JP2013087492A - Waterproof sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waterproof sheet which is used for, for example, tunnel construction in the natural ground and paved road construction on a slope of the natural ground to prevent water from springing from the natural ground, and has a structure where a non-woven cloth and a water-impervious sheet are hardly peeled from each other and spring water can pass between the non-woven cloth and the water-impervious sheet, by improving an adhesion force between the non-woven cloth and the water-impervious sheet.SOLUTION: A waterproof sheet formed by bonding a water-impervious sheet on one surface of a non-woven cloth contains 20-80 mass% of ethylene-vinyl acetate copolymer and 20-80 mass% of polyethylene. The non-woven cloth and the water-impervious sheet are bonded to each other by spot bonding or linear bonding.

Description

  The present invention relates to a waterproof sheet for waterproofing spring water from a natural ground and the like to protect a structure.

  Conventionally, when constructing a tunnel in a natural ground, a waterproof sheet is placed between the primary lining concrete of the tunnel and the secondary lining concrete, and spring water from the primary lining concrete side (spring from the underground into the tunnel). Water) is prevented from leaking to the secondary lining concrete side. In addition, when constructing a paved road on the natural slope, a waterproof sheet is placed between the natural slope and the embankment, and measures are taken to prevent the spring water from the natural ground from leaking to the embankment. .

  For example, in Patent Document 1 (Japanese Patent Laid-Open No. 63-315800), a sheet-like net is laminated on at least a part of one surface of a buffer sheet, and an impermeable sheet is provided on the other surface of the buffer sheet. A laminated waterproof sheet is disclosed. This waterproof sheet can reliably discharge wastewater with a lot of earth and sand without clogging, guarantees good running water performance over a long period of time, and the cushioning effect of the cushioning sheet makes it a protrusion during tunnel construction. The impervious sheet is reliably protected against permanent use.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2000-080895) discloses a water shielding sheet made of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 30 to 90% by weight. This water shielding sheet has excellent adhesion to waterproof materials such as hydraulic materials, exhibits a high water shielding effect, has moderate flexibility, and is excellent in handling and workability during water shielding work. Yes.

  Patent Document 3 (Japanese Patent Laid-Open No. 2001-115791) describes two or more types of ethylene-vinyl acetate copolymers (hereinafter also referred to as EVA) having different vinyl acetate contents (hereinafter also referred to as VA contents). A tunnel waterproof sheet comprising a mixture as a main component is disclosed. This waterproof sheet is obtained by blending, for example, EVA having a low VA content with a VA content of 10% by mass or less and EVA having a slightly higher VA content than the EVA currently used, thereby reducing the average VA lower than that of the EVA currently used. Excellent low temperature flexibility in content.

  Patent Document 4 (Japanese Patent Laid-Open No. 06-032950) discloses an ethylene-vinyl acetate copolymer or a polymer comprising a blend component of 70% by weight or more of ethylene-vinyl acetate copolymer and 30% by weight or less of low-density polyethylene. A waterstop sheet comprising components, aluminum hydroxide, and alkaline earth metal oxide is disclosed. This waterproof sheet has excellent flame retardancy and high tensile strength, is flexible and has good workability.

JP-A-63-315800 JP 2000-080895 A JP 2001-115791 A Japanese Patent Application Laid-Open No. 06-032950

  However, the sheets obtained in Patent Documents 1 to 3 described above have poor adhesive strength between the nonwoven fabric and the water-impervious sheet and are bonded almost over the entire surface in order to prevent peeling between the nonwoven fabric and the water-impervious sheet. There was a need to do. And the waterproof sheet with the non-woven fabric and the water-impervious sheet bonded to almost the entire surface functions as a water conduit for the spring, but the drainage performance is sufficient when a large amount of spring water is generated due to rain. It was something that could not be secured.

  In view of such a problem, the present invention improves the adhesive force between the nonwoven fabric and the water-impervious sheet, so that the nonwoven fabric and the water-impervious sheet are not easily separated, and spring water is generated between the nonwoven fabric and the water-impervious sheet. Provide a waterproof sheet that can pass through.

  The present inventors first examined the configuration of a waterproof sheet that is composed of a nonwoven fabric and a water-impervious sheet and that can drain water even when there is a lot of spring water in a waterproof sheet having a drainage function. And it discovered that the adhesion part of a nonwoven fabric and a water-impervious sheet inhibited the flow of the spring water between a water-impervious sheet and a nonwoven fabric, and examined the adhesion part paying attention to this. However, a waterproof sheet using a water-proof sheet made of a conventional ethylene-vinyl acetate copolymer has a weak adhesive force between the water-proof sheet and the nonwoven fabric, and reduces the adhesion between the nonwoven fabric and the water-proof sheet as it is. And when spring water flowed between the impermeable sheet and the nonwoven fabric, it was confirmed that the nonwoven fabric was lifted and the impermeable sheet and the nonwoven fabric were peeled off. Therefore, the present inventors have studied the resin component constituting the water shielding sheet in order to improve the adhesive force, and the water shielding sheet containing ethylene-vinyl acetate copolymer and polyethylene at a predetermined ratio is a nonwoven fabric. Regardless of the material, it has been found that the waterproof sheet and the nonwoven fabric are excellent in adhesive strength, and a waterproof sheet that does not peel can be configured without bonding the nonwoven fabric and the waterproof sheet completely. .

  That is, the present invention is a waterproof sheet in which a waterproof sheet is bonded to one surface of a nonwoven fabric, and the waterproof sheet includes 20% by mass to 80% by mass of an ethylene-vinyl acetate copolymer, polyethylene 20% by mass to 80% by mass, and the non-woven fabric and the water-impervious sheet are point-bonded or linearly bonded.

  In the waterproof sheet of the present invention, the nonwoven fabric and the water-impervious sheet are difficult to peel off, and can be effectively drained when spring water or the like is passed between the nonwoven fabric and the water-impervious sheet.

It is the schematic which shows the cross section of this invention. It is the schematic which shows the cross section of this invention containing a sheet-like net-like body. It is the schematic which shows an example of the surface of a sheet-like net-like body. It is the schematic which shows an example of the usage pattern of this invention.

  The waterproof sheet of the present invention is a waterproof sheet formed by adhering a waterproof sheet to one surface of a nonwoven fabric, and the waterproof sheet includes 20% by mass to 80% by mass of an ethylene-vinyl acetate copolymer, The waterproof sheet is characterized by comprising 20% by mass to 80% by mass of polyethylene, and the non-woven fabric and the water shielding sheet are bonded in a dotted or linear manner.

