Cylindrical water-permeable material

Abstract

To provide a cylindrical water-permeable material that can reduce the amount of monofilament used and the manufacturing costs, and has sufficient tensile strength and compressive strength, and a manufacturing method thereof.SOLUTION: A cylindrical water-permeable material 1 has a cylindrical shape as a whole and is composed of monofilament rolls 2a to 2d stacked in the radial direction. Each of the monofilament rolls 2a to 2d is formed into a cylindrical shape in a state in which a plurality of synthetic resin monofilaments 11 are randomly curved or bent in three-dimensional directions and entangled, and have a large number of continuous voids inside. In this cylindrical water-permeable material 1, a water-permeable sheet 3 is disposed between two stacked monofilament rolls 2b and 2c.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a water-permeable material that is buried underground to drain water that has seeped into the ground due to rainfall or underground spring water to the outside, or is used for drainage on slopes or slopes, and a method for manufacturing the same. [Background technology]

[0002] In drainage devices that are buried underground for the purpose of discharging seepage water and spring water from underground to the outside, permeable material with many continuous voids is placed inside the drainage device to prevent foreign matter from entering the device and to ensure space to serve as a drainage channel.

[0003] There are various types of permeable materials that can be installed in drainage devices. For example, there is a material in which multiple synthetic resin monofilaments are randomly curved or bent in three dimensions and entangled, and integrated with continuous voids inside. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-275876 A [Patent Document 2] Patent Publication No. 2022-141015 Summary of the Invention [Problem to be solved by the invention]

[0005] When manufacturing a water-permeable material by randomly curving or bending multiple monofilaments, it is not particularly difficult to mold it into a plate or sheet shape with a thickness of about 10 to 30 mm. However, when attempting to manufacture a square rod-shaped water-permeable material with width and height dimensions of about 70 to 100 mm by curving or bending multiple monofilaments to match the size of the cross section (cross section perpendicular to the longitudinal direction) of a drainage channel in a drainage device, for example, the weight of the upper layer causes the lower layer to be compressed, resulting in an unnecessarily high density on the lower layer side, and as a result, the amount of monofilament used (i.e., the amount of synthetic resin raw material used) increases, resulting in increased manufacturing costs.

[0006] The present invention seeks to solve such problems in the prior art, and aims to provide a cylindrical water-permeable material that can reduce the amount of monofilament used and the manufacturing costs, and a manufacturing method thereof. [Means for solving the problem]

[0007] The cylindrical water-permeable material of the present invention has an overall cylindrical shape and is composed of two layers (three or four or more layers) of monofilament rolls stacked radially, and each monofilament roll is characterized in that a plurality of synthetic resin monofilaments are randomly curved or bent in three dimensions and entangled, and are formed into a cylindrical shape with a large number of continuous voids inside.

[0008] In this cylindrical water-permeable material, it is preferable that a water-permeable sheet is disposed between the two laminated monofilament rolls.

[0009] The manufacturing method of the cylindrical water-permeable material according to the present invention is characterized in that at least two lines are prepared for manufacturing a flat-shaped primary molded product having continuous gaps therein by randomly curving or bending a plurality of monofilaments made of synthetic resin and having a diameter of 1 to 3 mm extruded from an extrusion molding machine in three-dimensional directions and entangling them with each other, and a roll processing device is prepared having a winding shaft connected to the drive shaft of a motor and configured to rotate in a predetermined direction by the driving force of the motor, the primary molded product manufactured by one line is supplied obliquely to the winding shaft and spirally wound around the outside of the winding shaft to form a first layer monofilament roll, and the primary molded product manufactured by the other line is supplied obliquely to the winding shaft and spirally wound around the outside of the first layer monofilament roll to form a second layer monofilament roll.

