Impact-resistant pe pipe and method for producing the same

Abstract

The application relates to an anti-impact PE pipe and a preparation method thereof, and belongs to the technical field of polymer composite materials. The components of the PE pipe are as follows: calcium carbonate whiskers 6.2-9.5 wt%, an anti-impact modifier 4.4-5.8 wt%, a lubricant 0.2-0.3 wt%, an antioxidant 0.15-0.2 wt%, an ultraviolet absorber 0.11-0.14 wt% and color master granules 2.6-3.2 wt%, and the balance is polyethylene resin. The disulfide structure in the molecular chain of the anti-impact modifier is loaded between the calcium carbonate whiskers in the form of multi-point anchoring through chelation to form a reinforcing and impact energy dispersion network, meanwhile, the polycyclohexyl segment in the molecular chain forms a large number of "microvesicle" unit structures on the surface of the calcium carbonate whiskers, absorbs impact energy and uniformly disperses and transitions the impact energy through the slippage deformation of the vesicle structure, and the anti-impact performance of the PE pipe is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite material technology, specifically, it relates to an impact-resistant PE pipe and its preparation method. Background Technology

[0002] Polyethylene (PE) pipes have become the mainstream material in municipal water supply and drainage, gas transmission, and industrial fluid transportation due to their excellent corrosion resistance, flexibility, and low cost. Among them, high-density polyethylene (HDPE), as a branch of the polyethylene family with higher mechanical strength, is widely used in high-pressure water pipes and gas pipe systems due to its high crystallinity, high softening point, and excellent cold resistance and wear resistance.

[0003] To enhance the strength of high-density polyethylene (HDPE) pipes, existing technologies commonly employ inorganic filler reinforcement strategies, such as adding calcium carbonate, talc, and glass microspheres. While these fillers significantly improve the tensile strength and modulus of the pipes, they also increase brittleness and deteriorate impact resistance. To compensate for the brittleness caused by fillers, existing technologies mainly rely on two methods, both of which have significant limitations: 1. Coupling treatment: using silane or titanate coupling agents to bridge the filler and resin matrix through chemical bonds, improving filler dispersibility and interfacial compatibility. However, coupling agents only optimize interfacial bonding and cannot fundamentally improve the toughness of the matrix, thus insufficiently improving the impact resistance of the pipes; 2. Toughening treatment: using elastomer toughening agents to weaken the intermolecular forces of the polyethylene matrix, which can improve the impact resistance of the pipes to some extent, but reduces pipe strength. Furthermore, heterogeneous toughening agents exacerbate stress cracking, which is detrimental to the reinforcement effect of fillers. The shortcomings of existing technologies seriously hinder the development of high-performance impact-resistant PE pipes. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background art, the purpose of this invention is to provide an impact-resistant PE pipe and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] An impact-resistant PE pipe, by weight percentage, has the following specific components:

[0007] The composition includes 6.2-9.5 wt% calcium carbonate whiskers, 4.4-5.8 wt% impact modifier, 0.2-0.3 wt% lubricant, 0.15-0.2 wt% antioxidant, 0.11-0.14 wt% UV absorber, and 2.6-3.2 wt% color masterbatch, with the balance being polyethylene resin.

[0008] The impact modifier is prepared by the following method:

[0009] Step A1: Mix 1,4-butanediol, triethylamine and anhydrous tetrahydrofuran, add dicyclohexyldichlorosilane under a dry atmosphere and sonicate for 0.5-0.8 h, then add ethylene glycol and heat to 50-60℃ and stir for 1.2-1.8 h. After the reaction is complete, filter to remove salt, remove tetrahydrofuran by rotary evaporation, wash with deionized water, separate the aqueous phase and dry to obtain the diol monomer;

[0010] In step A1, the molar ratio of dicyclohexyldichlorosilane, 1,4-butanediol, ethylene glycol, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 70-85 mmol: 30-50 mmol: 15-20 mL: 60-80 mL. Dicyclohexyldichlorosilane and 1,4-butanediol undergo a substitution reaction, followed by end-capping with ethylene glycol to form a chain compound containing a large number of cyclohexyl groups. The specific reaction route is as follows:

[0011]

[0012] Step A2: Mix undecenoic acid, ethylenedithiol, photosensitizer, and dimethyl sulfoxide thoroughly, and apply at 40-50 mW / cm². 2 Irradiate with ultraviolet light and stir at room temperature for 2.5-3.2 h. After the reaction is complete, add deionized water to wash and separate the aqueous phase to elute dimethyl sulfoxide. Then, remove water by rotary evaporation under reduced pressure and remove residual dimethyl sulfoxide to obtain the dicarboxylic acid monomer.

