Technical Field

The present invention relates to a waterproof sheet for an asphalt-paved road, a waterproof structure, and a method for constructing a waterproof structure.

Background

On an asphalt-paved road such as a bridge, the asphalt deteriorates due to the infiltration of water such as rain water, which may cause cracking. Therefore, various waterproof structures and construction methods thereof have been proposed.

For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2003-313817A) discloses a method of forming a urethane-based waterproof material layer on a concrete slab and, after the urethane-based waterproof material layer cures, laminating a thermoplastic resin and asphalt pavement thereon.

Brief Summary

In the repair or the like of a road involving traffic regulations, there is a demand for the shortening of construction time . However, in the method described in Patent Document 1, it is necessary to apply and cure the urethane-based waterproof material layer at the construction site, which is problematic in that curing and construction take time.

One aspect of the present invention relates to a waterproof sheet for an asphalt-paved road comprising: a waterproof layer containing a thermoplastic urethane resin; a fusing layer provided on one face of the waterproof layer, the fusing layer containing a thermoplastic resin having a melt temperature of not more than 100°C; an adhesive agent layer provided on another face of the waterproof layer, the adhesive agent layer containing an adhesive agent; and a bonding layer provided between the waterproof layer and the fusing layer so as to bond the waterproof layer and the fusing layer.

Another aspect of the present invention relates to a waterproof structure comprising the waterproof sheet described above and asphalt pavement laid on the fusing layer of the waterproof sheet.

Yet another aspect of the present invention relates to a method for constructing a waterproof structure comprising the steps of: disposing the waterproof sheet described above so that the adhesive agent layer is on a construction face side; and laying asphalt pavement on the fusing layer of the waterproof sheet.

The present invention provides a waterproof sheet for an asphalt-paved road which makes it possible to easily construct a waterproof structure having excellent durability in a short amount of time. In addition, the present invention provides a waterproof structure comprising a waterproof sheet for an asphalt-paved road and having excellent durability. Further, the present invention provides a method for constructing a waterproof structure which makes it possible to easily form a waterproof structure with a short construction time .

Brief Description of Drawing

FIG. 1 is a cross-sectional view illustrating an overview of the waterproof sheet for an asphalt-paved road according to an embodiment.

FIG. 2 is a cross-sectional view illustrating an overview of a waterproof structure according to an embodiment.

FIGS . 3A to 3 C are drawings for explaining the method for constructing the waterproof structure according to an embodiment.

FIG. 4 is a drawing for explaining an evaluation method in a tension test.

Detailed Description of Embodiments

A preferred embodiment of the present invention will be described hereinafter with reference to the drawings. Note that portions of the drawings are drawn with exaggerated size for the sake of convenience, but such drawings should not be construed to be indications of the actual dimensions of the constituents.

Waterproof sheet

FIG. 1 is a cross-sectional view illustrating an overview of the waterproof sheet for an asphalt-paved road (also called a "waterproof sheet" hereafter) according to an embodiment. A waterproof sheet 10 comprises: a waterproof layer 1 containing a thermoplastic urethane resin; a fusing layer 2 provided on one face of the waterproof layer 1 , the fusing layer 2 containing a thermoplastic resin having a melt temperature of not more than 100°C; an adhesive agent layer 3 provided on another face of the waterproof layer 1 , the adhesive agent layer 3 containing an adhesive agent; and a bonding layer 4 provided between the waterproof layer 1 and the fusing layer 2 so as to bond the waterproof layer 1 and the fusing layer 2.

Since the waterproof sheet 10 is a sheet in which the waterproof layer 1 , the fusing layer 2, the adhesive agent layer 3, and the bonding layer 4 are formed integrally, using the waterproof sheet 10 makes it possible to form a waterproof structure more easily and in a shorter amount of time than in a conventional construction method. In addition, since the waterproof sheet 10 includes a bonding layer 4 for bonding the waterproof layer 1 and the fusing layer 2 between the waterproof layer 1 and the fusing layer 2, delamination between the waterproof layer 1 and the fusing layer 2 is suppressed, and a waterproof structure having excellent durability can be achieved.

