Impact-resistant HDPE corrugated pipe and preparation method thereof

Abstract

The present invention discloses an impact-resistant HDPE corrugated pipe and a method for preparing the same, belonging to the technical field of corrugated pipe preparation. The impact-resistant HDPE corrugated pipe is composed of the following components by weight: 70-80 parts high-density polyethylene, 5-9 parts polypropylene, 5-9 parts elastic additive, 2-5 parts adhesive resin, 1-4 parts composite additive, 1-2 parts ultraviolet absorber, and 1-2 parts antioxidant. The resulting HDPE corrugated pipe exhibits excellent impact resistance, low-temperature resistance, and corrosion resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of corrugated pipe preparation, and particularly relates to an impact-resistant HDPE corrugated pipe and a preparation method thereof. Background Art

[0002] As an important piping material, HDPE corrugated pipe is widely used in municipal projects such as drainage, gas, and water supply, as well as in agricultural irrigation and communication pipelines. However, with the continuous development of infrastructure construction and the increasing complexity of application scenarios, the performance requirements for HDPE corrugated pipe are also becoming increasingly higher. Traditional HDPE corrugated pipes are prone to deformation or damage when subjected to external impact, which seriously affects their service life and safety. This is especially true in areas with complex geological conditions and harsh construction environments. HDPE corrugated pipes need to withstand greater external impacts, and the impact resistance of traditional materials often cannot meet actual needs. Therefore, there is an urgent need to improve the impact resistance of HDPE corrugated pipes.

[0003] Patent CN111087669A discloses a method for preparing impact-resistant and high-toughness corrugated pipes. The invention adds modified fossil powder to the raw materials for corrugated pipe preparation, and produces impact-resistant and high-toughness corrugated pipes through extrusion granulation and sizing, pulling, cooling and shaping. Talc is used as raw material and mixed with sodium silicate solution. Under the action of hydrochloric acid, sodium silicate and hydrochloric acid react to fix nano-silicon dioxide particles on the surface, thereby increasing the specific surface area of talc. The high specific surface area of talc adsorbs esterification products, thereby improving the compatibility between the modified talc and the polyethylene matrix. When the corrugated pipe material is subjected to external force, relative slippage is easily generated between the layers, thereby improving the toughness of the corrugated plate. A large amount of nano-scale silica is deposited on the surface of the modified talc, thereby improving the impact resistance of the corrugated plate. However, the impact resistance, high temperature resistance and corrosion resistance of the corrugated pipe prepared by this method still have room for improvement. Summary of the Invention

[0004] The purpose of the present invention is to provide an impact-resistant HDPE corrugated pipe and a preparation method thereof, so as to solve the technical problems of poor impact resistance, high temperature resistance and corrosion resistance of the corrugated pipe in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The invention provides an impact-resistant HDPE corrugated pipe, which is composed of the following components in parts by weight: 70-80 parts of high-density polyethylene, 5-9 parts of polypropylene, 5-9 parts of elastic additives, 2-5 parts of adhesive resin, 1-4 parts of composite auxiliary agent, 1-2 parts of ultraviolet absorber, and 1-2 parts of antioxidant.

[0007] Preferably, the preparation method of the elastic additive comprises the following steps:

[0008] Q1: Under argon protection, 2-amino-4-hydroxy-6-methylpyrimidine was added to a container, followed by hexamethylene diisocyanate and pyridine. The mixture was heated, condensed, refluxed, and stirred for reaction. After the reaction was completed, n-pentane was added, the mixture was filtered, washed, and dried to obtain intermediate 1.

[0009] Q2: Add 2-amino-2-methyl-1,3-propanediol to a container, then add intermediate 1, and then add chloroform. Under nitrogen protection, heat in an oil bath to react. After the reaction is completed, cool, filter, dissolve, centrifuge, precipitate, filter, wash, and dry to obtain intermediate 2;

[0010] In the above process, the synthetic reaction formula of intermediate 2 is as follows:

[0011]

[0012] Q3: Add oleic acid, trimethylolpropane, phthalic anhydride and neopentyl glycol to a container, then add xylene and hypophosphorous acid, heat the reaction, continue to heat the reaction, cool, rotary evaporate and dry to obtain intermediate 3;

[0013] In the above process, the synthetic reaction formula of intermediate 3 is as follows:

[0014]

[0015] Q4: Add intermediate 3 and isophorone diisocyanate to a container, then add N,N-dimethylformamide, and heat the reaction under nitrogen protection. After stirring evenly, add dibutyltin dilaurate and continue the reaction. Then add intermediate 2, heat the reaction and continue the reaction. After the reaction is completed, rotary evaporate and dry to obtain an elastic additive.

