Special material for outer wall of PE double-wall corrugated pipe and preparation method of special material

Abstract

The invention discloses a special material for the outer wall of a PE double-wall corrugated pipe and a preparation method of the special material, and belongs to the technical field of polymer composite materials. 10 to 15 parts of sepiolite loaded with rare earth ions; 15 to 20 parts of talcum powder; 10 to 20 parts of calcium carbonate; 1 to 3 parts of nano titanium dioxide; 2 to 6 parts of POSS-based siloxane; 3-6 parts of a lubricant; the preparation raw materials of modified recycled polyethylene comprise recycled polyethylene, acrylic acid, glycidyl methacrylate and dicumyl peroxide, the preparation raw materials of POSS-based siloxane comprise octa-aminopropyl polysilsesquioxane and aldehyde siloxane, and the formula cost is reduced by using a broken material of flower B and a reclaimed material of blue barrel as main raw materials; a new polyethylene resin material is not needed, and through a modification process, the material performance meets the use requirements of the double-wall corrugated pipe, and the pipe performance is excellent.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer composite materials, and particularly relates to a special material for the outer wall of a PE double-wall corrugated pipe and a preparation method thereof. Background Art

[0002] Double-wall PE corrugated pipes are widely used in urban drainage networks and other fields. Traditionally, the outer layer of double-wall corrugated pipes requires high-density polyethylene (HDPE) resin, which is relatively expensive. With the rapid development of the plastics industry, the recycling of waste plastics has gained widespread attention as a measure to conserve energy and protect the environment. Using recycled high-density polyethylene flakes as raw material is becoming a growing trend in the plastic pipe industry.

[0003] Currently, recycled high-density polyethylene flakes primarily refer to colored, crystalline HDPE, such as detergent bottles and Wahaha bottles. Typical processing methods for recycled HDPE on the market include sorting, crushing, cleaning, separation, and drying. Metallic impurities are difficult to completely remove, and the flakes lack the toughness to meet the high-strength requirements of large-diameter pipes. Direct use can compromise the pipe's mechanical properties and production stability, and can even lead to production quality issues such as holes, delamination, and brittleness in the outer wall of double-wall corrugated pipes.

[0004] Currently, double-wall corrugated pipes made from recycled polyethylene (especially recycled high-density polyethylene (HDPE)) suffer from poor oxidation resistance. This is primarily reflected in substandard oxidation induction time (200°C), which leads to aging and embrittlement of the pipe, shortening its service life. This is primarily due to the high temperatures experienced during processing, which can cause chain breakage and oxidative degradation in the recycled HDPE molecules. High temperatures also accelerate the decomposition of residual catalysts, additives, and other substances in the material, exacerbating the aging process. This problem is currently addressed by adding commercially available antioxidants, but these are prone to migration and precipitation, making it difficult to achieve sustained and stable antioxidant performance. Summary of the Invention

[0005] The present invention provides a special material for the outer wall of a PE double-wall corrugated pipe and a preparation method thereof, which can solve the problem of poor durable antioxidant performance of the outer wall material of the double-wall corrugated pipe using recycled polyethylene material and commercially available antioxidants in the prior art.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A special material for the outer wall of a PE double-wall corrugated pipe, comprising the following raw materials in parts by weight: 100-125 parts of modified recycled polyethylene; 10-15 parts of sepiolite loaded with rare earth ions; 15-20 parts of talcum powder; 10-20 parts of calcium carbonate; 1-3 parts of nano titanium dioxide; 2-6 parts of POSS-based siloxane; 3-6 parts of lubricant.

[0007] Furthermore, the raw materials for preparing the modified recycled polyethylene include recycled polyethylene, acrylic acid, glycidyl methacrylate, and dicumyl peroxide.

[0008] Furthermore, the method for preparing modified recycled polyethylene comprises the following steps: The recycled polyethylene, acrylic acid, glycidyl methacrylate and dicumyl peroxide are mixed evenly and then transferred to a twin-screw extruder. The temperature is set at 170-220°C, the material residence time in the extruder is 3-5 minutes, the main engine speed is 5Hz, and after drawing, cooling, pelletizing, and drying at 60-80°C for 8-12 hours, the modified recycled polyethylene is obtained.

