Impact-resistant PP-R pipe and preparation method thereof

Abstract

The invention discloses an impact-resistant PP-R pipe and a preparation method thereof, and relates to the field of plastic pipes. The impact-resistant PP-R pipe comprises the following raw materials in parts by weight: 73-85 parts of polypropylene random copolymer resin; 2-5 parts of modified zinc oxide whiskers; 8 to 12 parts of a hydrogenated styrene-butadiene-styrene block copolymer; 5-9 parts of toughening color master batch; 0.5-1 part of a light stabilizer; 0.7 to 1.2 parts of an antioxidant; wherein the toughening color master batch comprises the following raw materials: 80-86 parts of polypropylene random copolymer resin; 0.3 to 0.6 part of a nucleating agent; 5-10 parts of calcium carbonate; 2-4 parts of a dispersant; and 12-18 parts of a pigment. The PP-R pipe solves the problems of large low-temperature brittleness and large linear expansion coefficient of the PP-R pipe in the prior art.

Description

Technical Field

[0001] This invention relates to the field of plastic pipes, and in particular to an impact-resistant PP-R pipe and its preparation method. Background Technology

[0002] PP-R resin, or random copolymer polypropylene, is a random copolymer formed by copolymerizing propylene with another olefin monomer (or multiple olefin monomers). PP-R resin has the following advantages: good high-temperature creep resistance, a good combination of hardness and impact resistance, chemical corrosion resistance, low thermal conductivity, easy processing, and recyclability.

[0003] PP-R pipes are made from atactic polypropylene using a single-screw extruder with a mixing section and a dedicated extrusion die. PP-R pipes are hygienic, odorless, and offer excellent insulation and energy efficiency, making them widely used for transporting hot and cold water.

[0004] PP-R pipes, as the mainstream pipe material for both hot and cold water, suffer from low-temperature brittleness. In cold environments, they are prone to cracking when subjected to external physical impacts, leading to leaks during use. Furthermore, PP-R pipes have a high coefficient of linear expansion, which can easily cause deformation during installation and use, affecting their appearance and requiring improvement. Summary of the Invention

[0005] To address the issues of low-temperature brittleness and high coefficient of linear expansion in existing PP-R pipes, this application provides an impact-resistant PP-R pipe and its preparation method.

[0006] This application provides a PP-R pipe and its manufacturing method, which adopts the following technical solution: In a first aspect, this application discloses an impact-resistant PP-R pipe, comprising the following raw materials in parts by weight: 73-85 parts of random copolymer polypropylene resin; 2-5 parts of modified zinc oxide whiskers; 8-12 parts of hydrogenated styrene-butadiene-styrene block copolymer; 5-9 parts of toughening masterbatch; Light stabilizer 0.5-1 part; Antioxidant 0.7-1.2 parts; The toughening masterbatch includes the following raw materials: 80-86 parts of random copolymer polypropylene resin; 0.3-0.6 parts of nucleating agent; 5-10 parts of calcium carbonate; 2-4 parts of dispersant; and 12-18 parts of pigment.

[0007] By adopting the above technical solutions, hydrogenated styrene-butadiene-styrene block copolymer is added to the PP-R pipe to toughen the resin and improve its toughness in low-temperature environments. Simultaneously, the hydrogenated styrene-butadiene-styrene block copolymer has a saturated rubber phase, exhibiting good aging resistance. The addition of zinc oxide whiskers reduces the linear expansion coefficient of the pipe, enhancing its toughness. Furthermore, due to the whiskers themselves and the action of active oxygen, they possess certain antibacterial properties, further facilitating the transport of hot and cold water. Nucleating agents are added to the toughening masterbatch to increase the β-PP content in the polypropylene, effectively improving the pipe's impact resistance and heat distortion performance. The addition of calcium carbonate as a filler also contributes to toughening, improving low-temperature toughness, and enhancing the pipe's dimensional stability. By adding a compound of antioxidants and light stabilizers, both thermo-oxidative and photo-oxidative aging are combated, significantly extending the service life of the pipe under hot water transport conditions.

