Wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe and preparation method thereof

Abstract

The present application relates to the field of pipes, and specifically discloses a wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe and a preparation method. A wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe comprises an outer pipe layer, a steel pipe layer and an inner pipe layer, wherein the steel pipe layer is arranged between the outer pipe layer and the inner pipe layer, and the outer pipe layer is made of raw materials including the following parts by weight: 80-90 parts of polypropylene resin, 10-20 parts of polytetrafluoroethylene, and 1-3 parts; the inner pipe layer is made of raw materials including the following parts by weight: 70-80 parts of polypropylene resin and 10-20 parts of AS resin. A wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe of the present application has excellent wear resistance, impact resistance and corrosion resistance.

Description

Technical Field

[0001] The present application relates to the field of pipes, and more specifically, to a wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe and a preparation method thereof. Background Art

[0002] Steel-plastic composite pipe is an emerging composite pipe. It is based on seamless smooth pipe and welded steel pipe. The inner wall is coated with special coating. It is made through a series of processes. It retains the rigidity and strength of traditional metal pipes far exceeding plastic pipes and aluminum-plastic pipes. At the same time, it is light in weight, has mature installation technology, and good weather resistance. It is widely used in various fields such as oil, natural gas, and drainage pipes.

[0003] However, in actual use, steel-plastic composite pipes are prone to corrosion due to long-term transportation of industrial liquids in acid, alkali and salt environments. In addition, the outer wall of the steel-plastic composite pipe is easily worn by external impact, resulting in a short service life of the pipe, which requires frequent replacement and causes a waste of resources. Summary of the invention

[0004] In order to extend the service life of a steel-plastic composite pipe, the present application provides a wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe and a preparation method thereof.

[0005] In the first aspect, the present application provides a wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe, which adopts the following technical solution:

[0006] A wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe comprises an outer pipe layer, a steel pipe layer and an inner pipe layer, wherein the steel pipe layer is arranged between the outer pipe layer and the inner pipe layer, and the outer pipe layer is made of the following raw materials in parts by weight: 80-90 parts of polypropylene resin, 10-20 parts of polytetrafluoroethylene, and 1-3 parts of glycidyl methacrylate; the inner pipe layer is made of the following raw materials in parts by weight: 70-80 parts of polypropylene resin and 10-20 parts of AS resin.

[0007] By adopting the above technical solution, the steel-plastic composite pipe prepared from polypropylene resin has excellent corrosion resistance, anti-aging and impact resistance. By adding polytetrafluoroethylene to the polypropylene outer tube, the friction factor of polypropylene can be reduced, thereby improving the wear resistance of the polypropylene pipe. When polytetrafluoroethylene is blended with polypropylene, a film can be formed on the surface of polypropylene through Coulomb force and van der Waals force to protect the polypropylene, reduce the scratching and wear of the polypropylene film, and improve the service life of the polypropylene pipe.

[0008] At the same time, the oxygen-containing free radicals generated after the treatment of polytetrafluoroethylene can be grafted with the olefinic double bonds of glycidyl methacrylate to introduce epoxy groups on the surface of polytetrafluoroethylene, thereby improving the adhesion of polytetrafluoroethylene and promoting the adhesion between polytetrafluoroethylene and polypropylene. It not only improves the bonding strength of the molecules of the polypropylene pipe itself, but also enhances the bonding strength between the polypropylene pipe and the steel pipe, reducing the cracking and falling off of the pipe.

[0009] The combination of AS resin and polypropylene resin improves the corrosion resistance and weather resistance of polypropylene pipes. At the same time, AS resin has a certain entanglement effect with polypropylene, which refines the crystal size of polypropylene, thereby improving the toughness and impact strength of polypropylene pipes, reducing the cracking phenomenon of polypropylene pipes, and further improving the service life of polypropylene pipes.

[0010] Preferably, the outer tube layer raw material also includes 1-5 parts of polyethylene wax.

[0011] By adopting the above technical solution, adding polyethylene wax to polypropylene can reduce the friction coefficient of polypropylene, improve the wear resistance of polypropylene pipes, and reduce the scratches and wear of polypropylene pipes. Polyethylene wax can also improve the dispersion of each molecule in the polypropylene system. At the same time, polyethylene wax has good compatibility with polypropylene. When impacted, the polyethylene wax molecular chain breaks and absorbs part of the impact energy, which has a certain promoting effect on the impact resistance of polypropylene pipes.

[0012] Preferably, the inner tube layer raw material further includes 1-5 parts of a viscosity enhancer.

