JP3357550B2 - Composite coating materials used for waste disposal sites - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a covering material for covering a landfilled waste from a waste disposal site having properties such as water-blocking and air permeability. More specifically, when the waste disposal site is closed, the landfill waste is covered from above, preventing rainwater intrusion, reducing the flow of harmful substances from the waste, and reducing the gas generated from the waste. It is intended not to be filled.

[0002]

2. Description of the Related Art Waste is generally landfilled.
A typical type of disposal site is a managed disposal site. This is to prevent landslides, prevent subsidence, and impervious work on the pre-reclaimed concavities surrounded by repellent walls and dikes, and collect and drain water that collects and drains rainwater. It is equipped with equipment for treating leaching water. In a landfill site for waste, particularly in a managed landfill site, there are problems such as generation of gas from the waste and leachate and sewage causing groundwater contamination, and solving these problems is a serious issue.

[0003] In a managed disposal site, a water-impervious sheet made of polyvinyl chloride, rubber, or high-density polyethylene having a thickness of at least 1 mm is laid on the bottom and side surfaces of the landfill. Is treated so that there is no leachate mixed with harmful substances outside. Along with this, water infiltrating from above, such as rainwater, is collected by a water-blocking sheet laid on the bottom of the landfill depression, and is drained to the outside by a facility such as a pump for treatment. In such a disposal site, after the same amount of waste is buried in the landfill, a water barrier layer is usually provided above the waste landfill layer. Providing a water barrier layer
By blocking water from the top, such as rainwater, it reduces leachable sewage, which is said to leak from the bottom and sides, as well as reducing the amount of effluent treated externally. Since it takes a very long time to reach a state where the discharged water disappears, this is a serious problem in managing the repository.

[0004] In addition, gas is usually generated from landfilled waste, and because of the presence of a water-blocking layer, this gas easily accumulates inside, and when closed, the internal pressure increases and water-blocking occurs. There is also a risk of layer destruction and explosion. The coating material used for the water barrier layer generally has a thickness of 1
A water-impermeable sheet made of polyvinyl chloride, rubber or high-density polyethylene having a diameter of at least mm is used, and there is a problem that gas easily accumulates inside. In addition, it is usual to cover soil on the covering material of these impermeable layers, and heavy equipment such as a bulldozer runs on the covered soil layers, and stones and metal on and under the impermeable sheet There is also a problem that the sheet is torn due to the debris and the water cannot be sufficiently blocked.

[0005]

As described above,
Conventional disposal sites have problems such as pollution due to leachate sewage caused by their structures and explosions due to gas that can be generated in large quantities from wastes, and require large-scale construction, complicated structures or expensive equipment. There is a need to develop means that can prevent or avoid these problems without the need. That is,
An object of the present invention is to use as a water-blocking layer that does not cause breakage due to various operations performed on a covered soil, blocks water from the outside such as rainwater, and does not collect gas generated from waste. To provide an excellent coating material.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in order to meet the above-mentioned demands, and have achieved the above object by using a composite covering material having mechanical strength, waterproofness and air permeability. And arrived at the present invention. That is, the present invention relates to a coating material for covering a landfilled waste used from a waste disposal site from above, and which is provided by a melt blow method.
A breathable waterproof layer selected from ropylene nonwoven fabric or synthetic fiber paper, and a porous three-dimensional material selected from the group consisting of a nonwoven fabric, a woven fabric, a knitted fabric, a felt film slit yarn and a net provided on at least one surface of the breathable waterproof layer A composite coating material characterized by being integrally and layered with a resin matrix layer. In a preferred embodiment of the present invention, the air-permeable waterproof layer is melt-blown.
It is a method propylene nonwoven fabric. In another preferred embodiment of the present invention, the air-permeable waterproof layer is made of synthetic fiber paper made of synthetic fiber and hot-press calendered.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The composite covering material used in the waste disposal site of the present invention comprises a waterproof layer and a porous three-dimensional resin matrix layer. The ventilation waterproof layer has a waterproof property for preventing infiltration of rainwater and a gas permeability for passing gas generated from waste. Materials having these properties include nonwoven fabrics, microporous thermoplastic films (perforated films), synthetic fiber paper, resin-impregnated fabrics, knits, and nonwoven fabrics. As non-woven fabric, paper is made using short fibers,
Synthetic fibers such as polyester, polyolefin, polyvinyl alcohol, polyamide, polyacrylonitrile, etc., rayon,
After forming a web using staples made of chemical fibers such as acetate or natural fibers such as cotton and linen, these webs are bonded by resin bonding, needle punch, stitch bond, thermal bond, or spunlace method to form a dry fabric. A nonwoven fabric or a spunbonded, nonwoven fabric spun by a spunpound, a flash, or a meltblown method, in which a filament or a film extruded by a direct spinning method of forming a fiber and forming a nonwoven fabric while stretching or flashing the web is used.

