Water shielding sheet and method for manufacturing water shielding sheet

Abstract

To provide a water shielding sheet which is excellent in environmental characteristics and mechanical characteristics, and is formed by downsizing a fixing work of fixing the sheet to a normal slope of a waste disposal site, and a method for manufacturing the same.SOLUTION: A water shielding sheet is held by a fixing work and is derived from an olefin resin composition, and satisfies at least the following structures (A) to (D): (A) a biomass degree of the olefin resin composition according to ASTM D 6866 of 5 to 40%; (B) a 1%-cleavage line elastic coefficient (E0) at 0°C, which is measured according to JIS K 7127:1999, of 150 to 350 N / mm2; (C) a water permeability coefficient of 1×10-9 cm / sec or less; and (D) tensile strength measured according to JIS K 6251:2017 of 950 N / cm2 or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a waterproof sheet and a method for manufacturing the waterproof sheet. More specifically, the present invention provides a waterproof sheet that has excellent environmental properties (such as reduced CO2 emissions) and mechanical properties such as tensile strength, and requires smaller fixing work when fixing it to slopes or the like at waste disposal sites, as well as an efficient method for manufacturing such a waterproof sheet. [Background technology]

[0002] Conventionally, at the development sites and reservoirs of waste disposal sites (including industrial waste disposal sites and general waste disposal sites), or at the construction sites thereof, construction has been carried out using specified waterproof sheets to prevent leachate (sewage) from the waste due to rainfall or watering from migrating into the soil outside the disposal site. In such waste disposal sites, a predetermined waterproof sheet is laid at least along the slope, and after waterproofing work is completed, waste is stored. The waterproof sheets used for such waterproofing construction are required to be highly resistant to the tensile stresses that are expected to occur within waste disposal sites, such as the pull load caused by waste, and to be resistant to damage caused by waste, etc.

[0003] Therefore, for example, a waterproof sheet has been proposed that is formed using a material that uses high-pressure low-density polyethylene or / and low-pressure linear low-density polyethylene as a base, to which specific low-pressure linear ultra-low-density polyethylene and ethylene-vinyl acetate copolymer have been added, because these materials have excellent heat-sealing properties and tensile strength and relatively good conformability to the shape of the substrate (see, for example, Patent Document 1). More specifically, for 100 parts by weight of (A) high-pressure low-density polyethylene or / and low-pressure linear low-density polyethylene having a melt flow rate of 0.1 to 10 g / 10 min (190°C), (B) a density of 0.890 to 0.914 g / cm 3This waterproof sheet is made by blending 2 to 50 parts by weight of linear ultra-low density polyethylene and (C) 1 to 30 parts by weight of an ethylene-vinyl acetate copolymer having a melt flow rate of 0.8 to 40 g / 10 min (190°C) and containing 10 to 40% by weight of vinyl acetate units.

[0004] In addition, a polyolefin-based civil engineering waterproof sheet has been proposed that limits the density, melt index, and ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) of a specified ethylene-α-olefin copolymer and also contains 1 to 20 weight % of an inorganic filler (see, for example, Patent Document 2). More specifically, it is a copolymer of (a) ethylene and an α-olefin having 3 to 12 carbon atoms, polymerized using a metallocene catalyst, and (b) has a density of 0.86 g / cm 3 ~0.88g / cm 3 (c) a melt index of 0.5 to 5 g / min, and (d) a weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of 1.5 to 5, and the polyolefin-based waterproof sheet for civil engineering uses is composed of an ethylene-α-olefin copolymer containing 1 to 20% by weight of inorganic filler having an average particle size of 1 to 20 μm.

[0005] Furthermore, a synthetic resin civil engineering sheet has been proposed, which contains a predetermined amount of barium sulfate and one or more selected from other inorganic compounds and metal powders, and which contains a predetermined amount of an ethylene-α-olefin copolymer in which the 1% secant elastic modulus of the sheet is limited, and the density, melt flow rate, and ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) are limited (see, for example, Patent Document 3). More specifically, it is a synthetic resin civil engineering sheet that contains 15 to 50 weight percent of barium sulfate and one or more selected from other inorganic compounds and metal powders in a specified weight ratio (100:0 to 50:50), and has a 1% secant elastic modulus of 30 to 200 MPa. The synthetic resin is (a) a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms obtained by polymerization using a metallocene catalyst, and (b) has a density of 0.86 to 0.94 g / cm. 3and (c) a melt flow rate (MFR) of 0.5 to 5 g / 10 min, and (d) a ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 1.5 to 5. The synthetic resin sheet for civil engineering uses contains 1 to 99% by weight of an ethylene-α-olefin copolymer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 8-143723 A (Claims, etc.) [Patent Document 2] JP 9-157456 A (Claims, etc.) [Patent Document 3] Patent No. 4185375 (Claims, etc.) Summary of the Invention [Problem to be solved by the invention]

[0007] Here, the waterproof sheets and the like of Patent Documents 1 to 3 are laid on the slopes of waste disposal sites and are used with their edges held in place by fixing structures, and are required to have a certain level of durability and mechanical strength, etc., and the fixing structures that hold them in place are also desired to be lightweight and compact in terms of ease of molding and dismantling, etc. However, the weight of such fixing works is designed taking into consideration the strength of the waterproof sheet, and therefore has conflicting characteristics with improving the durability and mechanical strength of the waterproof sheet. In other words, when trying to improve the durability and mechanical strength of the waterproof sheet by improving the strength, etc. of the waterproof sheet, the waterproof sheet tends to become heavier, and the fixing work that secures it also becomes heavier and larger, which is a problem.

[0008] On the other hand, there is a demand for environmentally friendly products such as waterproof sheets, and products that reduce the environmental impact are desired. However, the waterproof sheets and the like in Patent Documents 1 to 3 are each made solely from petroleum-derived olefin resins, and do not take biomass content into consideration at all, so they are unable to satisfy the environmental characteristic of reducing CO2 emissions. Furthermore, depending on the amount of petroleum-derived olefin resin used, there is concern that excessive use of petroleum-derived olefin resin may lead to problems such as accelerated resource depletion. In order to solve this problem, the use of plant-derived olefins as olefin resins has been investigated. However, plant-derived olefins have inferior mechanical strength, such as tensile strength, compared to petroleum-derived olefins, and there was concern that if they were used directly as a constituent material for waterproof sheets, their durability would be easily reduced.

[0009] Therefore, as a result of intensive research, the inventors have completed the present invention by constructing a waterproof sheet derived from an olefin resin composition having a specified biomass content as at least components (A) to (D), and by controlling the 1% secant elastic modulus at 0°C, the water permeability coefficient, and the tensile strength to values ​​within predetermined ranges. In other words, the present invention aims to provide a waterproof sheet that has excellent environmental properties and contradictory properties such as tensile strength, and when laid on slopes or the like of waste disposal sites, the fixing work that holds it in place is lightweight, and an efficient method for manufacturing such a waterproof sheet. [Means for solving the problem]

[0010] According to the present invention, there is provided a waterproof sheet derived from an olefin resin composition, which is laid on at least the slope of a waste disposal site and whose edges are held in place by fixings, and which is characterized by satisfying the following configurations (A) to (D), thereby solving the above-mentioned problems. (A) The biomass content of the olefin resin composition according to ASTM D6866 is within the range of 5 to 40%. (B) The 1% secant elastic modulus (E0) at 0°C, measured in accordance with JIS K7127:1999 (equivalent to ISO5273:2012), is 150 to 350 N / mm 2 The value is in the range. (C) Permeability coefficient is 1 × 10 -9 The value is less than cm / sec. (D) Tensile strength measured in accordance with JIS K6251:2017 is 950N / cm 2 The above values. By satisfying the configurations (A) to (D) in this way, the occurrence of thermal stress in the fixing structure can be suppressed, and in turn, the size and weight of the fixing structure can be reduced. Moreover, durability and mechanical properties can be improved while taking environmental characteristics into consideration.

[0011] In constructing the waterproof sheet of the present invention, when the thermal stress defined by the following formula in the fixing work that holds the waterproof sheet is T2, T2 is set to 1000 to 10000 (N / m 2 ) is preferably within the range.

[0012]

number

[0013] In this way, by specifically limiting the thermal stress (T2) in the fixing work based on the 1% secant elastic modulus at 0°C, etc., the occurrence of thermal stress in the fixing work can be suppressed, and ultimately, the size and weight of the fixing work can be reduced.

[0014] When constructing the waterproof sheet of the present invention, it is preferable to set the minimum air temperature used in calculating the thermal stress (T2) in the waterproof sheet to a value within the range of -45 to 5°C. By configuring it in this way, it becomes easy to provide waterproof sheets with safe and reliable fixing structures that are suitable for each region of Japan (e.g., Tokyo, Sapporo, Okinawa), even taking into account the drop in winter temperatures due to recent environmental changes.

[0015] When constructing the waterproof sheet of the present invention, it is preferable to set the maximum temperature used in calculating the thermal stress (T2) in the waterproof sheet to a value within the range of 30 to 50°C. By configuring it in this way, it becomes easy to provide a waterproof sheet with fixing works that is suitable for any part of Japan (e.g., Tokyo, Sapporo, Okinawa), even taking into account the rise in summer temperatures due to recent environmental changes.

[0016] When constructing the waterproof sheet of the present invention, it is preferable that the olefin resin composition contains, as the first polyolefin resin, an olefin copolymer of petroleum-derived ethylene and an α-olefin having 3 to 12 carbon atoms, and, as the second polyolefin resin, an olefin copolymer of plant-derived ethylene and an α-olefin having 3 to 12 carbon atoms. By configuring it in this manner, not only can the biomass content of the olefin resin composition be easily adjusted in relation to the first olefin copolymer and the second olefin copolymer, but excellent compatibility and mechanical properties can also be obtained.

[0017] When constructing the waterproof sheet of the present invention, it is preferable that the waterproof sheet has a multilayer structure having at least a waterproof sheet on the front side and a waterproof sheet on the back side, and that the waterproof sheet on the front side is a predetermined color and the waterproof sheet on the back side is a color different from the predetermined color. By configuring it in this manner, even if there is a pinhole or the like in the waterproof sheet on the front side of a specified color, other colors in the waterproof sheet on the back side can be seen through the pinhole or the like, even with the naked eye, and thus pinholes or the like in the waterproof sheet on the front side, etc. can be quickly and easily confirmed.

[0018] In constructing the water-shielding sheet of the present invention, it is preferably placed between the shading protective mat and the protective substrate, and forms part of the water-shielding multi-layer structure. By constructing a waterproof sheet that is applied to at least one layer of such a waterproof multilayer structure, even better weather resistance, durability, mechanical strength, etc. can be obtained depending on the application, and the weight of the fixing work can be reduced even in the case of a waterproof multilayer structure.

