Non-excavation pipeline local repair material and preparation method thereof

Abstract

The invention belongs to the technical field of repair materials, and particularly discloses a non-excavation pipeline local repair material and a preparation method thereof. The non-excavation pipeline local repair material is prepared from the following raw materials in parts by weight: 120 to 130 parts of PVC (Polyvinyl Chloride) resin, 30 to 35 parts of modified ramie fiber, 10 to 15 parts of gypsum, 28 to 32 parts of modified zeolite powder, 7 to 9 parts of white oil, 6 to 8 parts of calcium-zinc stabilizer and 4 to 6 parts of silane coupling agent. The non-excavation pipeline local repair material prepared in the invention has excellent mechanical properties, wear resistance and corrosion resistance, the aging resistance of the repair material is improved, and the service life of the repaired pipeline is prolonged.

Description

Technical Field

[0001] This application relates to the technical field of repair materials, and particularly to a trenchless pipeline local repair material and a preparation method thereof. Background Art

[0002] Trenchless pipeline local repair is a technology for repairing pipelines without excavating the ground. This repair method has the advantages of fast construction speed, low cost, and little impact on the surrounding environment, so it has been widely used in urban pipeline repair. Common trenchless pipeline local repair methods include local resin repair process, hot inversion repair, ultraviolet light UV CIPP curing repair, etc.

[0003] Among them, the thermoplastic forming trenchless repair process utilizes the plasticity of thermoplastic materials (such as PE, PVC, etc.) after heating. Through specific equipment and processes, the materials are closely attached to the inner or outer wall of the pipeline to be repaired, forming a new pipeline lining or outer wall with excellent performance. During the heating process, the thermoplastic material softens and flows, filling the defects in the pipeline, such as cracks, corrosion pits, etc., and then solidifies during the cooling process, forming a strong and sealed new pipeline layer, which has the advantages of strong adaptability, fast and efficient, no need for excavation, and convenient operation.

[0004] The main component of the existing thermoplastic forming materials is polyvinyl chloride (PVC). At lower temperatures, it transforms into a glassy state, and at higher temperatures, it transforms into a high elastic state, having a certain flexibility and being able to bend smoothly at the corners of long-distance pipeline repairs. However, polyvinyl chloride has poor aging resistance. When used outdoors, it is prone to aging, and its strength and toughness will also decrease accordingly, affecting the service life. Summary of the Invention

[0005] In order to improve the aging resistance of polyvinyl chloride, this application provides a trenchless pipeline local repair material and a preparation method thereof.

[0006] This application provides a trenchless pipeline local repair material, adopting the following technical scheme: A trenchless pipeline local repair material, in parts by weight, comprises the following raw materials: 120 - 130 parts of PVC resin, 30 - 35 parts of modified ramie fiber, 10 - 15 parts of gypsum, 28 - 32 parts of modified zeolite powder, 7 - 9 parts of white oil, 6 - 8 parts of calcium-zinc stabilizer, and 4 - 6 parts of silane coupling agent.

[0007] By adopting the above technical solutions, PVC resin, as the main base material, has good physical and chemical properties, such as corrosion resistance, wear resistance, and insulation, providing the basic strength and durability of the repair layer. The modified ramie fiber has high strength and wear resistance, is dispersed in the system structure, improves the overall strength and toughness of the repair layer, and enhances the structural strength of the pipeline after repair. Gypsum has good filling and solidification properties, can fill the gaps at the local damaged parts of the trenchless pipeline, and improve the density and sealing performance of the repair layer. The modified zeolite powder has a porous structure. As an admixture, when combined with the modified ramie fiber, the modified ramie fiber can be loaded on the particle surface and pores of the modified zeolite powder, improving the compressive strength and durability of the repair layer; when mixed with gypsum, it can improve the microstructure of the repair layer and enhance the overall performance and durability of the repair layer.

[0008] White oil has good lubricity and rust prevention properties. During the local repair process of the trenchless pipeline, as an anti-rust agent or lubricant, it reduces the friction between the repair material and the inner wall of the pipeline, protecting the pipeline from further corrosion. The calcium-zinc stabilizer improves the thermal stability and processing performance of the mixed system. In the trenchless pipeline repair material, it improves the stability of the repair layer under high temperature or harsh environments, preventing the aging or deterioration of the repair layer. The silane coupling agent improves the interfacial bonding performance between inorganic materials and organic materials. As an interfacial enhancer, the silane coupling agent improves the adhesion between the repair layer and the inner wall of the pipeline, ensuring the firmness and durability of the repair layer.

