High-impermeability wear-resistant composite geomembrane and preparation method thereof

Abstract

The invention provides a high-impermeability and wear-resistant composite geomembrane and a preparation method thereof. The technical problem that collaborative optimization of impermeability and wear resistance of existing commercially available geomembranes is difficult to achieve at the same time is solved. The composite geomembrane is of a four-layer structure and is sequentially connected with a wear-resistant protective layer, a bonding transition layer, a core impervious layer and a base material reinforcing layer from top to bottom. The wear-resistant protective layer is prepared from the following raw materials in parts by weight: 80-87 parts of high-density polyethylene, 10-18 parts of silicon carbide wear-resistant filler, 1-2 parts of an antioxidant and 0.5-1 part of an ultraviolet light absorber; the bonding transition layer is prepared from the following raw materials in parts by weight: 90 to 95 parts of ethylene-vinyl acetate copolymer and 5 to 10 parts of maleic anhydride grafted polyethylene; the core anti-seepage layer is prepared from the following raw materials in parts by weight: 85 to 88 parts of linear low-density polyethylene, 5 to 8 parts of nano montmorillonite anti-seepage filler and 5 to 8 parts of carbon black master batch; the base material reinforcing layer is a polypropylene filament spun-bonded needle-punched geotextile; the invention further discloses a preparation method of the composite geomembrane. The material can be widely applied to the technical field of building materials.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of building materials, in particular to a high-anti-permeation wear-resistant composite geomembrane and a preparation method thereof. BACKGROUND

[0002] The geomembrane is a waterproof barrier type material taking high-molecular polymers as basic raw materials, and can be divided into single geomembrane and composite geomembrane in terms of structural composition, and is widely applied to the anti-permeation engineering in the fields of water conservancy, environmental protection, transportation, mining and building.

[0003] The current commercially available geomembrane still has technical bottlenecks in the synergistic optimization of anti-permeation performance and wear resistance, and it is difficult to achieve both: the single geomembrane (for example, polyethylene geomembrane) has good anti-permeation ability, but the surface hardness is low, and the geomembrane is easily damaged under the friction in the construction process or the extrusion of sharp materials in the landfill; and the composite geomembrane can improve the wear resistance to a certain extent, but the bonding strength between the geomembrane and the membrane layer is insufficient, and delamination phenomenon occurs after long-term soaking, and finally the overall anti-permeation performance is invalid. SUMMARY The purpose of the application is to solve the above technical problems, provide a high-anti-permeation wear-resistant composite geomembrane and a preparation method thereof, reduce the anti-permeation coefficient, improve the wear resistance and the interlayer bonding strength, and meet the harsh use requirements of different engineering scenes.

[0004] Therefore, the application provides a high-anti-permeation wear-resistant composite geomembrane, and the composite geomembrane has a four-layer structure, and the wear-resistant protective layer, the bonding transition layer, the core anti-permeation layer and the base material reinforcing layer are sequentially connected from top to bottom.

[0005] The preparation raw materials of the wear-resistant protective layer are high-density polyethylene 80-87 parts, silicon carbide wear-resistant filler 10-18 parts, antioxidant 1-2 parts and ultraviolet absorber 0.5-1 part according to weight.

[0006] The preparation raw materials of the bonding transition layer are ethylene-vinyl acetate copolymer 90-95 parts and maleic anhydride grafted polyethylene 5-10 parts according to weight.

[0007] The preparation raw materials of the core anti-permeation layer are linear low-density polyethylene 85-88 parts, nano-montmorillonite anti-permeation filler 5-8 parts and carbon black master batch 5-8 parts according to weight.

[0008] The base material reinforcing layer is polypropylene filament spun-bonded needle-punched geotextile.

[0009] Preferably, the total thickness of the composite geomembrane is controlled at 2.0-3.5mm, and the thickness ratio of the wear-resistant protective layer, the bonding transition layer, the core impermeable layer, and the substrate reinforcing layer is (15-20):(5-8):(40-50):(25-30).