[0010] The roll processing device used in this method includes a side edge guide that contacts the side edge of the primary molded product to be supplied and guides the primary molded product in a spiral direction, and an outer guide that presses the primary molded product to be supplied from the radially outer side of the winding shaft, the side edge guide has a spirally curved shape, is disposed and fixed so as to surround the outside of the winding shaft, and is configured to contact the side edge of the primary molded product to be supplied and guide the primary molded product in the spiral direction outside the winding shaft, and the outer guide is configured to guide the primary molded product in the spiral direction outside the winding shaft. It is preferable that the winding shaft has a curved shape, is arranged and fixed so as to partially surround the winding shaft at a position spaced a certain distance from the outer peripheral surface of the winding shaft, and is configured to press the supplied primary molded product from the radially outside of the winding shaft, and that the primary molded product is supplied so that its side edge is aligned with the side edge guide and is then wound by entering the gap between the outer guide and the winding shaft or the gap between the outer guide and the inner monofilament roll.

[0011] It is also preferable to arrange a line for supplying a water-permeable sheet between any two of the multiple lines for producing primary molded products, wrap the water-permeable sheet around the outer surface of the monofilament roll formed from the primary molded products supplied from one line, and then wrap the primary molded products supplied from the other line around the outer surface of that, thereby arranging the water-permeable sheet between the two stacked monofilament rolls.

[0012] Furthermore, it is preferable to dispose a feed roller at a position where it can contact the outer peripheral surface of the monofilament roll, and to supply a driving force to the feed roller to rotate it in a predetermined direction, thereby feeding the molded product to the tip side of the winding shaft. Effect of the Invention

[0013] The cylindrical water-permeable material according to the present invention can be manufactured by a very simple method, and the amount of synthetic resin raw material used can be reduced, thereby reducing the manufacturing cost. Furthermore, the manufacturing method for the cylindrical water-permeable material according to the present invention is expected to improve the tensile strength and compressive strength of the molded monofilament.

[0014] In addition, when a water-permeable sheet is placed between two stacked monofilament rolls, it is possible to prevent foreign matter (gravel, sand, soil, etc.) from entering the center of the cylindrical water-permeable material, and it is expected that the rigidity of the cylindrical water-permeable material will be improved. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a cross-sectional view of a cylindrical water-permeable material 1 according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a partial enlarged view of one monofilament 11 constituting the cylindrical water-permeable material 1 shown in FIG. [Diagram 3] FIG. 3 is an explanatory diagram of a method for producing a cylindrical water-permeable material according to a second embodiment of the present invention, and is a perspective view of an extrusion molding machine 71, a conveyor 81, and the like. [Figure 4]FIG. 4 is a diagram showing the structure of the underside of the die 72 shown in FIG. [Diagram 5] FIG. 5 is a diagram showing an example of the shape of the monofilament 11 supplied and conveyed on the conveyor 81. As shown in FIG. [Figure 6] FIG. 6 is a side view of the extrusion molding machine 71 and the like shown in FIG. [Figure 7] FIG. 7 is a plan view of a roll processing device 61 used in the manufacturing method of a cylindrical water-permeable material according to the second embodiment of the present invention. [Figure 8] FIG. 8 is a diagram showing a vertical cross section of the winding shaft 62 taken along line XX shown in FIG. [Figure 9] FIG. 9 is an explanatory diagram of a method for producing a cylindrical water-permeable material according to the second embodiment of the present invention. [Figure 10] FIG. 10 is an explanatory diagram of a manufacturing method of a cylindrical water-permeable material according to the second embodiment of the present invention. [Figure 11] FIG. 11 is an explanatory diagram of a manufacturing method of a cylindrical water-permeable material according to the second embodiment of the present invention. [Figure 12] FIG. 12 is an explanatory diagram of a method for producing a cylindrical water-permeable material according to the second embodiment of the present invention. [Figure 13] FIG. 13 is an explanatory diagram of a manufacturing method of a cylindrical water-permeable material according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present invention can be embodied not only as a "cylindrical water-permeable material" but also as a "manufacturing method for a cylindrical water-permeable material". Hereinafter, each embodiment of the present invention will be described with reference to the accompanying drawings.

