High-strength wear-resistant polyethylene gas pipeline and preparation method thereof

Abstract

The invention relates to a high-strength wear-resistant polyethylene gas pipeline and a preparation method thereof, and belongs to the technical field of high polymer materials. The high-density polyethylene, the modified ethylene propylene diene monomer, the modified chlorinated polyethylene rubber, the modified basalt fiber, the silicon carbide ceramic material, the magnesium oxide, the lubricant, the hindered amine light stabilizer, the hindered phenol antioxidant, the antistatic agent and the like are adopted as raw materials for compounding; and according to the material properties and dispersion characteristics of all the components, the process steps and parameters of mixing, banburying, extruding and the like are designed, so that the production of the pipeline can be well realized, and the gas pipeline with uniform quality and excellent performance is obtained. The compressive strength, the impact resistance and the wear resistance of the pipeline are greatly improved, the weather resistance of the pipeline is effectively improved, the service performance of the pipeline is comprehensively improved, the service life of the pipeline is comprehensively prolonged, and the pipeline is more suitable for being used in various severe environments, can meet the use requirements of long-distance construction, long-term friction and high-pressure environments and can be widely applied to high, medium and low-pressure gas conveying. Civil and industrial fuel gas conveying is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to a high-strength wear-resistant polyethylene gas pipeline and a preparation method thereof. Background Art

[0002] With the continuous development and progress of society, gas, as an efficient and clean energy source, is playing an increasingly important role in people's daily lives and industrial production. As a key carrier for gas transportation, the technical level of gas pipelines is directly related to the safe and stable supply of gas.

[0003] Commonly used gas pipeline materials include cast iron, steel, and polyethylene pipes. Cast iron was once a primary material for gas pipelines, but due to its heavy weight, difficulty in construction, and poor corrosion resistance, it has been gradually replaced by steel and polyethylene pipes. Steel pipe offers advantages such as high strength, wear resistance, and excellent pressure resistance, but it is also relatively heavy and has relatively poor corrosion resistance. It is susceptible to corrosion from gas (corrosive components such as hydrogen sulfide) and the environment, significantly increasing the cost of anti-corrosion measures. Consequently, polyethylene pipe is increasingly being used for gas transportation. Polyethylene pipe, with its lightweight, corrosion-resistant, and simple construction advantages, is widely used for medium- and low-pressure gas transportation, particularly in residential applications.

[0004] However, due to the performance limitations of the material itself, existing polyethylene pipes still have the following problems:

[0005] (1) Poor wear resistance: During the installation process of the pipeline, it will usually rub against the ground, other construction materials or tools. If the pipeline does not have good wear resistance, it will be easily scratched and worn during operations such as dragging and laying, thereby reducing the strength and sealing of the pipeline. The buried polyethylene gas pipeline will move relative to the surrounding soil. Especially in the case of soil settlement, geological activities, etc., long-term minor friction will gradually damage the surface of the pipeline. If the wear resistance of the pipeline is insufficient, it will be damaged, causing gas leakage and causing safety accidents. When the gas flows in the pipeline, it will have a certain scouring effect on the inner wall of the pipeline. Although the flow rate of gas is usually relatively low, it will also cause wear on the inner wall of the pipeline after long-term operation. Especially in some cases where the pressure fluctuation is large or the flow changes frequently, the scouring effect will be more obvious.

[0006] (2) Poor pressure resistance: Gas will generate a certain amount of pressure when it is transmitted in the pipeline. Polyethylene gas pipelines need to have sufficient strength to withstand this internal pressure to ensure that they will not break or deform under normal operating pressure. If the strength is insufficient, leakage will occur under the action of pressure, which will not only waste gas resources, but also bring safety hazards, such as fires, explosions and other dangerous situations. Buried polyethylene gas pipelines must withstand the covering pressure from the soil above. As the burial depth increases, the soil pressure will also increase accordingly. Low-strength pipelines are prone to deformation, affecting gas transportation. In the pipeline laying area, there may be external loads generated by construction activities or vehicle traffic. Low-strength polyethylene gas pipelines are difficult to withstand these accidental external forces and are easily damaged by external loads.

[0007] Polyethylene gas pipes with excellent wear resistance can better withstand the effects of various abrasive factors, thereby extending the pipe's service life. This not only reduces pipe replacement and maintenance costs, but also ensures the stability and safety of the gas supply. In the long run, wear resistance is a key guarantee for polyethylene gas pipes to maintain good performance throughout their entire service life. High-strength, pressure-resistant polyethylene gas pipes offer improved reliability and durability. Over long-term use, they can withstand a variety of complex environments and operating conditions, reducing the frequency of repairs and replacements due to pipe strength issues, thereby lowering maintenance costs and ensuring the long-term safety and stability of the gas supply. Therefore, wear resistance and pressure resistance are key performance indicators that urgently need to be improved in polyethylene pipes. Continuous research and development of pipe materials is needed to enhance performance, ensure gas transportation safety, and make them suitable for a wider range of environments, even meeting the higher requirements of high-pressure gas transportation, especially in industrial production. Summary of the Invention

[0008] Aiming at the problem that the existing polyethylene pipes have poor wear resistance and pressure resistance and cannot meet the needs of long-distance construction, long-term friction and high-pressure environment. The present invention provides a high-strength wear-resistant polyethylene gas pipeline and its preparation method, which uses high-density polyethylene, modified EPDM rubber, modified chlorinated polyethylene rubber, modified basalt fiber, silicon carbide ceramic material, magnesium oxide, lubricant, hindered amine light stabilizer, hindered phenol antioxidant, antistatic agent and the like as raw materials and compounded in a certain proportion; and according to the properties and dispersion characteristics of each component material, the mixing, mixing, extrusion and other process steps and parameters are designed, which can well realize the production of pipelines and obtain gas pipelines with uniform quality and excellent performance. It can greatly improve the compressive strength, impact resistance and wear resistance of the pipeline, and effectively improve the weather resistance of the pipeline, comprehensively improve the performance and service life of the pipeline, and is more suitable for use in various harsh environments. It can meet the needs of long-distance construction, long-term friction and high-pressure environment use, and can be widely used in high, medium and low pressure gas transportation, civil and industrial gas transportation. Its specific technical solution is as follows:

[0009] A high-strength wear-resistant polyethylene gas pipeline, comprising the following raw materials in parts by mass: 75 to 85 parts of high-density polyethylene, 6 to 10 parts of modified EPDM rubber, 3 to 5 parts of modified chlorinated polyethylene rubber, 8 to 12 parts of modified basalt fiber, 5 to 8 parts of silicon carbide ceramic material, 0.2 to 0.6 parts of magnesium oxide, 1.2 to 2 parts of lubricant, 0.2 to 0.5 parts of hindered amine light stabilizer, 0.1 to 0.5 parts of hindered phenol antioxidant, 0.5 to 1 part of antistatic agent; the modified EPDM rubber is an EPDM rubber modified by polyurethane, maleic anhydride grafted polymer and dioctyl phthalate; the modified chlorinated polyethylene rubber is a chlorinated polyethylene rubber modified by polyurethane, maleic anhydride grafted polymer and dioctyl phthalate; the modified basalt fiber is a basalt fiber with a composite surface modified by carbon black, potassium titanate whiskers, fumed silica and propylene glycol laurate.

