High-strength cable protection pipe for communication and preparation process thereof

Abstract

This invention relates to the field of pipe processing technology, and discloses a high-strength cable protection pipe for communication and its preparation process. The pipe is made from the following raw materials in parts by weight: 100 parts high-density polyethylene, 15-20 parts needle-like wollastonite powder, 5-8 parts maleic anhydride-grafted polyethylene, 0.2-0.3 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.2-0.3 parts tris(2,4-di-tert-butylphenyl) phosphite, and 2.25-3.55 parts side-feed liquid suspension slurry. The slurry contains epoxidized soybean oil, pentaerythritol, and zinc stearate. The solid raw materials are dry-mixed and fed into a co-rotating twin-screw extruder. The slurry is continuously injected during the polymer melt extrusion process, and after degassing and pelletizing, a modified masterbatch is obtained. The modified masterbatch is then fed into a single-screw pipe extruder for secondary melting and molding, followed by cooling and sizing to obtain the pipe. This invention improves the dispersibility of inorganic fillers, enhances processing stability, and increases pipe strength.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipe processing, in particular to a high-strength cable protection pipe for communication and a preparation process thereof. BACKGROUND

[0002] The high-density polyethylene cable protection pipe needs to have high mechanical bearing capacity in practical application, and the pipe strength is usually improved by adding inorganic rigid fillers. Since the polyethylene matrix is non-polar, the interface compatibility with the inorganic fillers is poor, and micro interface defects are easily generated between the two phases. Under the stress state, the matrix cannot effectively transmit the stress to the rigid filler, so that the tensile strength and rigidity of the pipe are difficult to reach the expected standard.

[0003] To solve the processing fluidity problem of high filler material, the prior art directly mixes in solid lubricant in the main feeding stage. This feeding mode easily causes the screw of the extruder to slip and the feeding amount to fluctuate. At the same time, the solid particles are difficult to uniformly disperse in the melt with high temperature and high viscosity, and cannot effectively absorb the heat generated by mechanical shearing, so that the apparent viscosity of the melt is unstable, and it is difficult to maintain the continuity of the pipe extrusion processing process.

[0004] In the pipe extrusion molding process, the existing processing process is often difficult to balance mixing and degassing and molding control. In conventional processing, if the small molecular water and volatile matter generated by mixing reaction are not extracted in time, micro-pore defects will be formed on the pipe wall. At the same time, improper heating mode control easily causes the material to melt too early and causes uneven plasticization, and if the pipe surface is not quickly crystallized and solidified in the molding sizing stage, the structural density and outer diameter size accuracy of the finished product will be directly affected. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a high-strength cable protection pipe for communication and a preparation process thereof, which solves the problems that in the process of adding a high proportion of inorganic rigid fillers to improve the mechanical strength of the existing high-density polyethylene cable protection pipe, the fillers are easy to agglomerate, the interface compatibility between the polymer matrix and the fillers is poor, the melt fluidity is reduced, the pipe extrusion processing is difficult, and the mechanical properties of the finished product fluctuate.

[0006] To achieve the above purpose, the present application is realized by the following technical scheme:

[0007] In a first aspect, the present application provides a high-strength cable protection pipe for communication, which is made of raw materials containing the following weight parts:

[0008] High density polyethylene 100 parts; acicular wollastonite powder 15-20 parts; maleic anhydride grafted polyethylene 5-8 parts; tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester 0.2-0.3 parts; tris(2,4-di-tert-butylphenyl) phosphite 0.2-0.3 parts; side-feeding liquid suspension slurry 2.25-3.55 parts;

[0009] The side-feeding liquid suspension slurry comprises raw materials of epoxy soybean oil, pentaerythritol and zinc stearate.

[0010] By adopting the technical scheme, the processing performance and mechanical properties of the high filling system are improved through the interaction of the components, and the specific reaction process and action mechanism are as follows:

[0011] In the first step, an interface chemical reaction occurs. In the molten state, the anhydride groups on the molecular chain of the maleic anhydride grafted polyethylene react with the silicon hydroxyl groups on the surface of the acicular wollastonite powder to generate a single ester bond and a carboxyl group. This reaction introduces a non-polar polyethylene long molecular chain onto the surface of the wollastonite powder, increases the interfacial compatibility of the wollastonite and the high density polyethylene matrix, reduces the micro defects on the surface of the filler, and enables the stress to be transmitted to the rigid filler when the matrix is stressed, thereby increasing the tensile strength of the pipe.

[0012] In the second step, a liquid lubricating dispersion system is formed. The epoxy soybean oil acts as a liquid carrier and an internal lubricant, enters the polymer molecular chain to increase the free volume and reduce the melt viscosity; the zinc stearate acts as an external lubricant to form a lubricating layer on the inner wall of the metal cylinder; the pentaerythritol utilizes its hydroxyl groups to form intermolecular forces with the epoxy soybean oil, so that the solid powder remains suspended in the oil phase without settling. The three are compounded and injected in a liquid state through a side-feeding form, which improves the problem of screw feed quantity fluctuation caused by the addition of the solid powder lubricant at the main feeding port.

[0013] In the third step, the antioxidants play a synergistic role. Tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester acts as a primary antioxidant to capture free radicals, and tris(2,4-di-tert-butylphenyl) phosphite acts as a secondary antioxidant to decompose peroxides. When the polymer melt and the side-feeding liquid suspension slurry are mixed under the shearing of the twin screw, the epoxy soybean oil coats the wollastonite powder and blocks the electrostatic adsorption between the fillers, in combination with the above antioxidant combination, the thermal oxidative degradation in the processing process is slowed down. Therefore, a mechanically stable and continuously extruded communication high-strength cable protection pipe is obtained.

[0014] Preferably, the particle size D50 of the pentaerythritol is 10-15 μm, and the water content is less than or equal to 0.05%; the epoxy value of the epoxy soybean oil is 6.0%-6.5%.

[0015] By adopting the above technical solution, pentaerythritol powder with a particle size D50 limited to 10-15μm can form a space-filling structure with zinc stearate particles, creating a suspended network in epoxidized soybean oil and preventing the solid phase from settling and precipitating during pipeline transportation. A moisture content of less than or equal to 0.05% limits the introduction of moisture into the melt, preventing melt foaming and the formation of pores on the pipe wall. Epoxidized soybean oil with an epoxy value of 6.0%-6.5% possesses moderate polarity, ensuring both the wettability of the liquid phase to solid particles and preventing abnormal increases in localized melt viscosity due to excessive cross-linking.