[0019] Another aspect of the present invention is a method for producing a waterproof sheet derived from an olefin resin composition, which is laid on at least the slope of a waste disposal site and whose edges are held in place by fixings, and which is characterized by comprising the following steps (1) to (2): Step (1): A step of mixing an olefin resin composition containing a first polyolefin resin containing petroleum-derived ethylene units and a second polyolefin resin containing plant-derived ethylene units, and adjusting the biomass ratio in accordance with ASTM D6866 to a value within a range of 5 to 40% as configuration (A). Step (2): A step of producing a waterproof sheet derived from an olefin resin composition and satisfying the following requirements (B) to (D). (B) The 1% secant elastic modulus (E0) at 0°C measured in accordance with JIS K7127:1999 is 150 to 350 N / mm 2 The value is in the range. (C) Permeability coefficient is 1 × 10 -9 The value is less than cm / sec. (D) Tensile strength measured in accordance with JIS K6251:2017 is 950N / cm 2 The above values. In this way, by using a specified olefin resin composition to produce a waterproof sheet that satisfies at least structures (B) to (D) and is derived from an olefin resin composition that satisfies structure (A), it is possible to efficiently provide a waterproof sheet that is excellent in reducing CO2 emissions, has excellent mechanical properties such as tensile strength, and reduces the size and weight of fixing work when laid on a slope. [Brief explanation of the drawings]

[0020] [Figure 1]Figure 1(a) is a diagram provided to explain how the waterproof sheet is used at a waste disposal site, Figure 1(b) is a side view provided to explain the bonding state of the waterproof sheet, Figure 1(c) is a top view provided to explain the bonding state of the waterproof sheet, and Figure 1(d) is a diagram (photograph) provided to explain how the waterproof sheet is used at an actual waste disposal site. [Figure 2] 2(a) to 2(e) are diagrams provided to explain the configuration of the waterproof sheet (single layer structure, homogeneous and heterogeneous multi-layer structure, etc.). [Figure 3] Figure 3(a) is a diagram used to explain the relationship between the biomass ratio of a waterproof sheet and the evaluation of environmental characteristics, Figure 3(b) is a diagram used to explain the relationship between the biomass ratio of a waterproof sheet and tensile strength, and Figure 3(c) is a diagram used to explain the relationship between the biomass ratio and joint shear strength. [Figure 4] FIG. 4 is a diagram provided to explain the relationship between the blending amount of the second olefin resin relative to the total amount of the olefin resin and the biomass ratio of the water-shielding sheet. [Figure 5] Figure 5(a) is a diagram used to explain the relationship between the biomass content of the waterproof sheet and the 1% secant elastic modulus at 0°C in the fixed structure, and Figure 5(b) is a diagram used to explain the relationship between the 1% secant elastic modulus at 0°C in the fixed structure and the tensile strength of the waterproof sheet. [Figure 6] FIG. 6 is a diagram provided for explaining the relationship between the blending amount of the second olefin resin relative to the total amount of the olefin resin and the 1% secant elastic modulus at 0° C. in the fixing structure. [Figure 7] Figure 7(a) is a diagram used to explain the relationship between the amount of the second olefin resin relative to the total amount of olefin resin and the thermal stress T2 of the fixed work in Tokyo, and Figure 7(b) is a diagram used to explain the relationship between the amount of the second olefin resin relative to the total amount of olefin resin and the thermal stress T2 of the fixed work in Tokyo. [Figure 8]Figure 8(a) is a diagram used to explain the relationship between the amount of the second olefin resin relative to the total amount of olefin resin and the thermal stress T2 of the fixed work in Sapporo, and Figure 8(b) is a diagram used to similarly explain the relationship with the size of the fixed work in Sapporo. [Figure 9] Figure 9(a) is a diagram used to explain the relationship between the amount of the second olefin resin relative to the total amount of olefin resin and the thermal stress T2 of the fixed work in Okinawa, and Figure 9(b) is a diagram used to explain the relationship between the amount of the second olefin resin relative to the total amount of olefin resin and the thermal stress T2 of the fixed work in Okinawa, and similarly, [Figure 10] 10(a) and 10(b) are diagrams provided to explain the cross-sectional view and the plan view of a multilayer structure made up of waterproof sheets of different colors. [Figure 11] FIG. 11(a) is a diagram provided for explaining the 1% secant elastic modulus in the SS curve, and FIG. 11(b) is a diagram provided for explaining the temperature dependency of the 1% secant elastic modulus. DETAILED DESCRIPTION OF THE INVENTION

[0021] [First embodiment] The first embodiment provides a waterproof sheet derived from an olefin resin composition that is laid on at least the slope of a waste disposal site and whose edges are held in place by fixings, and that is characterized by satisfying the following configurations (A) to (D), thereby solving the above-mentioned problems. (A) The biomass content of the olefin resin composition according to ASTM D6866 is within the range of 5 to 40%. (B) The 1% secant elastic modulus (E0) at 0°C measured in accordance with JIS K7127:1999 is 150 to 350 N / mm 2 The value is in the range. (C) Permeability coefficient is 1 × 10 -9 The value is less than cm / sec. (D) Tensile strength measured in accordance with JIS K6251:2017 is 950N / cm 2 The above values. The waterproof sheet of the first embodiment will be specifically described below with reference to the drawings as appropriate.

[0022] 1. Basic structure of waterproof sheet The basic structure of the waterproof sheet is a waterproof sheet 10 (which also includes a resin sheet made by rolling up a long waterproof sheet into a roll; the same applies below) that is laid at least along the slope in a developed area 14 of a waste disposal site, etc., as shown in Figure 1(a). Therefore, such waterproof sheets adopt the configurations shown in Figs. 2(a) to (d) depending on the application. Typically, in the developed land 14 of a waste disposal site where such waterproof sheets are laid, accumulated water is drained outside the site through drainage pipes or the like. On the other hand, the waterproof sheet 10 is a resin sheet derived from a specified olefin resin composition that is laid directly or indirectly on the developed land 14 of a waste disposal site to prevent water (contaminated water) flowing out from the waste 12 from seeping into the soil and to exert a waterproofing effect on the laid surface for a long period of time. Such waterproof sheets are basically made from a specified olefin resin composition, and have excellent waterproofing and environmental properties, as well as specified mechanical properties such as tensile strength.

[0023] 2. Olefin resin composition The olefin resin composition that constitutes the waterproof sheet is not particularly limited as long as it is a resin composition primarily composed of an olefin polymer derived from an olefin monomer, but it is preferable that it be a polyolefin resin containing petroleum-derived ethylene units (sometimes referred to as a first polyolefin resin), and a polyolefin resin containing plant-derived ethylene units (sometimes referred to as a second polyolefin resin), or a resin composition containing either one of them. That is, the reason for using an olefin resin composition containing the first polyolefin resin and the second polyolefin resin is that it is easy to adjust predetermined mechanical properties, durability, etc., and to exhibit desired properties. More specifically, it is even more preferable to blend a first polyolefin resin containing petroleum-derived ethylene units with a second polyolefin resin containing plant-derived ethylene units that takes environmental characteristics into consideration, and to maintain predetermined mechanical properties, durability, etc. by balancing the two.

[0024] (1) First polyolefin resin (petroleum-based polyolefin resin) 1) Type The type of monomer that constitutes the petroleum-derived ethylene unit that constitutes the first polyolefin resin (sometimes referred to as a petroleum-based polyolefin resin) is not particularly limited, as long as it is an ethylene monomer that can be obtained by polymerizing the first polyolefin resin containing at least an ethylene unit using a specified catalyst (such as a Ziegler-Natta catalyst or a metallocene catalyst). In particular, polyolefin resins obtained by polymerization using a metallocene catalyst are preferred polyolefin resins because they are highly stereoregular and have relatively high strength and good heat resistance. The first polyolefin resin is a petroleum-derived resin derived from plants and substantially free of ethylene units, unlike the second polyolefin resin described below. Furthermore, as the type of monomer that constitutes the petroleum-derived ethylene unit that constitutes the first polyolefin resin, it is preferable to blend an α-olefin having 3 to 12 carbon atoms that copolymerizes with ethylene monomer as a copolymerization monomer. The reason for this is that by using an ethylene-based copolymer as the first polyolefin resin, the compatibility between the first polyolefin resin and the second polyolefin resin can be improved, and various mechanical properties, thermal properties, polymerizability, etc. of the first polyolefin resin can also be improved. Therefore, it is preferable to blend, as such an α-olefin having 3 to 12 carbon atoms, propylene, 1-butene, isobutene, 1-pentene, 1-hexene, 2-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-octene, 1-nonene, 1-decene, etc., alone or in combination.

[0025] 2) Biomass content The biomass content of the first polyolefin resin is essentially 0% because it does not contain C14, which is an isotope of C12. However, since compatibility with the second polyolefin resin is further improved, the biomass content of the first polyolefin resin as the first polyolefin resin is more preferably 1% or less, and even more preferably 0.1% or less. The biomass degree of the first polyolefin resin can be measured in accordance with ASTM D6866, similarly to the biomass degree of the second polyolefin resin, etc., which will be described later.

[0026] 3) Blend amount It is preferable to determine the amount of the first polyolefin resin, taking into consideration the amount of the second polyolefin resin used in combination, so that the biomass content of the olefin resin composition that makes up the waterproof sheet is within the range of 5 to 40%. The reason for this is that if the biomass ratio is less than 5% or, conversely, exceeds 40%, it may become difficult to achieve both mechanical properties such as tensile strength and environmental properties. Therefore, it is more preferable to set the biomass degree to a value within the range of 7 to 30%, and even more preferable to set it to a value within the range of 8 to 20%. More specifically, in order to adjust the biomass degree, it is preferable to set the ratio of the blending amount of the first polyolefin resin to the blending amount of the second polyolefin resin to a value within the range of 95 / 5 to 60 / 40 in weight terms. The reason for this is that if the ratio of the amount of the first polyolefin resin to the amount of the second polyolefin resin exceeds 95 / 5, the biomass content will be low, and the reduction in environmental impact may be insufficient. On the other hand, if the ratio of the amount of the first polyolefin resin to the amount of the second polyolefin resin is less than 60 / 40, the tensile strength will be low, the durability of the waterproof sheet within the disposal site will be low, and it may be more susceptible to damage. Therefore, when the total amount of the olefin resin composition is 100% by weight, the amount of the first polyolefin resin is preferably 60 to 95% by weight, more preferably 70 to 93% by weight, and even more preferably 75 to 90% by weight. The biomass degree of the second polyolefin (described below) varies somewhat depending on the purity of the biomass-derived pellets used. Therefore, it is preferable to set the blending amounts of the first polyolefin resin and the second polyolefin resin according to the purity of the biomass-derived pellets used so that the olefin resin composition constituting the water-shielding sheet has the desired biomass degree.

[0027] 4) Weight average molecular weight / melt flow rate The weight average molecular weight of the first polyolefin resin is not particularly limited and can be changed appropriately according to the desired physical properties. In addition, in view of the mechanical properties and durability of the waterproof sheet, it is preferable that the weight average molecular weight is set to a value within the range of 120,000 to 200,000. The reason for this is that if the weight average molecular weight of the first polyolefin resin becomes less than 120,000 or, conversely, exceeds 200,000, its compatibility with the second polyolefin resin decreases, and the water-proofing, mechanical properties such as tensile strength, and durability of the water-proof sheet of the first embodiment may be significantly reduced. Therefore, in the amount of the first polyolefin resin blended, it is more preferable that the weight average molecular weight be set to a value within the range of 150,000 to 190,000, and even more preferably to a value within the range of 160,000 to 185,000. For clarity, it is preferable that the weight average molecular weight of the first polyolefin resin is smaller than that of the second polyolefin resin described below.

[0028] Furthermore, the melt flow rate (MFR) of the first polyolefin resin in accordance with JIS K7210 is preferably set to a value within the range of 1 to 3 g / 10 minutes under conditions of 190° C. and a load of 2.16 kg. The reason for this is that if the melt flow rate of the first polyolefin resin is less than 1 g / 10 min, the fluidity will be poor and the compatibility with the second polyolefin resin may decrease. Furthermore, if the melt flow rate of the first polyolefin resin exceeds 3 g / 10 min, the viscosity may be too low, making molding difficult. Therefore, the melt flow rate of the first polyolefin resin is more preferably set to a value within the range of 1.3 to 2.8 g / 10 min, and even more preferably set to a value within the range of 1.5 to 2.5 g / 10 min.

[0029] 5) Density The density of the first polyolefin resin is not particularly limited and can be changed appropriately according to the desired physical properties. However, from the viewpoint of the strength of the waterproof sheet, it is usually 0.88 to 0.94 g / cm 3 It is preferable to set the value within the range. The reason for this is that the density of the first polyolefin resin is 0.88 g / cm 3 Less than 0.94g / cm 3 If the value exceeds this, the compatibility with the second polyolefin resin will decrease, and the water-proofing, mechanical properties such as tensile strength, and durability of the waterproof sheet of the first embodiment may be significantly reduced. Therefore, in the first polyolefin resin, the density is set to 0.90 to 0.915 g / cm 3 It is more preferable to set the value within the range of 0.905 to 0.912 g / cm 3 It is more preferable that the value is within the range of For clarity, it is preferable that the density of the first polyolefin resin is greater than the density of the second polyolefin resin.

[0030] 6) Melting point When the first polyolefin resin shows a crystalline melting peak as measured by a DSC (differential scanning calorimeter) or the like, it is determined that the first polyolefin resin has a melting point corresponding to the temperature of the peak value. The melting point is not particularly limited and can be changed appropriately according to the desired physical properties, but it is usually preferable to set it to a value within the range of 85 to 125°C. The reason for this is that if the melting point of the first polyolefin resin is less than 85°C or, conversely, more than 125°C, the mechanical properties of the olefin resin composition may be significantly reduced, or the compatibility with the second polyolefin resin may be reduced. Therefore, the melting point of the first polyolefin resin is more preferably set to a value within the range of 87 to 120°C, and even more preferably set to a value within the range of 90 to 115°C. For clarity, it is preferable that the melting point of the first polyolefin resin is lower than the melting point of the second polyolefin resin.

