Production method of rare earth antibacterial anti-impact anti-scale PP-R pipe

Abstract

The invention discloses a production method of a rare earth bacteriostatic anti-impact anti-scale PP-R pipe, which comprises the following steps: rare earth grinding treatment, master batch preparation, raw material blending and extrusion molding.According to the production method, cerium oxide, lanthanum oxide and zinc oxide are refined to a submicron level through multi-stage grinding, and the cerium oxide and the lanthanum oxide after multi-stage grinding are in close contact with an interface, so that the service life of the PP-R pipe is prolonged, and the service life of the PP-R pipe is prolonged. The surface active sites of cerium oxide, lanthanum oxide and zinc oxide are high, electrons or ions are effectively transmitted, the synergistic antibacterial and catalytic performance is enhanced, zinc oxide subjected to multi-stage grinding enables the specific surface area to be large, Zn is fully released, the antibacterial efficiency is improved, and a silane coupling agent is added in the accurate grinding process, so that particles of cerium oxide, lanthanum oxide and zinc oxide are continuously crushed, and the antibacterial effect is improved. Newly generated surface active sites can be timely combined with a silane coupling agent so as to be fully mixed and coated, and then through the cooperation of the steps of master batch preparation, raw material blending and extrusion molding, the antibacterial performance, the anti-impact performance, the anti-scaling performance and the like of the PP-R pipe are improved.

Description

Technical Field

[0001] The invention relates to the field of polymer materials, and in particular to a method for producing a rare earth antibacterial, impact-resistant and scale-resistant PP-R pipe. Background Art

[0002] Random copolymer polypropylene (PP-R) pipes are widely used in building water supply and drainage, industrial fluid transportation, and other fields due to their corrosion resistance, convenient hot-melt connection, and reasonable cost. However, traditional PP-R pipes still have significant performance shortcomings in actual use: First, the inner wall of the pipe is prone to bacterial growth (such as Legionella and E. coli), causing water pollution and threatening human health; second, the impact resistance is insufficient in low-temperature environments, making it prone to rupture due to external impact during transportation, installation, and use; third, after long-term use, the inner wall of the pipe is prone to scaling, reducing fluid transportation efficiency and increasing maintenance costs. Existing research on improving the performance of PP-R pipes has primarily focused on adding single functional additives or simple compounding. For example, while silver-based antimicrobial agents can achieve antibacterial effects, silver ions are prone to migration, are costly, and pose potential ecological risks. While adding inorganic fillers such as calcium carbonate and talc can improve rigidity, they can significantly reduce impact resistance. Traditional masterbatches have low molecular weights and are prone to precipitation. Furthermore, insufficient control over the dispersion of functional fillers leads to significant particle agglomeration, making it difficult to achieve synergistic improvements in multiple properties. At the same time, existing rare earth-modified PP-R pipe technology still has many drawbacks. First, the coarse particle size of rare earth oxides makes it difficult to form a close contact interface, resulting in ineffective electron or ion transfer between the active sites on the surfaces of the two, weakening their synergistic antibacterial or catalytic properties. The coarse particle size of zinc oxide results in a small specific surface area, leading to insufficient Zn²⁺ release, low antibacterial efficiency, and weak interfacial bonding with the matrix resin, which easily induces stress concentration and reduces the impact strength of the composite material. Second, the lack of systematic collaborative design between the various components makes it difficult to simultaneously meet the comprehensive requirements of antibacterial, impact resistance, anti-fouling, and processing performance. Therefore, it is urgent to develop a new preparation process that can achieve comprehensive improvements in the performance of PP-R pipes through refined oxide treatment, multi-component collaborative modification, and molding process optimization. Therefore, it is necessary to propose a rare earth antibacterial, impact-resistant, and anti-fouling PP-R pipe and its production method. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems in the background technology and provide a production method of rare earth antibacterial, anti-impact and anti-scale PP-R pipes.