  In the present invention, the water shielding sheet contains 20% by mass to 80% by mass of ethylene-vinyl acetate copolymer and 20% by mass to 80% by mass of polyethylene. With this configuration, the water-impervious sheet has excellent adhesive strength, and a water-impervious sheet excellent in adhesive strength with the nonwoven fabric can be obtained regardless of the nonwoven fabric material.

  In the present invention, the non-woven fabric and the water-impervious sheet are bonded to each other in a dotted or linear manner. The waterproof sheet using the conventional water-impervious sheet is weak in the adhesive force between the nonwoven fabric and the water-impervious sheet. When passing between the two, there was a problem that the nonwoven fabric and the water-impervious sheet peeled off due to flowing water pressure or the like. However, since the present invention is excellent in the adhesive force between the water-impervious sheet and the nonwoven fabric, the nonwoven fabric and the water-impervious sheet are hardly peeled even when the nonwoven fabric and the water-impervious sheet are bonded in a dotted or linear manner. .

  For example, in tunnel construction, when the waterproof sheet of the present invention is used by being disposed between primary lining concrete and secondary lining concrete, spring water from the primary lining concrete side is used as a nonwoven fabric and a water shielding sheet. Therefore, there is little or no occurrence of cracks in the concrete due to the spring water moving to the secondary lining concrete side.

  Or, for example, when constructing a paved road on a natural mountain slope, when using the waterproof sheet of the present invention between the natural mountain slope and embankment, the spring water from the natural mountain side is used as a nonwoven fabric and water shielding Since the water can be drained by passing between the sheets, spring water does not move to the embankment, and landslide or the like does not occur.

  In the present invention, the polyethylene constituting the water shielding sheet is preferably a linear low density polyethylene. When the polyethylene constituting the water shielding sheet is a linear low density polyethylene, the waterproof strength of the water shielding sheet is improved and a waterproof sheet that is not easily broken can be obtained.

  In the present invention, a sheet-like mesh body in which a plurality of continuous filaments having a thickness of 0.1 mm to 10 mm are irregularly intersected on the other surface of the nonwoven fabric (hereinafter also simply referred to as a net-like body or a sheet-like net-like body). Are preferably integrated. The sheet-like net having such a structure mainly functions as a water conduit for draining spring water or the like to the outside.

  Hereinafter, the waterproof sheet of the present invention will be described in detail.

(Nonwoven fabric)
The nonwoven fabric which comprises the waterproof sheet of this invention plays the role which prevents that a water-impervious sheet | seat is damaged by uneven | corrugated | grooved parts, such as concrete, a natural ground, or a sheet-like net-like body. For example, in tunnel construction, when secondary lining concrete is placed, the water shielding sheet is prevented from being damaged by the placement pressure acting on the waterproof sheet. If the water-impervious sheet is damaged, there is a high possibility that the secondary lining concrete will crack. Moreover, the nonwoven fabric itself may function as a water conduit.

  Any fiber can be used as the fiber constituting the nonwoven fabric. Examples thereof include polyolefin resins such as polyethylene, polypropylene, and polybutene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polyamide resins such as nylon 6 and nylon 66. You may be comprised from a synthetic resin. Especially, it is preferable that the fiber which comprises a nonwoven fabric contains polyolefin resin from a viewpoint which is excellent in alkali resistance and a weather resistance. Moreover, tear strength can also be given to a waterproof sheet by using the nonwoven fabric which consists of an aramid fiber and carbon fiber.

Nonwoven fabric, it is preferred basis weight is ^{80g / m 2 ~500g / m 2} . It becomes easy to satisfy | fill the range of the below-mentioned tensile strength as the fabric weight of a nonwoven fabric is 80 g / m < ² > or more. Further, if the basis weight of the nonwoven fabric is 800 g / m ² or less, it is not too heavy and construction is easy. From the viewpoint of obtaining such an effect more remarkably, the basis weight of the nonwoven fabric is more preferably ^{100g / m 2 ~300g / m 2} .

The nonwoven fabric preferably has a thickness of 0.5 mm to 20 mm. When the thickness of the nonwoven fabric is 0.5 mm or more, the effect of preventing the water shielding sheet from being damaged by the protrusions is more excellent. When the thickness of the nonwoven fabric is 20 mm or less, the nonwoven fabric is difficult to break or peel in the thickness direction. From the viewpoint of more prominently obtaining such effects, the thickness of the nonwoven fabric is more preferably 1 mm to 10 mm. The thickness of the nonwoven fabric is particularly preferably 2 mm or more. When the thickness of the nonwoven fabric is 2 mm or more, the spring water easily passes through the nonwoven fabric, and the nonwoven fabric functions as a water conduit. In addition, the thickness of a nonwoven fabric is measured in the state which applied the load of 2.94 cN per cm < ² > according to JISL10968.5.

  The nonwoven fabric may be a long fiber nonwoven fabric such as a spunbond nonwoven fabric or a melt blown nonwoven fabric, or a short fiber nonwoven fabric such as a needle punch nonwoven fabric, a spunlace nonwoven fabric, or a thermal bond nonwoven fabric. Especially, it is preferable that a nonwoven fabric is the nonwoven fabric which entangled the spun bond nonwoven fabric by the needle punch process. Such a non-woven fabric is easy to obtain the above-mentioned thickness at low cost, and is more excellent in the effect of protecting the water shielding sheet from the projections.

  Although the fiber which comprises a nonwoven fabric is not specifically limited, Single fiber fineness may be 1 dtex-100 dtex. When a fiber having a fineness of 1 dtex to 100 dtex is used, it is easy to obtain a nonwoven fabric that satisfies the later-described tensile strength and tear strength.

  When a nonwoven fabric is a short fiber nonwoven fabric, the fiber which comprises a nonwoven fabric is although it does not specifically limit, It is preferable that fiber length is 10 mm-200 mm. When the fiber length is 10 mm to 200 mm, it is easy to obtain a nonwoven fabric that satisfies the later-described tensile strength and tear strength.

  The nonwoven fabric may be composed of one type of fiber, or may be a nonwoven fabric in which two or more fibers are mixed. Moreover, the nonwoven fabric may be a single-layer nonwoven fabric composed of a single-layer web, or may be a laminated nonwoven fabric obtained by laminating two or more webs. Further, the nonwoven fabric may be composed of fibers made of a single component resin, or may be a composite fiber using two or more resins. The cross-sectional shape of such a fiber is not limited to a round cross section, but may be a different cross-section fiber such as a concentric circular shape, a wedge-shaped divided type, a slit-shaped divided type, a hollow type, a triangular type, a Y type, or a square type.