[0009] Furthermore, the mass ratio of recycled polyethylene, acrylic acid, glycidyl methacrylate and diisopropyl benzene peroxide is 100:0.6-1.0:1.2-1.5:0.12-0.14. Acrylic acid and glycidyl methacrylate are used as grafting monomers and diisopropyl benzene peroxide is used as initiator. Modified recycled polyethylene carrying epoxy and carboxyl groups is obtained through melt grafting modification.

[0010] Furthermore, the recycled polyethylene is composed of crushed polyethylene from flower ash and recycled polyethylene from blue barrels in a mass ratio of 50-100:25-50.

[0011] Furthermore, the melt mass flow rate of the Huayi crushed material (5kg, 190°C) is 1.0-2.5g / 10min.

[0012] Furthermore, the blue barrel recycled material comes from discarded HDPE blue barrels, and the melt mass flow rate (5kg, 190°C) is 0.2-0.6g / 10min.

[0013] Furthermore, the raw materials for preparing the sepiolite loaded with rare earth ions include sepiolite and rare earth salts.

[0014] Furthermore, the rare earth salt is at least one of lanthanum chloride, lanthanum nitrate, cerium chloride and cerium nitrate.

[0015] Furthermore, the method for preparing the rare earth ion-loaded sepiolite comprises the following steps: Adding sepiolite to a hydrochloric acid solution, subjecting it to ultrasonic oscillation treatment at 65-75° C. for 2-4 hours, and then filtering the filter cake, washing it with deionized water, and drying it to obtain acidified sepiolite; The acidified sepiolite is added to a rare earth salt solution and ultrasonically treated for 0.3-1h. After the ultrasonic treatment, vacuuming, filtering and drying are carried out in sequence to obtain the sepiolite loaded with rare earth ions.

[0016] Sepiolite is a natural silicate mineral with a large specific surface area. Through acidification treatment, the specific surface area and pore volume of sepiolite are increased, providing abundant adsorption sites for rare earth ions. Through impregnation treatment, sepiolite loaded with rare earth ions is obtained.

[0017] Furthermore, the concentration of the hydrochloric acid solution in the acidified sepiolite preparation process is 1 mol / L, and the sepiolite particle size is 100-320 mesh.

[0018] Furthermore, the concentration of the rare earth salt solution is 0.05-0.5 mol / L, and the mass ratio of sepiolite to rare earth salt is 100:1-5.

[0019] Furthermore, the raw materials for preparing the POSS-based siloxane include octaaminopropyl polysilsesquioxane and aldehyde-based siloxane, and the molar ratio of octaaminopropyl polysilsesquioxane to aldehyde-based siloxane is 1:1-7.

[0020] Furthermore, the aldehyde siloxane is 4-trimethoxysilylbutyraldehyde and / or triethoxysilylbutyraldehyde.

[0021] Furthermore, the method for preparing the POSS-based siloxane comprises the following steps: Octaaminopropyl polysilsesquioxane was added to anhydrous methanol, and triethylamine was added dropwise after stirring. After the addition was complete, aldehyde siloxane was added. Under closed conditions, the reaction was stirred at 25°C for 2-4 hours. After the reaction was completed, the methanol was removed by rotary evaporation to obtain POSS-based siloxane.

[0022] Furthermore, in the above preparation method, the amount of triethylamine used is the same as the molar amount of aldehyde siloxane, and octaaminopropyl polysilsesquioxane and aldehyde siloxane are used as raw materials to prepare POSS-based siloxane carrying a C=N bond through a Schiff reaction.

[0023] Furthermore, the talc powder has a particle size of 800-1250 mesh.

[0024] Furthermore, the calcium carbonate is 600-1000 mesh.

[0025] Furthermore, the lubricant is polyethylene wax.

[0026] The method for preparing the above-mentioned special material for the outer wall of the PE double-wall corrugated pipe comprises the following steps: Step 1, talcum powder, calcium carbonate, nano titanium dioxide, and POSS-based siloxane are added to a mixer and stirred for 0.5-1h, followed by adding modified recycled polyethylene, rare earth ion-loaded sepiolite, and a lubricant, and continuing stirring for 5-10min to obtain a mixture; Step 2: Add the mixed material into a twin-screw extruder for mixing and extrusion, and then cool and pelletize to obtain the special material for the outer wall of the PE double-wall corrugated pipe.