[0017] (First embodiment: cylindrical water-permeable material) Fig. 1 is a cross-sectional view of a cylindrical water-permeable material 1 according to a first embodiment of the present invention. As shown in the figure, this cylindrical water-permeable material 1 has a cylindrical shape as a whole and is composed of four layers of monofilament rolls 2a to 2d laminated in the radial direction, and a water-permeable sheet 3 disposed between them. However, the water-permeable sheet 3 may be omitted (the cylindrical water-permeable material 1 may be composed only of the four layers of monofilament rolls 2a to 2d) in consideration of the usage situation, application, etc.

[0018] Each of the monofilament rolls 2a to 2d is formed by forming a cylindrical shape of a plurality of synthetic resin monofilaments 11 (diameter 1.5 to 2.5 mm, preferably 2 mm) that are randomly curved or bent in three-dimensional directions and entangled, and have a large number of continuous voids inside. In this embodiment, the thickness of each of the monofilament rolls 2a to 2d is set to 15 mm, but can be appropriately set within a range of 10 to 30 mm. The water-permeable sheet 3 is composed of a water-permeable synthetic resin nonwoven fabric (thickness 0.2 mm).

[0019] Fig. 2 is an enlarged view of one monofilament 11 constituting the cylindrical water-permeable material 1 shown in Fig. 1. As shown in the figure, a large number of small irregularities with a height or depth of about 0.1 to 0.5 mm are formed on the surface of the monofilament 11, and the entire surface is not smooth but is configured as a rough surface.

[0020] The cylindrical water-permeable material 1 of this embodiment has a diameter of about 160 mm, but is not limited to this dimension. The length is also not particularly limited and can be any length. For example, it can be about 1 to 4 m, which is easy to handle, and can be 10 m or more if necessary.

[0021] This cylindrical water-permeable material 1 can be housed in a plastic gutter-shaped case or the like to form a drainage device. In this drainage device, the housed cylindrical water-permeable material 1 can reduce the flow resistance of water in the gutter-shaped case, and the seepage water can be quickly drained. Even if this drainage device is placed underground, it can withstand earth pressure without any problems, and a drainage path (continuous space) can be permanently secured in the gutter-shaped case. When the cylindrical water-permeable material 1 is housed in the gutter-shaped case, it is preferable to place a water-permeable mesh sheet (nonwoven fabric, etc.) on the cylindrical water-permeable material 1 to prevent the intrusion of foreign matter such as gravel, sand, and soil.

[0022] Moreover, a drainage device with a simpler structure can be constructed by covering the bottom and both the left and right sides of the cylindrical water-permeable material 1 with a waterproof sheet without using a gutter-shaped case or the like.

[0023] Although the cylindrical water-permeable material 1 of this embodiment is composed of four layers of monofilament rolls 2a to 2d and a water-permeable sheet 3 arranged between them, it is also possible to arrange one or more monofilament rolls further outside the outermost monofilament roll 2d shown in Fig. 1 to make the cylindrical water-permeable material have a structure of five or more layers. Also, the cylindrical water-permeable material can be composed of only two or three layers of monofilament rolls (or by these and a water-permeable sheet arranged between them).

[0024] (Second embodiment: manufacturing method of cylindrical water-permeable material) The cylindrical water-permeable material according to the present invention can be manufactured by the following method. First, a synthetic resin raw material is supplied to an extrusion molding machine 71 shown in FIG. 3, and extrusion molding is performed to extrude a linear synthetic resin (monofilament 11) having a diameter of 2 mm (or 1.5 to 2.5 mm) downward from a die 72. A conveyor 81 (belt conveyor or vibration conveyor) is arranged below the die 72, and the monofilament 11 extruded from the die 72 is supplied onto the conveyor 81. At the supply position of the monofilament 11 on the conveyor 81 (the base end side of the conveyor 81), a pair of parallel side guides 83 (spacing dimension: 50 mm) for defining the width dimension (50 mm) of the molded product are arranged. The spacing between these side guides 83 can be appropriately changed according to the width dimension of the molded product.

[0025] Fig. 4 is a diagram showing the structure of the underside of the die 72 shown in Fig. 3. As shown in the figure, a plurality of small holes 73 (four in total in this embodiment) with a diameter of 2 mm that open downward are formed on the underside of the die 72.