[0010] Preferably, the wear-resistant protective layer, the bonding transition layer, and the core impermeable layer are combined into a three-layer plastic film melt through hot-pressing and curing on the surface of the substrate reinforcing layer after being compounded by multi-layer co-extrusion casting.

[0011] Preferably, the particle size of the silicon carbide wear-resistant filler in the wear-resistant protective layer is 5-10μm, the antioxidant is antioxidant 1010 or antioxidant 1076, and the ultraviolet absorber is ultraviolet absorber UV-531 or ultraviolet absorber UV-326; the VA content of the ethylene-vinyl acetate copolymer in the bonding transition layer is 18%-22%; and the warp breaking strength of the substrate reinforcing layer is ≥80kN / m, and the weft breaking strength is ≥70kN / m.

[0012] A method for preparing a high-impermeable wear-resistant composite geomembrane according to any one of the above, characterized in that the steps include: Step S1. High-density polyethylene, silicon carbide wear-resistant filler, antioxidant, and ultraviolet absorber are weighed according to the weight parts and mixed and granulated to obtain wear-resistant protective layer masterbatch, which is ready for use; Step S2. Ethylene-vinyl acetate copolymer and maleic anhydride grafted polyethylene are weighed according to the weight parts and mixed and granulated to obtain bonding transition layer masterbatch, which is ready for use; Step S3. Linear low-density polyethylene, nano-montmorillonite impermeable filler, and carbon black masterbatch are weighed according to the weight parts and mixed and granulated to obtain core impermeable layer masterbatch, which is ready for use; Step S4. The substrate reinforcing layer is subjected to plasma surface treatment to obtain a plasma surface-treated substrate reinforcing layer, which is ready for use; Step S5. The wear-resistant protective layer masterbatch obtained in step S1, the bonding transition layer masterbatch obtained in step S2, and the core impermeable layer masterbatch obtained in step S3 are respectively combined into a three-layer plastic film melt through three-layer co-extrusion casting, and then hot-pressed and cured on the surface of the substrate reinforcing layer, and after cooling, a high-impermeable wear-resistant composite geomembrane is obtained.

[0013] Preferably, in step S1, high-density polyethylene, silicon carbide wear-resistant filler, antioxidant, and ultraviolet absorber are weighed according to the weight parts, uniformly mixed at a temperature of 100-110℃, and then fed into a double-screw extruder, with the temperature control ranges of the respective sections of the double-screw extruder being: zone 1 140-150℃, zone 2 160-170℃, zone 3 175-185℃, and die head 180-190℃. After melting and extrusion, the particles are cooled and cut, with the particle size being controlled at 2-4mm, to obtain wear-resistant protective layer masterbatch.

[0014] Preferably, in step S2, ethylene-vinyl acetate copolymer and maleic anhydride-grafted polyethylene are weighed according to weight parts, mixed evenly at a temperature of 85-95℃, and then fed into a twin-screw extruder. The temperature control range of each section of the twin-screw extruder is as follows: Zone 1 120-130℃, Zone 2 140-150℃, Zone 3 155-165℃, and Die Head 160-170℃. After melt extrusion, the mixture is cooled and pelletized, with the particle size controlled at 2-4mm, to obtain the bonding transition layer masterbatch.

[0015] Preferably, in step S3, linear low-density polyethylene, nano-montmorillonite impermeable filler, and carbon black masterbatch are weighed according to weight parts, mixed evenly at a temperature of 95-105℃, and then fed into a twin-screw extruder. The temperature control range of each section of the twin-screw extruder is as follows: Zone 1 130-140℃, Zone 2 150-160℃, Zone 3 165-175℃, and Die Head 170-180℃. After melt extrusion, the material is cooled and pelletized, with the particle size controlled at 2-4mm, to obtain the core impermeable layer masterbatch.

[0016] Preferably, in step S4, the substrate reinforcement layer is fed into a plasma surface treatment machine, the activation power is controlled at 300-400W, the treatment time is 10-15s, and the conveying speed of the substrate reinforcement layer during treatment is 2-3m / min, so as to obtain a plasma-treated substrate reinforcement layer.