[0010] Among the above raw materials, the index of the high-density polyethylene is: density 0.949g / cm 3 ~0.965g / cm 3 , crystallinity 80%~90%, softening point 125℃~135℃.

[0011] Among the above raw materials, the lubricant includes calcium stearate, zinc stearate and silicone powder, and the mass ratio is calcium stearate: zinc stearate: silicone powder = (2~5): (1~3): (1~3).

[0012] Among the above raw materials, the silicon carbide ceramic material is a powder obtained by crushing waste silicon carbide ceramics to obtain a particle size of less than 50 μm; the particle size of the magnesium oxide is less than 50 μm.

[0013] Among the above raw materials, the preparation method of the modified EPDM rubber comprises the following steps: according to the mass ratio of EPDM rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = (90-100): (6-12): (1-5): (5-10), the EPDM rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 65°C to 75°C to obtain the modified EPDM rubber.

[0014] Among the above raw materials, the preparation method of the modified chlorinated polyethylene rubber comprises the following steps: according to the mass ratio of chlorinated polyethylene rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = (90-100): (5-10): (1-5): (8-12), the chlorinated polyethylene rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 85°C to 95°C to obtain the modified chlorinated polyethylene rubber.

[0015] Among the above raw materials, the preparation method of the modified basalt fiber comprises the following steps: according to the mass ratio of basalt fiber: carbon black: potassium titanate whisker: fumed silica: propylene glycol laurate = (90-100): (1-3): (0.4-0.8): (2-5): (3-5), firstly uniformly mixing the potassium titanate whisker and the fumed silica with an air flow, then adding the carbon black, and continuing to mix with the air flow until uniform, to obtain an auxiliary material; diluting the propylene glycol laurate with ethanol to 4 to 5 times the mass to obtain a ball milling aid; wet-milling the basalt fiber and the ball milling aid for 10 to 15 minutes, then adding the auxiliary material, continuing the wet-milling for 10 to 20 minutes, discharging the material, and drying to remove the ethanol to obtain the modified basalt fiber.

[0016] In the above-mentioned method for preparing modified basalt fiber, the diameter of the basalt fiber ranges from 10 μm to 30 μm, and the length ranges from 1 mm to 3 mm.

[0017] In the above-mentioned method for preparing modified basalt fiber, the particle sizes of the carbon black, potassium titanate whiskers and fumed silica are all nanometer-scale.

[0018] The above-mentioned method for preparing a high-strength wear-resistant polyethylene gas pipeline comprises the following steps:

[0019] S1: mixing silicon carbide ceramic material, magnesium oxide, and lubricant according to parts by mass to obtain a mixture A;

[0020] S2: Mixing a hindered amine light stabilizer, a hindered phenol antioxidant, and an antistatic agent in parts by mass to obtain a mixture B;

[0021] S3: Drying the high-density polyethylene to remove moisture; adding high-density polyethylene, modified EPDM rubber, modified chlorinated polyethylene rubber, and mixture A into an internal mixer according to their mass fractions, and performing internal mixing at 140°C to 160°C, a speed of 60r / min to 80r / min, and a time of 5min to 10min; then adding modified basalt fiber and mixture B, and performing internal mixing at 160°C to 180°C, a speed of 100r / min to 120r / min, and a time of 15min to 20min to obtain an internal mixing material, and extruding the material into a shape through a single-screw or twin-screw extruder, and air-cooling to obtain a shaped pipe;

[0022] S4, placing the shaped pipe at 50℃~60℃ and letting it stand for 24h~30h to obtain a finished pipe.

[0023] In S3 of the above preparation method, the drying temperature is 80° C. to 95° C., and the drying time is 4 h to 6 h.

[0024] In S4 of the above preparation method, the extruder is divided into a feeding zone, a compression zone, a metering zone and a head zone: the temperature of the feeding zone is 140°C to 150°C, the temperature of the compression zone is 170°C to 180°C, the temperature of the metering zone is 160°C to 170°C, and the temperature of the head zone is 150°C to 160°C; the extrusion speed of the extruder is 0.5m / min to 1.5m / min.

[0025] The high-strength wear-resistant polyethylene gas pipeline and its preparation method provided by the present invention have the following beneficial effects compared with the prior art:

[0026] 1. The pipeline of the present invention adopts high-density polyethylene, modified EPDM rubber, modified chlorinated polyethylene rubber, modified basalt fiber, silicon carbide ceramic material, magnesium oxide, lubricant, hindered amine light stabilizer, hindered phenol antioxidant, antistatic agent and the like as raw materials; the various components are used in combination in a certain proportion, which can greatly improve the compressive strength, impact resistance and wear resistance of the pipeline, and effectively improve the weather resistance of the pipeline, comprehensively improve the performance and service life of the pipeline, and make it more suitable for use in various harsh environments.

[0027] Second, the present invention utilizes appropriate amounts of polyurethane, maleic anhydride grafted polymer, and dioctyl phthalate to modify EPDM rubber. Polyurethane increases the hardness and strength of the rubber, enabling it to withstand greater external forces. It also increases the heat resistance of the EPDM rubber to a certain extent, thereby improving the performance of the pipeline. The maleic anhydride grafted polymer forms chemical bonds with the EPDM rubber, enhancing the bonding between rubber molecules and thereby increasing the rubber's tensile and tear strength. Furthermore, the maleic anhydride grafted polymer improves the mixing compatibility of the EPDM rubber with high-density polyethylene (HDPE), reducing phase separation at high temperatures, thereby enhancing the rubber's heat resistance and improving the performance of the pipeline. Dioctyl phthalate can increase the toughness of rubber, can absorb energy when rubber is subjected to external force, reduce the generation and expansion of cracks, make it difficult to break when subjected to impact, in addition, dioctyl phthalate can reduce the viscosity of EPDM rubber, and then improve the banburying fusion of EPDM rubber and high-density polyethylene, make it easier to flow and shape during processing, and then improve the performance of pipeline use. The present invention adopts maleic anhydride grafted polymer and dioctyl phthalate to modify, can compositely enhance the compatibility of EPDM rubber with other materials, make EPDM rubber easier to disperse evenly when blended with other materials, improve processing efficiency and product quality. The present invention adopts polyurethane and dioctyl phthalate to modify in a certain proportion, can well balance the strength, toughness and wear resistance of EPDM rubber and high-density polyethylene, further improve toughness and wear resistance while effectively enhancing hardness and strength.

[0028] Furthermore, polyurethane and maleic anhydride grafted polymers form a protective film on the rubber surface, preventing chemical attack and enhancing corrosion resistance. EPDM rubber already has good chemical resistance, and the addition of these modifiers can further enhance its corrosion, aging, and weathering resistance, expanding its application range for pipelines.

