JP4011666B2 - Laminated impermeable sheet and method for producing the same - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a laminated waterproof sheet for laying on the inner surface of a waste disposal pond to prevent leakage from the disposal pond.
[0002]
[Prior art]
In a waste disposal site, rainwater that has penetrated the waste and waste liquid contained in the waste itself are prevented from leaking from the treatment site and contaminating groundwater and rivers. For example, a vinyl chloride sheet or a rubber sheet is spread on the inner surface of the dumping pond, and the surface is sanded to protect the soft water-impermeable sheet, or a nonwoven fabric is spread to form a waste disposal pond. Furthermore, for the sake of completeness, there are some in which a water-swellable fiber layer is formed between the water-impervious layers with two water-impervious layers. Japanese Utility Model Publication No. 4-40903 discloses a waterproof layer in which a water-impermeable sheet is laminated on the upper and lower surfaces of a three-dimensional entangled network structure in which a filament having a large fineness is formed on a plane having a porosity of 85% or more and a thickness of 4 to 9 mm. Is marked.
[0003]
[Problems to be solved by the invention]
However, when such a surface is made of only a soft impervious sheet, if there are sharp protrusions in the waste, the impervious sheet breaks due to piercing, etc., and contaminated water leaks from the damaged part. May contaminate the surrounding environment. Thus, for example, a method is considered in which a two-layer impermeable sheet is stretched, and even if the first impermeable sheet is torn, the second impermeable sheet prevents leakage of sewage. Depending on the penetration pressure, the second layer of the water-impermeable sheet may be broken.
[0004]
Therefore, a water-swellable fiber layer is further laminated between the upper water-impervious sheet and the lower water-impervious sheet to form a triple waterproof layer, and the water-impermeable sheet is formed by the penetration pressure of the protrusions. When water is damaged, the water-swellable fiber layer absorbs and swells to block the damaged surface of the water-impermeable sheet and prevent leakage of contaminated water, but there are various types of contaminated water such as acids, alkalis, solvent systems, and salts. Since various types are included and the water-swellable fibers do not swell sufficiently, a water-impermeable layer is not formed, and water may permeate and sewage may leak and contaminate the surrounding environment.
[0005]
The present invention solves the above-mentioned problems and inconveniences in a conventional laminated water-impervious sheet, and provides a laminated water-impervious sheet that can prevent leakage of sewage from the damaged portion even if the impermeable sheet is damaged. To do.
[0006]
[Means for Solving the Problems]
In the present invention, a nonwoven fabric covering material with low water permeability is arranged on both outer sides of the water impermeable sheet, and a water shielding layer is formed between the two water impermeable sheets and a three-dimensional network mat between the covering materials, The above problem has been solved by filling a three-dimensional network with a water-swelling water-stopping agent.
[0007]
That is, the present invention is not effective on both surfaces of a three-dimensional network mat having a porosity of 70 to 99% in which a large number of thermoplastic synthetic continuous polymer filaments having a diameter of 0.5 to 2 mm are formed in irregular loops. A laminated water-impervious sheet formed by laminating a water-permeable sheet, further laminating a non-woven fabric covering material on both outer surfaces of the water-impermeable sheet, and filling a fluid waterproofing agent inside the three-dimensional network mat. .
[0008]
Because of such a configuration, when the water-impermeable sheet is damaged by protrusions or the like, even if the water-stopping agent in the three-dimensional mesh mat flows out of the water-impermeable sheet, a coating material with low water permeability is used. The passage of the water-stopping agent can be suppressed and the waterproofness can be maintained.
[0009]
The covering material on the front and back is a water-permeable nonwoven fabric of the same quality having a water permeability coefficient (cm / sec) of 2 × 10 ^{−4 to} 9 × 10 ⁻⁴ , or an outer layer having a coarse fiber density and an inner layer having a dense fiber density (Layer on the side in contact with the water-impermeable sheet), each having a water permeability coefficient (cm / sec) of 1 × 10 ^{−2 to} 5 × 10 ^{−3 for} the outer layer and 2 × 10 ^{−4 to} 9 for the inner layer A water-permeable nonwoven fabric of × 10 ⁻⁴ is preferable.
