JP4500171B2 - Breathable water-impervious sheet, method for producing the same, and method for constructing rainwater permeation preventive layer - Google Patents

Description

  The present invention relates to a breathable water-impervious sheet used for covering a waste disposal site and a method for constructing a rainwater permeation preventive layer in a waste disposal site using the breathable impermeable sheet.

  A waste disposal site generally has a structure in which a recess is formed by excavating land, or a recess is formed using a recess in a mountainous area, and a waterproof sheet is laid on the bottom surface and slope of the recess. . In a waste disposal site with such a structure, waterproofing defects such as separation of waterproof sheet joints and damage to the sheet itself may occur, and if such waterproofing failure occurs, rainwater enters the waste disposal site. Wastewater containing harmful substances and pollutants flows into the ground without being led to the sewage treatment facility, causing groundwater contamination. Therefore, the waste disposal site where the waterproof failure has occurred is closed as a waste disposal layer with a water shielding sheet (capping sheet) covered with a water shielding sheet (capping sheet) so that rainwater does not enter. .

  However, if the waste is simply covered with a sheet having a high water-blocking performance, gas with a bad odor, harmful gas, and flammable gas generated due to decomposition of the waste by anaerobic bacteria will accumulate and the water-blocking sheet will become In some cases, such as damage or non-landing of the waste layer due to the progress of decomposition of the waste, the water shielding sheet may be damaged due to large distortion. There was a problem of contamination.

As a technology to prevent the generation of malodorous gas, harmful gas, flammable gas, etc. due to decomposition of waste by anaerobic bacteria at the waste disposal site, an air supply pipe with a vent hole in the bottom layer in advance is installed at the waste disposal site. There is a known technology that prevents the decomposition of waste by anaerobic bacteria by installing a gas-permeable impermeable sheet consisting of a porous film on the top of the waste layer and supplying air through the air supply pipe to the bottom layer Yes (Patent Document 1).
Japanese Patent No. 3118771

  However, in the technique disclosed in Patent Document 1, an air supply device must be installed in a waste disposal site in advance, and air must be continuously supplied even after being closed as an inappropriate waste disposal site. The construction cost of the waste disposal site is also expensive, the maintenance cost is high, and it is not economical. In addition, the porous films disclosed in Patent Document 1 are all expensive, and there is a need for a water-impervious sheet that is low in cost and has high air permeability.

  In the case where a waste disposal site constructed in the conventional configuration is closed as an inappropriate waste disposal site, the present invention prevents rainwater from penetrating into the waste disposal site and at the same time generates from waste. An object of the present invention is to provide a breathable water shielding sheet for covering waste that can discharge malodorous gases and the like, and a method for constructing a rainwater permeation preventive layer using the breathable water shielding sheet.

  The breathable impermeable sheet for covering waste of the present invention is 100 parts by weight in total of 30 to 99 parts by weight of a flexible polyurethane foam chip having an average size of 1 to 10 mm and 1 to 70 parts by weight of water absorbent resin particles. It contains 1 to 40 parts by weight of a binder.

  The breathable impermeable sheet for waste coating with the above configuration has both the imperviousness of preventing rainwater from penetrating into the waste disposal site and the high breathability capable of discharging gas generated from waste. is there.

  When the amount of the flexible polyurethane foam chip used is less than 30 parts by weight, the ratio of the water-absorbent resin and the binder becomes too high, and the flexibility of the sheet is lowered, and when it exceeds 99 parts by weight, the ratio of the water-absorbent resin is lowered. As a result, the water shielding performance decreases. When the ratio of the water-absorbent resin is less than 1 part by weight, the water shielding performance is not sufficient, and when it exceeds 70 parts by weight, the flexibility of the sheet is lowered. On the other hand, if the binder ratio is too small, the strength of the sheet decreases, and if it is too large, the air permeability of the sheet decreases.

The breathable water-impervious sheet is not particularly limited as long as necessary performance is exhibited, but the thickness is preferably 1 to 50 mm, and more preferably 2 to 20 mm. Breathable vent temper water barrier sheet is preferably 200m ³ / m ² / 24hr or more. The air permeability is preferably as large as possible as long as it has the necessary water barrier properties.