[0008] For example, using a polyester short fiber, the fibers are entangled by a high-pressure water stream and mechanically bonded to each other. The tensile strength, tear strength, and water pressure resistance are small, but they are excellent in water absorption, moisture permeability, and flexibility. Is described in JP-B-3-73665. A spun-pound nonwoven fabric that has high tensile strength, tear strength, and air permeability bonded by self-adhesion using polypropylene filaments, but has relatively low water pressure, water absorption and flexibility compared to other nonwoven fabrics 55-42175
No. Using a fiber-forming polymer polyolefin and a solvent that gasifies during spinning, the polymer solidifies while stretching and joins a continuous network of ultrafine fiber elements to form a high-strength, tough, high-water-pressure, moisture-permeable material. Flash-spun nonwoven fabric having air permeability is disclosed in Japanese Patent Publication No. 40-28.
No. 125, Japanese Patent Publication No. 41-6215, Japanese Patent Publication No. 42-19
520 and JP-B-43-21112.

Next, the hydrophobic polymer composition is melted using an ordinary melt blow spinning apparatus, a fixed amount of the molten polymer is discharged from a die, and the molten polymer is blown with a high pressure gas stream to an average fiber diameter of about 0. Spinning out as an ultrafine fiber stream of 0.1 to 5.0 μm
The fiber stream is conveyed, and the fiber stream is accumulated in a collector to form a melt-blown ultrafine fiber nonwoven fabric. The weight of this non-woven fabric is 30 to 500 g / m ² when used as a single non-woven fabric, and 15 when it is used by lamination with another highly permeable sheet.
And meltblown microfibrous non-woven fabric of to 200 g / m ^2. The obtained nonwoven fabric is calendered on at least one side, subjected to treatment such as pressing or hot pressing, densified or partially fused, and if necessary, a treatment agent for increasing water resistance is applied, and a high water-resistant nonwoven fabric sheet is applied. And Examples of the resin impregnated fibrous body include JP-B-60-4795.
Japanese Patent Publication No. 5-85672 discloses a breathable waterproof nonwoven fabric obtained by coating a nonwoven fabric with a thermoplastic resin containing a filler, calendering the film, and forming a calender. It has been disclosed.

[0010] The microporous thermoplastic film used in the present invention is formed into a film by adding a fine powder such as calcium carbonate when forming the film from a thermoplastic resin. Many of them,
It is a film that has moisture permeability and air permeability, and also has waterproofness. When forming this microporous thermoplastic film, the microporous thermoplastic film used in the present invention,
Optimally, the moisture permeability is 2000 to 10000 g / m ² · 24 Hr, the water pressure resistance is 2000 mm or more, and the air permeability is 50 to 400 seconds or less. For example, polyolefin resins such as polyethylene and polypropylene, polystyrene resins, polyamide resins, polyester resins, and polyacrylate resins can be used as the thermoplastic resin.