[0016] Preferably, in Q1, the amount ratio of 2-amino-4-hydroxy-6-methylpyrimidine, hexamethylene diisocyanate, pyridine and n-pentane is (5-7.5) g: (50-75) mL: (4-6) mL: (15-20) mL, the heating, condensing, reflux and stirring reaction temperature is 95-105°C, the reaction time is 10-12 h, and the reaction is washed with acetone; in Q2, the amount ratio of 2-amino-2-methyl-1,3-propanediol, intermediate 1 and chloroform is (15-19.34) g: (30-33.4) g: (170-190) mL, the oil bath heating reaction temperature is 55-65°C, and the reaction time is 10-14 h.

[0017] Preferably, in Q3, the amount ratio of oleic acid, trimethylolpropane, phthalic anhydride, neopentyl glycol, xylene and hypophosphorous acid is (200-216.2) g: (91.2-96.4) g: (85-89.9) g: (10-14.3) g: (30-34.6) g: (0.6-1.1) g, the reaction temperature is 150-155 ° C, the reaction time is 30-45 min, and the reaction temperature is continued to rise to 220-230 ° C, the reaction time is The reaction time is 4-7h; in Q4, the usage ratio of intermediate 3, isophorone diisocyanate, N,N-dimethylformamide, dibutyltin dilaurate and intermediate 2 is (8-12) g: (1.45-1.83) g: (30-40) mL: (0.01-0.014) mL: (0.85-1.02) g, the heating reaction temperature is 60-65°C, the reaction time is 4-5h, and the heating reaction temperature is continued to 70-75°C, and the reaction time is 1-2h.

[0018] Preferably, the preparation method of the composite auxiliary agent comprises the following steps:

[0019] S1: 9-thioxanthone and N-bromosuccinimide are added to a container containing dichloromethane, followed by dropwise addition of methanesulfonic acid, and the mixture is stirred at room temperature for reaction. After the reaction is completed, sodium sulfite is added, extracted, the organic phases are combined, washed, dried, distilled under reduced pressure, and recrystallized to obtain product A. Under an argon atmosphere, diphenyl ether is added to tetrahydrofuran, and a n-hexane solution of n-butyl lithium is added at low temperature. After the dropwise addition is completed, the mixture is reacted at low temperature and then at room temperature. The mixture is then added to a tetrahydrofuran solution containing product A and reacted. After the reaction is completed, saturated ammonium chloride is added, extracted, vacuum distilled, dissolved, refluxed, cooled, diluted, washed, decompressed, and purified to obtain product B.

[0020] S2: Add product B, acetamide, tris(dibenzylideneacetone)dipalladium, 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene, and cesium carbonate to a container. Under argon protection, add 1,4-dioxane, stir to dissolve, heat under reflux to react, and after the reaction is completed, cool, dilute, wash, reduce pressure, and recrystallize to obtain product C;

[0021] S3: adding product C to a mixed solution of methanol and hydrochloric acid, heating for reaction, adjusting the pH, filtering, and recrystallizing to obtain product D;

[0022] S4: Add product D, 4,4'-(hexafluoroisopropylene) diphthalic anhydride, isoquinoline and m-cresol into a container, heat and stir under argon protection, then continue heating and stirring. After the stirring is completed, precipitate, filter, dissolve, purify, and vacuum dry to obtain a composite auxiliary agent.

[0023] In the above process, the synthetic reaction formula of the composite additive is as follows:

[0024]

[0025] The results of mass spectrometry analysis of product A were: m / z: 369.85 (100.0%), 367.85 (50.2%), 371.85(47.8%), 370.85 (14.9%), 372.85 (7.7%), 368.85 (7.5%), 371.84 (4.4%), 373.84(2.2%); the results of mass spectrometry analysis of product B were: m / z: 521.91 (100.0%), 523.91 (52.2%), 519.91(50.2%), 522.91 (27.8%), 524.91 (14.5%), 520.92 (13.7%), 523.92 (3.8%),525.90 (2.1%), The results of mass spectrometry analysis of product C were: m / z: 478.14 (100.0%), 479.14 (31.7%), 480.14 (6.0%), 480.13 (4.5%), 479.13 (1.5%), 481.13 (1.5%); the results of mass spectrometry analysis of product D were: m / z: 394.11 (100.0%), 395.12 (27.3%), 396.11 (4.7%), 396.12 (4.0%), 395.11 (1.5%), 397.11 (1.3%).