[0029] Third, the present invention utilizes appropriate amounts of polyurethane, maleic anhydride grafted polymer, and dioctyl phthalate to modify chlorinated polyethylene rubber. Polyurethane can form a cross-linked structure within the rubber system, enhancing the bonding force between molecules, thereby imparting higher tensile strength and tear strength to the chlorinated polyethylene rubber. Polyurethane has high heat resistance and can transfer some of its heat resistance to the chlorinated polyethylene rubber, thereby increasing the rubber's heat-resistant temperature. Maleic anhydride grafted polymer can chemically react with the chlorinated polyethylene rubber to form strong chemical bonds, further enhancing the rubber's mechanical strength and chemical resistance. Maleic anhydride grafted polymer can improve the compatibility of the rubber with other materials and reduce phase separation at high temperatures, thereby enhancing the heat stability of the chlorinated polyethylene rubber, making it easier to disperse the rubber evenly during blending, and ensuring consistent product quality. Dioctyl phthalate can increase the rubber's toughness, making it less likely to break when impacted, thereby improving its impact resistance. Dioctyl phthalate can reduce the viscosity of the chlorinated polyethylene rubber, making it easier to flow and form during processing, thereby improving processing efficiency. The combination of polyurethane and maleic anhydride grafted polymer can effectively form a protective layer on the rubber surface, blocking the erosion of chemical substances, thereby improving the corrosion resistance and weather resistance of pipelines. The present invention adopts maleic anhydride grafted polymer and dioctyl phthalate to modify and enhance the compatibility of chlorinated polyethylene rubber with other materials, making it easier to disperse the chlorinated polyethylene rubber evenly when blended with other materials, thereby improving processing efficiency and product quality. The present invention adopts polyurethane and dioctyl phthalate to modify and enhance in a certain proportion, which can effectively balance the strength, toughness and wear resistance of chlorinated polyethylene rubber and high-density polyethylene, effectively enhancing hardness and strength while further improving toughness and wear resistance.

[0030] 4. The present invention uses carbon black, potassium titanate whiskers, fumed silica and propylene glycol laurate to carry out composite surface coating modification on basalt fiber. Carbon black coating modification can increase the hardness and strength of basalt fiber. Carbon black particles form a tiny reinforcing structure on the fiber surface, which can withstand greater external forces and improve the tensile strength and bending resistance of the fiber. Carbon black has good heat resistance and remains stable at high temperatures. The presence of carbon black can increase the heat resistance temperature of basalt fiber, so that it can still maintain good mechanical properties and dimensional stability in high temperature environments. Potassium titanate whiskers have high strength and rigidity and can effectively enhance the mechanical properties of basalt fiber. The three-dimensional network structure formed by the whiskers on the fiber surface can disperse external forces and reduce stress concentration, thereby improving the strength and toughness of the fiber. Potassium titanate whiskers have a high melting point and thermal stability and maintain the stability of their structure and performance at high temperatures. The addition of potassium titanate whiskers can improve the heat resistance of basalt fiber, so that it can be used at higher temperatures. Fumed silica can fill the tiny pores and defects on the fiber surface, making the fiber surface smoother and denser, and improving the strength and wear resistance of the fiber. Fumed silica can also improve the heat resistance of basalt fiber. Basalt fiber itself has a certain toughness. The present invention adopts carbon black, potassium titanate whiskers and fumed silica to carry out composite surface coating modification on basalt fiber, which can further improve its toughness. The synergistic effect of carbon black, potassium titanate whiskers and fumed silica can absorb energy when the fiber is subjected to external force, reduce the generation and expansion of cracks, and improve the impact resistance, fracture toughness and wear resistance of the fiber. The presence of carbon black, potassium titanate whiskers and fumed silica can increase the surface roughness of basalt fiber, improve the interfacial bonding force between the fiber and rubber and polyethylene components, and the rough surface can increase the mechanical intercalation between the fiber and other components, improve the bonding strength of the interface, thereby improving the mechanical properties of the composite material. Propylene glycol laurate can form a film on the surface of basalt fiber, reduce the friction coefficient, reduce friction and wear, and improve the wear resistance and durability of basalt fiber and pipes.

[0031] In addition, the present invention uses fumed silica to pre-mix and disperse potassium titanate whiskers and carbon black. Fumed silica has a good dispersing effect on potassium titanate whiskers and carbon black, making the ball-milled mixed coating distribution of potassium titanate whiskers and carbon black more uniform, thereby reducing weak parts and comprehensively improving pipeline performance. Propylene glycol laurate is used to prepare a ball milling aid, which can also effectively improve the ball milling mixed coating homogeneity, better disperse potassium titanate whiskers and carbon black, and improve the modified quality of basalt, with better modified homogeneity; it can also contribute to the dispersion homogeneity of basalt fiber in rubber and polyethylene, making the mixing quality more uniform, effectively reducing the generation of weak parts in the pipeline, and comprehensively improving pipeline performance. The present invention uses fumed silica and propylene glycol laurate in a certain proportion for wet ball milling, which has a synergistic effect, can better improve the modified distribution uniformity, and improve pipeline homogeneity. In addition, the present invention uses carbon black, potassium titanate whiskers, fumed silica and propylene glycol laurate to perform composite surface coating modification on basalt fiber, which can reduce the amount of auxiliary agents (coating agents) used, reduce the cost of materials, and at the same time enable the pipeline to achieve excellent mechanical properties.

[0032] 5. The combined use of magnesium oxide and silicone powder is highly effective in enhancing the mechanical properties of rubber and polyethylene plastics. Magnesium oxide acts as a crosslinker in rubber, increasing the bonding force between rubber molecules, thereby improving mechanical properties such as tensile strength and tear strength. Magnesium oxide has high thermal stability and can, to a certain extent, increase the heat resistance of pipes. Silicone powder has excellent lubricity and dispersibility, enabling the uniform dispersion of various fillers in rubber, further enhancing the rubber's strength. Silicone powder forms a protective film on the rubber surface, preventing heat transfer and oxygen penetration, further enhancing the pipe's heat resistance. The combination of magnesium oxide and silicone powder can increase the hardness and wear resistance of rubber and polyethylene plastics, reducing wear during use and extending the service life of the pipes. The combination of the two can also improve the pipe's impact resistance, reducing cracking and damage from impact.

[0033] 6. This invention utilizes process steps and parameters, including mixing, mixing, and extrusion, designed based on the properties and dispersion characteristics of each component material. This allows for efficient pipe production, resulting in uniform quality and superior performance. This gas pipeline can withstand long-distance construction, long-term friction, and high-pressure environments, and is widely applicable to high-, medium-, and low-pressure gas transportation, as well as civil and industrial gas transportation. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to specific implementation cases, but the present invention is not limited to these embodiments.

[0035] Example 1

[0036] A high-strength, wear-resistant polyethylene gas pipeline comprises the following raw materials in parts by mass: 80 parts of high-density polyethylene, 8 parts of modified EPDM rubber, 4 parts of modified chlorinated polyethylene rubber, 10 parts of modified basalt fiber, 6.5 parts of silicon carbide ceramic material, 0.4 parts of magnesium oxide, 1.6 parts of lubricant, 0.3 parts of hindered amine light stabilizer, 0.3 parts of hindered phenol antioxidant, and 0.8 parts of antistatic agent.

[0037] Among them, the indicators of high-density polyethylene are: density 0.954g / cm 3 , a crystallinity of 85.2%, and a softening point of 128°C. The lubricant comprises calcium stearate, zinc stearate, and silicone powder in a mass ratio of 3:2:2. The silicon carbide ceramic material is waste silicon carbide ceramic ground to a powder with a particle size of 50 μm or less; the magnesium oxide also has a particle size of 50 μm or less.

[0038] Among them, the preparation method of modified EPDM rubber includes the following steps: according to the mass ratio of EPDM rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 95:9:3:8, EPDM rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 70°C to obtain modified EPDM rubber.