[0013] In step A2, the ratio of undecenoic acid, ethylene dithiol, photosensitizer, and dimethyl sulfoxide is 0.1 mol: 52-55 mmol: 20-25 mg: 35-45 mL. Undecenoic acid and ethylene dithiol undergo an addition reaction under photoinitiation. The specific reaction route is as follows:

[0014]

[0015] Step A3: Mix the diol monomer, diacid monomer and tetrabutyl titanate, and esterify them at 160-180℃ under nitrogen protection for 2.7-3.3h. Then reduce the pressure to 100Pa and heat to 200-220℃ for 1.5-2h. After the reaction is completed, discharge and cool to obtain the impact modifier.

[0016] In step A3, the molar ratio of alcohol to diacid monomer is 1.02-1.04:1, and the amount of tetrabutyl titanate is 0.35-0.4 wt%. The diol monomer and diacid monomer undergo esterification and polycondensation to form a macromolecular chain. The specific reaction route is as follows:

[0017]

[0018] Preferably, the length of the calcium carbonate whiskers is 30-80 μm. Whiskers of this size have good dispersibility and can also play a good physical strengthening role.

[0019] Preferably, the lubricant is a combination of polyethylene wax and calcium stearate, which provides both internal and external lubrication, facilitates pipe forming, and promotes the dispersion of calcium carbonate whiskers.

[0020] A method for preparing impact-resistant PE pipe, specifically comprising:

[0021] Step S1: Mix 1 / 3 of the weight of polyethylene resin with the remaining components, heat to 160-170℃ to melt and mix, discharge and cool, then crush to obtain composite masterbatch;

[0022] Step S2: Mix the remaining polyethylene resin with the composite masterbatch, feed it into the pipe making machine for plasticizing and extrusion at 200-210℃, and cool and shape it to obtain impact-resistant PE pipe.

[0023] Preferably, the melt pressure during the plasticizing and extrusion process is 18-22 MPa, resulting in uniform pipe wall thickness, stable dimensions, dense pipe wall, and high overall performance.

[0024] The beneficial effects of this invention are:

[0025] This invention discloses a preparation scheme for PE pipes synergistically modified with an impact modifier and calcium carbonate whiskers. The impact modifier is prepared by a substitution reaction of dicyclohexyldichlorosilane and 1,4-butanediol to form a cyclohexyl-rich compound, which is then end-capped with ethylene glycol to form a diol monomer. This monomer is then formed by the click addition of undecenoic acid and ethylene dithiol to form a diacid monomer. Finally, the diol monomer and the diacid monomer are esterified to form a macromolecular compound, which is the impact modifier. After blending modification, the disulfide structure in the impact modifier molecular chain forms a chelating effect with the calcium carbonate whiskers. The impact modifier is loaded between calcium carbonate whiskers in a multi-point anchoring manner to form an organic-inorganic reinforcing network, while simultaneously constructing a bridge for impact energy transfer. The polycyclohexyl segments in the molecular chain of the impact modifier have good compatibility with HDPE, a large spatial structure, and no additional interaction with calcium carbonate whiskers. As a result, a large number of "microvesicle" unit structures are formed on the surface of calcium carbonate whiskers. When subjected to external forces, the "microvesicle" structure absorbs the impact energy, and the energy is uniformly dispersed and transferred through the sliding deformation of the vesicle structure, effectively improving the impact resistance of PE pipes. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments 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.

[0027] Example 1: Preparation of impact-resistant PE pipes. The specific implementation process is as follows:

[0028] (1) Preparation of impact modifier

[0029] Step A1: Mix 1,4-butanediol, triethylamine, and anhydrous tetrahydrofuran, purge with dry nitrogen for protection, add dicyclohexyldichlorosilane, and sonicate at 25 kHz for 0.8 h. Then add ethylene glycol and heat to 50 °C with stirring for 1.8 h. The ratio of dicyclohexyldichlorosilane, 1,4-butanediol, ethylene glycol, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 85 mmol: 30 mmol: 15 mL: 60 mL. After the reaction is complete, filter to remove salt, remove tetrahydrofuran by rotary evaporation, wash with deionized water, separate the aqueous phase, and dry to obtain the diol monomer.

