HDPE hollow wall plastic steel winding pipe

Abstract

The invention relates to the technical field of pipes, in particular to an HDPE hollow wall plastic steel winding pipe. The preparation process of the HDPE hollow wall plastic steel winding pipe comprises the following steps: (1) extruding the inner pipe; (2) spiral winding; (3) treating the steel belt; (4) winding a steel belt; (5) extruding an outer pipe; the inner tube is prepared from the following raw materials: high-density polyethylene, polypropylene, dicumyl peroxide, a modifier, pentaerythritol stearate and an antioxidant, and the modifier is sodium polyacrylate modified glass fiber. The HDPE hollow wall plastic steel winding pipe provided by the invention is particularly suitable for high-load underground pipeline systems, such as urban drainage and industrial conveying pipelines.

Description

Technical Field

[0001] The invention relates to the technical field of pipes, in particular to a HDPE hollow wall plastic-steel winding pipe. Background Art

[0002] In the construction of modern infrastructure, pipeline systems, as important transmission and distribution media, are widely used in urban water supply and drainage, sewage treatment, industrial wastewater discharge and other fields. Among them, hollow wall wound pipes have become one of the main choices in the market due to their light weight, high strength, easy installation, corrosion resistance and other characteristics. However, with the continuous improvement of engineering application requirements, some performance indicators of traditional hollow wall wound pipes are gradually difficult to meet the emerging high load, long life and reliability requirements. Traditional hollow wall wound pipes are usually based on pure plastic materials. Although they have good chemical corrosion resistance and light weight, under high load or extreme environmental conditions, the problems of low ring stiffness and impact performance begin to limit their application scope. Especially in situations where large traffic loads are carried or structural integrity needs to be maintained for a long time, these pipes are prone to deformation, collapse and other phenomena.

[0003] In recent years, HDPE (high-density polyethylene) hollow wall plastic-steel spiral pipe has attracted widespread attention because it combines the excellent properties of plastic and steel. HDPE material is known for its excellent toughness and impact resistance, while the addition of steel significantly improves the strength and pressure resistance of the pipe. Through optimized structural design and material selection, this pipe has shown excellent performance advantages in a variety of application environments. However, due to the weak bonding between steel and HDPE, long-term use may cause the two to separate and form gaps, which significantly reduces the durability of the pipe. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a HDPE hollow wall plastic-steel wrapped pipe to improve the ring stiffness and durability of the HDPE hollow wall plastic-steel wrapped pipe.

[0005] Based on the above purpose, the present invention provides a preparation process of a HDPE hollow wall plastic-steel wound pipe, which is characterized by comprising the following steps:

[0006] (1) Inner tube extrusion: weigh the inner tube raw material to prepare a mixed material, and then extrude it through an extruder to form a hollow rectangular tube, which is the inner tube;

[0007] (2) Spiral winding: The extruded inner tube is placed on a winding machine for winding, and hot air is used during the winding process to fuse and connect the wound tubes to obtain a wound inner tube;

[0008] (3) Steel strip treatment: The steel strip is immersed in a phosphoric acid aqueous solution for phosphating treatment to obtain a surface treated steel strip;

[0009] (4) Steel strip winding: The surface treated steel strip is wound around the outer wall of the winding inner tube to obtain a steel strip wound tube;

[0010] (5) Extrusion of outer tube: Weigh the outer tube raw materials to prepare a mixed material, extrude it through an extruder, wrap it on the outer surface of the steel belt winding tube, and then cool and cut it to obtain a HDPE hollow wall plastic steel winding tube.

[0011] Furthermore, in step (1), the inner tube raw materials include, by weight: 40-60 parts of high-density polyethylene, 4-6 parts of polypropylene, 0.3-0.7 parts of dicumyl peroxide, 1-5 parts of modifier, 1.5-2.5 parts of pentaerythritol stearate and 0.5-2 parts of antioxidant.

[0012] Furthermore, the outer tube raw material in step (5) comprises, by weight: 40-60 parts of high-density polyethylene, 1.5-2.5 parts of pentaerythritol stearate and 0.5-2 parts of antioxidant.