The waterproof layer 1 is a layer which contributes to the water resistance of the waterproof structure . The waterproof layer 1 contains a thermoplastic urethane resin. A thermoplastic urethane resin is a thermoplastic resin having a plurality of urethane bonds (- NHCOO-) in the molecule . Examples of thermoplastic urethane resins include polyether-based urethane resins, polyester-based urethane resins, polycarbonate-based urethane resins, adipate- based urethane resins, and caprolactone-based urethane resins. The waterproof layer 1 may contain one type or two or more types of thermoplastic urethane resins .

The weight average molecular weight of the thermoplastic urethane resin may be, for example, not less than 30,000 or not less than 50,000. In addition, the weight average molecular weight of the thermoplastic urethane resin may be, for example, not more than 300,000 or not more than 200,000. Note that in this specification, the weight average molecular weight of the thermoplastic urethane resin refers to a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene .

The flow starting temperature of the thermoplastic urethane resin may be, for example, not less than 100°C or not less than 140°C. As a result, the tearing of the waterproof layer 1 due to heating at the time of the laying of the asphalt pavement is sufficiently prevented. The flow starting temperature of the thermoplastic urethane resin may be, for example, not more than 240°C or not more than 200°C. Note that in this specification, the flow starting temperature of the thermoplastic urethane resin refers to a value measured with a Koka-type flow tester method (die : 1 mm x 1 mm φ, load: 294 N, starting temperature : 1 10°C) .

The waterproof layer 1 may contain components other than the thermoplastic urethane resin. Examples of components other than the thermoplastic urethane resin include polyolefin- based resins, polyester-based resins, polyamide-based resins, and styrene-based elastomers.

The waterproof layer 1 may be a layer containing the thermoplastic urethane resin as a main component or may be a layer consisting of the thermoplastic urethane resin. The content of the thermoplastic urethane resin in the waterproof layer 1 may be, for example, not less than 60 mass% on the basis of the total amount of the waterproof layer 1 , and is preferably not less than 80 mass% and more preferably not less than 90 mass%.

The thickness of the waterproof layer 1 may be, for example, not less than 0.05 mm, and is preferably not less than 0. 1 mm and more preferably not less than 0.2 mm. This yields an effect that the durability of the waterproof structure is even more superior. Specifically, this yields the effect of having excellent penetration resistance as defined in Waterproof Test II of the Structure-Related Test Method of the NEXCO Test Method (4th Edition) (July 2015). The thickness of the waterproof layer 1 may be, for example, not more than 5 mm, and is preferably not more than 3 mm and more preferably not more than 2 mm. This yields the effect of having excellent handleability at the time of construction in that the weight of the roll does not become too large when the waterproof sheet is formed into a roll shape, the roll length of the roll can be increased, and the like .

The flow starting temperature of the waterproof layer 1 - that is, the flow starting temperature of the resin composition constituting the waterproof layer 1 - may be, for example, not less than 100°C and is preferably not less than 140°C. As a result, the tearing of the waterproof layer 1 due to heating at the time of the laying of the asphalt pavement is sufficiently prevented. The flow starting temperature of the waterproof layer 1 may be, for example, not more than 240°C or not more than 200°C. Note that in this specification, the flow starting temperature of the waterproof layer 1 refers to a value measured with a Koka-type flow tester method (die: 1 mm x 1 mm φ, load: 294 N, starting temperature: 110°C).

The fusing layer 2 is a layer for fusing the asphalt pavement at the time of the

construction of the waterproof structure, and the fusing layer 2 contains a thermoplastic resin having a melt temperature of not more than 100°C (also called a "thermoplastic resin A" hereafter).

The melt temperature of the thermoplastic resin A is preferably not more than 100°C and more preferably not more than 80°C. When the melt temperature of the thermoplastic resin A is not more than 100°C, the fusibility of the fusing layer 2 and the asphalt pavement is further enhanced. In addition, even when a waterproof structure is constructed in the winter, sufficient bond strength can be achieved with the asphalt pavement.

