Anti-ultraviolet and anti-aging PE threaded pipe and preparation method thereof

Abstract

The application belongs to the technical field of threaded pipes, and discloses an anti-ultraviolet and anti-aging PE threaded pipe and a preparation method thereof. The application comprises the following raw materials in parts by mass: PE100 resin 100-110 parts, maleic anhydride grafted polyethylene 1.5-2.2 parts, polyethylene wax 0.7-1.5 parts, aluminum hydroxide 4-6 parts, magnesium hydroxide 4-6 parts, ultraviolet shielding agent 3-5 parts, modified basalt fiber 5-8 parts, synergistic microspheres 4-6 parts, antioxidant 3114 0.3-0.5 parts, antioxidant 168 0.3-0.5 parts, and color master batch 1-2 parts. The introduction of the ultraviolet shielding agent, the modified basalt fiber and the synergistic microspheres effectively improves the impact resistance, low-temperature impact resistance, tensile strength, weather resistance and anti-aging property of the PE threaded pipe. Therefore, the application has a more extensive application prospect.

Description

Technical Field

[0001] This invention belongs to the field of threaded pipe technology, specifically relating to an UV-resistant and aging-resistant PE threaded pipe and its preparation method. Background Technology

[0002] Polyethylene pipe, or PE pipe for short, is a type of pipe made from non-polar thermoplastic resin. It is non-toxic, tasteless, and odorless. Pipes made from polyethylene are convenient to transport and install, have good mechanical properties, good chemical stability, strong insulation, and low transmission loss. They are widely used in many fields such as tap water transportation, sewage discharge, gas transmission, and electrical wire insulation. Especially in sewage transportation, the excellent corrosion resistance and mechanical strength of polyethylene pipes enable them to cope with many complex sewage compositions and discharge environments. PE threaded pipe is a type of pipe product made primarily of polyethylene (PE) and processed through a special process to form a spiral thread structure. Its core characteristics are high strength, corrosion resistance, and ease of installation, making it widely used in industrial transportation, agricultural irrigation, and other fields.

[0003] However, in practical applications, PE threaded pipes still have problems such as easy cracking at the root of the thread when subjected to transportation bumps, construction collisions, or fluid impacts, leading to pipe leakage; and the pipe body is prone to low-temperature brittleness fracture when the ambient temperature is below -10℃, thread deformation or tensile fracture under long-term stress, mechanical property degradation due to ultraviolet aging, and thermo-oxidative degradation in high-temperature environments, leading to brittleness. Therefore, the impact resistance, low-temperature impact resistance, tensile strength, weather resistance, and aging resistance of existing PE threaded pipes still need to be improved. Summary of the Invention

[0004] To address the shortcomings mentioned in the background section, the present invention aims to provide an UV-resistant and aging-resistant PE threaded pipe and its preparation method, thereby solving the following technical problems: Existing PE threaded pipes still have problems with poor impact resistance, low-temperature impact resistance, tensile strength, weather resistance, and aging resistance.

[0005] The objective of this invention can be achieved through the following technical solutions: A UV-resistant and aging-resistant PE threaded pipe comprises the following raw materials in parts by weight: 100-110 parts PE100 resin, 1.5-2.2 parts maleic anhydride grafted polyethylene, 0.7-1.5 parts polyethylene wax, 4-6 parts aluminum hydroxide, 4-6 parts magnesium hydroxide, 3-5 parts UV shielding agent, 5-8 parts modified basalt fiber, 4-6 parts synergistic microspheres, 0.3-0.5 parts antioxidant 3114, 0.3-0.5 parts antioxidant 168, and 1-2 parts color masterbatch; The ultraviolet shielding agent is made from KH-550 modified nano-titanium dioxide and hollow glass microspheres; The modified basalt fiber is a basalt fiber that has undergone carbon deposition and then been modified with silane coupling agent KH-550. The enhanced microspheres are composite microspheres with a core of polycaprolactone, isophorone diisocyanate, and 2-hydroxyethyl disulfide polyurethane prepolymer extended by ethylenediamine, and a shell of methyl methacrylate and maleic anhydride copolymer.

[0006] Preferably, the method for preparing the ultraviolet shielding agent is as follows: A1: Add deionized water and silane coupling agent KH-550 to anhydrous ethanol and stir for 10-20 min. Then adjust the pH to 4-5 with acetic acid, add nano titanium dioxide and ultrasonically disperse for 30-50 min. Then stir at 58-60℃ for 2-3 h to obtain a pretreated titanium dioxide suspension. A2: Hollow glass microspheres were added to deionized water and the pH was adjusted to 4 with acetic acid. Then, the pretreated titanium dioxide suspension was added dropwise at 10 g / min while stirring at 800-1000 r / min. The pH was then adjusted to 8.5 with ammonia. The mixture was stirred at 65℃ for 4-5 h. After cooling to room temperature, the mixture was filtered and the precipitate was washed 4 times alternately with deionized water and anhydrous ethanol. After vacuum drying at 80℃ and -0.095 MPa for 8-9 h, the mixture was pulverized and passed through an 800-mesh sieve to obtain the ultraviolet shielding agent.