[0008] Optionally, the modified zinc oxide whiskers are prepared by the following steps: Pre-dry the zinc oxide whiskers at 100-120℃ for 2-3 hours to remove surface adsorbed water. Stearic acid, zinc ricinoleate, and ethanol are mixed and heated to 60-75°C. The mixture is then sonicated to completely dissolve the zinc stearate and zinc ricinoleate, resulting in a mixed solution. Zinc oxide whiskers were slowly added in batches to the mixture at 500-800 r / min. The mixture was stirred at 60-70℃ for 30-45 min. After cooling, the whiskers were filtered out, washed 2-3 times with ethanol, and then vacuum dried at 80-100℃ for 4-6 h. The mixture was then sieved to obtain modified zinc oxide whiskers.

[0009] By employing the above technical solution, zinc oxide whiskers are modified using a composite of stearic acid and zinc ricinoleate. Stearic acid anchors on the surface of the zinc oxide whiskers, forming a hydrophobic long-chain coating layer, which improves the oleophilicity of the zinc oxide whiskers and enhances their dispersion in the resin. The metal-oxygen / metal-hydroxyl interactions between zinc ricinoleate and the surface of the zinc oxide whiskers further improve their compatibility and lubrication with PP-R resin. This results in more uniform dispersion of the modified zinc oxide whiskers in the resin matrix, avoiding stress concentration and improving rigidity and thermal properties. Simultaneously, it exhibits low migration and does not affect antibacterial properties.

[0010] Optionally, the weight ratio of the zinc oxide whiskers, stearic acid, and zinc ricinoleate is 1:(5%-8%):(2%-4%).

[0011] By adopting the above technical solution, the amount of modifier used can be controlled to avoid the adverse effects of excessive lubrication on the toughness of the pipe, while ensuring that stearic acid does not have the risk of migration.

[0012] Optionally, the calcium carbonate is modified light calcium carbonate, prepared through the following steps: Weigh out light calcium carbonate, add deionized water to prepare a slurry with a mass fraction of 10%, heat to 80-85℃ and stir evenly, add phosphate ester accounting for 0.4%-0.7% of the mass of calcium carbonate and coconut oil accounting for 1%-3%, keep warm and stir for 2-3 hours, filter, dry, crush and sieve the obtained slurry to obtain modified light calcium carbonate.

[0013] By adopting the above technical solution, a composite modification of phosphate ester and coconut oil is selected. Phosphate ester has strong chemical bonding, playing a "coupling / anchoring" role and improving interfacial strength. Coconut oil provides long-chain alkyl groups, enhancing "compatibility / lubrication" with PP, improving processing flow and dispersion, and facilitating energy absorption at low temperatures. The modified light calcium carbonate has enhanced interfacial bonding with the matrix and more uniform dispersion, thus synergistically refining the crystal structure with the nucleating agent, significantly improving low-temperature impact strength, and better exerting its effect of reducing the coefficient of thermal expansion, reducing macroscopic dimensional changes.

[0014] Optionally, the melt index of the random copolymer polypropylene resin is 0.1-0.5 g / 10 min, 230℃ / 2.16 kg.

[0015] By adopting the above technical solution and selecting a special PP-R resin, the resulting pipe has better mechanical properties.

[0016] Optionally, the dispersant may be one or both of polyethylene wax and oxidized polyethylene wax.

[0017] Optionally, the antioxidant is a mixture of hindered phenolic antioxidant and phosphite antioxidant in a ratio of 1.2-1.5:1.

[0018] By adopting the above technical solutions and selecting compound antioxidants, the pipes have better resistance to thermal and oxidative aging, which is conducive to extending the service life of the pipes.

[0019] Optionally, the pigment may be one or more of phthalocyanine blue, phthalocyanine green, permanent orange, permanent red, toluidine red, titanium dioxide, and carbon black.

[0020] Optionally, the nucleating agent includes one or both of nucleating agent TMB-5 and nucleating agent WBG-II.

[0021] Secondly, this application discloses a method for preparing impact-resistant PP-R pipes, comprising the following steps: The raw materials for toughening masterbatch are mixed in a high-speed mixer and then extruded and sliced ​​using a twin-screw extruder to obtain toughening masterbatch. Toughened masterbatch, random copolymer polypropylene resin, modified zinc oxide whiskers, and hydrogenated styrene-butadiene-styrene block copolymer are placed in a mixer and stirred for 2-5 minutes to obtain a mixture. The mixture is extruded and granulated using a twin-screw extruder at 170-220℃ to obtain the mixed material; The mixed materials are extruded at 170-220℃ to obtain the impact-resistant PP-R pipe.