[0016] Preferably, the preparation process of the side-feed liquid suspension slurry includes: adding 2.0-3.0 parts by weight of the epoxidized soybean oil to a mixing tank equipped with a circulation loop and a high-shear homogenizer; adding 0.05-0.15 parts by weight of the pentaerythritol and 0.2-0.4 parts by weight of the zinc stearate while stirring; turning on the high-shear homogenizer; setting the rotation speed to 1000-1500 rpm; and continuing the process for 20-30 minutes.

[0017] By employing the above technical solution, the high-shear homogenizer generates fluid shearing action, dispersing solid pentaerythritol and zinc stearate in epoxidized soybean oil. The batching tank with a circulation loop ensures the material repeatedly passes through the shearing zone, causing the surface of solid particles to be coated with the liquid phase, forming a liquid suspension. This state of the slurry meets the fluid requirements for continuous metering by the liquid injection pump, maintaining a continuous supply of lubricant within the extruder.

[0018] Secondly, the present invention provides a manufacturing process for a high-strength cable protection pipe for communication, which is applied to the high-strength cable protection pipe for communication, and includes the following steps:

[0019] The needle-shaped wollastonite powder was placed in an oven and dried with hot air.

[0020] High-density polyethylene, pre-dried needle-shaped wollastonite powder, maleic anhydride-grafted polyethylene, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite are put into a high-speed mixer, the stirring is turned on and the mixture is stirred and mixed, and the mixed material is fed into the main feed port of a co-rotating twin-screw extruder.

[0021] The fed material is heated and melted in the co-rotating twin-screw extruder to form a polymer melt, which is then extruded forward. During the forward extrusion of the polymer melt, a liquid injection pump is started to continuously inject the side-feed liquid suspension slurry into the polymer melt in the co-rotating twin-screw extruder for mixing.

[0022] Open the vacuum exhaust port to exhaust the mixed polymer melt;

[0023] After the venting is completed, the polymer melt is extruded through the die of the co-rotating twin-screw extruder to form a strip. The strip is then cooled, and the cooled strip is pelletized to obtain modified masterbatch. The modified masterbatch is then dried with hot air.

[0024] The dried modified masterbatch is fed into a single-screw pipe extruder and heated to melt, forming a pipe polymer melt. The pipe polymer melt is extruded through the forming die of the single-screw pipe extruder to form a pipe. The pipe is then introduced into a vacuum sizing tank for cooling and shaping. The cooled and shaped pipe is then pulled and cut to obtain a high-strength cable protection pipe for communication.

[0025] By adopting the above technical solution, the preparation process mechanism steps of the present invention are as follows:

[0026] The first step is solid-phase pre-drying and dry-phase mixing. The inorganic filler is dried with hot air to remove surface-adsorbed moisture, preventing hydrolysis and breakage of the polymer chains during subsequent high-temperature processing. The solid raw materials, excluding the side-feed liquid suspension slurry, are then stirred and dry-mixed in a high-speed mixer. No lubricating components are introduced at this stage to maintain the friction coefficient of the material system, achieving initial mixing of the solid powders through mechanical action.

[0027] The second step involves reactive extrusion and interfacial chemical bonding. The dry-mixed material enters a co-rotating twin-screw extruder and is heated and melted. Since there is no lubricant in the system, the screw applies mechanical shear to the polymer melt and needle-like wollastonite powder. The shear stress generates frictional heat, which promotes the ring-opening of the anhydride groups of maleic anhydride-grafted polyethylene and esterification with the hydroxyl groups on the surface of the needle-like wollastonite powder. At the same time, the mechanical shear force breaks down the filler aggregates and increases the interfacial contact area.

[0028] The third step is liquid-phase side-feeding injection and dispersion. After the polymer melt is extruded forward and the esterification reaction has progressed to a certain extent, a side-feed liquid suspension slurry is injected into the melt through the side feed port. The liquid slurry directly enters the melt, reducing the apparent viscosity of the melt, absorbing the heat generated by shearing, and preventing localized thermal degradation of the polymer. The zinc stearate and pentaerythritol particles suspended in the slurry are dispersed with the melt flow.

[0029] The fourth step is devolatilization and secondary molding and curing. The vacuum exhaust port is opened to extract the small-molecule water and low-molecular-weight volatiles generated during the esterification reaction, preventing micropores from forming in the product. Primary plasticization is achieved by preparing modified masterbatch, followed by secondary melt extrusion molding in a single-screw pipe extruder. After the polymer melt is extruded in the molding die, it undergoes sizing in a vacuum sizing tank and heat exchange with cooling water. The polymer chains crystallize under rapid cooling conditions, fixing the needle-like wollastonite powder within the resin matrix, thus completing the preparation of the high-strength cable protection pipe for communication applications.

[0030] Preferably, the hot air drying temperature is 105-120℃ and the time is 2-4h; the speed in the high-speed mixer is set to 300-500rpm, and the mixing is carried out at room temperature for 3-5min; the mixed material is then transferred to a loss-in-weight feeder and fed into the main feed port of the co-rotating twin-screw extruder.

[0031] By employing the above technical solution and treating the material at 105-120℃ for 2-4 hours, the physically adsorbed water on the surface of the needle-shaped wollastonite powder can be removed, while retaining the internal crystal water to maintain the rigid structure of the filler. The centrifugal force of the high-speed mixer disperses the powder and granular materials. Using a loss-in-weight feeder allows for real-time monitoring and adjustment of the mass flow rate of the falling solid material, maintaining a constant pressure within the twin-screw extruder.

[0032] Preferably, the co-rotating twin-screw extruder has a length-to-diameter ratio of 40 and a screw speed of 300-400 rpm; the barrel of the co-rotating twin-screw extruder is divided into 10 temperature control zones along the forward extrusion direction of the polymer melt, wherein the barrel temperature of zones 1-4 is 200-210℃, the barrel temperature of zones 5-8 is 185-190℃, and the barrel temperature of zones 9-10 is 190-195℃; the side-feed liquid suspension slurry is injected when the polymer melt reaches zone 5; before the side-feed liquid suspension slurry is injected into the co-rotating twin-screw extruder, it is stirred at a speed of 60-100 rpm in the mixing tank and refluxed online.

