JP2009297660A - Impermeable liner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impermeable liner of multilayered structure spreadable without causing large displacement even on a steep slope. <P>SOLUTION: The impermeable liner 1 of multilayered structure 1 is provided with protective layers 3, 3 consisting of nonwoven fabric on both sides of a synthetic resin impermeable layer 2. An adhesive-containing layer 4 of 3-15 mm thickness formed by fixing fibers with an adhesive is formed on the protective layers 3, with apparent specific gravity set to 0.03-0.15 kg/m<SP>3</SP>by applying press welding. The thickness of the adhesive-containing layer 4 is set to 1/4 or more of the thickness of the protective layer 3. A slip preventive layer 5 is formed on the outer surface of the protective layer 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a water-proof sheet having a multilayer structure in which a non-woven protective layer is provided on both surfaces of a water-proof layer, and more particularly to a water-proof sheet suitable for a waste final disposal site having a steep slope.

  In order to prevent the water-insulating sheets laid at the final disposal site, etc., from directly coming into contact with the waste, etc. Alternatively, a water shielding sheet is formed in a multilayer structure, and a water shielding layer and a protective layer are integrally formed.

  For example, in the former case, a protective sheet is disclosed in which a sheet obtained by needle punching a polyester fiber web is thermally bonded to both surfaces of a plastic film (Patent Document 1). In the latter case, polyvinyl chloride is disclosed. A water shielding sheet formed by thermally welding a polyester nonwoven fabric (protective layer) on both surfaces of a resin sheet (water shielding layer) is disclosed (Patent Document 2).

If the laid water barrier sheet is damaged, it will be difficult to recover if the soil leaks from it and the soil is contaminated, and it is not easy to find and repair the damaged part of the water barrier sheet. The thickness of the protective sheet and the protective layer that protects the water shielding sheet is increasing year by year.
Japanese Patent Laid-Open No. 2000-263209 JP 2006-159516 A

  In recent years, attempts have been made to increase the volume of the final disposal site by steep slope so that as much waste as possible can be disposed in a small area.

  However, when the slope of the slope becomes steep, there arises a problem that the water shielding sheet laid on the slope is easily displaced.

  In particular, the protective sheet of the nonwoven fabric is easily displaced from the beginning, and when the thickness is increased, the amount of the displacement is further increased. Therefore, a local load is applied to the laid water-impervious sheet, which may cause damage.

  For example, FIG. 5 conceptually shows a multi-layered water shielding sheet 10 in which protective layers 30 and 30 of a relatively large nonwoven fabric are integrally formed on both surfaces of the water shielding layer 20, respectively. When such a water shielding sheet 10 is laid on a slope N having a steep slope (for example, 1: 2 slope or more), as shown in FIG. Is greatly deformed, and a deviation occurs in which the outer surface side of the water shielding sheet 10 is displaced below the slope N.

  If it becomes so, it will be in the state where the water shielding sheet 10 will be crushed in the lower end part of the slope N, a local load will be added to the water shielding layer 20, and the possibility that the water shielding sheet 10 will be damaged from there will become high.

  The present invention has been made in view of the above points, and the object of the present invention is to provide a method in which the occurrence of deviation can be effectively suppressed even when the thickness of the protective layer is somewhat thick and the gradient is steep. An object of the present invention is to provide a water-proof sheet having a multilayer structure that can be laid without causing a large displacement with respect to the surface.

  In order to achieve the above object, in the present invention, an adhesive-containing layer having a predetermined thickness is formed on a protective layer made of a nonwoven fabric and subjected to a pressure contact treatment.

Specifically, the present invention is a water shielding sheet having a multilayer structure comprising a water shielding layer and a protective layer made of a nonwoven fabric provided on each of both surfaces of the water shielding layer, At least one of them has an adhesive-containing layer having a predetermined thickness in which fibers are fixed with an adhesive, and is subjected to a pressure-contact treatment so that an apparent specific gravity is within a range of 0.03 to 0.15 kg / m ^3. It is characterized by being set.