[0027] Furthermore, in step 1, the rotation speed of the mixer is 600-1000 r / min, and the temperature of the mixer is 110-120°C.

[0028] Furthermore, in step 2, the processing temperature of the twin-screw extruder is 180-210°C.

[0029] Beneficial effects of the present invention: 1. The special material for the outer wall of the PE double-wall corrugated pipe provided by the present invention uses crushed materials from Huayi and recycled materials from blue barrels as the main raw materials, which reduces the formula cost and does not require the use of new polyethylene resin materials. Through the modification process, the material properties meet the requirements for the use of double-wall corrugated pipes, the pipe performance is excellent, the ring flexibility is greatly improved, and the impact performance can basically meet the national standard requirements.

[0030] 2. The present invention uses acrylic acid and glycidyl methacrylate as grafting monomers and dicumyl peroxide as an initiator, and obtains modified recycled polyethylene carrying epoxy and carboxyl groups through melt grafting modification. The introduction of epoxy groups can improve the bonding between the polymer and the filler, so that the filler forms a uniform barrier layer in the polymer, and suppresses the speed of oxygen molecules penetrating into the material through the "maze effect", thereby enhancing the anti-aging performance of the composite material. The carboxyl groups provide active sites for complexing with rare earth ions.

[0031] 3. The present invention utilizes sepiolite loaded with rare earth ions as a filler. By loading the rare earth ions, the specific surface area of ​​the sepiolite is increased, which is beneficial to improving the binding property between the sepiolite and the modified polyethylene. The sepiolite loaded with rare earth ions can also undergo a complex reaction (carboxyl groups and rare earth ions) with the modified polyethylene to form a cross-linked network in the composite material, significantly enhancing the intermolecular forces, thereby effectively improving the tensile properties of the composite material. In addition, the rare earth ions can react with oxygen-containing free radicals generated during the aging process of the composite material to terminate the chain reaction, thereby slowing the aging process and improving the anti-aging properties of the composite material. The use of commercially available antioxidants is omitted, and the composite material is endowed with long-lasting and effective antioxidant properties.

[0032] 4. the present invention takes POSS-based siloxane as a surface treatment agent. In the preparation process of the special material for the outer wall of PE double-wall corrugated pipe, POSS-based siloxane is first subjected to a blended graft reaction with talcum powder and calcium carbonate. A POSS modifying layer carrying amino and C=N is introduced on the surfaces of talcum powder and calcium carbonate. On the one hand, the dispersibility of talcum powder and calcium carbonate in the polymer system is improved. On the other hand, the energy brought by external force is dispersed and absorbed by POSS with a cage structure and Si-O-Si flexible chain, thereby hindering the derivation of cracks, thereby improving the toughness of the material. In addition, the introduced C=N group (as a coordination site) acts together with the carboxyl group in the modified recycled polyethylene, and can form a multi-stage cross-linked network with the sepiolite loaded with rare earth ions through a metal-coordinate bond. When the composite material is subjected to an external force, the metal coordination bond is a weak base, which can be broken before the covalent bond, thereby consuming a large amount of energy, thereby significantly improving the tensile strength and toughness of the composite material. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0034] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass described in the examples of this application may be a mass unit known in the chemical industry, such as μg, mg, g, kg, etc.

[0035] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0036] The technical solution of the present application is illustrated below through specific embodiments and comparative examples.

[0037] Preparation Example 1

[0038] This preparation example provides a modified recycled polyethylene, and the preparation method is as follows: 100 g of recycled polyethylene, 0.6 g of acrylic acid, 1.2 g of glycidyl methacrylate and 0.12 g of dicumyl peroxide were mixed evenly and transferred to a twin-screw extruder. The temperature was set at 170 ° C, the material residence time in the extruder was 3 min, the main engine speed was 5 Hz, and after drawing, cooling, pelletizing, and drying at 60 ° C for 8 h, modified recycled polyethylene was obtained.

[0039] The recycled polyethylene is composed of crushed HDPE from discarded HDPE blue drums in a 50:50 mass ratio. The melt flow rate of the crushed HDPE from discarded HDPE blue drums is 2.5 g / 10 min (5 kg, 190°C). The recycled HDPE from discarded HDPE blue drums has a melt flow rate of 0.6 g / 10 min (5 kg, 190°C).

