Environment-friendly high-toughness PE pipe and preparation process thereof

Abstract

The invention relates to the technical field of pipes, in particular to an environment-friendly high-toughness PE pipe and a preparation process thereof. The environment-friendly high-toughness PE pipe is prepared from the following components in parts by weight: 40 to 70 parts of pretreated recycled PE materials, 20 to 35 parts of PE powder, 1 to 4 parts of silicon dioxide, 3 to 6 parts of talcum powder, 1 to 4 parts of a toughening agent, 2 to 6 parts of a compatilizer, 3 to 7 parts of a dispersing agent, 1 to 3 parts of a lubricating agent and 4 to 8 parts of an anti-aging toughening additive. The anti-aging toughening additive is obtained by carrying out grafting reaction on silane modified carbon fibers and an anti-aging agent. According to the environment-friendly high-toughness PE pipe prepared by the invention, the aging resistance of the PE pipe is improved, the problem that the PE pipe is easy to brittle fracture is effectively improved, and the mechanical property of the PE pipe is improved, so that the service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe materials, and particularly relates to an environmentally friendly and highly tough PE pipe and its preparation process. Background Art

[0002] With the rapid development of social economy, various plastic products are used in people's daily life. After these plastic products are discarded, they are not easily degraded and are discarded at will, and the problem of "white pollution" has caused serious impacts on the ecological environment, causing serious pollution to the natural environment, soil, ocean, etc. during long-term use, and even threatening human health. These waste plastics are difficult to degrade in the natural environment and can only be treated by incineration or burial. However, a lot of harmful gases will be generated during the incineration process, causing great harm to the environment. During the burial treatment, the toxic substances of some plastic materials will seep out, causing secondary pollution and affecting the utilization value of the land. Therefore, the recycling of these waste plastic products is a technical problem that needs to be solved.

[0003] The recycling of waste plastic products refers to classifying and recycling waste plastics and then reprocessing them for use, or decomposing and converting them into heat energy or other high-value-added chemicals for use. Therefore, the recycling of waste plastics can reduce environmental pollution, improve the circular economic value of plastics, and promote energy conservation and environmental protection. However, waste plastic products are prone to aging, mainly in two aspects: on the one hand, the structural properties of the polymer itself, such as unsaturated double bonds, branched chain groups, etc.; on the other hand, during the processing, use and recycling processes, under the action of light, heat, oxygen and external forces during use, the high molecular chain structure will change, the molecular chain will break and oxidize, resulting in a decrease in molecular weight, and the mechanical properties (such as strength, toughness) and thermal stability of the material will deteriorate irreversibly, thus causing the material properties to decline or even leading to damage, so that it cannot be used. Therefore, there is an urgent need to develop a high-performance and highly tough PE pipe and its preparation process. Summary of the Invention

[0004] In view of the above deficiencies in the prior art, the present invention provides an environmentally friendly and highly tough PE pipe and its preparation process.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: An environmentally friendly and highly tough PE pipe is composed of the following parts by weight: 40 - 70 parts by weight of pretreated PE waste material recycled material, 20 - 35 parts by weight of PE powder, 1 - 4 parts by weight of silicon dioxide, 3 - 6 parts by weight of talcum powder, 1 - 4 parts by weight of toughening agent, 2 - 6 parts by weight of compatibilizer, 3 - 7 parts by weight of dispersant, 1 - 3 parts by weight of lubricant, 4 - 8 parts by weight of anti-aging and toughening additive; the anti-aging and toughening additive is obtained by grafting reaction of silane-modified carbon fiber and anti-aging agent.

[0006] After multiple processing of old PE materials, their molecular structure changes, resulting in poor interfacial compatibility with new materials or other additives. And during long-term use, antioxidants and stabilizers may have been exhausted, leading to a significant decline in their anti-aging performance. The decline in anti-aging performance will accelerate the degradation of the material in the use environment and shorten the service life, and its performance defects greatly limit its application. Therefore, in order to make up for the performance defects of recycled old PE materials, it is necessary to add anti-aging and toughening additives.

[0007] Carbon fiber has extremely high specific strength and specific modulus, excellent heat resistance and oxidation resistance, can delay the aging of PE pipes in high-temperature or ultraviolet environments, and can significantly improve the mechanical properties such as tensile strength and impact resistance of PE pipes. Carbon fiber can not only absorb and disperse external stress, but also inhibit the fracture and degradation of PE molecular chains, reduce the stress concentration of the PE matrix, thereby improving the toughness of the pipe and extending the service life of the pipe.

[0008] In order to improve the anti-aging performance and mechanical properties of PE pipes and avoid the influence on the use performance, the present invention conducts composite modification on carbon materials to improve the toughness of the pipes and extend the service life.

[0009] Preferably, the preparation method of the anti-aging and toughening additive is as follows: Activate the carbon material to obtain pretreated carbon material, take 8-14 parts by weight of the pretreated carbon material and 150-300 parts by weight of an ethanol aqueous solution and mix them by ultrasonic, then add 2-6 parts by weight of aminosilane and heat and stir to obtain silane-modified carbon material; Under the environment of nitrogen, react 4-8 parts by weight of butyric acid derivative, 3-7 parts by weight of triethylamine and 20-30 parts by weight of 4-amino-2,6-di-tert-butylphenol by stirring to obtain an antioxidant; Stir 8-12 parts by weight of the above silane-modified carbon material and 15-26 parts by weight of the antioxidant at room temperature, then add 0.5-2 parts by weight of N,N'-diisopropylcarbodiimide, and stir and react at 50-70 °C and 400-800 rpm for 3-6 h to obtain the anti-aging and toughening additive.

