP fabric. The present invention provides a method for manufacturing a seamless flexible container bag, comprising the steps of: forming a top plate and fusing a cylindrical inlet around the inlet; folding a PP fabric of a predetermined width and length on both sides and folding it by ultrasonic welding to create a belt; ultrasonically welding both ends of the belt to the upper side of the main body to form a lifting ring; attaching the bottom plate to the lower part of the main body by ultrasonic welding; and finally completing the flexible container bag by ultrasonic welding the top plate to the upper part of the main body.

[0012] In a preferred embodiment, the lower end of the main body is folded inward at a right angle to form a circular or square perimeter, and the lower plate is placed under the circular or square perimeter and ultrasonically fused; or, without folding the lower end of the main body, the outer edge of the lower plate is folded upward at a right angle to form a perimeter, and the perimeter is placed inside the lower end of the main body and ultrasonically fused, thereby ensuring sufficient durability against tensile forces due to the load of the contents.

[0013] Furthermore, the present invention provides a seamless flexible container bag manufactured by the manufacturing method described above. [Effects of the Invention]

[0014] According to the embodiments of the present invention described above, in the step of manufacturing the flexible container bag, when joining members, all are performed by ultrasonic welding without going through the sewing process. Therefore, it is possible to prevent the problem that foreign substances such as thread scraps (residues) remain inside the bag and mix into the contents. Since the upper and lower plates and the lifting ring are joined to the main body by ultrasonic welding, not only is no skilled sewing personnel required, but the quality uniformity can be achieved, mass production becomes easy, price competitiveness is obtained, and since it is formed of a single material, there are advantages such as easy recycling without separately separating or disassembling after use of the flexible container bag.

Brief Description of the Drawings

[0015] [Figure 1] It is a flowchart for explaining the manufacturing process of the flexible container bag according to the present invention. [Figure 2] It is an explanatory view of the step of manufacturing the main body shown in FIG. 1. [Figure 3] It is an explanatory view of the step of manufacturing the lower plate. [Figure 4] It is an explanatory view of the step of manufacturing the upper plate. [Figure 5] It is an explanatory view of the step of manufacturing the lifting ring. [Figure 6] It is a diagram showing the joined state of the lifting ring and the lower plate. [Figure 7] It is a diagram showing the joined state of the upper plate. [Figure 8] It is a photograph of the actual flexible container bag according to the present invention. [Figure 9] It is an enlarged photograph of the welded part of the lifting ring shown in FIG. 8. [Figure 10] It is a photograph of the actual welded state of the main body and the lower plate in the flexible container bag shown in FIG. 8. [Figure 11] It is a perspective view of the lower plate showing another embodiment of the present invention. [Figure 12] It is a diagram showing the welded state of the lower plate shown in FIG. 11.

Modes for Carrying Out the Invention

[0016] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, which do not limit the present invention.

[0017] FIG. 1 shows the overall manufacturing process of the seamless flexible container bag according to the present invention, and FIGS. 2 to 8 show the manufacturing processes of the respective parts forming the flexible container bag according to the first embodiment of the present invention, the overall joined state, and a photograph of the completed product.

[0018] In the drawings, reference symbol W indicates an ultrasonic fusion part, and in the following detailed description, it is also referred to as "fusion W" or simply "fusion" without using the reference symbol.

[0019] As can be seen from the drawings and the photograph of the product, the manufacturing method of the seamless flexible container bag according to this embodiment includes: Step S100 of cutting a tunnel-shaped fabric made of PP fabric to a predetermined length to form a square cross-section, and folding the peripheral edge 12 at the lower end inward at a right angle with a predetermined width to produce the main body 10; Step S200 of cutting an outlet 21 in an X shape at the center of the square PP fabric, folding the four triangular plates 22 cut in an X shape, covering with a reinforcing plate 24, and fusing with ultrasonic waves to form a rope tunnel 26, and fusing a cylindrical outlet 28 to the outside of the rope tunnel 26 to produce a lower plate 20; Step S300 of punching a circular inlet 31 at the center of the square PP fabric and fusing a cylindrical inlet 32 around the circular inlet 31 to produce an upper plate 30; Step S400 of folding both left and right sides of a PP fabric with a predetermined width and length and folding by ultrasonic fusion to form a belt 40, winding a reinforcing band 42 around the outside of the belt 40 and fusing to produce the belt 40; Step S500 of ultrasonically fusing both ends of the belt 40 to the corner sides of the upper four surfaces of the main body 10 to form a lifting ring 40'; Step S600 of attaching the lower plate 20 to the peripheral edge of the lower part of the main body 10 by ultrasonic fusion; and Step S700 of attaching the upper plate 30 to the upper part of the main body 10 by ultrasonic fusion to finally complete the flexible container bag 1.

