JPH0966575A - Impervious structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to perform sufficient self-restoring function even if a sheet is perforated without moving gel by a load by sandwiching the foam of closed cell structure made of synthetic resin, natural rubber or synthetic rubber at the intermediate between the sheets of synthetic resin or rubber of upper and lower layers. SOLUTION: Foam 93 of a closed cell structure made of natural rubber or synthetic rubber is sandwiched at the intermediate between the sheets 91 and 92 of synthetic resin or rubber of upper and lower layers. Accordingly, gel is not moved by a load, and even if the sheet is perforated due to a protrusion, it can be self-restored by the foam 93 to make it possible to prevent the water leakage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-impervious structure used for waterproofing a waste disposal site, a reservoir, an artificial pond, a building or the like.

[0002]

2. Description of the Related Art In a waste treatment plant, as shown in FIG. 4, in order to prevent underground pollution due to leachate generated from the waste 70, a synthetic resin-based or synthetic rubber-based waterproof sheet on the ground surface 60. The method of laying 80 is adopted.
However, these impermeable sheets may be damaged due to any of the protrusions in the waste, or the protrusions such as gravel exposed on the foundation ground of the impermeable sheet. There is a problem of polluting the surrounding environment.

As a measure against such a problem, a means for inserting a highly water-absorbent resin between the upper and lower two layers of the water-blocking sheet and swelling by water absorption and self-repairing even if the water-blocking sheet is damaged. (JP-A-6-171005, JP-A-6-166145, JP-B-5-1879,
Japanese Patent Publication No. 6-5886, etc.), but a single piece of water-absorbent resin is inserted between the sheets, and due to the load of waste (landfill) or the load of the work machine for moving waste, There is a problem that it is easy to move between the water-impermeable sheets, the water-impermeable function is deteriorated, and the resin (hereinafter referred to as “gel”) that has absorbed water from the damaged holes is washed away, and the sufficient effect cannot be exhibited.

[0004]

The problem to be solved by the invention is to insert a super absorbent resin between the upper and lower two layers of the water-impermeable sheet, and when the water-impermeable sheet is damaged, the resin absorbs water and swells to absorb itself. In the conventional water-blocking sheet that is designed to have a restoration function,
This is because under various loads, the superabsorbent resin moves between the water-impermeable sheets, the water-impermeable function is deteriorated, and further, the gel is washed away from the damaged holes, so that the sufficient effect cannot be exhibited. The present invention is to solve the above problems, to provide a water-impervious structure that does not have gel migration due to load, and has sufficient self-repairing function due to swelling of closed cells even if holes are formed in the upper and lower sheets. is there.

[0005]

Basically, the present invention is
The water-impervious structure is characterized in that a foam having a closed cell structure made of synthetic resin, natural rubber, or synthetic rubber is sandwiched between two upper and lower synthetic resin-based or synthetic rubber-based sheets.

The above-mentioned foam is water-swellable, and the water-absorbent polymer is uniformly dispersed in the foam, or the material of the above-mentioned sheet is excellent in water impermeability, Soft synthetic resin or synthetic rubber type, which has excellent workability and is easy to work with, specifically, polyvinyl chloride resin, polyethylene resin, polypropylene resin, polyurethane resin, ethylene propylene rubber, chloroprene rubber , Or polyurethane rubber is preferable.

Furthermore, in addition to the above-mentioned constitution, the material of the foam having a closed cell structure constituting the intermediate layer has a cushioning property,
Polyvinyl chloride resin, polyethylene resin, polyurethane resin, silicone resin, natural rubber, isoprene rubber, butadiene rubber, which has water-blocking properties and conformability to the substrate, 1,
It is preferably any one of 2-polybutadiene, styrene butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, ethylene propylene rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, silicone rubber, fluororubber and urethane rubber.

Further, the types of the water-absorbent polymers are polyacrylic acid type, polysulfonic acid type, acrylic acid graft type, quaternary ammonium salt type, polyvinyl alcohol type, polyacrylamide type, which are excellent in absorbability and expandability. system,
It is preferably one of polyoxyethylene type.

Even if a breakage occurs due to a projection, these sheets have a high resistance to tearing, so that the degree of breakage can be minimized, and the effect of preventing water leakage by the intermediate layer can be further exerted.

The sheet thickness of the upper and lower layers is 0.5 mm to 5.0 mm, preferably 1.0 mm to 2.0 mm. If the thickness of the layer is less than 0.5 mm, the resistance to tearing is not sufficient and it is 5.0 mm.
If it exceeds, the cost becomes high and the weight becomes large, so that the workability at the time of constructing the seat deteriorates.