[0013] By adopting the above technical scheme, the thickener can enhance the bonding force between the polypropylene resin and the AS resin, and at the same time can promote better bonding of the polypropylene pipe to the steel pipe, improve the bonding force between the polypropylene pipe and the steel pipe, further improve the service life of the polypropylene steel-plastic composite pipe, and reduce the phenomenon of falling off and corrosion of the polypropylene pipe and the steel pipe.

[0014] Preferably, the tackifier is styrene-butadiene-styrene block copolymer.

[0015] By adopting the above technical solution, styrene-butadiene-styrene block copolymer is added to the polypropylene system, which, on the one hand, enhances the binding force between molecules in the polypropylene system, and on the other hand, styrene-butadiene-styrene block copolymer also improves the corrosion resistance of polypropylene pipes. At the same time, styrene-butadiene-styrene block copolymer can also improve the crystal structure of polypropylene, control the size of polypropylene spherulites, thereby improving the toughness of polypropylene pipes, and can also absorb part of the impact energy, reduce the brittleness and cracking of polypropylene pipes, and improve the service life of polypropylene composite pipes.

[0016] Preferably, the outer tube layer is made of the following raw materials in parts by weight: 82-87 parts of polypropylene resin, 13-17 parts of polytetrafluoroethylene, and 1.5-2.5 parts of glycidyl methacrylate; the inner tube layer is made of the following raw materials in parts by weight: 73-78 parts of polypropylene resin and 13-17 parts of AS resin.

[0017] By adopting the above technical solution and controlling the appropriate usage amount of the polypropylene pipe raw material, the various components of the polypropylene pipe can be better combined, thereby improving the wear resistance and corrosion resistance of the polypropylene pipe, and at the same time improving the impact resistance and toughness of the polypropylene pipe.

[0018] In a second aspect, the present application provides a method for preparing a wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe, which adopts the following technical solution:

[0019] A method for preparing a wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe comprises the following steps:

[0020] S1: After mixing polypropylene resin and AS resin, put them into an extruder to make a polypropylene inner tube layer, and then hot-melt compound the polypropylene inner tube with the steel tube;

[0021] S2: Preliminarily subject polytetrafluoroethylene to plasma treatment, then mix it with glycidyl methacrylate, heat it for reaction, and obtain glycidyl methacrylate modified polytetrafluoroethylene; then mix polypropylene resin and glycidyl methacrylate modified polytetrafluoroethylene, put them into an extruder for melt extrusion, and then coat it on the side of the steel pipe layer away from the polypropylene inner pipe, cool and shape it, obtain a polypropylene outer pipe layer, and finally obtain a polypropylene steel-plastic composite pipe.

[0022] Preferably, in step S2, the extrusion temperature of the extruder is 330-340°C.

[0023] By adopting the above technical solution, the prepared polypropylene steel-plastic composite pipe has excellent rigidity and strength, and polypropylene pipes with different properties are compounded on both sides of the steel pipe, so that the prepared polypropylene steel-plastic composite pipe has excellent corrosion resistance, wear resistance and toughness. Plasma treatment of polytetrafluoroethylene in advance can generate a large number of free radicals on the surface of polytetrafluoroethylene to form peroxides, which can be grafted and polymerized with the olefin-containing double bonds of glycidyl methacrylate when heated, thereby improving the adhesion of polytetrafluoroethylene, thereby improving the adhesion between polytetrafluoroethylene and polypropylene resin, and further promoting better bonding between polypropylene pipe and steel pipe.

[0024] Preferably, the heating reaction temperature of the polytetrafluoroethylene and glycidyl methacrylate is 70-80°C.

[0025] By adopting the above technical solution and controlling the appropriate temperature, the grafting reaction between polytetrafluoroethylene and glycidyl methacrylate is promoted to be better.

[0026] In summary, this application has the following beneficial effects:

[0027] 1. Since polytetrafluoroethylene and AS resin are added to the polypropylene system in this application, the wear resistance and corrosion resistance of the polypropylene pipe are improved by combining with polypropylene. Polytetrafluoroethylene can reduce the scratching and wear of the polypropylene film by forming a certain film on the polypropylene pipe, thereby increasing the service life of the polypropylene pipe. The entanglement of AS resin with the polypropylene molecular chain can improve the structure of polypropylene crystals, thereby increasing the toughness of polypropylene, reducing the brittleness and cracking of polypropylene, and further increasing the service life of the polypropylene pipe.