As a method for providing fine pores in a thermoplastic resin film, a method of simultaneously adding various fine powders such as calcium carbonate at the time of forming a thermoplastic resin, a method of adding an incompatible resin, and the like. And a method of adding a plasticizer, and it is possible to produce an air-permeable film having fine pores inside by stretching the film after film formation. Alternatively, a breathable waterproofing film comprising a specific proportion of a thermoplastic resin and a filler described in Japanese Patent Publication No. 5-75010 and having fine pores formed by calendering may be used.

The synthetic fiber paper used in the present invention is composed of ultrafine short fibers having a diameter of 0.1 to 5.0 mm or pulp-like material and synthetic fibers, and is manufactured by hot-press calendering after papermaking. It is a thing. In addition, a water-repellent agent or a resin agent for improving waterproofness, an ultraviolet absorber and a light stabilizer for improving weather resistance, an antioxidant for improving durability, and a surface protective agent for the sheet material constituting the ventilation waterproof layer. Such a chemical or resin may be applied or contained in a component constituting the sheet.

[0013] The porous three-dimensional resin matrix layer used in the present invention is provided to prevent the waterproof waterproof layer from breaking. In other words, the stones contained in the earth covering or the stones and metal scraps contained in the waste landfill layer come into contact with each other and are broken by being strongly pressed. In particular, when heavy equipment runs on the earth covering, the sharp stones can be ventilated and waterproof. The purpose is to suppress the destruction of the layer. The porous three-dimensional resin matrix layer is composed of at least one selected from a nonwoven fabric, a woven fabric, a knitted fabric, a felt, a film slit yarn, a net, and the like. In order to suppress the destruction of the ventilation waterproof layer by sharp stones, etc., a nonwoven fabric, woven fabric, knitted fabric,
Felt is preferred, and to prevent small tears,
It is preferred that there be a porous three-dimensional resin matrix layer on both sides of the breathable waterproof layer.

The composite coating material obtained by joining the air-permeable waterproof layer and the porous three-dimensional resin matrix layer of the present invention can be produced by a known method. General methods include sewing, dot bonding, full surface bonding, ultrasonic bonding, heat fusion and the like. At least two layers constituting the composite sheet of the present invention are laminated and joined by a method appropriately selected from these general methods according to the combination of the surface layer and the reinforcing layer constituting the composite sheet of the present invention. Especially when employing adhesives using practical binders, these can be bonded by a combination of resinous binders, and the required average adhesive strength depends on the adhesiveness between two or more binders used. While maintaining the required adhesive strength distribution. The required distribution of the adhesive strength can also be obtained by changing the size of the adhesive spot in a sufficiently wide range using a single resin binder giving a specified average adhesive strength. The adhesion concentration can be controlled by the amount of the binder substance used. The binder may be applied by any method known in the art. This includes methods of applying as a dispersion or solution or as a binder film as a particulate or powdered material. If necessary, these binders can be activated by heating in a known manner.

The composite coating material thus obtained has a water pressure resistance of 500 H2 Omm or more and an air permeability of 1000 sec / 100.
cc or less, and the burst strength is 30 kgf or more. The coating material is preferably a polyolefin-based material that is stable to chemical substances and is hardly biodegradable, an ultraviolet absorber and a light stabilizer for improving weather resistance, an antioxidant for improving durability, and a surface protective agent. Such a chemical or resin may be applied or contained in the components constituting the coating material. By covering the upper layer of the landfill with such a composite covering material, it is possible to reliably prevent rainwater from entering the landfill, which is leachable wastewater, with very simple equipment, and at the same time, generate gas generated from waste in the landfill. In addition, the water vapor from which the waste water contained in the waste evaporates can be efficiently removed.