The foam has a cell structure having a closed cell ratio of 80% or more as measured by a Beckman air-comparison hydrometer according to ASTM D2586, and the expansion ratio is 1.5 to 8 times, preferably 2 to 4 times. Double is desirable. If it is less than 1.5 times, the cushioning property is not sufficient, and if it exceeds 8 times, the tensile strength decreases.

The foam has a thickness of 2 mm or more, preferably 2 mm.
mm to 20mm is good. If it is less than 2 mm, the cushioning property is impaired and the cushioning effect is reduced. If it exceeds 20 mm, the cost becomes higher and the weight becomes heavier, so that the workability at the time of sheet construction is deteriorated.

The water-absorbent polymer which is uniformly dispersed in the foam is a polyacrylate type, polysulfonate type, acrylate graft type, quaternary ammonium salt type, polyvinyl alcohol type, which has excellent absorbency and expandability. It is preferable to use polyacrylamide type and polyoxyethylene type.

A sponge having a cell structure with a closed cell rate of 80% or more has a low gas permeability and becomes a cell in which the gas in the cell does not easily escape, and has excellent cushioning properties, and its cushioning effect prevents the sheet from being damaged by protrusions or the like. It can be prevented. Further, due to its rubber elasticity, when the protrusion is stuck, the protrusion is wrapped and the repulsive force closes the hole portion.

Further, since the individual bubble walls are present independently, the passage of water is blocked even if water enters due to breakage of the sheet or the like, so that water blocking effect is exhibited. When the protrusion penetrates the foam and the cell is partially connected, the strain in the surrounding independent cell wall is released, and the self-healing property of the hole portion is exhibited. In addition, due to the elasticity and elasticity of the foam, it can follow ground subsidence. Furthermore, by uniformly dispersing the water-absorbing polymer in the foam having a closed cell structure, the foam exhibits a self-repairing function due to the water-swelling action.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG.
A foamed body 93 having a closed cell structure made of synthetic resin, natural rubber, or synthetic rubber is sandwiched between sheets of synthetic resin-based or synthetic rubber-based sheets 91 and 92. 6
0 is the ground surface and 70 is waste. The present invention is not limited to the following as long as the gist thereof is not exceeded.

[0017]

【Example】

(Measuring method of water leakage amount) Water-blocking structure 50 according to FIGS. 1 and 2.
Explaining the test equipment for evaluating the amount of water leakage in
Is a pressurized container, and the upper and lower parts 1 horizontally divided in the middle
The water-impervious structure 50, which is the sample, is sandwiched by the flanges provided at the upper and lower ends of 2 and 13, respectively. Reference numeral 14 denotes a horizontal shelf portion provided with a plurality of vertical through holes 15, which is provided in the lower portion 13 of the pressure vessel 11 directly below the water blocking structure 50. 16 is the opening degree laid on the upper surface of the shelf portion 14.
Two screens of about 10 mesh, 17 is a conical test projection (details described later) standing upright in the center of the screen 16, and 18 and 19 are upper and lower parts 12, 13 of the pressure vessel 11.
Water supply pipe and water withdrawal pipe, which are attached to the upper and lower surfaces, respectively
Is a pump for feeding water to the upper portion 12 of the pressurizing container 11 to pressurize, 30 is a pressure gauge, and 40 is a graduated cylinder for measuring the amount of water leakage.

The conical test protrusion 17 will be described. The height C = 31 mm, the apex angle B = 30 °, and the apex is formed into a spherical surface having a radius R = 1 mm. The distance between the lower surfaces of the water-impervious structures 50 is D = 40 mm when no water pressure is applied.

Using the above test equipment, a water pressure of 10 kgf / cm ² -G was applied to the water-impervious structure 50 of the test piece, and the amount of water leakage was measured for 24 hours thereafter. Separately, a water pressure of 3 kgf / cm ² -G was applied to the test piece in a 1-minute cycle, and the number of times until breakage was measured. The results are shown in Table 1 and FIG.

(Example) Explaining the test results,
Geoplane sheet (EPDM type thickness 1.5 mm) manufactured by Mitsubishi Kagaku MKV Co., Ltd. as the upper and lower layers, and closed-cell water-expandable sponge sheet manufactured by Nishikawa Rubber Industries Co., Ltd. as the intermediate layer (using chloroprene rubber as the base rubber, vulcanizing agent, filling) Mixing agent, foaming agent, water-absorbent polymer and kneading
Foam-molded under vulcanization conditions of 0 ° C 15 minutes + 165 ° C 15 minutes, a sheet having a specific gravity of 0.4, a thickness of 3 mm, and a closed cell rate of 100%) was subjected to the test. The water-absorbent polymer used was a mixture of polyacrylate salt of 60 parts by weight.