[0017] Preferably, in step S5, the wear-resistant protective layer masterbatch obtained in step S1, the bonding transition layer masterbatch obtained in step S2, and the core impermeable layer masterbatch obtained in step S3 are respectively fed into three independent barrels of a three-layer co-extrusion casting machine. After being melted and plasticized by their respective screws, they are extruded through a composite die to form a three-layer plastic film melt. The extrusion temperature of the wear-resistant protective layer melt is controlled at 195-200℃, the extrusion temperature of the bonding transition layer melt is controlled at 185-190℃, and the extrusion temperature of the core impermeable layer melt is controlled at 180-185℃. The three-layer plastic film melt is then cooled after being hot-pressed and solidified on the surface of the substrate reinforcement layer to complete the composite molding. The pressure of the composite pressure roller is controlled at 0.3-0.5MPa, and the temperature of the cooling roller is controlled at 25-30℃ to obtain a high impermeability and wear-resistant composite geomembrane.

[0018] This invention provides a high impermeability and wear-resistant composite geomembrane and its preparation method, with the following beneficial effects: (1) Excellent impermeability: The nano-montmorillonite impermeable filler added to the core impermeable layer of this invention can form a "layered barrier structure", making the impermeability coefficient of the composite geomembrane ≤1.0×10 -13 cm / s, far superior to traditional PE geomembranes (typically with a permeability coefficient of 1.0×10 cm / s). -10 cm / s); (2) Significantly improved wear resistance: In the wear-resistant protective layer of this invention, HDPE and silicon carbide wear-resistant filler work together. According to Taber wear resistance test, its mass loss is 0.06-0.08g, which is far less than 0.3g. The wear resistance is 2-3 times that of traditional composite geomembrane. (3) Strong and reliable interlayer bonding: The ethylene-vinyl acetate copolymer (EVA) and maleic anhydride grafted polyethylene compound system in the bonding transition layer of this invention, combined with the plasma surface activation treatment of the substrate reinforcement layer, makes the interlayer bonding strength 6.8-7.2 N / cm, which is much higher than 3.5 N / cm, effectively solving the problem of easy delamination of traditional geomembranes after long-term immersion; (4) Wide range of applicable scenarios: The raw material ratio can be flexibly adjusted according to the needs of different scenarios such as landfills, water conservancy projects, and tailings ponds to achieve precise matching of impermeability, wear resistance, and strength performance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the high impermeability and wear-resistant composite geomembrane of the present invention.

[0021] The markings in the diagram are: 1. Wear-resistant protective layer, 2. Adhesive transition layer, 3. Core impermeable layer, 4. Substrate reinforcement layer. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0023] Unless otherwise specified, the methods used in this invention are conventional methods; the raw materials and apparatus used are conventional commercially available products unless otherwise specified.

[0024] In a specific embodiment of the present invention, the information regarding the manufacturers of the raw materials used is as follows: High-density polyethylene (HDPE) was purchased from Qilu Branch of China Petroleum & Chemical Corporation, with grade HD5502XA and melt index of 0.9 g / 10 min; The silicon carbide wear-resistant filler was purchased from Shandong Jinmeng New Material Co., Ltd., with a particle size of 5-10μm and a purity of ≥99%. Antioxidant 1010 was purchased from Beijing Jiyi Chemical Co., Ltd., industrial grade, purity ≥98%; The ultraviolet absorber UV-531 was purchased from Changzhou Wujin Hengye Chemical Co., Ltd., industrial grade, purity ≥99%; The ethylene-vinyl acetate copolymer (EVA) was purchased from Beijing Dongfang Petrochemical Co., Ltd., with a VA content of 18%-22% and a grade of 18-2. Maleic anhydride-grafted polyethylene was purchased from Nanjing Sutai New Materials Co., Ltd., with a grafting rate of 0.8%-1.2%, and the grade was PE-g-MAH-01. Linear low-density polyethylene (LLDPE) was purchased from Dushanzi Petrochemical Branch of China National Petroleum Corporation, with the grade DFDA-7042 and a melt index of 2.0 g / 10 min. The nano-montmorillonite seepage barrier was purchased from Zhejiang Fenghong New Material Co., Ltd., with a particle size of 50-100nm and an organic modification rate of ≥95%. The carbon black masterbatch was purchased from Shanghai Color Masterbatch Co., Ltd., with a carbon black content of 25% and a PE carrier. Polypropylene filament spunbond needle-punched geotextile was purchased from Shandong Lude New Material Co., Ltd., with a warp tensile strength ≥80kN / m, a weft tensile strength ≥70kN / m, and a basis weight of 300g / m. 2 .