[0004] The above technical objectives of the present invention are achieved through the following technical solutions: A method for producing rare earth antibacterial, anti-impact and anti-scale PP-R pipes, comprising the following steps: S1. Grinding and Modification: Cerium oxide, lanthanum oxide, and zinc oxide are ground to submicron size using a multi-stage modified grinding device. A hydrolyzed silane coupling agent is initially added to the fine grinding chamber of the multi-stage modified grinding device for initial coating. The remaining hydrolyzed silane coupling agent is then added for full coating. The particles are then dried to form modified composite particles. S2. Masterbatch preparation: Nano-silica is mixed with PP-R resin and granulated by twin-screw extrusion; S3 raw material blending: PP-R resin, step S1 treatment of modified composite particles, polyolefin elastomer, maleic anhydride grafted polypropylene, silicone, nano-silica masterbatch and auxiliary additives premix mixing; S4. Extrusion: The blended material is extruded into a pipe blank through a twin-screw extruder. The finished pipe is then sized by vacuum, cooled in sections, and cut to obtain a finished product.

[0005] The silane coupling agent is hydrolyzed with an ethanol-water (7:3~9:1) mixed solvent. The pH is adjusted to 4~5 (acidic) or 8~9 (alkaline) according to the type of silane. The silane is slowly added dropwise and stirred for 20~40 minutes until it becomes clear to prepare an activation solution containing silanol groups. It must be used within 1~2 hours to avoid polycondensation failure due to prolonged storage and to ensure effective bonding with submicron oxides.

[0006] The present invention refines cerium oxide, lanthanum oxide, and zinc oxide to a submicron level through multi-stage grinding. After multi-stage grinding, the cerium oxide and lanthanum oxide are in close contact with each other, resulting in high surface active sites of the two, effective transfer of electrons or ions, and enhanced synergistic antibacterial and catalytic properties. The zinc oxide after multi-stage grinding has a large specific surface area, fully releases Zn²⁺, and improves antibacterial efficiency. A silane coupling agent is added during the fine grinding process, so that the particles of cerium oxide, lanthanum oxide, and zinc oxide are continuously broken, and the newly generated surface active sites can be timely combined with the silane coupling agent for sufficient mixing and coating. After the submicron particles are coated with the silane coupling agent, the specific surface area is large and the interface compatibility is excellent. The particles are uniformly dispersed to form a physically embedded "microskeleton". The organic end of the silane is entangled with the resin, and the inorganic end is bonded to the particles, forming a strong interface layer, effectively transferring loads, reducing stress concentration, and significantly improving the tensile strength and impact resistance of the PP-R pipe. When preparing the masterbatch, twin-screw extrusion granulation allows the nano-silica to be well dispersed in the resin, providing a guarantee for the anti-scaling of the pipe. During the raw material blending stage, multiple components are compounded to form a toughening system, enhancing the pipe's impact resistance. The additives also synergistically optimize overall performance. During the extrusion process, a twin-screw extruder, coupled with vacuum sizing and staged cooling, improves pipe quality, enabling continuous automated production, increasing yields, and reducing costs. This process, through the synergistic integration of various steps, enhances the antibacterial, impact, and anti-fouling properties of PP-R pipes, while also optimizing the production process, demonstrating its practical value.

[0007] When the modified composite particles are subsequently mixed with PP-R resin, etc., they can be better compatible with the resin matrix, which is equivalent to increasing the binding force between the particles and the resin, making the masterbatch more stable in the system and less likely to precipitate.

[0008] The mechanical force of the grinding beads can promote the uniform spreading of the coupling agent on the particle surface and reduce agglomeration.

[0009] Preferably, the multi-stage modified grinding device includes a frame, a cylinder, a rotating shaft, a spiral conveying blade, an anti-blocking filter mechanism, a dual-mode drive mechanism, and grinding beads arranged on the frame. The rotating shaft is arranged in the cylinder through a bearing, and the outer ring of the cylinder is arranged on the frame through a bearing. The spiral conveying blade is arranged on the rotating shaft. Two anti-blocking filter mechanisms are sequentially sleeved on the side walls of the rotating shaft to divide the cavity of the cylinder into a pre-dispersion chamber, a coarse grinding chamber, and a fine grinding chamber. The holes of the anti-blocking filter mechanism are successively reduced. The grinding beads are arranged in both the coarse grinding chamber and the fine grinding chamber. The dual-mode drive mechanism controls the cylinder and the rotating shaft to rotate forward and reverse or the rotating shaft to rotate alone.