[0010] The specific reaction mechanism is as follows: S1 Place the carbon material in nitric acid for heating activation to introduce active groups (such as hydroxyl groups, carboxyl groups, etc.) on the surface of the carbon fiber, improve its surface reaction activity, and provide reaction sites for the subsequent grafting of silane coupling agents; The aminosilane undergoes a condensation reaction with the hydroxyl group (-OH) on the surface of the carbon fiber to form a Si-O-C bond, and at the same time introduce an amino group (-NH 2Functional groups such as (-SO 3 H), -Cl as strong leaving groups, react with the amino group (-NH 2 )) in 4-amino-2,6-di-tert-butylphenol through nucleophilic substitution reaction to form an amide bond (-CONH-), and the resulting antioxidant has phenolic hydroxyl groups and amide bonds, which can capture free radicals and inhibit the oxidative degradation of PE molecular chains; S3 uses silane-modified carbon materials and antioxidants as reaction raw materials, and N,N'-diisopropylcarbodiimide (DIC) as a catalyst. Under the conditions of heating and stirring, the amino group (-NH 2 )) on the surface of the silane-modified carbon fiber reacts with the carboxyl group (-COOH) in the antioxidant to form an amide bond (-CONH-), and through chemical bonding, the antioxidant is firmly grafted onto the surface of the silane-modified carbon fiber to form a composite material with anti-aging and toughening functions.

[0011] Furthermore, the preparation method of the anti-aging and toughening additive is as follows: S1. Add 150 - 300 parts by weight of 40 - 60wt% ethanol aqueous solution to 8 - 14 parts by weight of carbon materials, add 3 - 5 parts by weight of 1 - 4mol / L nitric acid solution, activate at 60 - 80°C for 2 - 5h, filter, wash, and dry to obtain pretreated carbon fibers. Take 8 - 12 parts by weight of pretreated carbon fibers and 150 - 300 parts by weight of 40 - 60wt% ethanol aqueous solution and mix them. Ultrasonic for 15 - 300min at an ultrasonic power of 100 - 300W and an ultrasonic frequency of 40 - 70kHz, then add 2 - 6 parts by weight of amino silane and mix evenly. Stir at 80 - 120°C and 300 - 500rpm for 6 - 16h, centrifuge, wash, and dry to obtain silane-modified carbon fibers; S2. Under the environment of nitrogen, mix 4 - 8 parts by weight of butyric acid derivatives and 60 - 100 parts by weight of cyclohexane evenly, add 3 - 7 parts by weight of triethylamine and 20 - 30 parts by weight of 4-amino-2,6-di-tert-butylphenol, react at 35 - 50°C and 200 - 500rpm for 2 - 5h, and perform vacuum distillation to obtain the antioxidant; S3. Mix 8 - 12 parts by weight of the above silane - modified carbon fiber and 80 - 200 parts by weight of N,N - dimethylformamide evenly, add 15 - 26 parts by weight of the anti - aging agent, stir at 400 - 800 rpm for 40 - 90 min at room temperature, then add 0.5 - 2 parts by weight of N,N'-diisopropylcarbodiimide, stir and react at 50 - 70 °C and 400 - 800 rpm for 3 - 6 h, centrifuge, wash, dry, and grind to obtain the anti - aging and toughening additive.

[0012] The anti - aging and toughening additive prepared by the present invention can effectively capture free radicals in the polymer degradation chain reaction, inhibit the oxidative degradation of the PE molecular chain to achieve the anti - aging effect. The anti - aging and toughening additive can combine the carbon material and the organic anti - aging mechanism, combine the advantages of both, and have stable and efficient anti - aging performance. In addition, through grafting and compounding, an organic coating layer can be formed on the surface of the carbon material anti - aging filler, which can effectively improve the uniform dispersion of the carbon material anti - aging filler in the PE pipe, improve the chemical bonding between the carbon fiber, the PE matrix and the anti - aging agent, improve the interfacial bonding force, reduce stress concentration. The introduced carbon material as a reinforcing phase can effectively absorb and disperse external stress, reduce the crack propagation of the PE matrix, and significantly improve the toughness, impact resistance and interfacial compatibility of the PE material. The anti - aging agent can capture free radicals, inhibit the oxidative degradation of the PE molecular chain, inhibit the breakage of the PE molecular chain, and further improve the toughness. The two act synergistically through chemical bonding and physical mixing, and the anti - aging and toughening additive is evenly dispersed in the PE matrix. When applied to environmentally friendly high - toughness PE pipes, it can significantly improve the toughness and anti - aging performance of the PE pipes.

[0013] Preferably, the carbon material is any one of carbon fiber, single - walled carbon nanotube, multi - walled carbon nanotube, and white carbon black.

[0014] Preferably, the amino - silane is at least one of 3 - aminopropyldiisopropylethoxysilane, 3 - [bis(2 - hydroxyethyl)amino]propane - triethoxysilane, and 1,3 - bis(3 - aminopropyl)-1,1,3,3 - tetramethyldisiloxane; preferably, the amino - silane is 1,3 - bis(3 - aminopropyl)-1,1,3,3 - tetramethyldisiloxane.

[0015] This application preferably uses 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane as the aminosilane. The possible reason is that 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane contains two aminopropyl groups and one tetramethyldisiloxane, providing more reactive sites and being able to form stronger chemical bonds with the hydroxyl (-OH) or carboxyl (-COOH) groups on the surface of carbon fiber. The tetramethyldisiloxane structure has high thermal and chemical stability, can maintain its properties during high-temperature processing and long-term use, is not easily degraded, and shows significant advantages in toughening and anti-aging. On the contrary, 3-aminopropyldiisopropylethoxysilane and 3-[bis(2-hydroxyethyl)amino]propane-triethoxysilane contain ethoxy (-OCH 2 CH 3 ), or hydroxyethyl (-CH 2 CH 2 OH) groups, and these groups are prone to hydrolysis or oxidation in high-temperature or humid environments, resulting in the destruction of the molecular structure and affecting the stability of the material.