[0025] like Figure 1 As shown, the high impermeability and wear-resistant composite geomembrane prepared in Examples 1, 2, and 3 has a four-layer structure, consisting of a wear-resistant protective layer 1, a bonding transition layer 2, a core impermeable layer 3, and a substrate reinforcement layer 4 connected sequentially from top to bottom. The wear-resistant protective layer 1 is the outermost layer, providing resistance to friction and puncture. The bonding transition layer 2 connects the wear-resistant protective layer 1 and the core impermeable layer 3 to prevent delamination; The core anti-seepage layer 3 serves as an intermediate layer and has a core anti-seepage function; The substrate reinforcement layer 4 is the innermost layer, providing strength support.

[0026] The total thickness and the thickness of each layer of the high impermeability and wear-resistant composite geomembrane of this invention are shown in Table 1: Table 1. Total thickness and layer thickness of high impermeability and wear-resistant composite geomembrane

[0027] Therefore, the total thickness of the composite geomembrane is 2.0-3.5mm, and the thickness ratio of the wear-resistant protective layer 1, bonding transition layer 2, core impermeable layer 3, and substrate reinforcement layer 4 is (15-20): (5-8): (45-50): (24-30).

[0028] The raw material formulas for the high impermeability and wear-resistant composite geomembrane described in Examples 1, 2, and 3 are shown in Table 2: (The unit of content of each raw material in Table 2 is: parts by weight) Table 2. Formulations of the wear-resistant protective layer, bonding transition layer, and core impermeable layer of high-permeability and wear-resistant composite geomembrane.

[0029] The preparation method of the high impermeability and wear-resistant composite geomembrane described in Examples 1, 2, and 3 involves forming a three-layer plastic film melt by multi-layer co-extrusion casting of a wear-resistant protective layer 1, an adhesive transition layer 2, and a core impermeable layer 3, and then hot-pressing it onto the surface of the substrate reinforcement layer 4. The steps include: Step S1. Weigh out high-density polyethylene, silicon carbide wear-resistant filler, antioxidant 1010, and ultraviolet absorber UV-531 according to the weight parts. Mix them evenly at a temperature of 100-110℃ and then feed them into a twin-screw extruder. The temperature control range of each section of the twin-screw extruder is as follows: Zone 1 140-150℃, Zone 2 160-170℃, Zone 3 175-185℃, and Die Head 180-190℃. After melt extrusion, the mixture is water-cooled and pelletized, with the particle size controlled at 2-4mm, to obtain wear-resistant protective layer masterbatch 1 for later use.

[0030] Step S2. Weigh out the ethylene-vinyl acetate copolymer and maleic anhydride-grafted polyethylene according to the weight parts, mix them evenly at a temperature of 85-95℃, and then feed them into a twin-screw extruder. The temperature control range of each section of the twin-screw extruder is as follows: Zone 1 120-130℃, Zone 2 140-150℃, Zone 3 155-165℃, and Die Head 160-170℃. After melt extrusion, the mixture is air-cooled and pelletized, with the particle size controlled at 2-4mm, to obtain the bonding transition layer 2 masterbatch for later use.

[0031] Step S3. Weigh linear low-density polyethylene, nano-montmorillonite impermeable filler, and carbon black masterbatch according to the weight parts. Mix them evenly at a temperature of 95-105℃ and then feed them into a twin-screw extruder. The temperature control range of each section of the twin-screw extruder is as follows: Zone 1 130-140℃, Zone 2 150-160℃, Zone 3 165-175℃, and Die Head 170-180℃. After melt extrusion, the mixture is water-cooled and pelletized, with the particle size controlled at 2-4mm, to obtain the core impermeable layer 3 masterbatch for later use.