  As described above, when the adhesive-containing layer in which the fibers of the nonwoven fabric are fixed with an adhesive is formed, the protective layer is hardened and hardly deformed, so that the shape is stable and the shift is difficult to occur.

  Then, by pressing the protective layer with a roll or the like and pressing it so that the apparent specific gravity becomes the above-mentioned predetermined value, the balance between the hardness and the softness of the protective layer is in an appropriate state. Can be adjusted.

  The thickness of the protective layer having the adhesive-containing layer is preferably set to 3 to 15 mm. If the thickness is too small, the protective function of the water shielding layer is lacking. On the other hand, if the thickness is too large, it is difficult to wind the sheet into a roll, resulting in poor workability and high material costs.

  The adhesive-containing layer is preferably formed in a portion extending from the outer surface to the inner side in the thickness direction of the protective layer, and the thickness is preferably ¼ or more of the thickness of the protective layer.

  If it does so, since the outer surface of the protective layer which a waste etc. directly contacts becomes hard, it is effective when protecting a water shielding layer. Moreover, generation | occurrence | production of a shift | offset | difference can be effectively suppressed because the thickness of an adhesive content layer shall be 1/4 or more of the thickness of a protective layer.

  In the adhesive-containing layer, it is preferable to form a concentration gradient in which the adhesive content decreases from the outer surface toward the inner side.

  By doing so, the inner side connected to the water shielding layer becomes relatively soft and the action of external force transmitted to the water shielding layer is reduced, while the outer surface side of the protective layer becomes relatively hard and hardly shifts. Therefore, it is possible to reduce the amount of deviation as a whole protective layer while combining the hardness and softness of the protective layer in a well-balanced manner. In addition, although it is preferable that the content of the adhesive gradually decreases, there may be a case where the content decreases gradually, or a case where the content on the outer surface side is substantially the same and decreases from the middle.

  The adhesive-containing layer can be formed in a predetermined region in the vertical and horizontal directions of the protective layer, but is preferably formed on substantially the entire surface of the protective layer. If it does so, shift | offset | difference can be suppressed stably in any site | part of a protective layer.

  The protective layer is preferably fixed to substantially the entire surface of the water shielding layer. If the protective layer is partially fixed to the water shielding layer, the external force that acts on the protective layer acts particularly strongly on the fixed portion. In this case, the acting external force is dispersed throughout the water shielding layer, and the burden on the water shielding layer can be reduced accordingly.

  An anti-slip layer in which a large number of mineral particles are fixed to the fiber is preferably formed on the outer surface of the protective layer. If it does so, it can fix firmly also with respect to the slope with a steep slope, and generation | occurrence | production of the shift | offset | difference of the water-shielding sheet itself can be suppressed.

  As described above, according to the water-impervious sheet of the present invention, by forming an adhesive-containing layer in the protective layer, even when the thickness of the protective layer is somewhat increased, the occurrence of deviation is effectively suppressed. It can be laid without causing a large shift even on a slope with a steep slope.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  The water-impervious sheet 1 of this embodiment is shown in FIGS. This water-impervious sheet 1 is adjusted for a waste landfill site in a landfill site created by reclaiming the sea, and has a width of, for example, about 2 m so that it can be provided in a state of being wound around a roll. , And processed into a strip-like sheet having a length of several tens of meters. The cross section has a multilayer structure as shown in FIG. 1, and protective layers 3, 3 are integrally provided on both surfaces of the water shielding layer 2.

  This water shielding layer 2 is formed by processing a synthetic resin excellent in physical strength such as puncture strength and tensile strength, durability, waterproofness, and the like into a sheet shape. The type of synthetic resin is not particularly limited. For example, vulcanized rubber, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyurethane, polystyrene, polyvinyl acetate, polyamide, polyethylene terephthalate, ethylene / vinyl acetate copolymer, etc. It can be used suitably. Especially, since low density polyethylene can be used more preferably when cost and productivity are considered, low density polyethylene is used in this embodiment.