[0010] The present invention uses a spiral conveying blade to disperse cerium oxide, lanthanum oxide and zinc oxide in a pre-dispersion chamber first, and the dispersed cerium oxide, lanthanum oxide and zinc oxide enter the coarse grinding chamber through an anti-blocking filter mechanism, and then continue to be transported to the coarse grinding chamber through a spiral conveying blade for further grinding, and then enter the fine grinding chamber through an anti-blocking filter mechanism for final grinding and modification, thereby grinding the material into submicron level and modification, realizing graded grinding of the material, ensuring that the particles are gradually refined to the submicron level, and the specific surface area is greatly increased compared with traditional larger particle size raw materials, and the specific surface area is increased. The close contact interface with the active cerium oxide and lanthanum oxide results in high surface active sites on both surfaces, effectively transferring electrons or ions and enhancing synergistic antibacterial and catalytic properties. Zinc oxide increases the specific surface area, fully releases Zn²⁺, improves antibacterial efficiency, and has a strong interface with the matrix resin. The impact strength of the composite material is improved, the antibacterial property of the pipe is enhanced, and the dispersibility is improved to enhance the overall performance. At the same time, it is carried out simultaneously with grinding and modification. Mechanical force breaks the particles and exposes the highly active surface. The hydrolyzed silane coupling agent is immediately adsorbed and coated, balancing the surface energy of multiple components, inhibiting agglomeration, and improving dispersibility and mechanical strength.

[0011] The present invention controls the cylinder and the rotating shaft to rotate in opposite directions through a dual-mode driving mechanism, thereby enhancing the collision and shearing effect between the grinding medium and the material and avoiding grinding dead angles.

[0012] Preferably, the dual-mode drive mechanism includes a rotating motor, an electric push rod, and a planetary gear mechanism. A limiting groove is provided at one end of the rotating shaft, a sliding groove is provided on the side wall opposite to the limiting groove, a connecting rod is provided in the limiting groove, and limiting blocks that cooperate with the sliding groove are provided on both sides of the connecting rod. The push rod end of the electric push rod is fixedly connected to the connecting rod, the sun gear sleeve of the planetary gear mechanism is fixed on the push rod end of the electric push rod, the inner gear ring of the planetary gear mechanism is fixedly connected to the cylinder, the frame is provided with a slot for facilitating the movement of the sun gear, and the output end of the rotating motor is fixedly connected to the motor end of the electric push rod.

[0013] The planetary gear mechanism includes a sun gear as a power input component; at least three planetary gears evenly distributed around the sun gear and meshing with the outside of the sun gear; a fixed planetary carrier rigidly connected to the external structure, used to fix the axial position of the planetary gears and prevent the planetary gears from revolving; an inner ring gear meshing with the planetary gears, serving as a power output component; wherein, the rotation of the sun gear drives the planetary gears to rotate, and the torque is transmitted through the meshing of the planetary gears and the inner ring gear, so that the inner ring gear outputs a rotational motion opposite to the direction of the sun gear.

[0014] The present invention drives the reciprocation of the sun wheel through the reciprocation of the electric push rod, thereby controlling whether the cylinder rotates, thereby enhancing the grinding effect through the forward and reverse rotation of the cylinder and the rotating shaft, and conveying materials through the spiral blades, so that the materials are gradually reduced.

[0015] Preferably, a mixing mechanism is provided on the portion of the spiral conveying blade located in the fine grinding chamber, the mixing mechanism includes a tube body and an internal mixing unit, the mixing unit is composed of more than three twisted baffles, and the twisted baffle is composed of at least two spiral ribbons wound in opposite directions to form a multi-stage fluid separation channel.

[0016] The present invention adds a hydrolyzed silane coupling agent into the fine grinding chamber, so that cerium oxide, lanthanum oxide and zinc oxide transported from the fine grinding chamber and the hydrolyzed silane coupling agent are stirred by a spiral blade while passing through a mixing mechanism, and the materials are continuously mixed by a twisted baffle, thereby enhancing the wrapping effect, fully wrapping the silane coupling agent and cerium oxide, lanthanum oxide and zinc oxide, reducing the surface energy of the coated particles, preventing agglomeration of submicron particles, ensuring uniform dispersion in the resin, improving processing fluidity, forming a hydrophobic layer to inhibit particle hygroscopicity, and avoiding processing bubbles; and synergistically enhancing the mechanical strength of the pipe.