[0007] Preferably, the mass ratio of anhydrous ethanol, deionized water, silane coupling agent KH-550, and nano titanium dioxide in A1 is 500:30-50:5:100; The mass ratio of deionized water, hollow glass microspheres, and pretreated titanium dioxide suspension in A2 is 800:150:250-350.

[0008] Preferably, the modified basalt fiber is prepared as follows: B1: Basalt fiber is added to ferric nitrate ethanol solution and stirred for 30-50 min. Then, it is centrifuged and dried at 80-100℃ for 2-3 h. Then, the temperature is increased to 350℃ at 5℃ / min and held for 1-1.2 h. Then, it is heated to 650℃ under nitrogen atmosphere and held for 30-40 min. Then, a mixture of methane and hydrogen gas is introduced. After 4-6 h, it is cooled to room temperature under nitrogen atmosphere to obtain pretreated basalt fiber. B2: Add deionized water and silane coupling agent KH-550 to anhydrous ethanol and stir for 10-20 min. Then adjust the pH to 4-5 with acetic acid, add pretreated basalt fiber and ultrasonically disperse for 30-50 min. Stir at 58-60℃ for 2-3 h, centrifuge and vacuum dry at 80℃ and -0.09MPa for 4-6 h to obtain modified basalt fiber.

[0009] Preferably, the mass ratio of the ferric nitrate ethanol solution and basalt fiber in B1 is 100-120:20; The concentration of the ferric nitrate ethanol solution described in B1 is 0.1 mol / L; The total flow rate of the methane and hydrogen mixture described in B1 is 100-200 mL / min, and the volume ratio of methane to hydrogen is 1:4-5. The mass ratio of anhydrous ethanol, deionized water, silane coupling agent KH-550, and pretreated basalt fiber in B2 is 60-100:1-2:0.5:20.

[0010] Preferably, the method for preparing the synergistic microspheres is as follows: C1: Add sodium dodecyl sulfate to deionized water and stir well to obtain a sodium dodecyl sulfate solution; C2: Mix methyl methacrylate and maleic anhydride to obtain the shell monomer; C3: Polycaprolactone diol is dehydrated at 110℃ and -0.09MPa vacuum for 1-1.5h. Then, under a nitrogen atmosphere, the temperature is lowered to 75℃, and isophorone diisocyanate and dibutyltin dilaurate are added and stirred for 3-3.5h. After cooling to 60℃, 2-hydroxyethyl disulfide is added and stirred for 30-40min. Then, at 60℃, a sodium dodecyl sulfate solution at 60℃ is added while stirring at 8000-10000r / min, and the mixture is sonicated for 20-30 minutes. The mixture was then added dropwise at 0.5 g / min to an aqueous solution of ethylenediamine and reacted at 75 °C for 1-2 h. Subsequently, the shell monomer was added dropwise at 0.1-0.3 g / min at 70 °C, while an aqueous solution of potassium persulfate was added dropwise at 0.2-0.4 g / min and stirred at 70 °C for 4-5 h. After cooling to room temperature, the mixture was spray-dried at an inlet air temperature of 120-130 °C and an outlet air temperature of 60-70 °C to obtain synergistic microspheres with an average particle size of approximately 0.5-2.0 μm.

[0011] Preferably, the mass ratio of deionized water to sodium dodecyl sulfate in C1 is 397-402:3; The mass ratio of methyl methacrylate to maleic anhydride in C2 is 10-10.2:1.

[0012] Preferably, the mass ratio of polycaprolactone diol, isophorone diisocyanate, dibutyltin dilaurate, 2-hydroxyethyl disulfide, sodium dodecyl sulfate solution, ethylenediamine aqueous solution, shell monomer, and potassium persulfate aqueous solution in C3 is 50:15:0.03:5:400-405:10:11-11.2:10-12; The mass fraction of the ethylenediamine aqueous solution described in C3 is 5%; The mass fraction of the potassium persulfate aqueous solution described in C3 is 1%.

[0013] A method for preparing a UV-resistant and aging-resistant PE threaded pipe includes the following steps: S1: Add maleic anhydride-grafted polyethylene 1 and polyethylene wax 1 to PE100 resin and mix at 600 r / min for 2-3 min. Then add aluminum hydroxide, magnesium hydroxide, and UV shielding agent and stir at 800-1000 r / min for 8-10 min. Next, add modified basalt fiber, synergistic microspheres, antioxidant 3114, antioxidant 168, and color masterbatch and stir at 800-1000 r / min for 5-7 min. Then add maleic anhydride-grafted polyethylene 2 and polyethylene wax 2 and mix at 1200 r / min for 18-25 min. Then, use a co-rotating parallel twin-screw extruder with an aspect ratio of 25-30:1 to process, cool, and pelletize the mixture at a temperature range of 160-180℃ and a main screw speed of 200-220 r / min to obtain modified PE masterbatch. S2: The modified PE masterbatch is fed into a PE threaded pipe extruder for extrusion, cooling and shaping, and then cut to obtain UV-resistant and aging-resistant PE threaded pipe.