[0031] Furthermore, it is preferable that the first polyolefin resin has a melting enthalpy (ΔH) measured using DSC or the like, within a range of 90 to 130 mJ / mg. Furthermore, it is preferable that the crystallinity value of the first polyolefin resin is limited to a value within the range of 30 to 50%. It is preferable that the melting enthalpy (ΔH) and the crystallinity of the first polyolefin resin are smaller than those of the second polyolefin resin.

[0032] 7) Elastic modulus (1% secant elastic modulus) The 1% secant elastic modulus (hereinafter sometimes simply referred to as elastic modulus) of the first polyolefin resin at 0° C. is not particularly limited, and can be changed appropriately according to the desired physical properties. In addition, from the viewpoint of the mechanical properties and handling properties of the olefin resin composition, the elastic modulus is set to 150 to 350 N / mm 2 It is preferable to set the value within the range. The reason for this is that the modulus of elasticity of the first polyolefin resin is 150 N / mm2 The value may be less than 350N / mm 2 If the value exceeds this, the mechanical properties and handling properties of the olefin resin composition may be significantly reduced, and the compatibility with the second polyolefin resin may be reduced. Therefore, the elastic modulus of the first polyolefin resin is set to 190 to 280 N / mm 2 It is more preferable to set the value within the range of 200 to 240 N / mm 2 It is more preferable that the value is within the range of Furthermore, as shown in Example 1, the first polyolefin resin was formed into a film by a predetermined method, and the elastic modulus was calculated by dividing the stress value at a strain of 1% in the stress-strain curve measured in accordance with JIS K7127:1999 by the cross-sectional area and strain. A more specific method for calculating the elastic modulus will be shown in Example 1 and the like.

[0033] 8) Hayes Furthermore, the haze value, which is an index showing the transparency of the first polyolefin resin and conforms to JIS K7136:2000, is preferably set to a value within the range of 0.5 to 15%. The reason for this is that if the haze of the first polyolefin resin is less than 0.5% or, conversely, exceeds 15%, the yield during production of the olefin resin composition, mechanical properties, and even handleability may be significantly reduced, and the compatibility with the second polyolefin resin used in combination may be reduced. Therefore, in the first polyolefin resin, the haze is more preferably set to a value within the range of 1 to 12%, and even more preferably to a value within the range of 3 to 10%. For clarity, it is preferable that the haze of the first polyolefin resin is greater than the haze of the second polyolefin resin.

[0034] (2) Second polyolefin resin (plant-based polyolefin resin) 1) Type The second polyolefin resin is an olefin polymer derived from ethylene monomers (which may contain some oligomers; the same applies below) produced from alcohol obtained from plants, and is an olefin copolymer containing ethylene units derived from plant materials (sometimes referred to as plant-based polyolefin resin). That is, the second polyolefin resin is an olefin copolymer having predetermined properties, obtained by subjecting ethylene monomers derived from plants to coordination-insertion polymerization or the like. Therefore, commercially available products such as LLDPE (including copolymers) can also be used as the second polyolefin resin.

[0035] Examples of such commercially available products include the following LLDPE, LDPE, and HDPE manufactured by Braskems. More specifically, SLL118 (biomass content: 87%, LLDPE copolymer with 1-butene), SLL118 / 21 (biomass content: 87%, LLDPE copolymer with 1-butene), SLL318 (biomass content: 87%, LLDPE copolymer with 1-butene), SLH118 (biomass content: 84%, LLDPE), SLH218 (biomass content: 84%, LLDPE copolymer with 1-hexene), SLH082 / 30AF (biomass content: 84%, LLDPE Examples of suitable ethylene glycol olefin copolymers include copolymers with 1-hexene, SBC818 (biomass content: 95%, LDPE), SPB208 (biomass content: 95%, LDPE), SEB853 (biomass content: 95%, LDPE), SPB681 (biomass content: 95%, LDPE), STN7006 (biomass content: 95%, LDPE), SGF4960 (biomass content: 96%, HDPE), SHC7260 (biomass content: 96%, HDPE), and SHD7255LS-L (biomass content: 96%, HDPE).

[0036] The second polyolefin resin may be a polyolefin resin produced by employing a mass balance method certified by ISCC PLUS certification or the like. Polyolefin resins that are classified as biomass products using the mass balance method contribute to reducing the environmental impact when considering the overall production, use, and disposal of various products in the petrochemical industry, and can be used in the same way as second polyolefin resins.

[0037] In addition, it is preferable that the second polyolefin resin contains, as a copolymerization component, an α-olefin having 3 to 12 carbon atoms that copolymerizes with the plant-derived ethylene monomer component. The reason for this is that by blending such a copolymerization component, the compatibility between the second polyolefin resin and the first polyolefin resin can be improved, or various mechanical properties, thermal properties, etc. of the second polyolefin resin can also be improved. Therefore, it is possible to blend monomers similar to the α-olefins having 3 to 12 carbon atoms that are blended into the first polyolefin resin, but it is particularly preferable to blend 1-butene, 1-pentene, 1-hexene, 1-octene, etc., alone or in combination with two or more thereof, into the second polyolefin resin.

[0038] 2) Biomass content Basically, from the viewpoint of environmental consideration, the biomass content of the second polyolefin resin is preferably within a range of 80 to 100%. However, since this will result in better compatibility with the first polyolefin resin, it is more preferable to set the biomass degree of the second polyolefin resin to a value within the range of 85 to 98%, and even more preferable to set it to a value within the range of 90 to 96%.

[0039] 3) Blend amount Furthermore, it is preferable to determine the amount of the second polyolefin resin to be blended, taking into consideration the amount of the first polyolefin resin to be used in combination, so that the biomass content of the olefin resin composition that constitutes the waterproof sheet is 5 to 40%. The reason for this is that if the biomass ratio is less than 5% or, conversely, exceeds 40%, it may become difficult to achieve both mechanical properties such as tensile strength and environmental properties. Therefore, it is more preferable to set the biomass degree to a value within the range of 7 to 30%, and even more preferable to set it to a value within the range of 8 to 20%. More specifically, it is preferable to set the ratio of the blending amount of the second polyolefin resin to the blending amount of the first polyolefin resin to a value within a range of 5 / 95 to 40 / 60 in weight terms, for example, and adjust the biomass degree of the resulting olefin resin composition to a value within a predetermined range. The reason for this is that if the ratio of the amount of the second polyolefin resin to the amount of the first polyolefin resin is less than 5 / 95, the biomass content will be low, and the reduction in environmental impact may be insufficient. On the other hand, if the ratio of the amount of the second polyolefin resin to the amount of the first polyolefin resin exceeds 40 / 60, the tensile strength will be low, the durability of the waterproof sheet within the disposal site will be low, and it may be more susceptible to damage. Therefore, when the total amount of the olefin resin composition is taken as 100% by weight, the amount of the second polyolefin resin is preferably 5 to 40% by weight, more preferably 7 to 30% by weight, and even more preferably 10 to 25% by weight. Furthermore, the biomass content of the second polyolefin may vary depending on the purity of the biomass-derived pellets used. Therefore, it is preferable to set the blending amounts of the first polyolefin resin and the second polyolefin resin in accordance with the purity of the biomass-derived pellets used so that the olefin resin composition constituting the waterproof sheet has the desired biomass content. If the biomass content of the olefin resin composition that makes up the waterproof sheet is 10% or more, it can be given the biomass mark of the Japan Organic Resources Association.

[0040] Here, referring to FIG. 3(a), the relationship between the biomass ratio (%) of the waterproof sheet containing the second polyolefin resin and the like and the evaluation (relative value) of the environmental characteristics based on the CO2 emissions will be explained. In other words, the horizontal axis of Figure 3(a) shows the biomass content (%) of the waterproof sheet, and the vertical axis shows the evaluation value of the environmental characteristics of the waterproof sheet based on CO2 emissions. The environmental characteristics based on the CO2 emissions were evaluated according to the criteria shown in Example 1, and the evaluation value (relative value) of the environmental characteristics was calculated using the following criteria: ◎ = 5 points, ○ = 3 points, △ = 1 point, and × = 0 point. As shown by the characteristic curve in Figure 3(a), when the biomass content (%) of the waterproof sheet is in the range of 0 to 40%, there is a tendency for the evaluation value of the environmental characteristics of the waterproof sheet to increase as the biomass content (%) increases. Furthermore, when the biomass ratio (%) of the waterproof sheet is in the range of values ​​greater than 40%, the evaluation results of the environmental characteristics tend to be almost unchanged regardless of the biomass ratio (%). Therefore, by limiting the biomass ratio (%) of the waterproof sheet to a value within a predetermined range, the CO2 emissions from the waterproof sheet can be adjusted to a value within the predetermined range. As will be described later, it has been found that the biomass content of a waterproof sheet has a certain correlation with the tensile strength of the waterproof sheet, the shear strength of the joints of the waterproof sheet, etc., as shown in Figures 3(b) to (c). Furthermore, as shown by line A corresponding to the example and line B corresponding to the comparative example in Figure 6, it can be seen that there is a certain correlation between the amount of the second polyolefin resin in the olefin resin composition and the 1% secant elastic modulus at 0°C.

[0041] Furthermore, as shown in the examples described below, it can be understood that the relationship between the blending ratio of the second polyolefin resin and the thermal stress T2 of the waterproof sheet and the size of the fixing work, etc., changes depending on the differences in the minimum and maximum temperatures in Tokyo, Sapporo, and Okinawa. Specifically, Figures 7(a)-(b) are graphs assuming Tokyo, where the minimum temperature is -2.7°C and the maximum temperature is 37°C, and the thermal stress T2 of the waterproof sheet and the size of the fixing work are calculated. According to Figures 7(a) to (b), for example, it can be seen that the thermal stress T2 of the waterproof sheet in Tokyo is smaller than that of the comparative example when the blending ratio of the second polyolefin resin is low (for example, about 20% by weight), and the fixing work size can also be kept small, at 610 to 630 mm square or less.

[0042] Furthermore, Figures 8(a)-(b) are graphs assuming Sapporo, where the minimum temperature is -12.6°C and the maximum temperature is 34.1°C, and the thermal stress T2 of the waterproof sheet and the fixing work size are calculated. According to Figures 8(a) to (b), for example, the temperature difference in Sapporo is larger than in Tokyo, and therefore it can be seen that the influence of the blending ratio of the second polyolefin resin on the thermal stress T2 of the waterproof sheet and the fixing work size is greater. On the other hand, when the blending ratio of the second polyolefin resin is low (for example, about 20% by weight), it can be seen that the fixing size can be made small, 640 to 660 mm square or less.

[0043] Furthermore, Figures 9(a)-(b) are graphs assuming Okinawa, in which the thermal stress T2 of the waterproof sheet and the size of the fixing work are calculated for a minimum temperature of 9.7°C and a maximum temperature of 34.1°C. According to Figures 9(a) to (b), for example, the temperature difference in Okinawa is smaller than in Tokyo or Sapporo, and therefore it can be seen that the effect of the blending ratio of the second polyolefin resin on the thermal stress T2 of the waterproof sheet and the fixing work size is smaller. As a result, it can be seen that when the compounding ratio of the second polyolefin resin is low (for example, about 30% by weight), the fixing size can be made very small, 580 to 590 mm square or less.

[0044] 4) Weight average molecular weight / melt flow rate The weight average molecular weight of the second polyolefin resin is not particularly limited and can be changed as appropriate to suit the desired physical properties, but in terms of the mechanical properties and durability of the waterproof sheet, it is usually preferable to set it to a value within the range of 170,000 to 250,000. The reason for this is that if the weight average molecular weight of the second polyolefin resin is less than 170,000 or, conversely, exceeds 250,000, its compatibility with the first polyolefin resin decreases, and the water impermeability, mechanical properties such as tensile strength, and durability of the resulting waterproof sheet may be significantly reduced. Therefore, in the blending amount of the second polyolefin resin, it is more preferable to set the weight average molecular weight to a value within the range of 180,000 to 240,000, and even more preferably to set the value within the range of 190,000 to 220,000. For clarity, it is preferable that the weight average molecular weight of the second polyolefin resin is larger than that of the first polyolefin resin.

