A high-strength pipe and a preparation method thereof

Abstract

The present invention discloses a high-strength pipe and a preparation method thereof, belonging to the field of pipeline technology. A high-strength pipe of the present invention is obtained by structurally improving and modifying the composition of traditional pipe materials, and by improving the shape of the pipe and adjusting the material components, so that a pipe that meets the compressive requirements can be formed. When the pipe is buried deep underground, it can withstand the pressure of the backfill soil and will not react with urban sewage, reducing the risk of pipe damage. By increasing the temperature of each part of the extruder, the preparation method can better match the pipe material and produce high-strength pipes that meet the requirements. The pipes prepared by the preparation method of the present invention have excellent anti-stamping performance, load-bearing performance, acid and alkali corrosion resistance, excellent high and low temperature resistance and anti-aging performance. The preparation method is simple to operate, convenient to control, has high production efficiency and low production cost, and can be used for large-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of pipelines, and more specifically, to a high-strength pipe and a preparation method thereof. Background Art

[0002] Due to the development of modern society and the improvement of people's living quality, the requirements for water use have been greatly improved. In order to prevent sewage from overflowing in the city, causing waterlogging and polluting the environment, the municipal government will bury sewage conveyance pipelines underground in the city to convey urban sewage to the sewage treatment plant for sewage treatment, and then discharge it after reaching the standard.

[0003] Bellows are used in many industries, mainly for conveying liquids. For example, stainless steel bellows are flexible and pressure-resistant pipelines, which are widely used in many pipeline extensions or equipment connections, etc. during the conveyance and treatment of municipal sewage. Existing bellows are generally round pipes. Since sewage conveyance pipelines are generally buried underground, the water conveyance bellows need to bear a large pressure. When an ordinary round pipe bears the pressure of backfill soil underground for a long time, the wall support force of the pipe wall will be insufficient after a long time, resulting in the pipe being crushed, thus requiring multiple repairs, which is time-consuming and laborious. In order to increase the compressive performance and load-bearing performance of the pipe and improve the compactness of the lower part of the pipe during construction backfill, many manufacturers will change the corrugation size of the outer wall of the pipe on the outer periphery of the pipe to change the compressive performance of the pipe. However, during use, only changing the corrugation size causes uneven stress on both sides of the pipe, and the compactness of the lower part of the pipe during backfill is insufficient, resulting in pipe deformation and damage, and insufficient pressure resistance and load-bearing capacity of the pipe.

[0004] After retrieval, Chinese patent document CN110649538A discloses a high-impact resistance pillow-shaped composite casing and a casing assembly, including a pipe body and a plurality of impact resistance strengthening ribs arranged on the outer wall of the pipe body. Adjacent two impact resistance strengthening ribs are arranged at intervals. The outer periphery of the impact resistance strengthening rib is square and the four corners of the impact resistance strengthening rib are recessed to form inner rounded corners. Both ends of the pipe body extend outwards with connecting parts. Using its structure, the self-impact resistance ability can be improved. A plurality of impact resistance strengthening ribs are sleeved on the outer wall of the pipe body. By using the structure of the impact resistance strengthening rib and the inner rounded corners formed by the recessed corners, the compressive ability of the impact resistance strengthening rib is improved, and the compressive strength of the high-impact resistance pillow-shaped composite casing in the vertical direction is also improved. At the same time, if the pressures received by a plurality of impact resistance strengthening ribs are different, the force can be transmitted to the pipe body and evenly dispersed and offset, thereby improving the ring stiffness of the high-impact resistance pillow-shaped composite casing and improving its impact resistance strength. However, this application only improves the circumferential strengthening ring outside the bellows, and its improvement is not sufficient to enable the bellows to withstand the pressure of backfill soil for a long time when buried deep underground. Summary of the Invention

[0005] 1. Technical Problems to be Solved by the Invention

[0006] When the existing sewage pipelines are buried underground, the bearing capacity of the backfill soil is insufficient, which easily leads to compression damage. The present invention provides a high-strength pipe and its preparation method to solve the problems mentioned in the background technology.

[0007] 2. Technical solution

[0008] To achieve the above object, the technical solution provided by the present invention is as follows:

[0009] A high-strength pipe of the present invention includes a pipe body. The pipe body includes a pipe wall, and the pipe wall is composed of multiple straight walls and arc walls connected alternately. The straight walls are arranged opposite to each other, and the arc walls are arranged opposite to each other; a plurality of convex rings are sleeved on the outer periphery of the pipe body to form a corrugated structure.