[0014] Preferably, the mass ratio of PE100 resin, maleic anhydride-grafted polyethylene 1, polyethylene wax 1, aluminum hydroxide, magnesium hydroxide, UV shielding agent, modified basalt fiber, synergistic microspheres, antioxidant 3114, antioxidant 168, color masterbatch, maleic anhydride-grafted polyethylene 2, and polyethylene wax 2 in S1 is 100-110:0.5-0.7:0.5-0.7:4-6:4-6:3-5:5-8:4-6:0.3-0.5:0.3-0.5:1-2:1-1.5:0.2-0.8; In the extrusion and cooling shaping process described in S2, the temperature of the feeding section is 150-155℃, the temperature of the compression section is 160-170℃, the temperature of the homogenization section is 170-180℃, the die head temperature is 175-185℃, the die temperature is 180-190℃, the screw length-to-diameter ratio is 20-25:1, the compression ratio is 3:1, the thread vacuum shaping die pressure is -0.06--0.08MPa, the thread forming cooling water temperature is 15-20℃, and the traction speed is 3-5m / min.

[0015] The beneficial effects of this invention are: This invention provides a UV-resistant and aging-resistant PE threaded pipe and its preparation method. The invention effectively improves the impact resistance, low-temperature impact resistance, tensile strength, weather resistance, and aging resistance of the PE threaded pipe through the following methods.

[0016] (1) The nano-titanium dioxide in the UV shielding agent of the present invention has a strong absorption and scattering effect on ultraviolet light in the 340nm band. The core-shell structure of the hollow glass microspheres makes them uniformly dispersed in the PE matrix, forming an ultraviolet blocking network, effectively blocking ultraviolet rays from penetrating the PE molecular chain, reducing photo-oxidative degradation, and greatly improving weather resistance.

[0017] (2) In the modified basalt fiber of this invention, the basalt fiber can bridge the cracks on both sides after the material is subjected to impact and develops notch cracks, preventing the cracks from spreading rapidly. At the same time, the fiber can absorb some of the impact energy through its own small deformation, reducing material fracture caused by energy concentration. The modification of the silane coupling agent KH-550 can make the organic groups on the fiber surface compatible with the PE matrix, avoiding the fiber from debonding during impact. The strong interfacial bonding can transfer the impact energy to the fiber more efficiently, further improving the energy dissipation efficiency and increasing the notch impact strength. The modification of the silane coupling agent KH-550 greatly improves the interfacial bonding force, enabling the pipe to resist the interfacial stress caused by low temperature shrinkage, reducing the risk of fiber and matrix debonding, and avoiding a sharp drop in impact performance due to debonding. The carbon coating formed on the fiber surface by the methane and hydrogen mixed gas has a certain degree of flexibility and can buffer stress through small deformation at low temperature. At the same time, the rigid skeleton of the basalt fiber itself can support the embrittled PE matrix, preventing the crack from penetrating rapidly due to the lack of toughness of the matrix, thereby improving the notch impact strength at low temperature. The silane coupling agent KH-550 modification eliminates the interfacial barrier between the fiber and the matrix, enabling stress to be efficiently transferred from the PE matrix to the fiber during tension, allowing the fiber to bear more tensile load and improving tensile strength. Modified basalt fiber can improve the density of the material structure, reducing UV-induced matrix cracking and degradation channels; simultaneously, it synergizes with the UV shielding agent in the system to further delay UV damage to the PE molecular chain. Modified basalt fiber can form a physical barrier in the PE matrix, reducing oxygen penetration into the material; simultaneously, it synergizes with antioxidants 3114 and 168 to further inhibit free radical chain reactions caused by thermo-oxidative aging; furthermore, the high-temperature stability of the fiber ensures that the reinforcing structure does not fail during thermo-oxidative aging, effectively improving long-term thermal stability.

[0018] (3) The core layer of the enhanced microspheres of this invention is a flexible chain segment, and the shell layer is a rigid structure. When the material is impacted, the core layer can absorb the impact energy through plastic deformation, and the shell layer can avoid stress concentration through stress transfer and dispersion. The two work together to effectively improve the impact resistance. The core layer of the enhanced microspheres can still maintain flexibility in low-temperature environments such as -20℃. During low-temperature impact, the mobility of the chain segments in the core layer can effectively buffer the stress and prevent the material from breaking due to freezing of molecular chains, thus effectively improving the notched impact strength at low temperatures. The carboxyl groups of maleic anhydride in the shell layer can undergo esterification with maleic anhydride-grafted polyethylene in the PE system to form a strong interfacial bond, preventing the microspheres from debonding from the PE matrix. The rigid chain segments of methyl methacrylate in the shell layer can provide physical support. The two work together to effectively improve the tensile strength. The enhanced microspheres can act as a dispersion medium to make the UV shielding agent more evenly distributed in the PE matrix, reduce the UV shielding blind zone caused by agglomeration, and improve the weather resistance of the material. The core polyurethane structure and the shell maleic anhydride have good thermal stability, which can delay the thermal and oxidative degradation of PE molecular chains; they can also form a synergistic antioxidant network with antioxidants 3114 and 168 in the system, further improving aging resistance.