[0020] In this embodiment, steps S100, S200, S300, and S400 may be performed sequentially, or they may be performed simultaneously. After each of the steps S100, S200, S300, and S400 is performed independently, the lifting ring forming step S500 and the lower plate attachment step S600 are performed first, and finally the upper plate attachment step S700 is performed to complete the flexible container bag.

[0021] On the other hand, the order of the lifting ring forming step S500 and the lower plate attachment step S600 may be changed.

[0022] In this embodiment, step S100 for manufacturing the main body 10 involves cutting a 180cm wide (overlapping) tunnel (tube) shaped fabric made of PP (polypropylene) fabric, which is used to manufacture general flexible container bags, to a predetermined length (127cm). The PP fabric has a moisture-proof and waterproof coating on one side (inner surface). The fabric is folded so that it has a rectangular cross-section when viewed from above as shown in Figure 2(a), and the lower edge 12 is folded inward at a right angle by a predetermined width (7cm) as shown in the bottom view shown in Figure 2(b) and the bottom perspective view shown in Figure 2(c), so that the edge 12 overlaps at the corners to manufacture the main body 10.

[0023] To form the periphery 12, notches T of about 7 cm can be formed at the four corners of the lower end of the main body 10, as shown in (a) of the figure, or it goes without saying that the parts can be folded so that they overlap at the corners without forming separate notches.

[0024] On the other hand, it is preferable to temporarily attach the overlapping portion at the corner by ultrasonic fusion (not shown) so that the state in which the periphery 12 overlaps at the corner is maintained, and the state in which the periphery 12 is folded at a right angle is maintained.

[0025] In this embodiment, the lower end of the main body 10 is folded inward at a right angle to form a rectangular perimeter 12, and as shown in Figure 6, the lower plate 20 is placed under the rectangular perimeter 12 and ultrasonic fusion W is performed. However, in the second embodiment shown in Figures 10 and 11, the lower end of the main body 10 is not folded, and the outer edge of the lower plate 20 is folded upward at a right angle to form a perimeter 23, and the perimeter 23 is placed inside the lower end of the main body 10 and ultrasonic fusion W is performed on each other.

[0026] In the second embodiment shown in Figures 10 and 11, it is preferable to temporarily attach the periphery 23, which overlaps at a right angle at the corner, by ultrasonic fusion so that the state in which the outer edge of the lower plate 20 is folded upward at a right angle to form the periphery 23 is maintained.

[0027] The change in the formation position of the periphery 12 or periphery 23, as described above, that is, whether to form the folded periphery at the lower end of the main body 10 or on the outer edge of the lower plate 20, can be selectively done according to the convenience of the manufacturer, and even if the position of the periphery 12 or 23 is changed, the joint strength between the main body 10 and the lower plate 20 by ultrasonic fusion W remains the same. This will be explained below.

[0028] In the present invention, as described above, the main body 10 and the lower plate 20 that form the flexible container bag are not in contact with each other, but rather the ultrasonic fusion W is performed with a predetermined width overlapping between them, i.e., the width of the periphery 12 or periphery 23. Therefore, when the flexible container bag is stored and lifted with contents inside, there is no risk of the fused portion tearing due to the pressure it receives, and a stable bond can be maintained. This is because, when subjected to the pressure of the contents, if the main body 10 and the lower plate 20 are in contact and ultrasonic fusion is performed, the contacted and fused portion is vulnerable to tearing and opening due to tensile force. However, when the main body 10 and the lower plate 20 are overlapped and fused W is performed, even if tensile force is applied to the fused joint between the main body 10 and the lower plate 20 of the flexible container bag that form the side surface of the flexible container bag, the fusion is performed with a predetermined width overlapping between them. Therefore, the direction in which the tensile force is applied and the direction in which the ultrasonic fusion is performed are the same, and the ultrasonic fused portion exhibits sufficient resistance to such tensile force.

[0029] In the following explanation, the materials used for the bottom plate 20, top plate 30, discharge port 28, and inlet port 32 are all coated on the inside with moisture-proof and waterproof coatings, so redundant explanations regarding this will be omitted.

[0030] In this embodiment, step S200 for manufacturing the lower plate 20 involves cutting an X-shaped outlet 21 in the center of a rectangular PP fabric (89 cm in both length and width), as shown in Figure 3(a); folding four X-shaped triangular plates 22 downwards and placing them on top of the lower plate 20, as shown in Figure 3(b); placing a rectangular reinforcing plate 24 over the outside of the folded portion and fusing it with ultrasonic waves to form a rope tunnel 26, as shown in Figure 3(c); and finally, as shown in Figure 3(d), ultrasonically fusing a separate cylindrical outlet 28 to the outside of the rope tunnel 26 to complete the lower plate 20.

[0031] The reinforcing plate 24 in the diagram is subjected to ultrasonic fusion W throughout.