The breathable water-impervious sheet for covering waste according to the present invention preferably has a water permeability coefficient in the vertical direction of 1 × 10 ⁻⁶ cm / sec or less.

When the hydraulic conductivity in the vertical direction exceeds 1 × 10 ⁻⁶ cm / sec, the amount of rainwater that permeates into the waste layer increases and groundwater contamination occurs. The vertical direction is the vertical direction when the waste layer is coated, that is, the thickness direction of the sheet.

  It is preferable that the breathable water-impervious sheet for covering the above-mentioned waste is one in which a reinforcing porous resin membrane is further laminated on at least one side.

  By adopting a breathable water-impervious sheet with such a configuration, the strength of the breathable impermeable sheet is increased, making it easier to construct, and at the same time, the number of construction steps on the waste layer is reduced, making it easy to close inappropriate waste disposal sites. Can be done. In addition, when water permeates after construction, the breathable water-impervious sheet with a high content of water-absorbing resin particles decreases in strength, but the lamination of the reinforcing resin porous membrane prevents damage even if unevenness occurs. Is done. The reinforcing resin porous membrane is preferably laminated on both sides because the strength of the breathable water-impervious sheet becomes higher.

  Another aspect of the present invention is a method for producing a breathable water-impervious sheet for covering waste, which is a total of 30 to 99 parts by weight of a flexible polyurethane foam chip having an average size of 1 to 10 mm and 1 to 70 parts by weight of water absorbent resin particles. 1 to 40 parts by weight of a binder is added and mixed with respect to 100 parts by weight, and the resulting mixture is formed into a sheet shape.

  Breathable water-proof sheet for waste coating that has both the water-blocking performance to prevent rainwater from penetrating into the waste disposal site and the high breathability that can discharge the gas generated from the waste by the manufacturing method of the above configuration Can be manufactured.

  In the above-described method for producing a breathable water-impervious sheet for covering waste, it is preferable to laminate a reinforcing resin porous film on at least one surface by a frame laminating method.

  With this manufacturing method, it is easy to construct a breathable water-impervious sheet that increases the strength and makes it easier to construct and at the same time reduces the number of man-hours on the waste layer and can easily close the inappropriate waste disposal site. And it can manufacture at low cost. In addition, the obtained air-permeable and water-impervious sheet is prevented from being damaged even when water penetrates after construction. The reinforcing resin porous membrane is preferably laminated on both sides because the strength of the breathable water-impervious sheet becomes higher.

Another aspect of the present invention is a method for constructing a rainwater infiltration prevention layer that covers the top surface of waste in a waste disposal site,
The rainwater permeation prevention layer is formed by constructing a breathable impermeable sheet on at least waste,
The breathable water-impervious sheet contains 1 to 40 parts by weight of binder with respect to 100 parts by weight in total of 30 to 99 parts by weight of flexible polyurethane foam chips having an average size of 1 to 10 mm and 1 to 70 parts by weight of water-absorbent resin particles. It is characterized by being a breathable water-impervious sheet.

  With this construction method, when a waste disposal site that has been implemented by a conventional and simple method is closed as an inappropriate waste disposal site, it prevents the infiltration of rainwater and at the same time fills the gas generated from the waste. A waterproof coating (capping) that can be effectively discharged through the layers can be performed.

  In the construction method of the rainwater permeation preventive layer, it is preferable that the breathable water-impervious sheet has a reinforcing resin porous film laminated on at least one side.

  By using a breathable impermeable sheet with such a structure, the strength of the breathable impermeable sheet is increased, making it easier to construct, and at the same time the number of construction steps for the waste layer is reduced, and the inappropriate waste disposal site is closed. It can be performed simply. In addition, when water permeates after construction, the breathable water-impervious sheet having a higher content of water-absorbing resin particles decreases in strength, but breakage is prevented by lamination of the reinforcing resin porous membrane. Use of a breathable water-impervious sheet in which reinforcing resin porous membranes are laminated on both sides is preferable because of its higher strength.