[0026] When the monofilament 11 is extruded from the die 72 and supplied onto the conveyor 81, if the conveying speed of the conveyor 81 is set to be the same as the extrusion speed of the monofilament 11 from the die 72, the monofilament 11 will be conveyed in a generally straight shape on the conveyor 81. However, if the conveying speed of the conveyor 81 is set to be slower than the extrusion speed of the monofilament 11, as shown in FIG. 5, the monofilament 11 will be conveyed in a shape that is randomly curved or bent in the longitudinal and lateral directions on the conveyor 81, and curved or bent in the vertical direction at the overlapping portions.

[0027] As shown in FIG. 6, above the tip of the conveyor 81, a press belt roller 82 is arranged which can move vertically as appropriate and apply a pressing force from above, so that the thickness dimension of the molded products passing between the conveyor 81 and the press belt roller 82 can be made uniform (for example, to 15 mm).

[0028] In this manner, a plurality of monofilaments 11 are randomly curved or bent in three dimensions (longitudinal, transverse, and vertical) and entangled, resulting in the production of a flat primary molded product 5 having numerous continuous internal voids and a transverse dimension of approximately 50 mm and a thickness of approximately 15 mm.

[0029] Furthermore, by adjusting the molding temperature (temperature of the resin immediately after extrusion) in the extrusion molding machine 71, the extrusion pressure (extrusion speed) of the resin, the height dimension from the top surface of the conveyor 81 to the bottom surface of the die 72, and the conveying speed of the conveyor 81, it is possible to change the curvature or bending state of each monofilament 11 on the conveyor 81 (the swing width in the width direction, the average curvature of the curved portion, etc.) and the degree of entanglement.

[0030] In addition, although a belt conveyor is shown as the conveyor 81 for conveying the monofilament 11 or the primary molded product 5 in Figures 3, 5, and 6, a vibrating conveyor that conveys an object by vibration can also be used.

[0031] Next, the flat plate-like primary molded product 5 is supplied to a roll processing device and molded into a cylindrical shape. Specifically, four lines (lines A to D consisting of an extrusion molding machine 71 and a conveyor 81 shown in Fig. 6) for manufacturing the primary molded product 5 are prepared, and a roll processing device 61 as shown in Fig. 7 is prepared, and the primary molded product 5A manufactured by line A, the primary molded product 5B manufactured by line B, the primary molded product 5C manufactured by line C, and the primary molded product 5D manufactured by line D are continuously supplied to the roll processing device 61 and molded.

[0032] As shown in Figure 7, the roll processing device 61 is composed of a winding shaft 62, a motor 63, side edge guides 64 (first side edge guide 64A to fourth side edge guide 64D) that abut against the side edges of the supplied primary molded products 5A to 5D and guide the primary molded products 5A to 5D in a spiral direction around the outside of the winding shaft 62, and outer guides 65 (first outer guide 65A to fourth outer guide 65D) that press the supplied primary molded products 5A to 5D from the radial outside of the winding shaft 62.

[0033] The winding shaft 62 is connected to the drive shaft of a motor 63 and is configured to rotate in a predetermined direction by the driving force of the motor 63. The side edge guide 64 is made by curving a C-shaped metal plate into a spiral shape, and is disposed and fixed so as to surround the outside of the winding shaft 62.

[0034] In addition, a gap having a dimension smaller than the thickness of one layer of the primary molded product 5 (5 mm in this embodiment) is formed between the inner peripheral portion of the first side edge guide 64A and the outer peripheral surface of the winding shaft 62, a gap having a dimension larger than the thickness of one layer of the primary molded product 5 and smaller than the thickness of two layers (20 mm in this embodiment) is formed between the inner peripheral portion of the second side edge guide 64B and the outer peripheral surface of the winding shaft 62, a gap having a dimension larger than the thickness of two layers of the primary molded product 5 and smaller than the thickness of three layers (35 mm in this embodiment), and a gap having a dimension larger than the thickness of three layers of the primary molded product 5 and smaller than the thickness of four layers (50 mm in this embodiment) is formed between the inner peripheral portion of the fourth side edge guide 64D and the outer peripheral surface of the winding shaft 62.