[0013] Furthermore, the preparation method of the modifier is as follows: add glass fiber to deionized water, stir evenly, then add a 2g / L sodium acrylate aqueous solution, stir at 30-40°C for 25-35min under a nitrogen atmosphere, then dropwise add a 0.02g / mL cerium ammonium nitrate aqueous solution, react at 30-40°C for 2.5-3.5h, after the reaction is completed, wash and filter, vacuum dry, and finally grind through a 100-mesh sieve to obtain a modifier.

[0014] Preferably, the usage ratio of the glass fiber, deionized water, sodium acrylate aqueous solution and cerium ammonium nitrate aqueous solution is 3g:100mL:20mL:20mL.

[0015] Preferably, in step (1), the extrusion temperature of the extruder is 220-230° C., the screw speed is 40-60 rpm, and the extrusion pressure is 8-12 MPa.

[0016] Preferably, the dimensions of the inner tube in step (1) are: diameter 200-400 mm, wall thickness 2-4 mm.

[0017] Preferably, in step (2), the winding angle is 30-45 degrees and the winding speed is 0.5-2 m / min.

[0018] Preferably, the thickness of the steel strip in step (3) is 0.5 mm.

[0019] Preferably, the concentration of the phosphoric acid aqueous solution in step (3) is 8-15 wt %, the phosphating time is 8-12 min, and the temperature is 70-80° C.

[0020] Preferably, in step (4), the winding angle is 30-45 degrees and the winding speed is 0.5-2 m / min.

[0021] Preferably, in step (5), the extrusion temperature of the extruder is 220-230° C., the screw speed is 40-60 rpm, and the extrusion pressure is 8-12 MPa.

[0022] Furthermore, the present invention also provides a HDPE hollow wall plastic-steel wrapped pipe, which is obtained by the preparation process of the above HDPE hollow wall plastic-steel wrapped pipe.

[0023] Beneficial effects of the present invention:

[0024] The present invention greatly improves the ring stiffness of the pipe by introducing modifiers and steel strip surface treatment technology, and has excellent stability and long service life under high temperature conditions, making it very suitable for high temperature operations and extreme environment applications.

[0025] The invention adopts glass fiber modified by sodium polyacrylate as a modifier, and due to the reinforcing effect of the glass fiber and the cross-linking effect of the sodium polyacrylate on the surface of the glass fiber, the ring stiffness and durability of the pipe are effectively improved.

[0026] The present invention adopts phosphoric acid treatment technology to increase the surface roughness of the steel belt and form phosphate, which greatly enhances the bonding force between the steel belt and the polyethylene layer containing the modifier, avoids the separation problem after long-term use, and improves the overall durability.

[0027] The HDPE hollow wall plastic-steel winding pipe provided by the present invention is particularly suitable for high-load underground pipeline systems, such as urban drainage, industrial transportation pipelines, etc., and gives full play to its enhanced physical properties and durability. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0029] The average diameter of the glass fiber in the specific embodiment of the present invention is 25 μm, and the average length is 2.2 mm; the melt index of high-density polyethylene is 0.45 g / 10 min (190° C., 2.16 kg), and the melt index of polypropylene is 0.36 g / 10 min (230° C., 2.16 kg).

[0030] Preparation example: Add 3g of glass fiber to 100mL of deionized water, stir evenly, then add 20mL of 2g / L sodium acrylate aqueous solution, stir at 35°C for 30min under nitrogen atmosphere, then add 20mL of 0.02g / mL cerium ammonium nitrate aqueous solution dropwise, react at 35°C for 3h, after the reaction is completed, wash and filter, vacuum dry, and finally grind through a 100-mesh sieve to obtain a modifier.