[0019] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. The embodiments described below are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Unless otherwise specified, the following information pertains to some of the raw materials used in the following embodiments and comparative examples of this invention: Nano-titanium dioxide, with a particle size of 20nm, was purchased from Shanghai Mairui Biochemical Technology Co., Ltd.; basalt fiber with a diameter of 20μm was purchased from Guangdong Zhongtian Gangqiao Construction Engineering Co., Ltd.; hollow glass microspheres were purchased from Shanghai Saikerui Biotechnology Co., Ltd., item number: SRCP-HGMS-0.835-15um-0.5g; polycaprolactone diol was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., item number: P303566; PE100 resin was purchased from Dongguan Minghui Plastics Co., Ltd., item number: 4197681; maleic anhydride grafted polyethylene was purchased from Dongguan Shenghao Plastic Raw Materials Co., Ltd., item number: 5541254; polyethylene wax was purchased from Hubei Yongkuo Technology Co., Ltd., item number: YK3401; color masterbatch was purchased from Shanghai Shiqin New Material Technology Co., Ltd., grade: PE6269B.

[0022] Example 1: A method for preparing a UV-resistant and aging-resistant PE threaded pipe is as follows: S1: Add 20g of basalt fiber to 100g of 0.1mol / L ferric nitrate ethanol solution and stir for 30min. Then centrifuge and dry the precipitate at 80℃ for 2h. Then heat to 350℃ at 5℃ / min and hold for 1h. Then heat to 650℃ under nitrogen atmosphere and hold for 30min. Then introduce a mixture of methane and hydrogen gas with a total flow rate of 100mL / min and a volume ratio of 1:4. After 4h, cool to room temperature under nitrogen atmosphere to obtain pretreated basalt fiber. S2: Add 1g of deionized water and 0.5g of silane coupling agent KH-550 to 60g of anhydrous ethanol and stir for 10min. Then adjust the pH to 4 with acetic acid, add 20g of pretreated basalt fiber and ultrasonically disperse for 30min. Stir at 58℃ for 2h, centrifuge and then vacuum dry at 80℃ and -0.09MPa for 4h to obtain modified basalt fiber. S3: Add 30g of deionized water and 5g of silane coupling agent KH-550 to 500g of anhydrous ethanol and stir for 10min. Then adjust the pH to 4 with acetic acid, add 100g of nano titanium dioxide and ultrasonically disperse for 30min. Stir at 58℃ for 2h to obtain a pretreated titanium dioxide suspension. S4: Add 150g of hollow glass microspheres to 800g of deionized water and adjust the pH to 4 with acetic acid. Then, while stirring at 800r / min, add 250g of pretreated titanium dioxide suspension dropwise at 10g / min. Adjust the pH to 8.5 with ammonia water and stir at 65℃ for 4h. After cooling to room temperature, filter and wash the precipitate 4 times alternately with deionized water and anhydrous ethanol. After vacuum drying at 80℃ and -0.095MPa for 8h, pulverize and pass through an 800-mesh sieve to obtain the ultraviolet shielding agent. S5: Add 3g of sodium dodecyl sulfate to 397g of deionized water and stir until homogeneous to obtain a sodium dodecyl sulfate solution; S6: Mix 10g of methyl methacrylate and 1g of maleic anhydride evenly to obtain the shell monomer; S7: Dehydrate 50g of polycaprolactone diol at 110℃ and -0.09MPa vacuum for 1h, then cool to 75℃ under a nitrogen atmosphere and add 15g of isophorone diisocyanate and 0.03g of dibutyltin dilaurate, stirring for 3h. After cooling to 60℃, add 5g of... 2-Hydroxyethyl disulfide was stirred for 30 min, and then 400 g of sodium dodecyl sulfate solution at 60 °C was added while stirring at 8000 r / min and sonicated for 20 min. Then, 10 g of 5% ethylenediamine aqueous solution was added dropwise at 0.5 g / min and reacted at 75 °C for 1 h. Subsequently, 11 g of shell monomer was added dropwise at 0.1 g / min at 70 °C, and 10 g of 1% potassium persulfate aqueous solution was added dropwise at 0.2 g / min and stirred at 70 °C for 4 h. After cooling to room temperature, spray drying was performed at an inlet air temperature of 120 °C and an outlet air temperature of 60 °C to obtain synergistic microspheres with an average particle size of approximately 0.5-2.0 μm. S8: Add 0.5g of maleic anhydride-grafted polyethylene and 0.5g of polyethylene wax to 100g of PE100 resin and mix at 600r / min for 2min. Then add 4g of aluminum hydroxide, 4g of magnesium hydroxide, and 3g of UV shielding agent and stir at 800r / min for 8min. Next, add 5g of modified basalt fiber, 4g of enhanced microspheres, 0.3g of antioxidant 3114, 0.3g of antioxidant 168, and 1g of color masterbatch and stir at 800r / min for 5min. Then add 1g of maleic anhydride-grafted polyethylene and 0.2g of polyethylene wax and mix at 1200r / min for 18min. Then process, cool, and pelletize using a co-rotating parallel twin-screw extruder with a length-to-diameter ratio of 25:1 at a temperature range of 160℃ and a main screw speed of 200r / min to obtain modified PE masterbatch. S9: Modified PE masterbatch is fed into a PE threaded pipe extruder for extrusion and cooling treatment at the following temperatures: feeding section temperature 150℃, compression section temperature 160℃, homogenization section temperature 170℃, die head temperature 175℃, die temperature 180℃, screw length-to-diameter ratio 20:1, compression ratio 3:1, thread vacuum forming die pressure -0.06MPa, thread forming cooling water temperature 15℃, and traction speed 3m / min. After cutting, UV-resistant and aging-resistant PE threaded pipe is obtained.