The water permeability is measured according to JIS-A-1218 method.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The non-woven fabric used as the outer layer having a coarse fiber density is a synthetic fiber such as polyester, polypropylene, polyethylene, polyamide, etc., having a fineness of 2 to 15 denier, a fiber length of 50 to 90 mm, and a basis weight of 200 to 1000 g / m ² . It can be obtained by needle punching the web.
[0011]
In addition, the nonwoven fabric used as the inner layer having a dense fiber density is composed of two types of polymers selected from thermoplastic synthetic polymers such as polyester, polypropylene, polyethylene, polyamide, and ethylene vinyl acetate in the fiber cross section as shown in FIG. A composite fiber having a structure of 2 to 5 deniers having a structure arranged in a non-woven fabric can be obtained by subjecting this to a web by a normal method to high-pressure water treatment to divide the composite fiber and entangle the fibers with each other. it can.
[0012]
When the water permeability coefficient (cm / sec) of the covering material in contact with the waterproofing material layer is larger than 2 × 10 ⁻⁴ , the waterproofing agent ejected from the inside when the waterproofing agent layer breaks passes through the covering material and decreases the water-stopping property. To do. When it is smaller than 9 × 10 ⁻⁴ , the blocking property of the water-stopping agent is improved, but the production cost of the nonwoven fabric is increased.
[0013]
In addition, the nonwoven fabric having a water permeability coefficient (cm / sec) of 1 × 10 ^{−2 to} 5 × 10 ⁻³ is a covering material (water permeability coefficient 2 × 10 ^{−4 to} 9 ×) that is in contact with the waterproof layer that is the inner layer. 10 ⁻⁴ ). When the water permeability coefficient (cm / sec) is greater than 1 × 10 ⁻² , the impact mitigating effect of the waste is reduced. If it is smaller than 5 × 10 ⁻³ , the impact mitigating effect is improved, but the production cost is increased.
[0014]
The water-impermeable sheet is a film-like sheet material such as rubber, polyethylene, polypropylene, ethylene vinyl acetate, and the thickness thereof can be 0.4 to 3.0 mm. If it is 0.4 mm or less, the impact strength due to the projection of the waste is insufficient, which is not preferable. If it is 3 mm or more, the impact strength is improved, but the cost is increased, and it is preferably 1.0 to 2.0 mm.
[0015]
The three-dimensional network mat arranged between the upper and lower two water-impermeable sheets is a bulky three-dimensional network with a large porosity formed by a large number of synthetic polymer continuous filaments having a diameter of 0.5 to 2 mm. The body mat can be a single melt or two or more composite melts of thermoplastic synthetic polymers such as polypropylene, polyethylene, polyamide, polyester, etc., but in view of production cost, polypropylene with a relatively low melting point Polyethylene is preferred. Such a three-dimensional network mat can be manufactured by a known method, for example, a method described in Japanese Patent Publication No. 63-53332.
[0016]
Specifically, this three-dimensional network mat is a mountain that is irregularly bent in the horizontal direction and the thickness direction while many of the continuous filaments of the synthetic polymer having a diameter of 0.5 to 2 mm intersect each other. It extends from one side to the other while forming a part and a valley part, and has a structure in which the crossing points are bonded to each other. The thickness is 3 to 100 mm, preferably 5 to 20 mm, and a high porosity of about 70 to 99%. It is desirable to have compressive strength against earth pressure while having it.
[0017]
For example, a solid reticulated mat with a thickness of 12.5 mm and an apparent porosity of 95% is a continuous filament made of polypropylene having a diameter of 1.05 mm, and the distortion rate is 26% when a compressive load of 5 ton / m ² is applied. In the case of 10 tons / m ² , it was 48%, and in the case of 40 tons / m ² , it was 78%.