[0032] Step S4. Feed the polypropylene filament spunbond needle-punched geotextile into a plasma surface treatment machine. Control the activation power at 300-400W and the treatment time at 10-15s. During the treatment, the conveying speed of the polypropylene filament spunbond needle-punched geotextile is 2-3m / min. Obtain the plasma-treated substrate reinforcement layer 4 for later use.

[0033] Step S5. The wear-resistant protective layer 1 masterbatch obtained in step S1, the bonding transition layer 2 masterbatch obtained in step S2, and the core anti-permeability layer 3 masterbatch obtained in step S3 are respectively fed into the three independent barrels of the three-layer co-extrusion casting machine. After being melted and plasticized by their respective screws, they are extruded through a composite die to form a three-layer plastic film melt. The extrusion temperature of the wear-resistant protective layer 1 melt is controlled at 195-200℃, the extrusion temperature of the bonding transition layer 2 melt is controlled at 185-190℃, and the extrusion temperature of the core anti-permeability layer 3 melt is controlled at 185-190℃. The temperature is controlled at 180-185℃; the three-layer plastic film melt is solidified on the surface of the substrate reinforcement layer 4 by hot pressing and then cooled, so that the three-layer plastic film melt and polypropylene filament spunbonded needle-punched geotextile are tightly bonded under the action of composite pressure rollers, and then quickly shaped by cooling rollers to complete the composite molding. The pressure of the composite pressure roller is controlled at 0.3-0.5MPa, and the temperature of the cooling roller is controlled at 25-30℃, respectively, to obtain the high impermeability and wear-resistant composite geomembrane described in Examples 1, 2 and 3.

[0034] The high impermeability and wear-resistant composite geomembranes prepared in Examples 1, 2, and 3 were tested for impermeability, wear resistance, and interlayer bonding performance, respectively. The test results are shown in Table 3. Table 3 Performance test results of high impermeability and wear-resistant composite geomembrane

[0035] Based on the test results shown in Table 3, preliminary analysis indicates that: (1) Excellent impermeability: The nano-montmorillonite impermeable filler added to the core impermeable layer 3 of this invention can form a "layered barrier structure", making the impermeability coefficient of the composite geomembrane ≤1.0×10 -13 cm / s, far superior to traditional PE geomembranes (typically with a permeability coefficient of 1.0×10 cm / s). -10 cm / s); (2) Significantly improved wear resistance: In the wear-resistant protective layer 1 of this invention, HDPE and silicon carbide wear-resistant filler work together. According to Taber wear resistance test, its mass loss is 0.06-0.08g, which is much lower than 0.3g. The wear resistance is 2-3 times that of traditional composite geomembrane. (3) Strong and reliable interlayer bonding: The EVA and maleic anhydride grafted polyethylene compound system in the bonding transition layer 2 of this invention, combined with the plasma surface activation treatment of the substrate reinforcement layer 4, makes the interlayer bonding strength 6.8-7.2 N / cm, which is much higher than 3.5 N / cm, effectively solving the problem of easy delamination of traditional geomembranes after long-term immersion; (4) Wide range of applicable scenarios: The raw material ratio can be flexibly adjusted according to the needs of different scenarios such as landfills, water conservancy projects, and tailings ponds to achieve precise matching of impermeability, wear resistance, and strength performance.

[0036] It should be noted that in the above embodiments 1-3: (1) Step S1. Weigh out high-density polyethylene, silicon carbide wear-resistant filler, antioxidant 1010 and ultraviolet absorber UV-531 according to the weight parts and put them into a high-speed mixer. Mix for 15-20 minutes at a speed of 800-1000r / min and a temperature of 100-110℃ to achieve uniform mixing. (2) Step S2. Weigh out the ethylene-vinyl acetate copolymer and maleic anhydride grafted polyethylene according to the weight parts and put them into a high-speed mixer. Mix them for 12-15 minutes at a speed of 700-800 r / min and a temperature of 85-95℃ to achieve uniform mixing.