[0023] Example 2: A method for preparing a UV-resistant and aging-resistant PE threaded pipe is as follows: S1: Add 20g of basalt fiber to 110g of 0.1mol / L ferric nitrate ethanol solution and stir for 40min. Then centrifuge and dry the precipitate at 90℃ for 2.5h. Then heat to 350℃ at 5℃ / min and hold for 1.1h. Then heat to 650℃ under nitrogen atmosphere and hold for 35min. Then introduce a methane and hydrogen mixed gas with a total flow rate of 150mL / min and a volume ratio of 1:4.5. After 5h, cool to room temperature under nitrogen atmosphere to obtain pretreated basalt fiber. S2: Add 1.5g deionized water and 0.5g silane coupling agent KH-550 to 80g anhydrous ethanol and stir for 15min. Then adjust the pH to 4.5 with acetic acid, add 20g pretreated basalt fiber and ultrasonically disperse for 40min. Stir at 59℃ for 2.5h, centrifuge and vacuum dry at 80℃ and -0.09MPa for 5h to obtain modified basalt fiber. S3: Add 40g of deionized water and 5g of silane coupling agent KH-550 to 500g of anhydrous ethanol and stir for 15min. Then adjust the pH to 4.5 with acetic acid, add 100g of nano titanium dioxide and ultrasonically disperse for 40min. Then stir at 59℃ for 2.5h to obtain a pretreated titanium dioxide suspension. S4: Add 150g of hollow glass microspheres to 800g of deionized water and adjust the pH to 4 with acetic acid. Then, while stirring at 900r / min, add 300g of pretreated titanium dioxide suspension dropwise at 10g / min. Adjust the pH to 8.5 with ammonia water and stir at 65℃ for 4.5h. After cooling to room temperature, filter and wash the precipitate 4 times alternately with deionized water and anhydrous ethanol. After vacuum drying at 80℃ and -0.095MPa for 8.5h, pulverize and pass through an 800-mesh sieve to obtain the ultraviolet shielding agent. S5: Add 3g of sodium dodecyl sulfate to 400g of deionized water and stir until homogeneous to obtain a sodium dodecyl sulfate solution; S6: Mix 10.1g of methyl methacrylate and 1g of maleic anhydride evenly to obtain the shell monomer; S7: Dehydrate 50g of polycaprolactone diol at 110℃ and -0.09MPa vacuum for 1-1.5h, then cool to 75℃ under a nitrogen atmosphere and add 15g of isophorone diisocyanate and 0.03g of dibutyltin dilaurate, stirring for 3.2h. After cooling to 60℃, add 5g of... 2-Hydroxyethyl disulfide was stirred for 35 min, and then 403 g of sodium dodecyl sulfate solution at 60 °C was added while stirring at 9000 r / min and sonicated for 25 min. Then, 10 g of 5% ethylenediamine aqueous solution was added dropwise at 0.5 g / min and reacted at 75 °C for 1.5 h. Subsequently, 11.1 g of shell monomer was added dropwise at 0.2 g / min at 70 °C, and 11 g of 1% potassium persulfate aqueous solution was added dropwise at 0.3 g / min and stirred at 70 °C for 4.5 h. After cooling to room temperature, spray drying was carried out at an inlet air temperature of 125 °C and an outlet air temperature of 65 °C to obtain synergistic microspheres with an average particle size of approximately 0.5-2.0 μm. S8: Add 0.6g of maleic anhydride-grafted polyethylene and 0.6g of polyethylene wax to 105g of PE100 resin and mix at 600r / min for 2.5min. Then add 5g of aluminum hydroxide, 5g of magnesium hydroxide, and 4g of UV shielding agent and stir at 900r / min for 9min. Next, add 6.5g of modified basalt fiber, 5g of enhanced microspheres, 0.4g of antioxidant 3114, 0.4g of antioxidant 168, and 1.5g of color masterbatch and stir at 900r / min for 6min. Then add 1.2g of maleic anhydride-grafted polyethylene and 0.5g of polyethylene wax and mix at 1200r / min for 22min. Then process, cool, and pelletize using a co-rotating parallel twin-screw extruder with a length-to-diameter ratio of 28:1 at a temperature range of 170℃ and a main screw speed of 210r / min to obtain modified PE masterbatch. S9: Modified PE masterbatch is fed into a PE threaded pipe extruder for extrusion and cooling treatment at the following temperatures: feeding section temperature 153℃, compression section temperature 165℃, homogenization section temperature 175℃, die head temperature 180℃, die temperature 185℃, screw length-to-diameter ratio 23:1, compression ratio 3:1, thread vacuum forming die pressure -0.07MPa, thread forming cooling water temperature 18℃, and traction speed 4m / min. After cutting, UV-resistant and aging-resistant PE threaded pipe is obtained.