[0010] Furthermore, the convex ring is circumferentially provided with a convex ring groove recessed inward to form a double corrugated structure.

[0011] Furthermore, one end of the pipe body is an insertion section, and the other end is provided with a flared opening, and the inner diameter of the flared opening is larger than the inner diameter of the pipe body.

[0012] Furthermore, the outer periphery of the convex ring is square or has an arc on any one side or has arcs on any two sides or has arcs on any three sides or has arcs on all four sides; the four corners of the convex ring are recessed towards the center to form concave corners.

[0013] A high-strength pipe of the present invention includes the following raw materials in parts by weight:

[0014]

[0015] Among them, polyolefin resin is used as the main material. The polyolefin resin is a mixture of ultra-high molecular weight polyethylene and ordinary polyethylene. The ratio of ultra-high molecular weight polyethylene to ordinary polyethylene is generally 30:70 parts. The molecular weight of ordinary polyethylene is generally between 500,000 and 3 million, and the molecular weight of ultra-high molecular weight polyethylene is above 1.5 million, and some can be as high as 3 million to 4 million. Ultra-high molecular weight polyethylene has higher strength and toughness than ordinary plastics, greatly improving the impact resistance, load-bearing performance and stress cracking resistance of the structural wall pipes. At the same time, it has excellent high-temperature resistance, low-temperature resistance, chemical corrosion resistance, self-lubricating performance and wear resistance, and the surface is smooth and does not scale. Adding ordinary polyethylene resin improves the melt flow performance and molding processing performance. Its molecular weight is lower, and it melts in advance after heating, improving the dispersibility between different components, widening the product molding temperature, and facilitating later cooling and shaping.

[0016] The reinforcing material is a mixture of glass fiber and high-quality silica powder. Adding the reinforcing material can improve the mechanical strength of the structural wall pipe. The glass fiber is alkali-free glass fiber, which can enhance the strength and load-bearing capacity of the pipe. The ratio of glass fiber to silica powder is 1:1.5. The silicon content in the high-quality silica powder is 70-90%, while the silicon content in ordinary silica powder is about 45%. Increasing the silicon content can improve the strength, hardness and durability of the pipe, and at the same time can also improve the appearance quality, processing performance and high chemical stability of the product.

[0017] The compatibilizer is an organosilicon coupling agent. Adding the compatibilizer can improve the compatibility between the reinforcing material and polyolefin, enabling the reinforcing material and polyolefin to link and expand better. The organosilicon coupling agent not only plays a coupling role, improving the compatibility between the reinforcing filler and polyolefin, but also promotes the reinforcing material to play roles such as increasing stiffness, creep resistance, heat distortion temperature and shrinkage rate in polyolefin.

[0018] The anti-aging agent is a mixture of antioxidant and ultraviolet absorber, and the mixing ratio is 2:1. The antioxidant is a mixture of a hindered phenol main antioxidant and a thioether auxiliary antioxidant, which play a coordinating role and are mixed in a weight component ratio of 1:3. Adding the antioxidant can improve the processing stability and weather resistance of the raw material, and at the same time improve the hydrolysis resistance stability of the raw material mixture, thus avoiding its decomposition and aging in a humid and hot environment and reducing its performance. It has good antioxidant effect at high temperature, is not easily hydrolyzed in a high humidity state, and is not easily precipitated, so as to maintain a lasting anti-aging effect. The ultraviolet absorber can prevent the product from decomposing and aging under ultraviolet irradiation in the open state such as storage and transportation, and improve the stability of the pipe. After being buried underground, mainly the antioxidant plays a role, and the role of the ultraviolet absorber is relatively weak.

[0019] The lubricant is kneaded from paraffin oil, paraffin wax and lubricant TAS-2A in a weight fraction ratio of 1:1:2. Adding paraffin wax can improve the melt fluidity of the resin. Paraffin wax can melt at 70-80°C, and as the temperature rises, it continuously penetrates between the ethylene molecular chains, increasing the distance between the macromolecular chains, improving the molecular chain mobility, improving the melt viscosity of the resin, and enhancing its fluidity. The paraffin oil uses light mineral oil, which has a low specific gravity and viscosity, less volatilization, can prevent aging and shrinkage, is beneficial to improving the appearance of the product, improving the surface flatness of the structural wall pipe after molding, and avoiding obvious wrinkles or cracks on the surface of the structural wall pipe. The lubricant TAS-2A can improve the dispersibility of the filled reinforcing material and masterbatch, and also has a certain compatibilizing effect in the silica powder system, appropriately reducing the dosage of the compatibilizer.