[0009] The prepared thermoplastic non-excavation repair material is melted by heating during use for patching and solidifies after cooling. The repaired pipeline obtained has excellent comprehensive performance. These materials play important roles respectively in the local repair of trenchless pipelines. They jointly constitute a high-performance repair material, providing reliable technical support for pipeline repair.

[0010] Preferably, the preparation method of the modified ramie fiber includes the following steps: (1) Disperse the ramie fiber in deionized water, stir at a temperature of 60 - 65 °C for 1 - 2 h, add N-methylpyrrolidone, continue stirring for 2 - 3 h, filter, and dry to obtain pretreated ramie fiber; (2) Disperse the modified nano-silica in deionized water, add the pretreated ramie fiber obtained in step (1), stir at a temperature of 75 - 80 °C for 1 - 2 h, add sodium dodecylbenzenesulfonate and carboxymethyl cellulose, stir evenly, and dry to obtain the modified ramie fiber.

[0011] By adopting the above technical solution, ramie fibers are dispersed in deionized water, and heated to fully disperse and soften the ramie fibers in water. Then N-methylpyrrolidone is added. N-methylpyrrolidone has extremely strong dissolving ability and is used to dissolve and disperse ramie fibers, further improving the dispersibility and subsequent reactivity of ramie fibers.

[0012] The modified nano-silica has good mechanical properties, wear resistance and anti-aging properties. It can be loaded on the surface and pores of the pretreated ramie fibers to improve the mechanical properties, wear resistance and anti-aging properties of ramie fibers. Sodium hexadecyl benzene sulfonate helps to improve the dispersibility and wettability of ramie fibers and modified nano-silica, making the ramie fibers and modified nano-silica mix evenly, and enabling the modified nano-silica to be evenly loaded within the ramie fiber structure. Carboxymethyl cellulose has certain viscosity and film-forming properties, making the modified nano-silica stably adhere to the surface of ramie fibers, further increasing the strength, wear resistance, corrosion resistance and stability of the modified ramie fibers. Subsequently, it is applied to the local repair material for trenchless pipelines, improving the strength, adhesiveness and wear resistance of the repair layer and extending the durability of the repair material.

[0013] Preferably, the mass ratio of the ramie fibers, modified nano-silica and carboxymethyl cellulose is 1:0.5 - 0.6:0.1 - 0.2.

[0014] By adopting the above technical solution, further limiting the mass ratio of ramie fibers, modified nano-silica and carboxymethyl cellulose within a certain range improves the mechanical properties, wear resistance and toughness of ramie fibers. Ramie fibers have good tensile strength, toughness and wear resistance, enabling the repaired pipeline to have better pressure-bearing and water-stopping capabilities. The modified nano-silica has extremely small particle size and high specific surface area. The modified nano-silica can be loaded on the surface of ramie fibers, improving the hardness, wear resistance, thermal stability and chemical stability of the repair material, enabling it to still maintain good performance under harsh environments. Carboxymethyl cellulose has good viscosity, making the modified nano-silica and ramie fibers better combined together to form a uniform and dense repair layer.

[0015] The stripe grooves on the surface of ramie fibers can increase the contact area with matrix materials such as resin, enabling the resin to completely spread on the surface of ramie fibers, showing strong interfacial adhesion performance, thus enhancing the bonding force between the repair material and the inner wall of the pipeline. The modified nano-silica can serve as a "bridge" for resin infiltration, promoting the infiltration and curing of resin between ramie fibers, thereby improving the overall performance of the repair material. Carboxymethyl cellulose can form a protective film covering the surface of the repair material, improving the water resistance and corrosion resistance of the material. The ramie fibers, modified nano-silica and carboxymethyl cellulose are mixed to jointly improve the strength, adhesiveness, corrosion resistance and wear resistance of the repair material and extend the durability of the repair material.

[0016] Preferably, the preparation method of the modified nano-silica includes the following steps: dispersing nano-silica in a toluene solution of KH-550, ultrasonicating for 40-45 min, filtering, drying to obtain pretreated nano-silica, then dispersing it in deionized water, adding sodium dodecylbenzenesulfonate, fly ash, and sodium alginate, stirring for 3-5 h, drying, and grinding to obtain modified nano-silica.

[0017] By adopting the above technical solution, dispersing nano-silica in a toluene solution of KH-550 enables better dispersion of nano-silica in the toluene solution, removing some aggregates to obtain pretreated nano-silica. Then, it is dispersed in deionized water, and sodium dodecylbenzenesulfonate, fly ash, and sodium alginate are added. Sodium dodecylbenzenesulfonate helps improve the dispersion and stability of fly ash and nano-silica in water. Fly ash has a certain particle size and strength, and nano-silica can be loaded in the pores of fly ash to improve the strength of the system. Sodium alginate has good thickening and stabilizing properties, increasing the viscosity and stability of the repair material, making nano-silica and fly ash adhere tightly, improving the comprehensive performance of the system. The obtained modified nano-silica has good strength, density, weather resistance, fluidity, and adhesiveness, and is subsequently applied to trenchless pipeline local repair materials to improve the strength, wear resistance, and adhesiveness of the repair layer.