[0033] By employing the above technical solution, a length-to-diameter ratio of 40 provides sufficient material residence time. Zones 1-4 have higher temperatures to promote the melting of high-density polyethylene; zones 5-8 lower the temperature to 185-190℃, increasing melt viscosity. In zone 5, a liquid suspension slurry is fed to the injection side; the high-viscosity melt exerts a shearing and stretching effect on the injected liquid slurry, dispersing the liquid phase into the matrix. Zones 9-10 raise the temperature to increase melt fluidity. Before injection, stirring and online reflux are maintained in the mixing tank to keep the slurry flowing and prevent the settling of pentaerythritol and zinc stearate solid particles in the pipeline and pump body.

[0034] Preferably, the exhaust vacuum degree of the vacuum exhaust port is controlled between -0.08 and -0.09 MPa; the cooling of the strip is to introduce the strip into a room temperature water bath at 20-30℃ for cooling; and the modified masterbatch is dried at 80-85℃ for 2-4 hours.

[0035] By employing the above technical solution, a pressure gradient is generated under a negative pressure state of -0.08 to -0.09 MPa, driving volatile gases to diffuse towards the melt surface and be discharged. A water bath temperature of 20-30℃ cools the extruded strips, preventing internal stress from forming on the masterbatch surface due to excessive temperature differences. The modified masterbatch is dried at 80-85℃, and hot air removes free water adhering to the masterbatch surface during pelletizing, preventing moisture from entering the single-screw pipe extruder along with the masterbatch.

[0036] Preferably, the length-to-diameter ratio of the single-screw pipe extruder is 30-33; the barrel heating zone of the single-screw pipe extruder includes four zones, with the temperatures set sequentially as follows: Zone 1 180-185℃, Zone 2 190-195℃, Zone 3 200-205℃, and Zone 4 205-210℃; the forming die temperature is set at 205-210℃; the vacuum degree of the vacuum sizing water tank is controlled at -0.04 to -0.06 MPa, and the cooling water temperature is controlled at 15-20℃.

[0037] By adopting the above technical solution, the single-screw extruder uses a stepped heating mode from 180-185℃ to 205-210℃, allowing the modified masterbatch to gradually absorb heat and melt, avoiding premature melting of the material and uneven plasticization. The molding die temperature is matched with the highest barrel temperature to reduce melt flow resistance. The sizing tank with a vacuum degree of -0.04 to -0.06MPa keeps the semi-molten outer wall of the pipe tightly against the inner wall of the sizing sleeve, and the cooling water at 15-20℃ removes heat from the pipe, promoting the crystallization and solidification of polyethylene molecular chains on the surface of the pipe, ensuring the outer diameter and ring stiffness of the pipe.

[0038] This invention provides a high-strength cable protection pipe for communication and its manufacturing process. It has the following beneficial effects:

[0039] 1. This invention introduces non-polar polyethylene long molecular chains into the surface of inorganic fillers by adding maleic anhydride-grafted polyethylene to the raw materials. This increases the interfacial compatibility between wollastonite and the high-density polyethylene matrix, reduces microscopic defects on the filler surface, and enables the matrix to transfer stress to the rigid filler when under stress, thereby improving the tensile strength and stiffness of the pipe.

[0040] 2. This invention prepares a side-feed liquid suspension slurry by compounding epoxidized soybean oil, pentaerythritol, and zinc stearate, and injects it into the polymer melt in the middle section of the twin-screw extruder. This avoids the feed rate fluctuation problem that is easily caused when traditional solid lubricants are added at the main feed port. After the liquid carrier enters the melt, it reduces the apparent viscosity and absorbs the heat generated by mechanical shearing. At the same time, it disperses the suspended solid particles with the flow of the melt, maintaining the continuity and stability of the pipe extrusion process.

[0041] 3. This invention employs a two-step process combining twin-screw reactive extrusion and single-screw secondary molding. In the twin-screw extrusion stage, vacuum degassing is activated to extract small-molecule water and volatiles generated during the reaction. In the single-screw molding stage, stepped heating and vacuum sizing cooling are used to avoid uneven plasticization caused by premature melting of materials, prevent porosity defects on the pipe wall, and promote the crystallization and solidification of polyethylene molecular chains on the pipe surface, ensuring the density and outer diameter accuracy of the finished product. Attached Figure Description

[0042] Figure 1 This is a magnified spectral image of the carbonyl stretching vibration region, representing the chemical structure evolution characterization of this invention.

[0043] Figure 2 This is a magnified spectral image of the characteristic region of the epoxy group, representing the chemical structure evolution characterization of this invention.

[0044] Figure 3 Figure 1 shows the tensile stress-strain curve of the high-strength cable protection pipe sample for communication of the present invention. Figure 2 shows the complete tensile stress-strain curve of the present invention, and Figure 3 shows a magnified curve of the low strain region of the present invention. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, preparation examples, embodiments, comparative examples, and test examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Preparation Examples 1-3:

[0047] Preparation Example 1:

[0048] This preparation example provides a side-fed liquid suspension slurry, including the following steps:

[0049] 2.0 kg of epoxidized soybean oil (epoxidation value of 6.0%) was added to a batching tank equipped with a circulation loop and a high-shear homogenizer at room temperature of 20°C.

[0050] While stirring, add 0.05 kg pentaerythritol (particle size D50 of 10 μm, moisture content less than or equal to 0.05%) and 0.2 kg zinc stearate to the mixing tank;

[0051] Turn on the high-shear homogenizer, set the speed to 1000 rpm, and continue processing for 20 minutes to obtain a side-feed liquid suspension slurry.

[0052] Preparation Example 2:

[0053] This preparation example provides a side-fed liquid suspension slurry, including the following steps:

[0054] In a batching tank equipped with a circulation loop and a high-shear homogenizer, 2.5 kg of epoxidized soybean oil (epoxidation value of 6.2%) was added at room temperature of 22°C.

[0055] While stirring, add 0.10 kg pentaerythritol (particle size D50 of 12 μm, moisture content less than or equal to 0.05%) and 0.3 kg zinc stearate to the mixing tank;

[0056] Turn on the high-shear homogenizer, set the speed to 1250 rpm, and process for 25 minutes to obtain a side-feed liquid suspension slurry.

[0057] Preparation Example 3:

[0058] This preparation example provides a side-fed liquid suspension slurry, including the following steps:

[0059] In a batching tank equipped with a circulation loop and a high-shear homogenizer, 3.0 kg of epoxidized soybean oil (epoxidation value of 6.5%) was added at room temperature of 25°C.