  In the construction method of the rainwater permeation prevention layer, it is preferable to construct the water shielding sheet by laminating a plurality of layers.

  When flexible polyurethane foam waste is used in the manufacture of breathable water shielding sheets, polyurethane foams with different breathability are mixed, resulting in variations in breathability and strength in the breathable water shielding sheets formed. Although such non-uniformity may occur, such a configuration reduces the occurrence of water passage portions and the like due to these non-uniformity of the entire breathable impermeable sheet layer.

  In the construction method of the rainwater permeation preventive layer, it is preferable to further provide a reinforcing sheet layer in addition to the breathable water shielding sheet.

  With such a configuration, the waste disposal site is further reduced in the risk of damage to the breathable water-impervious sheet. The reinforcing sheet layer may be above or below the breathable water-impervious sheet layer, and may be disposed on both sides.

  The breathable impermeable sheet for covering waste of the present invention is 100 parts by weight in total of 30 to 99 parts by weight of a flexible polyurethane foam chip having an average size of 1 to 10 mm and 10 to 70 parts by weight of water absorbent resin particles. It is formed by molding a mixture containing 1 to 40 parts by weight of a binder.

  If the size of the polyurethane foam (meaning the long side of the chip) is less than 1 mm, it is too fine and difficult to handle.

  The breathable water-impervious sheet is formed by heating, drying or heating a mixture of a chip-like soft polyurethane foam, a granular water-absorbent resin and a binder that have been crushed or chipped to an average size of 1 to 10 mm, Molded by curing. The molding may be performed by using a mold to form one sheet at a time, or after forming into a block shape and slicing. Alternatively, a mixture of a chip-like flexible polyurethane foam, a granular water-absorbing resin, and a binder may be continuously supplied, and formed into a continuous sheet using a continuous heat forming apparatus such as a double conveyor.

  In the case of molding using a mold, the chip-like polyurethane foam, the granular water-absorbing resin and the binder are mixed in advance with the chip-like polyurethane foam and the granular water-absorbing resin. May be fixed in a mold, and a binder may be added to these, or a chip-like polyurethane foam and a granular water-absorbent resin may be mixed well in advance, and a binder may be sprayed thereon. In addition, it may be charged in the mold after adding.

  The “chip shape” is used as a concept including not only the original thin piece and thin piece but also a small block, a sphere, a square, and a piece. Chip-like flexible polyurethane foam can use waste of flexible polyurethane foam such as seat cushion pads and mattresses, and can produce a low-cost breathable waterproof sheet and at the same time reduce polyurethane foam waste. It is done.

  The binder is preferably one or a mixture of two or more of urethane, acrylic and vinyl acetate.

  According to said structure, it is convenient that it is excellent in the bond strength of a polyurethane foam and a water absorbing resin, and can maintain easily the softness which a polyurethane foam has after a coupling | bonding.

  As the binder, an isocyanate prepolymer binder is particularly preferable among the above because a sheet having excellent strength can be obtained.

  The isocyanate prepolymer binder is obtained by reacting a polyol compound such as polyester polyol or polyether polyol having an average molecular weight of 500 to 8000 with a polyisocyanate compound at an NCO / OH equivalent ratio of 1.5 to 2.5. The use of an isocyanate prepolymer binder using polyoxypropylene polyol (PPG) as the main component of the polyol compound is particularly preferable because it has the required fluidity without adding a solvent and is easy to handle. .

  When using an isocyanate prepolymer-based binder, the polyurethane foam and the particulate water-absorbing resin are mixed and stirred, then the binder is added and mixed thoroughly, and these are charged into the mold. It is preferable to introduce water vapor into the sealed mold.

  According to this configuration, the chip-like polyurethane foam and the particulate water-absorbing resin are fixed and integrated in a predetermined-shaped molding die, and a molded product can be manufactured more uniformly and reliably with a high yield. The isocyanate prepolymer rapidly reacts and crosslinks with heated steam to form a breathable water-impervious sheet. In the case of continuous production of sheets, a method of forming a double conveyor with a porous metal belt and supplying heated steam from the inside is exemplified as a preferred production method.