[0037] (3) Step S3. Weigh the linear low-density polyethylene, nano-montmorillonite anti-seepage filler and carbon black masterbatch according to the weight parts and put them into a high-speed mixer. Mix for 18-22 minutes at a speed of 900-1000r / min and a temperature of 95-105℃ to achieve uniform mixing.

[0038] (4) Steps S1 and S3 use water-cooled pelletizing, and step S2 uses air-cooled pelletizing. Other cooling methods can also be used for pelletizing.

[0039] (5) Antioxidant 1010 can be replaced by other antioxidants such as antioxidant 1076.

[0040] (6) UV absorber UV-531 can be replaced by other UV absorbers such as UV-326.

[0041] (7) Step S5. After the three-layer plastic film melt is hot-pressed and solidified on the surface of the substrate reinforcement layer 4, it is cooled to complete the composite molding. The operator can perform post-processing according to the actual situation. For example, the geomembrane after composite molding is pulled smoothly by a traction machine, and the traction force is controlled at 5-8kN; then the irregular edges on both sides are cut off by a disc-type edge trimmer, and the cutting width is controlled at 5-10mm; finally, it is wound up by an automatic winding machine. Note that the winding speed is synchronized with the traction speed, which is 3-5m / min, and finally a high impermeability and wear-resistant composite geomembrane is obtained.

[0042] (8) The weight parts mentioned in the above embodiments of the present invention refer to weight units, such as grams, kilograms, etc. The weight parts of each raw material mentioned in the embodiments are the same unit, such as all in grams or all in kilograms. The weight parts listed are only used to indicate the weight distribution ratio between each raw material. The weight parts of all components can be increased or decreased proportionally according to the values ​​described in the embodiments.

[0043] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A high impermeable and abrasion resistant geomembrane characterized in that, The composite geomembrane has a four-layer structure, and sequentially connected from top to bottom are a wear-resistant protective layer, a bonding transition layer, a core impermeable layer, and a substrate reinforcing layer; The preparation raw materials of the wear-resistant protective layer are high-density polyethylene 80-87 parts, silicon carbide wear-resistant filler 10-18 parts, antioxidant 1-2 parts, and ultraviolet absorber 0.5-1 part by weight; The preparation raw materials of the bonding transition layer are ethylene-vinyl acetate copolymer 90-95 parts and maleic anhydride grafted polyethylene 5-10 parts by weight; The preparation raw materials of the core impermeable layer are linear low-density polyethylene 85-88 parts, nano-montmorillonite impermeable filler 5-8 parts, and carbon black master batch 5-8 parts by weight; The substrate reinforcing layer is a polypropylene filament spun-bonded needle-punched geotextile.

2. The high impermeable and wear resistant composite geomembrane according to claim 1, characterized in that, The total thickness of the composite geomembrane is controlled to be 2.0-3.5 mm, and the thickness ratio of the wear-resistant protective layer, the bonding transition layer, the core impermeable layer, and the substrate reinforcing layer is (15-20):(5-8):(40-50):(25-30).

3. The high impermeable and wear resistant composite geomembrane according to claim 1, characterized in that, The wear-resistant protective layer, the bonding transition layer, and the core impermeable layer are combined into a three-layer plastic film melt through multi-layer co-extrusion flow casting, and then solidified on the surface of the substrate reinforcing layer through hot pressing.

4. The high impermeable and wear resistant composite geomembrane according to claim 1, characterized in that, The particle size of the silicon carbide wear-resistant filler of the wear-resistant protective layer is 5-10 μm, the antioxidant is antioxidant 1010 or antioxidant 1076, and the ultraviolet absorber is ultraviolet absorber UV-531 or ultraviolet absorber UV-326; the VA content of the ethylene-vinyl acetate copolymer of the bonding transition layer is 18%-22%; and the warp breaking strength of the substrate reinforcing layer is ≥80 kN / m, and the weft breaking strength is ≥70 kN / m.

