JP2013212505A - Waste coating capping sheet and its joining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste coating capping sheet reduced in a variation of a water intrusion amount even if a laying condition such as a rainfall amount and a slope gradient is varied, and to provide the capping sheet by which a water permeation amount suitable for a site can easily be obtained by changing its front and rear surfaces.SOLUTION: A waste coating water-permeable capping sheet has a laminated structure of at least two layers composed of a first fiber sheet and a porous sheet. The capping sheet is the waste coating capping sheet whose unit weight is 80 to 1,200 g/m, in which respective water permeation factors of both faces of the capping sheet measured by a JIS A1218 (1998) 5 method (constant water level water permeation test) are 1×10to 1×10cm/s, respectively, and a value at the face higher in water permeation factor out of both the respective faces of the capping sheet is larger than a value at the face lower in water permeation factor by 50% or more.

Description

  The present invention relates to a capping sheet used in a waste disposal site or an illegal dumping site.

  Conventionally, in landfills, after landfilling waste, in order to achieve “stabilization” of waste by flowing appropriate rainwater into the landfill pit, the landfill area is capped with a capping sheet, etc. The surface is covered with soil. Since the waste covering capping sheet is generally installed on a sloping slope, it is possible to discharge excess rainwater more than necessary for stabilizing the waste. In addition, it is desired that there is appropriate air permeability in order to remove gas generated from waste. Furthermore, at the illegal dumping site, it is necessary to prevent the pollutant from flowing out by rainwater before being transferred to the disposal site. In order to achieve such an object, for example, Patent Document 1 discloses a capping structure and construction method with controlled water permeability. Patent Documents 2 and 3 disclose a method of controlling air permeability of a composite of a nonwoven fabric serving as a base layer and a water-impervious film or an extremely water-permeable sheet (melt blown nonwoven fabric) by needle punching.

JP 2006-116512 A JP 2003-286737 A JP 2004-21037 A

  However, when the hydraulic conductivity of the capping sheet is constant, there is a possibility that the amount of infiltrated water passing through the capping sheet may vary due to the variation in rainfall. In addition, there is a possibility that the amount of inundation will fluctuate when the slope changes. An object of the present invention is to provide a capping sheet in which the fluctuation of the intrusion water amount is small even when the laying conditions such as the rainfall amount and the slope of the slope fluctuate. Furthermore, it is an object of the present invention to provide a capping sheet that can easily obtain a water permeability suitable for the place by changing the front and back sides.

The capping sheet for waste coating according to the present invention that achieves the above object is as follows.
1. A water-permeable capping sheet for waste covering having a laminated structure of at least two layers, comprising a first fiber sheet and a porous sheet,
The capping sheet has a basis weight of 80 to 1200 g / m ² , and the water permeability coefficients of both sides of the capping sheet measured by JIS A1218 (1998) 5 method (constant water level permeability test) are both 1 × 10 ⁻⁷ to 1 A waste-covering capping sheet that is × 10 ⁻³ cm / s and has a value of 50% or more greater on the surface of the capping sheet having a higher water permeability than the surface of the lower surface.
2. 2. The water-permeable capping sheet for waste coating according to 1 above, wherein the second fiber sheet is laminated on the opposite side of the first fiber sheet.
3. 3. The waste coating capping sheet according to 1 or 2 above, wherein the porous sheet is a porous sheet having 0.1 to 14 holes having a diameter of 1.0 mm or less per 1 cm ² .
4). Any one of the above 1-3, wherein the first fiber sheet is a thermocompression-bonded long fiber nonwoven fabric made of at least one resin selected from the group consisting of polyolefin resin, polyester resin, and polyamide resin. Capping sheet for waste coating.
5. The first fiber sheet is a light blocking ratio of 90% or more, the waste coating capping sheet according to any one basis weight of 1 to 4 above are 70~500g / ^{m 2.}
6). Any of the above 2 to 5, wherein the second fiber sheet is a nonwoven fabric produced by a needle punch method having a thickness of 0.2 to 10.0 mm, a basis weight of 50 to 1000 g / m ² , and a penetration resistance of 200 N or more. The capping sheet for waste covering as described.
7. When laid on a slope with a slope of 3% to 5%, even if the rainfall increases from 10 mm / hour to 40 mm / hour, the infiltration amount does not increase more than three times. Waste capping sheet.
8). A joining method in which the capping sheet according to any one of the above 1 to 7 is joined with a tape made of modified asphalt, followed by covering with a soil of 30 to 100 cm.