[0016] Preferably, the butyric acid derivative is one or any two of 4-methylsulfonic acid butyric acid, 4-chlorobutyric acid, and 4-bromobutyric acid; preferably, the butyric acid derivative is 4-methylsulfonic acid butyric acid.

[0017] The possible reason for this application to preferably use 4-methylsulfonic acid butyric acid as the butyric acid derivative is that 4-methylsulfonic acid butyric acid can form stable amide bonds during the reaction and generate an antioxidant with excellent anti-aging performance due to its strongly polar methylsulfonic acid group and high reactivity. However, 4-chlorobutyric acid cannot achieve the same technical effect due to the low reactivity of the chlorine atom, easy occurrence of side reactions, and poor product performance. Therefore, using 4-methylsulfonic acid butyric acid as the butyric acid derivative in this application has a better effect on anti-aging performance.

[0018] Preferably, the toughening agent is at least one of diisononyl phthalate, ethylene-vinyl acetate copolymer, methyl methacrylate-butadiene-styrene, ethylene propylene diene monomer, and styrene-butadiene.

[0019] Preferably, the compatibilizer is at least one of maleic anhydride grafted styrene and maleic anhydride grafted propylene.

[0020] Preferably, the dispersant is at least one of N,N'-ethylenebisstearamide, fatty alcohol polyoxyethylene ether sulfate, polyvinyl alcohol, calcium stearate, methyl amyl alcohol, and monoglyceride stearate.

[0021] Preferably, the lubricant is at least one of stearic acid, polypropylene wax, and chlorinated paraffin.

[0022] The preparation process of the environmentally friendly high-toughness PE pipe includes the following steps: (1) Crush the recycled PE waste material, and obtain the crushed raw material through sieving; wash the crushed raw material with a mixed solvent and dry it; heat and extrude the dried raw material using a co - rotating twin - screw extruder and then cool it to obtain the pretreated recycled PE waste material; (2) Weigh various raw materials according to the weight - part ratio; take the pretreated recycled PE waste material, PE powder, silicon dioxide, talcum powder, toughening agent, compatibilizer, dispersant, and lubricant and stir them in a blender at 1200 - 1800 rpm for 15 - 40 min to obtain a mixed material; (3) Put the mixed material into a reactor. After the temperature rises to 100 - 130 °C, add the anti - aging and toughening additive, continue to raise the temperature to 140 - 160 °C and stir for 20 - 500 min, then cool and stir until the material temperature is 50 - 70 °C, and then add it into a twin - screw extruder. Under the conditions that the melting temperature is set with the feeding temperature being 150 - 180 °C, the extrusion head temperature being 220 - 260 °C, and the screw speed being 120 - 260 rpm, carry out melt extrusion and plasticizing granulation to obtain the environmentally friendly and highly tough PE pipe.

[0023] Advantages of the present invention: 1. The present invention provides an environmentally friendly and highly tough PE pipe and its preparation process, which not only improves the aging resistance of the PE pipe, but also effectively solves the problem that the PE pipe is prone to brittle fracture, improves the mechanical properties of the PE pipe, thereby increasing the service life, saving costs, and being suitable for large - scale popularization and use.

[0024] 2. The present invention uses recycled PE waste material as a raw material. Although it has environmental and economic advantages, the degradation of molecular chains, impurity pollution, poor interfacial compatibility, and decline in anti - aging performance during the processing process limit its application. By adding an anti - aging and toughening additive, it can effectively repair the molecular chain structure, enhance toughness, improve interfacial compatibility, improve anti - aging performance, and improve processing performance. This not only makes up for the performance defects of the recycled PE waste material, but also realizes the dual goals of environmental protection and economy, providing a feasible technical path for the high - value utilization of recycled PE materials. Detailed implementation mode

[0025] The following further describes in detail the above - mentioned inventive content of the present invention in combination with specific implementation modes, but this should not be understood that the scope of the above - mentioned subject matter of the present invention is limited to the following embodiments.

[0026] Introduction of some raw materials in this application. All other raw material substances not introduced are commercially available: The recycled PE waste material is purchased from Congtai District Hongxuan Renewable Resources Recycling Department, with a tensile strength of 21 MPa.

[0027] The PE powder is purchased from Shenzhen Longdi Chemical Co., Ltd., with the model XH9160WMZRVC.

[0028] The ethylene-vinyl acetate copolymer was purchased from Shanghai Hongze Juheng Plastic Raw Materials Co., Ltd., with the grade UE630.

[0029] Maleic anhydride grafted styrene was purchased from Dongguan Chuangyu New Materials Co., Ltd., with the model AX-4002.

[0030] The carbon fiber was purchased from Xinfuda (Zhenjiang) High-Performance Materials Co., Ltd., with the grade Tepla® T8035LCF. Example 1

[0031] An environmentally friendly high-toughness PE pipe is composed of the following parts by weight: 50 parts by weight of pretreated PE waste material recycled material, 24 parts by weight of PE powder, 2 parts by weight of silica, 4 parts by weight of talc powder, 3 parts by weight of toughening agent, 4 parts by weight of compatibilizer, 5 parts by weight of dispersant, 2 parts by weight of lubricant, and 6 parts by weight of anti-aging and toughening additive.

[0032] The toughening agent is ethylene-vinyl acetate copolymer.

[0033] The compatibilizer is maleic anhydride grafted styrene.

[0034] The dispersant is N,N'-ethylenebisstearamide.

[0035] The lubricant is stearic acid.