[0045] On the other hand, the melt flow rate (MFR) of the second polyolefin resin according to JIS K7210 is preferably set to a value within the range of 1.8 to 2.7 g / 10 min under conditions of 190° C. and a load of 2.16 kg. The reason for this is that if the melt flow rate of the first polyolefin resin is less than 1.8 g / 10 min, the flowability will be poor and the compatibility with the first polyolefin resin may decrease. On the other hand, if the melt flow rate of the first polyolefin resin exceeds 2.7 g / 10 min, the viscosity may be too low and molding may be difficult. Therefore, the melt flow rate of the second polyolefin resin is more preferably set to a value within the range of 2 to 2.6 g / 10 min, and even more preferably set to a value within the range of 2.1 to 2.5 g / 10 min.

[0046] 5) Density The density of the second polyolefin resin is not particularly limited and can be changed appropriately according to the desired physical properties. However, from the viewpoint of the strength of the waterproof sheet, it is usually 0.9 to 0.93 g / cm. 3 It is preferable to set the value within the range. The reason for this is that the density of the second polyolefin resin is 0.9 g / cm 3 The value may be less than 0.93 g / cm 3If the value exceeds this, the compatibility with the first polyolefin resin will decrease, and the water impermeability, mechanical properties such as tensile strength, and durability of the resulting waterproof sheet may be significantly reduced. Therefore, in the second polyolefin resin, the density is set to 0.905 to 0.925 g / cm 3 It is more preferable to set the value within the range of 0.91 to 0.92 g / cm 3 It is more preferable that the value is within the range of For clarity, it is preferable that the density of the second polyolefin resin is greater than the density of the first polyolefin resin.

[0047] 6) Melting point When the second polyolefin resin shows a crystalline melting peak as measured by DSC or the like, it is determined to have a melting point corresponding to the temperature of the peak value. The melting point is not particularly limited and can be changed appropriately according to the desired physical properties, but it is usually preferable to set it to a value within the range of 95 to 135°C. The reason for this is that if the melting point of the second polyolefin resin is less than 95°C or more than 135°C, the mechanical properties of the olefin resin composition may be significantly reduced, or the compatibility with the first polyolefin resin may be reduced. Therefore, the melting point of the second polyolefin resin is more preferably set to a value within the range of 105 to 132°C, and even more preferably set to a value within the range of 120 to 130°C. For clarity, it is preferable that the melting point of the second polyolefin resin is higher than that of the first polyolefin resin.

[0048] Furthermore, it is preferable that the second polyolefin resin has a melting enthalpy (ΔH) measured using DSC or the like, within a range of 110 to 150 mJ / mg. Furthermore, it is preferable that the crystallinity value of the second polyolefin resin is limited to a value within the range of 35 to 50%. It is preferable that the melting enthalpy (ΔH) and the crystallinity of the second polyolefin resin are greater than those of the first polyolefin resin.

[0049] 7) Elastic modulus (1% secant elastic modulus at 0°C) The 1% secant elastic modulus of the second polyolefin resin at 0°C is 180 to 250 N / mm 2 It is preferable to set the value within the range. The reason for this is that the modulus of elasticity of the second polyolefin resin is 180 N / mm 2 The value may be less than 250N / mm 2 If the value exceeds this, the mechanical properties and handling properties of the olefin resin composition may be significantly reduced, and the compatibility with the first polyolefin resin used in combination may be reduced. Therefore, the elastic modulus of the second polyolefin resin is set to 185 to 230 N / mm 2 It is more preferable to set the value within the range of 190 to 210 N / mm 2 It is more preferable that the value is within the range of As described above, the 1% secant elastic modulus at 0° C. was calculated from a stress-strain curve obtained by forming the second polyolefin resin into a film by a predetermined method in accordance with JIS K7127:1999. Furthermore, as shown in the characteristic curve in FIG. 11(b) described later, the 1% secant elastic modulus can be measured at a predetermined temperature (for example, 25°C), and the 1% secant elastic modulus at 0°C can be estimated in consideration of the temperature dependency, and this value can be used.

[0050] 8) Hayes Furthermore, the haze value, which is an index showing the transparency of the second polyolefin resin and conforms to JIS K7136:2000, is preferably set to a value within the range of 0.5 to 15%. The reason for this is that if the haze of the second polyolefin resin is less than 0.5% or, conversely, exceeds 15%, the transparency and mechanical properties of the olefin resin composition may be significantly reduced, and the compatibility with the first polyolefin resin used in combination may be reduced. Therefore, in the second polyolefin resin, the haze is more preferably set to a value within the range of 1 to 12%, and even more preferably to a value within the range of 2 to 10%. For clarity, it is preferable that the haze of the second polyolefin resin is smaller than the haze of the first polyolefin resin.

[0051] (3)(C) component 1) Type Component (C) is a reinforcing material (typical examples of which may be referred to as a carbon compound such as carbon black or carbon fiber), and it is preferable to blend this reinforcing material into a polyolefin resin composition which is a mixture of a first polyolefin resin and a second polyolefin resin. Therefore, typical types of component (C) are carbon compound fibers consisting of at least one of polyvinyl alcohol-based synthetic fibers, polypropylene fibers, nylon fibers, polyester fibers, rayon fibers, acrylic fibers, and carbon fibers, because they tend to exhibit excellent lightness, economy, ease of handling, mechanical strength, weather resistance, etc. Inorganic fibers such as glass fibers can also be used. Furthermore, particles or powder of a carbon compound comprising at least one of carbon nanotubes, graphene, graphite, carbon black (furnace carbon black, acetylene carbon black), etc. are preferred, and carbon black is particularly preferred, because they not only exhibit excellent lightness, economy, mixing and dispersibility, mechanical strength, weather resistance, etc., but are also easy to form into multilayers.

[0052] 2)Containing amount When the total amount of the olefin resin composition is taken as 100% by weight, it is preferable to blend a reinforcing material as component (C) in an amount within the range of 0.1 to 30% by weight. The reason for this is that if the amount of such reinforcing material is less than 0.1% by weight, the effect of improving the weather resistance and mechanical properties such as strength of the waterproof sheet may not be obtained. On the other hand, if the amount of the reinforcing material exceeds 30% by weight, the tensile strength of the resulting waterproof sheet may be significantly reduced, resulting in reduced durability against tensile stress. Therefore, the amount of such reinforcing material to be mixed is more preferably set to a value within the range of 0.5 to 15% by weight, and even more preferably set to a value within the range of 1 to 10% by weight.

[0053] 3) Average particle size / average fiber length, etc. Furthermore, when the reinforcing material is a fiber such as a carbon fiber, it is preferable that the average fiber diameter is set to a value within the range of 3 to 500 nm, and the average fiber length is set to a value within the range of 1 to 1000 μm. On the other hand, when the reinforcing material is in the form of particles or granules such as carbon particles, the average particle size is preferably in the range of 3 to 500 nm, more preferably in the range of 10 to 300 nm, and even more preferably in the range of 20 to 150 nm. The average fiber diameter and average length of fibers, or the average particle size of particles, etc., can be calculated by measuring electron micrographs and analyzing the images in accordance with JIS Z8901.

[0054] (4) Additives Furthermore, additives that may be blended as needed include various polyolefin resins other than the first polyolefin resin and the second polyolefin resin, such as high-density polyethylene, linear low-density polyethylene, high-pressure polyethylene, and polypropylene, as well as resin components such as natural rubber, synthetic rubber, and thermoplastic elastomer, as well as various fillers such as tackifiers, crosslinking agents, calcium carbonate, talc, silica, and metal fibers, antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, and colorants.

[0055] When these additives are blended, the blending amount varies depending on the type of additive, but is generally preferably in the range of 0.1 to 20% by weight, more preferably in the range of 0.5 to 10% by weight, and even more preferably in the range of 1 to 5% by weight, when the olefin resin composition is 100% by weight.

[0056] (5) Biomass content of olefin resin composition The biomass degree of the olefin resin composition obtained by mixing the first polyolefin resin and the second polyolefin resin is the same as the biomass degree of the waterproof sheet when the olefin resin composition is used as is. That is, it can be measured using a C14 accelerator mass spectrometer (AMS) in accordance with ASTM D6866. The olefin resin composition is characterized in that the biomass ratio is set to a value within the range of 5 to 40%. The reason for this is that if the biomass degree of such an olefin resin composition is less than 5%, consideration of environmental characteristics (CO2 reduction) will be lessened and may result in insufficient consideration of environmental characteristics. In particular, if the biomass degree of the olefin resin composition that makes up the water-blocking sheet is 10% or more, it can be given the biomass mark of the Japan Organic Resources Association, so it is desirable that the biomass degree of the olefin resin composition be 10% or more. On the other hand, if the biomass content of the olefin resin composition exceeds 40%, the mechanical properties such as tensile strength may be excessively reduced. Therefore, it is more preferable that the biomass ratio of such an olefin resin composition is set to a value within the range of 7 to 30%, and even more preferably to a value within the range of 8 to 20%.

[0057] (6) Thermal properties of olefin resin compositions The thermal properties of an olefin resin composition obtained by mixing a first polyolefin resin and a second polyolefin resin, such as the melting point showing the crystalline peak and the crystalline enthalpy corresponding to the area of ​​the crystalline peak, can basically be considered to be the same as the thermal properties of the waterproof sheet when the olefin resin composition is used as is as a waterproof sheet. Therefore, the thermal properties of such an olefin resin composition will be described later as a water shielding sheet.

[0058] (7) Mechanical properties of olefin resin compositions The mechanical properties of the olefin resin composition obtained by mixing the first polyolefin resin and the second polyolefin resin, such as the modulus of elasticity and tensile strength, can basically be considered to be the same as the mechanical properties of the waterproof sheet when the olefin resin composition is used as is in the waterproof sheet. Therefore, the mechanical properties of such an olefin resin composition will be described later as a waterproof sheet.

[0059] (8) Flowability of olefin resin composition With regard to the fluidity of an olefin resin composition obtained by mixing a first polyolefin resin and a second polyolefin resin, for example, the melt flow rate conforming to JIS K7210 can be considered to be the same as the melt flow rate of a waterproof sheet when the olefin resin composition is used as is. Therefore, the fluidity of such an olefin resin composition will be described later as the fluidity of the water-shielding sheet.

[0060] 5. Characteristics of waterproof sheets (1) Basic configuration 1) Single layer The waterproof sheet 10 held in place by the fixing work is a resin sheet made from a specified olefin resin composition containing a specified first olefin resin and a second olefin resin having a specified biomass content, as shown in Figure 2(a), and may basically be a single layer as long as it has specified mechanical properties (tensile strength, etc.). Such a single-layer waterproof sheet is not only relatively easy and stable to install at waste disposal sites and to manufacture, but also makes it easy to adjust the desired waterproofing properties and mechanical properties (such as tensile strength). FIG. 2(a) shows an embodiment of a waterproof sheet 10 containing a reinforcing material 10a in a predetermined first olefin resin 10b.

[0061] 2) Multilayer structure Furthermore, the waterproof sheet may be a homogeneous multilayer structure 30, as shown in Figure 2(b), in which multiple resin sheets (10, 10') derived from a specified olefin resin composition are prepared and stacked together. Waterproof sheets are made by co-extrusion molding or heat lamination, or by preparing multiple resin layers as the basic components of such waterproof sheets, usually in the range of 2 to 50 layers, and directly heat-pressing them to form a multilayer structure, or it is also preferable to indirectly laminate them via an adhesive or the like to form a homogeneous multilayer structure. Such a multi-layer waterproof sheet can be used in a wider range of applications and can more easily satisfy the various required characteristics. Therefore, when multiple waterproof sheets are stacked to form a multi-layer waterproof sheet, it is preferable that the number of layers be in the range of 2 to 50, more preferably in the range of 3 to 20, and even more preferably in the range of 4 to 10. Note that Figure 2(b) shows an embodiment of a homogeneous multilayer structure 30 formed by preparing and stacking multiple single-layer waterproof sheets 10, 10' each containing a reinforcing material in a predetermined first olefin resin 10b.