[0039] Among the above raw materials, the preparation method of the modified chlorinated polyethylene rubber comprises the following steps: according to the mass ratio of chlorinated polyethylene rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 95:8:3:10, chlorinated polyethylene rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 90°C to obtain modified chlorinated polyethylene rubber.

[0040] Among the above raw materials, the preparation method of the modified basalt fiber includes the following steps: according to the mass ratio of basalt fiber: carbon black: potassium titanate whisker: fumed silica: propylene glycol laurate = 95:2:0.6:3:4, firstly mixing the potassium titanate whisker and fumed silica uniformly with air flow, then adding carbon black, and continuing to mix with air flow until uniform, to obtain an auxiliary material; diluting the propylene glycol laurate to 4.5 times its mass with ethanol to obtain a ball milling aid; wet-milling the basalt fiber and the ball milling aid for 12 minutes, then adding the auxiliary material, continuing to wet-mill for 15 minutes, discharging, drying and removing ethanol, to obtain modified basalt fiber.

[0041] In the above-mentioned method for preparing modified basalt fiber, the diameter of the basalt fiber ranges from 10 μm to 30 μm, and the length ranges from 1 mm to 3 mm.

[0042] In the above-mentioned method for preparing modified basalt fiber, the particle sizes of the carbon black, potassium titanate whiskers and fumed silica are all nanometer-scale.

[0043] The above-mentioned method for preparing a high-strength wear-resistant polyethylene gas pipeline comprises the following steps:

[0044] S1: mixing silicon carbide ceramic material, magnesium oxide, and lubricant according to parts by mass to obtain a mixture A;

[0045] S2: Mixing a hindered amine light stabilizer, a hindered phenol antioxidant, and an antistatic agent in parts by mass to obtain a mixture B;

[0046] S3: Dry the high-density polyethylene at 90°C for 5 hours to remove moisture; add the high-density polyethylene, modified EPDM rubber, modified chlorinated polyethylene rubber, and mixture A according to their mass fractions into an internal mixer, and perform internal mixing at 150°C, a speed of 70 r / min, and a time of 8 minutes; then add the modified basalt fiber and mixture B, and perform internal mixing at 170°C, a speed of 110 r / min, and a time of 18 minutes to obtain an internal mixing material, which is then extruded into a mold by a single-screw or twin-screw extruder, and air-cooled to obtain a shaped pipe;

[0047] The extruder is divided into a feeding zone, a compression zone, a metering zone, and a die zone. The temperature of the feeding zone is 145°C, the temperature of the compression zone is 175°C, the temperature of the metering zone is 165°C, and the temperature of the die zone is 155°C. The extrusion speed of the extruder is 1m / min.

[0048] S4, placing the shaped pipe at 55°C for 26 hours to obtain a finished pipe.

[0049] Example 2

[0050] A high-strength, wear-resistant polyethylene gas pipeline comprises the following raw materials in parts by mass: 75 parts of high-density polyethylene, 6 parts of modified EPDM rubber, 3 parts of modified chlorinated polyethylene rubber, 8 parts of modified basalt fiber, 5 parts of silicon carbide ceramic material, 0.2 parts of magnesium oxide, 1.2 parts of lubricant, 0.2 parts of hindered amine light stabilizer, 0.1 parts of hindered phenol antioxidant, and 0.5 parts of antistatic agent.

[0051] Among them, the indicators of high-density polyethylene are: density 0.949g / cm 3 , 80% crystallinity, and a softening point of 125°C. The lubricant includes calcium stearate, zinc stearate, and silicone powder in a mass ratio of 2:1:1. The silicon carbide ceramic material is waste silicon carbide ceramic ground to a powder with a particle size of 50 μm or less; the magnesium oxide also has a particle size of 50 μm or less.

[0052] Among them, the preparation method of modified EPDM rubber includes the following steps: according to the mass ratio of EPDM rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 90:6:1:5, EPDM rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 65°C to obtain modified EPDM rubber.

[0053] Among the above raw materials, the preparation method of the modified chlorinated polyethylene rubber comprises the following steps: according to the mass ratio of chlorinated polyethylene rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 90:5:1:8, chlorinated polyethylene rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 85°C to obtain modified chlorinated polyethylene rubber.

[0054] Among the above raw materials, the preparation method of the modified basalt fiber includes the following steps: according to the mass ratio of basalt fiber: carbon black: potassium titanate whisker: fumed silica: propylene glycol laurate = 90:1:0.4:2:3, firstly mixing the potassium titanate whisker and fumed silica uniformly with air flow, then adding carbon black, and continuing to mix with air flow until uniform, to obtain an auxiliary material; diluting the propylene glycol laurate to 4 times its mass with ethanol to obtain a ball milling aid; wet-milling the basalt fiber and the ball milling aid for 10 minutes, then adding the auxiliary material, continuing wet-milling for 10 minutes, discharging, drying and removing ethanol, to obtain modified basalt fiber.

[0055] In the above-mentioned method for preparing modified basalt fiber, the diameter of the basalt fiber ranges from 10 μm to 30 μm, and the length ranges from 1 mm to 3 mm.

[0056] In the above-mentioned method for preparing modified basalt fiber, the particle sizes of the carbon black, potassium titanate whiskers and fumed silica are all nanometer-scale.

[0057] The above-mentioned method for preparing a high-strength wear-resistant polyethylene gas pipeline comprises the following steps:

[0058] S1: mixing silicon carbide ceramic material, magnesium oxide, and lubricant according to parts by mass to obtain a mixture A;

[0059] S2: Mixing a hindered amine light stabilizer, a hindered phenol antioxidant, and an antistatic agent in parts by mass to obtain a mixture B;

[0060] S3: Dry the high-density polyethylene at 80°C for 4 hours to remove moisture; add the high-density polyethylene, modified EPDM rubber, modified chlorinated polyethylene rubber, and mixture A into an internal mixer according to their mass fractions, and perform internal mixing at 140°C, a speed of 60 r / min, and a time of 5 minutes; then add the modified basalt fiber and mixture B, and perform internal mixing at 160°C, a speed of 100 r / min, and a time of 15 minutes to obtain the internal mixing material, and extrude the material into a single-screw or twin-screw extruder, and air-cool it to obtain a shaped pipe;

[0061] The extruder is divided into a feeding zone, a compression zone, a metering zone, and a die zone. The temperature of the feeding zone is 140°C, the temperature of the compression zone is 170°C, the temperature of the metering zone is 160°C, and the temperature of the die zone is 150°C. The extrusion speed of the extruder is 0.5 m / min.

[0062] S4, placing the shaped pipe at 50°C for 24 hours to obtain a finished pipe.

[0063] Example 3

[0064] A high-strength, wear-resistant polyethylene gas pipeline comprises the following raw materials in parts by mass: 75 parts of high-density polyethylene, 10 parts of modified EPDM rubber, 3 parts of modified chlorinated polyethylene rubber, 12 parts of modified basalt fiber, 5 parts of silicon carbide ceramic material, 0.6 parts of magnesium oxide, 1.2 parts of lubricant, 0.5 parts of hindered amine light stabilizer, 0.1 parts of hindered phenol antioxidant, and 1 part of antistatic agent.