[0028] 2. The present application introduces epoxy groups on the surface of polytetrafluoroethylene by grafting glycidyl methacrylate with polytetrafluoroethylene, thereby improving the adhesion of polytetrafluoroethylene, enhancing the adhesion between polytetrafluoroethylene and polypropylene resin, and promoting better bonding between polypropylene pipe and steel pipe.

[0029] 3. This application maintains the excellent rigidity and strength of the steel-plastic pipe by compounding polypropylene pipes on both sides of the steel pipe, while also having excellent corrosion resistance, wear resistance and impact resistance. DETAILED DESCRIPTION

[0030] The present application is further described in detail below with reference to the embodiments.

[0031] Styrene-butadiene-styrene block copolymer was selected from Beijing Yanshan Branch of Sinopec, SBS1301.

[0032] The molecular weight of polyethylene wax is 3000.

[0033] The molecular weight of polytetrafluoroethylene is 40,000.

[0034] The molecular weight of polypropylene resin is 90,000.

[0035] The AS resin selected was Daqing Petrochemical Company of China National Petroleum Corporation (GF-5110).

[0036] TMA-3 was selected as the nucleating agent.

[0037] The antioxidant selected is phosphite.

[0038] The solvent is acetone.

[0039] Example

[0040] Example 1

[0041] The polypropylene steel-plastic composite pipe comprises an outer pipe layer, a steel pipe layer and an inner pipe layer. The steel pipe layer is composited between the outer pipe layer and the inner pipe layer. The outer pipe layer is made of the following raw materials in parts by weight: 85 kg of polypropylene resin for the outer pipe layer, 15 kg of polytetrafluoroethylene, 2 kg of glycidyl methacrylate, 2 kg of nucleating agent for the outer pipe layer, and 2 kg of antioxidant; the inner pipe layer is made of the following raw materials in parts by weight: 75 kg of polypropylene resin for the inner pipe layer, 15 kg of AS resin, and 2 kg of nucleating agent for the inner pipe layer.

[0042] The preparation method of polypropylene steel-plastic composite pipe comprises the following steps:

[0043] S1: After mixing the polypropylene resin, AS resin and nucleating agent for the inner tube layer, the mixture is put into a twin-screw extruder for extrusion granulation to obtain mixed particles, and then the mixed particles are put into a plastic pipe extruder for melt extrusion at a temperature of 200°C, cooled and shaped to obtain a polypropylene inner tube, and then the polypropylene inner tube is inserted into a steel pipe, and then the polypropylene inner tube and the steel pipe are hot-melt bonded to form a polypropylene inner tube layer on the inner side of the steel pipe, and the thickness of the polypropylene inner tube layer is 2mm±0.1mm, to obtain a polypropylene composite steel-plastic pipe semi-finished product;

[0044] S2: Plasma-treating polytetrafluoroethylene for 5 min, at a power of 50 W and an Ar atmosphere pressure of 50 Pa, then mixing the plasma-treated polytetrafluoroethylene with glycidyl methacrylate, heating at 75° C. for 24 h, then washing with a solvent and filtering the solid to obtain glycidyl methacrylate-modified polytetrafluoroethylene;

[0045] S3: After mixing the polypropylene resin for the outer tube layer, glycidyl methacrylate modified polytetrafluoroethylene, the nucleating agent and antioxidant for the outer tube layer, the mixture is put into a twin-screw extruder for extrusion granulation to obtain mixed particles, and then the mixed particles are put into a plastic pipe extruder for melt extrusion at a temperature of 330°C to evenly coat the outer surface of the steel pipe, and the outer tube layer of the polypropylene pipe is formed by cooling and shaping, and finally the polypropylene steel-plastic composite pipe is obtained. The thickness of the outer tube layer of the polypropylene pipe is 1.5mm±0.1mm.

[0046] Embodiment 2-5

[0047] The difference between Example 2-5 and Example 1 is that the content of each component in the polypropylene rigid-plastic composite pipe raw material is different, as shown in Table 1 for details.

[0048] Table 1: Content of each component in the raw materials of polypropylene rigid-plastic composite pipes

[0049]

[0050] Example 6

[0051] The difference between Example 6 and Example 1 is that the raw material of the outer tube layer of the polypropylene steel-plastic composite pipe further includes 3 kg of polyethylene wax, and the raw material of the inner tube layer further includes 3 kg of tackifier, wherein the tackifier is a commercially available tackifier Dofukate 371.