[0024] Example 3: A method for preparing a UV-resistant and aging-resistant PE threaded pipe is as follows: S1: Add 20g of basalt fiber to 120g of 0.1mol / L ferric nitrate ethanol solution and stir for 50min. Then centrifuge and dry the precipitate at 100℃ for 3h. Then heat to 350℃ at 5℃ / min and hold for 1.2h. Then heat to 650℃ under nitrogen atmosphere and hold for 40min. Then introduce a methane and hydrogen mixed gas with a total flow rate of 200mL / min and a volume ratio of 1:5. After 6h, cool to room temperature under nitrogen atmosphere to obtain pretreated basalt fiber. S2: Add 2g of deionized water and 0.5g of silane coupling agent KH-550 to 100g of anhydrous ethanol and stir for 20min. Then adjust the pH to 5 with acetic acid, add 20g of pretreated basalt fiber and ultrasonically disperse for 50min. Stir at 60℃ for 3h, centrifuge and then vacuum dry at 80℃ and -0.09MPa for 6h to obtain modified basalt fiber. S3: Add 50g of deionized water and 5g of silane coupling agent KH-550 to 500g of anhydrous ethanol and stir for 20min. Then adjust the pH to 5 with acetic acid, add 100g of nano titanium dioxide and ultrasonically disperse for 50min. Then stir at 60℃ for 3h to obtain a pretreated titanium dioxide suspension. S4: Add 150g of hollow glass microspheres to 800g of deionized water and adjust the pH to 4 with acetic acid. Then, while stirring at 1000r / min, add 350g of pretreated titanium dioxide suspension dropwise at 10g / min. Adjust the pH to 8.5 with ammonia water and stir at 65℃ for 5h. After cooling to room temperature, filter and wash the precipitate 4 times alternately with deionized water and anhydrous ethanol. After vacuum drying at 80℃ and -0.095MPa for 9h, pulverize and pass through an 800-mesh sieve to obtain the ultraviolet shielding agent. S5: Add 3g of sodium dodecyl sulfate to 402g of deionized water and stir until homogeneous to obtain a sodium dodecyl sulfate solution; S6: Mix 10.2g of methyl methacrylate and 1g of maleic anhydride evenly to obtain the shell monomer; S7: Dehydrate 50g of polycaprolactone diol at 110℃ and -0.09MPa vacuum for 1.5h, then cool to 75℃ under a nitrogen atmosphere and add 15g of isophorone diisocyanate and 0.03g of dibutyltin dilaurate, stirring for 3.5h. After cooling to 60℃, add 5g of... 2-Hydroxyethyl disulfide was stirred for 40 min, then 405 g of sodium dodecyl sulfate solution at 60 °C was added while stirring at 10000 r / min and sonicated for 30 min. Then 10 g of 5% ethylenediamine aqueous solution was added dropwise at 0.5 g / min and reacted at 75 °C for 2 h. Subsequently, 11.2 g of shell monomer was added dropwise at 0.3 g / min at 70 °C, and 12 g of 1% potassium persulfate aqueous solution was added dropwise at 0.4 g / min and stirred at 70 °C for 5 h. After cooling to room temperature, spray drying was performed at an inlet air temperature of 130 °C and an outlet air temperature of 70 °C to obtain synergistic microspheres with an average particle size of approximately 0.5-2.0 μm. S8: Add 0.7g maleic anhydride-grafted polyethylene and 0.7g polyethylene wax to 110g of PE100 resin and mix at 600r / min for 3min. Then add 6g aluminum hydroxide, 6g magnesium hydroxide, and 5g UV shielding agent and stir at 1000r / min for 10min. Next, add 8g modified basalt fiber, 6g enhanced microspheres, 0.5g antioxidant 3114, 0.5g antioxidant 168, and 2g color masterbatch and stir at 1000r / min for 7min. Then add 1.5g maleic anhydride-grafted polyethylene and 0.8g polyethylene wax and mix at 1200r / min for 25min. Then process, cool, and pelletize using a co-rotating parallel twin-screw extruder with a length-to-diameter ratio of 30:1 at a temperature range of 180℃ and a main screw speed of 220r / min to obtain modified PE masterbatch. S9: Modified PE masterbatch is fed into a PE threaded pipe extruder for extrusion and cooling treatment at the following temperatures: feeding section temperature 155℃, compression section temperature 170℃, homogenization section temperature 180℃, die head temperature 185℃, die temperature 190℃, screw length-to-diameter ratio 25:1, compression ratio 3:1, thread vacuum forming die pressure -0.08MPa, thread forming cooling water temperature 20℃, and traction speed 5m / min. After cutting, UV-resistant and aging-resistant PE threaded pipe is obtained.