5. A method of preparing a high impermeable wear resistant composite geomembrane as claimed in any one of claims 1 to 4, characterized by the steps of Comprise: Step S1. high-density polyethylene, silicon carbide wear-resistant filler, antioxidant, and ultraviolet absorber are weighed according to weight parts, mixed and granulated to obtain wear-resistant protective layer master batch, ready for use; Step S2. ethylene-vinyl acetate copolymer and maleic anhydride grafted polyethylene are weighed according to weight parts, mixed and granulated to obtain bonding transition layer master batch, ready for use; Step S3. linear low-density polyethylene, nano-montmorillonite impermeable filler, and carbon black master batch are weighed according to weight parts, mixed and granulated to obtain core impermeable layer master batch, ready for use; Step S4. the substrate reinforcing layer is subjected to plasma surface treatment to obtain a plasma surface treated substrate reinforcing layer, ready for use; Step S5. the wear-resistant protective layer master batch obtained in step S1, the bonding transition layer master batch obtained in step S2, and the core impermeable layer master batch obtained in step S3 are combined into a three-layer plastic film melt through three-layer co-extrusion flow casting, and then solidified on the surface of the substrate reinforcing layer through hot pressing, and the high impermeability and wear resistance composite geomembrane is obtained after cooling.

6. The method of claim 5, wherein, In the step S1, high density polyethylene, silicon carbide wear-resistant filler, antioxidant, ultraviolet absorber are weighed and mixed uniformly at a temperature of 100-110 ℃, and then sent to a double screw extruder, the temperature control ranges of each section of the double screw extruder are as follows: 140-150 ℃ for the first section, 160-170 ℃ for the second section, 175-185 ℃ for the third section, and 180-190 ℃ for the die head, and then the molten extrusion is cooled and granulated, and the particle size is controlled to be 2-4 mm, thereby obtaining the wear-resistant protective layer master batch.

7. The method of claim 5, wherein, In the step S2, ethylene-vinyl acetate copolymer and maleic anhydride grafted polyethylene are weighed and mixed uniformly at a temperature of 85-95 ℃, and then sent to a double screw extruder, the temperature control ranges of each section of the double screw extruder are as follows: 120-130 ℃ for the first section, 140-150 ℃ for the second section, 155-165 ℃ for the third section, and 160-170 ℃ for the die head, and then the molten extrusion is cooled and granulated, and the particle size is controlled to be 2-4 mm, thereby obtaining the bonding transition layer master batch.

8. The method of claim 5, wherein, In the step S3, linear low density polyethylene, nano-montmorillonite impermeable filler and carbon black master batch are weighed and mixed uniformly at a temperature of 95-105 ℃, and then sent to a double screw extruder, the temperature control ranges of each section of the double screw extruder are as follows: 130-140 ℃ for the first section, 150-160 ℃ for the second section, 165-175 ℃ for the third section, and 170-180 ℃ for the die head, and then the molten extrusion is cooled and granulated, and the particle size is controlled to be 2-4 mm, thereby obtaining the core impermeable layer master batch.

9. The method of claim 5, wherein, In the step S4, the substrate reinforcing layer is sent to a plasma surface treatment machine, the activation power is controlled to be 300-400 W, the treatment time is 10-15 s, and the conveying speed of the substrate reinforcing layer during the treatment is 2-3 m / min, thereby obtaining the plasma surface treated substrate reinforcing layer.

10. The method according to any one of claims 5 to 9, characterized in that, In the step S5, the wear-resistant protective layer master batch obtained in the step S1, the bonding transition layer master batch obtained in the step S2, and the core impermeable layer master batch obtained in the step S3 are respectively put into three independent barrels of a three-layer co-extrusion casting machine, and then molten and plasticized through respective screws, and then extruded through a composite die to form a three-layer plastic film melt, wherein the extrusion temperature of the wear-resistant protective layer melt is controlled to be 195-200 ℃, the extrusion temperature of the bonding transition layer melt is controlled to be 185-190 ℃, and the extrusion temperature of the core impermeable layer melt is controlled to be 180-185 ℃; and then the three-layer plastic film melt is cured through hot pressing on the surface of the substrate reinforcing layer, and then cooled, thereby completing the composite molding, wherein the pressure of the composite pressing roller is controlled to be 0.3-0.5 MPa, and the temperature of the cooling roller is controlled to be 25-30 ℃, thereby obtaining the high impermeable and wear-resistant composite geomembrane.

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