[0017] Preferably, the anti-clogging filter mechanism includes a first filter, a second filter, and an anti-clogging bouncing ball. The first filter and the second filter are arranged on the side wall of the rotating shaft, and several anti-clogging bouncing balls are arranged between the first filter and the second filter. The anti-clogging bouncing balls are beads with bouncing properties.

[0018] The present invention drives the first filter screen and the second filter screen to rotate by rotating the rotating shaft, thereby driving the anti-clogging bouncing ball to bounce, so that the anti-clogging bouncing ball can hit the filter screen, preventing the filter screen from being blocked by materials, thereby extending the service life of the filter screen.

[0019] Preferably, the tops of the coarse grinding chamber and the fine grinding chamber are both provided with bead replenishing ports, the bottoms of the coarse grinding chamber and the fine grinding chamber are both provided with bead outlets, a grinding bead replenishing mechanism is provided above the bead replenishing ports, and a grinding bead screening mechanism is provided at the bottom of the bead outlets.

[0020] When the grinding beads need to be replaced, the grinding beads are dropped into the grinding bead screening mechanism through the bead outlet. The grinding beads that can be used are screened out by the grinding bead screening mechanism and returned to the grinding bead replenishing mechanism. New grinding beads are replenished into the cavity through the grinding bead replenishing mechanism, thereby timely replacing the worn beads, ensuring that the grinding medium always maintains high activity and appropriate particle size, avoiding insufficient grinding force or contamination of materials due to bead wear, thereby ensuring product particle size uniformity and purity, and improving quality stability.

[0021] The grinding bead replenishing mechanism includes a hopper, a rotating feed tray, a side material guard plate, and a material motor. The hopper is fixed on the frame, the rotating feed tray is arranged at the bottom of the hopper, the roller surface of the rotating feed tray is circumferentially evenly distributed with a number of positioning grooves, the side material guard plate is arranged on the left side of the rotating feed tray, the bottom of the rotating feed tray corresponds to the bead replenishing port, the material motor is fixedly connected to the rotating feed tray, and the side of the side material guard plate close to the rotating feed tray is arc-shaped.

[0022] The invention realizes automatic bead replenishment by causing the grinding beads in the hopper to fall into the positioning groove and the rotating feeding plate to drive the grinding beads to rotate, so that the grinding beads fall into the cylinder in a quantitative manner.

[0023] Preferably, the grinding bead screening mechanism includes a frame, a screen drum, a feeding conveying roller, and a collecting box. The three screen drums are rotatably arranged on the frame. The apertures of the screen holes of the three screen drums increase successively. The feeding conveying roller is arranged on the right side of the frame and at the bottom of the bead outlet. The collecting box is located at the bottom of the screen drum.

[0024] The present invention conveys the beads in the cylinder to the screen cylinder through the feeding conveyor roller, and then passes through the screen cylinders with non-permeable apertures in turn. The grinding beads passing through the screen cylinder with the smallest aperture are the most severely worn and cannot be used any further, so they are removed. The grinding beads passing through the screen cylinder with the second smallest aperture are not severely worn and can be circulated to the fine grinding chamber for continued use. The grinding beads passing through the screen cylinder with the largest aperture can be circulated to the coarse grinding chamber for continued use, thereby removing unwanted grinding beads and allowing grinding beads with less severe wear to be used, ensuring the uniformity and purity of product particle size while saving consumables.

[0025] Preferably, a downwardly inclined buffer plate is provided between the starting end of the frame and two adjacent screen cylinders to prevent the grinding beads that have not passed the previous round of screening from being directly transferred to the next round, thereby ensuring the accuracy of screening.

[0026] Preferably, the segmented cooling step utilizes an intelligent, temperature-controlled, multi-stage spray cooling system with 5-7 cooling zones, each equipped with an independent temperature sensor and electric control valve. This automatically adjusts the water temperature in each zone based on the extrusion speed and temperature of the pipe, achieving gradient cooling and effectively reducing internal stress in the pipe.