  The nonwoven fabric preferably has irregularities on the surface facing the water-impervious sheet. The height of the convex portion is preferably 0.5 mm to 10 mm, and more preferably 1 mm to 7 mm. When the surface facing the nonwoven fabric water-impervious sheet has an uneven portion, a space through which spring water passes increases between the nonwoven fabric and the water-impervious sheet, thereby improving drainage efficiency.

  The nonwoven fabric preferably has a tensile strength measured according to JIS L 1096 of 500 N / 5 cm or more, and more preferably 700 N / 5 cm or more. If the tensile strength is 500 N / 5 cm or more, the nonwoven fabric is difficult to break. The preferable upper limit of the tensile strength is 3000 N / 5 cm.

  The non-woven fabric has an elongation measured according to JIS L 1096 of preferably 40% or more, and more preferably 60% or more. When the elongation is 40% or more, it becomes easy to follow the elongation of the water-impervious sheet described later, and the construction is easy along the arc surface of the tunnel and the curved slope of the natural ground. A preferable upper limit of elongation is 500%.

  The nonwoven fabric preferably has a tear strength measured in accordance with JIS L 1096 (single tank method) of 80 N or more, and more preferably 120 N or more. If the tear strength is 80 N or more, the nonwoven fabric is difficult to tear. A preferable upper limit of the tear strength is 500N.

(Water shielding sheet)
The water shielding sheet constituting the waterproof sheet of the present invention plays a role of preventing the spring water from shifting to the concrete or embankment side. For example, in tunnel construction, a waterproof sheet is stretched on the primary lining concrete side so that spring water generated from the underground side does not flow out to the secondary lining concrete side beyond the impermeable sheet. When spring water moves to the secondary lining concrete, cracks are likely to occur in the secondary lining concrete, and the concrete may collapse.

  The water shielding sheet contains 20% by mass to 80% by mass of an ethylene-vinyl acetate copolymer and 20% by mass to 80% by mass of polyethylene. With this configuration, the adhesive strength of the water shielding sheet is increased, and the nonwoven fabric and the water shielding sheet can be firmly bonded.

  The water shielding sheet needs to contain 20% by mass to 80% by mass of an ethylene-vinyl acetate copolymer. When the content of the ethylene-vinyl acetate copolymer in the water-impervious sheet is 20% by mass or more, the water-impervious sheet has good water shielding properties due to the resin characteristics of the ethylene-vinyl acetate copolymer. For example, since the spring water that has passed through the primary lining concrete or rock bolt does not move to the secondary lining concrete side by the water shielding sheet, cracks are unlikely to occur in the secondary lining concrete. Furthermore, due to the resin characteristics of the ethylene-vinyl acetate copolymer, the water shielding sheet does not become hard even in a low temperature environment of, for example, 10 ° C. or less, and the followability to the construction surface is maintained. From the viewpoint of more prominently obtaining such an effect, the water shielding sheet preferably contains 40% by mass or more of an ethylene-vinyl acetate copolymer. Moreover, the polyethylene mentioned later can fully be contained as content of the ethylene-vinyl acetate copolymer in a water shielding sheet is 80 mass% or less. From the viewpoint of obtaining such effects more remarkably, the water shielding sheet preferably contains 60% by mass or less of an ethylene-vinyl acetate copolymer.

  The ethylene-vinyl acetate copolymer preferably has a vinyl acetate content of 3 mol% to 50 mol%. When the vinyl acetate content in the ethylene-vinyl acetate copolymer is 3 mol% or more, a sheet having excellent flexibility can be obtained. Further, when the content of vinyl acetate is 50 mol% or less, even when the waterproof sheet is stored in an environment of 30 ° C. or higher, the water-impervious sheets do not stick together and are not integrated (blocked). Or less. From the viewpoint of obtaining such effects more remarkably, the vinyl acetate content is more preferably 5 mol% to 40 mol%, and still more preferably 10 mol% to 30 mol%.

  The ethylene-vinyl acetate copolymer preferably has a melt flow rate at 230 ° C. (hereinafter, “melt flow rate” is also referred to as “MFR”) of 1 g / 10 min to 15 g / 10 min. When the MFR of the ethylene-vinyl acetate copolymer is 1 g / 10 min or more, the resin component is liable to flow during thermal bonding and easily entangled with the nonwoven fabric, and the adhesion between the nonwoven fabric and the water shielding sheet is further improved. Moreover, when producing a water shielding sheet, it is easy to form a pool of liquid (generally also referred to as a bank) between metal rolls, and it is easy to produce without causing bank breakage. When the MFR of the ethylene-vinyl acetate copolymer is 10 g / 10 min or less, the resin component flows too much into the nonwoven fabric during thermal bonding, and the strength of the water shielding sheet is less likely to decrease. From the viewpoint of obtaining such effects more remarkably, the MFR of the ethylene-vinyl acetate copolymer is more preferably 1.5 g / 10 min to 10 g / 10 min.

  The water shielding sheet needs to contain 20% by mass to 80% by mass of polyethylene. When the polyethylene content in the water-impervious sheet is 20% by mass or more, a water-impervious sheet excellent in adhesive strength with the nonwoven fabric can be obtained. The waterproof sheet firmly bonded to the nonwoven fabric has a high adhesive force between the nonwoven fabric and the waterproof sheet, and the nonwoven fabric and the waterproof sheet are not peeled off during or after the waterproof sheet is applied. Moreover, as will be described later, it is possible to obtain a waterproof sheet having a configuration in which a nonwoven fabric and a water-impervious sheet are bonded to each other in a dotted or linear manner. From the viewpoint of more prominently obtaining such effects, the water shielding sheet preferably contains 40% by mass or more of polyethylene. Moreover, the above-mentioned ethylene-vinyl acetate copolymer can fully be contained as content of the polyethylene in a water shielding sheet is 80 mass% or less. Moreover, when there is too much content of polyethylene, the softness | flexibility and tensile strength of a water-impervious sheet may fall. From the viewpoint of more prominently obtaining such effects, the water shielding sheet preferably contains 60% by mass or less of polyethylene.