[0062] Also preferred is a heterogeneous multilayer structure 32, as shown in Figure 2(c), in which the waterproof sheet 10 of the present invention containing the reinforcing material is laminated on one side with a resin sheet not containing the reinforcing material or a heterogeneous waterproof sheet 24 containing a colorant (titanium oxide, zinc oxide, or other pigment). For example, there are waterproof sheets with a white upper layer and a black lower layer, and waterproof sheets with a heterogeneous multi-layer structure with a non-conductive upper layer and a conductive lower layer. The reason for this is that it makes it easier to distinguish between the front and back of the waterproof sheet as a whole, and if the waterproof sheet is damaged after installation, the white layer on the front surface will be scraped off, revealing the black color on the back surface, making it possible to immediately detect damage to the waterproof sheet. A waterproof sheet with a multi-layer structure that includes resin layers made of different materials like this will have even greater versatility, be able to be used in a wider range of applications, and be more likely to satisfy the various required characteristics. Figure 2(c) shows an embodiment of a heterogeneous multilayer structure 32 formed by stacking a single-layer waterproof sheet 10 containing a reinforcing material 10a in a specified first olefin resin 10b, and a waterproof sheet 24 containing a specified first olefin resin 24b and a white pigment 24a such as titanium oxide or zinc oxide. Needless to say, it is also preferable to use a multilayer structure consisting of a laminate of other resin layers, woven fabric layers, nonwoven fabric layers, metal layers, ceramic layers, or wood instead of the dissimilar waterproof sheet 24.

[0063] Figure 2(d) also shows an embodiment of a multilayer structure 34 having a three-layer sandwich structure, in which a single-layer waterproof sheet 10 containing a reinforcing material is used as the intermediate layer, and waterproof sheets 24, 24' containing a predetermined first olefin resin and a pigment such as titanium oxide are laminated on both sides of the single-layer waterproof sheet 10. On the other hand, it is also preferable to use a waterproof sheet consisting of three layers, with the resin sheet of the first embodiment used as the middle layer and resin sheets of different materials used on the front and back sides, respectively, to create a sandwich-structure waterproof sheet. Needless to say, it is also preferable to use a multilayer structure consisting of a laminate of other resin layers, woven fabric layers, nonwoven fabric layers, metal layers, ceramic layers, or wood instead of one or both of the waterproof sheets 24, 24'.

[0064] Furthermore, Figure 2(e) shows an embodiment of a five-layer multilayer structure 35 consisting of, from the bottom in the figure, a first protective mat 36, a first waterproof sheet 10, a second protective mat 36, a second waterproof sheet 10, and a shading protective mat 38. The light-shielding protective mat 38 is composed of a light-shielding layer 38b on the outer surface side and a protective mat 38a. Therefore, a multi-layer structure in which a plurality of such waterproof sheets are sandwiched between a plurality of protective mats can exhibit not only superior waterproofing properties but also excellent weather resistance and mechanical properties. However, in the case of such a five-layer multilayer structure, the interfaces may be bonded together, but by leaving them non-bonded, the effects of the shrinkage force caused by the waterproof sheet can be dispersed, and ultimately the weight and size of the fixing structure that holds them in place can be reduced.

[0065] Furthermore, since the land developed for a waste disposal site usually has a vast area, it is preferable to prepare a large number of waterproof sheets each having a specified unit area to correspond to that vast area. Therefore, as shown in Figures 1(b) to (c), it is also preferable to use a self-propelled fusion machine, a manual fusion machine, or an extrusion welding machine (not shown) to partially overlap the edges of waterproof sheets 10 and 10' having a predetermined unit area and heat-weld them at multiple locations such as joints 22 and 22' to form a large-area waterproof sheet that exhibits a predetermined level of waterproofing.

[0066] (2) Tensile strength The tensile strength of the waterproof sheet is 950N / cm, which is calculated by dividing the tensile strength (unit: N / cm) conforming to JIS K6251:2017 based on the Planning, Design and Management Guidelines for the Development of Final Waste Disposal Sites (2010 revised edition, National Urban Cleaning Conference, hereinafter referred to as the Management Guidelines) by the thickness of the waterproof sheet. 2 It is characterized in that the value is equal to or greater than this. The reason for this is that the tensile strength of such a waterproof sheet is 950N / cm 2If the value is less than this, the durability against tensile stress is low and the waterproof sheet is prone to damage. Therefore, the tensile strength of the waterproof sheet is 950N / cm 2 As described above, it is also preferable to provide a tensile strength adjustment layer made basically of the same type of material on one or both sides of the waterproof sheet. In addition, the tensile strength of the waterproof sheet is 950N / cm 2 If this is the case, there is also the advantage that the requirement of tensile strength not divided by the thickness of the waterproof sheet of 140 N / cm or more, which is stated in the management guidelines mentioned above for synthetic resin-based, medium-elasticity types, is fully met. In the waterproof sheet of the present invention, the stress reaches its maximum just before the test piece breaks, and therefore the maximum stress value corresponds to the tensile strength.

[0067] However, if the tensile strength of such a waterproof sheet is made too high, the sheet will have excessive rigidity, making it difficult to handle, and the range of selectable types of olefin resin compositions that can be used may become excessively narrow. Therefore, the tensile strength of such a waterproof sheet is 1500 to 6000 N / cm 2 It is preferable to set the value within the range of 2800 to 5000 N / cm 2 It is more preferable to set the value within the range of 3800 to 4500 N / cm 2 It is more preferable that the value is within the range of

[0068] Here, referring to FIG. 3(b), the relationship between the biomass content (%) of the waterproof sheet and the tensile strength will be explained. That is, the horizontal axis of FIG. 3(b) shows the biomass content (%) of the waterproof sheet, and the vertical axis shows the tensile strength value of the waterproof sheet. As shown in the characteristic curve in Figure 3(b), up to a biomass content (%) of approximately 5 to 20% of the waterproof sheet, the tensile strength of the waterproof sheet tends to remain almost unchanged as the blend ratio increases. Next, as the biomass content (%) increases from over 20% up to about 40%, there is a tendency for the tensile strength of the waterproof sheet to decrease slightly. Furthermore, when the biomass content (%) of the waterproof sheet exceeds 40%, the tensile strength of the waterproof sheet clearly tends to decrease as the content increases. Therefore, by limiting the biomass content (%) of the waterproof sheet to a value within a predetermined range, it is possible to obtain a waterproof sheet with a tensile strength equal to or greater than a predetermined value.

[0069] (3) Joint shear strength It is preferable that the waterproof sheet has a joint shear strength of 80 N / cm or more in accordance with JIS K6850:1999. The reason for this is that if the joint shear strength is less than 80 N / cm, the strength of the joint will be low and there will be a high possibility that the joint will break due to the tensile stress generated within the repository. However, if the design is such that the value of the shear strength of the joint between such waterproof sheets is excessively large, the range of selectable types of usable olefin resin compositions may become excessively narrow. Therefore, it is more preferable that the joint shear strength of such a waterproof sheet be set to a value within the range of 80 to 250 N / cm, and even more preferable that it be set to a value within the range of 100 to 220 N / cm. Furthermore, if the joint shear strength of such waterproof sheets is 80 N / cm or more, it has the advantage of meeting the synthetic resin-based, medium elasticity type requirements of the management guidelines mentioned above.

[0070] The shear strength of the joint was measured as follows. That is, the two obtained waterproof sheets were overlapped by 100 mm in accordance with JIS K6850:1999, and the joints were heat-sealed using a self-propelled fusion machine (manufacturer: Leister, product name: Twiny) under conditions of a fusion temperature of 460°C, a speed of 2.0 m / min, a pressure of 580 N, and an air temperature of 31°C, to obtain test specimens that conformed to the standard. Next, the maximum load until the test piece broke was determined using a tensile tester at a tension speed of 50 mm / min at room temperature (23°C), and the shear strength of the joint was calculated.

[0071] Here, referring to Figure 3(c), the relationship between the biomass content (%) of the waterproof sheet and the shear strength of the joints of the waterproof sheet will be explained. That is, the horizontal axis of Figure 3(c) shows the biomass content (%) of the waterproof sheet, and the vertical axis shows the shear strength (N / cm) of the joints of the waterproof sheet. As shown by the characteristic curve in Figure 3(c), as the biomass content (%) of the waterproof sheet increases, the value of the waterproof sheet's joint shear strength tends to gradually decrease, albeit slightly, by up to 15% or less. Therefore, by limiting the biomass content (%) of the waterproof sheet to a value within a predetermined range, it is possible to obtain a waterproof sheet with a predetermined joint shear strength (80 N / cm) or higher. Conversely, it can be said that the lower the biomass content (%) of the waterproof sheet, the greater the value of the joint shear strength of the waterproof sheet.

[0072] Furthermore, referring to FIG. 4, the relationship between the blending amount of the second polyolefin resin in the olefin resin composition and the biomass content of the water-shielding sheet will be explained. That is, the amount of the second polyolefin resin in the olefin resin composition has a strong correlation with the biomass content of the water-shielding sheet. Therefore, if the blending amount of the second polyolefin resin is, for example, 40% by weight or more, the biomass degree of the waterproof sheet can be set to a predetermined value of 30% or more. Therefore, judging from the characteristic curve of Figure 4, it can be said that by adjusting the amount of the second polyolefin resin, the biomass content of the waterproof sheet can be set within the desired range, and ultimately, the tensile strength of the waterproof sheet, as shown in Figure 3(b), and the joint shear strength of the waterproof sheet, as shown in Figure 3(c), can be easily adjusted to values ​​within the specified ranges.

[0073] (4) Thickness The thickness of the waterproof sheet, measured in accordance with JIS K6250, is preferably set to a value within the range of 0.5 to 30 mm. The reason for this is that if the thickness is less than 0.5 mm, the mechanical properties such as tensile strength and handling properties may be significantly reduced, or the manufacturing costs may increase due to yield factors. On the other hand, if the thickness exceeds 30 mm, the ability to conform to the surface and handling will decrease, and furthermore, the manufacturing costs will increase excessively in relation to the amount of raw materials used, which may be economically disadvantageous. Also, as the thickness increases, the unit weight increases, which decreases transportability and workability. Therefore, it is more preferable to set the thickness of the waterproof sheet to a value within the range of 1 to 10 mm, and even more preferable to set it to a value within the range of 1.5 to 5 mm. In order for such a waterproof sheet to satisfy the above-mentioned management requirements, it is preferable that the thickness of the waterproof sheet be 1.5 mm or more.

[0074] (5) Water-impermeable The waterproof sheet has a moisture permeability (g / m) conforming to JIS Z0208. 2 / hr) can be used as an index for evaluation. That is, the moisture permeability is 0.1 mg / m 2 By setting the value to be not more than 1 / hr, it is possible to obtain a waterproof sheet that exhibits good waterproofing. The reason for this is that the moisture permeability is 0.1 mg / m 2 If the value exceeds 1 / hr, it may not be possible to achieve sufficient water impermeability. On the other hand, if the moisture permeability is too low, the range of raw material selection may be too narrow, or handling may be impaired, or production costs may increase, which may be economically disadvantageous. Therefore, the moisture permeability of the waterproof sheet is set to 0.0001 to 0.05 mg / m 2 / hr, and more preferably 0.001 to 0.01 mg / m 2 It is more preferable to set the value in the range of 1 / hr.

[0075] In addition, the water impermeability of the waterproof sheet is determined by the moisture permeability (g / m) that conforms to the above-mentioned management guidelines. 2 The hydraulic conductivity (cm / sec) obtained from the above formula (·hr) can be used as an index for evaluation. That is, the hydraulic conductivity is 1×10 -9 By setting the value to be equal to or less than cm / sec, a waterproof sheet can be obtained that exhibits good waterproofing. The reason for this is that the permeability coefficient is 1×10 -9 If the value exceeds cm / sec, it may not be possible to achieve sufficient water impermeability. On the other hand, if the hydraulic conductivity is too small, the range of raw material options becomes too narrow, or the manufacturing costs increase, which may be economically disadvantageous. Therefore, the permeability coefficient of the waterproof sheet is set to 1 x 10 -14 ~1×10 -9 It is more preferable to set the value in the range of 1×10 cm / sec. -13 ~1×10 -9 It is more preferable to set the value in the range of cm / sec.