[0018]
Moreover, if the porosity is less than 70%, the entanglement of the synthetic polymer continuous filaments is too large and it becomes difficult to inject the water-stopping agent, and if it exceeds 99%, the compressive strength against the earth pressure decreases and the injection amount of the water-stopping agent increases. It decreases and the water stop function declines.
[0019]
As the water-stopping agent to be filled in the reticulated mat, a natural product of clay minerals such as bentonite belonging to the genus montrilite, padelite, non-tetronite, sabonite, hectorite, attalgite of holmite, sepiolite, or a mixture of 5 to 50 Prepare a weight% aqueous solution and apply water pressure. If the waterstop agent is less than 5%, the injection work is easy to perform, but it takes a long time to exhibit the waterstop effect. If it is 50% or more, the viscosity of the water-stopper solution is too high and the injection work becomes difficult.
[0020]
The laminated water-impervious sheet of the present invention can be installed as follows.
First, a non-woven fabric covering material is unfolded and stretched on the surface of the waste disposal pond that has been pressed, and an impermeable sheet is unfolded and stretched on the upper surface, and a three-dimensional mesh mat is unfolded and stretched on the upper surface of the impermeable sheet. Further, an impervious sheet and a covering material are developed and stretched in this order on the upper surface. At this time, if the covering material, the water-impermeable sheet, and the three-dimensional network mat are spread and stretched while being partially welded with hot air, the work is easy to do.
[0021]
The waterproofing agent is injected into the three-dimensional network mat of the waterproof layer by installing a waterproofing agent head tank at the top of the shoulder of the waste disposal pond, filling the waterproofing agent, and injecting with a water pressure difference. Can be filled.
[0022]
【Example】
Hereinafter, the present invention will be described by way of examples. FIG. 2 is a sectional view showing the structure of the laminated water-impervious sheet (6) of the present invention.
A water-impermeable sheet (2) is laminated on both sides of the three-dimensional network mat (1), and a non-woven fabric to be a coating material (3) is further laminated on both outer sides thereof. The water-repellent agent (4) is filled into the interior of the three-dimensional network mat. At this time, the covering material is preferably composed of two layers of an outer layer portion (3a) made of a non-woven fabric having a coarse fiber density and an inner layer portion (3b) made of a dense non-woven fabric (one in contact with the water-impermeable sheet).
[0023]
Each member which comprises the said laminated water-impervious sheet | seat (6) of this invention can be manufactured as follows.
(Three-dimensional mesh mat)
The three-dimensional network mat (1) is a continuous filament made of polypropylene having a diameter of 1.05 mm as shown in the perspective view of FIG. 3 by a known method (Japanese Patent Publication No. 63-53332), and has a basis weight of 600 g / m ² and a thickness. 12.5 mm with an apparent porosity of 95% was manufactured and used.
[0024]
(Coating material)
The outer layer (3a), which is a nonwoven fabric with a coarse fiber density, is 70% polyester fiber having a fineness of 8 denier and a fiber length of 51 mm, and 30% polyester fiber having a fineness of 3 denier and a fiber length of 51 mm. A non-woven fabric having a basis weight of 500 g / m ² and an apparent thickness of 6.5 mm obtained by superimposing card webs made from a mixture of cotton and needle punching was used. This nonwoven fabric had a fiber density of 0.08 g / cm ³ and a water permeability of 1.95 × 10 ⁻³ cm / sec.
[0025]
Further, the inner layer portion (3b), which is a non-woven fabric having a high fiber density, has a 16-section type composite fiber DF-5 (trade name) having a fiber cross section as shown in FIG. 1 composed of a polyester component (A) and a polyamide component (B). , Manufactured by Daiwa Boseki Co., Ltd., fineness 3 denier, fiber length 51 mm), and the card was processed into a card web by a card machine, and then this web was treated with a high-pressure columnar water flow (discharge water pressure 120 kg / cm ² , speed 3 m / min). The fiber was divided into each component to make the above two components (A) and (B) into ultrafine fibers of 0.19 denier and entangled between the fibers, and the basis weight was 100 g / m ² , the apparent thickness was 0. A 6 mm non-woven fabric was used. The nonwoven fabric had a fiber density of 0.17 g / cm ³ and a water permeability of 4.1 × 10 ⁻⁴ cm / sec. Moreover, the division ratio of the fibers constituting the nonwoven fabric was 90%.