[0031] Embodiment 1:

[0032] (1) Inner tube extrusion: 50 parts of high-density polyethylene, 5 parts of polypropylene, 0.5 parts of dicumyl peroxide, 3 parts of the modifier prepared in the preparation example, 2 parts of pentaerythritol stearate and 1 part of antioxidant 1010 were mixed by weight to prepare a mixed material, which was then put into an extruder. The extrusion temperature was set to 220° C., the screw speed was set to 50 rpm, and the extrusion pressure was set to 10 MPa. The extruder was started and extruded through a spiral die to form a hollow rectangular tube, i.e., the inner tube. The dimensions of the inner tube were: diameter 300 and wall thickness 3 mm;

[0033] (2) Spiral winding: Place the extruded inner tube on the winding machine, adjust the winding angle to 45 degrees, start the winding machine, set the winding speed to 1 m / min, and use hot air to fuse and connect the wound tubes during the winding process to obtain a wound inner tube;

[0034] (3) Steel strip treatment: The steel strip with a thickness of 0.5 mm was then immersed in a 10 wt % phosphoric acid aqueous solution for phosphating treatment. The treatment time was 10 min at a temperature of 75° C. to obtain a surface treated steel strip.

[0035] (4) Steel strip winding: Wrap the surface treated steel strip on the outer wall of the winding inner tube, set the winding angle to 45 degrees, start the winding machine, set the winding speed to 1m / min, and wind 3 turns to obtain a steel strip wound tube;

[0036] (5) Extrusion of outer tube: 50 parts of high-density polyethylene, 2 parts of pentaerythritol stearate and 1 part of antioxidant 1010 were mixed by weight to obtain a mixture, which was then put into an extruder. The temperature was set to 220°C, the screw speed was 50 rpm, and the extrusion pressure was 10 MPa. The extruder was started, and the extruded material was wrapped on the outer surface of the steel strip winding tube with a wrapping thickness of 3 mm. The mixture was then cooled and cut to obtain a HDPE hollow wall plastic steel winding tube.

[0037] Embodiment 2:

[0038] (1) Inner tube extrusion: 40 parts of high-density polyethylene, 4 parts of polypropylene, 0.3 parts of dicumyl peroxide, 1 part of the modifier prepared in the preparation example, 1.5 parts of pentaerythritol stearate and 0.5 parts of antioxidant 1010 were mixed by weight to prepare a mixed material, which was then put into an extruder. The extrusion temperature was set to 220° C., the screw speed was set to 40 rpm, and the extrusion pressure was set to 8 MPa. The extruder was started and extruded through a spiral die to form a hollow rectangular tube, i.e., the inner tube. The dimensions of the inner tube were: diameter 200 and wall thickness 2 mm;

[0039] (2) Spiral winding: Place the extruded inner tube on the winding machine, adjust the winding angle to 30 degrees, start the winding machine, set the winding speed to 0.5 m / min, and use hot air to fuse and connect the wound tubes during the winding process to obtain a wound inner tube;

[0040] (3) Steel strip treatment: The steel strip with a thickness of 0.5 mm was then immersed in a phosphoric acid aqueous solution with a concentration of 8 wt % for phosphating treatment. The treatment time was 12 min and the temperature was 70° C. to obtain a surface-treated steel strip.

[0041] (4) Steel strip winding: Wrap the surface treated steel strip on the outer wall of the winding inner tube, set the winding angle to 30 degrees, start the winding machine, set the winding speed to 0.5 m / min, and wind 3 turns to obtain a steel strip wound tube;

[0042] (5) Extrusion of outer tube: 40 parts of high-density polyethylene, 1.5 parts of pentaerythritol stearate and 0.5 parts of antioxidant 1010 were mixed by weight to obtain a mixture, which was then put into an extruder. The temperature was set to 220°C, the screw speed was 40 rpm, and the extrusion pressure was 8 MPa. The extruder was started, and the extruded material was wrapped on the outer surface of the steel strip wrapped tube with a wrapping thickness of 2 mm. The mixture was then cooled and cut to obtain a HDPE hollow wall plastic steel wrapped tube.