[0018] Preferably, the mass ratio of the nano-silica, fly ash, and sodium alginate is 1:0.3-0.4:0.07-0.09.

[0019] By adopting the above technical solution, further limiting the mass ratio of nano-silica, fly ash, and sodium alginate within a certain range, the obtained modified nano-silica has good comprehensive performance. Nano-silica has good strength and wear resistance and can fill the tiny pores in the pipeline repair material to improve the density and strength of the material. Fly ash has a certain particle size and strength, and nano-silica is loaded in the fly ash structure to improve the weather resistance of fly ash and extend its service life. Sodium alginate has good adhesive properties, making nano-silica and fly ash adhere tightly, increasing the adhesive strength between the repair material and the pipeline wall, improving the anti-aging performance of the repair material, and extending the durability of the repair layer.

[0020] Preferably, the preparation method of the modified zeolite powder includes the following steps: (1) Dispersing zeolite powder in a hydrochloric acid solution and stirring for 1-2 h, washing with water, then dispersing it in a sodium chloride solution and stirring for 3-4 h, washing with water, drying, and sieving to obtain pretreated zeolite powder; (2) Disperse the modified graphene in absolute ethanol, add the pretreated zeolite powder from step (1), ultrasonicate for 1 - 2 h, then add dipropylene glycol butyl ether, stir at a temperature of 60 - 65 °C for 1 - 2 h, and dry to obtain the modified zeolite powder.

[0021] By adopting the above technical solution, the zeolite powder is dispersed in the hydrochloric acid solution, enabling the zeolite powder to fully react with the hydrochloric acid, changing the properties and structure of the surface of the zeolite powder, removing the surface impurities of the zeolite powder, and improving its adsorption performance. Then it is dispersed in the sodium chloride solution and stirred, involving the ion exchange of the zeolite powder, further changing the surface charge and adsorption performance of the zeolite powder. The modified zeolite powder has a higher specific surface area and pore volume, which is beneficial for adsorbing more target substances.

[0022] The modified graphene has good mechanical properties. When mixed with the pretreated zeolite powder, the modified graphene is loaded on the surface and within the pores of the zeolite powder particles, improving the mechanical properties of the zeolite powder. Dipropylene glycol butyl ether has a certain viscosity, enabling the modified graphene to adhere to the surface of the zeolite powder, improving the mechanical properties of the modified zeolite powder. Subsequently, when applied to the non - excavation pipeline local repair material, it adheres tightly to the resin, improving the mechanical properties and adhesion of the repair layer, and extending the durability of the repair layer.

[0023] Preferably, the mass ratio of the zeolite powder, modified graphene, and dipropylene glycol butyl ether is 1 g: 60 - 70 mg: 0.2 - 0.3 g.

[0024] By adopting the above technical solution, further limiting the mass ratio of the zeolite powder, modified graphene, and dipropylene glycol butyl ether within a certain range can improve the mechanical properties and adhesion of the zeolite powder. The zeolite powder has a porous structure, which can provide a large specific surface area and adsorption capacity. The modified graphene has good mechanical strength and elastic modulus, and can be loaded on the surface and within the pores of the zeolite powder, improving the mechanical properties of the system, such as hardness, strength, and toughness. Dipropylene glycol butyl ether has good dispersibility, stability, and adhesion, enabling the modified graphene to stably adhere to the surface of the zeolite powder, increasing the strength of the modified zeolite powder. Moreover, propylene glycol butyl ether can also improve the dispersibility of graphene and zeolite powder in the mixed solution, and can form a stable complex with graphene and zeolite powder, preventing them from separating due to aggregation or precipitation.

[0025] After the zeolite powder, graphene, and dipropylene glycol butyl ether are mixed, they can produce a synergistic effect. The porous structure and ion - exchange performance of the zeolite powder can be combined with the mechanical properties of graphene, while the solvent action and dispersibility of dipropylene glycol butyl ether can help them better combine together. Subsequently, when applied to the non - excavation pipeline local repair material, it increases the mechanical strength, stability, and adhesion of the system, thereby extending the durability of the repair material.