The melt temperature of the thermoplastic resin A may be, for example, not less than

30°C, and is preferably not less than 35°C and more preferably not less than 50°C. When the melt temperature of the thermoplastic resin A is not less than 30°C, it is possible to sufficiently prevent rutting from occurring in the asphalt pavement due to wheel load associated with vehicle traffic.

Note that in this specification, the melt temperature of the thermoplastic resin A refers to a value measured with the method according to JIS K6924-2 ( 1997).

From the perspective of being able to maintain sufficient bonding after fusing with the asphalt pavement, the thermoplastic resin A may be at least one type of resin selected from the group consisting of polyolefin-based resins, polyester-based resins, polyamide-based resins, and polyurethane-based resins, for example. More specifically, the thermoplastic resin A may be at least one type of resin selected from a group consisting of ethylene-vinyl acetate copolymers (EVA), ionomers, ethylene acrylic copolymers (EAA), and styrene butylene elastomers (SBS). The thermoplastic resin A is preferably an elastomer having water resistance from the perspective of the waterproof structure having even better durability. The thermoplastic resin A is more preferably an ethylene-vinyl acetate copolymer (EVA) from the perspective of having excellent bonding with the asphalt pavement. The fusing layer 2 may contain one type or two or more types of thermoplastic resins A.

The weight average molecular weight of the thermoplastic resin A may be, for example, not less than 10,000 or not less than 40,000, for example. In addition, the weight average molecular weight of the thermoplastic resin A may be, for example, not more than 100,000 or not more than 60,000. Note that in this specification, the weight average molecular weight of the thermoplastic resin A refers to a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

The fusing layer 2 may contain components other than the thermoplastic resin A.

Examples of components other than the thermoplastic resin A include reinforcing members such as fillers and nonwoven fabrics, antioxidants, light-resistant materials, deterioration inhibitors, and the like .

The fusing layer 2 may be a layer containing the thermoplastic resin A as a main component or a layer consisting of the thermoplastic resin A. The content of the thermoplastic resin A in the fusing layer 2 may be, for example, not less than 60 mass% on the basis of the total amount of the fusing layer 2, and is preferably not less than 80 mass% and more preferably not less than 90 mass%.

The thickness of the fusing layer 2 may be, for example, not less than 0. 1 mm, and is preferably not less than 0.2 mm and more preferably not less than 0.5 mm. This yields the effect of having excellent fusibility with the asphalt. The thickness of the fusing layer 2 may be, for example, not more than 10 mm, and is preferably not more than 5 mm and more preferably not more than 2 mm. This yields the effect of having excellent handleability at the time of construction in that the weight of the roll does not become too large when the waterproof sheet is formed into a roll shape, the roll length of the roll can be increased, and the like .

The melt temperature of the fusing layer 2 - that is, the melt temperature of the resin composition constituting the fusing layer 2 - may be, for example, not more than 80°C and is preferably not more than 70°C. As a result, the fusibility at the time of the laying of the asphalt pavement is further enhanced. The melt temperature of the fusing layer 2 may be, for example, not less than 30°C or not less than 40°C. This makes it possible to sufficiently prevent rutting from occurring in the asphalt pavement due to wheel load associated with vehicle traffic. Note that in this specification, the melt temperature of the fusing layer 2 refers to a value measured with the method according to JIS K6924-2 ( 1997).

The adhesive agent layer 3 is a layer for bonding the construction face and the waterproof layer 1 , and the adhesive agent layer 3 contains an adhesive agent. The adhesive agent is at least one type of adhesive agent selected from the group consisting of solvent-type acrylic-based adhesive agents, solvent-type natural rubber-based adhesive agents, emulsion-type acrylic-based adhesive agents, and hot melt-type acrylic-based adhesive agents. Acrylic-based adhesive agents are preferable from the perspective of the waterproof structure having even better durability. In this embodiment, an acrylic-based adhesive tape may be used as the adhesive agent layer 3. The adhesive agent layer 3 may contain one type or two or more types of adhesive agents.