[0043] Embodiment 3:

[0044] (1) Inner tube extrusion: 60 parts of high-density polyethylene, 6 parts of polypropylene, 0.7 parts of diisopropylbenzene peroxide, 5 parts of the modifier prepared in the preparation example, 2.5 parts of pentaerythritol stearate and 2 parts of antioxidant 1010 were mixed by weight to prepare a mixed material, which was then put into an extruder. The extrusion temperature was set to 230° C., the screw speed was set to 60 rpm, and the extrusion pressure was set to 12 MPa. The extruder was started and extruded through a spiral die to form a hollow rectangular tube, i.e., the inner tube. The dimensions of the inner tube were: diameter 400 and wall thickness 4 mm;

[0045] (2) Spiral winding: Place the extruded inner tube on the winding machine, adjust the winding angle to 45 degrees, start the winding machine, set the winding speed to 2 m / min, and use hot air to fuse and connect the wound tubes during the winding process to obtain a wound inner tube;

[0046] (3) Steel strip treatment: The steel strip with a thickness of 0.5 mm was then immersed in a 15 wt % phosphoric acid aqueous solution for phosphating treatment at a temperature of 80° C. for 8 min to obtain a surface treated steel strip.

[0047] (4) Steel strip winding: Wrap the surface treated steel strip on the outer wall of the winding inner tube, set the winding angle to 45 degrees, start the winding machine, set the winding speed to 2m / min, and wind 3 turns to obtain a steel strip wound tube;

[0048] (5) Extrusion of outer tube: 60 parts of high-density polyethylene, 2.5 parts of pentaerythritol stearate and 2 parts of antioxidant 1010 were mixed by weight to obtain a mixture, which was then put into an extruder. The temperature was set to 230°C, the screw speed was set to 60 rpm, and the extrusion pressure was set to 12 MPa. The extruder was started, and the extruded material was wrapped on the outer surface of the steel strip wrapped tube with a wrapping thickness of 4 mm. The mixture was then cooled and cut to obtain a HDPE hollow wall plastic steel wrapped tube.

[0049] Comparative Example 1:

[0050] The difference between Comparative Example 1 and Example 1 is that no modifier is added to the inner tube raw material;

[0051] The specific preparation steps are as follows:

[0052] (1) Inner tube extrusion: 50 parts of high-density polyethylene, 5 parts of polypropylene, 0.5 parts of dicumyl peroxide, 2 parts of pentaerythritol stearate and 1 part of antioxidant 1010 were mixed by weight to prepare a mixed material, which was then put into an extruder. The extrusion temperature was set to 220° C., the screw speed was set to 50 rpm, and the extrusion pressure was set to 10 MPa. The extruder was started and extruded through a spiral die to form a hollow rectangular tube, i.e., the inner tube. The dimensions of the inner tube were: diameter 300 and wall thickness 3 mm;

[0053] (2) Spiral winding: Place the extruded inner tube on the winding machine, adjust the winding angle to 45 degrees, start the winding machine, set the winding speed to 1 m / min, and use hot air to fuse and connect the wound tubes during the winding process to obtain a wound inner tube;

[0054] (3) Steel strip treatment: The steel strip with a thickness of 0.5 mm was then immersed in a 10 wt % phosphoric acid aqueous solution for phosphating treatment. The treatment time was 10 min at a temperature of 75° C. to obtain a surface treated steel strip.

[0055] (4) Steel strip winding: Wrap the surface treated steel strip on the outer wall of the winding inner tube, set the winding angle to 45 degrees, start the winding machine, set the winding speed to 1m / min, and wind 3 turns to obtain a steel strip wound tube;

[0056] (5) Extrusion of outer tube: 50 parts of high-density polyethylene, 2 parts of pentaerythritol stearate and 1 part of antioxidant 1010 were mixed by weight to obtain a mixture, which was then put into an extruder. The temperature was set to 220°C, the screw speed was set to 50 rpm, and the extrusion pressure was set to 10 MPa. The extruder was started, and the extruded material was wrapped on the outer surface of the steel strip winding tube with a wrapping thickness of 3 mm. The mixture was then cooled and cut to obtain a winding tube.