[0035] The outer guide 65 is formed by curving a metal plate into a gutter shape, and is positioned so as to surround the lower side of the winding shaft 62 at a position spaced a certain distance from the outer peripheral surface of the winding shaft 62 (see first side edge guide 64A and first outer guide 65A in Figure 8).

[0036] Furthermore, the gap between the first outer guide 65A and the winding shaft 62 is set to the same dimension (within ±3 mm) as the thickness of one layer of the primary molded product 5, the gap between the second outer guide 65B and the winding shaft 62 is set to the same dimension (within ±3 mm) as the thickness of two layers of the primary molded product 5, the gap between the third outer guide 65C and the winding shaft 62 is set to the same dimension (within ±3 mm) as the thickness of three layers of the primary molded product 5, and the gap between the fourth outer guide 65D and the winding shaft 62 is set to the same dimension (within ±3 mm) as the thickness of four layers of the primary molded product 5.

[0037] The primary molded products 5A to 5D are continuously supplied to the roll processing device 61 configured as described above. Specifically, the primary molded product 5A manufactured by the line A shown in FIG. 7 is supplied obliquely to the winding shaft 62 and enters the gap between the winding shaft 62 and the first outer guide 65A. At this time, as shown in FIG. 9, the left side edge of the primary molded product 5A is supplied so as to enter along the first side edge guide 64A. Then, the primary molded product 5A is guided by the first side edge guide 64A and the first outer guide 65A, and is spirally wound around the outside of the winding shaft 62 as shown in FIG. 10, and the innermost monofilament roll 2a shown in FIG. 1 is formed.

[0038] This monofilament roll 2a is sequentially sent to the tip side (right side in FIG. 10) of the winding shaft 62 as the succeeding primary molded product 5A is spirally wound around the winding shaft 62. Then, when the tip portion passes through the area inside the second side edge guide 64B and the second outer guide 65B shown in FIG. 7, the gap between the second outer guide 65B and the outer peripheral surface of the monofilament roll 2a becomes about 15 mm (approximately the same dimension as the thickness of one layer of the primary molded product 5).

[0039] Next, the primary molded product 5B manufactured by line B is supplied obliquely to the winding shaft 62 in the same manner as the primary molded product 5A, and is caused to enter the gap between the monofilament roll 2a and the second outer guide 65B. At this time, as shown in Fig. 11, the primary molded product 5B is supplied so that the left side edge enters along the second side edge guide 64B. Then, as shown in Fig. 12, the primary molded product 5B is spirally wound around the outside of the monofilament roll 2a, and the second layer of monofilament roll 2b is formed from the inside as shown in Fig. 1.

[0040] This monofilament roll 2b and the monofilament roll 2a inside it are sequentially sent toward the tip side (right side in Figure 12) of the winding shaft 62 as the subsequent primary molded products 5A, 5B are wound around them, and when their tip portions pass through the inner area of ​​the third side edge guide 64C and the third outer guide 65C shown in Figure 7, the gap between the third outer guide 65C and the outer peripheral surface of the monofilament roll 2b becomes approximately 15 mm (approximately the same dimension as the thickness of one layer of the primary molded product 5).

[0041] In the same manner, the primary molded product 5C manufactured by the line C is inserted into the gap between the monofilament roll 2b and the third outer guide 65C to form the monofilament roll 2c on the outside of the monofilament roll 2b, and the primary molded product 5D manufactured by the line D is inserted into the gap between the monofilament roll 2c and the fourth outer guide 65D to form the monofilament roll 2d on the outside of the monofilament roll 2c (see FIG. 13). In this manner, by continuously supplying the primary molded products 5A to 5D to the roll processing device 61, a cylindrical water-permeable material consisting of the monofilament rolls 2a to 2d can be manufactured.