[0065] Among them, the indicators of high-density polyethylene are: density 0.952g / cm 3 , a crystallinity of 82.3%, and a softening point of 127°C. The lubricant comprises calcium stearate, zinc stearate, and silicone powder in a mass ratio of 2:3:1. The silicon carbide ceramic material is waste silicon carbide ceramic ground to a powder with a particle size of 50 μm or less; the magnesium oxide also has a particle size of 50 μm or less.

[0066] Among them, the preparation method of modified EPDM rubber includes the following steps: according to the mass ratio of EPDM rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 100:6:5:5, EPDM rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 75°C to obtain modified EPDM rubber.

[0067] Among the above raw materials, the preparation method of the modified chlorinated polyethylene rubber comprises the following steps: according to the mass ratio of chlorinated polyethylene rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 90:10:1:12, chlorinated polyethylene rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 85°C to obtain modified chlorinated polyethylene rubber.

[0068] Among the above raw materials, the preparation method of the modified basalt fiber includes the following steps: according to the mass ratio of basalt fiber: carbon black: potassium titanate whisker: fumed silica: propylene glycol laurate = 100:1:0.8:2:5, firstly mixing the potassium titanate whisker and fumed silica uniformly with air flow, then adding carbon black, and continuing to mix with air flow until uniform, to obtain an auxiliary material; diluting the propylene glycol laurate to 4 times its mass with ethanol to obtain a ball milling aid; wet-milling the basalt fiber and the ball milling aid for 15 minutes, then adding the auxiliary material, continuing wet-milling for 10 minutes, discharging, drying and removing ethanol, to obtain modified basalt fiber.

[0069] In the above-mentioned method for preparing modified basalt fiber, the diameter of the basalt fiber ranges from 10 μm to 30 μm, and the length ranges from 1 mm to 3 mm.

[0070] In the above-mentioned method for preparing modified basalt fiber, the particle sizes of the carbon black, potassium titanate whiskers and fumed silica are all nanometer-scale.

[0071] The above-mentioned method for preparing a high-strength wear-resistant polyethylene gas pipeline comprises the following steps:

[0072] S1: mixing silicon carbide ceramic material, magnesium oxide, and lubricant according to parts by mass to obtain a mixture A;

[0073] S2: Mixing a hindered amine light stabilizer, a hindered phenol antioxidant, and an antistatic agent in parts by mass to obtain a mixture B;

[0074] S3: Dry the high-density polyethylene at 95°C for 4 hours to remove moisture; add the high-density polyethylene, modified EPDM rubber, modified chlorinated polyethylene rubber, and mixture A according to their mass fractions into an internal mixer, and perform internal mixing at 160°C, a speed of 60 r / min, and a time of 10 minutes; then add the modified basalt fiber and mixture B, and perform internal mixing at 160°C, a speed of 120 r / min, and a time of 15 minutes to obtain an internal mixing material, which is extruded into a shape by a single-screw or twin-screw extruder, and air-cooled to obtain a shaped pipe;

[0075] The extruder is divided into a feeding zone, a compression zone, a metering zone, and a die zone. The temperature of the feeding zone is 150°C, the temperature of the compression zone is 170°C, the temperature of the metering zone is 170°C, and the temperature of the die zone is 150°C. The extrusion speed of the extruder is 1.5 m / min.

[0076] S4, placing the shaped pipe at 50°C for 30 hours to obtain a finished pipe.

[0077] Example 4

[0078] A high-strength, wear-resistant polyethylene gas pipeline comprises the following raw materials in parts by mass: 85 parts of high-density polyethylene, 10 parts of modified EPDM rubber, 5 parts of modified chlorinated polyethylene rubber, 12 parts of modified basalt fiber, 8 parts of silicon carbide ceramic material, 0.6 parts of magnesium oxide, 2 parts of lubricant, 0.5 parts of hindered amine light stabilizer, 0.5 parts of hindered phenol antioxidant, and 1 part of antistatic agent.

[0079] Among them, the indicators of high-density polyethylene are: density 0.965g / cm 3 , 90% crystallinity, and a softening point of 135°C. The lubricant comprises calcium stearate, zinc stearate, and silicone powder in a mass ratio of 5:3:3. The silicon carbide ceramic material is waste silicon carbide ceramic ground to a powder with a particle size of 50 μm or less; the magnesium oxide also has a particle size of 50 μm or less.

[0080] Among them, the preparation method of modified EPDM rubber includes the following steps: according to the mass ratio of EPDM rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 100:12:5:10, EPDM rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 75°C to obtain modified EPDM rubber.

[0081] Among the above raw materials, the preparation method of the modified chlorinated polyethylene rubber comprises the following steps: according to the mass ratio of chlorinated polyethylene rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 100:10:5:12, chlorinated polyethylene rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 95°C to obtain modified chlorinated polyethylene rubber.

[0082] Among the above raw materials, the preparation method of the modified basalt fiber includes the following steps: according to the mass ratio of basalt fiber: carbon black: potassium titanate whisker: fumed silica: propylene glycol laurate = 100:3:0.8:5:5, firstly mixing the potassium titanate whisker and fumed silica uniformly with air flow, then adding carbon black, and continuing to mix with air flow until uniform, to obtain an auxiliary material; diluting the propylene glycol laurate to 5 times its mass with ethanol to obtain a ball milling aid; wet-milling the basalt fiber and the ball milling aid for 15 minutes, then adding the auxiliary material, continuing wet-milling for 20 minutes, discharging, drying and removing ethanol, to obtain modified basalt fiber.

[0083] In the above-mentioned method for preparing modified basalt fiber, the diameter of the basalt fiber ranges from 10 μm to 30 μm, and the length ranges from 1 mm to 3 mm.

[0084] In the above-mentioned method for preparing modified basalt fiber, the particle sizes of the carbon black, potassium titanate whiskers and fumed silica are all nanometer-scale.

[0085] The above-mentioned method for preparing a high-strength wear-resistant polyethylene gas pipeline comprises the following steps:

[0086] S1: mixing silicon carbide ceramic material, magnesium oxide, and lubricant according to parts by mass to obtain a mixture A;

[0087] S2: Mixing a hindered amine light stabilizer, a hindered phenol antioxidant, and an antistatic agent in parts by mass to obtain a mixture B;

[0088] S3: Dry the high-density polyethylene at 95°C for 6 hours to remove moisture; add the high-density polyethylene, modified EPDM rubber, modified chlorinated polyethylene rubber, and mixture A according to their mass fractions into an internal mixer, and perform internal mixing at 160°C, a speed of 80 r / min, and a time of 10 minutes; then add the modified basalt fiber and mixture B, and perform internal mixing at 180°C, a speed of 120 r / min, and a time of 20 minutes to obtain an internal mixing material, which is extruded into a single-screw or twin-screw extruder, and air-cooled to obtain a shaped pipe;

[0089] The extruder is divided into a feeding zone, a compression zone, a metering zone, and a die zone. The temperature of the feeding zone is 150°C, the temperature of the compression zone is 180°C, the temperature of the metering zone is 170°C, and the temperature of the die zone is 160°C. The extrusion speed of the extruder is 1.5 m / min.

[0090] S4, placing the shaped pipe at 60°C for 30 hours to obtain a finished pipe.