[0060] While stirring, add 0.15 kg pentaerythritol (particle size D50 of 15 μm, moisture content less than or equal to 0.05%) and 0.4 kg zinc stearate to the mixing tank;

[0061] Turn on the high-shear homogenizer, set the speed to 1500 rpm, and continue processing for 30 minutes to obtain a side-feed liquid suspension slurry.

[0062] Examples 1-3:

[0063] Example 1:

[0064] This embodiment provides a manufacturing process for a high-strength cable protection tube for communication, including the following steps:

[0065] 15.0 kg of needle-shaped wollastonite powder was placed in an oven and dried with hot air at 105℃ for 2 hours.

[0066] 100.0 kg of high-density polyethylene, 15.0 kg of pre-dried needle-shaped wollastonite powder, 5.0 kg of maleic anhydride-grafted polyethylene, 0.20 kg of antioxidant 1010 (i.e., pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]) and 0.20 kg of antioxidant 168 (i.e., tris(2,4-di-tert-butylphenyl) phosphite) were added to a high-speed mixer. The mixer was started, and the speed was set to 300 rpm. The mixture was then blended at room temperature for 3 minutes. The blended material was then transferred to a loss-in-weight feeder and fed into the main feed port of a co-rotating twin-screw extruder with a length-to-diameter ratio of 40.

[0067] Set the screw speed of the co-rotating twin-screw extruder to 300 rpm. Set the barrel temperature of the co-rotating twin-screw extruder in zones 1-4 to 200℃.

[0068] The barrel temperature of the co-rotating twin-screw extruder in zones 5-8 is set to 185°C. When the polymer melt reaches zone 5, the liquid injection pump is started to uniformly and continuously inject the side-feed liquid suspension slurry prepared in Preparation Example 1, which is stirred and refluxed online in the mixing tank at a speed of 60 rpm, into the polymer melt in the co-rotating twin-screw extruder.

[0069] The barrel temperature of the co-rotating twin-screw extruder in zones 9-10 was set to 190℃, and the vacuum exhaust port was opened, with the exhaust vacuum controlled at -0.08MPa. After the polymer melt was extruded through the die of the co-rotating twin-screw extruder, it entered a room-temperature water bath at 20℃ for cooling, forming strands, and then pelletizing to obtain modified masterbatch. The obtained modified masterbatch was placed in a hot air drying system and dried at 80℃ for 2 hours.

[0070] The dried modified masterbatch is fed into a single-screw pipe extruder with a length-to-diameter ratio of 30. The temperatures of the heating zones of the single-screw pipe extruder barrel are set sequentially as follows: Zone 1 180℃, Zone 2 190℃, Zone 3 200℃, and Zone 4 205℃.

[0071] The temperature of the forming die of the single-screw pipe extruder is set to 205℃. After the polymer melt is extruded through the forming die to form a pipe, it enters a vacuum sizing tank for cooling and shaping. The vacuum degree of the sizing tank is controlled at -0.04MPa, and the cooling water temperature is controlled at 15℃. After cooling and shaping, the pipe is drawn and cut to obtain a high-strength cable protection pipe for communication.

[0072] Example 2:

[0073] This embodiment provides a manufacturing process for a high-strength cable protection tube for communication, including the following steps:

[0074] 17.5 kg of needle-shaped wollastonite powder was placed in an oven and dried with hot air at 112°C for 3 hours.

[0075] 100.0 kg of high-density polyethylene, 17.5 kg of pre-dried needle-shaped wollastonite powder, 6.5 kg of maleic anhydride-grafted polyethylene, 0.25 kg of antioxidant 1010, and 0.25 kg of antioxidant 168 were added to a high-speed mixer. The mixer was started, and the speed was set to 400 rpm. The mixture was then blended at room temperature for 4 minutes. The blended material was then transferred to a loss-in-weight feeder and fed into the main feed port of a co-rotating twin-screw extruder with a length-to-diameter ratio of 40.

[0076] Set the screw speed of the co-rotating twin-screw extruder to 350 rpm. Set the barrel temperature of the co-rotating twin-screw extruder in zones 1-4 to 205℃.

[0077] The barrel temperature of the co-rotating twin-screw extruder in zones 5-8 was set to 187°C. When the polymer melt reached zone 5, the liquid injection pump was started to uniformly and continuously inject the side-feed liquid suspension slurry prepared in Preparation Example 2, which was stirred and refluxed online in the mixing tank at a speed of 80 rpm, into the polymer melt in the co-rotating twin-screw extruder.

[0078] The barrel temperature of the co-rotating twin-screw extruder in zones 9-10 was set to 192℃, and the vacuum exhaust port was opened, with the exhaust vacuum controlled at -0.085MPa. After the polymer melt was extruded through the die of the co-rotating twin-screw extruder, it entered a room temperature water bath at 25℃ for cooling, forming strands, and then pelletizing to obtain modified masterbatch. The obtained modified masterbatch was placed in a hot air drying system and dried at 82℃ for 3 hours.

[0079] The dried modified masterbatch was fed into a single-screw pipe extruder with a length-to-diameter ratio of 32. The temperatures of the heating zones of the single-screw pipe extruder barrel were set sequentially as follows: Zone 1 182℃, Zone 2 192℃, Zone 3 202℃, and Zone 4 207℃.

[0080] The temperature of the forming die of the single-screw pipe extruder is set to 207℃. After the polymer melt is extruded through the forming die to form a pipe, it enters a vacuum sizing tank for cooling and shaping. The vacuum degree of the sizing tank is controlled at -0.05MPa, and the cooling water temperature is controlled at 17℃. After cooling and shaping, the pipe is drawn and cut to obtain a high-strength cable protection pipe for communication.

[0081] Example 3:

[0082] This embodiment provides a manufacturing process for a high-strength cable protection tube for communication, including the following steps:

[0083] 20.0 kg of needle-shaped wollastonite powder was placed in an oven and dried with hot air at 120°C for 4 hours.

[0084] 100.0 kg of high-density polyethylene, 20.0 kg of pre-dried needle-shaped wollastonite powder, 8.0 kg of maleic anhydride-grafted polyethylene, 0.30 kg of antioxidant 1010, and 0.30 kg of antioxidant 168 were added to a high-speed mixer. The mixer was started, and the speed was set to 500 rpm. The mixture was then blended at room temperature for 5 minutes. The blended material was then transferred to a loss-in-weight feeder and fed into the main feed port of a co-rotating twin-screw extruder with a length-to-diameter ratio of 40.