  The reason why the water shielding sheet containing 20% by mass or more of polyethylene is excellent in adhesive strength with the nonwoven fabric is not clear, but polyethylene is probably resistant to acids and alkalis, and is not suitable for ordinary organic solvents such as methanol, ethanol, acetone, methyl ethyl ketone, etc. Since the water-shielding sheet is difficult to deteriorate due to the organic solvent contained in the adhesive when it is bonded with an adhesive, the interface between the water-shielding sheet and the adhesive is difficult to peel off, and the adhesive strength Is expected to improve. In addition, when heat-bonded, the polyethylene is easy to soften and adhere, and the strength after curing is high, so at the interface between the water-impervious sheet and the nonwoven fabric, a part of the fibers constituting the nonwoven fabric is taken into the surface of the water-impervious sheet. However, it is expected that the adhesive force will be improved by the anchor effect.

  Moreover, the water-impervious sheet can reduce changes in physical properties due to temperature by including polyethylene. The ethylene-vinyl acetate copolymer tends to change in physical properties and adhesiveness due to changes in temperature environment due to its resin characteristics. In the present invention, a change in physical properties due to a change in temperature environment can be suppressed by mixing polyethylene with an ethylene-vinyl acetate copolymer.

  Polyethylene can be used by selecting one or more from high density polyethylene, low density polyethylene, and linear low density polyethylene. When high density polyethylene is used, a water shielding sheet excellent in impact resistance can be obtained due to its resin characteristics. Moreover, when low density polyethylene is used, a water shielding sheet excellent in heat weldability can be obtained due to its resin characteristics.

  Especially, it is preferable that polyethylene is a linear low density polyethylene. The water shielding sheet containing linear low density polyethylene has particularly excellent tensile strength. If the water shielding sheet is excellent in tensile strength, the water shielding sheet is difficult to break. For example, when used in a tunnel, spring water does not move from the breakage portion of the water-impervious sheet to the secondary lining concrete, or less, so that cracking is less likely to occur in the secondary lining concrete. Or if it uses for the embankment construction method of a natural mountain slope, since the spring water does not transfer to the embankment side from the fracture | rupture part of a water-impervious sheet, or less, a embankment collapses and a paved road etc. are hard to collapse.

  The linear low density polyethylene may be produced by copolymerizing 1 to 10% by mass of an α-olefin with ethylene as a repeating unit. The linear low density polyethylene thus produced may contain an α-olefin such as 1-butene, 1-hexane, 4-methylpentene-1, 1-octene in the component. The α-olefin may be contained in the low density polyethylene component in a range of less than 10% by mass, or may be contained in a component constituting the water shielding sheet in a range of less than 8% by mass.

Linear low density polyethylene is preferably a density of ^{0.86g / cm 3 ~0.93g / cm 3} . A linear low density polyethylene having such a density is low in price and excellent in processability.

  Polyethylene preferably has a melt flow rate at 230 ° C. of 1 g / 10 min to 10 g / 10 min. When the MFR of polyethylene is 1 g / 10 min or more, the resin component easily flows during thermal bonding and becomes easily entangled with the nonwoven fabric, so that the adhesion between the nonwoven fabric and the water shielding sheet is further improved. Moreover, when producing a water shielding sheet, it is easy to form a pool of liquid (generally also referred to as a bank) between metal rolls, and it is easy to produce without causing bank breakage. When the MFR of polyethylene is 10 g / 10 min or less, there is little or no risk that the resin component flows too much into the nonwoven fabric during thermal bonding, and the strength of the water shielding sheet is reduced. From the viewpoint of obtaining such effects more remarkably, the MFR of polyethylene is more preferably 1.5 g / 10 min to 7 g / 10 min.

  The water-impervious sheet may contain other resin components in an amount of 30% by mass or less in addition to the ethylene-vinyl acetate copolymer and polyethylene. More preferably, it is the range of 10 mass% or less. Other resins are not particularly limited, and for example, polyolefin resins such as polypropylene, polybutene, ethylene-propylene copolymer, and ethylene-vinyl alcohol copolymer can be used. Moreover, the water shielding sheet may contain an antioxidant, a heat stabilizer, and the like in an amount of less than 10% by mass as necessary.

  The water shielding sheet preferably has a thickness of 0.1 mm to 3 mm, and more preferably 0.3 mm to 2 mm. If the thickness of the water-impervious sheet is 0.1 mm to 3 mm, the waterproof sheet is excellent in handleability during construction. The thickness of the water shielding sheet is measured according to JIS K 6250 8.1 (A method).

The water shielding sheet preferably has a tensile strength at 20 ° C. measured in accordance with JIS K 6773 of 12 N / mm ² or more, and more preferably 15 N / mm ² or more. When the tensile strength is 10 N / mm ² or more, the water shielding sheet is hardly broken. The upper limit with preferable tensile strength is 100 N / mm < ² >.

  The water shielding sheet preferably has an elongation at 20 ° C. of 500% or more, more preferably 600% or more, measured according to JIS K 6773. When the elongation is 500% or more, it becomes easy to construct the waterproof sheet along the arcuate surface of the tunnel or the curved slope of the natural ground. A preferable upper limit of elongation is 1000%.

  The water shielding sheet preferably has a tear strength measured according to JIS K 6301 of 400 N / cm or more, and more preferably 500 N / cm or more. When the tear strength is 400 N / cm or more, the water shielding sheet is difficult to tear. A preferable upper limit of the tear strength is 2000 N / cm.

(Sheet network)
In the waterproof sheet of the present invention, it is preferable that a sheet-like net formed by irregularly intersecting a plurality of continuous filaments having a thickness of 0.1 mm to 10 mm is integrated with the other surface of the nonwoven fabric. In addition, the other surface of a nonwoven fabric means the surface in which the water-proof sheet | seat is not adhere | attached in a nonwoven fabric.

  When the sheet-like net is integrated with the other surface of the nonwoven fabric, the sheet-like net functions as a water conduit for draining spring water and the like to the outside. The waterway constructed of a sheet-like net is not easily deformed in the thickness direction even when pressure is applied to the waterproof sheet due to the placement of concrete or the weight of the embankment, etc. A larger amount of spring water can be drained. For example, when a waterproof sheet is stretched between a primary lining concrete and a secondary lining concrete in a tunnel construction with a sheet-like network placed on the primary lining concrete side, the spring generated from the primary lining concrete side In addition to the space between the nonwoven fabric and the water-impervious sheet, water and the like pass through the voids of the sheet-like net and are discharged to the outside.