[0040] Preparation Example 2

[0041] This preparation example provides a modified recycled polyethylene, and the preparation method is as follows: 100 g of recycled polyethylene, 1.0 g of acrylic acid, 1.5 g of glycidyl methacrylate and 0.14 g of dicumyl peroxide were mixed evenly and transferred to a twin-screw extruder. The temperature was set at 220°C, the material residence time in the extruder was 5 min, the main engine speed was 5 Hz, and after drawing, cooling, pelletizing, and drying at 80°C for 12 h, modified recycled polyethylene was obtained.

[0042] The recycled polyethylene is composed of crushed HDPE from discarded HDPE blue drums and recycled HDPE from blue drums in a mass ratio of 100:25. The melt flow rate of the crushed HDPE from discarded HDPE blue drums (5 kg, 190°C) is 2.5 g / 10 min. The recycled HDPE from discarded HDPE blue drums has a melt flow rate of 0.6 g / 10 min (5 kg, 190°C).

[0043] Comparative Example 1

[0044] This preparation example provides a modified recycled polyethylene. Compared with Preparation Example 1, the only difference is that the acrylic acid in Preparation Example 1 is replaced by an equal mass of glycidyl methacrylate.

[0045] Comparative Example 2

[0046] This preparation example provides a modified recycled polyethylene. Compared with Preparation Example 1, the only difference is that the glycidyl methacrylate in Preparation Example 1 is replaced by acrylic acid of equal mass.

[0047] Example 1

[0048] A special material for the outer wall of a PE double-wall corrugated pipe, comprising the following raw materials in parts by weight: 100 parts of the modified recycled polyethylene of Preparation Example 1; 10 parts of sepiolite loaded with rare earth ions; 15 parts of talcum powder; 10 parts of calcium carbonate; 1 part of nano titanium dioxide; 2 parts of POSS-based siloxane; 3 parts of polyethylene wax.

[0049] The method for preparing sepiolite loaded with rare earth ions comprises the following steps: 10 g of sepiolite (particle size 100-320 mesh) was added to 100 mL of 1 mol / L hydrochloric acid solution, and ultrasonically vibrated at 65°C for 2 h. The mixture was then filtered, and the filter cake was washed with deionized water and dried to obtain acidified sepiolite. 10 g of acidified sepiolite was added to a 0.05 mol / Lanthanum chloride solution and ultrasonically treated for 0.3 h. The mass ratio of sepiolite to lanthanum chloride was controlled to be 10:0.1. After the ultrasonic treatment, vacuuming, filtration and drying were carried out in sequence to obtain sepiolite loaded with rare earth ions.

[0050] The method for preparing POSS-based siloxane comprises the following steps: 0.1 mol of octaaminopropyl polysilsesquioxane (Xi'an Qiyue Biotechnology Co., Ltd.) was added to anhydrous methanol, stirred evenly, and then 0.1 mol of triethylamine was added dropwise. After the addition was complete, 0.1 mol of 4-trimethoxysilylbutyraldehyde was added. Under closed conditions, the mixture was stirred at 25°C for 2 h. After the reaction was completed, the methanol was removed by rotary evaporation to obtain POSS-based siloxane.

[0051] The particle size of talc is 800-1250 mesh, and that of calcium carbonate is 600-1000 mesh.

[0052] The method for preparing the above-mentioned special material for the outer wall of the PE double-wall corrugated pipe comprises the following steps: Step 1, talcum powder, calcium carbonate, nano titanium dioxide, and POSS-based siloxane are added to a mixer at a temperature of 110° C. and a speed of 600 r / min, and stirred for 0.5 h. Then, modified recycled polyethylene, rare earth ion-loaded sepiolite, and lubricant are added, and stirring is continued for 5 min to obtain a mixture; Step 2. Add the mixed material into a twin-screw extruder for mixing and extrusion, and then cool and pelletize to obtain a special material for the outer wall of a PE double-wall corrugated pipe. The aspect ratio of the twin screws in the twin-screw extruder is 40:1, the main engine speed is 350r / min, and the temperature is set to: 180℃ in zone 1, 190℃ in zone 2, 200℃ in zone 3, 210℃ in zone 4, 200℃ in zone 5, 195℃ in zone 6, 190℃ in zone 7, 185℃ in zone 8, 175℃ in zone 9, 165℃ in zone 10, 160℃ in die head, and 160℃ in filter grinding head.