[0022] By adopting the above technical solution, toughened color masterbatch is first prepared, and then it is mixed and extruded with random copolymer polypropylene resin and other raw materials to obtain PP-R pipes that are resistant to low temperature and high impact, have a low expansion coefficient, are antibacterial and mildew resistant, and are resistant to aging.

[0023] In summary, this application has the following beneficial effects: 1. In PP-R pipes, hydrogenated styrene-butadiene-styrene block copolymer is added to toughen the resin and improve its toughness in low-temperature environments. This hydrogenated styrene-butadiene-styrene block copolymer also has a saturated rubber phase, resulting in good aging resistance. The addition of zinc oxide whiskers reduces the pipe's coefficient of linear expansion, further enhancing its toughness. Furthermore, due to the whiskers themselves and the action of active oxygen, they possess certain antibacterial properties, making them more suitable for hot and cold water transport. Nucleating agents are added to the toughening masterbatch to increase the β-PP content in the polypropylene, effectively improving the pipe's impact resistance and heat distortion properties. The addition of calcium carbonate as a filler also contributes to toughening, improving low-temperature toughness, and enhancing the pipe's dimensional stability. By adding a combination of antioxidants and light stabilizers, both thermo-oxidative and photo-oxidative aging are combated, significantly extending the pipe's service life under hot water transport conditions.

[0024] 2. A composite of stearic acid and zinc ricinoleate was used to modify zinc oxide whiskers. Stearic acid anchored on the surface of the zinc oxide whiskers, forming a hydrophobic long-chain coating layer, which improved the oleophilicity of the zinc oxide whiskers and enhanced their dispersion in the resin. Zinc ricinoleate interacted with the zinc oxide whisker surface via metal-oxygen / metal-hydroxyl groups, further improving compatibility and lubrication with PP-R resin. This resulted in more uniform dispersion of the modified zinc oxide whiskers in the resin matrix, avoiding stress concentration and improving rigidity and thermal properties. Simultaneously, low migration did not affect the antibacterial properties. Detailed Implementation

[0025] The present application will be further described in detail below with reference to various embodiments and comparative examples. Preparation Example

[0026] Preparation Example 1-1 Preparation of modified zinc oxide whiskers 1 kg of zinc oxide whiskers was pre-dried at 100°C for 2 hours to remove surface adsorbed water. Mix 50g stearic acid, 20g zinc ricinoleate and 300g solvent ethanol, heat to 60℃, and sonicate for 20min to completely dissolve zinc stearate and zinc ricinoleate to obtain a mixed solution. Zinc oxide whiskers were slowly added in batches to the mixture at 500 r / min. The mixture was stirred at 60°C for 30 min. After cooling, the whiskers were filtered out, washed three times with ethanol, and then vacuum dried at 80°C for 4 h. The mixture was then sieved to obtain modified zinc oxide whiskers.

[0027] Preparation Examples 1-2 Preparation of modified zinc oxide whiskers 1 kg of zinc oxide whiskers was pre-dried at 120°C for 3 hours to remove surface adsorbed water. Mix 80g stearic acid, 40g zinc ricinoleate and 500g solvent ethanol, heat to 75℃, and sonicate for 30min to completely dissolve zinc stearate and zinc ricinoleate to obtain a mixed solution. Zinc oxide whiskers were slowly added in batches to the mixture at 800 r / min. The mixture was stirred at 70°C for 45 min. After cooling, the whiskers were filtered out, washed twice with ethanol, and dried under vacuum at 100°C for 6 h. The mixture was then sieved to obtain modified zinc oxide whiskers.

[0028] Preparation Example 2-1 Preparation of modified light calcium carbonate Weigh 100g of light calcium carbonate with a mesh size of 1250, add 900g of deionized water to prepare a slurry with a mass fraction of 10%, heat to 80℃ and stir evenly, add 0.4g of phosphate ester and 1g of coconut oil, the phosphate ester is triethyl phenyl phosphate (TPP), keep warm and stir for 2h, filter, dry, crush and sieve the obtained slurry to obtain modified light calcium carbonate.