[0016]

The present invention will be described in detail with reference to the following examples. (Example 1) A nonwoven fabric sheet made of polypropylene was obtained by a melt blow method. Table 1 shows the physical properties of this nonwoven fabric sheet. The nonwoven sheet is made of a breathable waterproof layer, and has a porosity of 3
As the three-dimensional resin matrix layer, a commercially available polypropylene spunbond nonwoven fabric “TYPER” (registered trademark) manufactured by DuPont was used. Next, the non-woven fabric sheet and “Typer” are glued into a pattern (adhesion area: 15%, wet adhesion amount: 10 g / m ² ) with a gravure coater (X-Fla.
3520) to produce a composite coating material. Table 2 shows the physical properties of this composite coating material.

Example 2 Reference Example 100 parts of low-density polyethylene and heavy calcium carbonate 15
After mixing 0 parts with a Henschel mixer, pellets were prepared with a twin-screw extruder. Next, the sheet was formed into a sheet shape by a T-die extruder, and then uniaxially stretched 5 times to obtain a perforated thermoplastic film. Table 1 shows the physical properties of this film. This film was used as a breathable waterproof layer, and the same nonwoven fabric “typer” as in Example 1 was used as the porous three-dimensional resin. Thereafter, a composite coating material was prepared in the same manner as in Example 1. Table 2 shows the physical properties of this composite coating material.

Example 3 60 parts of polypropylene short fiber (fiber diameter 5.0 μm, fiber length 30 mm) and 40 parts of polyethylene synthetic pulp were dispersed in water and then paper-made, under the conditions of a temperature of 100 ° C. and a linear pressure of 60 kg / cm. After calendering, a synthetic fiber paper was obtained. Table 2 shows the physical properties of the synthetic fiber paper. Polyester taffeta (36 d / 75 filament, basis weight 100 g /
m ² ) was used. This was adhered in the same manner as in Example 1,
A composite coating was made. Table 2 shows the physical properties of this composite coating material.

(Comparative Example 1) A coating material comprising polyvinyl chloride which has been conventionally used. Table 2 shows the physical properties. Next, a method for evaluating the obtained composite coating material will be described.

(Evaluation 1) FIG. 1 is a cross-sectional view showing a simplified and modeled structure of a waste disposal site at the time of landfill completion for explaining one embodiment of a method for closing a waste disposal site according to the present invention. It is. In FIG. 1, reference numeral 1 denotes a depression before landfill,
An impermeable layer is provided on the surface. The landfill depression 1 in this embodiment has a height of 80 cm or more in a 100 cm square. Reference numeral 2 denotes a drainage pipe for collecting and draining sewage flowing down an impermeable layer portion provided along the side surface of the landfill depression 1. Reference numeral 3 denotes an organic sludge layer made of waste buried on the drainage pipe 2. The organic sludge layer in this evaluation has a volume of 470 liters and is deposited to a height of about 60 cm. Reference numeral 4 denotes a soil covering layer made of sandy soil covered on the organic sludge layer 3 and having a thickness of about 20 cm. 5
Is a covering material that covers the entire upper surface of the earth covering layer 4 of the landfill depression 1. Here, the moisture content of the organic sludge layer is 80%. While being left in this state for 21 days, the drainage amount, COD (chemical oxygen demand) contained in the drainage, and the change in the moisture content of the sludge layer were examined, and after 21 days, the odor when the coating material was turned over was sensory evaluated. . Table 3 shows the results.
Shown in As can be seen from Table 3, since the odor from the sludge layer cannot be detected by using the sheets of Examples 1 to 3,
This indicates that the odor has been removed.

Similar results are obtained for the numerical values of COD (chemical oxygen demand). However, it is presumed that this effect also includes a factor that hindered the anaerobic reaction by ventilation of the coating material. Further, it can be seen that the release of water vapor is also excellent in reducing sludge moisture. In other words, this indicates that the period for eliminating drained water from the landfill becomes shorter.
On the other hand, when the coating material of Comparative Example 1 is used, it can be seen from the increase in the odor and COD values of the sludge layer that gas from the sludge layer is accumulated.