  As the water-absorbing resin constituting the breathable water-impervious sheet of the present invention, a known water-absorbing resin can be used, and specifically, for example, a crosslinked poly (meth) acrylic acid, poly (meth) acrylic Cross-linked acid salt, cross-linked poly (meth) acrylate ester having sulfonic acid group, cross-linked poly (meth) acrylate ester having polyoxyalkylene group, cross-linked poly (meth) acrylamide, (meth) acrylate Cross-linked copolymer of (meth) acrylamide and (meth) acrylic acid hydroxyalkyl and (meth) acrylate cross-linked, polydioxolane cross-linked, cross-linked polyethylene oxide, cross-linked polyvinyl pyrrolidone, sulfonated polystyrene cross-linked , Saponified product of cross-linked polyvinyl pyridine, starch-poly (meth) acrylonitrile graft copolymer Starch-poly (meth) acrylic acid (salt) graft crosslinked copolymer, reaction product of polyvinyl alcohol and maleic anhydride (salt), crosslinked polyvinyl alcohol sulfonate, polyvinyl alcohol-acrylic acid graft copolymer, poly Examples include isopylene maleic acid (salt) crosslinked polymer.

  These water-absorbing resins may be used alone or in combination of two or more as required. Furthermore, other resins can be used in combination with the water-absorbing resin to such an extent that various properties (such as the water absorption capacity) of the water-absorbing resin are not impaired.

  Moreover, resin obtained by superposing | polymerizing the monomer component containing the ethylenically unsaturated monomer which has water solubility, and a crosslinking agent as needed can be used as a water absorbing resin. A water-absorbent resin obtained by (co) polymerizing an ethylenically unsaturated monomer is superior in swelling property against water and is generally inexpensive. The above crosslinking agent is not particularly limited. Further, it is also preferable to form a water-absorbing resin by adding a crosslinking agent to a linear polymer to perform crosslinking, or by irradiating with an electron beam and crosslinking.

  Specific examples of the ethylenically unsaturated monomer include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid, vinyl sulfonic acid, and (meth) allyl sulfonic acid. 2- (meth) acrylamido-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2- (meth) acryloylpropanesulfonic acid, and alkali metal salts and ammonium salts of these monomers; N , N-dimethylaminoethyl (meth) acrylate and quaternized products thereof; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, diacetone (meth) acrylamide, N- Isopropyl (meth) acrylamide, (meth) acryloylmorpholine (Meth) acrylamides such as, and derivatives of these monomers; hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; polyethylene glycol mono (meth) acrylate Polyalkylene glycol mono (meth) acrylates such as polypropylene glycol mono (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate and methoxypolypropylene glycol mono (meth) acrylate; N-vinyl-2-pyrrolidone, N-vinylsuccinimide, etc. N-vinyl monomers such as B-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, etc. Body; vinyl methyl ether; but like, but it is not particularly limited. These ethylenically unsaturated monomers may be used alone or in combination of two or more.

  Of the ethylenically unsaturated monomers exemplified above, an ethylenically unsaturated monomer having a nonionic group and / or a sulfonic acid (salt) group is more preferred. Examples of such monomers include 2- (meth) acrylamide-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2- (meth) acryloylpropanesulfonic acid, (meth) acrylamide, and hydroxyalkyl. (Meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate and the like can be mentioned. Furthermore, an ethylenically unsaturated monomer having a polyoxyalkylene group is particularly preferred.

  Further, when two or more ethylenically unsaturated monomers are used in combination as the monomer component, the ethylenically unsaturated group having a nonionic group and / or a sulfonic acid (salt) group in the monomer component is used. The monomer ratio is more preferably 1% by weight or more, and further preferably 10% by weight or more. When the above ratio is less than 1% by weight, even if a water absorbent resin obtained by polymerizing the monomer component is used, the performance may not be further improved.

  As a more preferable combination when two or more ethylenically unsaturated monomers are used in combination as the monomer component, for example, a combination of (meth) acrylic acid alkali metal salt such as sodium acrylate and acrylamide, (meta ) A combination of an alkali metal salt of acrylic acid and methoxypolyethylene glycol mono (meth) acrylate is exemplified, but is not particularly limited.