[0026] Preferably, in S1, the amount ratio of 9-thioxanthone, N-bromosuccinimide, dichloromethane and methanesulfonic acid is (5-7.2) g: (9.12-9.48) g: (100-120) mL: (3.12-3.54) mL, and the stirring reaction time is 10-12 h; the amount ratio of diphenyl ether, n-hexane solution and product A is (1.72-1.98) mL: (4.12-4.65) mL: (2-2.2) g, the concentration of n-butyl lithium in n-hexane solution is 2.5 mol / L, the low temperature environment temperature is -78~-80°C, the low temperature reaction time is 1-2 h, the room temperature reaction time is 2-4 h, and the reaction time is 10-12 h.

[0027] Preferably, in S2, the amount ratio of product B, acetamide, tris(dibenzylideneacetone)dipalladium, 4,5-bisdiphenylphosphine-9,9-dimethylxanthene, cesium carbonate and 1,4-dioxane is (2-2.5) g: (0.45-0.49) g: (0.18-0.25) g: (0.32-0.45) g: (3.54-3.95) g: (35-42) mL, the heating reflux reaction temperature is 100-110°C, and the reaction time is 8-10 h; in S3, the amount ratio of product C, methanol and hydrochloric acid is (1.25-1.73) g: (8-12) mL: (5-8) mL, the heating reaction temperature is 55-60°C, the reaction time is 3-5 h, and the pH is adjusted to 10-10.2.

[0028] Preferably, in S4, the amount ratio of product D, 4,4'-(hexafluoroisopropylene) diphthalic anhydride, isoquinoline and m-cresol is (0.45-0.55) g: (0.51-0.62) g: (0.11-0.16) mL: (4.8-5.4) mL, the heating and stirring temperature is 80-85 ° C, the stirring time is 4-6 h, and the heating and stirring temperature is continued to be 185-192 ° C, and the stirring time is 10-14 h.

[0029] Preferably, the method for preparing an impact-resistant HDPE corrugated pipe comprises the following steps:

[0030] Step 1: Add high-density polyethylene, polypropylene, elastic additives, adhesive resin, composite additives, ultraviolet absorber and antioxidant into a high-speed mixer, mix well, and obtain a mixture;

[0031] Step 2: Add the mixed material into a twin-screw extruder, melt, mix and plasticize to obtain a uniform melt, extrude, shape, cool and cut to obtain an impact-resistant HDPE corrugated pipe.

[0032] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0033] 1. The elastic additive and composite auxiliary agent prepared in the present invention are added to the preparation process of HDPE corrugated pipes, which can effectively improve their impact resistance, low temperature resistance and chemical corrosion resistance.

[0034] 2. The present invention adds the prepared elastic additive to the HDPE corrugated pipe, which can effectively improve its impact resistance and low-temperature resistance. The elastic additive can serve as a dispersed phase in the HDPE matrix. When the corrugated pipe is impacted by external force, the elastic additive can serve as a stress concentration point, absorbing energy through stretching and fracture, and the shear band disperses stress through plastic deformation to prevent crack expansion. At the same time, the polar groups contained can be combined with the weak polar surface of HDPE through van der Waals force, thereby enhancing the interfacial bonding force and improving the impact resistance. The flexible chain segments contained in the elastic additive can still maintain high elasticity at low temperatures, delaying the embrittlement process of the corrugated pipe, and the flexible chain segments in the low-temperature environment can also move locally, absorb impact energy, and inhibit brittle fracture.

[0035] 3. The present invention adds the prepared composite additive to the HDPE corrugated pipe, which can effectively improve its impact resistance and chemical corrosion resistance. The composite additive can form a micron-level elastic dispersed phase in the HDPE matrix, and improve the impact resistance through silver streaks and shear band energy dissipation. At the same time, the carbon-fluorine bonds and low surface energy contained in the material give the material excellent chemical corrosion resistance. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] Example 1: This example discloses a method for preparing an elastic additive, comprising the following steps:

[0038] Q1: Under argon protection, 6.25 g of 2-amino-4-hydroxy-6-methylpyrimidine was added to a container, followed by 62.5 mL of hexamethylene diisocyanate and 5 mL of pyridine. The mixture was heated at 100°C with condensation and reflux, and stirred for 12 h. After the reaction, 16.5 mL of n-pentane was added, the mixture was filtered, washed with acetone, and dried to obtain intermediate 1.