[0026] Preferably, the preparation method of the modified graphene comprises the following steps: dispersing graphene in sulfuric acid, stirring for 35 - 40 min, washing with ethanol, then dispersing in ethanol, stirring for 25 - 30 min, adding nano-nickel, ultrasonicating for 1 - 2 h, filtering, drying to obtain pretreated graphene, then spraying an arabic gum solution, drying, and grinding to obtain modified graphene.

[0027] By adopting the above technical solution, dispersing graphene in sulfuric acid helps to break the van der Waals forces between graphene layers, thus promoting the dispersion of graphene. Washing with ethanol neutralizes the residual sulfuric acid and also helps to remove impurities on the surface of graphene. Nano-nickel has good wear resistance and strength, and ultrasonicating makes nano-nickel evenly distributed and attached to the surface of graphene, increasing the mechanical strength and wear resistance of graphene. Finally, spraying an arabic gum solution, the arabic gum solution has excellent film-forming properties and adhesiveness, which helps to form a uniform coating on the surface of graphene, can coat nano-nickel and graphene, enables nano-nickel to be stably loaded on the surface of graphene, increases the mechanical properties, corrosion resistance and wear resistance of graphene. The bonding effect of the arabic gum solution helps to ensure the integrity and stability of the repair material. Subsequently, it is applied to the local repair material of trenchless pipelines, increasing the mechanical properties, corrosion resistance and wear resistance of the repair material, and prolonging the durability of the repair material.

[0028] Preferably, the mass ratio of the graphene, nano-nickel and arabic gum solution is 0.2 - 0.3:1:0.06 - 0.08.

[0029] By adopting the above technical solution, further defining the mass ratio among graphene, nano-nickel and arabic gum solution, the obtained modified graphene has better mechanical properties and wear resistance. Graphene has extremely high mechanical strength, good fracture strength, tensile strength and compressive ability. Nano-nickel has good corrosion resistance and can maintain the stability of the material in harsh environments. Nano-nickel can be loaded on the surface of graphene, improving the mechanical properties and corrosion resistance of graphene. The arabic gum solution has good bonding properties and can firmly bond graphene and nano-nickel particles together to form a tight structure. Mixing graphene, nano-nickel and arabic gum solution together forms a pipeline repair material with excellent properties, which not only has characteristics such as high strength, high conductivity and high corrosion resistance, but also can adapt to various complex pipeline environments to ensure the safe operation of the pipeline. The arabic gum solution can also form a uniform thin film on the pipeline surface, which can prevent external substances from eroding the pipeline, and at the same time protect the repair material from damage, making the repaired pipeline more durable.

[0030] In a second aspect, the present application also provides a method for preparing a trenchless pipeline local repair material, which includes the following steps: Mix PVC resin, modified ramie fiber, gypsum, modified zeolite powder, white oil, calcium zinc stabilizer, and silane coupling agent for 1-2 hours to obtain a mixture, then extrude and mold it, and then carry out vacuum sizing, cooling, traction, annealing, and cutting to obtain the trenchless pipeline local repair material.

[0031] By adopting the above technical solution and preparation method, the process time is short and the operation is simple, which helps to improve the production efficiency of preparing the trenchless pipeline local repair material. The obtained trenchless pipeline local repair material has good mechanical properties, wear resistance, corrosion resistance, and sealing performance.

[0032] In summary, the present application has the following beneficial effects: 1. The thermoplastic molding trenchless repair material prepared in the present application is melted by heating during use for repair and solidifies after cooling. The repaired pipeline obtained has excellent comprehensive performance. These materials play important roles in the local repair of trenchless pipelines respectively, and they jointly constitute a high-performance repair material, providing reliable technical support for pipeline repair.

[0033] 2. The modified zeolite powder in the present application has a porous structure. As a blending material, in combination with the modified ramie fiber, the modified ramie fiber can be loaded on the particle surface and pores of the modified zeolite powder, improving the compressive strength and durability of the repair layer.

[0034] 3. The modified ramie fiber in the present application has high strength and wear resistance, is dispersed in the system structure, improves the overall strength and toughness of the repair layer, and enhances the structural strength of the pipeline after repair. Specific Embodiments

[0035] The following further elaborates on the present application with reference to embodiments.

[0036] The raw materials used in the embodiments and comparative examples can all be obtained commercially.

[0037] Preparation Example of Modified Ramie Fiber Preparation Example 1-1 The preparation method of the modified ramie fiber includes the following steps: (1) Disperse 50 kg of ramie fiber in 80 L of deionized water, stir at a temperature of 65 °C for 2 hours, add 3 kg of N-methylpyrrolidone, continue to stir for 3 hours, filter, and dry to obtain pretreated ramie fiber; (2) Disperse the modified nano-silica in 120 L of deionized water, add the pretreated ramie fiber obtained in step (1), stir at a temperature of 80 °C for 2 hours, add 4 g of sodium dodecylbenzenesulfonate and carboxymethyl cellulose, stir evenly, and dry to obtain the modified ramie fiber.