[0030] Step A2: Mix undecenoic acid, ethylenedithiol, photosensitizer, and dimethyl sulfoxide, and apply at 40 mW / cm². 2 The reaction was carried out under ultraviolet irradiation and stirred at room temperature for 3.2 h. The photosensitizer used was photoinitiator 1173. The ratio of undecenoic acid, ethylene dithiol, photosensitizer and dimethyl sulfoxide was 0.1 mol: 52 mmol: 20 mg: 35 mL. After the reaction was completed, deionized water was added for washing. The aqueous phase was separated to elute the dimethyl sulfoxide. The water was then removed by rotary evaporation under reduced pressure, and the residual dimethyl sulfoxide was removed to obtain the dicarboxylic acid monomer.

[0031] Step A3: Take diol monomer and diacid monomer at an alcohol-acid molar ratio of 1.02:1, add 0.35wt% tetrabutyl titanate and mix well. Purge with nitrogen for protection, heat to 160℃ and esterify for 3.3h. Then reduce the pressure to 100Pa and heat to 200℃ for polymerization for 2h. After the reaction is completed, discharge and cool to obtain the impact modifier.

[0032] (2) Preparation of impact-resistant PE pipes

[0033] The ingredients are formulated as follows: 6.2 wt% calcium carbonate whiskers, commercially available whiskers with a length distribution of 30-40 μm; 4.4 wt% impact modifier, prepared in this embodiment; 0.3 wt% lubricant, a mixture of polyethylene wax and calcium stearate in a weight ratio of 2:1; 0.2 wt% antioxidant, a mixture of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:1; 0.14 wt% UV absorber, UV-531 type raw material; 2.6 wt% masterbatch, commercially available black masterbatch; the balance is 6380M type high-density polyethylene resin.

[0034] Step S1: Add 1 / 3 of the weight of polyethylene resin and the remaining components to a high-speed mixer and mix them evenly. Add the mixture to an internal mixer and melt-mix at 160°C. After cooling, pulverize the discharged material to obtain composite masterbatch.

[0035] Step S2: Add the remaining polyethylene resin and composite masterbatch to a high-speed mixer and mix them evenly. Then, feed the mixture into a pipe-making machine and extrude it at 200°C. Control the parameters of the extruder and adjust the melt pressure to the range of 18-20 MPa during the extrusion process. The extruded pipe is then cooled and shaped by spraying to obtain impact-resistant PE pipe.

[0036] Example 2: Preparation of impact-resistant PE pipes. The specific implementation process is as follows:

[0037] (1) Preparation of impact modifier

[0038] Step A1: Mix 1,4-butanediol, triethylamine, and anhydrous tetrahydrofuran, purge with dry nitrogen for protection, add dicyclohexyldichlorosilane, and sonicate at 20 kHz for 0.6 h. Then add ethylene glycol and heat to 50 °C with stirring for 1.4 h. The ratio of dicyclohexyldichlorosilane, 1,4-butanediol, ethylene glycol, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 80 mmol: 40 mmol: 15 mL: 70 mL. After the reaction is complete, filter to remove salt, remove tetrahydrofuran by rotary evaporation, wash with deionized water, separate the aqueous phase, and dry to obtain the diol monomer.

[0039] Step A2: Mix undecenoic acid, ethylenedithiol, photosensitizer, and dimethyl sulfoxide, and apply at 50 mW / cm². 2 The reaction was carried out under ultraviolet irradiation and stirred at room temperature for 3 hours. The photosensitizer used was photoinitiator 1173. The ratio of undecenoic acid, ethylene dithiol, photosensitizer and dimethyl sulfoxide was 0.1 mol: 55 mmol: 20 mg: 40 mL. After the reaction was completed, deionized water was added for washing. The aqueous phase was separated to elute the dimethyl sulfoxide. The water was then removed by rotary evaporation under reduced pressure, and the residual dimethyl sulfoxide was removed to obtain the dicarboxylic acid monomer.