[0036] The anti-aging and toughening additive is obtained by mixing 10 parts by weight of carbon fiber and 20 parts by weight of 4-amino-2,6-di-tert-butylphenol.

[0037] The preparation process of the environmentally friendly high-toughness PE pipe includes the following steps (1) Crush the recycled PE waste material, and pass it through a 40-mesh sieve to obtain the crushed raw material; wash the crushed raw material with a mixed solvent of ethanol and dichloromethane with a volume ratio of 1:1, and dry it; heat and extrude the dried raw material using a co-rotating extruder, and cool it to obtain the pretreated recycled PE waste material; (2) Weigh various raw materials according to the weight ratio; take the pretreated recycled PE waste material, PE powder, silica, talc powder, toughening agent, compatibilizer, dispersant, and lubricant and stir them in a mixer at 1500 rpm for 20 min to obtain a mixed material; (3) Put the mixed material into a reactor. After the temperature rises to 120 °C, add the anti-aging and toughening additive, continue to heat up to 150 °C and stir for 30 min, cool and stir until the material temperature is 60 °C, and then add it to a twin-screw extruder. Under the conditions that the melting temperature is set with the inlet temperature of 160 °C, the extrusion head temperature of 240 °C, and the screw speed of 200 rpm, carry out melting extrusion and plasticizing molding to granulate, and obtain the environmentally friendly high-toughness PE pipe. Example 2

[0038] An environmentally friendly high-toughness PE pipe is composed of the following parts by weight: 50 parts by weight of recycled material of pretreated PE waste material, 24 parts by weight of PE powder, 2 parts by weight of silica, 4 parts by weight of talc powder, 3 parts by weight of toughening agent, 4 parts by weight of compatibilizer, 5 parts by weight of dispersant, 2 parts by weight of lubricant, and 6 parts by weight of anti-aging and toughening additive.

[0039] The toughening agent is ethylene-vinyl acetate copolymer.

[0040] The compatibilizer is maleic anhydride grafted styrene.

[0041] The dispersant is N,N'-ethylenebisstearamide.

[0042] The lubricant is stearic acid.

[0043] The preparation method of the anti-aging and toughening additive is as follows: S1. Add 200 parts by weight of 50wt% ethanol aqueous solution to 12 parts by weight of carbon fiber, add 4 parts by weight of 2mol / L nitric acid solution, activate at 70°C for 3h, filter, wash, and dry to obtain pretreated carbon fiber. Take 10 parts by weight of pretreated carbon fiber and 200 parts by weight of 50wt% ethanol aqueous solution and mix them. Ultrasonic at an ultrasonic power of 200W and an ultrasonic frequency of 60kHz for 20min, then add 3 parts by weight of amino silane and mix evenly. Stir at 100°C and 400rpm for 10h, centrifuge, wash, and dry to obtain silane-modified carbon fiber; the amino silane is 3-aminopropyldiisopropylethoxysilane; S2. Under the environment of nitrogen, mix 6 parts by weight of 4-methylsulfonic acid butyrate and 80 parts by weight of cyclohexane evenly, add 5 parts by weight of triethylamine and 25 parts by weight of 4-amino-2,6-di-tert-butylphenol, react at 40°C and 400rpm for 3h, and perform vacuum distillation to obtain an antioxidant; S3. Mix 10 parts by weight of the above silane-modified carbon fiber and 100 parts by weight of N,N-dimethylformamide evenly, add 20 parts by weight of the antioxidant, stir at room temperature and 600rpm for 60min, then add 1 part by weight of N,N'-diisopropylcarbodiimide, stir and react at 60°C and 600rpm for 4h, centrifuge, wash, dry, and grind to obtain the anti-aging and toughening additive.

[0044] The preparation process of the environmentally friendly high-toughness PE pipe includes the following steps (1) Crush the recycled PE waste material, and pass it through a 40-mesh sieve to obtain the crushed raw material; wash the crushed raw material with a mixed solvent of ethanol and dichloromethane in a volume ratio of 1:1, and dry it; heat and extrude the dried raw material using a co-melting extruder, and cool it to obtain the pretreated recycled PE waste material; (2) Weigh various raw materials according to the weight ratio; take the pretreated recycled PE waste material, PE powder, silica, talcum powder, toughening agent, compatibilizer, dispersant, and lubricant, and stir them in a blender at 1500 rpm for 20 min to obtain a mixed material; (3) Put the mixed material into a reactor. After the temperature rises to 120 °C, add the anti-aging and toughening additive, continue to heat up to 150 °C and stir for 30 min, cool and stir until the material temperature is 60 °C, then add it to a twin-screw extruder, and carry out melt extrusion and plasticizing granulation under the conditions that the melting temperature is set at 160 °C for the inlet temperature, 240 °C for the extrusion head, and 200 rpm for the screw speed to obtain the environmentally friendly high-toughness PE pipe. Example 3

[0045] An environmentally friendly high-toughness PE pipe is composed of the following parts by weight: 50 parts by weight of pretreated recycled PE waste material, 24 parts by weight of PE powder, 2 parts by weight of silica, 4 parts by weight of talcum powder, 3 parts by weight of toughening agent, 4 parts by weight of compatibilizer, 5 parts by weight of dispersant, 2 parts by weight of lubricant, and 6 parts by weight of anti-aging and toughening additive.

[0046] The toughening agent is ethylene-vinyl acetate copolymer.

[0047] The compatibilizer is maleic anhydride grafted styrene.

[0048] The dispersant is N,N'-ethylenebisstearamide.

[0049] The lubricant is stearic acid.