[0042] Furthermore, a line for supplying a water-permeable sheet 3 (nonwoven fabric) can be arranged between any two of the lines A to D for producing primary molded products, for example, between the line B for producing the primary molded product 5B and the line C for producing the primary molded product 5C, and the water-permeable sheet 3 can be supplied so that it can be wrapped around the outer surface of the monofilament roll 2b as shown in Figure 13, and the primary molded product 5C can be further wrapped around the outside thereof to form the monofilament roll 2c, thereby producing a cylindrical water-permeable material 1 having a cross section as shown in Figure 1 (i.e., a cylindrical water-permeable material 1 composed of four layers of monofilament rolls 2a to 2d and the water-permeable sheet 3 arranged between the monofilament rolls 2b and 2c).

[0043] Furthermore, as shown in FIG. 13, by arranging feed rollers 66 at positions where they can come into contact with the outer peripheral surfaces of the monofilament rolls 2c, 2d and supplying driving force to these feed rollers 66 to rotate them in a predetermined direction, the molded product can be smoothly sent out to the tip side of the winding shaft 62 (the right side in FIG. 13).

[0044] The cylindrical water-permeable material discharged from the roll processing device 61 is transported to a cooling device (air cooling device, cooling water tank, etc.) and cooled. Then, it is cut at a position of the desired length. If the monofilaments whose insides and surfaces are unhardened are brought into contact with each other immediately after extrusion molding and cooled in that state, the contacting parts will be bonded to each other. Therefore, the cylindrical water-permeable material manufactured by the above-mentioned method has sufficient rigidity as a whole and can maintain a stable shape because a large number of entangled monofilaments are bonded and integrated at a large number of points.

[0045] It is also possible to carry out a step of heating the primary molded product 5 before feeding it to the roll processing device 61, or a step of heating the cylindrical water-permeable material after it is discharged from the roll processing device 61. In this case, the contact portions of the entangled monofilaments can be more reliably bonded and integrated by thermal welding.

[0046] Moreover, by using a roll processing device 61 capable of wrapping one or more primary molded products around the outer side of the monofilament roll 2d shown in Fig. 13, it is possible to produce a cylindrical water-permeable material made of a monofilament roll having five or more layers. Moreover, by supplying only the primary molded products 5A, 5B (or the primary molded products 5A to 5C) to the roll processing device 61, it is also possible to produce a cylindrical water-permeable material having a two-layer structure (or a three-layer structure).

[0047] In this embodiment, high density polyethylene powder is used as the main raw material of the monofilament, but crosslinked high density polyethylene and an antifogging agent (functional agent for plastic molding) can also be mixed (in powder form) as auxiliary raw materials with this main raw material. The mixture of the main raw material and the auxiliary raw materials can be 60 to 80 parts by weight (preferably 70 parts by weight) of high density polyethylene, 20 to 40 parts by weight (preferably 30 parts by weight) of crosslinked high density polyethylene, and 4 to 10 parts by weight (preferably 7 parts by weight) of the antifogging agent.

[0048] Since crosslinked high-density polyethylene has different properties (fluidity, etc.) from high-density polyethylene, when crosslinked high-density polyethylene (auxiliary raw material) is blended with high-density polyethylene (main raw material) in the above ratio and extrusion molding is performed, the crosslinked high-density polyethylene in the synthetic resin raw material is extruded from the die of the extruder in a stretched molecular state. When the synthetic resin (monofilament) extruded from the die comes into contact with air, partial "shrinkage" occurs due to the temperature difference, and as a result, a large number of small irregularities with a height or depth of about 0.1 to 0.5 mm are formed on the surface, and the entire surface is not smooth but is configured as a rough surface and is randomly twisted, and it is expected that the tensile strength and compressive strength of the molded monofilament will be improved.