[0038] The mass ratio of ramie fiber, modified nano-silica, and carboxymethyl cellulose is 1:0.5:0.1.

[0039] The preparation method of modified nano-silica includes the following steps: Disperse 40 kg of nano-silica in 55 L of 1% KH-550 toluene solution, sonicate for 45 min, filter, dry to obtain pretreated nano-silica, then disperse it in 100 L of deionized water, add 3.5 kg of sodium dodecylbenzenesulfonate, fly ash, and sodium alginate, stir for 5 h, dry, and grind to obtain modified nano-silica.

[0040] The mass ratio of nano-silica, fly ash, and sodium alginate is 1:0.3:0.09.

[0041] Preparation Example 1-2 The difference from Preparation Example 1-1 is that in step (2), no modified nano-silica is added.

[0042] Preparation Example 1-3 The difference from Preparation Example 1-1 is that in step (2), no carboxymethyl cellulose is added.

[0043] Preparation Example 1-4 The difference from Preparation Example 1-1 is that the mass ratio of ramie fiber, modified nano-silica, and carboxymethyl cellulose is 1:0.6:0.2.

[0044] Preparation Example 1-5 The difference from Preparation Example 1-1 is that the mass ratio of ramie fiber, modified nano-silica, and carboxymethyl cellulose is 1:0.2:0.5.

[0045] Preparation Example 1-6 The difference from Preparation Example 1-1 is that in the preparation method of modified nano-silica, no fly ash is added.

[0046] Preparation Example 1-7 The difference from Preparation Example 1-1 is that in the preparation method of modified nano-silica, no sodium alginate is added.

[0047] Preparation Example 1-8 The difference from Preparation Example 1-1 is that in the preparation method of modified viscose fiber, the mass ratio of nano-silica, fly ash, and sodium alginate is 1:0.4:0.07.

[0048] Preparation Example 1-9 The difference from Preparation Example 1-1 is that in the preparation method of modified viscose fiber, the mass ratio of nano-silica, fly ash, and sodium alginate is 1:0.1:0.15.

[0049] Preparation Example of Modified Zeolite Powder Preparation Example 2-1 The preparation method of modified zeolite powder includes the following steps: (1) Disperse 38 kg of zeolite powder in 52 L of hydrochloric acid solution with a concentration of 0.05 mol / L, stir for 2 h, wash with water, then disperse in 55 L of sodium chloride solution with a concentration of 0.8 mol / L, stir for 4 h, wash with water, dry, and pass through a 100-mesh sieve to obtain pretreated zeolite powder; (2) Disperse modified graphene in 150 L of anhydrous ethanol, add the pretreated zeolite powder obtained in step (1), ultrasonicate for 2 h, then add dipropylene glycol butyl ether, stir at a temperature of 65 °C for 2 h, and dry to obtain modified zeolite powder.

[0050] The mass ratio of zeolite powder, modified graphene, and dipropylene glycol butyl ether is 1 g: 60 mg: 0.3 g.

[0051] The preparation method of modified graphene includes the following steps: Disperse 6 kg of graphene in 10 L of sulfuric acid with a mass fraction of 5%, stir for 40 min, wash with ethanol, then disperse in 60 L of ethanol, stir for 30 min, add nano-nickel, ultrasonicate for 2 h, filter, and dry to obtain pretreated graphene, then spray an arabic gum solution, dry, and grind to obtain modified graphene.

[0052] The mass ratio of graphene, nano-nickel, and arabic gum solution is 0.2: 1: 0.08.

[0053] Preparation Example 2-2 The difference from Preparation Example 2-1 is that in step (2), no modified graphene is added.

[0054] Preparation Example 2-3 The difference from Preparation Example 2-1 is that in step (2), no dipropylene glycol butyl ether is added.

[0055] Preparation Example 2-4 The difference from Preparation Example 2-1 is that the mass ratio of zeolite powder, modified graphene, and dipropylene glycol butyl ether is 1 g: 70 mg: 0.2 g.

[0056] Preparation Example 2-5 The difference from Preparation Example 2-1 is that the mass ratio of zeolite powder, modified graphene, and dipropylene glycol butyl ether is 1 g: 30 mg: 0.8 g.

[0057] Preparation Example 2-6 The difference from Preparation Example 2-1 is that in the preparation method of modified graphene, no nano-nickel is added.