The adhesive agent layer 3 is preferably a foam body. In this case, the durability of the waterproof structure tends to be further enhanced. The reason that such an effect is achieved is unclear, but the present inventors surmise the following . Typically, the construction face to be paved with asphalt (asphalt pavement) (for example, a concrete slab) has unevenness and cracks on the surface, so gaps are sometimes formed between the waterproof sheet 10 and the construction face . In this case, steam from the slab face accumulates in the gaps, which may lead to problems such as the gradual peeling of the waterproof sheet 10. On the other hand, when the adhesive agent layer 3 is a foam body, the adhesive agent layer 3 has excellent following characteristics with respect to the unevenness and cracks of the construction face, so the generation of such gaps is easily prevented. In addition, the adhesion with the construction face is easily enhanced as a result of an increase in the contact area between the construction face and the adhesive agent layer 3. It is presumed to be due to these reasons that the durability of the waterproof structure is further enhanced when the adhesive agent layer 3 is a foam body.

Note that the statement that the "adhesive agent layer 3 is a foam body" means that at least a portion of the adhesive agent layer 3 is a foam body.

The adhesive agent layer 3 is not limited to a single layer as long as it is a layer containing an adhesive agent on the surface on the waterproof layer 1 side and the surface on the opposite side as the waterproof layer 1. The adhesive agent layer 3 may be, for example, a layer comprising a base layer and layers containing an adhesive agent on both sides of the base layer. From such a perspective, the adhesive agent layer 3 may be a double-sided adhesive tape .

The thickness of the adhesive agent layer 3 may be, for example, not less than 0. 1 mm, and is preferably not less than 0.5 mm and more preferably not less than 1.0 mm. This yields the effect of having excellent bonding with the underlying layer. The thickness of the adhesive agent layer 3 may be, for example, not more than 10 mm, and is preferably not more than 5 mm and more preferably not more than 2 mm. This yields the effect of having excellent handleability at the time of construction in that the weight of the roll does not become too large when the waterproof sheet is formed into a roll shape, the roll length of the roll can be increased, and the like.

The bonding layer 4 is a layer for bonding the waterproof layer 1 and the fusing layer 2.

The bonding layer 4 may be, for example, a layer derived from a primer applied to the waterproof layer 1 or the fusing layer 2. The primer may be selected appropriately in accordance with the compositions of the waterproof layer 1 and the fusing layer 2.

The primer may be, for example, a primer containing a compound having an isocyanate group. Since such a primer has excellent reactivity with the thermoplastic urethane resin of the waterproof layer 1 , excellent bonding strength can be achieved between the waterproof layer 1 and the fusing layer 2. The primer preferably further contains a chlorinated polyolefin.

A commercially available primer may be used as the primer. Examples of commercially available primers include K-500NT, K-500, K-550, V-720, V-700, C- 100, and N-200 (all manufactured by 3M Ltd.) .

The bonding layer 4 may be a layer containing an adhesive resin composition. The adhesive resin composition may be, for example, a resin composition containing a thermoplastic resin and a tackifier. Such a bonding layer 4 may be interposed between the waterproof layer 1 and the fusing layer 2 when the waterproof layer 1 and the fusing layer 2 are laminated or may be formed by extrusion molding together with the waterproof layer 1 and the fusing layer 2.

The thermoplastic resin contained in the adhesive resin composition may be, for example, modified EVA or the like .

Examples of tackifiers include rosin-based, terpene-based, synthetic petroleum-based, phenolic resin-based, and xylene resin-based tackifiers . When the bonding layer 4 is a primer, the thickness of the bonding layer 4 may be, for example, not less than 0.0001 mm, and is preferably not less than 0.0005 mm and more preferably not less than 0.001 mm. This yields an effect that the interlayer bonding between the waterproof layer 1 and the fusing layer 2 is even more superior. The thickness of the bonding layer 4 is, for example, not more than 0. 1 mm, and is preferably not more than 0.05 mm and more preferably not more than 0.02 mm. As a result, the cohesive force of the primer layer is kept strong.