[0025] Comparative Example 1: Compared with Example 1, this comparative example only did not add "ultraviolet shielding agent" in the preparation process of S8. All other steps and parameters were the same, and will not be repeated here. The final product is an ultraviolet-resistant and aging-resistant PE threaded pipe.

[0026] Comparative Example 2: Compared with Example 1, this comparative example only did not add "modified basalt fiber" in the preparation process of S8. All other steps and parameters were the same, and will not be repeated here. The final product is a UV-resistant and aging-resistant PE threaded pipe.

[0027] Comparative Example 3: Compared with Example 1, this comparative example only did not add "enhancing microspheres" in the preparation process of S8. All other steps and parameters were the same, and will not be repeated here. The final product is a UV-resistant and aging-resistant PE threaded pipe.

[0028] Performance testing: Impact strength determination: Referring to GB / T 1043.1-2008 standard, the UV-resistant and aging-resistant PE threaded pipes prepared in Examples 1-3 and Comparative Examples 1-2 of this invention were tested. After preparing samples with dimensions of 80mm × 10mm × 4mm and a Type A notch depth of 2mm, the notched impact strength (kJ·m) at 23℃ and -20℃ was measured. -2 The test results are shown in Table 1.

[0029] Determination of tensile strength: Referring to GB / T 8804.2-2003 standard, the tensile strength (MPa) of the UV-resistant and aging-resistant PE threaded pipes prepared in Examples 1-3 and Comparative Examples 1-2 of this invention was measured at a tensile speed of 50 mm / min at 23℃ and 50% RH. The test results are shown in Table 1.

[0030] Weather resistance testing: Referring to GB / T 16422.2-2022 standard, the UV-resistant and aging-resistant PE threaded pipes prepared in Examples 1-3 and Comparative Examples 1-2 of this invention were tested. After preparing samples with dimensions of 150mm × 70mm × 4mm, they were subjected to irradiation at 340nm at a concentration of 0.55W / m². 2 The impact strength retention rate (%) after treatment with ·nm, blackboard temperature of 65℃ and relative humidity of 50% for 1000h (a cycle of 102min light exposure + 18min water spray) is shown in Table 1.

[0031] Determination of aging resistance: Referring to GB / T 2951.42-2008 standard, the tensile strength retention rate (%) of the UV-resistant and aging-resistant PE threaded pipes prepared in Examples 1-3 and Comparative Examples 1-2 of this invention was determined after aging at 110℃ for 240h with samples of size 150mm×70mm×4mm. The test results are shown in Table 1.

[0032] Table 1: Basic performance test results of Examples 1-3 and Comparative Examples 1-3

[0033] Data Analysis: As can be seen from Table 1, the UV-resistant and aging-resistant PE threaded pipe prepared in the embodiments of the present invention has excellent impact resistance, low-temperature impact resistance, tensile strength, weather resistance, and aging resistance.

[0034] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0035] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A UV-resistant and aging-resistant PE threaded pipe, characterized in that, The raw materials include the following parts by weight: 100-110 parts of PE100 resin, 1.5-2.2 parts of maleic anhydride grafted polyethylene, 0.7-1.5 parts of polyethylene wax, 4-6 parts of aluminum hydroxide, 4-6 parts of magnesium hydroxide, 3-5 parts of UV shielding agent, 5-8 parts of modified basalt fiber, 4-6 parts of synergistic microspheres, 0.3-0.5 parts of antioxidant 3114, 0.3-0.5 parts of antioxidant 168, and 1-2 parts of color masterbatch; The ultraviolet shielding agent is made from KH-550 modified nano-titanium dioxide and hollow glass microspheres; The modified basalt fiber is a basalt fiber that has undergone carbon deposition and then been modified with silane coupling agent KH-550. The enhanced microspheres are composite microspheres with polycaprolactone, isophorone diisocyanate and 2-hydroxyethyl disulfide polyurethane prepolymer extended by ethylenediamine as the core and methyl methacrylate and maleic anhydride copolymer as the shell. The method for preparing the ultraviolet shielding agent is as follows: A1: Add deionized water and silane coupling agent KH-550 to anhydrous ethanol and stir well. Then adjust the pH to 4-5, add nano titanium dioxide and sonicate for 30-50 min. Stir at 58-60℃ for 2-3 h to obtain a pretreated titanium dioxide suspension. A2: Add hollow glass microspheres to deionized water and adjust the pH to 4. Then, while stirring, drop in the pretreated titanium dioxide suspension. Adjust the pH to 8.5 and stir at 65°C for 4-5 hours. After cooling, filter, wash the precipitate, vacuum dry, pulverize, and sieve to obtain the ultraviolet shielding agent. The modified basalt fiber is prepared as follows: B1: Basalt fiber is added to ferric nitrate ethanol solution and stirred for 30-50 min. Then it is centrifuged and dried, then kept at 350℃ for 1-1.2 h, and then kept at 650℃ under nitrogen atmosphere for 30-40 min. Then a mixture of methane and hydrogen gas is introduced, and after 4-6 h it is cooled under nitrogen atmosphere to obtain pretreated basalt fiber. B2: Add deionized water and silane coupling agent KH-550 to anhydrous ethanol and stir well. Then adjust the pH to 4-5, add pretreated basalt fiber and sonicate for 30-50 min. Stir at 58-60℃ for 2-3 h, centrifuge and vacuum dry to obtain modified basalt fiber. The method for preparing the synergistic microspheres is as follows: C1: Add sodium dodecyl sulfate to deionized water and stir well to obtain a sodium dodecyl sulfate solution; C2: Mix methyl methacrylate and maleic anhydride to obtain the shell monomer; C3: Polycaprolactone diol was dehydrated under vacuum, and isophorone diisocyanate and dibutyltin dilaurate were added under a nitrogen atmosphere at 75°C and stirred for 3-3.5 h. After cooling to 60°C, 2-hydroxyethyl disulfide was added and stirred for 30-40 min. Then sodium dodecyl sulfate solution was added and sonicated for 20-30 min. Then ethylenediamine aqueous solution was added dropwise and reacted at 75°C for 1-2 h. Subsequently, shell monomer and potassium persulfate aqueous solution were added dropwise at 70°C and stirred for 4-5 h. After cooling, spray drying was performed to obtain synergistic microspheres.