  According to the present invention, it is possible to provide a capping sheet in which the fluctuation of the intrusion water amount is small even when the laying conditions such as the rainfall and the slope of the slope fluctuate. Furthermore, by changing the front and back sides, it is possible to provide a capping sheet that is easy to obtain a water permeation amount suitable for a laying place while being the same product.

The capping sheet for waste coating of the present invention is a water permeable capping sheet for waste coating having a front and back asymmetric structure having a laminated structure of at least two layers composed of a first fiber sheet and a porous sheet with controlled water permeability. There,
The capping sheet has a basis weight of 80 to 1200 g / m ² , and both of the water permeability coefficients of both sides (front and back) of the capping sheet measured according to JIS A1218 are 1 × 10 ⁻⁷ to 1 × 10 ⁻³ cm / Furthermore, it is characterized in that the value of the surface with the higher water permeability of each of both surfaces (front surface and back surface) of the capping sheet is 50% or more larger than the value of the lower surface.

First, preferable characteristics of the first fiber sheet will be described.
The resin constituting the fiber used for the first fiber sheet is not particularly limited, but includes at least one resin selected from the group consisting of polyolefin resins, polyester resins, and polyamide resins. It is preferable. Among these, polyester resins are particularly preferable because they are excellent in weather resistance and mechanical strength characteristics. In addition, as the material resin of the constituent fibers, one material may be used alone, or fibers made of two or more kinds of resins may be mixed and used. Further, the fiber may be a single component or a bicomponent composite fiber. The thickness of the fiber is not particularly defined, but preferably the single yarn fineness is between 2.2 and 11 dtex. The fiber sheet may be a woven fabric, but a non-woven fabric that does not require cutting edge treatment is preferable, and a long-fiber non-woven fabric excellent in mechanical properties is particularly preferable. Further, as a fiber fixing and entanglement method, a needle punch method or a spun lace method may be used, but it is preferable to apply a thermocompression bonding method in which fluff does not easily come out when an operator walks on the fiber. Although the whole may be bonded by thermocompression bonding, partial bonding is more preferable for improving the tearing property. In addition, fixing the fiber with a binder resin or the like is also recommended.

  The first fiber sheet preferably has a light shielding rate of 90% or more. This is preferable in increasing the weather resistance of the first fiber sheet itself, and is also preferable in terms of preventing ultraviolet deterioration of the porous sheet. In order to ensure the light shielding rate, a colored one is preferable. As the dye to be used, a dye which is difficult to mutate during spinning is preferable. Specific examples include carbon black and inorganic pigments. Although there is no restriction | limiting in particular about a hue, Usually, since the 1st fiber sheet side colored with this pigment | dye becomes the outermost surface, the pigment | dye which becomes a suitable color according to the place where the capping sheet of this invention is applied. Just choose. Therefore, the coloring matter may be used alone, or a plurality of types may be mixed and used in order to adjust the hue.

Also, the basis weight of the first fiber sheet is preferably 70~500g / ^{m 2,} and more preferably 100 to 200 g / ^{m 2.} If the basis weight is less than 70 g / m ² , it is necessary to be careful because an operator or heavy machinery may be damaged when moved on the capping sheet. On the other hand, if the basis weight exceeds 500 g / m ² , workability may be deteriorated or it may be difficult to follow the unevenness of the ground, which is not preferable.