  However, the specific gravity of the synthetic resin used is preferably 1.05 or more. This is because, when the specific gravity is less than 1.05, it is difficult to sink in the water, so that the workability is lacking when the impermeable sheet 1 is laid in a water surface reclaimed land that may be submerged.

  Moreover, although the thickness of the water-impervious layer 2 depends on the type of the synthetic resin, it is preferably 3 to 5 mm. If the thickness is 3 mm or more, even if the thickness varies somewhat, the performance can be exhibited stably. However, if it exceeds 5 mm, it is difficult to wind it on a roll, the workability is insufficient, and the material cost is high. is there.

  The protective layer 3 is made of a nonwoven fabric composed of long fibers. The long fiber may be of any kind, such as inorganic fiber, semi-synthetic fiber, or synthetic fiber, but synthetic fiber is particularly preferable in view of productivity.

  Among synthetic fibers, for example, olefin fibers such as polypropylene and polyethylene, polyester fibers such as polyethylene terephthalate, polyamide fibers such as nylon, and acrylic fibers such as acrylonitrile can be suitably used. These can be used alone or in combination. In particular, polyester fibers can be used more preferably because they have a relatively large specific gravity and are inexpensive.

  The nonwoven fabric is preferably subjected to a hydrophilization treatment in order to make it easy to become familiar with water, so that when it is immersed in water, water easily enters the inside.

Basis weight mass of the protective layer 3 is preferably ^{300~1500g / m 2, 500~1000g / m} 2 is more preferable. By making the protective layer 3 relatively thick, the water shielding layer 2 can be reliably protected.

  The nonwoven fabric to be the protective layer 3 is formed by forming a web with long fibers, then performing needle punching so that the long fibers are entangled (entangled), and then impregnated with an adhesive, such as a smooth roll or an engraving roll. It is formed by pressing with a roll (pressure contact process).

  That is, each protective layer 3 is formed with an adhesive-containing layer 4 in which fibers are fixed with an adhesive in order to suppress the occurrence of deviation.

  In the adhesive-containing layer 4, it is preferable to form a concentration gradient in which the adhesive content gradually decreases from the outer surface to the inner surface side of the protective layer 3. By doing so, the inside of the protective layer 3 connected to the water shielding layer 2 becomes relatively soft, and the action of the external force transmitted to the water shielding layer 2 is relaxed, while the outer surface side of the protective layer 3 is relatively Therefore, the amount of deviation can be reduced as a whole of the protective layer 3.

  As the adhesive used here, any adhesive that enters the inside of the nonwoven fabric and adheres and solidifies the fibers can be used, and examples thereof include acrylic resin-based, vinyl resin-based, and rubber-based adhesives. And can be appropriately selected according to the type of the nonwoven fabric. Among them, if a hydrophilic adhesive having a high affinity with water, such as a water / emulsion adhesive, is used, the adhesive-containing layer 4 can be easily formed by well adapting to the hydrophilic treated nonwoven fabric. be able to.

  The adhesive-containing layer 4 can be formed on substantially the entire surface of the protective layer 3 by, for example, a method of spraying the adhesive with a spray or a method of applying the adhesive using a roll coater.

  The adhesive-containing layer 4 may be formed only on a part of the main surface in the vertical and horizontal directions of the protective layer 3, for example, a predetermined part dispersed and arranged at a predetermined interval, but is formed on substantially the entire surface. In this case, the shift can be stably suppressed at any part of the protective layer 3.

  For example, if the thickness of the protective layer 3 is 8 mm, the width dimension in the thickness direction of the adhesive-containing layer 4 is such that the protective layer 3 is formed from the outer surface of the protective layer 3 to 2 mm or more inside. It is set to be 1/4 or more of the thickness. For example, the width dimension may be increased and set to, for example, ½ or more of the thickness of the protective layer 3, so that the shift can be further suppressed and the protection of the water shielding layer 2 can be strengthened. Can do.