[0027] A rare earth antibacterial, impact-resistant and scale-resistant PP-R pipe comprises the following components, calculated by mass: 80-90 parts of PP-R resin; 0.08-0.15 parts of cerium oxide; 0.08-0.15 parts of lanthanum oxide; 0.6-0.9 parts of zinc oxide; 2-4 parts of polyolefin elastomer; 0.2-1.0 parts of maleic anhydride-grafted polypropylene; 0.5-1 parts of organosilicon (molecular weight 600,000-700,000); 0.5-1.2 parts of nano-silicon dioxide; 0.3-0.7 parts of antioxidant; 0.3-0.8 parts of lubricant; and 0.25-0.4 parts of nucleating agent.

[0028] Cerium oxide and lanthanum oxide enhance the charge activity of zinc oxide, promoting zinc ion release and disrupting bacterial structures and enzyme systems, synergistically improving the product's antibacterial properties. Polyolefin elastomer, a toughening modifier, is evenly dispersed in the PP-R resin matrix. Upon impact, the elastomer particles absorb and disperse impact energy, preventing crack formation and propagation. Maleic anhydride-grafted polypropylene acts as a compatibilizer, enhancing the interfacial bonding between the polyolefin elastomer and the PP-R resin, enabling a synergistic effect and strengthening impact resistance. Silicone imparts low surface energy to the PP-R pipe surface, making it difficult for scale to adhere to the pipe wall. Nanosilica, incorporated into the resin matrix, optimizes the material's surface smoothness and reduces pores and rough spots where scale can adhere. A nucleating agent refines the PP-R resin's grain size, resulting in a smoother and denser pipe surface, further reducing the likelihood of scale deposition. This effectively reduces scale accumulation within the pipe, maintains pipeline patency, and improves water delivery efficiency, ultimately achieving the PP-R pipe's antibacterial, impact-resistant, and anti-fouling properties.