  A part or all of the sheet-like net-like body can be used by being embedded in the primary lining concrete or the ground surface. When at least a part of the sheet-like net is embedded in the primary lining concrete or the ground surface, the sheet-like network functions as an anchor material, so that the concrete, the ground, and the waterproof sheet are difficult to peel off or peel off. When a part of the sheet network is embedded in the primary lining concrete, the sheet network that is not embedded in the concrete functions as a water conduit. Moreover, when embedding the whole sheet-like net-like body in primary lining concrete, between a nonwoven fabric and a water-impervious sheet functions as a water conduit.

  The thickness (diameter) of the continuous filament is preferably 0.1 mm to 10 mm, more preferably 0.3 mm to 5 mm, and even more preferably 0.5 mm to 3 mm. When the thickness of the continuous filament is 0.1 mm or more, the filament is difficult to break. Further, when the thickness of the continuous filament is 10 mm or less, the continuous intersections between the continuous filaments and the continuous filament and the nonwoven fabric do not become too large, and the network forms an appropriate gap. In addition, the thickness of a continuous filament measures the diameter in 100 arbitrary places of a continuous filament, and makes the average value the thickness of a continuous filament.

  The cross-sectional shape of the continuous filament is not particularly limited, and may be any shape such as a circle, an ellipse, a triangle, a quadrangle, a polygon, a Y shape, and a cross shape. When the filament cross section has a shape other than a circular shape, the thickness of the continuous filament is the diameter of the circle when the filament cross section is measured and converted to a circle having the same area as the cross section.

  The sheet-like net is preferably composed of continuous filaments. When the filament is continuous, the filament tip is less than the case where the filament is discontinuous, and the filament tip does not damage the water shielding sheet or less.

  The component constituting the continuous filament is not particularly limited, but is a synthetic resin such as a polyolefin resin such as polyethylene, polypropylene or polybutene, a polyester resin such as polyethylene terephthalate or polybutylene terephthalate, or a polyamide resin such as nylon 6 or nylon 66. Good. Among these, a polyolefin resin is preferable from the viewpoint of excellent alkali resistance and weather resistance. When the continuous filament is made of a polyolefin resin, a network having excellent alkali resistance is obtained. For example, even when an alkaline solution is generated from the cast concrete, the sheet network is hardly deteriorated.

Sheet mesh body is preferably sized mesh cells viewed mesh body from a direction perpendicular to the surface is 1mm ² ~1000mm ^2. When the mesh size is 1 mm ² or more, even when a large amount of spring water is generated, clogging is unlikely to occur and it can be discharged. Moreover, when the mesh size is 1000 mm ² or less, when the mesh body side of the waterproof sheet is stretched on the primary lining concrete, the nonwoven fabric and the primary lining concrete are in close contact with each other at the mesh portion and the spring water passes through. Is less or less. From the viewpoint of obtaining such an effect more remarkably, it is preferable size of the mesh viewed from a direction perpendicular to the sheet is 10 mm ² 500 mm ^2.

The mesh size of the sheet-like network is measured according to the following procedure. A sample having a width of 100 mm × a length of 100 mm is prepared from a sheet-like mesh, and the size S of all meshes surrounded by continuous filaments existing in the sample is measured when the sample is viewed from the direction perpendicular to the surface. A value obtained by dividing the sum of S ^{2 by} the sum of S, that is, a value calculated by the following equation.
(S ₁ ² + S ₂ ² + S ₃ ² ... + S _n ² ) / (S ₁ + S ₂ + S ₃ ... + S _n )

  The mesh of the sheet network is formed by irregularly intersecting a plurality of continuous filaments. In the present invention, among the meshes of the sheet-like network, the mesh having a larger mesh size greatly influences the above-described large-scale drainage effect of the spring water. ) Is defined as the mesh size.

  It is preferable that the contact point and intersection of continuous filaments are adhere | attached on a sheet-like net-like body. When the contacts and intersections of continuous filaments are bonded, the network structure is not easily crushed even if pressure is applied to the waterproof sheet by placing concrete. Moreover, it is more preferable that the contact points and intersections between the continuous filaments are bonded by components constituting the continuous filament. If continuous filaments are bonded to each other by the components that make up the continuous filaments, there will be no protruding bonding points due to adhesives etc. at the bonding intersections, so even if the waterproof sheet is wound into a roll, the waterproof sheet will be scratched. There is nothing.

  The sheet network is preferably 1 mm to 30 mm in thickness. When the thickness of the net-like body is 1 mm or more, even when earth and sand are contained in the spring water, clogging does not occur and good water permeability can be obtained. Further, when the thickness of the net-like body is 30 mm or less, the nonwoven fabric and the net-like body are difficult to peel off. From the viewpoint of obtaining such effects more remarkably, the thickness of the sheet-like network is preferably 2 mm to 10 mm. Moreover, the sheet-like net may have a convex part or a concave part in the thickness direction.

As for the thickness of the sheet-like network, the sheet-like network was sandwiched between ^two acrylic plates having a thickness of 3 mm with the sheet-like network peeled off from the waterproof sheet, and a load of 2.94 cN per cm ² was applied. In the state, the distance between the acrylic plates is measured to obtain the thickness of the sheet-like network.

Sheet meshwork is preferably basis weight is ^{80g / m 2 ~1000g / m 2} . If the basis weight is 80 g / m ² or more, it is easy to form a gap serving as a water conduit. In addition, when the basis weight is 1000 g / m ² or less, it does not become too heavy and, for example, it can be easily placed on a concrete surface. In particular, when the waterproof sheet of the present invention is installed inside the tunnel, the waterproof sheet is stretched against the gravity, and therefore, when the mass per unit area increases, it is difficult to place the sheet on the concrete surface. Tend to be. From the viewpoint of obtaining such an effect more remarkably, more preferably the basis weight of the sheet-like mesh body is ^{100g / m 2 ~500g / m 2} , further preferably ^{150g / m 2 ~400g / m 2} .

  The sheet network preferably has a porosity of 60% to 99.9%. When the porosity is 60% or more, the spring water can be drained without clogging even when the spring water contains solids such as earth and sand or particles. Further, when the porosity is 99.9% or less, the voids are not crushed due to concrete pouring pressure or embankment pressure.

The porosity of the sheet-like network is obtained by preparing a sample having a size of 10 cm × 10 cm from the sheet-like network, measuring the mass W (g) of the sample, and measuring the thickness T (cm) and the density of the constituent components described above. Using ρ (g / cm ³ ), the porosity is calculated by the following formula.
{1-W / (100 × T × ρ)} × 100 (%)

  The sheet-like network body preferably has irregularities in the thickness direction. The height of the convex portion is preferably 0.5 mm to 10 mm, and more preferably 1 mm to 7 mm. When the sheet-like network has irregularities in the thickness direction, the irregularities can be imparted to the surface of the nonwoven fabric facing the water-impervious sheet by pressurizing the sheet-like network and the nonwoven fabric with a metal roll or the like.