[0057] Comparative Example 2:

[0058] The difference between Comparative Example 2 and Example 1 is that: the steel strip is not surface treated;

[0059] The specific preparation steps are as follows:

[0060] (1) Inner tube extrusion: 50 parts of high-density polyethylene, 5 parts of polypropylene, 0.5 parts of dicumyl peroxide, 3 parts of the modifier prepared in the preparation example, 2 parts of pentaerythritol stearate and 1 part of antioxidant 1010 were mixed by weight to prepare a mixed material, which was then put into an extruder. The extrusion temperature was set to 220° C., the screw speed was set to 50 rpm, and the extrusion pressure was set to 10 MPa. The extruder was started and extruded through a spiral die to form a hollow rectangular tube, i.e., the inner tube. The dimensions of the inner tube were: diameter 300 and wall thickness 3 mm;

[0061] (2) Spiral winding: Place the extruded inner tube on the winding machine, adjust the winding angle to 45 degrees, start the winding machine, set the winding speed to 1 m / min, and use hot air to fuse and connect the wound tubes during the winding process to obtain a wound inner tube;

[0062] (3) Steel strip winding: Wrap a steel strip with a thickness of 0.5 mm on the outer wall of the winding inner tube, set the winding angle to 45 degrees, start the winding machine, set the winding speed to 1 m / min, and wind 3 turns to obtain a steel strip wound tube;

[0063] (4) Extrusion of outer tube: 50 parts of high-density polyethylene, 2 parts of pentaerythritol stearate and 1 part of antioxidant 1010 were mixed by weight to obtain a mixture, which was then put into an extruder. The temperature was set to 220°C, the screw speed was set to 50 rpm, and the extrusion pressure was set to 10 MPa. The extruder was started, and the extruded material was wrapped on the outer surface of the steel strip winding tube with a wrapping thickness of 3 mm. The mixture was then cooled and cut to obtain a winding tube.

[0064] Comparative Example 3:

[0065] The difference between Comparative Example 3 and Example 1 is that the modifier is replaced by glass fiber;

[0066] The specific steps are as follows:

[0067] (1) Inner tube extrusion: 50 parts of high-density polyethylene, 5 parts of polypropylene, 0.5 parts of dicumyl peroxide, 3 parts of glass fiber, 2 parts of pentaerythritol stearate and 1 part of antioxidant 1010 were mixed by weight to prepare a mixture, which was then put into an extruder. The extrusion temperature was set to 220° C., the screw speed was set to 50 rpm, and the extrusion pressure was set to 10 MPa. The extruder was started and extruded through a spiral die to form a hollow rectangular tube, i.e., the inner tube. The dimensions of the inner tube were: diameter 300 and wall thickness 3 mm;

[0068] (2) Spiral winding: Place the extruded inner tube on the winding machine, adjust the winding angle to 45 degrees, start the winding machine, set the winding speed to 1 m / min, and use hot air to fuse and connect the wound tubes during the winding process to obtain a wound inner tube;

[0069] (3) Steel strip treatment: The steel strip with a thickness of 0.5 mm was then immersed in a 10 wt % phosphoric acid aqueous solution for phosphating treatment. The treatment time was 10 min at a temperature of 75° C. to obtain a surface treated steel strip.

[0070] (4) Steel strip winding: Wrap the surface treated steel strip on the outer wall of the winding inner tube, set the winding angle to 45 degrees, start the winding machine, set the winding speed to 1m / min, and wind 3 turns to obtain a steel strip wound tube;

[0071] (5) Extrusion of outer tube: 50 parts of high-density polyethylene, 2 parts of pentaerythritol stearate and 1 part of antioxidant 1010 were mixed by weight to obtain a mixture, which was then put into an extruder. The temperature was set to 220°C, the screw speed was set to 50 rpm, and the extrusion pressure was set to 10 MPa. The extruder was started, and the extruded material was wrapped on the outer surface of the steel strip winding tube with a wrapping thickness of 3 mm. The mixture was then cooled and cut to obtain a winding tube.