[0039] Q2: Add 17.17 g of 2-amino-2-methyl-1,3-propanediol to a container, then add 31.7 g of intermediate 1, and then add 180 mL of chloroform. Under nitrogen protection, heat in an oil bath at 60°C for 12 h. After the reaction, cool, filter, dissolve, centrifuge, precipitate, filter, wash, and dry to obtain intermediate 2.

[0040] Q3: 208 g of oleic acid, 93.5 g of trimethylolpropane, 84.4 g of phthalic anhydride, and 12.15 g of neopentyl glycol were added to a container, followed by 32.3 g of xylene and 0.85 g of hypophosphorous acid. The mixture was heated to 155°C for 30 min and then heated to 220°C for 6 h. After the reaction, the mixture was cooled, rotary evaporated, and dried to obtain intermediate 3.

[0041] Q4: 10 g of intermediate 3 and 1.64 g of isophorone diisocyanate were added to a container, followed by 35 mL of N,N-dimethylformamide. Under nitrogen protection, the temperature was raised to 60°C for reaction for 4 h. After stirring evenly, 0.012 mL of dibutyltin dilaurate was added and the reaction continued. Subsequently, 0.93 g of intermediate 2 was added and the temperature was raised to 75°C for reaction for 1 h. After the reaction was completed, the mixture was rotary evaporated and dried to obtain an elastic additive.

[0042] This embodiment discloses a method for preparing a composite auxiliary agent, comprising the following steps:

[0043] S1: 6.6 g of 9-thioxanthone and 9.3 g of N-bromosuccinimide were added to a container containing 110 mL of dichloromethane, followed by dropwise addition of 3.33 mL of methanesulfonic acid, and the mixture was stirred at room temperature for 12 h. After the reaction, sodium sulfite was added, extracted, and the organic phases were combined, washed, dried, distilled under reduced pressure, and recrystallized to obtain product A. Under an argon atmosphere, 1.85 mL of diphenyl ether was added to 20 mL of tetrahydrofuran, and 4.38 mL of a 2.5 mol / L n-butyl lithium n-hexane solution was added at a low temperature of -78°C. After the addition was complete, the mixture was reacted at -78°C for 2 h, then at room temperature for 4 h, and then added to 10 mL of a tetrahydrofuran solution containing 2.1 g of product A, and the mixture was reacted for 12 h. After the reaction was completed, saturated ammonium chloride was added, extracted, vacuum distilled, dissolved, refluxed, cooled, diluted, washed, decompressed, and purified to obtain product B.

[0044] S2: 2.25 g of product B, 0.47 g of acetamide, 0.21 g of tris(dibenzylideneacetone)dipalladium, 0.38 g of 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene, and 3.75 g of cesium carbonate were added to a container. Under argon protection, 38 mL of 1,4-dioxane was added, stirred to dissolve, and heated under reflux at 105°C for 10 h. After the reaction, the mixture was cooled, diluted, washed, decompressed, and recrystallized to obtain product C.

[0045] S3: Add 1.49 g of product C to a mixed solution containing 10 mL of methanol and 6.5 mL of hydrochloric acid, heat at 55°C for 4 h, adjust the pH to 10, filter, and recrystallize to obtain product D;

[0046] S4: 0.5 g of product D, 0.55 g of 4,4'-(hexafluoroisopropylene) diphthalic anhydride, 0.13 mL of isoquinoline and 5.1 mL of m-cresol were added to a container. Under argon protection, the mixture was heated and stirred at 85°C for 6 h, and then continued to heat and stir at 190°C for 12 h. After the stirring was completed, the mixture was precipitated, filtered, dissolved, purified, and vacuum dried to obtain a composite auxiliary agent.

[0047] This embodiment discloses an impact-resistant HDPE corrugated pipe, characterized in that it is composed of the following components by weight: 75 parts of high-density polyethylene, 7 parts of polypropylene, 7 parts of elastic additives, 3.5 parts of adhesive resin, 2.5 parts of composite additives, 1.5 parts of ultraviolet absorbers, and 1.5 parts of antioxidants.

[0048] This embodiment discloses a method for preparing an impact-resistant HDPE corrugated pipe, comprising the following steps:

[0049] Step 1: Add high-density polyethylene, polypropylene, elastic additives, adhesive resin, composite additives, ultraviolet absorber and antioxidant into a high-speed mixer, mix well, and obtain a mixture;

[0050] Step 2: Add the mixed material into a twin-screw extruder, melt, mix and plasticize to obtain a uniform melt, extrude, shape, cool and cut to obtain an impact-resistant HDPE corrugated pipe.