When the bonding layer 4 is an adhesive resin composition, the thickness of the bonding layer 4 may be, for example, not less than 0.01 mm, and is preferably not less than 0.05 mm and more preferably not less than 0. 1 mm . This yields an effect that the interlayer bonding between the waterproof layer 1 and the fusing layer 2 is even more superior. The thickness of the bonding layer 4 may be, for example, not more than 2 mm, and is preferably not more than 1 mm and more preferably not more than 0.5 mm. This yields the effect of having excellent handleability at the time of construction in that the weight of the roll does not become too large when the waterproof sheet is formed into a roll shape, the roll length of the roll can be increased, and the like.

The thickness of the waterproof sheet 10 is, for example, not less than 0. 1 mm, and is preferably not less than 0.5 mm and more preferably not less than 1 mm. This yields an effect that the durability of the waterproof structure is even more superior. Specifically, this yields the effect of having excellent penetration resistance as defined in Waterproof Test II of the Structure- Related Test Method of the NEXCO Test Method (4th Edition) (July 2015) . The thickness of the waterproof sheet 10 may be, for example, not more than 10 mm, and is preferably not more than 7 mm and more preferably not more than 5 mm. This yields the effect of having excellent handleability at the time of construction in that the weight of the roll does not become too large when the waterproof sheet is formed into a roll shape, the roll length of the roll can be increased, and the like .

The waterproof sheet 10 may be further provided with other layers in addition to the waterproof layer 1 , the fusing layer 2, the adhesive agent layer 3 , and the bonding layer 4. For example, the waterproof sheet 10 may be provided with a protective layer for protecting the adhesive agent layer 3 on the adhesive agent layer 3. In addition, the waterproof sheet 10 may be provided with a protective layer for protecting the fusing layer 2 on the fusing layer 2. These protective layers are peeled at the time of the construction of the waterproof structure . In addition, the waterproof sheet 10 may be further provided with a reinforcement layer made of a cross substrate, a nonwoven fabric, or the like as another layer.

The waterproof sheet 10 is used to form a waterproof structure on a road to be paved with asphalt. The waterproof sheet 10 can be particularly suitably used in the construction of a waterproof structure of a concrete road (for example, a bridge) where problems such as deterioration or cracking occur due to the infiltration of water. Waterproof structure and construction method thereof

FIG. 2 is a cross-sectional view illustrating an overview of the waterproof structure according to an embodiment. The waterproof structure 20 according to the present embodiment comprises the waterproof sheet 10 described above and an asphalt pavement 5 laid on the fusing layer 2 of the waterproof sheet 10. In FIG. 2, the waterproof structure 20 comprises an underlying layer 7 serving as the object of construction and a treatment layer 6 containing an unevenness adjusting agent formed on the surface of the underlying layer 7.

The asphalt pavement 5 is not particularly limited, and a known asphalt pavement may be used. The thickness of the asphalt pavement 5 may be, for example, not less than 200 mm or not less than 75 mm. In addition, the thickness of the asphalt pavement 5 may be, for example, not less than 50 mm or not less than 25 mm.

The underlying layer 7 is the road to be paved with asphalt and may be made of concrete (for example, a concrete slab), for example.

The unevenness adjusting agent is used primarily to flatten the convexities and concavities (unevenness) of the surface of the underlying layer 7. Examples of unevenness adjusting agents include resin mortars such as latex-modified mortars, epoxy asphalt mixtures, gussasphalt mixtures, and acrylic resin mortars, and thermosetting resins such as epoxy resins and acrylic resins. Of these, it is preferable to use an epoxy asphalt mixture from the perspective that the composition becomes resistant to the effects of impurities on the surface of the underlying layer 7 (for example, residual matter such as the asphalt pavement described below) and that construction can be completed in a short amount of time.

The thickness of the treatment layer 6 containing the unevenness adjusting agent may be, for example, not less than 5 mm or not less than 15 mm. In addition, the thickness of the treatment layer 6 may be, for example, not less than 50 mm or not less than 30 mm.