[0050] The preparation method of the anti-aging and toughening additive is as follows: S1. Add 200 parts by weight of 50 wt% ethanol aqueous solution to 12 parts by weight of carbon fiber, add 4 parts by weight of 2 mol / L nitric acid solution, activate at 70 °C for 3 h, filter, wash, and dry to obtain pretreated carbon fiber. Take 10 parts by weight of pretreated carbon fiber and 200 parts by weight of 50 wt% ethanol aqueous solution and mix them. Ultrasonic at a ultrasonic power of 200 W and a ultrasonic frequency of 60 kHz for 20 min, then add 3 parts by weight of amino silane and mix evenly. Stir at 100 °C and 400 rpm for 10 h, centrifuge, wash, and dry to obtain silane-modified carbon fiber; the amino silane is 3-[bis(2-hydroxyethyl)amino]propane-triethoxysilane; S2. Under a nitrogen environment, mix 6 parts by weight of butyric acid 4 - mesylate and 80 parts by weight of cyclohexane evenly, add 5 parts by weight of triethylamine and 25 parts by weight of 4 - amino - 2,6 - di - tert - butylphenol, react at 40 °C and 400 rpm for 3 h, and perform vacuum distillation to obtain an antioxidant. S3. Mix 10 parts by weight of the above - mentioned silane - modified carbon fiber and 100 parts by weight of N,N - dimethylformamide evenly, add 20 parts by weight of the antioxidant, stir at room temperature and 600 rpm for 60 min, then add 1 part by weight of N,N'-diisopropylcarbodiimide, stir and react at 60 °C and 600 rpm for 4 h, centrifuge, wash, dry, and grind to obtain an antioxidant and toughness - enhancing additive.

[0051] The preparation process of the environmentally friendly high - toughness PE pipe includes the following steps (1) Crush the recycled PE old material, pass through a 40 - mesh sieve to obtain a crushed raw material; wash the crushed raw material with a mixed solvent of ethanol and dichloromethane with a volume ratio of 1:1, and dry; heat - extrude and cool the dried raw material using a co - melting extruder to obtain a pretreated recycled PE old material. (2) Weigh various raw materials according to the parts - by - weight ratio; take the pretreated recycled PE old material, PE powder, silica, talc powder, toughening agent, compatibilizer, dispersant, and lubricant, and stir in a blender at 1500 rpm for 20 min to obtain a mixed material. (3) Put the mixed material into a reactor. After the temperature rises to 120 °C, add the antioxidant and toughness - enhancing additive, continue to raise the temperature to 150 °C and stir for 30 min, cool and stir until the material temperature is 60 °C, then add it to a twin - screw extruder, and perform melt extrusion and plasticizing granulation under the conditions that the melting temperature is set with the inlet temperature of 160 °C, the extrusion head temperature of 240 °C, and the screw speed of 200 rpm to obtain the environmentally friendly high - toughness PE pipe. Example 4

[0052] An environmentally friendly high - toughness PE pipe is composed of the following parts by weight: 50 parts by weight of pretreated recycled PE old material, 24 parts by weight of PE powder, 2 parts by weight of silica, 4 parts by weight of talc powder, 3 parts by weight of toughening agent, 4 parts by weight of compatibilizer, 5 parts by weight of dispersant, 2 parts by weight of lubricant, and 6 parts by weight of antioxidant and toughness - enhancing additive.

[0053] The toughening agent is ethylene - vinyl acetate copolymer.

[0054] The compatibilizer is maleic anhydride - grafted styrene.

[0055] The dispersant is N,N'-ethylenebisstearamide.

[0056] The lubricant is stearic acid.

[0057] The preparation method of the anti-aging and toughening additive is as follows: S1. Add 200 parts by weight of 50 wt% ethanol aqueous solution to 12 parts by weight of carbon fiber, add 4 parts by weight of 2 mol / L nitric acid solution, activate at 70 °C for 3 h, filter, wash, and dry to obtain pretreated carbon fiber. Take 10 parts by weight of the pretreated carbon fiber and 200 parts by weight of 50 wt% ethanol aqueous solution and mix them. Ultrasonic for 20 min at an ultrasonic power of 200 W and an ultrasonic frequency of 60 kHz, then add 3 parts by weight of amino silane and mix evenly. Stir at 100 °C and 400 rpm for 10 h, centrifuge, wash, and dry to obtain silane-modified carbon fiber; the amino silane is 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane; S2. Under the environment of nitrogen, mix 6 parts by weight of 4-methylsulfonic acid butyrate and 80 parts by weight of cyclohexane evenly, add 5 parts by weight of triethylamine and 25 parts by weight of 4-amino-2,6-di-tert-butylphenol, react at 40 °C and 400 rpm for 3 h, and carry out vacuum distillation to obtain the anti-aging agent; S3. Mix 10 parts by weight of the above-mentioned silane-modified carbon fiber and 100 parts by weight of N,N-dimethylformamide evenly, add 20 parts by weight of the anti-aging agent, stir at room temperature and 600 rpm for 60 min, then add 1 part by weight of N,N'-diisopropylcarbodiimide, stir and react at 60 °C and 600 rpm for 4 h, centrifuge, wash, dry, and grind to obtain the anti-aging and toughening additive.