[0051] Example 2: This example discloses a method for preparing an elastic additive, comprising the following steps:

[0052] Q1: Under argon protection, 5 g of 2-amino-4-hydroxy-6-methylpyrimidine was added to a container, followed by 75 mL of hexamethylene diisocyanate and 4 mL of pyridine. The mixture was heated at 100°C with reflux and stirred for 12 h. After the reaction, 15 mL of n-pentane was added, the mixture was filtered, washed with acetone, and dried to obtain intermediate 1.

[0053] Q2: Add 15 g of 2-amino-2-methyl-1,3-propanediol to a container, then add 33.4 g of intermediate 1, and then add 170 mL of chloroform. Under nitrogen protection, heat in an oil bath at 60°C for 12 h. After the reaction, cool, filter, dissolve, centrifuge, precipitate, filter, wash, and dry to obtain intermediate 2.

[0054] Q3: 216.2 g of oleic acid, 91.2 g of trimethylolpropane, 85 g of phthalic anhydride, and 10 g of neopentyl glycol were added to a container, followed by 34.6 g of xylene and 0.6 g of hypophosphorous acid. The mixture was heated to 155°C for 30 min and then heated to 220°C for 6 h. After the reaction, the mixture was cooled, rotary evaporated, and dried to obtain intermediate 3.

[0055] Q4: 12 g of intermediate 3 and 1.45 g of isophorone diisocyanate were added to a container, followed by 40 mL of N,N-dimethylformamide. Under nitrogen protection, the temperature was raised to 60°C for reaction for 4 h. After stirring evenly, 0.014 mL of dibutyltin dilaurate was added and the reaction continued. Subsequently, 0.85 g of intermediate 2 was added and the temperature was raised to 75°C for reaction for 1 h. After the reaction was completed, the mixture was rotary evaporated and dried to obtain an elastic additive.

[0056] This embodiment discloses a method for preparing a composite auxiliary agent, comprising the following steps:

[0057] S1: 5 g of 9-thioxanthone and 9.12 g of N-bromosuccinimide were added to a container containing 120 mL of dichloromethane, followed by dropwise addition of 3.12 mL of methanesulfonic acid, and the mixture was stirred at room temperature for 12 h. After the reaction, sodium sulfite was added, extracted, and the organic phases were combined, washed, dried, distilled under reduced pressure, and recrystallized to obtain product A. Under an argon atmosphere, 1.72 mL of diphenyl ether was added to 20 mL of tetrahydrofuran, and 4.12 mL of a 2.5 mol / L n-butyl lithium n-hexane solution was added at a low temperature of -78°C. After the addition was complete, the mixture was reacted at -78°C for 2 h, then at room temperature for 4 h, and then added to 10 mL of a tetrahydrofuran solution containing 2.2 g of product A, and the mixture was reacted for 12 h. After the reaction was completed, saturated ammonium chloride was added, extracted, vacuum distilled, dissolved, refluxed, cooled, diluted, washed, decompressed, and purified to obtain product B.

[0058] S2: 2.5 g of product B, 0.45 g of acetamide, 0.18 g of tris(dibenzylideneacetone)dipalladium, 0.32 g of 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene, and 3.54 g of cesium carbonate were added to a container. Under argon protection, 35 mL of 1,4-dioxane was added, stirred to dissolve, and heated under reflux at 105°C for 10 h. After the reaction, the mixture was cooled, diluted, washed, decompressed, and recrystallized to obtain product C;

[0059] S3: Add 1.25 g of product C to a mixed solution of 12 mL of methanol and 5 mL of hydrochloric acid, heat at 55°C for 4 h, adjust the pH to 10, filter, and recrystallize to obtain product D;

[0060] S4: 0.45 g of product D, 0.51 g of 4,4'-(hexafluoroisopropylene) diphthalic anhydride, 0.11 mL of isoquinoline and 4.8 mL of m-cresol were added to a container. Under argon protection, the mixture was heated and stirred at 85°C for 6 h, and then continued to heat and stir at 190°C for 12 h. After the stirring was completed, the mixture was precipitated, filtered, dissolved, purified, and vacuum dried to obtain a composite auxiliary agent.

[0061] This embodiment discloses an impact-resistant HDPE corrugated pipe, characterized in that it is composed of the following components by weight: 70 parts of high-density polyethylene, 5 parts of polypropylene, 9 parts of elastic additives, 2 parts of adhesive resin, 1 part of composite auxiliary agent, 1 part of ultraviolet absorber, and 1 part of antioxidant.