Comparative Example 1 A geoplane sheet (thickness: 3 mm) manufactured by Mitsubishi Kagaku MKV Co., Ltd. was used as a single unit for the test.

(Comparative Example 2) As the upper and lower layers, a geoprene sheet manufactured by Mitsubishi Kagaku MKV Co., Ltd. (EPDM system thickness 1.
5mm), chloroprene rubber (non-foamed) as an intermediate layer,
A sheet having a thickness of 3 mm to which the same amount of the water swelling agent as in the example was added was prepared and subjected to the test.

(Test result) It is clear from Table 1 and FIG.
Thus, the single sheet of Comparative Example 1 is 10 kgf / cm² -G
When water pressure is applied, the amount of water leakage after 1 hour is 180cc, 24 hours
The amount of water leakage afterwards is as large as 350cc and 3kgf / cm in 1 minute cycle.²
When the water pressure of -G was repeatedly applied, it was broken 10 times. Ma
Also, in the structure of Comparative Example 2, 10 kgf / cm²-Add G water pressure
If so, the amount of leakage after 1 hour is 70cc, and the amount of leakage after 24 hours
Is 150cc, which is less than the single sheet of Comparative Example 1, but sufficient.
Not a minute, 3kgf / cm in 1 minute cycle²-G water pressure
When added repeatedly, it broke after 15 times. In addition, Comparative Example 1
In Comparative Example 2, there is a tendency that the amount of leaked water increases until 24 hours,
The water leakage prevention effect was insufficient.

On the other hand, in the example of the present invention, the leakage amount after 1 hour was 20cc and the leakage amount after 2 hours was 25cc. Was enough. When repeatedly pressed, it did not break even after 20 times. That is, the sheet applied to the present invention is less likely to be damaged, and even if breakage due to a protrusion occurs, since the resistance strength against tearing is large, the damage degree is minimized, and the water leakage prevention effect by the intermediate layer is provided. It is judged that he was able to exert his.

[0025]

Since the present invention is configured as described above,
Even if the sheet is perforated due to protrusions or the like, the effect of self-repairing the sheet by the intermediate layer and preventing water leakage is remarkable.

[Brief description of drawings]

FIG. 1 is a sectional view showing a test apparatus for water leakage evaluation.

FIG. 2 is a front view showing the shape of a test protrusion used in the test apparatus.

FIG. 3 is a graph showing the relationship between the elapsed time and the amount of water leakage in Examples, Comparative Examples 1 and 2.

FIG. 4 is a view showing a state of using a conventional water-blocking sheet.

FIG. 5 is a state of use of the water barrier sheet of the present invention.

[Explanation of symbols]

11 Pressurized Container 12 Upper Part 13 Lower Part 14 Shelf 15 Through Hole 16 Screen 17 Test Protrusion 18 Water Supply Pipe 19 Water Extraction Pipe 20 Pump 30 Pressure Gauge 40 Measuring Cylinder 50 Water Impermeable Structure 60 Ground Surface 70 Waste 80 Water-impermeable sheet 91 Water-impermeable upper sheet 92 Water-impermeable lower sheet 93 Water-expandable closed-cell foam

[Table 1]

Front page continuation (72) Inventor Tatsuro Toyoda 2-8, Misonomachi, Nishi-ku, Hiroshima City Nishikawa Rubber Industrial Co., Ltd. (72) Seiji Okaya 2-2 Misonomachi, Nishi-ku, Hiroshima City Nishikawa Rubber Industrial Stock In the company

Claims (6)

[Claims] 1. A water-impervious structure comprising a synthetic resin-based or synthetic rubber-based sheet of upper and lower layers, and a closed-cell foam made of synthetic resin, natural rubber, or synthetic rubber sandwiched between the sheets. . 2. The water-impervious structure according to claim 1, wherein the foam has a water-swelling property. 3. The water-blocking structure according to claim 2, wherein the water-absorbent polymer is uniformly dispersed in the foam. 4. The sheet material is polyvinyl chloride resin,
It is any one of polyethylene resin, polypropylene resin, polyurethane resin, ethylene propylene rubber, and chloroprene rubber, The water-impervious structure according to claim 1. 5. The material of the foam is polyvinyl chloride resin,
Polyethylene resin, polyurethane resin, silicone resin, natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, ethylene propylene rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, silicone rubber, fluororubber Or the urethane rubber, the water-impervious structure according to claim 1. 6. The type of water-absorbing polymer is a polyacrylate type, a polysulfonate type, an acrylic acid graft type,
The water-impervious structure according to any one of claims 3 to 5, which is any one of a quaternary ammonium salt type, a polyvinyl alcohol type, a polyacrylamide type, and a polyoxyethylene type.