[0072] Comparative Example 4:

[0073] The difference between Comparative Example 4 and Example 1 is that the steel strip is not wound;

[0074] The specific steps are as follows:

[0075] (1) Inner tube extrusion: 50 parts of high-density polyethylene, 5 parts of polypropylene, 0.5 parts of dicumyl peroxide, 3 parts of the modifier prepared in the preparation example, 2 parts of pentaerythritol stearate and 1 part of antioxidant 1010 were mixed by weight to prepare a mixed material, which was then put into an extruder. The extrusion temperature was set to 220° C., the screw speed was set to 50 rpm, and the extrusion pressure was set to 10 MPa. The extruder was started and extruded through a spiral die to form a hollow rectangular tube, i.e., the inner tube. The dimensions of the inner tube were: diameter 300 and wall thickness 3 mm;

[0076] (2) Spiral winding: Place the extruded inner tube on the winding machine, adjust the winding angle to 45 degrees, start the winding machine, set the winding speed to 1 m / min, and use hot air to fuse and connect the wound tubes during the winding process to obtain a wound inner tube;

[0077] (3) Extrusion of outer tube: 50 parts of high-density polyethylene, 2 parts of pentaerythritol stearate and 1 part of antioxidant 1010 were mixed by weight to obtain a mixture, which was then put into an extruder. The temperature was set to 220°C, the screw speed was 50 rpm, and the extrusion pressure was 10 MPa. The extruder was started, and the extruded material was wrapped around the outer surface of the wrapped inner tube with a wrapping thickness of 3 mm. The mixture was then cooled and cut to obtain a HDPE hollow wall plastic-steel wrapped tube.

[0078] Performance Test:

[0079] Ring stiffness: The test was conducted using a universal electronic tensile testing machine in accordance with GB / T9647-2015. The results are shown in Table 1.

[0080] Impact performance: The test was conducted using a drop weight impact tester in accordance with GB / T14152-1993. The results are shown in Table 1.

[0081] Heat aging test: The wound tubes prepared in the examples and comparative examples were aged in a hot water bath at 95°C for 360 h. The ring stiffness after heat aging was tested using a universal electronic tensile testing machine, and the ring stiffness reduction rate was calculated. The results are shown in Table 1.

[0082] Table 1 Performance test results

[0083]

[0084] Data Analysis:

[0085] It can be seen from the data of Examples 1-3 in Table 1 that the HDPE hollow wall plastic-steel wrapped pipe prepared by the present invention has high ring stiffness and impact performance. Most importantly, after aging treatment in a 95°C hot water bath for 360 hours, the ring stiffness decrease rate is only 1.96%, which will greatly improve the durability of the HDPE hollow wall plastic-steel wrapped pipe, making it very suitable for use in application environments that require high stability and durability.

[0086] It can be seen from the data of Example 1 and Comparative Example 1 in Table 1 that the modifier prepared by the present invention effectively improves the ring stiffness and durability of the hollow wall plastic-steel winding pipe, which is mainly due to the reinforcement effect of the glass fiber and the cross-linking effect of sodium polyacrylate on the surface of the glass fiber.

[0087] It can be seen from the data of Example 1 and Comparative Example 2 in Table 1 that the use of phosphoric acid to treat the surface of the steel strip helps to improve the ring stiffness and durability of the hollow wall plastic-steel wrapped pipe. This is mainly because the phosphoric acid treatment can increase the roughness of the steel strip surface and form phosphates on the surface, thereby improving the bonding strength between the steel strip and the inner and outer layer pipes.

[0088] It can be seen from the data of Example 1 and Comparative Examples 1-3 in Table 1 that the sodium polyacrylate on the surface of the modifier and the surface of the steel strip treated with phosphoric acid have the effect of synergistically improving the ring stiffness and durability of the hollow wall plastic-steel wrapped pipe.

[0089] It can be seen from the data of Example 1 and Comparative Example 4 in Table 1 that, compared with the traditional hollow wall wound pipe, the HDPE hollow wall plastic-steel wound pipe provided by the present invention has significantly improved ring stiffness and impact performance, and is particularly suitable for high-load underground pipeline systems.