[0085] Set the screw speed of the co-rotating twin-screw extruder to 400 rpm. Set the barrel temperature of the co-rotating twin-screw extruder in zones 1-4 to 210℃.

[0086] The barrel temperature of the co-rotating twin-screw extruder in zones 5-8 was set to 190°C. When the polymer melt reached zone 5, the liquid injection pump was started to uniformly and continuously inject the side-feed liquid suspension slurry prepared in Preparation Example 3, which was stirred and refluxed online in the mixing tank at a speed of 100 rpm, into the polymer melt in the co-rotating twin-screw extruder.

[0087] The barrel temperature of the co-rotating twin-screw extruder in zones 9-10 was set to 195℃, and the vacuum exhaust port was opened, with the exhaust vacuum controlled at -0.09MPa. After the polymer melt was extruded through the die of the co-rotating twin-screw extruder, it entered a room-temperature water bath at 30℃ for cooling, forming strands, and then pelletizing to obtain modified masterbatch. The obtained modified masterbatch was placed in a hot air drying system and dried at 85℃ for 4 hours.

[0088] The dried modified masterbatch is fed into a single-screw pipe extruder with an aspect ratio of 33. The temperatures of the heating zones of the single-screw pipe extruder barrel are set sequentially as follows: Zone 1 185℃, Zone 2 195℃, Zone 3 205℃, and Zone 4 210℃.

[0089] The temperature of the forming die of the single-screw pipe extruder is set to 210℃. After the polymer melt is extruded through the forming die to form a pipe, it enters a vacuum sizing tank for cooling and shaping. The vacuum degree of the sizing tank is controlled at -0.06MPa, and the cooling water temperature is controlled at 20℃. After cooling and shaping, the pipe is drawn and cut to obtain a high-strength cable protection pipe for communication.

[0090] Comparative Examples 1-6:

[0091] Comparative Example 1:

[0092] Compared with Example 2, the difference is that maleic anhydride-grafted polyethylene is not added to the materials fed into the high-speed mixer for blending; all other aspects are the same.

[0093] Comparative Example 2:

[0094] The difference from Example 2 is that pentaerythritol is not added to the mixing tank in the step of preparing the side-feed liquid suspension slurry; all other steps are the same.

[0095] Comparative Example 3:

[0096] Compared with Example 2, the differences are as follows: no side-feed liquid suspension slurry is prepared, epoxidized soybean oil is not used, 0.10 kg pentaerythritol and 0.3 kg zinc stearate are directly added to the high-speed mixer along with other raw materials such as high-density polyethylene for blending, and the step of injecting liquid using a liquid injection pump in zone 5 of the co-rotating twin-screw extruder is omitted, while the rest are the same.

[0097] Comparative Example 4:

[0098] Compared with Example 2, the difference is that: no side-feed liquid suspension slurry is prepared; instead, 2.5 kg of epoxidized soybean oil, 0.10 kg of pentaerythritol, and 0.3 kg of zinc stearate are added together with high-density polyethylene and all other raw materials in a high-speed mixer for blending. All blended materials are fed into the main feed port of a co-rotating twin-screw extruder through a loss-in-weight feeder. The step of injecting liquid using a liquid injection pump in zone 5 of the co-rotating twin-screw extruder is omitted. All other steps are the same.

[0099] Comparative Example 5:

[0100] Compared with Example 2, the difference is that the barrel temperature of the co-rotating twin-screw extruder in zones 5-8 is set to 205°C, which is the same as the temperature setting in zones 1-4, and the rest are the same.

[0101] Comparative Example 6:

[0102] Compared with Example 2, the difference is that in the step of preparing the side-feed liquid suspension slurry, the mass of pentaerythritol added to the mixing tank is 1.0 kg, and the rest are the same.

[0103] Test Example 1-3:

[0104] Test Example 1:

[0105] This test example characterizes the chemical structure evolution of the modified masterbatch, and verifies the transformation of functional groups during reactive extrusion using Fourier transform infrared spectroscopy. The specific operation process is as follows:

[0106] Take 2.0 g of each of the modified masterbatch particles prepared in Example 2, Comparative Examples 2, 3, and 4, and place them on a two-roll micro open mill for plasticizing and mixing at 190°C for 2 minutes.

[0107] The plasticized material is transferred to a hot press and held at 190°C and 10MPa pressure for 3 minutes to form a film sample with a thickness of about 0.1 mm. The sample is then cooled and shaped in a cold press.

[0108] The thin film sample was scanned in transmission mode using a Fourier transform infrared spectroscopy (FTIR) instrument, with the scanning wavenumber range set to 4000 to 400 cm⁻¹. -1 The spectral resolution was set to 4cm. -1 The number of background air scans and sample measurement scans were both set to 32.

[0109] After the spectral data acquisition was completed, the raw spectrum was baseline calibrated using spectral processing software, with a baseline of 1462 cm⁻¹ selected. -1 The methylene bending vibration peak at a specific wavenumber was used as an internal standard reference peak to normalize the absorbance of each spectrum. Finally, the relative absorbance values ​​at a specific target wavenumber were extracted for comparative analysis.

[0110] Table 1. Relative absorbance of infrared characteristic peaks of different modified masterbatch samples

[0111] Sample 1780 cm -1 (anhydride ring) 1735 cm -1 (ester bond) 1710 cm -1 (free carboxyl group) 825 cm -1 (epoxy group) Example 2 0.014 0.187 0.009 0.005 Comparative Example 2 0.141 0.008 0.004 0.126 Comparative Example 3 0.023 0.106 0.098 0.002 Comparative Example 4 0.068 0.094 0.051 0.063

[0112] Test conclusion:

[0113] Combined with Table 1 and Figure 1 and Figure 2 The data showed that wollastonite was present in the tested thin film, and the baseline of the spectrum exhibited a characteristic of curving towards lower wavenumbers. After removing this background interference, the comparison revealed that the sample in Example 2 showed better light scattering at 1780 cm⁻¹. -1 The relative absorbance of the anhydride ring at this location is 0.014, and it is at 1735 cm⁻¹. -1 The relative absorbance of the ester bond at that location was 0.187, and at... Figure 1 A broadened ester bond absorption peak appears at 1710 cm⁻¹. -1 The peak signal representing the free carboxyl group is close to the baseline fluctuation level. This indicates that a cascade ring-opening reaction occurred between maleic anhydride-grafted polyethylene, pentaerythritol, and epoxidized soybean oil. Comparative Example 2, due to the absence of pentaerythritol, shows a peak signal at 1780 cm⁻¹ in Table 1. -1 The relative absorbance at that location is 0.141. Figure 2 825cm -1 The presence of unconsumed epoxy characteristic peaks indicates that the coupling between maleic anhydride-grafted polyethylene and epoxidized soybean oil is minimal in the absence of pentaerythritol mediation.