[0058] The preparation process of the environmentally friendly high-toughness PE pipe includes the following steps (1) Crush the recycled PE old material, and pass through a 40-mesh sieve to obtain the crushed raw material; wash the crushed raw material with a mixed solvent of ethanol and dichloromethane with a volume ratio of 1:1, and dry; heat and extrude the dried raw material with a co-melt extruder and cool to obtain the pretreated recycled PE old material; (2) Weigh various raw materials according to the weight ratio; take the pretreated recycled PE old material, PE powder, silica, talc powder, toughening agent, compatibilizer, dispersant, and lubricant and stir in a mixer at 1500 rpm for 20 min to obtain a mixed material; (3) Put the mixed material into a reactor. After the temperature rises to 120 °C, add the anti-aging and toughening additive, continue to heat to 150 °C and stir for 30 min, cool and stir until the material temperature is 60 °C, then add it to a twin-screw extruder, and carry out melt extrusion and plastic forming granulation under the conditions that the melt temperature is set to 160 °C for the inlet temperature, 240 °C for the extrusion head, and 200 rpm for the screw speed to obtain the environmentally friendly high-toughness PE pipe. Example 5

[0059] An environmentally friendly and highly tough PE pipe is composed of the following parts by weight: 50 parts by weight of recycled pre-treated PE waste materials, 24 parts by weight of PE powder, 2 parts by weight of silicon dioxide, 4 parts by weight of talcum powder, 3 parts by weight of toughening agent, 4 parts by weight of compatibilizer, 5 parts by weight of dispersant, 2 parts by weight of lubricant, and 6 parts by weight of anti-aging and toughening additive.

[0060] The toughening agent is ethylene-vinyl acetate copolymer.

[0061] The compatibilizer is maleic anhydride grafted styrene.

[0062] The dispersant is N,N'-ethylenebisstearamide.

[0063] The lubricant is stearic acid.

[0064] The preparation method of the anti-aging and toughening additive is as follows: S1. Add 200 parts by weight of 50wt% ethanol aqueous solution to 12 parts by weight of carbon fiber, add 4 parts by weight of 2mol / L nitric acid solution, activate at 70°C for 3h, filter, wash, and dry to obtain pre-treated carbon fiber. Take 10 parts by weight of pre-treated carbon fiber and 200 parts by weight of 50wt% ethanol aqueous solution and mix them. Ultrasonic at an ultrasonic power of 200W and an ultrasonic frequency of 60kHz for 20min, then add 3 parts by weight of amino silane and mix evenly. Stir at 100°C and 400rpm for 10h, centrifuge, wash, and dry to obtain silane-modified carbon fiber; the amino silane is 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane; S2. Mix 10 parts by weight of the above silane-modified carbon fiber and 100 parts by weight of N,N-dimethylformamide evenly, add 20 parts by weight of 4-amino-2,6-di-tert-butylphenol, stir at room temperature and 600rpm for 60min, then add 1 part by weight of N,N'-diisopropylcarbodiimide, stir and react at 60°C and 600rpm for 4h, centrifuge, wash, dry, and grind to obtain the anti-aging and toughening additive.

[0065] The preparation process of the environmentally friendly and highly tough PE pipe includes the following steps (1) Crush the recycled PE waste materials, pass through a 40-mesh sieve to obtain crushed raw materials; wash the crushed raw materials with a mixed solvent of ethanol and dichloromethane with a volume ratio of 1:1, and dry; heat and extrude the dried raw materials with a co-rotating twin-screw extruder and cool to obtain pre-treated recycled PE waste materials; (2) Weigh various raw materials according to the parts by weight ratio; take the pre-treated recycled PE waste materials, PE powder, silicon dioxide, talcum powder, toughening agent, compatibilizer, dispersant, and lubricant and stir in a mixer at 1500rpm for 20min to obtain a mixed material; (3) Put the mixed materials into the reactor. After the temperature rises to 120°C, add the anti-aging and toughening additive, continue to heat up to 150°C and stir for 30 minutes, cool and stir until the material temperature is 60°C, then add it to the twin-screw extruder. Under the conditions that the melting temperature is set at 160°C for the inlet temperature, 240°C for the extrusion head, and the screw speed is 200 rpm, carry out melt extrusion and plasticizing granulation to obtain the environmentally friendly high-toughness PE pipe. Example 6

[0066] An environmentally friendly high-toughness PE pipe consists of the following parts by weight: 50 parts by weight of recycled pre-treated PE waste materials, 24 parts by weight of PE powder, 2 parts by weight of silica, 4 parts by weight of talc powder, 3 parts by weight of toughening agent, 4 parts by weight of compatibilizer, 5 parts by weight of dispersant, 2 parts by weight of lubricant, 6 parts by weight of anti-aging and toughening additive.

[0067] The toughening agent is ethylene-vinyl acetate copolymer.

[0068] The compatibilizer is maleic anhydride grafted styrene.

[0069] The dispersant is N,N'-ethylenebisstearamide.

[0070] The lubricant is stearic acid.

[0071] The preparation method of the anti-aging and toughening additive is as follows: S1. Add 200 parts by weight of 50 wt% ethanol aqueous solution to 12 parts by weight of carbon fiber, add 4 parts by weight of 2 mol / L nitric acid solution, activate at 70°C for 3 h, filter, wash, and dry to obtain pre-treated carbon fiber. Take 10 parts by weight of pre-treated carbon fiber and 200 parts by weight of 50 wt% ethanol aqueous solution and mix them. Ultrasonic at 200 W ultrasonic power and 60 kHz ultrasonic frequency for 20 minutes, then add 3 parts by weight of amino silane and mix evenly. Stir at 100°C and 400 rpm for 10 h, centrifuge, wash, and dry to obtain silane-modified carbon fiber; the amino silane is 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane; S2. Under the environment of nitrogen, mix 6 parts by weight of 4-chlorobutyric acid and 80 parts by weight of cyclohexane evenly, add 5 parts by weight of triethylamine and 25 parts by weight of 4-amino-2,6-di-tert-butylphenol, react at 40°C and 400 rpm for 3 h, and carry out vacuum distillation to obtain the anti-aging agent; S3. Mix 10 parts by weight of the above-mentioned silane-modified carbon fiber and 100 parts by weight of N,N-dimethylformamide evenly, add 20 parts by weight of the anti-aging agent, stir at 600 rpm for 60 min at room temperature, then add 1 part by weight of N,N'-diisopropylcarbodiimide, and stir and react at 60 °C and 600 rpm for 4 h. Centrifuge, wash, dry, and grind to obtain the anti-aging and toughening additive.