[0091] Example 5

[0092] A high-strength, wear-resistant polyethylene gas pipeline comprises the following raw materials in parts by mass: 85 parts of high-density polyethylene, 6 parts of modified EPDM rubber, 5 parts of modified chlorinated polyethylene rubber, 8 parts of modified basalt fiber, 8 parts of silicon carbide ceramic material, 0.2 parts of magnesium oxide, 2 parts of lubricant, 0.2 parts of hindered amine light stabilizer, 0.5 parts of hindered phenol antioxidant, and 0.5 parts of antistatic agent.

[0093] Among them, the indicators of high-density polyethylene are: density 0.960g / cm 3 The lubricant comprises calcium stearate, zinc stearate, and silicone powder in a mass ratio of 5:1:3. The silicon carbide ceramic material is waste silicon carbide ceramic ground to a powder with a particle size of 50 μm or less. The magnesium oxide also has a particle size of 50 μm or less.

[0094] Among them, the preparation method of modified EPDM rubber includes the following steps: according to the mass ratio of EPDM rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 90:12:1:10, EPDM rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 65°C to obtain modified EPDM rubber.

[0095] Among the above raw materials, the preparation method of the modified chlorinated polyethylene rubber comprises the following steps: according to the mass ratio of chlorinated polyethylene rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 100:5:5:8, chlorinated polyethylene rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 95°C to obtain modified chlorinated polyethylene rubber.

[0096] Among the above raw materials, the preparation method of the modified basalt fiber includes the following steps: according to the mass ratio of basalt fiber: carbon black: potassium titanate whisker: fumed silica: propylene glycol laurate = 90:3:0.4:5:3, firstly mixing the potassium titanate whisker and fumed silica uniformly with air flow, then adding carbon black, and continuing to mix with air flow until uniform, to obtain an auxiliary material; diluting the propylene glycol laurate to 5 times its mass with ethanol to obtain a ball milling aid; wet-milling the basalt fiber and the ball milling aid for 10 minutes, then adding the auxiliary material, continuing wet-milling for 20 minutes, discharging, drying and removing ethanol, to obtain modified basalt fiber.

[0097] In the above-mentioned method for preparing modified basalt fiber, the diameter of the basalt fiber ranges from 10 μm to 30 μm, and the length ranges from 1 mm to 3 mm.

[0098] In the above-mentioned method for preparing modified basalt fiber, the particle sizes of the carbon black, potassium titanate whiskers and fumed silica are all nanometer-scale.

[0099] The above-mentioned method for preparing a high-strength wear-resistant polyethylene gas pipeline comprises the following steps:

[0100] S1: mixing silicon carbide ceramic material, magnesium oxide, and lubricant according to parts by mass to obtain a mixture A;

[0101] S2: Mixing a hindered amine light stabilizer, a hindered phenol antioxidant, and an antistatic agent in parts by mass to obtain a mixture B;

[0102] S3: Dry the high-density polyethylene at 80°C for 6 hours to remove moisture; add the high-density polyethylene, modified EPDM rubber, modified chlorinated polyethylene rubber, and mixture A into an internal mixer according to their mass fractions, and perform internal mixing at 140°C, a speed of 80 r / min, and a time of 5 minutes; then add the modified basalt fiber and mixture B, and perform internal mixing at 180°C, a speed of 100 r / min, and a time of 20 minutes to obtain an internal mixing material, which is extruded into a single-screw or twin-screw extruder, and air-cooled to obtain a shaped pipe;

[0103] The extruder is divided into a feeding zone, a compression zone, a metering zone, and a die zone. The temperature of the feeding zone is 145°C, the temperature of the compression zone is 172°C, the temperature of the metering zone is 164°C, and the temperature of the die zone is 156°C. The extrusion speed of the extruder is 1.2 m / min.

[0104] S4, placing the shaped pipe at 55°C for 28 hours to obtain a finished pipe.

[0105] Example 6

[0106] A high-strength, wear-resistant polyethylene gas pipeline comprises the following raw materials in parts by mass: 82 parts of high-density polyethylene, 7 parts of modified EPDM rubber, 3.5 parts of modified chlorinated polyethylene rubber, 11 parts of modified basalt fiber, 6 parts of silicon carbide ceramic material, 0.3 parts of magnesium oxide, 1.5 parts of lubricant, 0.4 parts of hindered amine light stabilizer, 0.3 parts of hindered phenol antioxidant, and 0.6 parts of antistatic agent.

[0107] Among them, the indicators of high-density polyethylene are: density 0.957g / cm 3 , a crystallinity of 84.7%, and a softening point of 129°C. The lubricant comprises calcium stearate, zinc stearate, and silicone powder in a mass ratio of 4:1:3. The silicon carbide ceramic material is waste silicon carbide ceramic ground to a powder with a particle size of less than 50 μm; the magnesium oxide also has a particle size of less than 50 μm.

[0108] Among them, the preparation method of modified EPDM rubber includes the following steps: according to the mass ratio of EPDM rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 98:8:4:6, EPDM rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 72°C to obtain modified EPDM rubber.

[0109] Among the above raw materials, the preparation method of the modified chlorinated polyethylene rubber comprises the following steps: according to the mass ratio of chlorinated polyethylene rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = 95:8:4:9, chlorinated polyethylene rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate are mixed at 92°C to obtain modified chlorinated polyethylene rubber.

[0110] Among the above raw materials, the preparation method of the modified basalt fiber includes the following steps: according to the mass ratio of basalt fiber: carbon black: potassium titanate whisker: fumed silica: propylene glycol laurate = 94:2:0.5:3:3, firstly mixing the potassium titanate whisker and fumed silica uniformly with air flow, then adding carbon black, and continuing to mix with air flow until uniform, to obtain an auxiliary material; diluting the propylene glycol laurate to 5 times its mass with ethanol to obtain a ball milling aid; wet-milling the basalt fiber and the ball milling aid for 10 minutes, then adding the auxiliary material, continuing wet-milling for 15 minutes, discharging, drying and removing ethanol, to obtain modified basalt fiber.

[0111] In the above-mentioned method for preparing modified basalt fiber, the diameter of the basalt fiber ranges from 10 μm to 30 μm, and the length ranges from 1 mm to 3 mm.

[0112] In the above-mentioned method for preparing modified basalt fiber, the particle sizes of the carbon black, potassium titanate whiskers and fumed silica are all nanometer-scale.

[0113] The above-mentioned method for preparing a high-strength wear-resistant polyethylene gas pipeline comprises the following steps:

[0114] S1: mixing silicon carbide ceramic material, magnesium oxide, and lubricant according to parts by mass to obtain a mixture A;

[0115] S2: Mixing a hindered amine light stabilizer, a hindered phenol antioxidant, and an antistatic agent in parts by mass to obtain a mixture B;

[0116] S3: Dry the high-density polyethylene at 95°C for 5 hours to remove moisture; add the high-density polyethylene, modified EPDM rubber, modified chlorinated polyethylene rubber, and mixture A according to their mass fractions into an internal mixer, and perform internal mixing at 155°C, a speed of 80 r / min, and a time of 6 minutes; then add the modified basalt fiber and mixture B, and perform internal mixing at 175°C, a speed of 120 r / min, and a time of 15 minutes to obtain an internal mixing material, which is then extruded into a mold by a single-screw or twin-screw extruder, and air-cooled to obtain a shaped pipe;

[0117] The extruder is divided into a feeding zone, a compression zone, a metering zone, and a die zone. The temperature of the feeding zone is 150°C, the temperature of the compression zone is 175°C, the temperature of the metering zone is 168°C, and the temperature of the die zone is 155°C. The extrusion speed of the extruder is 0.8 m / min.