[0062] This embodiment discloses a method for preparing an impact-resistant HDPE corrugated pipe, comprising the following steps:

[0063] Step 1: Add high-density polyethylene, polypropylene, elastic additives, adhesive resin, composite additives, ultraviolet absorber and antioxidant into a high-speed mixer, mix well, and obtain a mixture;

[0064] Step 2: Add the mixed material into a twin-screw extruder, melt, mix and plasticize to obtain a uniform melt, extrude, shape, cool and cut to obtain an impact-resistant HDPE corrugated pipe.

[0065] Example 3: This example discloses a method for preparing an elastic additive, comprising the following steps:

[0066] Q1: Under argon protection, 7.5 g of 2-amino-4-hydroxy-6-methylpyrimidine was added to a container, followed by 50 mL of hexamethylene diisocyanate and 6 mL of pyridine. The mixture was heated at 100°C with reflux and stirred for 12 h. After the reaction, 20 mL of n-pentane was added, the mixture was filtered, washed with acetone, and dried to obtain intermediate 1.

[0067] Q2: Add 19.34 g of 2-amino-2-methyl-1,3-propanediol to a container, then add 30 g of intermediate 1, and then add 190 mL of chloroform. Under nitrogen protection, heat in an oil bath at 60°C for 12 h. After the reaction, cool, filter, dissolve, centrifuge, precipitate, filter, wash, and dry to obtain intermediate 2.

[0068] Q3: 200 g of oleic acid, 96.4 g of trimethylolpropane, 89.9 g of phthalic anhydride, and 14.3 g of neopentyl glycol were added to a container, followed by 30 g of xylene and 1.1 g of hypophosphorous acid. The mixture was heated to 155°C for 30 min and then heated to 220°C for 6 h. After the reaction, the mixture was cooled, rotary evaporated, and dried to obtain intermediate 3.

[0069] Q4: 8 g of intermediate 3 and 1.83 g of isophorone diisocyanate were added to a container, followed by 30 mL of N,N-dimethylformamide. Under nitrogen protection, the temperature was raised to 60°C for reaction for 4 h. After stirring evenly, 0.01 mL of dibutyltin dilaurate was added and the reaction continued. Subsequently, 1.02 g of intermediate 2 was added and the temperature was raised to 75°C for reaction for 1 h. After the reaction was completed, the mixture was rotary evaporated and dried to obtain an elastic additive.

[0070] This embodiment discloses a method for preparing a composite auxiliary agent, comprising the following steps:

[0071] S1: 7.2 g of 9-thioxanthone and 9.48 g of N-bromosuccinimide were added to a container containing 105 mL of dichloromethane, followed by dropwise addition of 3.54 mL of methanesulfonic acid, and the mixture was stirred at room temperature for 12 h. After the reaction, sodium sulfite was added, extracted, and the organic phases were combined, washed, dried, distilled under reduced pressure, and recrystallized to obtain product A. Under an argon atmosphere, 1.98 mL of diphenyl ether was added to 20 mL of tetrahydrofuran, and 4.65 mL of a 2.5 mol / L n-butyl lithium n-hexane solution was added at a low temperature of -78°C. After the addition was complete, the mixture was reacted at -78°C for 2 h, then at room temperature for 4 h, and then added to 10 mL of a tetrahydrofuran solution containing 2 g of product A, and the mixture was reacted for 12 h. After the reaction was completed, saturated ammonium chloride was added, extracted, vacuum distilled, dissolved, refluxed, cooled, diluted, washed, decompressed, and purified to obtain product B.

[0072] S2: 2 g of product B, 0.49 g of acetamide, 0.25 g of tris(dibenzylideneacetone)dipalladium, 0.45 g of 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene, and 3.95 g of cesium carbonate were added to a container. Under argon protection, 42 mL of 1,4-dioxane was added, stirred to dissolve, and heated under reflux at 105°C for 10 h. After the reaction, the mixture was cooled, diluted, washed, decompressed, and recrystallized to obtain product C.

[0073] S3: Add 1.73 g of product C to a mixed solution of 8 mL of methanol and 8 mL of hydrochloric acid, heat at 55°C for 4 h, adjust the pH to 10, filter, and recrystallize to obtain product D;

[0074] S4: 0.55 g of product D, 0.62 g of 4,4'-(hexafluoroisopropylene) diphthalic anhydride, 0.16 mL of isoquinoline and 5.4 mL of m-cresol were added to a container. Under argon protection, the mixture was heated and stirred at 85°C for 6 h, and then continued to heat and stir at 190°C for 12 h. After the stirring was completed, the mixture was precipitated, filtered, dissolved, purified, and vacuum dried to obtain a composite auxiliary agent.