[0058] Preparation Example 2-7 It is different from Preparation Example 2-1 in that in the preparation method of the modified graphene, no gum arabic solution is added.

[0059] Preparation Example 2-8 It is different from Preparation Example 2-1 in that the mass ratio of graphene, nano-nickel and gum arabic solution is 0.3:1:0.06.

[0060] Preparation Example 2-9 It is different from Preparation Example 2-1 in that the mass ratio of graphene, nano-nickel and gum arabic solution is 0.7:1:0.01. Examples

[0061] Example 1 A trenchless pipeline local repair material, by weight, includes the following raw materials: 120 kg of PVC resin, 30 kg of modified ramie fiber, 10 kg of gypsum, 28 kg of modified zeolite powder, 7 kg of white oil, 6 kg of calcium-zinc stabilizer, 4 kg of silane coupling agent; the PVC resin is purchased from Shandong Yueyang New Materials Co., Ltd., the calcium-zinc stabilizer is purchased from Wuhan Xindongyi Chemical Co., Ltd., and the silane coupling agent is KH-570.

[0062] The preparation method of the above trenchless pipeline local repair material includes the following steps: mixing the PVC resin, modified ramie fiber, gypsum, modified zeolite powder, white oil, calcium-zinc stabilizer, and silane coupling agent for 1-2 h to obtain a mixture, extruding and molding, and then through vacuum sizing, cooling, traction, annealing, and cutting to obtain the trenchless pipeline local repair material.

[0063] The modified ramie fiber is prepared by Preparation Example 1-1; the modified zeolite powder is prepared by Preparation Example 2-1.

[0064] Example 2 A trenchless pipeline local repair material, different from Example 1, by weight, includes the following raw materials: 130 kg of PVC resin, 35 kg of modified ramie fiber, 15 kg of gypsum, 32 kg of modified zeolite powder, 9 kg of white oil, 8 kg of calcium-zinc stabilizer, 6 kg of silane coupling agent.

[0065] Example 3 A trenchless pipeline local repair material, different from Example 1, in that the modified ramie fiber is prepared by Preparation Example 1-2.

[0066] Example 4 A trenchless pipeline local repair material, different from Example 1, in that the modified ramie fiber is prepared by Preparation Example 1-3.

[0067] Example 5 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified ramie fiber is prepared by Preparation Examples 1-4.

[0068] Example 6 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified ramie fiber is prepared by Preparation Examples 1-5.

[0069] Example 7 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified ramie fiber is prepared by Preparation Examples 1-6.

[0070] Example 8 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified ramie fiber is prepared by Preparation Examples 1-7.

[0071] Example 9 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified ramie fiber is prepared by Preparation Examples 1-8.

[0072] Example 10 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified ramie fiber is prepared by Preparation Examples 1-9.

[0073] Example 11 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified zeolite powder is prepared by Preparation Example 2-2.

[0074] Example 12 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified zeolite powder is prepared by Preparation Example 2-3.

[0075] Example 13 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified zeolite powder is prepared by Preparation Example 2-4.

[0076] Example 14 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified zeolite powder is prepared by Preparation Example 2-5.

[0077] Example 15 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified zeolite powder is prepared by Preparation Example 2-6.

[0078] Example 16 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified zeolite powder is prepared by Preparation Example 2-7.

[0079] Example 17 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified zeolite powder is prepared by Preparation Examples 2-8.

[0080] Example 18 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified zeolite powder is prepared by Preparation Examples 2-9.

[0081] Comparative Example Comparative Example 1 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified ramie fiber is not added.

[0082] Comparative Example 2 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified ramie fiber is replaced with an equal amount of ramie fiber.

[0083] Comparative Example 3 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified zeolite powder is not added.

[0084] Comparative Example 4 A trenchless pipeline local repair material, which is different from that in Example 1 in that the modified zeolite powder is replaced with an equal amount of zeolite powder.

[0085] Performance Detection Test The trenchless pipeline local repair materials prepared in Examples 1-18 and Comparative Examples 1-4 were subjected to performance tests. The reference standards for each performance test are listed in Table 1, and the test results are shown in Table 1.

[0086] Table 1 Test Data of Examples and Comparative Examples As can be seen from Table 1, the trenchless pipeline local repair materials prepared in Examples 1-2 of the present application have mechanical properties, wear resistance, anti-aging properties and corrosion resistance. Among them, the initial tensile strength of Example 1 is 56.9 MPa, the tensile strength after 6 months of exposure to the sun is 51.2 MPa, the bending strength is 98.9 MPa, the wear amount is 0.35 g. In the chemical corrosion resistance test, the bending strength after acid corrosion is 98.7% of the initial bending strength, and the bending strength after alkali corrosion is 99.3% of the initial bending strength. It shows that the prepared trenchless pipeline local repair material has excellent overall performance and durability. When used outdoors, it will not show aging phenomenon, maintain good strength and toughness, and extend the service life of the pipeline.