[0029] Preparation Example 2-2 Preparation of modified light calcium carbonate Weigh 100g of light calcium carbonate with a mesh size of 1250, add 900g of deionized water to prepare a slurry with a mass fraction of 10%, heat to 85℃ and stir evenly, add 0.7g of phosphate ester and 3g of coconut oil, the phosphate ester is trimethylsilane phosphate TMSP, keep warm and stir for 3h, filter, dry, crush and sieve the obtained slurry to obtain modified light calcium carbonate. Example

[0030] Example 1 An impact-resistant PP-R pipe, comprising the following raw materials: 73 kg of random copolymer polypropylene resin, using resin with a melt index of 0.1-0.5 g / 10 min and a temperature of 230℃ / 2.16 kg, specifically Sinopec Yanshan Petrochemical R4220 grade; 2 kg of modified zinc oxide whiskers, selected from the modified zinc oxide whiskers prepared in Preparation Example 1-1; 8 kg of hydrogenated styrene-butadiene-styrene block copolymer; Toughening masterbatch 5kg; Light stabilizer 0.5 kg, BASF 770; 0.7 kg of antioxidants were used, specifically 0.39 kg of hindered phenolic antioxidants and 0.31 kg of phosphite antioxidants. The hindered phenolic antioxidant was BASF Irganox 1076 and the phosphite antioxidant was BASF Irgafos 168. The toughening masterbatch specifically includes the following raw materials: 80 kg of random copolymer polypropylene resin, 0.3 kg of nucleating agent (TMB-5), 5 kg of calcium carbonate (light calcium carbonate with a particle size of 1250 mesh), 2 kg of dispersant, polyethylene wax, 12 kg of pigment (7 kg of phthalocyanine green and 5 kg of titanium dioxide).

[0031] A method for preparing impact-resistant PP-R pipe includes the following steps: The raw materials for toughening masterbatch are mixed in a high-speed mixer and then extruded and sliced ​​using a twin-screw extruder to obtain toughening masterbatch. Toughened masterbatch, random copolymer polypropylene resin, modified zinc oxide whiskers, and hydrogenated styrene-butadiene-styrene block copolymer are placed in a mixer and stirred for 2-5 minutes to obtain a mixture. The mixture was extruded and granulated using a twin-screw extruder to obtain a mixed material. The extrusion conditions were: conveying section temperature 90℃, melting section temperature 160℃, homogenization section temperature 200℃, die temperature 200℃, and screw speed 100 rpm. The mixed materials are extruded at 170-220℃ to obtain the impact-resistant PP-R pipe.

[0032] Example 2 An impact-resistant PP-R pipe, comprising the following raw materials: 85 kg of random copolymer polypropylene resin, using resin with a melt index of 0.1-0.5 g / 10 min and a temperature of 230℃ / 2.16 kg, specifically the Korean Hyosung R200P grade; 5 kg of modified zinc oxide whiskers, selected from the modified zinc oxide whiskers prepared in Preparation Examples 1-2; 12 kg of hydrogenated styrene-butadiene-styrene block copolymer; 9 kg of toughening masterbatch; 1 kg of light stabilizer, model Saab 119 (Italy); 1.2 kg of antioxidants were used, specifically 0.72 kg of hindered phenolic antioxidants and 0.48 kg of phosphite antioxidants. The hindered phenolic antioxidant was BASF Irganox 1010 and the phosphite antioxidant was ADKSTAB HP-10. The toughening masterbatch specifically includes the following raw materials: 86 kg of random copolymer polypropylene resin, 0.6 kg of nucleating agent (WBG-II), 10 kg of calcium carbonate (light calcium carbonate with a particle size of 1250 mesh), 4 kg of dispersant (oxidized polyethylene wax), 18 kg of pigment (10 kg of phthalocyanine blue and 8 kg of toluidine red).

[0033] The preparation method of PP-R pipe is the same as that in Example 1.