  The sheet-like net is particularly preferably bonded at the intersection of continuous filaments and has a thickness of 2 mm or more. With such a configuration, for example, in tunnel construction, a waterproof sheet is applied to the primary lining concrete surface from which steel fibers and rock bolts mixed with the primary lining concrete protrude, and the secondary lining concrete is cast from above. Even if it is installed, since the thickness of the mesh body is not reduced by the casting pressure of the secondary lining concrete, projections such as steel fibers and rock bolts can be taken into the voids of the mesh body Therefore, it can prevent that a water shielding sheet is damaged by a projection part.

(Waterproof sheet)
The waterproof sheet is formed by attaching a water shielding sheet to a surface of a nonwoven fabric in a dotted or linear manner. When the water-impervious sheet is bonded to one surface of the non-woven fabric in a dotted or linear manner, a large amount of spring water can be drained because the space between the nonwoven fabric and the water-impervious sheet functions as a water conduit. When a large amount of spring water is generated, a space is formed in an unbonded portion between the nonwoven fabric and the water-impervious sheet due to the water pressure, and this space becomes a water conduit and can be drained efficiently.

  The nonwoven fabric and the water shielding sheet may be joined via an adhesive, or may be heat-welded with components constituting the nonwoven fabric or the water shielding sheet. Especially, it is preferable that the nonwoven fabric and the water-impervious sheet are bonded by a hot melt adhesive or heat welding. With such a configuration, the organic solvent is not included, and the substance resulting from the organic solvent does not volatilize from the waterproof sheet.

  It is preferable that the adhesion interval of point adhesion or linear adhesion is 2 cm to 70 cm. Here, the adhesion interval means the distance between an arbitrary adhesion point and the closest other adhesion point in the case of dot adhesion, and in the case of linear adhesion, the direction perpendicular to the adhered linear portion. The distance to the other bonded linear part closest to. When the bonding interval is 2 cm or more, a space is easily formed in a non-bonded portion, and when the bonding interval is 70 cm or less, the nonwoven fabric and the water-impervious sheet are not easily displaced at the time of construction, and the construction is facilitated.

  Especially, it is more preferable that a nonwoven fabric and a water-shielding sheet are dot-bonded with a hot-melt adhesive, and an adhesion interval is 10 cm to 50 cm. With such a configuration, the nonwoven fabric and the water-impervious sheet are difficult to peel off, and an excellent water conduit can be formed between the nonwoven fabric and the water-impervious sheet.

If a point-like bonding the nonwoven fabric and the water-impervious sheet, the size of the adhesive portion is preferably 1 cm ² 100 cm ^2. A nonwoven fabric and a water shielding sheet can be firmly adhere | attached as the magnitude | size of an adhesion part is 1 cm < ² > or more. Moreover, when the magnitude | size of an adhesion part is 100 cm < ² > or less, an adhesion part hardly prevents the drainage between a nonwoven fabric and a water shielding sheet, and it becomes a waterproof sheet which drains more easily. From the viewpoint of obtaining such an effect more remarkably, the size of the adhesive portion is more preferably a 5 cm ² to 50 cm ^2.

  In the present invention, it is preferable to loosen and bond the non-woven fabric when performing point bonding or line bonding. Specifically, it is preferable to bond the nonwoven fabric with the bonding interval of 105% to 150% of the bonding interval of the water shielding sheet. For example, when the water shielding sheet is point-bonded at intervals of 30 cm, the nonwoven fabric may be point-bonded at intervals of 31.5 cm to 45 cm. A waterproof sheet obtained by loosening and bonding a nonwoven fabric is particularly suitable for a tunnel waterproof sheet.

  Usually, since the inner surface of the tunnel has an arc shape, the nonwoven fabric stretched further outside the arc tends to be pulled more than the water shielding sheet stretched further inside the arc. At this time, if the nonwoven fabric and the water shielding sheet are bonded to the entire surface or in the form of dots or lines having the same interval, they are dragged by the expansion of the water shielding sheet having a relatively high extensibility located inside the arc. In some cases, a nonwoven fabric having a relatively low extensibility located outside the arc may break. When the non-woven fabric and the water shielding sheet are bonded in a dotted or linear manner with the non-woven fabric bonding interval being 105% to 150% of the bonding interval of the water blocking sheet, even if a tensile force acts on the waterproof sheet, Since the tensile force acting on the nonwoven fabric outside the arc is relaxed due to the looseness caused by the difference, the nonwoven fabric is not broken or little.

  The waterproof sheet preferably has a peel strength between the nonwoven fabric and the water shielding sheet in a T-type peel test measured according to JIS K 6854-3, preferably 150N to 1000N, more preferably 180N to 600N. More preferably, it is 200N-400N. When the peel strength is 150 N, there is no peeling between the nonwoven fabric and the water-impervious sheet and the construction is easy. For example, in tunnel construction, even when a waterproof sheet is stretched near the ceiling surface, the nonwoven fabric and the water shielding sheet do not peel off. When the peel strength is 1000 N or less, the waterproof sheet and the nonwoven fabric are peeled off at the end joint of the waterproof sheet, and the waterproof sheet is interlaced and welded. The adhesive residue of the nonwoven fabric is less likely to remain on the surface.

  The waterproof sheet is preferably formed by integrating a sheet-like net on the other surface of the nonwoven fabric. The nonwoven fabric and the sheet-like network may be integrated with each other through an adhesive, or may be integrated with a component constituting a continuous filament. Especially, it is preferable that the nonwoven fabric and the sheet-like network are integrated by the component which comprises a continuous filament, and it is more preferable that the component which comprises a continuous filament is fuse | melted and integrated. When the nonwoven fabric and the net-like body are integrated by the components constituting the continuous filament, the nonwoven fabric and the net-like body are difficult to peel off. Moreover, a nonwoven fabric and a net-like body can be integrated more firmly by making a continuous filament into a film at an adhesion point.

  In the waterproof sheet, a nonwoven fabric may be further bonded to the surface of the water shielding sheet. With such a configuration, the adhesiveness with the secondary lining concrete can be improved, and the water shielding sheet can be prevented from being damaged when the secondary lining concrete is stretched. It becomes difficult to peel off. As the non-woven fabric adhered to the surface of the water-impervious sheet, the same fibers as those of the above-described non-woven fabric can be used.