  Furthermore, a non-slip layer 5 having a high friction coefficient is formed on the outer surface of each protective layer 3 by fixing a large number of mineral particles such as silica sand and alumina to the fiber surface.

  The anti-slip layer 5 can be formed at the same time as the previous adhesive-containing layer 4 is formed. That is, if mineral particles are mixed with the adhesive for forming the adhesive-containing layer 4 and soaked into the outer surface of the protective layer 3, the adhesive soaks into the inside of the protective layer 3 through the gaps in the nonwoven fabric. However, the mineral particles are captured by the fibers on the outer surface of the protective layer 3 and fixed there by an adhesive.

Nonwoven fabric comprising a protective layer 3 is in the range that the apparent specific gravity of 0.03~0.15kg / ^{m 3} by press processing, particularly adjusted within the 0.05~0.10kg / ^{m 3} Has been. If it is less than 0.03 kg / m ³ , it is difficult to obtain sufficient strength even if the adhesive-containing layer 4 is formed, and there is a possibility that displacement cannot be effectively prevented, while 0.10 kg / m ³ is reduced. If it exceeds, it will be harder than necessary, making it difficult for water to penetrate, and the material cost will be high.

  Moreover, 3-15 mm is preferable and, as for the thickness of the protective layer 3, 5-10 mm is more preferable among these. If it is smaller than 3 mm, there may be a portion lacking in the protective performance due to variations in molding, while if it is larger than 15 mm, it becomes difficult to wind in a roll shape, and workability is inferior.

  The nonwoven fabric used as the protective layer 3 is fixed to the water shielding layer 2 by being thermally welded continuously when the water shielding layer 2 is formed.

  That is, in the present embodiment, although not shown in the drawing, a synthetic resin is extruded from a molding machine to form a sheet-shaped molded body that becomes the water shielding layer 2, and before the temperature of both surfaces of the sheet-shaped molded body is lowered and solidified, The nonwoven fabric used as the protective layer 3 is integrated by pressing on both surfaces. Therefore, since the protective layer 3 of the present embodiment is integrally fixed to substantially the entire surface of the water shielding layer 2, the external force acting on the water shielding layer 2 via the protective layer 3 is dispersed throughout the water shielding layer 2. Therefore, the burden on the water shielding layer 2 can be reduced accordingly.

  By the way, in the conventional water-proof sheet 10 having a multilayer structure, since the sheet to be the water-proof layer 20 and the nonwoven fabric to be the protective layer 30 are separately formed and then both are partially bonded and integrated, A local burden is easily applied to the water layer 20.

  FIG. 2 shows the results of examining the relationship between the load amount in the displacement direction and the displacement amount in the displacement direction of the water-impervious sheet 1 for the water-impervious sheet 1 of the present embodiment. In FIG. 2, the solid line is the water-impervious sheet 1 of the present embodiment, the broken line is a conventional water-impervious sheet 10 (with a non-slip layer) as a comparative control, and the two-dot chain line is the conventional water-impervious sheet 10 (slip No stop layer).

  As shown in the figure, in the conventional water-impervious sheet 10 (without the anti-slip layer), since the frictional force on the surface of the protective layer 30 is low, it slips when the load is slightly increased, for example, on a slope with a steep slope. It is difficult to hold waste etc. on the surface.

  On the other hand, in the case of the conventional water-impervious sheet 10 (with a non-slip layer), the frictional force on the surface of the protective layer 30 is improved. The displacement deformation occurs, and the water-impervious layer 20 is greatly displaced in the displacement direction (see FIG. 5).

  In that respect, in the water-impervious sheet 1 of the present embodiment, the displacement amount of the water-impervious layer 2 is smaller than the conventional water-impervious sheet 10 (with a non-slip layer), and the displacement is suppressed. I was able to confirm that I could do it.

  In FIG. 3, the schematic of the state which laid this water-impervious sheet 1 in the waste final treatment plant of a water surface reclaimed land is shown.