[0052] The preparation method of polypropylene steel-plastic composite pipe comprises the following steps:

[0053] S1: After mixing polypropylene resin, AS resin, tackifier and nucleating agent, put them into a twin-screw extruder for extrusion granulation to obtain mixed particles, then put the mixed particles into a plastic pipe extruder for melt extrusion at an extrusion temperature of 200°C, cool and shape to obtain a polypropylene inner tube, then insert the polypropylene inner tube into a steel pipe, and then hot-melt bond the polypropylene inner tube to the steel pipe to form a polypropylene inner tube layer on the inner side of the steel pipe, the thickness of the polypropylene inner tube layer is 2mm±0.1mm, and a polypropylene composite steel-plastic pipe semi-finished product is obtained;

[0054] S2: Plasma treatment of polytetrafluoroethylene for 5 min, with a treatment power of 50 W and an Ar atmosphere pressure of 50 Pa, then mixing the plasma-treated polytetrafluoroethylene with glycidyl methacrylate, heating at 75° C. for 24 h, then washing with a solvent and filtering the solid to obtain glycidyl methacrylate-modified polytetrafluoroethylene;

[0055] S3: After mixing polypropylene resin, glycidyl methacrylate modified polytetrafluoroethylene, polyethylene wax, nucleating agent and antioxidant, put them into a twin-screw extruder for extrusion granulation to obtain mixed particles, and then put the mixed particles into a plastic pipe extruder for melt extrusion at a temperature of 330°C to evenly coat the outer surface of the steel pipe, cool and shape to form a polypropylene pipe outer layer, and finally obtain a polypropylene steel-plastic composite pipe. The thickness of the polypropylene pipe outer layer is 1.5mm±0.1mm.

[0056] Example 7

[0057] The difference between Example 7 and Example 6 is that the amount of polyethylene wax used as the raw material for the outer tube layer of the polypropylene steel-plastic composite pipe is 5 kg, and the amount of viscosity enhancer used as the raw material for the inner tube layer is 5 kg.

[0058] Example 8

[0059] The difference between Example 8 and Example 6 is that the amount of polyethylene wax used as the raw material for the outer tube layer of the polypropylene steel-plastic composite pipe is 1 kg, and the amount of thickener used as the raw material for the inner tube layer is 1 kg.

[0060] Example 9

[0061] The difference between Example 9 and Example 6 is that the tackifier in the raw material of the inner tube layer of the polypropylene steel-plastic composite pipe is styrene-butadiene-styrene block copolymer.

[0062] Example 10

[0063] The difference between Example 10 and Example 6 is that the polyethylene wax in the raw material of the outer tube layer of the polypropylene steel-plastic composite pipe is replaced by an equal amount of commercially available lubricant, wherein the lubricant is butyl stearate.

[0064] Comparative Example

[0065] Comparative Example 1

[0066] The difference between Comparative Example 1 and Example 1 is that glycidyl methacrylate is not used in the raw material of the outer tube layer of the polypropylene steel-plastic composite pipe.

[0067] The preparation method of polypropylene steel-plastic composite pipe comprises the following steps:

[0068] S1: After mixing polypropylene resin and AS resin, put them into a twin-screw extruder for extrusion granulation to obtain mixed particles, then put the mixed particles into a plastic pipe extruder for melt extrusion at a temperature of 200°C, cool and shape to obtain a polypropylene inner tube, then insert the polypropylene inner tube into a steel pipe, and then hot-melt bond the polypropylene inner tube to the steel pipe to form a polypropylene inner tube layer on the inner side of the steel pipe, the thickness of the polypropylene inner tube layer is 2mm±0.1mm, and a polypropylene composite steel-plastic pipe semi-finished product is obtained;

[0069] S2: After mixing the polypropylene resin and polytetrafluoroethylene, put them into a twin-screw extruder for extrusion granulation to obtain mixed particles, and then put the mixed particles into a plastic pipe extruder for melt extrusion at a temperature of 330°C to evenly coat the outer surface of the steel pipe, cool and shape to form a polypropylene pipe outer layer, and finally obtain a polypropylene steel-plastic composite pipe. The thickness of the polypropylene pipe outer layer is 1.5mm±0.1mm.

[0070] The difference between Comparative Example 2 and Example 1 is that polytetrafluoroethylene and glycidyl methacrylate are not used in the raw materials of the outer tube layer of the polypropylene steel-plastic composite pipe.