[0040] Step A3: Take diol monomer and diacid monomer at an alcohol-acid molar ratio of 1.02:1, add 0.38wt% tetrabutyl titanate and mix well. Purge with nitrogen for protection, heat to 170℃ for esterification reaction for 3 hours, then reduce pressure to 100Pa and heat to 210℃ for polymerization reaction for 1.7 hours. After the reaction is completed, discharge and cool to obtain the impact modifier.

[0041] (2) Preparation of impact-resistant PE pipes

[0042] The ingredients are formulated as follows: 8.5 wt% calcium carbonate whiskers, commercially available whiskers with a length distribution of 30-40 μm; 5.2 wt% impact modifier, prepared in this embodiment; 0.25 wt% lubricant, selected from polyethylene wax and calcium stearate in a weight ratio of 2:1; 0.17 wt% antioxidant, selected from antioxidant 1010 and antioxidant 168 in a weight ratio of 1:1; 0.12 wt% UV absorber, selected from UV-531 type raw material; 3.2 wt% color masterbatch, selected from commercially available black masterbatch; the balance is 6380M type high-density polyethylene resin.

[0043] Step S1: Add 1 / 3 of the weight of polyethylene resin and the remaining components to a high-speed mixer and mix them evenly. Add the mixture to an internal mixer and melt-mix at 170°C. After cooling, pulverize the discharged material to obtain composite masterbatch.

[0044] Step S2: Add the remaining polyethylene resin and composite masterbatch to a high-speed mixer and mix them evenly. Then, feed the mixture into a pipe-making machine and extrude it at 200°C. Control the parameters of the extruder and adjust the melt pressure to the range of 18-20 MPa during the extrusion process. The extruded pipe is then cooled and shaped by spraying to obtain impact-resistant PE pipe.

[0045] Example 3: Preparation of impact-resistant PE pipes. The specific implementation process is as follows:

[0046] (1) Preparation of impact modifier

[0047] Step A1: Mix 1,4-butanediol, triethylamine, and anhydrous tetrahydrofuran, purge with dry nitrogen for protection, add dicyclohexyldichlorosilane, and sonicate at 20 kHz for 0.5 h. Then add ethylene glycol and heat to 60 °C with stirring for 1.2 h. The ratio of dicyclohexyldichlorosilane, 1,4-butanediol, ethylene glycol, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 70 mmol: 50 mmol: 20 mL: 80 mL. After the reaction is complete, filter to remove salt, remove tetrahydrofuran by rotary evaporation, wash with deionized water, separate the aqueous phase, and dry to obtain the diol monomer.

[0048] Step A2: Mix undecenoic acid, ethylenedithiol, photosensitizer, and dimethyl sulfoxide, and apply at 50 mW / cm². 2The reaction was carried out under ultraviolet irradiation and stirred at room temperature for 2.5 h. The photosensitizer used was photoinitiator 1173. The ratio of undecenoic acid, ethylene dithiol, photosensitizer and dimethyl sulfoxide was 0.1 mol: 55 mmol: 25 mg: 45 mL. After the reaction was completed, deionized water was added and the mixture was washed. The aqueous phase was separated and the dimethyl sulfoxide was eluted. The water was then removed by rotary evaporation under reduced pressure, and the residual dimethyl sulfoxide was removed to obtain the dicarboxylic acid monomer.

[0049] Step A3: Take diol monomer and diacid monomer at an alcohol-acid molar ratio of 1.04:1, add 0.4wt% tetrabutyl titanate and mix well. Purge with nitrogen for protection, heat to 180℃ and esterify for 2.7h. Then reduce the pressure to 100Pa and heat to 220℃ for polymerization for 1.5h. After the reaction is completed, discharge and cool to obtain the impact modifier.

[0050] (2) Preparation of impact-resistant PE pipes

[0051] The ingredients are formulated as follows: 9.5 wt% calcium carbonate whiskers, commercially available whiskers with a length distribution of 50-80 μm; 5.8 wt% impact modifier, prepared in this embodiment; 0.2 wt% lubricant, a mixture of polyethylene wax and calcium stearate in a weight ratio of 2:1; 0.15 wt% antioxidant, a mixture of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:1; 0.11 wt% UV absorber, UV-531 type raw material; 3 wt% masterbatch, commercially available black masterbatch; the balance is 6380M type high-density polyethylene resin.