[0075] This embodiment discloses an impact-resistant HDPE corrugated pipe, characterized in that it is composed of the following components by weight: 80 parts of high-density polyethylene, 9 parts of polypropylene, 5 parts of elastic additives, 5 parts of adhesive resin, 4 parts of composite additives, 2 parts of ultraviolet absorbers, and 2 parts of antioxidants.

[0076] This embodiment discloses a method for preparing an impact-resistant HDPE corrugated pipe, comprising the following steps:

[0077] Step 1: Add high-density polyethylene, polypropylene, elastic additives, adhesive resin, composite additives, ultraviolet absorber and antioxidant into a high-speed mixer, mix well, and obtain a mixture;

[0078] Step 2: Add the mixed material into a twin-screw extruder, melt, mix and plasticize to obtain a uniform melt, extrude, shape, cool and cut to obtain an impact-resistant HDPE corrugated pipe.

[0079] Comparative Example 1: Compared with Example 1, in the process of preparing the impact-resistant HDPE corrugated pipe in Comparative Example 1, no elastic additive is added, and other conditions remain unchanged.

[0080] Comparative Example 2: Compared with Example 1, in Comparative Example 2, during the preparation of the impact-resistant HDPE corrugated pipe, no composite additive was added, and other conditions remained unchanged.

[0081] Experimental Example: The performance of the impact-resistant HDPE corrugated pipes prepared in Examples 1-3 and Comparative Examples 1-2 was tested. The impact resistance of the samples was tested in accordance with GB / T 14152-2001. The samples were placed in a -35°C environment, and then the tensile strength of the samples was tested in accordance with GB / T 1040.2-2022. The reduction rate of tensile strength before and after the experiment was calculated. The samples were placed in a solution with a hydrochloric acid content of 10wt% or in a solution with an alkali content of 10wt% for 0.5h and then inspected at room temperature to see if there was any significant change in appearance. The test results are shown in Table 1:

[0082] Table 1

[0083]

[0084] The test results in Table 1 indicate that the HDPE corrugated pipes prepared in Examples 1-3 of the present invention exhibit excellent impact resistance, low-temperature resistance, and chemical corrosion resistance. A comparison of Comparative Example 1 with Examples 1-3 demonstrates that the addition of an elastic additive effectively improves the impact resistance and low-temperature resistance of HDPE corrugated pipes. A comparison of Comparative Example 2 with Examples 1-3 demonstrates that the addition of a composite additive improves the impact resistance and chemical corrosion resistance of HDPE corrugated pipes.

[0085] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0086] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An impact-resistant HDPE corrugated pipe, characterized in that: The invention is composed of the following components in parts by weight: 70-80 parts of high-density polyethylene, 5-9 parts of polypropylene, 5-9 parts of elastic additives, 2-5 parts of adhesive resin, 1-4 parts of composite auxiliary agent, 1-2 parts of ultraviolet absorber, and 1-2 parts of antioxidant; The preparation method of the composite auxiliary agent comprises the following steps: S1: 9-thioxanthone and N-bromosuccinimide are added to a container containing dichloromethane, followed by dropwise addition of methanesulfonic acid, and the mixture is stirred at room temperature for reaction. After the reaction is completed, sodium sulfite is added, extracted, the organic phases are combined, washed, dried, distilled under reduced pressure, and recrystallized to obtain product A. Under an argon atmosphere, diphenyl ether is added to tetrahydrofuran, and a n-hexane solution of n-butyl lithium is added at low temperature. After the dropwise addition is completed, the mixture is reacted at low temperature and then at room temperature. The mixture is then added to a tetrahydrofuran solution containing product A and reacted. After the reaction is completed, saturated ammonium chloride is added, extracted, vacuum distilled, dissolved, refluxed, cooled, diluted, washed, decompressed, and purified to obtain product B. S2: Add product B, acetamide, tris(dibenzylideneacetone)dipalladium, 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene, and cesium carbonate to a container. Under argon protection, add 1,4-dioxane, stir to dissolve, heat under reflux to react, and after the reaction is completed, cool, dilute, wash, reduce pressure, and recrystallize to obtain product C; S3: adding product C to a mixed solution of methanol and hydrochloric acid, heating for reaction, adjusting the pH, filtering, and recrystallizing to obtain product D; S4: adding product D, 4,4'-(hexafluoroisopropylene) diphthalic anhydride, isoquinoline and m-cresol into a container, heating and stirring under argon protection, then continuing heating and stirring, precipitating, filtering, dissolving, purifying and vacuum drying to obtain a composite auxiliary agent; The preparation method of the elastic additive comprises the following steps: Q1: Under argon protection, 2-amino-4-hydroxy-6-methylpyrimidine was added to a container, followed by hexamethylene diisocyanate and pyridine. The mixture was heated, condensed, refluxed, and stirred for reaction. After the reaction was completed, n-pentane was added, the mixture was filtered, washed, and dried to obtain intermediate 1. Q2: Add 2-amino-2-methyl-1,3-propanediol to a container, then add intermediate 1, and then add chloroform. Under nitrogen protection, heat in an oil bath to react. After the reaction is completed, cool, filter, dissolve, centrifuge, precipitate, filter, wash, and dry to obtain intermediate 2; Q3: Add oleic acid, trimethylolpropane, phthalic anhydride and neopentyl glycol to a container, then add xylene and hypophosphorous acid, heat the reaction, continue to heat the reaction, cool, rotary evaporate and dry to obtain intermediate 3; Q4: Add intermediate 3 and isophorone diisocyanate to a container, then add N,N-dimethylformamide, and heat the reaction under nitrogen protection. After stirring evenly, add dibutyltin dilaurate and continue the reaction. Then add intermediate 2, heat the reaction and continue the reaction. After the reaction is completed, rotary evaporate and dry to obtain an elastic additive.