[0020] The masterbatch is blue, green, orange, white, black, etc. Adding the masterbatch can make the inner and outer walls of the structural wall pipe have the required colors and bright appearance, and improve the surface brightness of the structural wall pipe.

[0021] A method for preparing a high-strength pipe of the present invention is used to prepare the above-mentioned high-strength pipe, and the steps are as follows:

[0022] Step 1: Weigh the raw materials by weight parts and set aside;

[0023] Step 2: Heat materials such as reinforcing materials, anti-aging agents, lubricants, compatibilizers, and color masterbatches to 70 °C and stir at a rotation speed of 200 - 300 rpm for 15 - 30 min to obtain a premixed mixture;

[0024] Step 3: Add the premixed mixture in Step 2 to the polyolefin mixture containing ultra-high molecular weight polyethylene and mix evenly;

[0025] Step 4: Feed the final mixture obtained in Step 3 into a twin-screw extruder for melt extrusion;

[0026] Step 5: Cool, shape, draw, and cut the extruded molten material through a pipe forming die to obtain a high-strength pipe.

[0027] Furthermore, the temperature of the first zone of the twin-screw extruder is 190 - 200 °C, the temperature of the second zone is 200 - 210 °C, the temperature of the third zone is 200 - 220 °C, the temperature of the fourth zone is 190 - 200 °C, and the temperature of the die head is 185 - 195 °C. The first zone is the heating section, where the material absorbs heat and is conveyed forward under the push of the screw, and a relatively high temperature needs to be set in this zone; the second zone is the melting section, where the material in this zone will absorb a large amount of heat, further heated and melted, and the temperature is slightly higher than that of the first zone; the third zone is the homogenization section, where the temperature is the highest, and the basically melted material is further plasticized and homogenized here to obtain a basically plasticized and uniform molten material; the temperature of the fourth zone is slightly lower than that of the third zone, and the molten material is further plasticized and homogenized in this zone to obtain a completely plasticized and uniform molten material, reducing the temperature to prevent the material temperature from being too high and the viscosity from being too low, which is not conducive to later forming; the temperature of the fifth zone is further reduced to obtain a material with a relatively high viscous flow state. When forming through the die, too high a temperature is not conducive to shaping; too low a temperature, the material has poor ductility, and there are double-wave structures on the outer wall of the structured-wall pipe. When vacuum forming is performed on the outside of the module, the material cannot completely adhere to the inner wall of the module and cannot achieve the ideal structure and appearance, so it affects the forming of the structured-wall pipe, thereby affecting the impact strength, load-bearing capacity, and surface quality of the structured-wall pipe. Therefore, it is necessary to control the die head temperature at 185 - 195 °C.

[0028] 3. Beneficial effects

[0029] Adopting the technical solution provided by the present invention, compared with the existing well-known technologies, it has the following beneficial effects:

[0030] (1) In view of the situation that when the existing sewage pipelines are buried underground, the bearing capacity of the backfill soil is insufficient, which easily leads to compression damage, a high-strength pipe of the present invention is provided. A plurality of spaced convex rings are arranged circumferentially on the ordinary circular pipe, transforming the ordinary circular pipe into a corrugated pipe, increasing the strength of the circular pipe. At the same time, on the basis of the corrugated pipe, a convex ring groove that is recessed inward is further arranged on the convex ring, so that the convex ring that can originally improve the strength further enhances its strengthening effect, enabling the circular pipe to withstand greater backfill soil pressure when underground.

[0031] (2) The cross-section of a high-strength pipe of the present invention is not a traditional circle, but arc-shaped walls and straight walls are alternately arranged. Among them, the two arc-shaped walls at both ends are arranged opposite to each other, located at the upper and lower parts of the pipe body, and the two straight walls are arranged opposite to each other, located at the left and right parts of the pipe body. Since the side walls of the corrugated pipe are hardly subjected to the pressure of the backfill soil when it is buried underground, the main pressure comes from the upper and lower directions. Setting the side walls as straight walls can provide more support for the upper and lower arc-shaped walls, thereby preventing deformation due to upper and lower forces. At the same time, the upper and lower arc-shaped walls form an arch structure, which can withstand greater forces. In addition, for sewage pipelines, the arc-shaped bottom surface can prevent the accumulation of dirt.