[0026]
(Impermeable sheet)
As the water-impermeable sheet (2), ethylene, propylene vulcanized rubber having a thickness of 1.5 mm, a tensile strength of 250 kg / cm ² and an elongation of 650% was used.
[0027]
(Water stop agent)
The water-swellable water-stopping agent filled in the voids of the three-dimensional network mat (5) was prepared by dispersing and swelling bentonite in water to 15% by weight. In this case, a bentonite dispersant may be used in combination.
[0028]
Example 1
The above members are laid in the waste disposal pond as follows. As shown in the cross-sectional view of FIG. 4, the ground (12) is excavated and the pond (10) is created and constructed, and the surface is crushed to form a waste disposal pond. First, the covering material outer layer portion (3a) is spread and laid, and the covering material inner layer portion (3b) is spread and laid thereon. The adjacent interior parts are overlapped by about 30 cm. Next, the impermeable sheet (2) is spread and laid on the interior portion of the covering material, and the three-dimensional mesh mat (1) is spread and laid thereon.
[0029]
Next, the water-impermeable sheet (2), the covering material interior part (3b), and the covering material outer layer part (3a) are respectively laid on the three-dimensional network mat (1) in the reverse order.
The seam of the three-dimensional mesh mat is shaped as schematically shown in the cross-sectional view of FIG. 5, and the upper and lower impermeable sheets (2) are made by connecting the upper and lower connecting plates (5) made of the same material as the impermeable sheet (2). Hot air is blown onto (2) to weld the upper and lower water-impermeable sheets (2) and (2) and the upper and lower connecting plates (5) to form the three-dimensional network mat (1) of the water-impermeable sheets (2) and (2). One unit is formed in the form of being wrapped inside the bag. One bag is suitably about 2m x 5m.
Moreover, the welding surface of the adjacent water-impermeable sheet is overlapped by about 20 to 30 cm, and the whole area is welded between the overlapping surfaces.
[0030]
Next, an approximately 50 cm-thick soil is covered on the upper surface of the laminated water-impervious sheet.
Next, the water-stopping agent storage tank (11) provided at a high level in the waste disposal pond is connected to each unit with a pipe, and the water-stopping agent (4) in the water-stopping agent storage tank (11) is connected. ) Flows into the space of the three-dimensional mesh mat (1) by opening the on-off valve, and is filled, thereby completing the waste disposal pond by the laminated water-impervious sheet (6) of the present invention.
[0031]
The case where the nonwoven fabric of the dressing in the embodiment of the laminated water shield sheet of the present invention was used only the inner layer portion (hydraulic conductivity 4.1 × 10 ^-4) and (b), outer layer (permeability coefficient 1.95 × 10 ^{- 3} ) When each was used only (b), each water pressure resistance (kg / cm ² ) was tested.
The evaluation method was carried out by enclosing a bentonite 20% solution adjusted with a fine powder of 250 mesh according to the water resistance test method of JISL-1079, and using a necessary auxiliary tool. As a result, the water pressure resistance (kg / cm ² ) is (b) 2 or more (b) 0.1
Met.
[0032]
【The invention's effect】
The laminated water-impervious sheet of the present invention has a nonwoven fabric covering material disposed on both sides, and a waterproof material layer interposed between the covering materials, and the waterproof material layer has two upper and lower water-impermeable sheets disposed thereon. Furthermore, since the three-dimensional network between the two water-impermeable sheets is filled with a water-swelling water-stopping agent, the water-impermeable sheet is protected from the projections in the waste by the covering material. In addition, even if one of the upper and lower impervious sheets is damaged, the other impervious sheet maintains its waterproof function, preventing contaminated water from leaking from the waste disposal pond and flowing into the ground. To do. Further, when the water-impermeable sheet is torn, the water-swelling water-stopping agent disposed between the water-impermeable sheets flows out from the damaged portion to the surface of the covering material, the water-stopping agent is filtered, It is possible to prevent the contaminated water in the waste disposal basin from flowing out into the ground by closing the gap between the fibers of the covering material.