[0118] S4, placing the shaped pipe at 55°C for 28 hours to obtain a finished pipe.

[0119] The model of the high-density polyethylene used in the above embodiments is 5000S, Suzhou Sutu Plastic New Material Co., Ltd.; the model of the hindered amine light stabilizer is UV-770, Dongguan Kangjin New Material Technology Co., Ltd.; the model of the hindered phenol antioxidant is Y-1010, Dongguan Kangjin New Material Technology Co., Ltd.; the model of the maleic anhydride grafted polymer is 9901, Dongguan Kangjin New Material Technology Co., Ltd.; the model of the antistatic agent is ZR-550, Shanghai Zirun Chemical Additive Co., Ltd.; the model of the EPDM rubber is 3080P, Jilin Petrochemical Branch of China National Petroleum Corporation; the model of the chlorinated polyethylene rubber is CPE-135A, Shijiazhuang Duobo Chemical Technology Co., Ltd.

[0120] Comparative Example 1

[0121] The EPDM rubber was not modified; the modified EPDM rubber was replaced by EPDM rubber; other methods and parameters were the same as those in Example 1.

[0122] Comparative Example 2

[0123] The chlorinated polyethylene rubber was not modified; the modified chlorinated polyethylene rubber was replaced by chlorinated polyethylene rubber; other methods and parameters were the same as in Example 1.

[0124] Comparative Example 3

[0125] Neither EPDM rubber nor chlorinated polyethylene rubber was modified; modified EPDM rubber was replaced by EPDM rubber, and modified chlorinated polyethylene rubber was replaced by chlorinated polyethylene rubber; other methods and parameters were the same as in Example 1.

[0126] Comparative Example 4

[0127] The EPDM rubber was modified without adding polyurethane and dioctyl phthalate; the chlorinated polyethylene rubber was modified without adding polyurethane and dioctyl phthalate; other methods and parameters were the same as in Example 1.

[0128] Comparative Example 5

[0129] The basalt fiber was not modified, and the modified basalt fiber was replaced by basalt fiber; other methods and parameters were the same as those in Example 1.

[0130] Comparative Example 6

[0131] In the preparation method of the modified basalt fiber, propylene glycol laurate is not added, and no ball milling aid is prepared, that is, the modification is performed by dry ball milling; other methods and parameters are the same as in Example 1.

[0132] Comparative Example 7

[0133] In the preparation method of the modified basalt fiber, no fumed silica and propylene glycol laurate were added, and no ball milling aid was prepared, that is, dry ball milling was used for modification; other methods and parameters were the same as in Example 1.

[0134] Comparative Example 8

[0135] No magnesium oxide was added to the raw materials, and no silicone powder was added to the lubricant; in 1.6 parts of the lubricant, the mass ratio of calcium stearate:zinc stearate=3:2; other methods and parameters were the same as in Example 1.

[0136] Comparative Example 9

[0137] The EPDM rubber, chlorinated polyethylene rubber, and basalt fiber were not modified in advance; the improvers, polyurethane, maleic anhydride grafted polymer, dioctyl phthalate, carbon black, potassium titanate whiskers, fumed silica, and propylene glycol laurate, were directly involved in the mixing and kneading of the mixture A. Other methods and parameters were the same as those in Example 1.

[0138] Comparative Example 10

[0139] Conventional polyethylene gas pipes on the market (polyethylene accounts for 96%) have an outer diameter of 32mm and a thickness of 4mm.

[0140] The materials of the above-mentioned embodiments and comparative examples were prepared into test samples and subjected to the following performance tests.

[0141] (1) Wear resistance test method: Prepare the extruded sample with a thickness of 4 mm on a flat plate; use a wear tester with an H-18 grinding wheel, apply a load of 800 g, rotate at a speed of 60 r / min, and rotate for a total of 800 revolutions; make three parallel samples for each type; weigh them before and after the test, and calculate the weight loss rate. The smaller the weight loss rate, the better the wear resistance.

[0142] (2) Compressive strength test method: The sample specification is a pipe with an outer diameter of 32 mm and a thickness of 4 mm; a pressure testing machine is used to test the compressive deformation strength; 3 parallel samples are made for each type.

[0143] (3) Impact resistance test method: The specimen specifications are pipes with an outer diameter of 32 mm and a thickness of 4 mm. The test is conducted according to the drop hammer method of GB / T14152, with the drop hammer weight being 12 kg and 14 kg at a height of 2 m. Ten parallel samples are made for each type, and the number of cracks is counted.

[0144] (4) Hardness test method: The sample specification is a pipe with an outer diameter of 32 mm and a thickness of 4 mm; the hardness test is performed using a Shore D hardness tester; 3 parallel samples are made for each type.

[0145] (5) Tensile strength test method: The sample specification is a pipe with an outer diameter of 32 mm and a thickness of 4 mm; a universal material testing machine is used for tensile strength testing; three parallel samples are made for each type.

[0146] (6) Elongation at break test method: The sample specification is a pipe with an outer diameter of 32 mm and a thickness of 4 mm; a universal material testing machine is used to test the elongation at break; three parallel samples are made for each type.

[0147] (7) Weathering resistance test method: The specimen specifications are pipes with an outer diameter of 32 mm and a thickness of 4 mm. Three sections of each pipe are selected and subjected to light aging using a xenon arc lamp aging test chamber with a light intensity of 0.55 W / m² / nm (340 nm). The temperature is 50°C and the humidity is 70%. Water is sprayed for 10 minutes every 2 hours. After 30 days, the compressive strength, hardness, tensile strength, and elongation at break are tested. The change rate of compressive strength, hardness, tensile strength, and elongation at break after aging is calculated to evaluate weathering resistance. Change rate (reduction rate) = (pre-test value - post-test value) / pre-test value × 100%.

[0148] The average detection results are shown in Tables 1 and 2 below.

[0149] Table 1 Test results of the embodiment

[0150] From the above results, it can be seen that the samples of Examples 1 to 6 have good wear resistance, and have high compressive strength, impact resistance, tensile strength, weather resistance and other indicators; they can effectively improve the performance and service life of the pipeline.