[0034] Example 3 An impact-resistant PP-R pipe, comprising the following raw materials: 79 kg of random copolymer polypropylene resin, using resin with a melt index of 0.1-0.5 g / 10 min and a temperature of 230℃ / 2.16 kg, specifically Sinopec Yanshan Petrochemical R4220 grade; 4 kg of modified zinc oxide whiskers, selected from the modified zinc oxide whiskers prepared in Preparation Examples 1-2; 10 kg of hydrogenated styrene-butadiene-styrene block copolymer; 7kg of toughening masterbatch; Light stabilizer 0.8 kg, BASF 770; 1.1 kg of antioxidants were used, specifically 0.62 kg of hindered phenolic antioxidants and 0.48 kg of phosphite antioxidants. The hindered phenolic antioxidant was BASF Irganox 1010 and the phosphite antioxidant was Sanleco 627. The toughening masterbatch specifically includes the following raw materials: 83 kg of random copolymer polypropylene resin, 0.5 kg of nucleating agent (selected from 0.3 kg of TMB-5 and 0.2 kg of WBG-II), 7 kg of calcium carbonate (selected from 1500 mesh light calcium carbonate), 3 kg of dispersant (selected from polyethylene wax), 16 kg of pigment (8 kg of phthalocyanine green), 5 kg of carbon black and 3 kg of toluidine red.

[0035] The preparation method of PP-R pipe is the same as that in Example 1.

[0036] Example 4 The difference between this embodiment and Embodiment 1 is that the calcium carbonate in the toughening masterbatch of the impact-resistant PP-R pipe raw material is different.

[0037] In this embodiment, the calcium carbonate in the toughening masterbatch is the modified light calcium carbonate obtained in Preparation Example 2-1.

[0038] Example 5 The difference between this embodiment and Embodiment 1 is that the calcium carbonate in the toughening masterbatch of the impact-resistant PP-R pipe raw material is different.

[0039] In this embodiment, the calcium carbonate in the toughening masterbatch is the modified light calcium carbonate obtained in Preparation Example 2-2. Comparative Example

[0040] Comparative Example 1 The difference between this comparative example and Example 1 is that the modified zinc oxide whiskers in the raw materials of the impact-resistant PP-R pipe are different.

[0041] In this comparative example, an equal amount of unmodified zinc oxide whiskers was used instead of the modified zinc oxide whiskers in Preparation Example 1-1.

[0042] Comparative Example 2 The difference between this comparative example and Example 1 is that the hydrogenated styrene-butadiene-styrene block copolymer in the raw material of the impact-resistant PP-R pipe is different.

[0043] In this comparative example, an equal amount of toughening agent polyolefin elastomer POE was used instead of hydrogenated styrene-butadiene-styrene block copolymer. Performance testing

[0044] The following performance tests were conducted on the PP-R pipes prepared for each embodiment and comparative example, and the test results are shown in Table 1.

[0045] Notched impact strength: The test was conducted in accordance with the method of GB / T 1043.1-2008 "Determination of impact properties of simply supported plastic beams - Part 1: Non-instrumental impact test". The specimen type was 1, the notch type was A, and the impact direction was lateral. The tests were conducted at room temperature and -20℃.

[0046] Coefficient of linear expansion: tested using thermomechanical analysis under a nitrogen atmosphere, with a test temperature range of -30 to 100℃.

[0047] Table 1 Sample <![CDATA[Izod impact strength (kJ / m 2 , 23 °C)]]> <![CDATA[Izod impact strength (kJ / m 2 , -20 °C)]]> <![CDATA[Coefficient of linear expansion (10 -5 m / m·°C)]]> Example 1 65 38 3.7 Example 2 64 38 3.5 Example 3 67 40 3.8 Example 4 71 45 3.2 Example 5 72 46 3.3 Comparative Example 1 52 20 5.1 Comparative Example 2 60 31 4.3 As shown in Table 1, the PP-R pipes prepared in this application exhibit good low-temperature toughness, and their notched impact strength can still reach 38-46 kJ / m in a cold environment of -20℃. 2 Furthermore, by adding fillers such as modified zinc oxide whiskers, the coefficient of linear expansion of PP-R pipes was reduced to 3.0-3.8×10⁻⁶. -5 The m / m·℃ makes it easier to install and use PP-R pipes.

[0048] Compared to Example 1, Examples 4-5 modified the calcium carbonate in the toughening masterbatch. The composite modification of phosphate ester and coconut oil allowed the toughening effect and the reduction of the expansion coefficient of calcium carbonate to be more fully exerted, thereby further improving the overall performance of PP-R pipes.

[0049] Compared to Example 1, Comparative Example 1 did not use stearic acid and zinc ricinoleate to modify the zinc oxide whiskers in the pipe raw material, resulting in uneven dispersion of the zinc oxide whiskers in the resin system and agglomeration, which led to stress concentration, affecting the impact strength and also adversely affecting the coefficient of linear expansion.