[0052] Step S1: Add 1 / 3 of the weight of polyethylene resin and the remaining components to a high-speed mixer and mix them evenly. Add the mixture to an internal mixer and melt-mix at 170°C. After cooling, pulverize the discharged material to obtain composite masterbatch.

[0053] Step S2: Add the remaining polyethylene resin and composite masterbatch to a high-speed mixer and mix them evenly. Then, feed the mixture into a pipe-making machine and plasticize and extrude it at 210°C. Control the parameters of the extruder and adjust the melt pressure during the extrusion process to a range of 20-22 MPa. The extruded pipe is then cooled and shaped by spraying to obtain impact-resistant PE pipe.

[0054] Example 4: Preparation of impact-resistant PE pipes. The specific implementation process is as follows:

[0055] (1) Preparation of impact modifier

[0056] Step A1: Mix 1,4-butanediol, triethylamine, and anhydrous tetrahydrofuran, purge with dry nitrogen for protection, add dicyclohexyldichlorosilane, and sonicate at 25 kHz for 0.7 h. Then add ethylene glycol and heat to 55 °C with stirring for 1.5 h. The ratio of dicyclohexyldichlorosilane, 1,4-butanediol, ethylene glycol, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 75 mmol: 40 mmol: 18 mL: 70 mL. After the reaction is complete, filter to remove salt, remove tetrahydrofuran by rotary evaporation, wash with deionized water, separate the aqueous phase, and dry to obtain the diol monomer.

[0057] Step A2: Mix undecenoic acid, ethylenedithiol, photosensitizer, and dimethyl sulfoxide, and apply at 45 mW / cm². 2 The reaction was carried out under ultraviolet irradiation and stirred at room temperature for 2.8 h. The photosensitizer used was photoinitiator 1173. The ratio of undecenoic acid, ethylene dithiol, photosensitizer and dimethyl sulfoxide was 0.1 mol: 55 mmol: 25 mg: 45 mL. After the reaction was completed, deionized water was added and the mixture was washed. The aqueous phase was separated to elute the dimethyl sulfoxide. The water was then removed by rotary evaporation under reduced pressure, and the residual dimethyl sulfoxide was removed to obtain the dicarboxylic acid monomer.

[0058] Step A3: Take diol monomer and diacid monomer at an alcohol-acid molar ratio of 1.03:1, add 0.4wt% tetrabutyl titanate and mix well. Purge with nitrogen for protection, heat to 180℃ and esterify for 2.9h. Then reduce the pressure to 100Pa and heat to 220℃ for polymerization for 1.7h. After the reaction is completed, discharge and cool to obtain the impact modifier.

[0059] (2) Preparation of impact-resistant PE pipes

[0060] The ingredients are formulated as follows: 8 wt% calcium carbonate whiskers, commercially available whiskers with a length distribution of 50-80 μm; 4.9 wt% impact modifier, prepared in this embodiment; 0.25 wt% lubricant, selected from polyethylene wax and calcium stearate in a weight ratio of 2:1; 0.18 wt% antioxidant, selected from antioxidant 1010 and antioxidant 168 in a weight ratio of 1:1; 0.13 wt% UV absorber, selected from UV-531 type raw material; 2.8 wt% color masterbatch, selected from commercially available black masterbatch; the balance is 6380M type high-density polyethylene resin.

[0061] Step S1: Add 1 / 3 of the weight of polyethylene resin and the remaining components to a high-speed mixer and mix them evenly. Add the mixture to an internal mixer and melt-mix at 160°C. After cooling, pulverize the discharged material to obtain composite masterbatch.

[0062] Step S2: Add the remaining polyethylene resin and composite masterbatch to a high-speed mixer and mix them evenly. Then, feed the mixture into a pipe-making machine and plasticize and extrude it at 210°C. Control the parameters of the extruder and adjust the melt pressure during the extrusion process to a range of 20-22 MPa. The extruded pipe is then cooled and shaped by spraying to obtain impact-resistant PE pipe.

[0063] Comparative Example 1: POE toughening was used to improve impact resistance in accordance with existing technology. The specific implementation process is the same as in Example 4. Based on existing production experience, the impact modifier was replaced with 7.5 wt% LC575 type POE toughening agent, and the balance was adjusted from polyethylene resin to 100 wt%. The rest of the implementation process was exactly the same.