FIGS. 3 A to 3C are diagrams for explaining the construction method of the waterproof structure according to an embodiment. As illustrated in FIGS. 3A to 3C, the waterproof structure 20 may be produced, for example, by a construction method comprising the steps of: disposing the waterproof sheet 10 described above on a construction face A so that the adhesive agent layer 3 is on the construction face A side (see FIG. 3B); and laying the asphalt pavement 5 on the fusing layer 2 of the waterproof sheet 10 (see FIG. 3C).

The construction method for the waterproof structure 20 may further include a step of forming the construction face A by laying a treatment layer 6 containing an unevenness adjusting agent on the surface of the underlying layer 7, as illustrated in FIG. 3A.

The construction face A may be the surface of the underlying layer 7. When a treatment layer 6 is formed on the surface of the underlying layer 7, the construction face A may be the face of the treatment layer 6 on the opposite side as the under 7.

In the step of laying the asphalt pavement 5, the heated asphalt pavement 5 may be pressurized after being laid uniformly on the fusing layer 2. In this case, the fusing layer 2 melts due to the heat of the asphalt pavement 5, and the fusing layer 2 and the asphalt pavement 5 are fused together. The heating temperature at the time of the paving of the asphalt pavement 5 is preferably a temperature at which the fusing layer 2 can melt and may be, for example, not less than 200°C or not less than 170°C . In addition, the heating temperature of the asphalt pavement 5 may be, for example, not more than 100°C or not more than 130°C.

When the waterproof structure 20 is constructed for the purpose of repairing an asphalt- paved road, the construction method in the present embodiment may further comprise a step of exposing the surface of the underlying layer 7 by removing the existing asphalt pavement, waterproof layer, or the like. The existing asphalt pavement or the like may be removed by a publicly known method. For example, a method using an excavator such as a back hoe may be used. When residual matter such as asphalt pavement is present, the residual matter may be removed by shot blasting, a water jet, or the like .

A preferred embodiment of the present invention is described above, but the present invention is not limited to the aforementioned embodiment.

Examples

The content of the present invention will be described in further detail hereinafter with reference to working examples and comparative examples, but the present invention is not limited to the following working examples.

Working Example 1

An ethylene-vinyl acetate copolymer (EVA) (trade name : Ultrasen 750 ("Ultrasen" is a registered trademark), manufactured by Tosoh Corporation, melting point: 64°C) was formed into a sheet using an extrusion molding machine to obtain an EVA sheet having a thickness of 0.6 mm (EVA layer, fusing layer). At this time, the temperature of the extruder was maintained at 200°C. Next, after the EVA sheet was gravure-coated with a primer containing a polymeric MDI (polymethylene polyphenyl polyisocyanate) and chlorinated polyolefin (trade name : K500NT, manufactured by 3M, Ltd., solid content: 8 mass%) using a gravure printer (number of lines: 120 lpi), the solvent was dried. As a result, a primer layer was formed on the EVA sheet. Next, a thermoplastic urethane resin (TPU) (trade name : Elastran ET385 ("Elastran" is a registered trademark), manufactured by BASF, JIS A hardness after curing: 85) was extruded to form a TPU layer (waterproof layer) on the surface of the primer layer on the opposite side as the EVA sheet. The thickness of the TPU layer was set to 0.2 mm. As a result, a laminated sheet comprising a fusing layer, a bonding layer, and a waterproof layer was obtained. The thickness of the laminated sheet was 0.8 mm.

Next, an acrylic foam tape having a thickness of 1 mm (trade name : 4481 MH, manufactured by 3M, Ltd.) was laminated on the surface of the laminated sheet on the TPU layer side to obtain a waterproof sheet of Working Example 1.