[0050] Compared to Example 1, Comparative Example 2 replaced the toughening agent in the pipe material with polyolefin elastomer POE. The data showed that the synergistic effect of hydrogenated styrene-butadiene-styrene block copolymer as toughening agent with modified zinc oxide whiskers and calcium carbonate was better, resulting in better overall performance of the pipe.

[0051] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An impact-resistant PP-R pipe, characterized in that, Including the following parts by weight of raw materials: 73-85 parts of random copolymer polypropylene resin; 2-5 parts of modified zinc oxide whiskers; 8-12 parts of hydrogenated styrene-butadiene-styrene block copolymer; 5-9 parts of toughening masterbatch; Light stabilizer 0.5-1 part; Antioxidant 0.7-1.2 parts; The toughening masterbatch includes the following raw materials: 80-86 parts of random copolymer polypropylene resin; 0.3-0.6 parts of nucleating agent; and 5-10 parts of calcium carbonate. Dispersant 2-4 parts; pigment 12-18 parts.

2. The impact-resistant PP-R pipe according to claim 1, characterized in that: The modified zinc oxide whiskers are prepared by the following steps: Pre-dry the zinc oxide whiskers at 100-120℃ for 2-3 hours to remove surface adsorbed water. Stearic acid, zinc ricinoleate, and ethanol are mixed and heated to 60-75°C. The mixture is then sonicated to completely dissolve the zinc stearate and zinc ricinoleate, resulting in a mixed solution. Zinc oxide whiskers were slowly added in batches to the mixture at 500-800 r / min. The mixture was stirred at 60-70℃ for 30-45 min. After cooling, the whiskers were filtered out, washed 2-3 times with ethanol, and then vacuum dried at 80-100℃ for 4-6 h. The mixture was then sieved to obtain modified zinc oxide whiskers.

3. The impact-resistant PP-R pipe according to claim 2, characterized in that: The weight ratio of zinc oxide whiskers, stearic acid, and zinc ricinoleate is 1:(5%-8%):(2%-4%).

4. The impact-resistant PP-R pipe according to claim 1, characterized in that: The calcium carbonate used is modified light calcium carbonate, which is prepared through the following steps: Weigh out light calcium carbonate, add deionized water to prepare a slurry with a mass fraction of 10%, heat to 80-85℃ and stir evenly, add phosphate ester accounting for 0.4%-0.7% of the mass of calcium carbonate and coconut oil accounting for 1%-3%, keep warm and stir for 2-3 hours, filter, dry, crush and sieve the obtained slurry to obtain modified light calcium carbonate.

5. The impact-resistant PP-R pipe according to claim 1, characterized in that: The random copolymer polypropylene resin has a melt index of 0.1-0.5 g / 10 min and a yield of 2.16 kg at 230 °C.

6. The impact-resistant PP-R pipe according to claim 1, characterized in that: The dispersant is selected from one or both of polyethylene wax and oxidized polyethylene wax.

7. The impact-resistant PP-R pipe according to claim 1, characterized in that: The antioxidant is a mixture of hindered phenolic antioxidant and phosphite antioxidant in a ratio of 1.2-1.5:

1.

8. The impact-resistant PP-R pipe according to claim 1, characterized in that: The pigment is selected from one or more of phthalocyanine blue, phthalocyanine green, permanent orange, permanent red, toluidine red, titanium dioxide, and carbon black.

9. The impact-resistant PP-R pipe according to claim 1, characterized in that: The nucleating agent includes one or both of nucleating agent TMB-5 and nucleating agent WBG-II.

10. A method for preparing an impact-resistant PP-R pipe according to any one of claims 1-9, characterized in that, Includes the following steps: The raw materials for toughening masterbatch are mixed in a high-speed mixer and then extruded and sliced ​​using a twin-screw extruder to obtain toughening masterbatch. Toughened masterbatch, random copolymer polypropylene resin, modified zinc oxide whiskers, and hydrogenated styrene-butadiene-styrene block copolymer are placed in a mixer and stirred for 2-5 minutes to obtain a mixture. The mixture is extruded and granulated using a twin-screw extruder at 170-220℃ to obtain the mixed material; The mixed materials are extruded at 170-220℃ to obtain the impact-resistant PP-R pipe.