[0053] Example 2

[0054] A special material for the outer wall of a PE double-wall corrugated pipe, comprising the following raw materials in parts by weight: 115 parts of the modified recycled polyethylene of Preparation Example 1; 12 parts of sepiolite loaded with rare earth ions; 18 parts of talcum powder; 15 parts of calcium carbonate; 2 parts of nano titanium dioxide; 4 parts of POSS-based siloxane; 5 parts of polyethylene wax.

[0055] The preparation method of sepiolite loaded with rare earth ions is the same as that in Example 1.

[0056] The preparation method of POSS-based siloxane is the same as that in Example 1.

[0057] The method for preparing the above-mentioned special material for the outer wall of the PE double-wall corrugated pipe comprises the following steps: Step 1, talcum powder, calcium carbonate, nano titanium dioxide, and POSS-based siloxane are added to a mixer at a temperature of 115° C. and a speed of 800 r / min, and stirred for 0.8 h. Then, modified recycled polyethylene, rare earth ion-loaded sepiolite, and lubricant are added, and stirring is continued for 8 min to obtain a mixture; Step 2. Add the mixed material into a twin-screw extruder for mixing and extrusion, and then cool and pelletize to obtain a special material for the outer wall of a PE double-wall corrugated pipe. The aspect ratio of the twin screws in the twin-screw extruder is 40:1, the main engine speed is 350r / min, and the temperature is set to: 180℃ in zone 1, 190℃ in zone 2, 200℃ in zone 3, 210℃ in zone 4, 200℃ in zone 5, 195℃ in zone 6, 190℃ in zone 7, 185℃ in zone 8, 175℃ in zone 9, 165℃ in zone 10, 160℃ in die head, and 160℃ in filter grinding head.

[0058] Example 3

[0059] A special material for the outer wall of a PE double-wall corrugated pipe, comprising the following raw materials in parts by weight: 125 parts of the modified recycled polyethylene of Preparation Example 1; 15 parts of sepiolite loaded with rare earth ions; 20 parts of talcum powder; 20 parts of calcium carbonate; 3 parts of nano titanium dioxide; 6 parts of POSS-based siloxane; 6 parts of polyethylene wax.

[0060] The preparation method of sepiolite loaded with rare earth ions is the same as that in Example 1.

[0061] The preparation method of POSS-based siloxane is the same as that in Example 1.

[0062] The particle size of talc is 800-1250 mesh, and that of calcium carbonate is 600-1000 mesh.

[0063] The special material for the outer wall of the above-mentioned PE double-wall corrugated pipe is the same as that in Example 1.

[0064] Example 4

[0065] A special material for the outer wall of a PE double-wall corrugated pipe. Compared with Example 1, the only difference is that the modified recycled polyethylene in Example 1 is replaced by the product obtained in Preparation Example 2.

[0066] Example 5

[0067] A special material for the outer wall of a PE double-wall corrugated pipe, which differs from Example 1 only in that the sepiolite loaded with rare earth ions in this example is prepared as follows: 10 g of sepiolite (particle size 100-320 mesh) was added to 100 mL of 1 mol / L hydrochloric acid solution, and ultrasonically vibrated at 75°C for 4 h. The mixture was then filtered, and the filter cake was washed with deionized water and dried to obtain acidified sepiolite. 10 g of acidified sepiolite was added to 0.25 mol / L lanthanum nitrate and ultrasonicated for 0.5 h. The mass ratio of sepiolite to lanthanum nitrate was controlled to be 10:0.25. After the ultrasonication, vacuumization, filtration and drying were carried out in sequence to obtain sepiolite loaded with rare earth ions.

[0068] Example 6

[0069] A special material for the outer wall of a PE double-wall corrugated pipe, which differs from Example 1 only in that the sepiolite loaded with rare earth ions in this example is prepared as follows: 10 g of sepiolite (particle size 100-320 mesh) was added to 100 mL of 1 mol / L hydrochloric acid solution, and ultrasonically vibrated at 75°C for 4 h. The mixture was then filtered, and the filter cake was washed with deionized water and dried to obtain acidified sepiolite. 10 g of acidified sepiolite was added to a 0.5 mol / L cerium chloride solution and ultrasonically treated for 1 h. The mass ratio of sepiolite to cerium chloride was controlled to be 10:0.5. After the ultrasonic treatment, vacuuming, filtration and drying were carried out in sequence to obtain sepiolite loaded with rare earth ions.