[0072] The preparation process of the environmentally friendly high-toughness PE pipe includes the following steps (1) Crush the PE waste material recycling material, and pass through a 40-mesh sieve to obtain the crushed raw material; wash the crushed raw material with a mixed solvent of ethanol and dichloromethane with a volume ratio of 1:1, and dry it; heat and extrude the dried raw material with a co-melt extruder and cool it to obtain the pretreated PE waste material recycling material; (2) Weigh various raw materials according to the weight ratio; take the pretreated PE waste material recycling material, PE powder, silica, talc powder, toughening agent, compatibilizer, dispersant, and lubricant and stir in a blender at 1500 rpm for 20 min to obtain the mixed material; (3) Put the mixed material into the reactor. After the temperature rises to 120 °C, add the anti-aging and toughening additive, continue to heat up to 150 °C and stir for 30 min, cool and stir until the material temperature is 60 °C, then add it to the twin-screw extruder, and carry out melt extrusion and plasticizing granulation under the conditions that the melting temperature is set at 160 °C for the inlet temperature, 240 °C for the extrusion head, and 200 rpm for the screw speed to obtain the environmentally friendly high-toughness PE pipe.

[0073] Test Example 1 Aging resistance performance test: Refer to the regulations and standards in the national standard GB / T16422.2-2022 "Plastics - Methods of exposure to laboratory light sources - Part 2: Xenon-arc lamps". Take a sheet with a length of 10 cm and a width (arc length) of 5 cm, and measure its surface gloss. Place the PE pipe sample in a xenon lamp accelerated aging chamber for accelerated aging test. After irradiating for 2000 h, use a glossmeter to measure the gloss retention rate (light retention rate) of the pipe surface. The xenon lamp aging test chamber is X65, with a water-cooled xenon lamp and an irradiation intensity of 60 W / ㎡, and carry out accelerated aging according to the above test method, then measure the surface gloss of the sheet again, calculate the light retention rate before and after aging, and test 5 times for each group and take the average value. The test results are shown in Table 1.

[0074] Table 1 Anti-aging test results Light retention rate (%) Example 1 65 Example 2 93 Example 3 95 Example 4 99 Example 5 72 Example 6 85

[0075] Test Example 2 Tensile property test: The environmentally friendly high-toughness PE pipe obtained in the example was injection-molded, and the test was carried out with reference to the method of national standard GB / T 1040.2-2022 "Plastics - Determination of tensile properties - Part 2: Test conditions for moulded and extruded plastics"; the test specimen was a dumbbell shape of type 1A, with a thickness of 4 mm and a test speed of 1 mm / min. Before the test, the sample was conditioned at a temperature of 23 °C and a relative humidity of 50% for 24 h. There were 6 parallel groups, and the average value was taken. The results are shown in Table 2.

[0076] Impact resistance: The environmentally friendly high-toughness PE pipe obtained in the example was injection-molded, and the test was carried out with reference to the method of national standard GB / T 1843-2008 "Plastics - Determination of Izod impact strength". Before the test, the specimen was placed at a temperature of 23 °C and a relative humidity of 50% for debugging for 20 h. The notch type was A. There were 6 parallel groups, and the average value was taken. The results are shown in Table 2.

[0077] Table 2 Mechanical property test results Tensile strength (MPa) <![CDATA[Notched impact strength / kJ·m -2 > Example 1 33.4 19.4 Example 2 44.5 29.1 Example 3 45.1 30.4 Example 4 48.3 33.9 Example 5 39.7 25.5 Example 6 46.9 31.8 From the above results, it can be seen that the environmentally friendly high-toughness PE pipe prepared by the present invention has good aging resistance and very good mechanical properties. Specifically, by comparing Example 1 and Example 5, it can be seen that the use of modified carbon fiber has a better effect. The reason is that the modified carbon fiber can effectively improve the compatibility with the matrix, enabling the carbon fiber to be more effectively and uniformly dispersed in the matrix, thereby improving the mechanical properties of the pipe to a certain extent; further comparing Examples 2-4, the present invention preferably uses amino silane as 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane. The possible reason is that 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane contains two aminopropyl groups and one tetramethyldisiloxane, providing more reaction sites, which can form stronger chemical bonds with the hydroxyl groups (-OH) or carboxyl groups (-COOH) on the surface of the carbon fiber. And the tetramethyldisiloxane structure has high thermal stability and chemical stability, can maintain its performance during high-temperature processing and long-term use, is not easy to degrade, and shows significant advantages in toughening and anti-aging; on the contrary, 3-aminopropyldiisopropylethoxysilane and 3-[bis(2-hydroxyethyl)amino]propane-triethoxysilane contain ethoxy groups (-OCH 2 CH 3 ), or hydroxyethyl groups (-CH 2 CH 2The (OH) groups are prone to hydrolysis or oxidation under high temperature or humid environments, leading to the destruction of the molecular structure and affecting the stability of the material. Comparing Example 4 and Example 6, it can be seen that the butyric acid derivative used in Example 4 is 4-methylsulfonic acid butyrate. The possible reason is that 4-methylsulfonic acid butyrate, due to its strongly polar methylsulfonic acid group and high reactivity, can form stable amide bonds during the reaction and generate an antioxidant with excellent anti-aging performance. However, 4-chlorobutyric acid cannot achieve the same technical effect because the chlorine atom has low reactivity, is prone to side reactions, and the product has poor performance.