[0033]
In addition, the water-swelling water storage tank for the water-swelling water-stopping agent should be placed at a position higher than the standard level of the waste disposal pond, so that the impervious sheet in the storage tank and the waste disposal pond is connected by piping. If connected, the pressure in the waterproofing agent between the impervious sheets is higher than the pressure in the waste disposal pond, so the contaminated water in the waste disposal ponds will remain between the impervious sheets. There is no risk of inflow. Further, it is possible to smoothly replenish the water-impermeable sheet that is damaged and the water-stopping agent is transferred from the damaged portion to the surface of the covering material.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a structure of a split type composite fiber used for a nonwoven fabric having a dense fiber density of a covering material.
FIG. 2 is a cross-sectional view of a laminated water shielding sheet used in an example of the present invention.
FIG. 3 is a perspective view of a three-dimensional network mat.
FIG. 4 is a cross-sectional view showing the structure of a waste disposal site using the laminated waterproof sheet of the present invention.
FIG. 5 is a cross-sectional view showing the structure of the joint portion of the laminated water-impervious sheet of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Three-dimensional network mat 2 Impervious sheet 3 Coating | coated material 3a Coating | coated material outer layer part 3b Coating | coated material interior part 4 Water-stopping agent 5 Vertical connection board 6 Laminated water-proof sheet 10 Pond 11

Claims (6)

  A plurality of thermoplastic synthetic continuous polymer filaments having a diameter of 0.5 to 2 mm are laminated on both surfaces of a three-dimensional network mat having a porosity of 70 to 99% formed by forming irregular loops. Furthermore, a laminated water-impervious sheet obtained by laminating a nonwoven fabric covering material on both outer surfaces of the water-impermeable sheet, and filling the three-dimensional network mat with a fluid waterproofing agent. The laminated water-impervious sheet according to claim 1, wherein the covering material is a water-permeable nonwoven fabric having a water permeability coefficient (cm / sec) of 2 × 10 ^{−4 to} 9 × 10 ⁻⁴ . The covering material is composed of two layers, an outer layer having a coarse fiber density and an inner layer having a dense fiber density (layer on the side in contact with the water-impermeable sheet), and each of the water permeability coefficients (cm / sec) is 1 × 10. The laminated water-impervious sheet according to claim 1, which is a water-permeable nonwoven fabric of ^{−2 to} 5 × 10 ⁻³ and an inner layer of 2 × 10 ^{−4 to} 9 × 10 ⁻⁴ . The covering material consists of two layers: an outer layer with a coarse fiber density and an inner layer with a dense fiber density (layer on the side in contact with the water-impermeable sheet). laminated water shield sheet according to claim 1, wherein the 0.18 to 0.7 denier microfine fibers microfine is divided is 90 wt% or more including hydroentangled nonwoven by the process. The water-stopping agent is a 5-50 % by weight aqueous solution of one or a mixture of two or more selected from the group consisting of bentonite belonging to the genus Monrilonite, padelite, non-tetronite, sabonite, hectorite, attavalgite belonging to the genus holmite, and sepiolite. The laminated water-impervious sheet according to claim 1.   It is a manufacturing method of the laminated water-impervious sheet according to any one of claims 1 to 5, wherein a large number of thermoplastic synthetic continuous polymer filaments having a diameter of 0.5 to 2 mm are formed in irregular loops. A water-impermeable sheet is laminated on both surfaces of a three-dimensional network mat having a porosity of 70 to 99%, and a non-woven coating material is laminated on both outer surfaces of the water-impermeable sheet. A method for producing a laminated waterproof sheet, which comprises injecting a fluid waterproofing agent in a waterproofing agent storage tank.

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