[0070] Example 7

[0071] A special material for the outer wall of a PE double-wall corrugated pipe is provided, which is different from Example 1 only in that the preparation method of the POSS-based siloxane in this embodiment is as follows: 0.1 mol of octaaminopropyl polysilsesquioxane (Xi'an Qiyue Biotechnology Co., Ltd.) was added to 1 L of anhydrous methanol, stirred evenly, and then 0.35 mol of triethylamine was added dropwise. After the addition was complete, 0.35 mol of 4-trimethoxysilylbutyraldehyde was added. Under closed conditions, the mixture was stirred at 25°C for 2-4 h. After the reaction was completed, the methanol was removed by rotary evaporation to obtain POSS-based siloxane.

[0072] Example 8

[0073] A special material for the outer wall of a PE double-wall corrugated pipe is provided, which is different from Example 1 only in that the preparation method of the POSS-based siloxane in this embodiment is as follows: The method for preparing POSS-based siloxane comprises the following steps: 0.1 mol of octaaminopropyl polysilsesquioxane (Xi'an Qiyue Biotechnology Co., Ltd.) was added to 1 L of anhydrous methanol, stirred evenly, and then 0.7 mol of triethylamine was added dropwise. After the addition was complete, 0.7 mol of triethoxysilylbutyraldehyde was added. Under closed conditions, the reaction was stirred at 25°C for 4 h. After the reaction was completed, the methanol was removed by rotary evaporation to obtain POSS-based siloxane.

[0074] Comparative Example 1

[0075] A special material for the outer wall of a PE double-wall corrugated pipe, which differs from Example 1 only in that the modified recycled polyethylene in Example 1 is replaced by the product obtained in Control Example 1.

[0076] Comparative Example 2

[0077] A special material for the outer wall of a PE double-wall corrugated pipe, which differs from Example 1 only in that the modified recycled polyethylene in Example 1 is replaced by the product obtained in Control Example 2.

[0078] Comparative Example 3

[0079] A special material for the outer wall of a PE double-wall corrugated pipe is provided. Compared with Example 1, the only difference is that the sepiolite loaded with rare earth ions in Example 1 is replaced by sepiolite of equal mass (with a particle size of 100-320 mesh).

[0080] Comparative Example 4

[0081] A special material for the outer wall of a PE double-wall corrugated pipe is disclosed. Compared with Example 1, the only difference is that the POSS-based siloxane in Example 1 is replaced by a silane coupling agent KH-550 of equal mass.

[0082] Performance tests were performed on Examples 1 to 8 and Comparative Examples 1 to 4, and the test items were as follows: Oxidation induction time (OIT) was tested according to GB / T 19466.6-2009 using an aluminum cup; flexural modulus and flexural strength were tested according to GB / T 9341-2008. Elongation at break was measured according to GB / T 1040.2-2006, with a tensile speed of 50 mm / min; The notched impact strength of simply supported beam is tested according to GB / T 1043.1-2008, type A notch, 23°C; The results are shown in Table 1: Table 1

[0083] From the data recorded in Table 1, it can be seen that the PE double-wall corrugated pipe outer wall special material prepared in Examples 1 to 8 of the present invention has a bending modulus of ≥1900 MPa, an elongation at break ≥600%, and a notched impact strength ≥35 kJ / m 2 , oxidation induction time (200 ° C) ≥ 48.3 min, it can be seen that the material obtained in the above embodiment has excellent performance, high elongation at break, notched impact strength and flexural modulus, and meets the high rigidity and high toughness requirements of double-wall corrugated pipes; Specifically, from the test results of Example 1 and Comparative Examples 1 and 2 in Table 1, it can be seen that the mechanical properties of the special material obtained by synergistic modification of recycled polyethylene by acrylic acid and glycidyl methacrylate in Preparation Example 1 are significantly better than those using a single modifier; From the test results of Example 1 and Comparative Example 3, it can be seen that after the sepiolite is acidified and pore-expanded and loaded with rare earth ions, the rare earth ions can capture free radicals, improve the thermal stability of the material, and form a coordination effect with the modified recycled polyethylene, significantly improving the antioxidant and impact resistance of the composite material. It can be seen from the test results of Example 1 and Comparative Example 4 that octaaminopropyl POSS reacts with aldehyde silane to generate a POSS derivative containing a flexible siloxane chain, which has both nano-reinforcement and interface compatibilization effects, and is beneficial to improving the mechanical properties and antioxidant properties of the composite material.