[0032] Figure 3 shows the specified specifications (dimensions) of the reinforcing plate 24 of the outlet 21 and the cylindrical outlet 28, but the present invention is not limited to these, and it goes without saying that it can be manufactured to various specifications as needed.

[0033] A standard rope (not shown) used in flexible intermediate bulk containers (FIBCs) is fitted into the rope tunnel 26, and a fastener made of resin tubing is provided on the rope. A string is also provided on the cylindrical discharge port 28 to close it. However, since such ropes, strings, and fasteners are well known in the art to which the present invention belongs, their specific illustrations and descriptions are omitted. Furthermore, since the ropes, strings, and fasteners can be easily removed when recycling the FIBCs, other materials may be used instead of PP.

[0034] In this embodiment, step S300 for manufacturing the top plate 30 involves drilling a circular injection port 31 with a diameter of 40 cm in the center of a rectangular PP fabric (100 cm in both length and width), as shown in Figure 4(a), and then fusing a separately manufactured cylindrical injection port 32 around the circular injection port 31 to complete the top plate 30, as shown in Figure 4(b).

[0035] In this embodiment, a circular injection port 31 is drilled in the upper plate 30, but the present invention is not limited thereto, and it goes without saying that the injection port may be formed in an X shape, similar to the lower plate.

[0036] In this embodiment, step S400 for manufacturing the belt 40 is as follows: As shown in Figure 5(a), a PP fabric of a predetermined width (25 cm) and length (160 cm) is folded on both sides and ultrasonically fused to form the belt 40. As shown sequentially in Figures 5(b), (c), and (d), a reinforcing strip 42 made of double-sided coated PP fabric or PE (polyethylene) fabric, having a length of 30 cm and a width of 20 cm, is wrapped around the outside of the middle part of the belt 40, folded to a width of 8 cm, and fused to complete the belt 40.

[0037] The following steps S500, S600, and S700 are performed to attach the prepared lower plate 20, upper plate 30, and belt 40 to the main body 10. First, as shown in Figure 6, step S500 is performed to form a lifting ring 40' by ultrasonic fusion W to the corners of the four upper surfaces of the main body 10. Next, step S600 is performed to attach the lower plate 20 to the lower rectangular periphery 12 of the main body 10 by ultrasonic fusion W.

[0038] In this embodiment, as can be seen from the enlarged view in Figure 6, the lifting ring 40' is fused using multiple fusion pins spaced apart vertically and horizontally, and ultrasonic fusion W is performed over a wide area across the entire upper and lower ends of the lifting ring 40'. Therefore, even if the lifting ring 40' is subjected to tensile force (load) from above and below when lifting the flexible container bag, there is no risk of the lifting ring 40' falling off the main body 10.

[0039] Furthermore, in step S600, the lower edge 12 of the main body 10 and the outer casing of the lower plate 20 are joined by ultrasonic fusion W while in an up-and-down position. However, the ultrasonic fusion W between the main body 10 and the lower plate 20 is performed continuously using multiple fusion pins to form a band of a predetermined width (approximately 3-4 cm), similar to the fusion of the lifting ring 40' described above. Therefore, there is no risk of the fused portion breaking even when subjected to tensile force due to the load of the contents.

[0040] Step S700, in which the top plate 30 is attached, is the final step. As shown in the enlarged view of Figure 7, the outer edge of the top plate 30 is brought into contact with the outer edge of the upper end of the main body 10 and attached by ultrasonic fusion. Here, as with the fusion of the lifting ring 40' described above, fusion is performed using multiple fusion pins to create a predetermined width (approximately 3-4 cm). In the step of attaching the top plate 30, it is not structurally possible to perform overlapping fusion, so fusion is performed by bringing them into contact. However, even when the top plate 30 is stored and lifted with contents filled inside the flexible container bag, not much tensile force is applied to the top plate 30, so there is no structural problem. The reason for determining the manufacturing order described above is that sufficient resistance to the tensile force generated by the load of the contents is required for the fusion between the main body and the bottom plate, which must be performed before the fusion between the main body and the top plate, and the joining of those parts must be overlapped.

[0041] Figure 8 shows a photograph of an actual flexible container bag according to this embodiment, Figure 9 shows a photograph of an actual flexible container bag with the lifting ring 40' ultrasonically fused to the upper part of the main body 10, Figure 10 shows the lower plate 20 superimposed on the periphery of the main body 20 and ultrasonically fused, and Figure 11 shows the upper plate 30 in contact with the upper end of the main body 20 and ultrasonically fused.

[0042] In this embodiment, the flexible container bag is constructed such that the main body, top plate, bottom plate, inlet, and outlet are all made of a single material, and the joining is done by ultrasonic fusion rather than sewing. Therefore, it can be mass-produced efficiently using an ultrasonic fusion device even without skilled sewing workers, there is no risk of residue flowing in, and there is no need to separate or dismantle the flexible container bag into its various parts during recycling, thus improving recyclability and offering other useful effects.