[0114] Examining the spectral data of Comparative Example 3 allows for further observation of the evolution pathway of the free carboxyl groups in the system. Comparative Example 3 did not contain epoxidized soybean oil; the hydroxyl groups of pentaerythritol underwent a half-esterification reaction with maleic anhydride-grafted polyethylene. Since the free carboxyl groups were not consumed, the spectral data of Comparative Example 3 in Table 1 at 1710 cm⁻¹... -1 The relative absorbance at this location is 0.098, and at... Figure 1 The peaks of the middle and adjacent ester bonds overlap to form a shoulder peak structure. Residual free acidic groups exist in the finished pipe material, which can easily catalyze the thermal-oxidative degradation of the matrix. The epoxy groups on the epoxidized soybean oil molecule consume free carboxyl groups; the disappearance of the carboxyl signal and the accompanying increase in the ester bond signal in Example 2 confirm this reaction process.

[0115] In Comparative Example 4, all reactants were fed into the main feed inlet of a co-rotating twin-screw extruder. The components simultaneously entered the molten state and came into contact in the high-temperature region at the front of the extruder. Table 1 shows the relative absorbances of the anhydride ring, ester bond, free carboxyl group, and epoxy group in Comparative Example 4 as 0.068, 0.094, 0.051, and 0.063, respectively. Due to the overlap of adjacent characteristic peaks... Figure 1The carbonyl region in Comparative Example 4 exhibits an irregular, broad absorption band. Pre-introduction of pentaerythritol and epoxidized soybean oil weakens the thermodynamic driving force for the migration of maleic anhydride-grafted polyethylene to wollastonite. Epoxidized soybean oil undergoes a side reaction under strong shear, blocking the construction of local micro-bridging networks. Comparison of infrared spectra of different samples demonstrates the influence of using a liquid injection pump to feed liquid suspension slurry into the fifth zone of a co-rotating twin-screw extruder and segmented barrel temperature settings on the reaction mechanism.

[0116] Test Example 2:

[0117] This test example involves combined rheological and dynamic thermomechanical behavior testing of the modified masterbatch and high-strength cable protection tubing for communication applications to verify the evolution of the system's internal microstructure. The specific operational procedure is as follows:

[0118] The modified masterbatches prepared in Example 2 and Comparative Examples 1, 4, and 6 were placed in a vacuum oven and dried at 80°C for 4 hours to remove moisture interference. The dried modified masterbatches were then hot-pressed into 1.5 mm thick discs on a flat vulcanizing machine at 190°C and 15 MPa pressure, and subsequently cut into disc samples using a 25 mm diameter cutter for later use.

[0119] Dynamic frequency scanning tests were performed on the disk samples using a rotational rheometer. A 25 mm parallel plate fixture was used with a spacing of 1.2 mm. The test temperature was kept constant at 190 °C, and the angular frequency scanning range was set from 0.1 to 100 rad / s under a constant strain of 1%. The changes in complex viscosity and storage modulus with angular frequency were recorded.

[0120] Select the high-strength cable protection pipe for communication from the corresponding test batch, cut it along the pipe axis and machine it into a rectangular strip with dimensions of 35mm×10mm×2mm.

[0121] Temperature scanning tests were performed on the specimens using a dynamic thermomechanical analyzer in double cantilever bending mode. The test frequency was set to 1 Hz, and the ratio of static force to dynamic force was maintained at 1.2 to keep the specimens under tension. The temperature scanning range was set to -140℃ to 20℃, and the heating rate was controlled at 3℃ / min. The loss tangent curve near the glass transition region of the amorphous region of polyethylene was extracted, and the peak temperature and peak half-width at half-maximum (FWHM) were calculated.

[0122] Table 2. Rheological characteristics and dynamic thermomechanical parameters of different samples

[0123] Sample Complex viscosity at 0.1 rad / s (Pa s) Storage modulus at 0.1 rad / s (Pa) Tan delta peak temperature (°C) Tan delta peak half-height width (°C) Example 2 41258 8416 -108.6 21.3 Comparative Example 1 14892 1153 -116.2 12.8 Comparative Example 4 29104 4521 -112.4 15.6 Comparative Example 6 586410 175890 -105.1 17.2

[0124] Test conclusion:

[0125] According to the data in Table 2, the rheological behavior of the polymer composite material is sensitive to its internal microstructure. The response parameters at low frequencies can reflect the physical or chemical entanglement state of the acicular wollastonite powder and the high-density polyethylene phase boundary. In Example 2, at a low frequency of 0.1 rad / s, its complex viscosity reached 41258 Pa·s, and its storage modulus was 8416 Pa, showing an increase compared to Comparative Example 1 (complex viscosity 14892 Pa·s, storage modulus 1153 Pa) without maleic anhydride grafted polyethylene. The difference in eigenvalues ​​at the 0.1 rad / s frequency reflects the reconstructed state of the topological network within the system. This increase in modulus and yielding characteristic of complex viscosity in the low-frequency region is a rheological signal indicating the formation of a percolation network within the polymer matrix or anchoring at the phase boundary. In Example 2, pentaerythritol bridged adjacent maleic anhydride grafted polyethylene chains on the surface of the acicular wollastonite powder, constructing a local topological network that restricted the slippage of macromolecular chains in the long relaxation time domain.

[0126] Comparative Example 6, with the addition of excess pentaerythritol, broke through the ratio conditions for local bridging of interfacial microregions, inducing bulk crosslinking of maleic anhydride-grafted polyethylene matrix macromolecular segments. Table 2 shows that the low-frequency complex viscosity of Comparative Example 6 increased to 586410 Pa·s. This crosslinking leads to reduced melt flowability during extrusion processing, making the surface of high-strength cable protection pipes for communication prone to melt fracture and rough texture. Example 2 limited the degree of crosslinking to the substoichiometric level, balancing interfacial strengthening and overall processability. Comparative Example 4, with a different feeding sequence, had a complex viscosity of 29104 Pa·s and a storage modulus of 4521 Pa at 0.1 rad / s. Its rheological data were between those of Comparative Example 1 and Example 2, indicating that feeding the raw materials uniformly into the main feed port of the co-rotating twin-screw extruder disrupted the interfacial polar enrichment process, resulting in a randomly distributed bridging structure.