[0084] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0085] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A special material for the outer wall of a PE double-wall corrugated pipe, characterized in that: It includes the following raw materials in parts by weight: 100-125 parts of modified recycled polyethylene; 10-15 parts of sepiolite loaded with rare earth ions; 15-20 parts of talcum powder; 10-20 parts of calcium carbonate; 1-3 parts of nano titanium dioxide; 2-6 parts of POSS-based siloxane; 3-6 parts of lubricant.

2. A PE double-wall corrugated pipe outer wall special material according to claim 1, characterized in that: The modified recycled polyethylene preparation method comprises the following steps: The recycled polyethylene, acrylic acid, glycidyl methacrylate and dicumyl peroxide are mixed evenly and then transferred to a twin-screw extruder. The temperature is set at 170-220°C, the material residence time in the extruder is 3-5 minutes, the main engine speed is 5Hz, and after drawing, cooling, pelletizing, and drying at 60-80°C for 8-12 hours, the modified recycled polyethylene is obtained.

3. A special material for outer wall of PE double-wall corrugated pipe according to claim 2, characterized in that: The mass ratio of recovered polyethylene, acrylic acid, glycidyl methacrylate and dicumyl peroxide is 100:0.6-1.0:1.2-1.5:0.12-0.

14.

4. A special material for outer wall of PE double-wall corrugated pipe according to claim 3, characterized in that: The recycled polyethylene is composed of crushed polyethylene from flower barrels and recycled polyethylene from blue barrels in a mass ratio of 50-100:25-50.

5. The special material for outer wall of PE double-wall corrugated pipe according to claim 1, characterized in that: The raw materials for preparing the rare earth ion-loaded sepiolite include sepiolite and rare earth salt.

6. A special material for outer wall of PE double-wall corrugated pipe according to claim 5, characterized in that: The rare earth salt is at least one of lanthanum chloride, lanthanum nitrate, cerium chloride and cerium nitrate.

7. The special material for outer wall of PE double-wall corrugated pipe according to claim 1, characterized in that: The raw materials for preparing the POSS-based siloxane include octaaminopropyl polysilsesquioxane and aldehyde-based siloxane, and the molar ratio of the octaaminopropyl polysilsesquioxane to the aldehyde-based siloxane is 1:1-7.

8. The special material for outer wall of PE double-wall corrugated pipe according to claim 7, characterized in that: The aldehyde siloxane is 4-trimethoxysilyl butyraldehyde and / or triethoxysilyl butyraldehyde.

9. The special material for outer wall of PE double-wall corrugated pipe according to claim 1, characterized in that: Described POSS group siloxane preparation method comprises the following steps: Octaaminopropyl polysilsesquioxane was added to anhydrous methanol, and triethylamine was added dropwise after stirring. After the addition was complete, aldehyde siloxane was added. Under closed conditions, the reaction was stirred at 25°C for 2-4 hours. After the reaction was completed, the methanol was removed by rotary evaporation to obtain POSS-based siloxane.

10. A method for preparing a special material for the outer wall of a PE double-wall corrugated pipe, characterized in that: The method for preparing the special material for the outer wall of the PE double-wall corrugated pipe according to any one of claims 1 to 9 comprises the following steps: Step 1, talcum powder, calcium carbonate, nano titanium dioxide, and POSS-based siloxane are added to a mixer and stirred for 0.5-1h, followed by adding modified recycled polyethylene, rare earth ion-loaded sepiolite, and a lubricant, and continuing stirring for 5-10min to obtain a mixture; Step 2: Add the mixed material into a twin-screw extruder for mixing and extrusion, and then cool and pelletize to obtain the special material for the outer wall of the PE double-wall corrugated pipe.

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