  Although the water-absorbing resin is obtained by polymerizing the monomer component, the method for polymerizing the monomer component, that is, the method for producing the water-absorbing resin is not particularly limited. In addition, the average molecular weight, shape, average particle diameter, etc. of the water-absorbent resin can be set according to the composition and pH of the solution to be absorbed, the working environment, the combination with the base material when combined with other base materials, etc. Although not particularly limited, it is more desirable to use a water absorbent resin having an average particle diameter of 2,000 μm or less, more preferably 500 μm or less, further preferably 200 μm or less, and particularly preferably 100 μm or less. Furthermore, a particularly preferable average particle diameter is 70 μm or less. By using the water absorbent resin having such an average particle diameter, the dispersibility or mixing property of the water absorbent resin is improved. Moreover, it is easy to increase the amount of the water-absorbent resin per unit area in a uniform state, and the performance can be further improved.

  As the reinforcing resin porous membrane, a material that has high strength and does not impair the breathability of the breathable water-impervious material composed of a flexible polyurethane foam chip, water-absorbent resin particles, and a binder can be used without limitation. Is a woven or non-woven fabric made of organic fiber, glass fiber, etc., resin mesh such as polypropylene, stretched or narrow tape of polyolefin resin in a mesh shape (for example, the product name Nisseki Warif (Nisseki Plast) ) Etc. are suitable.

  Lamination of these reinforcing resin porous membranes and a breathable water-impervious sheet composed of a polyurethane foam chip, a water-absorbing resin, and a binder can be performed by a known method, for example, an adhesive method using an adhesive or a frame laminating method. In the case of producing a breathable water-impervious sheet in a mold, a method of supplying it into the mold and laminating at the time of producing the breathable impermeable sheet is exemplified.

  FIG. 1 is a cross-sectional view illustrating an inappropriate waste disposal site closed using a breathable water-impervious sheet of the present invention. In the waste disposal site, the cross-sectional shape excavated in the land G is constructed by installing a waterproof sheet 14 on the bottom and slope of the substantially trapezoidal recess, and the waste 16 is put in the recess. The upper surface of the waste 16 layer is covered with a breathable water-impervious sheet 10, the outer surface thereof is covered with the reinforcing resin porous membrane 12, and the embankment layer 18 is formed as the outermost layer. A drainage groove 20 for discharging rainwater in the embankment portion is provided at the end position of the breathable water-impervious sheet 10.

Preferred examples of the breathable water-impervious sheet of the present invention are shown below. As the flexible polyurethane foam chip, one having a nominal size of 11.2 mm defined in JIS Z 8801 and not passing a nominal size of 1 mm was used. The measuring method of the air permeability and the water permeability coefficient is as follows.
(Air permeability) It measured about the sample of the dry state based on the fragile method of JISL1096 regulation.
(Water permeability coefficient) Measured according to ASTM D 5887.

(Production Example 1)
An NCO group-terminated prepolymer obtained by reacting polyoxypropylene glycol (PPG) having a number average molecular weight of 1000 and diphenylmethane diisocyanate (MDI) at NCO / OH = 2.0 was used as a binder. This prepolymer was liquid at room temperature and was highly fluid. 83 parts by weight of a flexible polyurethane foam chip crushed to a size of 1 to 10 mm and 17 parts by weight of Aquacat CS-6HM (water absorbent resin) manufactured by Nippon Shokubai Co., Ltd. having an average particle size of 50 μm are uniformly mixed, A mixture in which a binder is spray-applied to 8 parts by weight with respect to 100 parts by weight of the water-absorbent resin is placed in a mold, heated at 120 ° C. and heated and cured for 5 minutes, and then a breathable water-impervious sheet. A block 1 was prepared.

This breathable impermeable sheet block 1 was sliced into thicknesses of 3 mm, 4 mm, 5 mm, 8 mm, and 10 mm to produce a breathable impermeable sheet. For the 3 mm, 5 mm, 8 mm, and 10 mm sheets, the air permeability was measured independently. For the 4 mm and 5 mm sheets, the air permeability was measured by stacking two sheets, and the results are shown in Table 1. Further, the water permeability coefficient in the vertical direction was measured for one water-impervious sheet having a thickness of 5 mm, and the measurement result was 3.1 × 10 ⁻⁸ cm / sec.