[0151] Table 2 Comparative Example Test Results

[0152] Comparing the results of Comparative Examples 1 to 3 with those of Example 1, it is clear that modifying EPDM rubber and chlorinated polyethylene rubber with polyurethane, maleic anhydride grafted polymer, and dioctyl phthalate, respectively, can improve various pipe properties. The combined use of modified EPDM rubber and modified chlorinated polyethylene rubber can significantly enhance pipe performance, demonstrating a synergistic effect. Comparing the results of Comparative Example 4 with those of Example 1, it is clear that the combined modification of polyurethane and dioctyl phthalate can enhance the strength and wear resistance of the rubber component. Mixing and kneading can further improve the strength and wear resistance of the polyethylene, thereby enhancing the strength and wear resistance of the pipe. Comparing the results of Comparative Example 5 with those of Example 1, it is clear that composite surface modification of basalt fiber using carbon black, potassium titanate whiskers, fumed silica, and propylene glycol laurate can significantly improve the mechanical properties of the basalt fiber, as well as the mechanical properties of the plastic and rubber components, even at relatively low dosages. Comparing the results of Comparative Example 6 with those of Example 1, it can be seen that the use of propylene glycol laurate as a ball milling aid can improve the modified quality of basalt and improve the modified homogeneity. After adding it to the banbury, the basalt is more evenly distributed, which can effectively reduce the occurrence of weak parts in the pipeline, thereby improving the mechanical properties of the pipeline. Comparing the results of Comparative Example 7 with those of Example 1, it can be seen that the combination of fumed silica and propylene glycol laurate has better effects on improving the uniformity of modified distribution, improving pipeline homogeneity, and improving overall performance, and fumed silica has the effect of further enhancing pipeline performance. Comparing the results of Comparative Example 8 with those of Example 1, it can be seen that the combination of magnesium oxide and silicone powder has a good effect on enhancing the mechanical properties of rubber and polyethylene plastics. Comparing the results of Comparative Example 9 with those of Example 1 shows that the unmodified EPDM rubber, CPE rubber, and basalt fiber were not pre-modified, and all modified raw materials were directly mixed and kneaded. The resulting pipe material had poor homogeneity, and the modifier's performance-enhancing effects on the EPDM rubber, CPE rubber, and basalt fiber were significantly weakened, particularly the mechanical properties of the basalt fiber, resulting in a significant decrease in various pipe performance properties. Comparing the results of Comparative Example 10 with those of Example 1 shows that the gas pipeline of the present invention has significantly superior performance compared to conventional polyethylene gas pipelines, significantly extending its service life and making it more suitable for use in various harsh environments.

Claims

1. A high-strength wear-resistant polyethylene gas pipeline, characterized in that: The pipeline includes the following raw materials in parts by weight: 75 to 85 parts of high-density polyethylene, 6 to 10 parts of modified EPDM rubber, 3 to 5 parts of modified chlorinated polyethylene rubber, 8 to 12 parts of modified basalt fiber, 5 to 8 parts of silicon carbide ceramic material, 0.2 to 0.6 parts of magnesium oxide, 1.2 to 2 parts of lubricant, 0.2 to 0.5 parts of hindered amine light stabilizer, 0.1 to 0.5 parts of hindered phenol antioxidant, and 0.5 to 1 parts of antistatic agent; The modified EPDM rubber is an EPDM rubber modified by polyurethane, maleic anhydride grafted polymer and dioctyl phthalate; the modified chlorinated polyethylene rubber is a chlorinated polyethylene rubber modified by polyurethane, maleic anhydride grafted polymer and dioctyl phthalate; and the modified basalt fiber is a basalt fiber with a composite surface modified by carbon black, potassium titanate whiskers, fumed silica and propylene glycol laurate.

2. A high-strength wear-resistant polyethylene gas pipeline according to claim 1, characterized in that: The index of the high-density polyethylene is: density 0.949g / cm 3 ~0.965g / cm 3 , crystallinity 80%~90%, softening point 125℃~135℃.

3. The high-strength wear-resistant polyethylene gas pipeline according to claim 1, characterized in that: The lubricant comprises calcium stearate, zinc stearate and silicone powder, and the mass ratio of calcium stearate:zinc stearate:silicone powder is (2-5):(1-3):(1-3).

4. The high-strength wear-resistant polyethylene gas pipeline according to claim 1, characterized in that: The silicon carbide ceramic material is a powder obtained by crushing waste silicon carbide ceramics to obtain a particle size of less than 50 μm; the particle size of the magnesium oxide is less than 50 μm.

5. The high-strength wear-resistant polyethylene gas pipeline according to claim 1, characterized in that: The preparation method of the modified EPDM rubber comprises the following steps: mixing the EPDM rubber, the polyurethane, the maleic anhydride grafted polymer and the dioctyl phthalate at 65° C. to 75° C. according to the mass ratio of EPDM rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = (90-100): (6-12): (1-5): (5-10) to obtain the modified EPDM rubber.

6. The high-strength wear-resistant polyethylene gas pipeline according to claim 1, characterized in that: The preparation method of the modified chlorinated polyethylene rubber comprises the following steps: mixing the chlorinated polyethylene rubber, polyurethane, maleic anhydride grafted polymer and dioctyl phthalate at 85° C. to 95° C. in a mass ratio of chlorinated polyethylene rubber: polyurethane: maleic anhydride grafted polymer: dioctyl phthalate = (90-100): (5-10): (1-5): (8-12) to obtain the modified chlorinated polyethylene rubber.

7. The high-strength wear-resistant polyethylene gas pipeline according to claim 1, characterized in that: The preparation method of the modified basalt fiber comprises the following steps: according to the mass ratio of basalt fiber: carbon black: potassium titanate whisker: fumed silica: propylene glycol laurate = (90-100): (1-3): (0.4-0.8): (2-5): (3-5), firstly, the potassium titanate whisker and the fumed silica are uniformly mixed by air flow, then the carbon black is added, and the air flow mixing is continued until uniform to obtain an auxiliary material; the propylene glycol laurate is diluted to 4 to 5 times the mass by ethanol to obtain a ball milling aid; the basalt fiber and the ball milling aid are wet-milled for 10 to 15 minutes, then the auxiliary material is added, the wet-milling is continued for 10 to 20 minutes, the material is discharged, and the ethanol is removed by drying to obtain the modified basalt fiber.

8. The high-strength wear-resistant polyethylene gas pipeline according to claim 7, characterized in that: The diameter of the basalt fiber is in the range of 10 μm to 30 μm, and the length is in the range of 1 mm to 3 mm; the particle sizes of the carbon black, potassium titanate whisker and fumed silica are all in nanometer level.

9. A method for preparing a high-strength wear-resistant polyethylene gas pipeline, used for preparing the high-strength wear-resistant polyethylene gas pipeline according to claim 1, characterized in that: The preparation method comprises the following steps: S1: mixing silicon carbide ceramic material, magnesium oxide and lubricant according to weight proportions to obtain a mixture A; S2: Mixing the hindered amine light stabilizer, the hindered phenol antioxidant and the antistatic agent according to their weight percentage to obtain a mixture B; S3: Dry the high-density polyethylene to remove moisture; add the high-density polyethylene, modified EPDM rubber, modified chlorinated polyethylene rubber, and mixture A into an internal mixer according to the mass fraction, and perform internal mixing at 140°C to 160°C, with a rotation speed of 60r / min to 80r / min, for 5min to 10min, then add the modified basalt fiber and mixture B, perform internal mixing at 160°C to 180°C, with a rotation speed of 100r / min to 120r / min, for 15min to 20min, and obtain the internal mixing material, and extrude and shape it through a single-screw or twin-screw extruder, and air-cool it to obtain a shaped pipe; S4, placing the shaped pipe at 50℃~60℃ and leaving it to stand for 24h~30h to obtain a finished pipe.

10. The method for preparing a high-strength wear-resistant polyethylene gas pipeline according to claim 9, characterized in that: In S3, the drying temperature is 80℃~95℃, and the drying time is 4h~6h; in S4, the extruder is divided into a feeding zone, a compression zone, a metering zone and a head zone: the temperature of the feeding zone is 140℃~150℃, the temperature of the compression zone is 170℃~180℃, the temperature of the metering zone is 160℃~170℃, and the temperature of the head zone is 150℃~160℃; the extrusion speed of the extruder is 0.5m / min~1.5m / min.

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