[0064] Comparative Example 2, referring to existing interface treatment technology and based on existing production experience, uses 1.5 wt% cyclohexyltrimethoxysilane to replace the impact modifier, and adjusts the balance to 100 wt% from polyethylene resin. The rest of the implementation process is exactly the same.

[0065] Samples were taken from the above-mentioned pipes, and ring stiffness tests were performed according to ISO 9969:2016 standard, with compression at a rate of 5 mm / min until 3% deformation; drop hammer impact tests were performed according to GB / T 14152-2001 standard, with an impact height of 2 m and a hammer head curvature radius of 25 mm; impact strength tests were performed according to ISO 180:2023 standard, with a 2 mm deep V-notch and a pendulum energy of 5.5 J; environmental stress cracking time tests were performed according to GB / T 1842-2008 standard, and the cracking time of 50% of the samples was recorded; the specific test results are shown in Table 1.

[0066]

[0067] As shown in Table 1, the pipe prepared in the example has a higher ring stiffness than the comparative example, indicating that the introduction of the impact modifier has a strengthening effect on the pipe. The notched impact strength of the example is significantly higher than that of the comparative example, and the drop hammer impact failure rate is significantly lower than that of the comparative example, indicating that the impact modifier plays an excellent role in improving impact resistance.

[0068] In the description of this specification, the 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 present invention. In this specification, the 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.

[0069] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. An impact-resistant PE pipe, characterized in that, The specific components are: 6.2-9.5 wt% calcium carbonate whiskers, 4.4-5.8 wt% impact modifier, 0.2-0.3 wt% lubricant, 0.15-0.2 wt% antioxidant, 0.11-0.14 wt% UV absorber, and 2.6-3.2 wt% color masterbatch, with the balance being polyethylene resin; The impact modifier is prepared by the following method: Step A1: Mix 1,4-butanediol, triethylamine, and anhydrous tetrahydrofuran. Add dicyclohexyldichlorosilane under a dry atmosphere and sonicate for 0.5-0.8 h. Then add ethylene glycol and heat to 50-60℃ and stir for 1.2-1.8 h to prepare a diol monomer. The ratio of dicyclohexyldichlorosilane, 1,4-butanediol, ethylene glycol, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 70-85 mmol: 30-50 mmol: 15-20 mL: 60-80 mL. Step A2: Mix undecenoic acid, ethylenedithiol, photosensitizer, and dimethyl sulfoxide thoroughly, and apply at 40-50 mW / cm². 2 The reaction was carried out under ultraviolet irradiation and stirred at room temperature for 2.5-3.2 hours to prepare a dicarboxylic acid monomer, wherein the ratio of undecenoic acid, ethylenedithiol, photosensitizer and dimethyl sulfoxide was 0.1 mol: 52-55 mmol: 20-25 mg: 35-45 mL. Step A3: Mix the diol monomer, diacid monomer and tetrabutyl titanate, and esterify them at 160-180℃ under nitrogen protection for 2.7-3.3h. Then reduce the pressure to 100Pa and heat to 200-220℃ for 1.5-2h. After the reaction is completed, discharge and cool to obtain the impact modifier.

2. The impact-resistant PE pipe according to claim 1, characterized in that, The molar ratio of alcohol to diacid monomer is 1.02-1.04:1, and the amount of tetrabutyl titanate is 0.35-0.4wt%.

3. The impact-resistant PE pipe according to claim 1, characterized in that, The length of calcium carbonate whiskers is 30-80 μm.

4. The impact-resistant PE pipe according to claim 1, characterized in that, The lubricant is a combination of polyethylene wax and calcium stearate.

5. A method for preparing impact-resistant PE pipe according to any one of claims 1-4, characterized in that, Specifically: Step S1: Mix 1 / 3 of the weight of polyethylene resin with the remaining components, heat to 160-170℃ to melt and mix, discharge and cool, then crush to obtain composite masterbatch; Step S2: Mix the remaining polyethylene resin with the composite masterbatch, feed it into the pipe making machine for plasticizing and extrusion at 200-210℃, and cool and shape it to obtain impact-resistant PE pipe.

6. The method for preparing an impact-resistant PE pipe according to claim 5, characterized in that, The melt pressure during plasticizing and extrusion is 18-22 MPa.

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