A fibrous or dot-like resin may be attached to the nonwoven fabric surface for the purpose of preventing slippage of people or soil. Mixing an inorganic material such as sand with resin is also one of the preferred forms for the purpose of improving the slip resistance in rainy weather. The non-slip material attached amount is preferably 15 to 100 / ^{m 2,} and more preferably 25~60g / ^{m 2.}

  Next, the porous sheet that contributes most to water permeability control in the present invention is preferably a non-woven fabric or a sheet made of ultrafine fibers produced by a melt-blowing method or a flash spinning method and having a hole in the film. There is no restriction | limiting in particular as a raw material which comprises the said porous sheet, According to the characteristic of a waste, it can select freely. For example, polyolefin resins such as polyethylene, polypropylene and ethylene-vinyl acetate copolymer (EVA); fluorine resins such as polytetrafluoroethylene and polyvinylidene fluoride are preferable, and low density polyethylene is particularly preferable. As such a porous sheet, for example, a commercial product such as Microtex (registered trademark) manufactured by Nitto Denko Corporation, Tetlatex (registered trademark) manufactured by Nippon Donaldson Co., Ltd. can be used, It is also possible to use an SMS (spunbond-meltblown-spunbond) nonwoven fabric which is a composite using flash-spun nonwoven fabric or ultrafine fibers.

In order to prevent damage to the porous sheet due to external force during laying, the porous sheet preferably has an appropriate elongation at break and tear strength.
The porous sheet preferably has a breaking elongation measured according to JIS L1906 of 250% or more, more preferably 300% or more, and further preferably 400% or more. The porous sheet preferably has a tear strength measured according to JIS K7128-1 of 0.75 N or more, more preferably 1.0 N or more, and 2.0 N or more. Further preferred.

When the porous sheet is a nonwoven fabric, high air permeability can be expected. The basis weight of the nonwoven fabric is preferably 20 to 150 g / m ² in order to reduce the in-plane water permeability or air permeability spots. If the basis weight is less than 20 g / m ² , problems such as large variations in physical properties depending on the in-plane location and low mechanical properties are likely to occur, which is not preferable. On the other hand, when the basis weight exceeds 150 g / m ² , there is a possibility that the voids of the nonwoven fabric may be blocked by foreign matters such as soil and dust brought together with water during water permeation.

When the porous sheet is a perforated film, the air permeability and moisture permeability can be increased as the aperture ratio is higher. In particular, a 0.1 to 1 μm microporous film that is generally used for ventilation sheets for sanitary materials such as diapers and napkins has high moisture permeability to keep waste aerobic and to aerobically decompose soil microorganisms. It is possible to promote and is particularly preferred. Examples of the method for producing a microporous sheet include a porous sheet in which fine particles are formed by mixing resin with inorganic fine particles such as calcium carbonate to form a sheet, and stretching the sheet. In particular, it is preferable to use a porous sheet manufactured by an inflation method. From experience, the porous sheet produced by the inflation method has good adhesion between the first fiber sheet and the second fiber sheet, which will be described later, and thus the waterproofness of the produced waste coating capping sheet is increased. is there. When the water permeability coefficient of the porous film is smaller than 10 ⁻⁷ cm / s, it is possible to control the water permeability by making a hole by a needle punch method or a hot needle penetration. The perforating process may be performed with the porous film alone, but in order to prevent the film from being broken or wrinkled, it is preferable to perform the perforating process after combining with at least the first fiber sheet. Further, it may be after being combined with the second fiber sheet.

  As a method of combining the porous sheet with the first fiber sheet and / or the second fiber sheet, a thermal laminating method, a frame laminating method, a curtain spraying method, or the like can be used. is not. Preferably, it is recommended to partially heat-bond using hot-melt powder or hot-melt fiber type adhesive.

When opening a hole by the needle punch method, it is preferable to use a 36 to 40th needle and to make a hole having a diameter of 1.0 mm or less. The needle may be a normal barb or may be a no kick type. When non-woven fabric is not combined, it is recommended to use a no-kick needle. It is possible to control the hydraulic conductivity by changing the hole density. In the range of investigation by the inventors, it is possible to set a desired permeability coefficient at a puncture density of 0.1 to 14 locations / cm ² with a hole having a diameter of 1.0 mm or less, and particularly preferably 1 to 6. Location / cm ² . It is possible to obtain a desired water permeability even if a small hole is drilled at more than 14 locations / cm ² , but if the hole number density is too high, the difference in water permeability when the front and back sides are changed is small. There was a tendency, and the consistency with the object of the present invention tended to be low.