[0078] In summary, the anti-aging and toughening additive prepared by the present invention can effectively capture free radicals in the polymer degradation chain reaction and inhibit the oxidative degradation of the PE molecular chain to achieve anti-aging effects. The anti-aging and toughening additive can combine the carbon material and the organic anti-aging mechanism, combine the advantages of both, and have stable and efficient anti-aging performance. In addition, through grafting and compounding, an organic coating layer can be formed on the surface of the carbon material anti-aging filler, which can effectively improve the uniform dispersion of the carbon material anti-aging filler in the PE pipe, improve the chemical bonding between the carbon fiber and the PE matrix and the antioxidant, improve the interfacial bonding force, reduce stress concentration, and the introduced carbon material as a reinforcing phase can effectively absorb and disperse external stress, reduce the crack propagation of the PE matrix, and significantly improve the toughness, impact resistance and interfacial compatibility of the PE material. The antioxidant can capture free radicals, inhibit the oxidative degradation of the PE molecular chain, and inhibit the breakage of the PE molecular chain, further improving the toughness. Through chemical bonding and physical mixing, the anti-aging and toughening additive is uniformly dispersed in the PE matrix and plays a synergistic role. When applied to environmentally friendly high-toughness PE pipes, it can significantly improve the toughness and anti-aging performance of the PE pipes.

Claims

1. An environmentally friendly high-toughness PE pipe, characterized in that: The invention is composed of the following parts by weight: 40-70 parts by weight of pretreated PE waste material recycling material, 20-35 parts by weight of PE powder, 1-4 parts by weight of silicon dioxide, 3-6 parts by weight of talcum powder, 1-4 parts by weight of toughening agent, 2-6 parts by weight of compatibilizer, 3-7 parts by weight of dispersant, 1-3 parts by weight of lubricant and 4-8 parts by weight of anti-aging toughening additive; the anti-aging toughening additive is obtained by grafting reaction of silane-modified carbon fiber and anti-aging agent.

2. The environmentally friendly high-toughness PE pipe according to claim 1, characterized in that: The preparation method of the anti-aging toughening additive is as follows: Activating the carbon material to obtain a pretreated carbon material, taking 8-14 parts by weight of the pretreated carbon material and 150-300 parts by weight of an ethanol aqueous solution and mixing them by ultrasonication, and then adding 2-6 parts by weight of aminosilane and heating and stirring to obtain a silane-modified carbon material; Under a nitrogen environment, 4-8 parts by weight of a butyric acid derivative, 3-7 parts by weight of triethylamine and 20-30 parts by weight of 4-amino-2,6-di-tert-butylphenol are stirred and reacted to obtain an antioxidant; 8-12 parts by weight of the above silane-modified carbon material and 15-26 parts by weight of an antioxidant are stirred at room temperature, and then 0.5-2 parts by weight of N,N'-diisopropylcarbodiimide are added, and the mixture is stirred and reacted at 50-70°C and 400-800rpm for 3-6 hours to obtain an anti-aging toughening additive.

3. The environmentally friendly high-toughness PE pipe according to claim 2, characterized in that: The carbon material is any one of carbon fiber, single-walled carbon nanotube, multi-walled carbon nanotube and white carbon black.

4. The environmentally friendly high-toughness PE pipe according to claim 2, characterized in that: The aminosilane is at least one of 3-aminopropyldiisopropylethoxysilane and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane.

5. The environmentally friendly high-toughness PE pipe according to claim 2, characterized in that: The butyric acid derivative is one or any two of 4-methanesulfonylbutyric acid, 4-chlorobutyric acid and 4-bromobutyric acid.

6. The environmentally friendly high-toughness PE pipe according to claim 1, characterized in that: The toughening agent is at least one of diisononyl phthalate, ethylene-vinyl acetate copolymer, methyl methacrylate-butadiene-styrene, ethylene propylene diene monomer rubber, and styrene-butadiene.

7. The environmentally friendly high-toughness PE pipe according to claim 1, characterized in that: The compatibilizer is at least one of maleic anhydride grafted styrene and maleic anhydride grafted styrene and propylene.

8. The environmentally friendly high-toughness PE pipe according to claim 1, characterized in that: The dispersant is at least one of N,N'-ethylene bisstearamide, fatty alcohol polyoxyethylene ether sulfate, polyvinyl alcohol, calcium stearate, methyl amyl alcohol, and stearic acid monoglyceride.

9. The environmentally friendly high-toughness PE pipe according to claim 1, characterized in that: The lubricant is at least one of stearic acid, polypropylene wax and chlorinated paraffin.

10. A process for preparing the environmentally friendly high-toughness PE pipe according to any one of claims 1 to 9, characterized in that: The steps include: (1) crushing the recycled PE old material and sieving it to obtain a crushed raw material; washing the crushed raw material with a mixed solvent and drying it; heating and extruding the dried raw material with a co-melting extruder and cooling it to obtain a pre-treated recycled PE old material; (2) Weigh various raw materials according to weight ratio; take pre-treated PE waste material recycling material, PE powder, silicon dioxide, talcum powder, toughening agent, compatibilizer, dispersant, and lubricant and stir them in a mixer to obtain a mixed material; (3) The mixed material is put into a reactor, and after the temperature rises to 100-130°C, an anti-aging and toughening additive is added, and the temperature is continued to rise to 140-160°C and stirred for 20-500 minutes, and the material temperature is cooled and stirred until it reaches 50-700°C, and then added to a twin-screw extruder. Under the conditions that the melt temperature is set to an inlet temperature of 150-180°C, the extruder head is set to 220-260°C, and the screw speed is set to 120-260rpm, melt extrusion, plasticization, molding and granulation are carried out to obtain the environmentally friendly high-toughness PE pipe.