[0043] Figure 12 is a perspective view of the lower plate forming a flexible container bag according to a second embodiment of the present invention, and Figure 13 shows the lower plate shown in Figure 12 fused to the lower end of the main body.

[0044] In this embodiment, as shown in Figure 12, the outer edge of the rectangular lower plate 20, which is made of PP fabric measuring 100 cm in length and width, is folded upwards at a right angle by a width of approximately 5 cm to form the periphery 23, and as shown in Figure 13, the periphery 23 of the lower plate 20 is overlapped with the inside or outside of the lower end of the main body 10 and formed by ultrasonic fusion W. In this method as well, the tensile strength due to the fusion between the main body 10 and the lower plate 20 is the same as the tensile strength of the first embodiment described above.

[0045] Although this embodiment illustrates and describes a flexible container bag with a rectangular cross-section, the present invention is not limited to this and can be directly applied to flexible container bags with a circular cross-section. [Industrial applicability]

[0046] As mentioned above, when the manufacturing method for seamless flexible intermediate bulk containers (FIBCs) according to the present invention is applied, the joining of the main body and the upper and lower plate members, as well as the joining of the upper plate to the inlet and the lower plate to the outlet, is all carried out by ultrasonic fusion without going through a sewing process. This prevents the problem of foreign matter such as thread scraps (residue) remaining inside the bag and mixing with the contents. Since the upper and lower plates and the lifting ring are joined to the main body by ultrasonic fusion, not only is skilled sewing personnel not required, but mass production becomes easier, price competitiveness is achieved, and since the entire FIBC is formed from a single material, there is the advantage that recycling can be easily carried out without the need for separate separation or dismantling after use. [Explanation of Symbols]

[0047] 10 Main Unit 12 Periphery 20 Lower plate 21 Outlet 22 Triangular plate 23 Periphery 24 Reinforcement plate 26 Rope Tunnel 28 Cylindrical outlet 30 Top board 31 Circular Inlet 32 Cylindrical inlet 40 belts 42 Reinforcement band 40' Lifting Ring W Ultrasonic fusion (fusion part) T-shaped notch

Claims

1. Step S100 involves cutting a tunnel-shaped fabric made of polypropylene (PP) to a predetermined length to produce a main body 10 with a circular or square cross-section, Step S200 involves cutting an X-shaped outlet 21 into the center of a circular or square polypropylene (PP) fabric, folding four X-shaped triangular plates 22, covering them with a reinforcing plate 24, and fusing them together with ultrasonic waves to form a rope tunnel 26, and then fusing a cylindrical outlet 28 to the outside of the rope tunnel 26 to produce a lower plate 20. Step S300 involves forming an X-shaped or circular injection port 31 in the center of a circular or square polypropylene (PP) fabric, and fusing a cylindrical injection port 32 around the circular injection port 31 to produce an upper plate 30. Step S400 involves folding both the left and right sides of a polypropylene (PP) fabric of a predetermined width and length and folding it by ultrasonic welding to form a belt 40, Step S500 involves ultrasonically fusing both ends of the belt 40 to the corners of the four upper surfaces of the main body 10 to form a lifting ring 40', Step S600 involves attaching the lower plate 20 to the lower part of the main body 10 by ultrasonic fusion, A method for manufacturing a seamless flexible container bag, characterized by including step S700, which involves attaching the upper plate 30 to the upper part of the main body 10 by ultrasonic fusion to finally complete the flexible container bag 1.

2. Step S100 for manufacturing the main body 10 involves cutting a tunnel (tube) shaped fabric made of polypropylene to a predetermined length to form a circular or square cross-section, and folding the lower edge 12 inward at a right angle by a predetermined width so that the edges 12 overlap at the corners, and in step S600, a lower plate 20 is placed under the edge 12 and ultrasonically fused, characterized in that the method for manufacturing a seamless flexible container bag according to claim 1.

3. The method for manufacturing a seamless flexible container bag according to claim 1, characterized in that step S100 for manufacturing the main body 10 involves cutting a tunnel (tube) shaped fabric made of polypropylene to a predetermined length to form a circular or square cross-section, and forming the main body 10 without folding the lower end, and then folding the outer edge of the lower plate 20 upward at a right angle to form a periphery 23, and overlapping the periphery 23 with the inside of the lower end of the main body 10 and performing ultrasonic fusion.

4. The method for manufacturing a seamless flexible container bag according to claim 1, characterized in that in step S400, a reinforcing strip 42 made of PP fabric or PE fabric having a predetermined width and predetermined distance is wrapped around the outside of the intermediate portion of the belt 40 and fused together.

5. A seamless flexible container bag manufactured by the manufacturing method described in any one of claims 1 to 4.

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