The thickness of the porous sheet is preferably 30 to 200 μm, particularly preferably 50 to 150 μm.
As the moisture permeability of the porous sheet, the moisture permeability measured in accordance with the JIS L1099 A-1 method is preferably 100 g / m ² · 24 hr or more, more preferably 1000 g / m ² · 24 hr or more. Preferably, it is 5000 g / m ² · 24 hr or more.

The second fiber sheet applicable to the present invention preferably has a thickness of 0.2 to 10.0 mm. Moreover, it is also preferable that a fabric weight is 50-1000 g / m < ² >. And it is preferable that it is the nonwoven fabric manufactured by the needle punch method whose penetration resistance measured according to prescription | regulation of ASTMD 4833 is 200N or more. The capping sheet is not always laid on a smooth ground, and a certain amount of thickness and a fiber amount (that is, basis weight) are necessary for cases where there are sharp projections on the waste. Further, the higher the penetration resistance to the protrusion, the better.

  In another preferred embodiment, the second fiber sheet uses a short fiber non-woven fabric provided with a hydrophilic oil agent or a hydrophobic oil agent in order to change wettability to water. Or you may dry by spraying a hydrophilizing agent by the spray method etc. to the long-fiber nonwoven fabric punched by needle. When long-term hydrophilicity is required, it is preferable to use a type of resin that reacts with and adheres to the fiber resin. A method of fixing using a cross-linked binder resin is also applicable.

Further, the waste coating capping sheet of the present invention has a basis weight of 80 to 1200 g / m ² . Preferably it is 300-800 g / m < ² >. If the basis weight is less than 80 g / m ² , the mechanical strength characteristics are insufficient, which is not preferable. On the other hand, when the weight per unit area exceeds 1200 g / m ² , it is not so preferable because it hinders transportation and laying and reduces the usable volume of the disposal site.

The capping sheet for waste coating according to the present invention has a moisture permeability of 100 g / m ² · 24 hr or more measured in accordance with the JIS L 1099 A-1 method from the viewpoint of ensuring moisture permeability and aerobic properties against microorganisms. It is preferably 1000 g / m ² · 24 hr or more, more preferably 3000 g / m ² · 24 hr or more. The moisture permeability of the capping sheet of the present invention is determined by the porous sheet.

Furthermore, the capping sheet of the present invention has a water permeability coefficient of 1 × 10 ⁻⁷ to 1 × 10 ⁻³ cm / s measured on both sides of the capping sheet according to JIS A1218 (1998) 5 method (constant water level water permeability test). Yes, it is necessary that the value of the surface with the higher water permeability of each side of the capping sheet is 50% or more larger than the value of the lower surface. If the water permeability coefficients of both sides of the capping sheet are both less than 1 × 10 ⁻⁷ cm / s, it is not preferred that aerobic decomposition hardly occurs. On the other hand, if it exceeds 1 × 10 ⁻³ cm / s, the possibility that contaminated water flows out to the outside due to excessive water entry is not preferable. Furthermore, if the value of the surface of the capping sheet with the higher coefficient of water permeability is not larger than 50% of the value of the lower surface, there will be little difference in the use of the front and back when the gradient changes, and the effect will be less preferable. . The reason why the water permeability coefficient changes on both sides is related to the hydrophilic property of the fiber sheet bonded to the porous sheet layer, the contact area of the sheet, and the thickness of the fiber sheet coming up. In general, the higher the asymmetry, the greater the difference in hydraulic conductivity. The larger the contact area with the sheet, the higher the sheet thickness, and the higher the hydrophilicity of the fiber sheet or porous sheet, the higher the water permeability coefficient.
In addition, within the scope of the study of the present inventors, as an example of a structure having the largest difference between both surfaces, a first fiber sheet made of a thermocompression type long fiber nonwoven fabric with a basis weight of 80 to 200 g / m ² and a basis weight of It was a combination of 150 to 500 g / m ² of needle punch method nonwoven fabric.