The waterproof sheet preferably has a mass per unit area of 2 kg / m ² or less, and more preferably 1.5 kg / m ² or less. When the mass per unit area of the waterproof sheet is 2 kg / m ² or less, the waterproof sheet becomes light and the construction becomes easy. For example, construction is easy even when it is stretched on a tunnel ceiling or the like. Although not particularly limited, a preferable lower limit is 0.5 kg / m ² .

  The waterproof sheet of the present invention is particularly excellent as a waterproof sheet for tunnels. In the tunnel construction exclusively, a waterproof sheet is constructed on the inner surface of the tunnel, so that the waterproof sheet on the tunnel ceiling and the side surface of the tunnel receives a tensile force in the direction of the tunnel bottom due to its own weight and extension tension. Since the waterproof sheet of the present invention is excellent in the adhesive force between the nonwoven fabric and the waterproof sheet, the nonwoven sheet and the waterproof sheet are peeled off or the waterproof sheet is broken even if such tensile force acts on the waterproof sheet. Less is.

(Method for manufacturing waterproof sheet)
Below, an example of the manufacturing method of a waterproof sheet is shown.
First, an ethylene-vinyl acetate copolymer and polyethylene are melted and extruded from a T die to adjust the thickness between metal rolls to obtain a water shielding sheet. At this time, the ethylene-vinyl acetate copolymer and polyethylene may be mixed in advance to form a master batch. Furthermore, you may add additives, such as a hindered phenolic antioxidant, a phosphorus thermal stabilizer, and a hydroxyamine thermal stabilizer, as needed. Further, the water shielding sheet may be subjected to a stretching treatment as necessary.

  Next, a waterproof sheet in which the nonwoven fabric and the water shielding sheet are bonded in a dotted manner is obtained by adhering the adhesive to the water shielding sheet in the form of dots and pasting them together with the nonwoven fabric. Alternatively, by using a hot air welding machine or the like, the waterproof sheet surface is heated and melted linearly and bonded to the nonwoven fabric to obtain a waterproof sheet in which the nonwoven fabric and the waterproof sheet are linearly bonded. In addition, what is marketed may be used for a nonwoven fabric, and heat welding may be performed by irradiating a high frequency, an ultrasonic wave, infrared rays, a laser beam, etc.

  In addition, the waterproof sheet containing a sheet-like net-like body can also be obtained by integrating a sheet-like net-like body beforehand on one surface of a nonwoven fabric as needed. For example, the resin constituting the sheet-like net is heated to about 200 ° C. to 350 ° C. and melted, and this is extruded while rotating randomly from the spinning mold, and the continuous filaments irregularly intersecting the mold or By collecting on a collection plate to obtain a sheet-like network, and before the continuous filament is cured, the nonwoven fabric is overlaid and pressed with a metal roll, rubber roll, etc., and the nonwoven fabric and the sheet-like network Can be obtained. A waterproof sheet including a sheet-like network can be obtained by bonding an intermediate body in which a nonwoven fabric and a sheet-like network are integrated together with a water shielding sheet.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

(Tensile strength of waterproof sheet)
The tensile strength of the water shielding sheet was measured at a measurement temperature of 20 ° C. according to JIS K 6773.

(Elongation of water shielding sheet)
The elongation of the water shielding sheet was measured at a measurement temperature of 20 ° C. according to JIS K 6773.

(Tear strength of waterproof sheet)
The tear strength of the water shielding sheet was measured at a measurement temperature of 20 ° C. according to JIS K 6301.

(EVA resin 1)
As an ethylene-vinyl acetate copolymer, trade names: EV260, manufactured by Mitsui DuPont Polychemical Co., Ltd. were prepared. Hereinafter, this ethylene-vinyl acetate copolymer is also referred to as EVA resin 1.

(EVA resin 2)
As an ethylene-vinyl acetate copolymer, a trade name: P1405S, manufactured by Mitsui DuPont Polychemical Co., Ltd. was prepared. Hereinafter, this ethylene-vinyl acetate copolymer is also referred to as EVA resin 2.

(EVA resin 3)
As an ethylene-vinyl acetate copolymer, trade names: UE634, manufactured by USI Corporation were prepared. Hereinafter, this ethylene-vinyl acetate copolymer is also referred to as EVA resin 3.

(EVA resin 4)
As an ethylene-vinyl acetate copolymer, trade names: UE630, manufactured by USI CORPORATION, were prepared. Hereinafter, this ethylene-vinyl acetate copolymer is also referred to as EVA resin 4.

(EVA resin 5)
As an ethylene-vinyl acetate copolymer, trade names: E260F, manufactured by Samsun Total Co., Ltd. were prepared. Hereinafter, this ethylene-vinyl acetate copolymer is also referred to as EVA resin 5.

(LLDPE resin 1)
As the linear low density polyethylene, trade name: SP2040, manufactured by Prime Polymer Co., Ltd. was prepared. Hereinafter, this linear low density polyethylene is also referred to as LLDPE resin 1.

(LLDPE resin 2)
As linear low density polyethylene, the brand name: LL105, the product made from USI CORPORATION was prepared. Hereinafter, this linear low density polyethylene is also referred to as LLDPE resin 2.

(LLDPE resin 3)
As linear low density polyethylene, the brand name: LL120 and the product made from USI CORPORATION were prepared. Hereinafter, this linear low density polyethylene is also referred to as LLDPE resin 3.

  Table 1 shows the vinyl acetate content, density, melt flow rate at 230 ° C., and melting point of EVA resins 1 to 5 and LLDPE resins 1 to 3.

(Water shielding sheets 1 to 6)
EVA resin 1, EVA resin 2, and LLDPE resin 1 are mixed and melted at the resin ratios shown in Table 2, respectively, extruded from a T-die, and rolled to a predetermined thickness with a metal roll to obtain water shielding sheets 1 to 6 It was. Table 2 shows the thickness, tensile strength, elongation, tear strength, and specific gravity of the water shielding sheets 1 to 6.

(Water shielding sheet 7 to 10)
EVA resins 3 to 5 and LLDPE resins 1 and 2 are mixed and melted at the resin ratios shown in Table 3, respectively, extruded from a T-die, and rolled to a predetermined thickness with a metal roll to obtain water-impervious sheets 7 to 10. It was. Table 3 shows the thickness, tensile strength, elongation, tear strength, and specific gravity of the water shielding sheets 7 to 10.