  The water-impervious sheet 1 is, for example, formed by joining a plurality of water-impervious sheets 1, 1,... The

  In recent years, it has been attempted to increase the volume of the final disposal site by steeply increasing the slope of the slope N. As shown in the figure, the slope N has a steep slope of 1: 2 or higher. May be laid.

  In this case, when the waste or the like is placed on the water-impervious sheet 1 laid on the slope N, the waste or the like is held at the position without slipping by the action of the anti-slip layer 5. A load that pulls downward along the slope N is applied to the outer surface of.

  On the other hand, first, since the water shielding sheet 1 is firmly fixed to the ground surface of the slope N by the anti-slip layer 5 formed on the outer surface of the protective layer 3, the sliding of the water shielding sheet 1 itself is prevented. be able to. And since the shift deformation of the protective layer 3 is suppressed by the adhesive-containing layer 4 formed inside the protective layer 3, the shift amount of the water shielding sheet 1 is suppressed as shown in FIG.

  Therefore, it can suppress that the impermeable sheet 1 slip | deviates below the slope N, and a local load is added to the impermeable layer 2 in the lower end part of the slope N, and the impermeable sheet 1 is damaged from there. Can be effectively prevented. Furthermore, since the water shielding layer 2 can be effectively protected from waste and the like by the thickness of the protective layer 3 and the strength of the adhesive-containing layer 4, it is safer to lay this water shielding sheet 1. A highly reliable waste final treatment plant can be realized.

  In addition, the water shielding sheet | seat concerning this invention is not limited to the said embodiment, The other various structure is included. That is, in the above embodiment, the protective layer 2 is formed by the needle punch method, but other mechanical entanglement means may be used or may be used without being entangled. Further, in the above embodiment, the adhesive-containing layer 4 is formed at the time of forming the nonwoven fabric to be the protective layer 2. However, after the nonwoven fabric having a predetermined shape is once formed, the adhesive-containing layer is separately impregnated with the adhesive. 4 may be formed.

It is the schematic which shows the cross section of the water shielding sheet of this invention. It is the schematic which shows the relationship between the load amount and displacement amount to the water-impervious sheet of this invention. It is the schematic which shows the state which laid the water-impermeable sheet of this invention in the waste final treatment plant. It is a conceptual diagram at the time of applying a load to the water shielding sheet of the present invention. It is a conceptual diagram at the time of applying load to the conventional water shielding sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water shielding sheet 2 Water shielding layer 3 Protective layer 4 Adhesive containing layer 5 Anti-slip layer

Claims (7)

A water shielding sheet having a multilayer structure comprising a water shielding layer and a protective layer made of a nonwoven fabric provided on each of both surfaces of the water shielding layer,
At least one of the protective layers has an adhesive-containing layer having a predetermined thickness in which fibers are fixed with an adhesive, and is subjected to a pressure-contact treatment to give an apparent specific gravity of 0.03 to 0.15 kg / m ^3. A water-proof sheet characterized by being set within the range. The water shielding sheet according to claim 1,
The water shielding sheet, wherein the thickness of the protective layer having the adhesive-containing layer is set to 3 to 15 mm. In the water shielding sheet according to claim 2,
The adhesive-containing layer is formed in a portion extending from the outer surface to the inner side in the thickness direction of the protective layer, and the thickness is ¼ or more of the thickness of the protective layer. Water sheet. In the impermeable sheet of Claim 3,
The water-impervious sheet, wherein the adhesive-containing layer is formed with a concentration gradient in which the content of the adhesive decreases from the outer surface toward the inner side. In the water shielding sheet according to claim 4,
The waterproof sheet, wherein the adhesive-containing layer is formed on substantially the entire surface of the protective layer. In the impermeable sheet as described in any one of Claims 1-5,
The water shielding sheet, wherein the protective layer is fixed to substantially the entire surface of the water shielding layer. In the impermeable sheet as described in any one of Claims 1-6,
An anti-slip layer in which a large number of mineral particles are fixed to fibers is formed on the outer surface of the protective layer.

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