[0032] (3) A high-strength pipe of the present invention modifies the traditional pipe material. By adjusting the material components, it can form a pipe that meets the compressive requirements, enabling the pipe to withstand the pressure of the backfill soil when buried deep underground and not react with urban sewage at the same time, reducing the risk of pipe damage.

[0033] (4) A preparation method of a high-strength pipe of the present invention adjusts the temperature of each part of the extruder, so that the preparation method can better match the pipe material and produce a high-strength pipe that meets the requirements. The pipe prepared by the preparation method of the present invention has excellent anti-stamping performance, bearing performance, acid and alkali corrosion resistance, excellent high and low temperature resistance and anti-aging performance. This preparation method is simple to operate, convenient to control, has high production efficiency and low production cost, and can be used for large-scale production. Description of the Drawings

[0034] Figure 1 Schematic diagram of the connection of two corrugated pipes of the present invention;

[0035] Figure 2 Schematic diagram of the structure of the corrugated pipe of the present invention when it is sleeved with a sealing member and an anti-retreat member;

[0036] Figure 3 Schematic diagram of the corrugated pipe structure of the present invention;

[0037] Figure 4 Schematic diagram of the structure of the corrugated pipe of the present invention from another perspective;

[0038] Figure 5 Front view of the corrugated pipe of the present invention;

[0039] Figure 6 is Figure 5 Cross-sectional view taken along line A-A in

[0040] Figure 7 Schematic structural diagram of the seal of the present invention;

[0041] Figure 8 Schematic structural diagram of the anti-retreat member of the present invention;

[0042] Figure 9 Side view of the anti-retreat member of the present invention;

[0043] Figure 10 Load stress simulation of the pipe material of the present invention Figure 1 ;

[0044] Figure 11 Load stress simulation of the pipe material of the present invention Figure 2 ;

[0045] Figure 12 Side view of another form of corrugated pipe of the present invention.

[0046] Explanation of the reference numerals in the schematic diagram:

[0047] 1. Pipe body; 11. Pipe wall; 111. Straight wall; 112. Arc wall; 113. Vent hole; 12. Convex ring; 121. Concave angle; 13. Convex ring groove; 14. Corrugation groove; 15. Flared opening; 16. Outer protrusion; 17. Anti-retreat groove; 18. Sealing clip; 2. Anti-retreat member; 21. Clamping ring; 22. Inclined platform; 3. Seal; 31. Sealing ring; 32. Sealing groove. Detailed implementation manners

[0048] To further understand the content of the present invention, the present invention will be described in detail in combination with the accompanying drawings and embodiments.

[0049] Embodiment 1

[0050] Combined with Figures 1 - 9 , a high-strength pipe of this embodiment improves the structural strength of the pipe body 1 by improving the shape of the ordinary round pipe, enabling it to bear more of the pressure of the backfill soil when buried underground, increasing its service life, and reducing the number of maintenance times.

[0051] Specifically, referring to Figures 1 - 3, A high-strength pipe of this embodiment includes a pipe body 1. The pipe body 1 includes a pipe wall 11, and the pipe wall 11 encloses a channel along the length direction of the pipe body 1; a plurality of spaced convex rings 12 are arranged circumferentially on the outer side of the pipe wall 11, with corrugated grooves 14 formed at intervals; an inwardly recessed convex ring groove 13 is arranged circumferentially on the convex ring 12. In this embodiment, a plurality of spaced convex rings 12 are arranged circumferentially on the ordinary circular pipe, transforming the ordinary circular pipe into a corrugated pipe, increasing the strength of the circular pipe; at the same time, on the basis of the corrugated pipe, an inwardly recessed convex ring groove 13 is further arranged on the convex ring 12, so that the convex ring 12 that can originally improve the strength further improves its strengthening effect, enabling the circular pipe to withstand greater backfill soil pressure when underground. In this embodiment, the outer periphery of the convex ring 12 is square; the four corners of the convex ring 12 are recessed towards the center to form concave corners 121. Since the four corners of the convex ring 12 are recessed towards the center to form concave corners 121, the compressive capacity of the convex ring 12 can be improved, and at the same time, the collision of the four protruding corners during installation is avoided, facilitating the installation of the corrugated pipe assembly.