Furthermore, when the capping sheet of the present invention has an appropriate configuration, even when the rainfall amount increases from 10 mm / hour to 40 mm / hour when laid on a slope of about 3% to 5%, the infiltration amount is 3 It is possible not to increase more than twice. Within the scope of the study by the inventors, when the fiber sheet coming down during laying is thicker than 0.3 mm, the variation in the amount of permeation decreases, and the tendency increases as the thickness increases and the hydrophilicity increases. Particularly preferably, the thickness is 2.5 mm or more. The reason is presumed that water is retained in the fiber sheet by capillary suction. Therefore, it is considered that the smaller the fiber diameter and the narrower the fiber gap, the smaller the variation in the amount of penetration.

  The waste coating capping sheet of the present invention includes one obtained by joining a plurality of the waste coating capping sheets.

  As the most common joining method of the capping sheet of the present invention, a heat welding method using a leister or the use of an adhesive may be considered. Among them, it is easy to use an adhesive tape, and an acrylic resin, butyl rubber, or modified asphalt is preferably used as an adhesive substance. In view of durability and sealing properties, a modified asphalt tape is particularly preferable. By performing the covering of 30 to 100 cm, it becomes possible for the modified asphalt to enter the gap between the fibers constituting the fiber sheet by the load, thereby obtaining high sealing performance and bonding strength. In order to improve dimensional stability, it is particularly preferable to use a pressure-sensitive adhesive tape containing a base material.

  In order to obtain an appropriate joining force when joining using an adhesive tape, the thickness of the first fiber sheet is preferably 0.3 mm or more, and more preferably 0.4 mm or more. Moreover, it is preferable that thickness is 1.0 mm or less, and it is more preferable that it is 0.8 mm or less. When the thickness of the first fiber sheet is in the above range, water permeation at the joint is minimized when joining a plurality of waste coating capping sheets.

As an adhesive tape used for joining, it is also suitable to use an adhesive tape formed by forming an adhesive layer on one side of a fiber sheet. The material and forming method of the sheet constituting the adhesive tape are not particularly limited, and for example, the material and forming method exemplified for the first fiber sheet can be adopted. The sheet constituting the adhesive tape preferably has a basis weight of 100 g / m ² or more. If it is a sheet | seat of such a fabric weight, since it has a weather resistance, the abnormal change of an adhesive layer can be suppressed. From this point of view, it is recommended that the adhesive tape sheet is also colored in the same manner as the first fiber sheet. The details of coloring are as described above for the first fiber sheet. Furthermore, it is preferable that the sheet | seat of an adhesive tape is the same raw material and the same color as a 1st fiber sheet. The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is not particularly limited, and for example, a butyl rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a pressure-sensitive adhesive applied to a known cloth tape, or the like can be used.

  The joint portion preferably has a joint strength measured in accordance with JIS L1906 of 350 N / 5 cm or more, and more preferably 500 N / 5 cm or more. When the joint strength of the joint portion is 350 N / 5 cm or more, the waste covering capping sheet can minimize damage to the joint portion due to external force.

  The waste-covering capping sheet of the present invention is coated in accordance with the area of the waste dumping site with the non-slip fibrous surface facing outside, and is fixed by a known method (pinning or fixing with a heavy object). .

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples are not intended to limit the present invention, and all modifications made without departing from the spirit of the preceding and following descriptions are included in the technical scope of the present invention. The measurement method used in the present invention is as follows.

<Sheet weight of sheet>
Measured according to JIS L1906 (2000).

<Permeability coefficient>
Measured according to JIS A1218 (1998) 5 method (constant water level permeability test).

<Elongation at break>
Measured according to JIS L1906 (2000).

<Tear strength>
Measured according to JIS K7128-1 (1998).

<Shading rate>
Measured in accordance with JIS L1055 (1987) A method.

<Penetration resistance>
Measured according to ASTM D-4833.

<Moisture permeability>
Measured according to JIS L1099 (2006) A-1 method.

<Penetration amount when rainfall changes>
When laying on a 3% slope, artificial precipitation was performed intermittently with a sprayer every 15 seconds. The amount of infiltration when the rainfall increased from 10 mm / hour to 40 mm / hour was measured by model evaluation.