[0076] (6) Elastic modulus (1% secant elastic modulus) The waterproof sheet conforms to JIS K7127:1999 and has a 1% secant elastic modulus of 150 to 350 N / mm at 0°C. 2 It is preferable to set the value within the range. The reason for this is that the 1% secant elastic modulus of such a waterproof sheet is 150N / mm 2 This is because the strength may be weak if the value is less than this. Conversely, 350N / mm 2 If the value exceeds this, the rigidity becomes excessively large and handling may become difficult. Therefore, the 1% secant elastic modulus of the waterproof sheet should be 180 to 250 N / mm 2 It is more preferable to set the value within the range of 200 to 240 N / mm 2 It is more preferable that the value is within the range of Furthermore, by setting the 1% secant elastic modulus of the waterproof sheet to a value within this range, it not only has excellent mechanical properties, but also makes it easier to accurately adjust the tensile strength of the waterproof sheet and the tension of the waterproof sheet when installed on a slope within a specified range.

[0077] Furthermore, since the modulus of elasticity of the second polyolefin resin is greater than the modulus of elasticity of the polyolefin resin of the first polyolefin resin that constitutes the waterproof sheet, if the proportion of the second polyolefin resin in the second polyolefin resin is excessively high, the modulus of elasticity may become excessively high.

[0078] Furthermore, at waste disposal sites, weights called anchors 16 are used to secure the waterproof sheet 10 to the slope, as shown in Figures 1(a) and (d), and materials such as concrete are generally used for the anchors. It is known that there is a correlation between the amount of concrete used as fixing work and the value of the 1% secant modulus of elasticity of the waterproof sheet, and the smaller the 1% secant modulus of elasticity, the less concrete tends to be used. Therefore, by blending the second polyolefin resin with the first polyolefin resin described above and balancing the two to reduce the 1% secant elastic modulus of the waterproof sheet, it may be possible to reduce the amount of concrete used in the fixing work.

[0079] Here, referring to FIG. 5(a), the relationship between the biomass ratio of a waterproof sheet and the elastic modulus of the waterproof sheet (1% secant elastic modulus at 0°C) will be explained. That is, the horizontal axis of FIG. 5(a) shows the biomass content (%) of the waterproof sheet, and the vertical axis shows the elastic modulus of the waterproof sheet. As shown by the characteristic curve in Figure 5(a), when the biomass content (%) of the waterproof sheet is in the range of 0 to 40%, the elastic modulus of the waterproof sheet tends to increase as the biomass content (%) increases. Furthermore, even when the biomass ratio (%) of the waterproof sheet is in a range of values ​​greater than 40%, as the biomass ratio (%) increases, the elastic modulus value increases, but the rate of increase tends to decrease slightly. Therefore, it can be understood that by limiting the biomass content (%) of a waterproof sheet to a value within a predetermined range, a waterproof sheet having an elastic modulus below a predetermined value can be obtained. In addition, the elastic modulus (1% secant elastic modulus at 0°C) is expected to decrease in value at ambient temperatures, for example, room temperature (23°C) in actual use, but it is known to change with a certain correlation. If this is the case, there is no doubt that by limiting the biomass content (%) of the waterproof sheet to a value within a predetermined range, it is possible to adjust the elastic modulus to correspond to changes in different ambient temperatures.

[0080] Furthermore, referring to FIG. 5(b), the relationship between the 1% secant elastic modulus of the waterproof sheet at 0°C and the tensile strength of the waterproof sheet will be explained. That is, the horizontal axis of Figure 5(b) shows the 1% secant elastic modulus of the waterproof sheet, and the vertical axis shows the tensile strength of the waterproof sheet when the biomass content is 5% or more. From the characteristic curve in FIG. 5(b), it can be seen that there is an excellent correlation between the value of the 1% secant elastic modulus and the value of the tensile strength. Therefore, it can be said that by limiting the value of the 1% secant elastic modulus, it becomes easier to control the value of the tensile strength within a predetermined range. Conversely, it is understood that by limiting the value of the tensile strength to a value within a predetermined range, the value of the 1% secant modulus of elasticity can be controlled more precisely, albeit indirectly.

[0081] (7) Tensile elongation Based on the above-mentioned management guidelines, it is preferable that the average tensile elongation in the longitudinal and transverse directions of the waterproof sheet (hereinafter sometimes simply referred to as tensile elongation) conforming to JIS K6251:2017 is within the range of 500% to less than 750%. The reason for this is that if the tensile elongation is less than 500%, the mechanical strength such as tensile strength will decrease, and the material may be more susceptible to damage when ground subsidence or the like occurs. On the other hand, if the tensile elongation of such a waterproof sheet is 750% or more, the range of choices for the types of olefin resin compositions that can be used may become excessively narrow. Therefore, it is more preferable that the tensile elongation of such a waterproof sheet is set to a value within the range of 520 to 700%, and even more preferable that it is set to a value within the range of 540 to 670%.

[0082] (8) Bending resistance Furthermore, it is preferable that the water shielding sheet has a bending resistance (sometimes referred to as Gurley bending resistance) in accordance with JIS L1096:2010 of a value within the range of 140 mN to less than 230 mN. The reason for this is that if the bending resistance is less than 140 mN, the mechanical strength such as tensile strength may decrease, resulting in vulnerability to impact. On the other hand, if the bending resistance is 230 mN or more, the range of selection of the types of olefin resin compositions that can be used may become excessively narrow. Therefore, it is more preferable that the bending resistance of such a waterproof sheet is set to a value within the range of 150 to 220 mN, and even more preferable that it is set to a value within the range of 170 to 210 mN. The bending resistance was measured in accordance with the Gurley method specified in JIS L1096:2010, and the bending resistance (mN) of the obtained waterproof sheet was measured three times on each side, and the average value obtained was used as the bending resistance (mN) of the waterproof sheet. More specifically, six test pieces measuring 89 mm in length and 25 mm in width were prepared in the longitudinal direction of the waterproof sheet. The bending resistance (mN) of three of the test pieces was measured on the front surface and the other three on the back surface at room temperature (23°C), and the average value was used as the bending resistance (mN) of the waterproof sheet.

[0083] (9) Thermal stress T2 Furthermore, it is preferable that the thermal stress (T2) of the waterproof sheet calculated by the following formula (1) is set to a value within the range of 1000 to 10000 N / m.

[0084]

number

[0085] The reason for this is that by calculating the thermal stress (T2) of the waterproof sheet and specifically limiting it, the occurrence of thermal stress in the fixing work can be suppressed, and ultimately its size and weight can be reduced. Therefore, as described above, it is preferable to set the thermal stress (T2) to a value within the range of 1000 to 10000 N / m, more preferably within the range of 1300 to 8000 N / m, and even more preferably within the range of 1500 to 7000 N / m.

[0086] Furthermore, the minimum temperature tb used when calculating the thermal stress T2 of the waterproof sheet is preferably set in accordance with the temperature of the area where it will be used, but it is usually preferable to set it to a value within the range of -45 to 5°C. The reason for this is that by calculating the thermal stress T2 of the waterproof sheet based on such minimum temperatures, it becomes easier to provide waterproof sheets with safe and reliable fixing structures that are suitable for each region of Japan (for example, Tokyo, Sapporo, Okinawa), even taking into account the drop in winter temperatures due to recent environmental changes. Therefore, it is preferable that the waterproof sheet be configured for use in areas with a minimum air temperature tb of -45 to 5°C, more preferably for use in areas with a minimum air temperature tb of -30 to 0°C, and even more preferably for use in areas with a minimum air temperature tb of -20 to -5°C.

[0087] Furthermore, the maximum temperature ta used when calculating the thermal stress T2 of the waterproof sheet is preferably set to match the temperature of the area where it will be used, but it is usually preferable to set it to a value within the range of 30 to 50°C. The reason for this is that by calculating the thermal stress T2 of the waterproof sheet based on such maximum temperatures, it becomes easier to provide waterproof sheets with fixing works that are suitable for any part of Japan (for example, Tokyo, Sapporo, Okinawa), even taking into account the rise in summer temperatures due to recent environmental changes. Therefore, it is preferable that the waterproof sheet be configured for use in areas with a maximum temperature ta of 30 to 50°C, more preferably for use in areas with a maximum temperature ta of 33 to 48°C, and even more preferably for use in areas with a maximum temperature ta of 35 to 45°C.

[0088] In addition, the cross-sectional area A (m 2 ) can be calculated by multiplying the thickness (m) measured in accordance with JIS K6250:2019 by the width (m) of the waterproof sheet. Specifically, the cross-sectional area of ​​a waterproof sheet is usually 0.0003 to 0.01 m when the width is 1 m. 2 It is preferable to set the value within the range. The reason for this is that by using such a cross-sectional area, the thermal stress T2 can be calculated more accurately, and therefore the fixing size can be adjusted more accurately. Therefore, the cross-sectional area A of the waterproof sheet is set to 0.0004 to 0.005 m 2 It is more preferable to set the value within the range of 0.0005 to 0.0025 m 2 It is more preferable that the value is within the range of

[0089] Furthermore, the temperature dependence index α of the elastic modulus of the waterproof sheet used when calculating the thermal stress T2 of the waterproof sheet can be determined from the relationship between the elastic modulus measured under five different temperature environments: -25°C, 0°C, 20°C, 40°C, and 60°C in a tensile test using dumbbell-shaped test pieces and rectangular test pieces in accordance with JIS K7139:2009. Specifically, it is usually preferable to set the temperature dependency index α(−) of the elastic modulus of the waterproof sheet to a value within the range of 0.003 to 0.03. The reason for this is that by using such a temperature-dependent index, the waterproof sheet can be used more generally, regardless of the temperature, etc., of the location where it is used. Therefore, it is more preferable that the temperature dependence exponent α of the elastic modulus of the waterproof sheet is set to a value within the range of 0.005 to 0.02, and even more preferable that it is set to a value within the range of 0.008 to 0.015. Here, the temperature dependence index α is, for example, EPDM: approximately 0.01, PE (including thermoplastic elastomer): approximately 0.013, PP (including thermoplastic elastomer): approximately 0.013, HDPE: approximately 0.01, PVC: approximately 0.034, and TPU: approximately 0.0056, as examples of waterproof sheet materials.

[0090] Furthermore, the coefficient of linear expansion β (1 / ° C.) of the waterproof sheet used in calculating the thermal stress T2 of the waterproof sheet can be determined by a thermal expansion coefficient test in accordance with JIS K7197:1991. Specifically, the linear expansion coefficient β of the waterproof sheet is usually set to 0.1 × 10 -4 ~3×10 -4 It is preferable to set the temperature within the range of 1 / °C. The reason for this is that by using such a linear expansion coefficient, the waterproof sheet can be used more generally, regardless of the temperature and other factors of the place where it is used. Therefore, the linear expansion coefficient β of the waterproof sheet is set to 0.4 × 10 -4 ~2.5×10 -4 It is more preferable to set the value within the range of 0.8×10 -4 ~2×10 -4 It is more preferable that the value is within the range of

[0091] The number n of waterproof sheets is preferably selected appropriately depending on the purpose of use of the waterproof sheets and the installation location, but is usually preferably two or more. The reason for this is that by using this number of sheets, even if a hole is made in the upper layer of waterproof sheet by a sharp object or the like, the layer below can maintain the specified waterproof effect. Therefore, although two waterproof sheets will generally provide sufficient waterproofing, it is more preferable to use two to ten sheets, and even more preferable to use three to five sheets, taking into account the possibility of them being torn. Depending on the type of substrate, it may be preferable to use only one sheet.

[0092] (10) Fixture size It is also known that when laying a waterproof sheet on a slope, the waterproof sheet and a weight called a fixing work are fitted into a rectangular trench on the upstream side to fix the waterproof sheet. In this case, it is known that the size of the fixed work can be calculated from the tension T1 (N / m) acting downward on the slope due to the weight of the waterproof sheet, the thermal stress T2 (N / m) caused by the waterproof sheet thermally shrinking due to temperature changes, the first retraction force T3-1 (N / m) caused by compression due to the load of the cargo on the waterproof sheet, and the second retraction force T3-2 (N / m) caused by compression due to the increased load of heavy machinery working on the cargo. That is, the anchorage size (m) can be calculated from the following formula (2) as the size of the anchorage having a weight equal to the total tension (N / m) of the waterproof sheet. The size of the fixed work is defined as the length of one side of a square formed by cutting the fixed work with a plane perpendicular to the width direction, assuming that the width of the fixed work is 1 m.