[0052] Combined with Figures 7 - 9 , In this embodiment, an anti-retreat member 2 and a sealing member 3 are arranged at one end of the pipe body 1. Both are sleeved in the corrugated groove 14 and are located in different corrugated grooves 14 from the sealing member 3. Among them, the sealing member 3 is closer to the end of the pipe body 1. In this embodiment, the sealing member 3 includes a sealing ring 31, and a sealing groove 32 is formed circumferentially along the sealing ring 31. The anti-retreat member 2 includes a clamping ring 21, and a bevel 22 is arranged circumferentially on the clamping ring 21, so that the clamping ring 21 forms a structure with one end large and one end small. In this embodiment, the anti-retreat member 2 and the sealing member 3 are arranged at one end of the pipe body 1, and a flared opening 15 is arranged at the other end of the pipe body 1. The inner diameter of the flared opening 15 is larger than the inner diameter of the pipe body 1. The flared opening 15 is communicated with the pipe body 1, and the connection between the two is in arc transition.

[0053] Combined with Figure 4 , In this embodiment, an anti-retreat groove 17 is formed on the inner wall of the flared opening 15, and the opening of the anti-retreat groove 17 faces the pipe body 1. At the same time, a sealing clamp 18 is arranged on the inner wall of the flared opening 15; during installation, first sleeve the anti-retreat member 2 and the sealing member 3 on one end of a pipe body 1, and then insert this end into the flared opening 15 of another pipe body 1. At this time, the anti-retreat member 2 is clamped into the anti-retreat groove 17, and the sealing clamp 18 is clamped into the sealing groove 32 on the sealing member 3. The two fix the two pipe bodies 1 at the same time to prevent them from shifting. At the same time, the sealing member 3 also plays a sealing role. In this embodiment, since the bevel 22 is arranged circumferentially on the anti-retreat member 2 to form a shape with one end large and one end small, it can be easily inserted when the two pipe bodies 1 are connected. After the bevel 22 is clamped into the anti-retreat groove 17, it is not easy to fall off. In this embodiment, due to the formation of the anti-retreat groove 17, an outwardly protruding outer convex 16 is formed on the outer wall, and the outer convex 16 functions as a reinforcing rib and can improve the strength of the flared opening 15.

[0054] Combined with Figure 6, in this embodiment, the pipe wall 11 includes a straight wall 111 and an arc wall 112. The straight walls 111 and the arc walls 112 are alternately connected to form the pipe wall 11. The straight walls 111 are arranged opposite to each other, and the arc walls 112 are arranged opposite to each other. It should be noted that the cross-section of the corrugated pipe in this embodiment is not the traditional circular shape, but the arc walls 112 and the straight walls 111 are alternately arranged. The two arc walls 112 at both ends are arranged opposite to each other and are located at the upper and lower parts of the pipe body 1. The two straight walls 111 are arranged opposite to each other and are located at the left and right parts of the pipe body 1. Since the side walls of the corrugated pipe are hardly affected by the backfill soil pressure when it is installed underground, the main pressure comes from the upper and lower directions. The side walls are arranged as straight walls 111, which can provide more supporting force for the upper and lower arc walls 112, thus preventing deformation under the upper and lower forces. At the same time, the upper and lower arc walls 112 form an arch structure, which can bear greater forces. In addition, for the sewage delivery pipe, the arc-shaped bottom surface can prevent the accumulation of dirt. When a load acts on the pipe body 1, it first acts on the convex ring 12 that forms the double corrugation. Through the force decomposition of the double corrugation, a part of the force is absorbed by the double corrugation support force and deformation, a part is supported and decomposed by the reinforcing ribs, and the other part is transmitted to the pipe body 1. The force received by the pipe body 1 is decomposed into vertical and horizontal directions. The vertical force is loaded on the pipe body 1 and transmitted to the vertical straight walls 111 on both sides of the pipe body 1, and then transmitted to the bottom base layer under the pipe body 1. A part of the horizontal force decomposed on the upper part of the pipe body 1 is transmitted to the bottom base layer through the vertical edge of the pipe body 1, and a part is offset by the external soil pressure when the pipe body 1 is backfilled. This high-strength and high-toughness structural wall pipe body 1 greatly improves the impact resistance and bearing capacity of the pipe body 1. From Figures 10 - 11 it can be seen that when a load is applied in the vertical direction, the stress distributed on the side walls is small. Through the finite element analysis of the product in this embodiment, Tables 1 and 2 are obtained. The test standard for the ring stiffness is tested according to the standards specified in "GBT 9647-201 Thermoplastic Pipe Ring Stiffness Determination" and "ISO9969:2007". The material properties are as follows:

[0055] Table 1 Main Performance Parameters of Materials

[0056]

[0057] Table 2 Ring Stiffness Values (Loads on the Upper and Lower Surfaces)

[0058]

[0059] Table 3 Ring Stiffness Values (Loads on the Left and Right Horizontal Planes)

[0060]

[0061] It can be seen from the content in the table that the ring stiffness of the product obtained in this embodiment reaches 26.98 KN / m2, and its load level is high.