Working Example 2 A thermoplastic urethane resin (TPU) (trade name : Elastran ET385, manufactured by BASF) was formed into a sheet using an extrusion molding machine to obtain a TPU sheet having a thickness of 0.2 mm (TPU layer, waterproof layer) . At this time, the temperature of the extruder was maintained at 200°C. Next, after the TPU sheet was gravure-coated with a primer containing a polymeric MDI and chlorinated polyolefin (trade name : K500NT, manufactured by 3M, Ltd., solid content: 8 mass%) using a gravure printer (number of lines : 120 lpi), the solvent was dried. As a result, a primer layer was formed on the TPU sheet. Next, an EVA sheet produced in the same manner as in Working Example 1 (thickness : 0.6 mm) was laminated at 80°C on the surface of the primer layer on the opposite side as the TPU sheet using a heat roll . As a result, an EVA layer (fusing layer) was formed, and a laminated sheet comprising a fusing layer, a bonding layer, and a waterproof layer was obtained. The thickness of the laminated sheet was 0.8 mm.

Next, an acrylic foam tape having a thickness of 1 mm (trade name : 4481 MH, manufactured by 3M, Ltd.) was laminated on the surface of the laminated sheet on the TPU layer side to obtain a waterproof sheet of Working Example 2.

Working Example 3

TPU (trade name : Elastran ET385 , manufactured by BASF) and a resin composition containing an ethylene-vinyl acetate copolymer and a tackifier (Mercen MX06, manufactured by Tosoh Corporation) were coextruded onto an EVA sheet produced in the same manner as in

Working Example 1 (EVA layer: thickness: 0.6 mm) . As a result, a laminated sheet in which a bonding layer (thickness : 0.2 mm) and a TPU layer (thickness: 0.2 mm) were formed on an EVA sheet in this order was obtained. The total thickness of the laminated sheet was 1 .0 mm. Note that the temperature of the extruder was maintained at 170 to 200°C.

Comparative Example 1

EVA (trade name : Ultrasen 750, manufactured by BASF) and TPU (trade name : ET385, manufactured by 3M, Ltd.) were coextruded onto an EVA sheet produced in the same manner as in Working Example 1 (first EVA layer, thickness: 0.6 mm) . As a result, a laminated sheet in which an EVA layer (second EVA layer, thickness: 0.2 mm) and a TPU layer (thickness: 0.2 mm) were formed on an EVA sheet in this order was obtained. The total thickness of the laminated sheet was 1 .0 mm.

Next, an acrylic foam tape having a thickness of 1 mm (trade name : 4481 MH, manufactured by 3M, Ltd.) was laminated on the surface of the laminated sheet on the TPU layer side to obtain a waterproof sheet of Comparative Example 1 .

Adhesion evaluation

T-type peeling test A T-type peeling test was performed using the laminated sheets of the working examples and the comparative examples. Specifically, the interlayer adhesive force (T-type peeling bond strength) between the EVA layer and the TPU layer of the laminated sheet was measured by gripping each of the TPU layer and the EVA layer with a tensile tester chuck and pulling the layers at a rate of 300 mm/min (peeling rate) using the tensile tester prescribed in JIS Z0237 (2009). The peeling angle was set to 180°. The results are shown in Table 1. Note that in Comparative Example 1, the interlayer adhesive force between the second EVA layer and the TPU layer (T-type peeling bond strength) was measured.

Tensile test

A tensile test was performed using the waterproof sheets of the working examples and the comparative examples. Specifically, as illustrated in FIG. 4, the tensile bond strength of the waterproof structure was measured at 23°C in accordance with the Specifications for

Waterproofing Highway Bridges (published by the Japan Road Association). In FIG. 4, 5 is an asphalt pavement, 7 is concrete, 8 is a jig, 10 represents the waterproof sheets of the working examples and the comparative examples, and the arrows indicate the load directions. The results are shown in Table 1.

[Table 1]

It was confirmed from the working examples described above that a waterproof structure having excellent durability can be easily constructed in a short amount of time with the waterproof sheet according to the present invention.

Reference Signs List

1 : Waterproof layer

2: Fusing layer

3 : Adhesive agent layer

4: Bonding layer

5 : Asphalt pavement

6: Treatment layer

7: Underlying layer : Jig

0: Waterproof sheet0: Waterproof structure