[0093]

number

[0094] Specifically, the size of the anchorage is determined by using concrete blocks (specific gravity: 23 kN / m 3 ) is preferably 0.7 m or less. The reason for this is that by using such a fixing size, the fixing size can be directly understood, and therefore the fixing size can be more easily reduced. Therefore, it is more preferable that the size of the fixed structure is 0.65 m or less, and even more preferable that it is 0.63 m or less. On the other hand, if the fixing work is too small, the influence of factors other than the overall tension of the waterproof sheet will become greater, and problems such as misalignment may occur. Therefore, the fixing work size is preferably 0.3 m or more, more preferably 0.35 m or more, and even more preferably 0.4 m or more. The method for determining the size of the fixings will be explained in detail below.

[0095] First, the total tension (N / m) of the waterproof sheet acting on the fixing work can be calculated from the following formula (2-1) by multiplying each of the values ​​of T1, T2, T3-1, and T3-2 by a predetermined influence ratio.

[0096]

number

[0097] Furthermore, T1 is the tension of the waterproof sheet per meter width that acts on the fixed structure due to the weight of the waterproof sheet, acting downward on the slope. Specifically, T1 (N / m) can be calculated from the weight of the waterproof sheet per 1 m of width W1 (N / m), the coefficient of friction μ1 between the waterproof sheet and the member directly below the waterproof sheet, and the inclination angle θ (°) of the slope using the following formula (2-2).

[0098]

number

[0099] Therefore, T1 is preferably 300 N / m or less, more preferably 200 N / m or less, and even more preferably 100 N / m or less. If T1 is a negative value, no tension is applied, so calculations are performed assuming T1 to be 0.

[0100] Furthermore, T2 is the tension equivalent to the thermal stress of the waterproof sheet per meter width that acts on the fixing structure when the waterproof sheet thermally shrinks due to temperature changes. Specifically, T2 (N / m) can be calculated from the above-mentioned equation (1) relating to thermal stress. Therefore, as described above, it is preferable to set the thermal stress (T2) to a value within the range of 1000 to 10000 N / m, more preferably within the range of 1300 to 8000 N / m, and even more preferably within the range of 1500 to 7000 N / m.

[0101] Furthermore, T3-1 is the tension equivalent to the pull-in force of the waterproof sheet per meter of width (hereinafter sometimes referred to as the first pull-in force) acting on the fixed structure due to compression by the load of the cargo on the waterproof sheet. In other words, T3-1 is the tension equivalent to the retraction force of the waterproof sheet that acts on the fixing structure when the waterproof sheet is compressed by placing waste or other cargo on it, and the surrounding parts pull back the compressed part. Here, although there are various methods for calculating T3-1, it has been found that in any case, differences in the calculation method have almost no effect on the calculation of the fixed work size. For example, T3-1 (N / m) can be calculated from the weight of the load per 1 m of width W2 (N / m), the coefficient of friction μ2 between the waterproof sheet and the component directly below the waterproof sheet, the inclination angle θ (°) of the slope, and the angle δ (°) between the waterproof sheet and the load, using the following formula (2-3):

[0102]

number

[0103] Therefore, the first retraction force T3-1 is preferably set to a value within the range of 5000 to 15000 N / m, more preferably within the range of 6000 to 12000 N / m, and even more preferably within the range of 7000 to 10000 N / m. Note that δ is the angle between the waterproof sheet and the cargo, and since cargo such as waste is dumped along the slope, this value is very small, so tan δ can be calculated as essentially 0.

[0104] Here, it is known that even if the same load is applied to the second, third and subsequent layers from the surface of the waterproof sheet, the pulling force generated by the load gradually decreases. Therefore, when the waterproof sheet is made up of multiple layers, it is preferable to calculate the burden rate for the lower layer by multiplying it by 0.3 to 0.6. Therefore, as an example, it is preferable that the contribution rate for the second layer be 0.45, and the contribution rates for the third layer and thereafter be 0.3.

[0105] Furthermore, T3-2 is the tension equivalent to the pull-in force of the waterproof sheet per meter of width (hereinafter sometimes referred to as the second pull-in force) acting on the fixed work due to compression caused by the weight of the heavy machinery on the load. In other words, T3-2 is the tension equivalent to the retraction force of the waterproof sheet that acts on the fixed work when the waterproof sheet is compressed by the approach of heavy machinery such as a bulldozer working on a load, and the surrounding parts pull back the compressed part. Here, although there are various methods for calculating T3-2, it has been found that in any case, differences in the calculation method have almost no effect on the calculation of the fixed work size. Specifically, T3-2 (N / m) can be calculated from the weight of the load per 1 m of width W3 (N / m), the coefficient of friction μ3 between the waterproof sheet and the component directly below the waterproof sheet, the inclination angle θ (°) of the slope, and the angle δ (°) between the waterproof sheet and the load, using the following formula (2-4):

[0106]

number

[0107] Therefore, the second retraction force T3-2 is preferably set to a value within the range of 500 to 3000 N / m, more preferably to a value within the range of 800 to 2500 N / m, and even more preferably to a value within the range of 1000 to 2000 N / m. Note that δ is the angle between the waterproof sheet and the cargo, and since cargo such as waste is dumped along the slope, this value is very small, so tan δ can be calculated as essentially 0.

[0108] [Second embodiment] The second embodiment is a method for manufacturing a waterproof sheet derived from an olefin resin composition, which is laid on at least the slope of a waste disposal site and whose edges are held in place by fixing works, and is characterized by including the following steps (1) to (2). Step (1): A step of mixing an olefin resin composition containing a first polyolefin resin containing petroleum-derived ethylene units and a second polyolefin resin containing plant-derived ethylene units, and adjusting the biomass ratio in accordance with ASTM D6866 to a value within a range of 5 to 40% as configuration (A). Step (2): A step of producing a waterproof sheet derived from an olefin resin composition and satisfying the following requirements (B) to (D). (B) The 1% secant elastic modulus (E0) at 0°C measured in accordance with JIS K7127:1999 is 150 to 350 N / mm 2 The value is in the range. (C) Permeability coefficient is 1 × 10 -9 The value is less than cm / sec. (D) Tensile strength measured in accordance with JIS K6251:2017 is 950N / cm 2 The above values. Hereinafter, the method for manufacturing the waterproof sheet of the second embodiment will be specifically described with reference to the drawings as appropriate.

[0109] 1.Process (1) (1) Step (1) is a step of preparing a predetermined olefin resin composition. That is, an olefin resin composition containing a first polyolefin resin containing petroleum-derived ethylene units as the first polyolefin resin and a second polyolefin resin containing plant-derived ethylene units as the second polyolefin resin is prepared by manufacturing each of them or purchasing a commercially available product. Next, these raw material resins and the like are weighed and mixed in a predetermined ratio, and the biomass ratio according to ASTM D6866 is adjusted to a value within the range of 5 to 40%. The details of the first polyolefin resin containing petroleum-derived ethylene units as the first polyolefin resin and the second polyolefin resin containing plant-derived ethylene units as the second polyolefin resin can be the same as those described in the first embodiment, and therefore will not be described again.

[0110] (2) In addition, in step (1), when a reinforcing material is contained as component (C), it is preferable to set the amount of the reinforcing material to a value within the range of 0.1 to 30% by weight, when the total amount of the olefin resin composition is taken as 100% by weight. The reason for this is that by incorporating a specified amount of reinforcing material in this manner, the weather resistance and mechanical properties of the waterproof sheet can be further improved, and it may become easier to adjust them to within a specified range. In addition, by incorporating a predetermined amount of such reinforcing material, it becomes easy to color the resulting waterproof sheet black or gray, which may improve the decorativeness, light-shielding properties, etc. of the waterproof sheet.

[0111] 2.Process (2) Step (2) is a step of forming a waterproof sheet having predetermined properties from a predetermined olefin resin composition. That is, a waterproof sheet having the predetermined properties can be stably formed by at least one of known film-forming methods such as an extruder, a film forming machine, a T-die extruder, a press, a casting method, or an inflation molding machine.

[0112] 3. Other processes (1) Inspection process for waterproofing of waterproof sheets The obtained waterproof sheet was measured for moisture permeability (g / m2), which is an index of waterproofing, in accordance with JIS Z0208. 2 ·hr), calculating the water permeability coefficient k (cm / sec) from the water vapor permeability by a method described later, and inspecting that the water permeability coefficient is within a predetermined range. That is, for the obtained waterproof sheet, the permeability coefficient is, for example, 1 × 10 -9It is preferable to confirm that the value is equal to or less than cm / sec. In addition to or instead of the water permeability coefficient, which is an index of water impermeability, moisture permeability can also be used as an index of water impermeability.

[0113] (2) Winding and cutting process of waterproof sheet When the obtained waterproof sheet is in a long shape, it is preferable to include a step of winding it into a roll. It is also preferable to include a cutting step of punching the obtained waterproof sheet into a predetermined shape. The direction in which the waterproof sheet is wound by the winding machine is sometimes referred to as the longitudinal direction, and the direction perpendicular to the longitudinal direction is sometimes referred to as the width direction.

[0114] (3) Evaluation process of the mechanical properties of the waterproof sheet It is preferable to include a step of evaluating the mechanical properties of the obtained waterproof sheet. That is, for the obtained waterproof sheet, the tensile strength (unit: N / cm) conforming to JIS K6251:2017 was measured and divided by the thickness of the waterproof sheet to obtain the tensile strength derived from the material. For example, 2 It is preferable to confirm and evaluate that the value is equal to or greater than this. The resulting waterproof sheet has a 1% secant elastic modulus of 150 to 350 N / mm2 measured in accordance with JIS K7127:1999. 2 It is preferable to confirm and evaluate that the value is within the range.

[0115] (4) Lamination process of other sheets The resulting waterproof sheet may include a lamination step for processing the front and back surfaces thereof. That is, for example, the method may include a step of laminating the obtained waterproof sheet with multiple sheets of the same or different type using heat welding or adhesive to form a waterproof sheet with a multi-layer structure. It is also preferable to laminate the resulting waterproof sheet with other resin layers, metal layers, ceramic layers, nonwoven fabrics, or wood using an adhesive or the like to form a multilayer structure.

[0116] (5) Evaluation process of thermal stress of waterproof sheet It is preferable to include a step of evaluating the thermal stress T2 of the obtained waterproof sheet. That is, it is preferable to confirm and evaluate that the thermal stress T2 calculated by the formula (1) is a value within the range of 1000 to 10000 N / m. The reason for this is that by calculating the thermal stress (T2) of the waterproof sheet and specifically limiting it, the occurrence of thermal stress in the fixing work can be suppressed, and ultimately its size and weight can be reduced. Therefore, it is more preferable to set the thermal stress (T2) of the water-shielding sheet to a value within the range of 1300 to 8000 N / m, and even more preferable to set it to a value within the range of 1500 to 7000 N / m.

[0117] (6) Installation process of the fixing work It is preferable that the subsequent process include laying the obtained waterproof sheet against a slope, digging a rectangular trench on the upstream side of the slope, and fitting the specified fixing work and the waterproof sheet into the rectangular trench to fix the waterproof sheet. [Example]

[0118] The present invention will be described in more detail below based on examples.

[0119] [Example 1] 1. Manufacturing of waterproof sheets (1) Preparation of olefin resin composition As the first polyolefin resin, a first polyolefin resin containing petroleum-derived ethylene units (commercially available product: Evolue SP1022 (density: 0.905 to 0.912 g / cm) manufactured by Prime Polymer Co., Ltd.) was used. 3 , MFR: 1.5 to 2.5 g / 10 min (190° C., 2.16 kg load), melting point: 97° C., 113.6° C., biomass content: 0%, resin color: colorless and transparent, referred to as TYP1 in Table 1) was prepared.

[0120] Similarly, as the second polyolefin resin, a second polyolefin resin containing plant-derived ethylene units (commercially available product: SLH218 manufactured by Braskems (density: 0.916 g / cm)) was used. 3 Comonomer: 1-hexene, MFR: 2.3 g / 10 min (190°C, 2.16 kg load), melting point: 126°C, biomass content: 84%, resin color: colorless and transparent, referred to as TYP2 in Table 1) was prepared.