[0062] In this embodiment, a plurality of ventilation holes 113 are provided between the convex ring 12 and the pipe wall 11, and the ventilation holes 113 are arranged along the length direction of the pipe wall 11. The ventilation holes 113 provided in this embodiment facilitate blowing air between the convex ring 12 and the pipe wall 11. During manufacturing, the blown gas can separate the two layers of materials, facilitating the shaping device to perform shaping processing on the convex ring 12. Combining Figure 12 , the outer shape of the convex ring 12 in this embodiment can be square or a shape with any one side being arc-shaped or any two sides being arc-shaped or any three sides being arc-shaped or all four sides being arc-shaped.

[0063] Embodiment 2

[0064] The high-strength pipe material comprises the following raw materials in parts by weight

[0065]

[0066] The raw materials are a mixture of ultra-high molecular weight polyethylene and polyethylene in a weight ratio of 3.5:6.5; the ultra-high molecular weight polyethylene is a linear polyethylene with a molecular weight of more than 1.5 million and no branches, a density of 0.93 - 0.95 g / cm3, and a melt index of less than 0.5 g / 10 min under the test conditions of 230 °C / 2.16 kg, with poor flow performance. The polyethylene is a high-density polyethylene with a density of 0.95 g / cm3 and a melt index of less than 2.0 g / 10 min under the test conditions of 230 °C / 2.16 kg, and the model of the high-density polyethylene is PE100 grade.

[0067] The reinforcing material is a mixture of glass fiber and silica fume, and the two are used in a ratio of 1:2. The glass fiber is an alkali-free glass fiber, which has good toughness and is easy to mix and disperse with the resin; the silica fume has a silicon content of 70 - 90%, and the high silicon content enhances the strength of the mixed material. The silicon content of ordinary silica fume is 40 - 50%.

[0068] The anti-aging agent is mainly a combination of an antioxidant and a light stabilizer, and the mixing ratio is 2:1. The antioxidant is a combination of a hindered phenol main antioxidant (antioxidant 1010 or 168) and a thioether auxiliary antioxidant (MIANOX1035) that play a coordinating role and are mixed in a weight component ratio of 1:3. The light stabilizer is light stabilizer 944, which has an absorption effect on most wavelengths of light, keeps the internal molecules of the material stable, extends the service life, and reduces the reduction of the use performance due to the action of light.

[0069] The lubricant is composed of paraffin oil, paraffin wax and lubricant TAS-2A mixed in a weight ratio of 1:1:3.

[0070] The compatibilizer is composed of methyl silicone and silicone in a weight ratio of 1:1. It links the inorganic reinforcing material and the organic resin material, improves the compatibility, and improves the processing performance and mechanical properties of the raw materials.

[0071] The color masterbatch is obtained by granulating a mixture of pigments such as blue, green, orange, white, and black and a polyolefin substrate.

[0072] The preparation method of the pipe comprises the following steps:

[0073] Step 1: Weigh the raw materials by weight parts and set aside;

[0074] Step 2: Take ultra-high molecular weight polyethylene and polyolefin, mix and dry them at a temperature of 70 °C, and set aside;

[0075] Step 3: Take antioxidants, compatibilizers, reinforcing fillers, lubricants, color masterbatch, etc., mix them, and stir at a speed of 400 rpm for 15 min to obtain a mixed material;

[0076] Step 4: Add the material treated in Step 2 to the mixed material obtained in Step 3, mix evenly, and then send it into a twin-screw extruder for melt extrusion;

[0077] Step 5: Cool, shape, draw, and cut the extruded molten material through a pipe forming die to obtain a high-strength pipe.

[0078] In the said Step 4, the screw speed of the twin-screw extruder is 110 r / min, the temperature of the first zone of the twin-screw extruder is 195 °C, the temperature of the second zone is 210 °C, the temperature of the third zone is 195 °C, the temperature of the fourth zone is 185 °C, the temperature of the fifth zone is 185 °C, and the die head temperature is 190 °C.