[0049] In addition, when 4 to 10 parts by weight of an anti-fogging agent, which is a functional agent for plastic molding, is blended as an auxiliary raw material, the blended surfactant etc. bleeds out, making the surface of the monofilament constituting the water-permeable material hydrophilic and weakening the water repellency. Therefore, when a water-permeable material is manufactured using a monofilament blended with an anti-fogging agent, it is expected that the compatibility with water will improve and the drainage performance will be improved. [Explanation of symbols]

[0050] 1: Cylindrical permeable material, 2a to 2d: monofilament rolls, 3: Permeable sheet, 5,5A~5D: Primary molded product, 11: Monofilament, 61: Roll processing device, 62: winding shaft, 63: Motor, 64: Side edge guide, 64A: First side edge guide, 64B: second side edge guide, 64C: Third side edge guide, 64D: Fourth side edge guide, 65: Outer guide, 65A: First outer guide, 65B: second outer guide, 65C: Third outer guide, 65D: Fourth outer guide, 66: Feed roller, 71: Extrusion molding machine, 72: Die, 73: Small hole, 81: Conveyor, 82: Press belt roller, 83: Side guide, A~D: Primary molding production lines

Claims

1. The whole has a cylindrical shape, The roll is made up of at least two layers of monofilament rolls stacked in the radial direction, Each monofilament roll is a cylindrical permeable material characterized in that multiple synthetic resin monofilaments are randomly curved or bent in three dimensions and entangled, and formed into a cylindrical shape with numerous continuous voids inside.

2. 2. The cylindrical water-permeable material according to claim 1, wherein four or more monofilament rolls are stacked in the radial direction.

3. 3. The cylindrical water-permeable material according to claim 1 or 2, characterized in that a water-permeable sheet is disposed between the two laminated monofilament rolls.

4. At least two lines are provided for manufacturing a flat-plate-like primary molded product having continuous voids therein by randomly curving or bending a plurality of synthetic resin monofilaments having a diameter of 1 to 3 mm extruded from an extrusion molding machine and entangling the monofilaments with each other in three dimensions, and A roll processing device is provided that has a winding shaft that is connected to a drive shaft of a motor and is configured to rotate in a predetermined direction by the driving force of the motor; A primary molded product manufactured on one line is supplied obliquely to a winding shaft and spirally wound around the outside of the winding shaft to form a monofilament roll of a first layer. A method for manufacturing a cylindrical water-permeable material, characterized in that a primary molded product produced on another line is supplied obliquely to the winding axis and spirally wound around the outside of the first layer of monofilament roll to form a second layer of monofilament roll.

5. The roll processing device has a side edge guide that comes into contact with a side edge of the primary molded product to be supplied and guides the primary molded product in a spiral direction, and an outer guide that presses the primary molded product to be supplied from the radially outer side of the winding shaft, the side edge guide has a helically curved shape, is arranged and fixed so as to surround the outside of the winding shaft, and is configured to abut against a side edge of the primary molded product to guide the primary molded product in a helical direction around the outside of the winding shaft; the outer guide has a gutter-like curved shape, is disposed and fixed so as to partially surround the winding shaft at a position spaced a certain distance from the outer circumferential surface of the winding shaft, and is configured to press the supplied primary molded product from the radially outer side of the winding shaft; A method for manufacturing a cylindrical water-permeable material as described in claim 4, characterized in that the primary molded product is supplied so that its side edge is aligned with the side edge guide, and is inserted into the gap between the outer guide and the winding shaft, or the gap between the outer guide and the inner monofilament roll, and then wound.

6. A method for manufacturing a cylindrical water-permeable material as described in claim 5, characterized in that a line for supplying a water-permeable sheet is arranged between any two of a plurality of lines for manufacturing primary molded products, the water-permeable sheet is wrapped around the outer surface of a monofilament roll formed from primary molded products supplied from one line, and then a primary molded product supplied from another line is wrapped around the outer surface of the water-permeable sheet, thereby arranging the water-permeable sheet between two stacked monofilament rolls.

7. The method for manufacturing a cylindrical water-permeable material according to any one of claims 4 to 6, characterized in that a feed roller is disposed at a position where it can contact the outer peripheral surface of the monofilament roll, and a driving force is supplied to the feed roller to rotate it in a predetermined direction, thereby sending out a molded product to the tip side of the winding shaft.

Images