(Production Example 2)
The amount of the flexible polyurethane foam chip used is 67 parts by weight, the amount of Aquaric CS-6HM used is 33 parts by weight, and the amount of binder used is 10 parts by weight with respect to 100 parts by weight of the total of the polyurethane chip and the water absorbent resin. Except for the points described above, a block 2 for a breathable impermeable sheet was produced in the same manner as in (Production Example 1).

This breathable water shielding sheet block 2 was also prepared by slicing a sheet having the same thickness as in (Production Example 1), and the breathability was measured. Table 1 shows the results. Moreover, when the water permeability coefficient of the perpendicular direction was performed about 1 sheet | seat of thickness 5mm, the measurement result was 2.6 * 10 < ^-9 > cm / sec.

以上のように、いずれの通気性遮水シートも通気性が大きく、かつ透水性の小さなものであり、不適正な廃棄物処理場の廃棄物層を被覆して閉鎖するのに適した通気性と遮水性を有するものであった。

As described above, all of the air-permeable and water-impervious sheets have high air permeability and low water permeability, and are suitable for covering and closing the waste layer of an inappropriate waste disposal site. And water-blocking.

(Production Example 3)
Nisseki Warif LX-14 (Nisseki Plast) as a reinforcing resin porous membrane is laminated on both sides by the frame laminating method on the 5 mm thick breathable water-impervious sheet produced in Production Example 1 for reinforcement. A breathable water-impervious sheet having a resin porous membrane layer was produced. This breathable water-impervious sheet had a tensile strength of 90 N / cm or more and an elongation of 15% or more (based on JIS L 1908), satisfying the characteristics required for the breathable impermeable sheet.

Cross-sectional view illustrating an inappropriate waste disposal site covered with a breathable water-impervious sheet and a reinforcing porous resin membrane

Explanation of symbols

10 Breathable water shielding sheet 12 Reinforcing resin porous membrane 16 Waste

Claims (8)

  Disposal characterized by containing 1 to 40 parts by weight of binder for 100 parts by weight in total of 30 to 99 parts by weight of flexible polyurethane foam chips having an average size of 1 to 10 mm and 1 to 70 parts by weight of water absorbent resin particles Breathable waterproof sheet for covering objects. The breathable water-impervious sheet for covering waste according to claim 1, wherein the water permeability coefficient in the vertical direction is 10 ^-6 cm / sec or less.   The breathable water-impervious sheet for covering wastes according to claim 1 or 2, further comprising a reinforcing resin porous film laminated on at least one side.   1 to 40 parts by weight of a binder was added to and mixed with 30 to 99 parts by weight of a flexible polyurethane foam chip having an average size of 1 to 10 mm and 1 to 70 parts by weight of water-absorbent resin particles. A method for producing a breathable water-impervious sheet for covering waste, wherein the mixture is formed into a sheet.   The method for producing a breathable waterproof sheet for covering waste according to claim 4, further comprising laminating a reinforcing resin porous film on at least one surface by a frame laminating method. A method of constructing a rainwater infiltration prevention layer that covers the top surface of waste at a waste disposal site,
The rainwater permeation prevention layer is formed by constructing a breathable impermeable sheet on at least waste,
The breathable water-impervious sheet contains 1 to 40 parts by weight of binder with respect to 100 parts by weight in total of 30 to 99 parts by weight of flexible polyurethane foam chips having an average size of 1 to 10 mm and 1 to 70 parts by weight of water-absorbent resin particles. A method for constructing a rainwater permeation preventive layer that is a breathable water shielding sheet.   The method for constructing a rainwater penetration preventing layer according to claim 6, wherein the breathable water-impervious sheet is obtained by laminating a reinforcing resin porous film on at least one side.   The construction method for a rainwater permeation preventive layer according to claim 6 or 7, wherein the water shielding sheet is constructed by laminating a plurality of layers.

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