2. The impact-resistant HDPE corrugated pipe according to claim 1, characterized in that: In Q1, the usage ratio of 2-amino-4-hydroxy-6-methylpyrimidine, hexamethylene diisocyanate, pyridine and n-pentane is (5-7.5) g: (50-75) mL: (4-6) mL: (15-20) mL; in Q2, the usage ratio of 2-amino-2-methyl-1,3-propanediol, intermediate 1 and chloroform is (15-19.34) g: (30-33.4) g: (170-190) mL.

3. The impact-resistant HDPE corrugated pipe according to claim 1, characterized in that: In Q3, the usage ratio of oleic acid, trimethylolpropane, phthalic anhydride, neopentyl glycol, xylene and hypophosphorous acid is (200-216.2) g: (91.2-96.4) g: (85-89.9) g: (10-14.3) g: (30-34.6) g: (0.6-1.1) g; in Q4, the usage ratio of intermediate 3, isophorone diisocyanate, N,N-dimethylformamide, dibutyltin dilaurate and intermediate 2 is (8-12) g: (1.45-1.83) g: (30-40) mL: (0.01-0.014) mL: (0.85-1.02) g.

4. The impact-resistant HDPE corrugated pipe according to claim 1, characterized in that: In S1, the usage ratio of 9-thioxanthone, N-bromosuccinimide, dichloromethane and methanesulfonic acid is (5-7.2) g: (9.12-9.48) g: (100-120) mL: (3.12-3.54) mL; the usage ratio of diphenyl ether, n-hexane solution and product A is (1.72-1.98) mL: (4.12-4.65) mL: (2-2.2) g.

5. The impact-resistant HDPE corrugated pipe according to claim 1, characterized in that: In S2, the usage ratio of product B, acetamide, tris(dibenzylideneacetone)dipalladium, 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene, cesium carbonate and 1,4-dioxane is (2-2.5) g: (0.45-0.49) g: (0.18-0.25) g: (0.32-0.45) g: (3.54-3.95) g: (35-42) mL; in S3, the usage ratio of product C, methanol and hydrochloric acid is (1.25-1.73) g: (8-12) mL: (5-8) mL.

6. The impact-resistant HDPE corrugated pipe according to claim 1, characterized in that: In the above-mentioned S4, the usage ratio of the product D, 4,4'-(hexafluoroisopropylene) diphthalic anhydride, isoquinoline and m-cresol is (0.45-0.55) g: (0.51-0.62) g: (0.11-0.16) mL: (4.8-5.4) mL.

7. The method for preparing an impact-resistant HDPE corrugated pipe according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Add high-density polyethylene, polypropylene, elastic additives, adhesive resin, composite additives, ultraviolet absorber and antioxidant into a high-speed mixer, mix well, and obtain a mixture; Step 2: Add the mixed material into a twin-screw extruder, melt, mix and plasticize to obtain a uniform melt, extrude, shape, cool and cut to obtain an impact-resistant HDPE corrugated pipe.

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