[0071] The preparation method of polypropylene steel-plastic composite pipe comprises the following steps:

[0072] S1: After mixing polypropylene resin and AS resin, put them into a twin-screw extruder for extrusion granulation to obtain mixed particles, then put the mixed particles into a plastic pipe extruder for melt extrusion at a temperature of 200°C, cool and shape to obtain a polypropylene inner tube, then insert the polypropylene inner tube into a steel pipe, and then hot-melt bond the polypropylene inner tube to the steel pipe to form a polypropylene inner tube layer on the inner side of the steel pipe, the thickness of the polypropylene inner tube layer is 2mm±0.1mm, and a polypropylene composite steel-plastic pipe semi-finished product is obtained;

[0073] S2: Put the polypropylene resin into a twin-screw extruder for extrusion granulation to obtain mixed particles, then put the mixed particles into a plastic pipe extruder for melt extrusion at a temperature of 200°C, so that it is evenly coated on the outer surface of the steel pipe, cooled and shaped to form a polypropylene pipe outer layer, and finally a polypropylene steel-plastic composite pipe is obtained. The thickness of the polypropylene pipe outer layer is 1.5mm±0.1mm.

[0074] Comparative Example 3

[0075] The difference between Comparative Example 3 and Example 1 is that AS resin is not used in the raw material of the inner tube layer of the polypropylene steel-plastic composite pipe.

[0076] Comparative Example 4

[0077] The difference between Comparative Example 4 and Example 1 is that polytetrafluoroethylene and glycidyl methacrylate are not used in the raw material of the outer tube layer of the polypropylene steel-plastic composite pipe, and AS resin is not used in the raw material of the inner tube layer.

[0078] Comparative Example 5

[0079] The difference between Comparative Example 5 and Example 1 is that the amount of polytetrafluoroethylene used in the outer tube layer of the polypropylene steel-plastic composite pipe is 5 kg, and the amount of AS resin used in the raw material of the inner tube layer is 5 kg.

[0080] Performance testing

[0081] The following performance tests were conducted on the polypropylene steel-plastic composite pipes provided in Examples 1-10 and Comparative Examples 1-5 of the present application, and the test results are shown in Table 2.

[0082] Detection Methods

[0083] 1. Wear resistance

[0084] The wear resistance of polypropylene steel-plastic composite pipes was tested using the standard GB / T3960-2016 "Test method for sliding friction and wear of plastics".

[0085] 2. Impact resistance

[0086] GB / T14152-2001 "Test method for external impact resistance of thermoplastic plastic pipes - clockwise rotation method" is used to test the impact strength of polypropylene steel-plastic composite pipes.

[0087] 3. Corrosion resistance

[0088] Take a polypropylene inner tube sample, weigh the initial weight of the sample, then soak it in a sodium hydroxide solution containing 40% by mass, store it in a constant temperature and humidity chamber for 90 days, take out the sample and weigh it, and calculate the percentage of weight change before and after.

[0089] Table 2: Performance test data table

[0090]

[0091]

[0092] It can be seen from Examples 1-5 that the polypropylene steel-plastic composite pipe prepared in the present application has excellent wear resistance, impact resistance and corrosion resistance. The wear resistance and corrosion resistance of the polypropylene pipe are improved by combining polytetrafluoroethylene and AS resin with polypropylene respectively, while improving the crystal structure of polypropylene, and improving the toughness and impact resistance of the polypropylene pipe. At the same time, polytetrafluoroethylene and glycidyl methacrylate are grafted and polymerized to improve the adhesion of polytetrafluoroethylene, promote better bonding between polytetrafluoroethylene and polypropylene, and enhance the bonding force between the polypropylene pipe and the steel pipe. The contents of each component in the raw materials of the polypropylene steel-plastic composite pipe in Examples 1-5 are different, and Example 1 is the optimal example.

[0093] In Examples 6-8, polyethylene wax is added to the polypropylene outer tube layer to reduce the friction coefficient of the polypropylene tube, reduce scratches and friction, and thus improve the wear resistance of the polypropylene tube. At the same time, polyethylene wax can improve the dispersibility of each molecule in the polypropylene resin system, and polyethylene wax can also promote the impact resistance of the polypropylene tube to a certain extent. In Example 10, other compounds are used instead of polyethylene wax. From the test results, it can be seen that the performance of polyethylene wax is better.

[0094] At the same time, in Examples 6-8, adding a thickener to the polypropylene inner tube layer can not only promote the bonding strength between polypropylene and AS resin, but also promote better bonding between the polypropylene tube and the steel tube, reduce the polypropylene tube from easily falling off from the steel tube, and be corroded, thereby further improving the service life of the polypropylene tube.