[0087] In the preparation methods of the modified ramie fibers in Examples 3-4, modified nano-silica and carboxymethyl cellulose were not added respectively. In Examples 5-6, the mass ratios of ramie fiber, modified nano-silica and carboxymethyl cellulose were changed. As can be seen from Table 1, the performance test results of the tensile strength, bending strength, wear amount and chemical corrosion resistance in Examples 3-4 were all worse than those in Examples 1-2 and Example 5. The corresponding performance test results in Example 6 were all better than those in Examples 3-4, but worse than those in Examples 1-2 and Example 5, indicating that the modified nano-silica can be loaded on the surface of ramie fiber, improving the hardness, wear resistance, thermal stability and chemical stability of the repair material. Carboxymethyl cellulose has good viscosity, making the modified nano-silica and ramie fiber better combined together to form a uniform and dense repair layer.

[0088] In the preparation methods of the modified nano-silica in Examples 7-8, fly ash and sodium alginate were not added respectively. In Examples 9-10, the mass ratios of nano-silica, fly ash and sodium alginate were changed. As can be seen from Table 1, the performance test results of the tensile strength, bending strength, wear amount and chemical corrosion resistance in Examples 7-8 were all better than those in Example 3. The corresponding performance test results in Example 10 were all better than those in Examples 7-8, but worse than those in Examples 1-2 and Example 9, indicating that the nano-silica is loaded within the fly ash structure. Sodium alginate has good bonding effect, making the nano-silica and fly ash bonded tightly, increasing the bonding strength between the repair material and the pipeline wall, improving the anti-aging performance of the repair material and prolonging the durability of the repair layer.

[0089] In the preparation methods of the modified zeolite powder in Examples 11-12, modified graphene and dipropylene glycol butyl ether were not added respectively. In Examples 13-14, the mass ratios of zeolite powder, modified graphene and dipropylene glycol butyl ether were changed. As can be seen from Table 1, the performance test results of the tensile strength, bending strength, wear amount and chemical corrosion resistance in Examples 11-12 were all worse than those in Examples 1-2 and Example 13. The corresponding performance test results in Example 14 were all better than those in Examples 11-12, but worse than those in Examples 1-2 and Example 13, indicating that zeolite powder, graphene and dipropylene glycol butyl ether produce a synergistic effect. The porous structure and ion exchange performance of zeolite powder can be combined with the conductivity and mechanical properties of graphene, while the solvent effect and dispersibility of dipropylene glycol butyl ether can help them better combined together. Subsequently, when applied to the trenchless pipeline local repair material, it can increase the mechanical strength, stability and adhesion of the system, and thus prolong the durability of the repair material.

[0090] In the preparation methods of modified graphene in Examples 15 - 16, nano - nickel and gum arabic solution were not added respectively. In Examples 17 - 18, the mass ratios of graphene, nano - nickel and gum arabic solution were changed. As can be seen from Table 1, the performance test results of tensile strength, flexural strength, wear amount and chemical corrosion resistance in Examples 15 - 16 are better than those in Example 11. The corresponding performance test results in Example 18 are better than those in Examples 15 - 16, but worse than those in Examples 1 - 2 and Example 15. This shows that when graphene, nano - nickel and gum arabic solution are mixed together to form a pipeline repair material with excellent properties, it has characteristics such as high strength and high corrosion resistance. Gum arabic solution has good bonding properties and can firmly bond graphene and nano - nickel particles together to form a tight structure, making the repaired pipeline more durable.

[0091] In Comparative Example 1 and Comparative Example 3, modified ramie fiber and modified zeolite powder were not added respectively. As can be seen from Table 1, the performance test results of tensile strength, flexural strength, wear amount and chemical corrosion resistance in Comparative Example 1 and Comparative Example 3 are significantly worse than those in Examples 1 - 2. This shows that modified ramie fiber has high strength and wear resistance. When dispersed in the system structure, it can improve the overall strength and toughness of the repair layer and enhance the structural strength of the repaired pipeline. Modified zeolite powder has a porous structure. As an admixture, when combined with modified ramie fiber, modified ramie fiber can be loaded on the particle surface and pores of modified zeolite powder, improving the compressive strength and durability of the repair layer.