[0127] Rheological data revealed the rigid constraints of the network, and combined with dynamic thermomechanical analysis, it was possible to track the energy dissipation of macromolecular segments at specific temperatures. The extracted dissipation peak parameters revealed the relaxation capability of the interfacial microenvironment. In Table 2, the full width at half maximum (FWHM) of the loss tangent peak in Example 2 broadened from 12.8°C in Comparative Example 1 to 21.3°C, and the peak temperature shifted towards the higher temperature side to -108.6°C. Because epoxidized soybean oil participated in the ring-opening reaction, groups containing long aliphatic chains were grafted into the network on the inorganic surface. These spacer arms acted as interfacial stress buffer layers, increasing the opportunities for intramolecular friction and conformational transformation under alternating stress, resulting in a broad relaxation time distribution for the polymer segments near the phase interface, manifested as a broadening of the damping peak. Comparative Example 4, lacking a flexible modification layer, had an incomplete dissipation structure, with a FWHM of 15.6°C and a loss tangent peak temperature of -112.4°C, lower than Example 2. By combining the rigid constraints of bridging with the modification of epoxidized soybean oil, a buffer transition layer with mechanical transmission and stress dissipation functions is constructed between acicular wollastonite powder and high-density polyethylene.

[0128] Test Example 3:

[0129] This test case compares the comprehensive application performance of high-strength cable protection pipes and modified masterbatches for communication applications, including mechanical property and processing fluidity tests, to verify the impact of interface topology modification on the macroscopic properties of the materials. The specific operational process is as follows:

[0130] High-strength communication cable protection pipes extruded from Examples 1 to 3 and Comparative Examples 1 to 6 were selected. Sections of these pipes were cut and machined into standard Type 1 notched specimens using a CNC milling machine according to GB / T 18743.1-2022 standard. The notch bottom radius was set to 0.25 mm. After conditioning the specimens in an environment of 23°C and 50% relative humidity for 48 hours, a simply supported beam notched impact strength test was performed using a pendulum impact testing machine.

[0131] A 300mm long sample of high-strength cable protection pipe for communication applications was taken and its ring stiffness was tested on a computer-controlled electronic universal testing machine according to the GB / T9647-2015 standard. The sample was placed horizontally between two parallel steel plates, and the compression speed of the plates was set to 10mm / min. The load value corresponding to the vertical deformation of the sample's inner diameter reaching 3% of the original inner diameter of the high-strength cable protection pipe was recorded, and then the ring stiffness of the high-strength cable protection pipe was calculated.

[0132] A type 1B (machined dumbbell type) tensile specimen conforming to GB / T1040.2-2022 standard was cut axially from the wall of a high-strength cable protection conduit for communication. The gauge length was 10 mm wide. The specimen was clamped on an electronic universal testing machine, and the tensile speed was set to 50 mm / min. The load and displacement changes during the tensile process were recorded, and the tensile yield strength and fracture behavior data were extracted.

[0133] The dried modified masterbatches prepared in Examples 1 to 3 and Comparative Examples 1 to 6 were collected, and the melt flow rate was tested on a melt flow rate tester according to GB / T3682.1-2018 standard. The inner diameter of the test die was 2.095 mm, the barrel temperature was kept constant at 190 °C, and the total nominal load of the piston and weights was set to 5.0 kg. The mass of the extruded melt was recorded within a specific time period.

[0134] Table 3. Test data on mechanical properties and processing fluidity of different samples

[0135] Sample Charpy notched impact strength (kJ / m 2 )]> Ring stiffness (kN / m 2 )]> Tensile yield strength (MPa) Melt flow rate (g / 10 min) Example 1 25.4 8.8 25.8 2.52 Example 2 28.6 9.1 26.9 2.24 Example 3 27.1 9.4 26.2 1.86 Comparative Example 1 10.4 7.2 20.3 3.51 Comparative Example 2 15.6 7.8 23.1 2.84 Comparative Example 3 13.2 8.9 22.5 1.57 Comparative Example 4 18.4 8.1 24.3 2.11 Comparative Example 5 16.5 7.9 22.8 1.25 Comparative Example 6 11.8 9.6 29.1 0.18

[0136] Test conclusion:

[0137] According to the data in Table 3, the reinforcing effect of inorganic fillers in the polymer matrix is ​​limited by interfacial debonding and stress concentration. Based on the data analysis in Table 3, the high-strength cable protection pipes for communication prepared in Examples 1 to 3 show better overall performance than the comparative group. The notched impact strength of the simply supported beam of the high-strength cable protection pipe for communication prepared in Example 2 is 28.6 kJ / m. 2 The tensile yield strength is 26.9 MPa, and the melt flow rate is 2.24 g / 10 min. Figure 3 This is a tensile stress-strain curve of a high-strength cable protection pipe sample for communication according to the present invention. To avoid excessive overlap of multiple sets of data curves and to clearly demonstrate the typical mechanical response mechanism, Figure 3 Four representative sets of sample curves were extracted and compared for display. Figure 3 The subplot in (a) is the complete tensile stress-strain curve. Figure 3 The subplot in (b) is a magnified curve of the low strain region. The solid lines of each color in the figure correspond to the high-strength cable protection pipe samples for communication prepared in Example 2, Comparative Example 1, Comparative Example 4 and Comparative Example 6, respectively. The horizontal axis is the engineering strain and the vertical axis is the engineering stress.

[0138] Based on comparative data analysis, the molecular topology of the interface layer determines the initiation and propagation path of microcracks. In Comparative Example 1, without the introduction of maleic anhydride-grafted polyethylene, there is physical adsorption between the needle-like wollastonite powder and high-density polyethylene, resulting in interfacial delamination under external load impact. Table 3 shows that the notched impact strength of Comparative Example 1 is 10.4 kJ / m. 2 , combinedFigure 3 As shown in the tensile curve of Comparative Example 1 in subgraph (b), Comparative Example 1 fractured after reaching a relatively low stress level, without undergoing yielding and cold tensile stages, exhibiting brittle fracture characteristics. Comparative Example 2 lacks the bridging effect of pentaerythritol, and Comparative Example 3 lacks the modification of epoxidized soybean oil, resulting in a decrease in the corresponding mechanical properties. Based on the data in Table 3, the ring stiffness of Comparative Example 3 is 8.9 kN / m. 2 The impact strength decreased to 13.2 kJ / m. 2 A single semi-esterification reaction or a rigid anchor lacking spacer buffers cannot dissipate the failure strain energy, and the interface rigidity easily induces local stress concentration upon impact. (Comparison) Figure 3 The curve features in subgraph (a) show that the curve in Example 2 has a large integral area, and the stretching plateau region of the curve indicates that the buffer transition layer constructed within the system absorbs deformation energy during the stretching process.