2. The UV-resistant and aging-resistant PE threaded pipe according to claim 1, characterized in that, The mass ratio of anhydrous ethanol, deionized water, silane coupling agent KH-550, and nano titanium dioxide in A1 is 500:30-50:5:

100. The mass ratio of deionized water, hollow glass microspheres, and pretreated titanium dioxide suspension in A2 is 800:150:250-350.

3. The UV-resistant and aging-resistant PE threaded pipe according to claim 1, characterized in that, The mass ratio of the ferric nitrate ethanol solution and basalt fiber in B1 is 100-120:20; The concentration of the ferric nitrate ethanol solution described in B1 is 0.1 mol / L; The total flow rate of the methane and hydrogen mixture described in B1 is 100-200 mL / min, and the volume ratio of methane to hydrogen is 1:4-5. The mass ratio of anhydrous ethanol, deionized water, silane coupling agent KH-550, and pretreated basalt fiber in B2 is 60-100:1-2:0.5:

20.

4. The UV-resistant and aging-resistant PE threaded pipe according to claim 1, characterized in that, The mass ratio of deionized water to sodium dodecyl sulfate in C1 is 397-402:3; The mass ratio of methyl methacrylate to maleic anhydride in C2 is 10-10.2:

1.

5. The UV-resistant and aging-resistant PE threaded pipe according to claim 1, characterized in that, The mass ratio of polycaprolactone diol, isophorone diisocyanate, dibutyltin dilaurate, 2-hydroxyethyl disulfide, sodium dodecyl sulfate solution, ethylenediamine aqueous solution, shell monomer, and potassium persulfate aqueous solution in C3 is 50:15:0.03:5:400-405:10:11-11.2:10-12; The mass fraction of the ethylenediamine aqueous solution described in C3 is 5%; The mass fraction of the potassium persulfate aqueous solution described in C3 is 1%.

6. A method for preparing a UV-resistant and aging-resistant PE threaded pipe according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Add maleic anhydride-grafted polyethylene 1 and polyethylene wax 1 to PE100 resin and mix for 2-3 minutes. Then add aluminum hydroxide, magnesium hydroxide, and UV shielding agent and stir for 8-10 minutes. Next, add modified basalt fiber, synergistic microspheres, antioxidant 3114, antioxidant 168, and color masterbatch and stir for 5-7 minutes. Then add maleic anhydride-grafted polyethylene 2 and polyethylene wax 2 and mix for 18-25 minutes. Finally, extrude, cool, and pelletize using a co-rotating parallel twin-screw extruder to obtain modified PE masterbatch. S2: The modified PE masterbatch is fed into a PE threaded pipe extruder for extrusion, cooling and shaping, and then cut to obtain UV-resistant and aging-resistant PE threaded pipe.

7. The method for preparing the UV-resistant and aging-resistant PE threaded pipe according to claim 6, characterized in that, The mass ratio of PE100 resin, maleic anhydride-grafted polyethylene 1, polyethylene wax 1, aluminum hydroxide, magnesium hydroxide, UV shielding agent, modified basalt fiber, synergistic microspheres, antioxidant 3114, antioxidant 168, color masterbatch, maleic anhydride-grafted polyethylene 2, and polyethylene wax 2 in S1 is 100-110:0.5-0.7:0.5-0.7:4-6:4-6:3-5:5-8:4-6:0.3-0.5:0.3-0.5:1-2:1-1.5:0.2-0.8; In the extrusion and cooling shaping process described in S2, the temperature of the feeding section is 150-155℃, the temperature of the compression section is 160-170℃, the temperature of the homogenization section is 170-180℃, the die head temperature is 175-185℃, the die temperature is 180-190℃, the screw length-to-diameter ratio is 20-25:1, the compression ratio is 3:1, the thread vacuum shaping die pressure is -0.06--0.08MPa, the thread forming cooling water temperature is 15-20℃, and the traction speed is 3-5m / min.

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