Example 1
As a 1st fiber sheet, the partial thermocompression long-fiber nonwoven fabric made of polyester colored black with carbon black (2.2 dtex, basis weight 130 g / m ² , thickness 0.5 mm, shading rate 99.8% or more) is used. It was. This lower surface of the first fiber sheet, as the porous sheet, a waterproof moisture-permeable film was formed by inflation method a polyethylene (manufactured by Tokuyama Corporation "Poramu" (TM) high weather and high elongation type: basis weight 100 g / m ² , Thickness 100 μm, elongation at break 530%, tear strength 2.1N, average value of longitudinal and transverse heat shrinkage at 80 ° C. 16%). The first fiber sheet and the waterproof and moisture-permeable sheet were laminated and integrated by an acrylic pressure-sensitive adhesive (Saiden Chemical TC-K3 resin manufactured by Saiden Chemical Co., Ltd.) by a curtain spray method. Next, needle punching with a 40th needle was performed at a puncture density of 3 spots / cm ² and a puncture depth of 14 mm. The diameter of the opened hole was 0.32 mm. Subsequently, as a second fiber sheet, a polyester needle punch long fiber non-woven fabric colored in black with carbon black (2.2 dtex, basis weight 300 g / m ² , thickness 3 mm, penetration resistance 800 N, shading rate 99.8% or more ) Was laminated on the waterproof and moisture-permeable sheet by the curtain spray method with the same acrylic adhesive. The basis weight of the laminate thus produced (waste covering capping sheet according to the present invention) was 550 g / m ² . When the water permeability was measured with the first fiber sheet surface facing up, it was 1.2 × 10 ⁻⁵ cm / s. When the front and back sides were reversed, it was 5.1 × 10 ⁻⁵ cm / s. The change in the amount of infiltration due to the precipitation change with a 3% gradient (increased from 10 mm / hour to 40 mm / hour) was 1.8 times.

(Example 2)
Needle punch processing was pierced to a density of 10 places / cm ² , polyester needle punched short fiber nonwoven fabric colored with black as a second fiber sheet (3.3 dtex, basis weight 500 g / m ² , thickness 6 mm A waste capping sheet was prepared under the same conditions as in Example 1 except that the penetration resistance was 1200 N and the light shielding ratio was 99.8% or higher. The basis weight of this waste coating capping sheet was 750 g / m ² . It was 7.9 * 10 < ^-5 > cm / s when the water permeability was measured for the 1st fiber sheet surface up. When the front and back sides were reversed, it was 1.2 × 10 ⁻⁴ cm / s. The change in the amount of infiltration due to the precipitation change with a 3% gradient (increased from 10 mm / hour to 40 mm / hour) was 2.2 times.

(Example 3)
Waste coating capping under the same conditions as in Example 1 except that a flash-spun nonwoven fabric (terminal fiber diameter of about 3 μm, basis weight 50 g / m ² , thickness 0.3 mm, shading rate 98% or more) was used as the porous sheet. A sheet was produced. The basis weight of this waste coating capping sheet was 500 g / m ² . Subsequently, a resin layer obtained by mixing acrylic resin with sand (about 40% by weight) and a green pigment on the second fiber sheet surface was applied by an about 80 g / m ² doctor knife method and dried. The air permeability was almost the same as the value before processing, probably because the porous sheet layer dominates. When the water permeability was measured with the first fiber sheet surface facing up, it was 3.2 × 10 ⁻⁵ cm / s. When the front and back sides were reversed, it was 5.1 × 10 ⁻⁴ cm / s. The change in the amount of infiltration due to the precipitation change with a 3% gradient (increased from 10 mm / hour to 40 mm / hour) was 2.6 times.