[0092] In Comparative Example 2 and Comparative Example 4, modified ramie fiber was replaced with the same amount of ramie fiber and modified zeolite powder was replaced with the same amount of zeolite powder respectively. As can be seen from Table 1, compared with Example 1, the performance test results of tensile strength, flexural strength, wear amount and chemical corrosion resistance in Comparative Example 2 and Comparative Example 4 are significantly worse than those in Examples 1 - 2, but better than those in Comparative Example 1 and Comparative Example 3. This shows that the modified ramie fiber and modified zeolite powder in this application have good mechanical properties, mechanical performance, wear resistance and chemical corrosion resistance, maintaining the durability, structural strength and performance stability of the pipeline.

[0093] This specific embodiment is only an explanation of the present application and is not a limitation thereof. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A trenchless pipeline local repair material, characterized in that: The invention comprises the following raw materials in parts by weight: 120-130 parts of PVC resin, 30-35 parts of modified ramie fiber, 10-15 parts of gypsum, 28-32 parts of modified zeolite powder, 7-9 parts of white oil, 6-8 parts of calcium zinc stabilizer and 4-6 parts of silane coupling agent.

2. The trenchless pipeline local repair material according to claim 1, characterized in that: The preparation method of the modified ramie fiber comprises the following steps: (1) dispersing ramie fiber in deionized water, stirring at a temperature of 60-65° C. for 1-2 hours, adding N-methylpyrrolidone, continuing to stir for 2-3 hours, filtering, and drying to obtain pretreated ramie fiber; (2) Dispersing the modified nano-silica in deionized water, adding the pretreated ramie fiber of step (1), stirring at a temperature of 75-80° C. for 1-2 h, adding sodium hexadecylbenzene sulfonate and carboxymethyl cellulose, stirring evenly, and drying to obtain modified ramie fiber.

3. The trenchless pipeline local repair material according to claim 2, characterized in that: The mass ratio of the ramie fiber, the modified nano silicon dioxide and the carboxymethyl cellulose is 1:0.5-0.6:0.1-0.

2.

4. The trenchless pipeline local repair material according to claim 2, characterized in that: The preparation method of the modified nano silicon dioxide comprises the following steps: dispersing the nano silicon dioxide in a KH-550 toluene solution, ultrasonicating for 40-45 minutes, filtering, drying to obtain pretreated nano silicon dioxide, then dispersing in deionized water, adding sodium dodecylbenzene sulfonate, fly ash and sodium alginate, stirring for 3-5 hours, drying and grinding to obtain the modified nano silicon dioxide.

5. The trenchless pipeline local repair material according to claim 4, characterized in that: The mass ratio of the nano silicon dioxide, fly ash and sodium alginate is 1:0.3-0.4:0.07-0.

09.

6. The trenchless pipeline local repair material according to claim 1, characterized in that: The preparation method of the modified zeolite powder comprises the following steps: (1) dispersing the zeolite powder in a hydrochloric acid solution and stirring for 1-2 hours, washing with water, and then dispersing the zeolite powder in a sodium chloride solution and stirring for 3-4 hours, washing with water, drying, and sieving to obtain pretreated zeolite powder; (2) Dispersing the modified graphene in anhydrous ethanol, adding the pretreated zeolite powder of step (1), ultrasonicating for 1-2 hours, then adding dipropylene glycol butyl ether, stirring at a temperature of 60-65° C. for 1-2 hours, and drying to obtain modified zeolite powder.

7. The trenchless pipeline local repair material according to claim 6, characterized in that: The mass ratio of the zeolite powder, modified graphene and dipropylene glycol butyl ether is 1g:60-70mg:0.2-0.3g.

8. The trenchless pipeline local repair material according to claim 6, characterized in that: The preparation method of the modified graphene comprises the following steps: dispersing the graphene in sulfuric acid, stirring for 35-40 minutes, washing with ethanol, then dispersing the graphene in ethanol, stirring for 25-30 minutes, adding nano nickel, ultrasonicating for 1-2 hours, filtering, drying to obtain pretreated graphene, then spraying with gum arabic solution, drying, grinding to obtain modified graphene.

9. The trenchless pipeline local repair material according to claim 8, characterized in that: The mass ratio of the graphene, nano-nickel and gum arabic solution is 0.2-0.3:1:0.06-0.

08.

10. The method for preparing a trenchless pipeline local repair material according to claim 1, characterized in that: The method comprises the following steps: stirring PVC resin, modified ramie fiber, gypsum, modified zeolite powder, white oil, calcium zinc stabilizer and silane coupling agent for 1-2 hours to obtain a mixture, extruding the mixture, and then vacuum sizing, cooling, pulling, annealing and cutting to obtain a trenchless pipeline local repair material.

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