Example 1
Polypropylene resin is heated and melted, the melt is spun from a spinneret in which a large number of spinning nozzles having a hole diameter of 1 mm are arranged, and a continuous filament is placed on a mold having a 5 mm high projection provided below the spinneret The mold was moved while hanging down to obtain a sheet-like net. The sheet-like net had a continuous filament thickness of 1 mm, a thickness of 5 mm, a basis weight of 250 g / m ² , and a mesh size of 140 mm ² .

  Next, a spunbond nonwoven fabric made of polypropylene fibers and having a thickness of 0.5 mm is prepared. Before the continuous filaments constituting the sheet network are completely solidified, the nonwoven fabric is pressed from above the sheet network and applied. The intermediate body in which the nonwoven fabric and the sheet-like network were integrated by continuous filaments and the nonwoven fabric and the on-sheet network were laminated and integrated was produced.

  Subsequently, a hot melt adhesive made of an ethylene-vinyl acetate copolymer is dotted on the surface of the water-proof sheet 1 at intervals of 40 cm in the width direction (CD direction) of the waterproof sheet. The waterproof sheet of Example 1 was obtained by adhering to the non-woven fabric surface of the intermediate body in which the non-woven fabric and the mesh on the sheet were laminated and integrated.

(Example 2)
A waterproof sheet of Example 2 was obtained in accordance with the procedure adopted in Example 1, except that the water shielding sheet 2 was used instead of the water shielding sheet 1.

(Example 3)
A waterproof sheet of Example 3 was obtained in accordance with the procedure employed in Example 1, except that the water shielding sheet 3 was used instead of the water shielding sheet 1.

Example 4
A waterproof sheet of Example 4 was obtained in accordance with the procedure employed in Example 1, except that the water shielding sheet 4 was used instead of the water shielding sheet 1.

(Example 5)
A waterproof sheet of Example 5 was obtained in accordance with the procedure adopted in Example 1, except that the water shielding sheet 5 was used instead of the water shielding sheet 1.

(Comparative Example 1)
A waterproof sheet of Comparative Example 1 was obtained in accordance with the procedure adopted in Example 1 except that the water shielding sheet 6 was used instead of the water shielding sheet 1.

(Example 6)
A waterproof sheet of Example 6 was obtained in accordance with the procedure adopted in Example 1, except that the water shielding sheet 7 was used instead of the water shielding sheet 1.

(Example 7)
A waterproof sheet of Example 7 was obtained in accordance with the procedure employed in Example 1, except that the water shielding sheet 8 was used instead of the water shielding sheet 1.

(Example 8)
A waterproof sheet of Example 8 was obtained in accordance with the procedure adopted in Example 1 except that the water shield sheet 9 was used instead of the water shield sheet 1.

Example 9
A waterproof sheet of Example 9 was obtained in accordance with the procedure employed in Example 1, except that the water shielding sheet 10 was used instead of the water shielding sheet 1.

(Example 10)
A hot-melt adhesive made of an ethylene-vinyl acetate copolymer is dotted on the surface of a spunbonded nonwoven fabric made of polypropylene fiber and having a thickness of 0.5 mm, at intervals of 40 cm in the width direction (CD direction) of the waterproof sheet, The waterproof sheet of Example 10 was obtained by adhering the nonwoven fabric and the water shielding sheet 3 by attaching them at 30 cm intervals in the length direction (MD direction) of the waterproof sheet. The peel strength of this waterproof sheet is 229N between the nonwoven fabric and the water shielding sheet in the T-shaped peel test measured according to JIS K 6854-3, and the nonwoven fabric and the water shield sheet are firmly bonded. It was.

  In the waterproof sheets of Examples 1 to 9, the nonwoven fabric and the water shielding sheet were firmly bonded. In the waterproof sheet of Comparative Example 1, the nonwoven fabric and the water shielding sheet were weak and easily peeled off.

  Since the water-impervious sheets 1 to 5 and the water-impervious sheets 7 to 10 contain linear low-density polyethylene, they were water-impervious sheets having higher tensile strength than Comparative Example 6. Especially, since the water shielding sheets 3-5 contained 40 mass% or more of linear low density polyethylene, the very outstanding tensile strength was shown. Moreover, since the water shielding sheets 1 and 4 contained 50% by mass of the EVA resin 1 and the LLDPE resin, they exhibited excellent elongation.

  In the waterproof sheet of the present invention, since the non-woven fabric and the water-impervious sheet are bonded in the form of dots or lines, the space between the non-woven fabric and the water-impervious sheet functions as a water conduit, so spring water from the ground or the ground, etc. It is preferably used when constructing a tunnel or a paved road in a place where the above occurs. For example, it can be used for the new Austrian tunnel method (NATM method), the lightweight embankment method and the like. Especially, since the waterproof sheet of the present invention is excellent in the adhesive force between the nonwoven fabric and the water shielding sheet, even if the waterproof sheet is stretched on the arc surface inside the tunnel, the water shielding sheet does not break due to tensile force or the like. Therefore, it is particularly suitable as a waterproof sheet for tunnels.

DESCRIPTION OF SYMBOLS 1 Water-blocking sheet 2 Nonwoven fabric 3 Sheet-like network 10 Waterproof sheet 20 Continuous filament 22 Mesh 30 Ground mountain 32 Rock bolt 34 Primary lining concrete 36 Secondary lining concrete 38 Space in tunnel

Claims (7)

A waterproof sheet in which a water shielding sheet is bonded to one surface of the nonwoven fabric,
The water shielding sheet contains 20% by mass to 80% by mass of an ethylene-vinyl acetate copolymer, 20% by mass to 80% by mass of polyethylene,
The waterproof sheet, wherein the non-woven fabric and the water-proof sheet are bonded to each other in a dotted or linear manner.   The waterproof sheet according to claim 1, wherein the polyethylene is linear low-density polyethylene.   The waterproof sheet according to claim 1 or 2, wherein the non-woven fabric and the water shielding sheet are bonded in a point-like manner with a hot melt adhesive, and an adhesion interval is 10 cm to 50 cm. Waterproof sheet according to the size of the bonded portion between the water shield sheet and the nonwoven fabric, any one of claims 1 to 3 is 5 cm ² to 50 cm ^2.   The waterproof sheet according to any one of claims 1 to 4, wherein an adhesion interval of the nonwoven fabric is 105% to 150% of an adhesion interval of the water shielding sheet.   The sheet-like net body formed by integrating a plurality of continuous filaments having a thickness of 0.1 mm to 10 mm irregularly on the other surface of the nonwoven fabric is integrated. The specified tarpaulin.   The waterproof sheet for tunnels according to any one of claims 1 to 6.

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