[0090] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A preparation process for a HDPE hollow wall plastic-steel winding pipe, characterized in that: The following steps are involved: (1) Inner tube extrusion: weigh the inner tube raw material to prepare a mixed material, and then extrude it through an extruder to form a hollow rectangular tube, which is the inner tube; (2) Spiral winding: The extruded inner tube is placed on a winding machine for winding, and hot air is used during the winding process to fuse and connect the wound tubes to obtain a wound inner tube; (3) Steel strip treatment: The steel strip is immersed in a phosphoric acid aqueous solution for phosphating treatment to obtain a surface treated steel strip; (4) Steel strip winding: The surface treated steel strip is wound around the outer wall of the winding inner tube to obtain a steel strip wound tube; (5) Extrusion of outer tube: weigh the outer tube raw materials, prepare a mixed material, extrude it through an extruder, wrap it on the outer surface of the steel belt winding tube, and then cool and cut it to obtain a HDPE hollow wall plastic steel winding tube; The inner tube raw materials include, by weight: 40-60 parts of high-density polyethylene, 4-6 parts of polypropylene, 0.3-0.7 parts of dicumyl peroxide, 1-5 parts of modifier, 1.5-2.5 parts of pentaerythritol stearate and 0.5-2 parts of antioxidant; The outer tube raw materials include, by weight: 40-60 parts of high-density polyethylene, 1.5-2.5 parts of pentaerythritol stearate and 0.5-2 parts of antioxidant; The preparation method of the modifier is as follows: adding glass fiber to deionized water, stirring evenly, adding a sodium acrylate aqueous solution with a concentration of 2 g / L, stirring at 30-40° C. for 25-35 min under a nitrogen atmosphere, then dropping a cerium ammonium nitrate aqueous solution with a concentration of 0.02 g / mL, reacting at 30-40° C. for 2.5-3.5 h, washing and filtering after the reaction is completed, vacuum drying, and finally grinding through a 100-mesh sieve to obtain a modifier; The usage ratio of the glass fiber, deionized water, sodium acrylate aqueous solution and cerium ammonium nitrate aqueous solution is 3g:100mL:20mL:20mL.

2. The preparation process of the HDPE hollow wall plastic-steel wound pipe according to claim 1, characterized in that: In the step (1), the extrusion temperature of the extruder is 220-230° C., the screw speed is 40-60 rpm, and the extrusion pressure is 8-12 MPa.

3. The preparation process of the HDPE hollow wall plastic-steel wound pipe according to claim 1, characterized in that: The dimensions of the inner tube in step (1) are: diameter 200-400 mm, wall thickness 2-4 mm.

4. The preparation process of the HDPE hollow wall plastic-steel wound pipe according to claim 1, characterized in that: In the step (2), the winding angle is 30-45 degrees and the winding speed is 0.5-2 m / min.

5. The preparation process of the HDPE hollow wall plastic-steel wound pipe according to claim 1, characterized in that: The thickness of the steel strip in step (3) is 0.5 mm.

6. The preparation process of the HDPE hollow wall plastic-steel wound pipe according to claim 1, characterized in that: The concentration of the phosphoric acid aqueous solution in step (3) is 8-15wt%, the phosphating time is 8-12min, and the temperature is 70-80°C.

7. The preparation process of the HDPE hollow wall plastic-steel wound pipe according to claim 1, characterized in that: In the step (4), the winding angle is 30-45 degrees and the winding speed is 0.5-2 m / min.

8. The preparation process of the HDPE hollow wall plastic-steel wound pipe according to claim 1, characterized in that: In the step (5), the extrusion temperature of the extruder is 220-230° C., the screw speed is 40-60 rpm, and the extrusion pressure is 8-12 MPa.

9. A HDPE hollow wall plastic steel winding pipe, characterized in that: The hollow wall HDPE plastic-steel wrapped pipe is obtained by the preparation process of any one of claims 1 to 8.

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