[0095] In Example 9, the tackifier in the raw material of the polypropylene inner tube layer uses styrene-butadiene-styrene block copolymer, which improves the bonding force and corrosion resistance between the molecules of the polypropylene resin system on the one hand. On the other hand, styrene-butadiene-styrene block copolymer can improve the crystal structure of polypropylene, improve the toughness of the polypropylene pipe, reduce the cracking and corrosion of the polypropylene pipe. At the same time, styrene-butadiene-styrene block copolymer can also absorb part of the impact performance, thereby improving the impact resistance of the polypropylene pipe and further improving the service life of the polypropylene pipe. From the test results, it can be seen that compared with Example 6, the corrosion resistance of the polypropylene pipe in Example 9 is better.

[0096] It can be seen from Comparative Examples 1, 2 and 3 that when preparing the polypropylene composite pipe, if any component is missing from polytetrafluoroethylene, glycidyl methacrylate and AS resin, the performance of the polypropylene composite pipe will decrease. In Comparative Example 2, glycidyl methacrylate is not used, and the wear resistance of the polypropylene pipe is greatly affected, which further illustrates that the grafting effect of glycidyl methacrylate and polytetrafluoroethylene improves the bonding strength between polytetrafluoroethylene and polypropylene.

[0097] The performance of the polypropylene composite pipe in Comparative Example 4 is the worst, indicating that the wear resistance and corrosion resistance of ordinary polypropylene pipes are limited, which will affect the service life of the polypropylene pipes.

[0098] In Comparative Example 5, the amounts of polytetrafluoroethylene and AS resin used are different. From the test results, it can be seen that the wear resistance and corrosion resistance of the polypropylene pipe are limitedly improved, indicating that the use of too little polytetrafluoroethylene and AS resin will affect the promotion of the wear resistance and corrosion resistance of the polypropylene pipe.

[0099] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe, characterized in that: The invention comprises an outer tube layer, a steel tube layer and an inner tube layer, wherein the steel tube layer is arranged between the outer tube layer and the inner tube layer, the outer tube layer is made of the following raw materials in parts by weight: 80-90 parts of polypropylene resin, 10-20 parts of polytetrafluoroethylene and 1-3 parts of glycidyl methacrylate; the inner tube layer is made of the following raw materials in parts by weight: 70-80 parts of polypropylene resin and 10-20 parts of AS resin; the polytetrafluoroethylene is subjected to plasma treatment in advance, and then mixed with glycidyl methacrylate and heated for reaction to obtain glycidyl methacrylate modified polytetrafluoroethylene.

2. The wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe according to claim 1, characterized in that: The outer tube layer raw material also includes 1-5 parts of polyethylene wax.

3. The wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe according to claim 1, characterized in that: The inner tube layer raw material also includes 1-5 parts of a tackifier.

4. The wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe according to claim 3, characterized in that: The tackifier is styrene-butadiene-styrene block copolymer.

5. The wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe according to claim 1, characterized in that: The outer tube layer is made of the following raw materials in parts by weight: 82-87 parts of polypropylene resin, 13-17 parts of polytetrafluoroethylene, and 1.5-2.5 parts of glycidyl methacrylate; the inner tube layer is made of the following raw materials in parts by weight: 73-78 parts of polypropylene resin and 13-17 parts of AS resin.

6. A method for preparing a wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: After mixing polypropylene resin and AS resin, put them into an extruder to make a polypropylene inner tube layer, and then hot-melt compound the polypropylene inner tube with the steel tube; S2: Preliminarily subject polytetrafluoroethylene to plasma treatment, then mix it with glycidyl methacrylate, heat it for reaction, and obtain glycidyl methacrylate modified polytetrafluoroethylene; then mix polypropylene resin and glycidyl methacrylate modified polytetrafluoroethylene, put them into an extruder for melt extrusion, and then coat it on the side of the steel pipe layer away from the polypropylene inner pipe, cool and shape it, obtain a polypropylene outer pipe layer, and finally obtain a polypropylene steel-plastic composite pipe.

7. A method for preparing a wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe according to claim 6, characterized in that: In step S2, the extrusion temperature of the extruder is 330-340°C.

8. The method for preparing a wear-resistant and corrosion-resistant polypropylene steel-plastic composite pipe according to claim 6, characterized in that: The heating reaction temperature of the polytetrafluoroethylene and glycidyl methacrylate is 70-80°C.

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