(Evaluation 2) As shown in FIG.
A burial stone 7 of 0 mm in size is laid to a thickness of 20 cm, a covering material 6 is arranged thereon, and a thickness of 10 cm is placed on the covering material 6.
Wariguri stone 8 was laid. After the tractor shovel reciprocated 20 times on the surface of such a structure, water equivalent to 100 mm / hr was sprinkled with a hose in order to make it rain.
The upper part of the grime stone 8 was removed, and the observation of the wet state of the lower burial stone 7 and the tear of the coating material were visually judged. Table 4 shows the results. As can be seen from Table 4, Examples 1 to
The composite coating material of No. 3 has a sufficient waterproofing effect against water infiltrating from above, such as rainwater, and also has an excellent effect of preventing tearing.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

[Table 4]

The tensile strength tests shown in Tables 1 and 2 are based on JIS-L
Performed according to 1096. The sample width was 5 cm, the pulling speed was 10 cm / min, the gripping interval was 10 cm, and a constant speed elongation type test machine was used. A value obtained by averaging the vertical direction and the horizontal direction is shown. (a) The tear strength test was performed according to the JIS-L1096 A-1 method and the single tongue method. The pulling speed was 10 cm / min. A value obtained by averaging the vertical direction and the horizontal direction is shown. (b) Burst strength: Measured based on JIS-L1096 B method. (c) Weight: Measured based on JIS-L1092. (d) Thickness: Measured based on JIS-L1092. (e) Water resistance: Measured based on JIS-L1092 hydrostatic method. (f) Air permeability: Measured according to JIS-P8117 B method (Gurley method). (g) Moisture permeability: JIS-Z0208 (under conditions of 40 ° C / 90% RH)
Measure based on

[0028]

As described above, according to the present invention,
By covering the upper layer of the landfill with a nonwoven sheet of specific structure with specific properties, it is possible to prevent rainwater from entering the landfill, which is leached sewage, with very simple equipment. Sewage discharge can be suppressed. At the same time, the gas generated from the waste in the landfill and the water vapor evaporated from the wastewater contained in the waste can be efficiently removed, so that the danger of explosion due to the gas can be avoided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a simplified and modeled structure of a waste disposal site at the time of landfill completion for evaluating the performance of the composite coating material of the present invention.

FIG. 2 is a cross-sectional view showing the structure of a laminated structure constructed for testing the mechanical strength of solid-containing waste.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Landfill depression 2 Collection drainage pipe 3 Organic sludge layer 4 Soil covering layer 5 Coating material 6 Composite coating material 7 Lower wariguri stone 8 Upper wariguri stone

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ichiro Ikeda 1-8-1, Shimomeguro, Meguro-ku, Tokyo Asahi DuPont FlashSpan Products Inc. (56) References JP-A-4-228716 (JP, A) JP-A-7-276572 (JP, A) JP-A-5-123659 (JP, A) JP-A-6-47363 (JP, A) Japanese Utility Model 7-17815 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) B09B 1/00

Claims (3)

(57) [Claims] 1. A dressing for covering from above the waste disposal site used landfilled waste, meltblown
A porous waterproof layer selected from the group consisting of a non-woven fabric, a woven fabric, a knitted fabric, a felt film slit yarn and a net provided on at least one surface of the breathable waterproof layer, and a breathable waterproof layer selected from a method propylene nonwoven fabric or synthetic fiber paper. A composite covering material characterized by being integrally and layered with a three-dimensional resin matrix layer. 2. The method according to claim 1, wherein said air-permeable waterproof layer is made of a melt blown propylene resin.
The composite covering material used in a waste disposal site according to claim 1, wherein the composite covering material is a nonwoven fabric . 3. The composite covering material used in a waste disposal site according to claim 1, wherein said air-permeable waterproof layer is synthetic fiber paper made of synthetic fiber paper and hot-press calendered.