[0079] Example 3

[0080] The said high-strength pipe comprises the following raw materials by weight parts

[0081]

[0082]

[0083] The specific raw material ratios and preparation methods of each component are the same as those in Example 2.

[0084] Example 4

[0085] The said high-strength pipe comprises the following raw materials by weight parts

[0086] The specific raw material ratios and preparation methods of each component are the same as those in Example 2.

[0087] Example 5

[0088] The said high-strength pipe comprises the following raw materials by weight parts

[0089] The specific raw material ratios and preparation methods of the respective components are the same as those in Example 2.

[0090] Example 6

[0091] The high-strength pipe comprises the following raw materials in parts by weight

[0092] The specific raw material ratios and preparation methods of the respective components are the same as those in Example 2.

[0093] Performance tests were carried out on Examples 2 - 6, and the test results are shown in Table 4.

[0094] Table 4 Test Results

[0095] Test Items Example 2 Example 3 Example 4 Example 5 Comparative Example 6 Ring Stiffness (kN / m2) 33 41 30 37 45 Ring Flexibility No Breakage and No Disconnection No Breakage and No Disconnection No Breakage and No Disconnection No Breakage and No Disconnection No Breakage and No Disconnection Vicat Softening Temperature (°C) 129 152 120 143 160 Falling Dart Impact (%) No Failure No Failure No Failure No Failure No Failure Oven Test No Delamination, Cracking or Blistering No Delamination, Cracking or Blistering No Delamination, Cracking or Blistering No Delamination, Cracking or Blistering No Delamination, Cracking or Blistering Oxidation Induction (min) 45 55 42 49 60

[0096] The selected high-strength pipes are all: the nominal inner diameter is 297 mm, the minimum inner layer flat wall thickness is 1.5 mm, the minimum outer wall thickness is 2.5 mm, the length is based on the detection standard, the cutting position is at the wave trough, and the corrugated structure cannot be damaged. Ring stiffness test, ring flexibility test, Vicat softening temperature test, falling weight impact test, oven test, oxidation induction test, etc. were carried out on it.

[0097] The test methods are as follows:

[0098] 1. Ring stiffness test: The test is carried out at 23 ± 2 °C in accordance with the provisions of GB / T9647 - 2015, and the unit is kN / m2.

[0099] 2. Ring flexibility test: The test is carried out according to ISO13968 - 2008. The length of the specimen is 300 mm, the cutting position is at the wave trough, and the test force should be continuously doubled. When the outer diameter deformation of the specimen in the vertical direction is 30% of the original outer diameter, immediately unload, and observe whether the pipe specimen is broken, whether the inner and outer walls are separated, and whether the inner wall has reverse bending.

[0100] 3. Vicat softening temperature test: The test is carried out in accordance with the provisions of GB / T1633 - 2000, and the A50 method is used for determination. The applied load is 1 kg, and the unit is °C.

[0101] 4. Falling weight impact test: Sampling and testing are carried out in accordance with the provisions of GB / T14152 - 2001. The hammer head of the falling weight is of D90 type. The specimen should be pre-treated at -5 ± 1 °C for 2 h. The length of the specimen is 200 ± 10 mm, the mass of the falling weight is 3.2 kg, and the impact height is 2000 mm. The falling weight impacts the outer wall of the specimen from the top once, and observe the specimen after impact. If there is no breakage, it is qualified. The number of specimens is 10.

[0102] 5. Oven test: Conduct according to the provisions of 8.7 in GB / T 19472.1-2019. The sample is qualified if there is no delamination, cracking or blistering.

[0103] 6. Oxidation induction test: Conduct according to the provisions of GB / T 19466.6. The test temperature is 200 °C, and the inner and outer walls are measured separately. The original surface is facing up for the test. The number of test samples is 3 for each, and the minimum value is taken.

[0104] As can be seen from Table 4, the ring stiffness of the high-strength pipe of the present invention tested by the above method can all reach more than 30 kN / m2, the Vicat softening temperature reaches more than 120 °C, the passing rate of the falling weight impact test samples reaches 100%, the passing rate of the ring flexibility reaches 100%, and the oxidation induction reaches more than 42 minutes. The high-strength pipe of the present invention has the advantages of high strength, high toughness, high impact resistance, high load, high heat resistance, high anti-aging property, environmental protection, etc.