[0139] Regarding the preparation process and reaction degree control, in Comparative Example 4, the materials were mixed in a mixer and then fed into the main feed port, disrupting the physical process of preferential migration and enrichment of polar molecules into the inorganic phase. Comparative Example 5 did not set a temperature gradient, making it difficult to control the degree of ring-opening reaction. The overall performance of the high-strength cable protection pipes for communication prepared in Comparative Examples 4 and 5 was at a moderate level, indicating that without specific spatial confinement and microenvironment, it was impossible to construct the phase interface structure of the buffer transition layer. After adding excess pentaerythritol, three-dimensional cross-linking occurred within the system. The tensile yield strength of Comparative Example 6 in Table 3 was 29.1 MPa. Figure 3 Analysis of the corresponding curves in subplot (b) shows that Comparative Example 6 exhibits a larger initial slope, but the material fractures prematurely. Table 3 shows that the melt flow rate of Comparative Example 6 decreases to 0.18 g / 10 min, and the melt, having lost its fluidity, is prone to melt fracture during extrusion. Maintaining a substoichiometric ratio plays a crucial role in preserving the material's molding and processing capabilities.

Claims

1. A high-strength cable protection pipe for communication, characterized in that, Made from the following ingredients in parts by weight: High-density polyethylene: 100 parts; Needle-shaped wollastonite powder: 15-20 parts; Maleic anhydride-grafted polyethylene: 5-8 parts; Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]: 0.2-0.3 parts; Tris(2,4-di-tert-butylphenyl) phosphite: 0.2-0.3 parts; Side-fed liquid suspension slurry: 2.25-3.55 parts; The side-feed liquid suspension slurry contains epoxidized soybean oil, pentaerythritol, and zinc stearate as raw materials.

2. The high-strength cable protection pipe for communication according to claim 1, characterized in that, The pentaerythritol has a particle size D50 of 10-15 μm and a water content of less than or equal to 0.05%. The epoxy value of the epoxidized soybean oil is 6.0%-6.5%.

3. The high-strength cable protection pipe for communication according to claim 1, characterized in that, The preparation process of the side-feed liquid suspension slurry includes: adding 2.0-3.0 parts by weight of the epoxidized soybean oil to a batching tank equipped with a circulation loop and a high-shear homogenizer; adding 0.05-0.15 parts by weight of the pentaerythritol and 0.2-0.4 parts by weight of the zinc stearate while stirring; turning on the high-shear homogenizer; setting the rotation speed to 1000-1500 rpm; and continuing the process for 20-30 minutes.

4. A manufacturing process for a high-strength cable protection pipe for communication, characterized in that, The application of the high-strength cable protection conduit for communication as described in any one of claims 1-3 includes the following steps: The needle-shaped wollastonite powder was placed in an oven and dried with hot air. High-density polyethylene, pre-dried needle-shaped wollastonite powder, maleic anhydride-grafted polyethylene, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite are put into a high-speed mixer, the stirring is turned on and the mixture is stirred and mixed, and the mixed material is fed into the main feed port of a co-rotating twin-screw extruder. The fed material is heated and melted in the co-rotating twin-screw extruder to form a polymer melt, which is then extruded forward. During the forward extrusion of the polymer melt, a liquid injection pump is started to continuously inject the side-feed liquid suspension slurry into the polymer melt in the co-rotating twin-screw extruder for mixing. Open the vacuum exhaust port to exhaust the mixed polymer melt; After the venting is completed, the polymer melt is extruded through the die of the co-rotating twin-screw extruder to form a strip. The strip is then cooled, and the cooled strip is pelletized to obtain modified masterbatch. The modified masterbatch is then dried with hot air. The dried modified masterbatch is fed into a single-screw pipe extruder and heated to melt, forming a pipe polymer melt. The pipe polymer melt is extruded through the forming die of the single-screw pipe extruder to form a pipe. The pipe is then introduced into a vacuum sizing tank for cooling and shaping. The cooled and shaped pipe is then pulled and cut to obtain a high-strength cable protection pipe for communication.

5. The preparation process according to claim 4, characterized in that, The hot air drying temperature is 105-120℃, and the time is 2-4 hours.

6. The preparation process according to claim 4, characterized in that, The high-speed mixer is set to a speed of 300-500 rpm and is mixed at room temperature for 3-5 minutes. The blended material is transferred into a loss-in-weight feeder and then fed into the main feed port of the co-rotating twin-screw extruder.

7. The preparation process according to claim 4, characterized in that, The co-rotating twin-screw extruder has a length-to-diameter ratio of 40 and a screw speed of 300-400 rpm; The barrel of the co-rotating twin-screw extruder is divided into 10 temperature control zones along the forward extrusion direction of the polymer melt, wherein the barrel temperature of zones 1-4 is 200-210℃, the barrel temperature of zones 5-8 is 185-190℃, and the barrel temperature of zones 9-10 is 190-195℃. The side-feed liquid suspension slurry is injected when the polymer melt reaches the fifth zone.

8. The preparation process according to claim 4, characterized in that, Before the side-feed liquid suspension slurry is injected into the co-rotating twin-screw extruder, it is stirred at a speed of 60-100 rpm in the mixing tank and refluxed online.

9. The preparation process according to claim 4, characterized in that, The exhaust vacuum degree of the vacuum exhaust port is controlled between -0.08 and -0.09 MPa; The cooling of the strip-shaped material is achieved by introducing the strip-shaped material into a room temperature water bath with a water temperature of 20-30℃ for cooling. The modified masterbatch is dried at 80-85℃ for 2-4 hours.

10. The preparation process according to claim 4, characterized in that, The length-to-diameter ratio of the single-screw tube extruder is 30-33; The barrel heating zone of the single screw pipe extruder includes four zones, with the temperatures set sequentially as follows: Zone 1 180-185℃, Zone 2 190-195℃, Zone 3 200-205℃, and Zone 4 205-210℃. The temperature of the molding die is set to 205-210℃; The vacuum degree of the vacuum sizing tank is controlled between -0.04 and -0.06 MPa, and the cooling water temperature is controlled between 15 and 20°C.

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