[0121] Next, the first polyolefin resin and the second polyolefin resin were weighed and mixed so that the ratio by weight of the first polyolefin resin to the second polyolefin resin was 90:10, so that the biomass content of the olefin resin composition would be 8.4%. Furthermore, a carbon black-containing masterbatch (Tokyo Ink & Chemicals, Inc., PEX 9BB047 BLACK, average particle size 10-300 nm, carbon black concentration 40%) was uniformly mixed to a total amount of 100% by weight of the olefin resin composition to give an amount of 6.7% by weight, thereby obtaining an olefin resin composition containing a reinforcing material.

[0122] (2) Formation of waterproof sheet Using a T-die coater, discharge temperature: 200°C, pressure: 6 kg / cm 2 Under the above conditions, a long sheet (single layer) having an average thickness of 1.5 mm was produced using the prepared olefin resin composition as a raw material.

[0123] 2. Evaluation of waterproof sheets (1) Water-proof (rating 1) The moisture permeability, which is an index of water impermeability, of the obtained waterproof sheets was measured in accordance with JIS Z0208:1976, and the water permeability coefficient k (cm / sec) was calculated using the following formula (3), and evaluated according to the following criteria.

[0124]

number

[0125] ◎: Permeability coefficient is 1×10 -12 The value is less than cm / sec. ○: Permeability coefficient is 1×10-12 cm / sec~1×10 -11 The value is less than cm / sec. △: Permeability coefficient is 1×10 -11 cm / sec~1×10 -9 The value is less than cm / sec. ×: Permeability coefficient is 1×10 -9 The value is greater than cm / sec.

[0126] (2) Environmental characteristics (rating 2) When the CO2 emissions of the first polyolefin resin, which contains petroleum-derived ethylene units, are taken as 100%, the CO2 emissions of the second polyolefin resin, which contains plant-derived ethylene units, are 30%, and it has been found that the second polyolefin resin can reduce CO2 emissions by 70%. Therefore, it is possible to calculate the amount of CO2 emissions and their reduction rate from the weight ratio of the first polyolefin resin to the second polyolefin resin, and the calculated reduction rate of CO2 emissions was evaluated according to the following criteria. ◎: The CO2 emission reduction rate is 15% or more. ○: The CO2 emission reduction rate is 7% or more. △: The CO2 emission reduction rate is 5% or more. ×: The reduction rate of CO2 emissions is less than 5%.

[0127] (3) 1% secant elastic modulus at 0°C (Evaluation 3) The obtained waterproof sheet was punched out into rectangular test pieces (2.5 cm wide, 16 cm long) to provide test pieces for the 1% secant elastic modulus at 0° C. A tensile test was performed on the obtained test pieces in the longitudinal direction in accordance with JIS K7127 using a tensile tester (Strograph VG10E, manufactured by Toyo Seiki Seisaku-sho, Ltd.) at a tensile speed of 1 mm / min, a grip distance of 100 mm, and a temperature of 0° C., and an SS curve was obtained. At this time, the stress when such 1% strain (chuck movement distance 1 mm) was applied was calculated, and the 1% secant elastic modulus at 0°C was calculated by dividing this value by the cross-sectional area and strain of the test piece, as shown in the following formula (4). The same measurement was repeated three times, and the average value was taken as the value of the 1% secant elastic modulus at 0°C.

[0128]

number

[0129] (4) Thermal stress T2 in the fixing work (rating 4) The thermal stress T2 in the fixing work was calculated from the 1% secant elastic modulus at 0°C of the obtained waterproof sheet according to formula (1), and evaluated according to the following criteria. At this time, when calculating the thermal stress T2, the cross-sectional area A is set to 0.0015m 2 The temperature dependence exponent α is set to 0.0109, and the linear expansion coefficient β is set to 1.95×10 -4 / °C, with the maximum temperature set at 45°C and the minimum temperature set at -20°C. ◎: The thermal stress in the fixing work is within the range of 1500 to 7000 N / m. ◯: The thermal stress in the fixing work is within the range of 1300 to 8000 N / m, which is outside the range of ⊚ above. △: The thermal stress in the fixing work is a value within the range of 1000 to 10000 N / m, and is outside the range of ◯. ×: The thermal stress in the fixing work is less than 1000 N / m or more than 10000 N / m.

[0130] (5) Fixture size (rating 5) The size of the anchoring work was calculated from the thermal stress T2 in the anchoring work that holds the obtained waterproof sheet, etc., according to formula (2), and evaluated according to the following criteria. At this time, when calculating the size of the fixing work, the slope angle θ is set to 26.6°, the friction coefficient μ1 to μ3 of the polyester fiber material directly below the waterproof sheet is set to 0.51, and the weight W1 of the waterproof sheet is set to 14.1 N / m 2 The weight of the load W2 is 13200N / m2 The weight of the heavy equipment, W3, is 2300N / m 2 The calculation was made assuming the burden rate for the second layer to be 0.45. ◎: The fixed work size is within the range of 0.4 to 0.63 m. ◯: The fixed work size is within the range of 0.35 to 0.65 m, and is outside the range of the above ◎. △: The fixing size is within the range of 0.3 to 0.7 m, and is outside the range of ◯. ×: The fixed work size is less than 0.3 m or more than 0.7 m.

[0131] (6) Tensile strength (rating 6) The obtained waterproof sheet was punched out three times in each of the longitudinal and width directions of the waterproof sheet using a dumbbell No. 3 shape specified in accordance with JIS K6251:2017 to obtain waterproof sheet test pieces. Next, the tensile tester was used at a tensile speed of 50 mm / min, a grip distance of 60 mm, and room temperature (23°C). The maximum load (P A ) and calculate the tensile strength (T A ) and then divide that value by the thickness of the waterproof sheet to obtain the tensile strength (T B The average value in the longitudinal and transverse directions was calculated as the tensile strength (T av ) was evaluated. T A =P A / W T A : Tensile strength (unit: N / cm) P A : Maximum load (unit: N) W: width of test piece (0.5 cm) T B =T A / t T B : Tensile strength (unit: N / cm 2 ) t: Thickness of the waterproof sheet (unit: cm)

[0132] (7) Joint shear strength (rating 7) The obtained waterproof sheet was heat-sealed using a self-propelled fusion machine (Twiny, manufactured by Leister) under conditions of a fusion temperature of 460°C, a pressure of 580 (N), and a speed of 2.0 m / min at an air temperature of 31°C. The fused waterproof sheet was then punched out into strips 2.5 cm wide and 16 cm long, with the sheet joint positioned in the center of the length of the test piece, to prepare test pieces for joint shear strength.

[0133] Next, the test piece was subjected to a tensile test in accordance with JIS K6850:1999 at room temperature (23°C), a tensile speed of 50 mm / min, and the maximum load (P c ) and calculate the joint shear force (T c The measurement was carried out three times, and the average value was used as the value of the joint shear strength. T c =P c / W T c : Joint shear strength (unit: N / cm) P c : Maximum load (unit: N) W: width of test piece (2.5 cm)

[0134] [Examples 2 to 3] In Examples 2 and 3, waterproof sheets were manufactured and evaluated in the same manner as in Example 1, except that the blending ratios of the petroleum-derived first polyolefin resin (TYP1) and the plant-derived second polyolefin resin (TYP2) containing ethylene units were 80:20 and 70:30 by weight, and the biomass content of the olefin resin composition was 16.8% and 25.2%.

[0135] [Comparative Example 1] In Comparative Example 1, waterproof sheets were manufactured and evaluated in the same manner as in Example 1, except that only the petroleum-derived first polyolefin resin (TYP1) was used and no plant-derived second polyolefin resin containing ethylene units was used at all.

[0136] Comparative Example 2 In addition, in Comparative Example 2, waterproof sheets were manufactured and evaluated in the same manner as in Example 1, except that only the second polyolefin resin (TYP2) containing plant-derived ethylene units was used, and no petroleum-derived first polyolefin resin was used at all.

[0137] Comparative Example 3 In addition, in Comparative Example 3, a first polyolefin resin (TYP1) containing petroleum-derived ethylene units and a second polyolefin resin (TYP2) also containing petroleum-derived ethylene units were used as the first polyolefin resin, and waterproof sheets were manufactured and evaluated in the same manner as in Example 1, except that the blending ratio was 50:50.

[0138] [Table 1] [Industrial Applicability]

[0139] According to the waterproof sheet of the present invention, at least components (A) to (D) are made of an olefin resin composition having a specified biomass content, and the 1% secant elastic modulus at 0°C, the thermal stress (T2) in the fixing work, the weight in the fixing work, etc. are controlled to be within predetermined ranges, thereby solving the problems of the past. In other words, the present invention makes it possible to provide a waterproof sheet that is excellent in contradictory properties such as environmental properties and tensile strength, and an efficient method for manufacturing such a waterproof sheet.

[0140] Therefore, the waterproof sheets of the present invention are expected to be used in a wide range of applications, including not only waterproof sheets used in industrial waste disposal, etc., but also as spring water blocking sheets used in situations where water is rising, such as at tunnel construction sites and dam sites, rainwater penetration prevention sheets used on building roofs and house roofs, general waterproof sheets, and even bag-shaped products made from them. [Explanation of symbols]

[0141] 10, 10': Water-resistant sheet 10a: Carbon black 10b: Olefin resin 12: Waste 14: Waste disposal site development 16:Fixing work 22, 22′: Joint 24, 24´: Different waterproof sheets 24a: Pigment 24b: First olefin resin 30: Homogeneous multilayer structure 32: Heterogeneous multilayer structure 34: Multilayer sandwich structure

Claims

1. A waterproof sheet derived from an olefin resin composition, which is laid on at least the slope of a waste disposal site and whose edges are held in place by fixing works, and which satisfies the following configurations (A) to (D). (A) The biomass content of the olefin resin composition, as determined in accordance with ASTM D6866, is within the range of 5 to 40%. (B) 1% secant elastic modulus (E) at 0°C measured in accordance with JIS K7127:1999 0 ) is 150 to 350 N / mm 2 The value is in the range. (C) The coefficient of permeability is 1 x 10 -9 The value is less than cm / sec. (D) Tensile strength measured in accordance with JIS K6251:2017 is 950 N / cm 2 The above values.

2. When the thermal stress defined by the following formula in the fixing work that holds the waterproof sheet is T2, T2 is set to 1000 to 10000 (N / m 2 2. The waterproof sheet according to claim 1, characterized in that the value is within the range of . [Equation 1]

3. A waterproof sheet as described in claim 1, characterized in that the minimum air temperature used when calculating the thermal stress (T2) in the waterproof sheet is set to a value within the range of -45 to 5°C.

4. A waterproof sheet as described in claim 1, characterized in that the maximum temperature used when calculating the thermal stress (T2) in the waterproof sheet is set to a value within the range of 30 to 50°C.

5. The water-shielding sheet according to claim 1, characterized in that the olefin resin composition contains, as a first polyolefin resin, an olefin copolymer of petroleum-derived ethylene and an α-olefin having 3 to 12 carbon atoms, and as a second polyolefin resin, an olefin copolymer of plant-derived ethylene and an α-olefin having 3 to 12 carbon atoms.

6. A waterproof sheet as described in claim 1, characterized in that it has a multilayer structure having at least a waterproof sheet on the front side and a waterproof sheet on the back side, wherein the waterproof sheet on the front side is of a predetermined color and the waterproof sheet on the back side is of a color different from the predetermined color.

7. 2. The waterproof sheet according to claim 1, which is placed between a light-shielding protective mat and a protective substrate and constitutes a part of a waterproof multilayer structure.

8. A method for producing a waterproof sheet derived from an olefin resin composition, which is laid on at least the slope of a waste disposal site and whose edges are held in place by fixing works, comprising the following steps (1) to (2): Step (1): A step of mixing the olefin resin composition containing a first polyolefin resin containing petroleum-derived ethylene units and a second polyolefin resin containing plant-derived ethylene units, and adjusting the biomass ratio in accordance with ASTM D6866 to a value within a range of 5 to 40% as structure (A). Step (2): A step of producing a waterproof sheet derived from the olefin resin composition and satisfying the following requirements (B) to (D). (B) 1% secant elastic modulus (E) at 0°C measured in accordance with JIS K7127:1999 0 ) is 150 to 350 N / mm 2 The value is in the range. (C) The coefficient of permeability is 1 x 10 -9 The value is less than cm / sec. (D) Tensile strength measured in accordance with JIS K6251:2017 is 950 N / cm 2 The above values.

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