[0105] The above schematically describes the present invention and its implementation manners. This description is not restrictive. What is shown in the drawings is only one of the implementation manners of the present invention, and the actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design similar structural manners and embodiments without creative efforts without departing from the gist of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A high-strength pipe, characterized in that, it includes a pipe body (1), the pipe body (1) includes a pipe wall (11), the pipe wall (11) is composed of a plurality of straight walls (111) and arc walls (112) connected alternately, the straight walls (111) are arranged opposite to each other, and the arc walls (112) are arranged opposite to each other; a plurality of convex rings (12) are arranged at intervals on the outer periphery of the pipe body (1), and corrugated grooves (14) are formed at intervals; one end of the pipe body (1) is an insertion section, and the other end is provided with a flared opening (15), the inner diameter of the flared opening (15) is larger than the inner diameter of the pipe body (1), an anti-retreat groove (17) is opened on the inner wall of the flared opening (15), and a sealing clip (18) is provided; an anti-retreat member (2) and a sealing member (3) are arranged on the insertion section, the anti-retreat member (2) and the sealing member (3) are respectively sleeved in different corrugated grooves (14), and the sealing member (3) is closer to the end of the pipe body (1); the sealing member (3) includes a sealing ring (31), and a sealing groove (32) is opened along the circumference of the sealing ring (31); the anti-retreat member (2) includes a clamping ring (21), and a bevel (22) is arranged circumferentially on the clamping ring (21); the anti-retreat member (2) is used for being clamped into the anti-retreat groove (17), and the sealing groove (32) is used for being clamped into the sealing clip (18); The pipe comprises the following raw materials in parts by weight: 35 parts of ultra-high molecular weight polyethylene 65 parts of polyolefin 20 parts of reinforcing material 2 parts of anti-aging agent 2 parts of lubricant 1 part of compatibilizer 4 parts of masterbatch; The polyolefin is polyethylene, the ultra-high molecular weight polyethylene is linear polyethylene without branches with a molecular weight of more than 1.5 million, the density is 0.93 - 0.95 g / cm3, and the melt index under the test conditions of 230 °C / 2.16 kg is below 0.5 g / 10 min; the polyethylene is high-density polyethylene with a density of 0.95 g / cm3 and a melt index under the test conditions of 230 °C / 2.16 kg below 2.0 g / 10 min, and the model of the high-density polyethylene is PE100 grade; the reinforcing material is a mixture of glass fiber and high-quality silica powder with a silicon content of 70 - 90%, and the ratio of glass fiber to silica powder is 1:1.5; The anti-aging agent is a mixture of antioxidant and ultraviolet absorber, and the mixing ratio is 2:1; among them, the antioxidant is a mixture of a hindered phenol main antioxidant and a thioether auxiliary antioxidant according to the weight component ratio of 1:3; The lubricant is composed of paraffin oil, paraffin and lubricant TAS-2A mixed according to the weight fraction ratio of 1:1:2; The compatibilizer is a mixture of siloxane and silicone in a weight ratio of 1:

1.

2. A high-strength pipe according to claim 1, characterized in that, a convex ring groove (13) recessed inward is opened circumferentially on the convex ring (12) to form a double corrugated structure.

3. A high-strength pipe according to claim 1, characterized in that, The outer periphery of the convex ring (12) is square or has an arc on any one side or arcs on any two sides or arcs on any three sides or arcs on all four sides; the four corners of the convex ring (12) are recessed towards the center to form concave corners (121).

4. A method for preparing a high-strength pipe, used for preparing the high-strength pipe according to any one of claims 1-3, characterized in that, its steps are as follows: Step 1: Weigh the raw materials by weight parts and set aside; Step 2: Heat the reinforcing material, anti-aging agent, lubricant, compatibilizer, and color masterbatch material to 70°C and stir at a rotation speed of 200-300 rpm for 15-30 minutes to obtain a premixed mixture; Step 3: Add the premixed mixture in Step 2 to the polyolefin mixture containing ultra-high molecular weight polyethylene and mix evenly again; Step 4: Feed the final mixture obtained in Step 3 into a twin-screw extruder for melt extrusion; Step 5: Cool, shape, draw, and cut the extruded molten material through a pipe forming die to obtain a high-strength pipe.

5. According to the method for preparing a high-strength pipe described in claim 4, characterized in that, the temperature of the first zone of the twin-screw extruder is 190-200°C, the temperature of the second zone is 200-210°C, the temperature of the third zone is 200-220°C, the temperature of the fourth zone is 190-200°C, and the die head temperature is 185-195°C.

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