(Comparative Example 1)
Needle punching was carried out using an 18th needle to a piercing density of 15 spots / cm ² (the diameter of the opened holes was 1.05 mm), and the second fiber sheet was not used. As in Example 1, a waste coating capping sheet was produced. The basis weight of this waste coating capping sheet was 240 g / m ² . The waste capping sheet was measured and evaluated in the same manner as in Example 1. When the water permeability was measured with the first fiber sheet surface facing up, it was 2.1 × 10 ⁻³ cm / s. When the front and back sides were reversed, it was 2.5 × 10 ⁻³ cm / s. The change in the amount of infiltration due to the change in precipitation with a 3% gradient (increased from 10 mm / hour to 40 mm / hour) was 4.0 times.

(Comparative Example 2)
A waste coating capping sheet was prepared in the same manner as in Example 1 except that the second fiber sheet was made of the same long fiber nonwoven fabric as the first fiber sheet of Example 1. The basis weight of this waste coating capping sheet was 380 g / m ² . The waste coating capping sheet was measured and evaluated in the same manner as in Example 1. When the water permeability was measured with the first fiber sheet surface facing up, it was 1.2 × 10 ⁻⁵ cm / s. There was no difference even if the front and back were reversed. The change in the amount of infiltration due to the precipitation change with a 3% gradient (increased from 10 mm / hour to 40 mm / hour) was 3.8 times.

Example 4
The capping sheet of Example 1 was attached and bonded to the overlapped portion of the first fiber sheet with a modified asphalt-based tape (Tajima Roofing Co., Ltd., Gumrich 18, tape width 18 cm). It was left at room temperature for 1 week under a load equivalent to 50 cm covering soil. After unloading and measuring the joint strength at the joint, it was 540 N / 5 cm, and it was found that there was no problem in practical use. Even if the joint was left with a water pressure of 5 cm in the same manner as that for measuring the nail hole sealability, no leaking occurred.

  The capping sheet for waste covering according to the present invention can provide a capping sheet with a small fluctuation in the amount of intrusion even if the laying conditions such as rainfall and slope gradient fluctuate. Although it is a product, it is possible to provide a capping sheet that is easy to obtain a water permeability suitable for a laying place, which contributes to the industry.

However, if the slopes gradient is changed, there is a possibility of variation in the entering water. The present invention, by changing the table back, and to provide an easy-capping sheet to obtain a suitable water permeability in its place.

According to the present invention, by changing the table back, while the same product, it is possible to provide an easy-capping sheet to obtain a suitable water permeability laying location.

Claims (8)

A water-permeable capping sheet for waste covering having a laminated structure of at least two layers, comprising a first fiber sheet and a porous sheet,
The capping sheet has a basis weight of 80 to 1200 g / m ² , and the water permeability coefficients of both sides of the capping sheet measured by JIS A1218 (1998) 5 method (constant water level permeability test) are both 1 × 10 ⁻⁷ to 1 A waste-covering capping sheet that is × 10 ⁻³ cm / s and has a value of 50% or more greater on the surface of the capping sheet having a higher water permeability than the surface of the lower surface.   The water-permeable capping sheet for waste covering according to claim 1, wherein the second fiber sheet is laminated on the opposite surface side of the first fiber sheet. The waste coating capping sheet according to claim 1 or 2, wherein the porous sheet is a porous sheet in which 0.1 to 14 holes having a diameter of 1.0 mm or less are provided per 1 cm ² .   The first fiber sheet is a thermocompression-bonded long-fiber nonwoven fabric made of at least one resin selected from the group consisting of polyolefin resins, polyester resins, and polyamide resins. The capping sheet for waste covering as described. The first fiber sheet is a light blocking ratio of 90% or more, the waste coating capping sheet according to claim 1 having a basis weight is 70~500g / ^{m 2.} The second fiber sheet is a nonwoven fabric produced by a needle punch method having a thickness of 0.2 to 10.0 mm, a basis weight of 50 to 1000 g / m ² , and a penetration resistance of 200 N or more. The capping sheet for waste covering described in 1.   The disposal according to any one of claims 1 to 6, wherein when laid on a slope of 3% to 5%, even if the rainfall increases from 10 mm / hour to 40 mm / hour, the infiltration amount does not increase more than three times. Capping sheet for covering objects.   A joining method in which the capping sheet according to any one of claims 1 to 7 is joined with a tape made of modified asphalt, followed by covering with a soil of 30 to 100 cm.