[0029] In summary, the beneficial effects of the present invention are: 1. The present invention refines cerium oxide, lanthanum oxide, and zinc oxide to the submicron level through multi-stage grinding. After multi-stage grinding, the cerium oxide and lanthanum oxide are in close contact with each other, resulting in high surface active sites on both surfaces, effective electron or ion transfer, and enhanced synergistic antibacterial and catalytic properties. The zinc oxide after multi-stage grinding has a large specific surface area, fully releases Zn²⁺, and improves antibacterial efficiency. Silane coupling agents are added during the fine grinding process to continuously break up the particles of cerium oxide, lanthanum oxide, and zinc oxide. Newly generated surface active sites can be promptly combined with the silane coupling agent for thorough mixing and coating. Because the submicron particles coated with the silane coupling agent have a large specific surface area and excellent interfacial compatibility, the particles are uniformly dispersed to form a physically embedded "microskeleton". The organic end of the silane is entangled with the resin, and the inorganic end is bonded to the particles, forming a strong interface layer, effectively transferring loads, reducing stress concentration, and significantly improving the tensile strength and impact resistance of the PP-R pipe. During the preparation of the masterbatch, twin-screw extrusion granulation ensures that the nano-silica is well dispersed in the resin, providing a guarantee for the anti-fouling properties of the pipe. During the raw material blending stage, multiple components are compounded to form a toughening system, enhancing the pipe's impact resistance. The additives also synergistically optimize overall performance. During the extrusion process, a twin-screw extruder, coupled with vacuum sizing and staged cooling, improves pipe quality, enabling continuous automated production, increasing yield rates, and reducing costs. This process, through the synergistic integration of various steps, enhances the antibacterial, impact, and anti-fouling properties of PP-R pipes, while also optimizing the production process, demonstrating its practical value. 2. The present invention uses a spiral conveying blade to disperse cerium oxide, lanthanum oxide and zinc oxide in the pre-dispersion chamber first, and the dispersed cerium oxide, lanthanum oxide and zinc oxide enter the coarse grinding chamber through the anti-blocking filter mechanism, and then continue to be transported to the coarse grinding chamber through the spiral conveying blade for further grinding, and then enter the fine grinding chamber through the anti-blocking filter mechanism for the final grinding and modification, thereby grinding the material into submicron level and modification, realizing graded grinding of the material, ensuring that the particles are gradually refined to the submicron level, and its specific surface area is greatly increased compared with traditional larger particle size raw materials, increasing the specific surface area. The close contact interface between cerium oxide and lanthanum oxide results in high surface active sites on both surfaces, effectively transferring electrons or ions and enhancing synergistic antibacterial and catalytic properties. Zinc oxide increases the specific surface area, fully releasing Zn²⁺, improving antibacterial efficiency, and strengthening the interface with the matrix resin. The composite material has increased impact strength, enhanced antibacterial properties of the pipe, and improved dispersibility to enhance comprehensive performance. Simultaneously with grinding and modification, mechanical force breaks up the particles and exposes highly active surfaces. The hydrolyzed silane coupling agent is immediately adsorbed and coated, balancing the surface energy of multiple components, inhibiting agglomeration, and improving dispersibility and mechanical strength. 3. The present invention adds a hydrolyzed silane coupling agent to the fine grinding chamber, so that the cerium oxide, lanthanum oxide, and zinc oxide transported from the fine grinding chamber and the hydrolyzed silane coupling agent are stirred by the spiral blades while passing through the mixing mechanism and the twisted baffles to continuously mix the materials, thereby enhancing the coating effect. The silane coupling agent and the cerium oxide, lanthanum oxide, and zinc oxide are fully coated. After the coated particles are coated, the surface energy is reduced, the agglomeration of submicron particles is prevented, and uniform dispersion in the resin is ensured. The processing fluidity is improved, and a hydrophobic layer is formed to inhibit the hygroscopicity of the particles and avoid processing bubbles. The mechanical strength of the pipe is synergistically enhanced. 4. When the grinding beads need to be replaced, the grinding beads fall into the grinding bead screening mechanism through the bead outlet. The grinding beads that can be used are screened out by the grinding bead screening mechanism and returned to the grinding bead replenishing mechanism. New grinding beads are replenished into the cavity through the grinding bead replenishing mechanism, thereby timely replacing the worn beads, ensuring that the grinding medium always maintains high activity and appropriate particle size, avoiding insufficient grinding force or contamination of materials due to bead wear, thereby ensuring product particle size uniformity and purity, and improving quality stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is an overall schematic diagram of the multi-stage modified grinding device of the present invention; Figure 2 It is a schematic cross-sectional view of the cylinder of the present invention; Figure 3 This invention Figure 2 An enlarged schematic diagram of point A; Figure 4 is a cross-sectional schematic diagram of the connection between the rotating shaft and the connecting rod of the present invention; Figure 5 It is a cross-sectional schematic diagram of the anti-blocking filter mechanism of the present invention; Figure 6 is a schematic diagram of the grinding bead replenishing mechanism of the present invention; Figure 7 is a schematic diagram of the grinding bead screening mechanism of the present invention; Figure 8 It is a schematic diagram of the screen drum of the present invention; Figure 9 is a schematic cross-sectional view of the screen drum of the present invention; Figure 10 is a schematic cross-sectional view of the mixing mechanism of the present invention; Figure 11 Schematic diagram of the twisted baffle of the present invention; 1. Multi-stage modified grinding device; 10. Frame; 11. Cylinder; 12. Rotating shaft; 13. Spiral conveying blade; 14. Anti-blocking filter mechanism; 15. Dual-mode drive mechanism; 19. Grinding beads; 16. Pre-dispersion chamber; 17. Coarse grinding chamber; 18. Fine grinding chamber; 151. Rotating motor; 152. Electric push rod; 153. Planetary gear mechanism; 121. Limiting groove; 122. Slideway; 157. Connecting rod; 158. Limiting block; 110. Slot; 141. First filter; 142. Second filter 143. Anti-clogging bouncing ball; 111. Bead replenishing port; 112. Bead outlet; 2. Grinding bead replenishing mechanism; 3. Grinding bead screening mechanism; 21. Hopper; 22. Rotating feed tray; 23. Side material guard plate; 24. Material motor; 221. Positioning groove; 31. Frame; 32. Screen drum; 33. Feeding conveyor roller; 34. Collecting box; 310. Buffer plate; 41. Mixing mechanism; 411. Tube body; 412. Mixing unit; 413. Twisted baffle; 414. Two-strand spiral belt; 415. Multi-stage fluid separation channel. DETAILED DESCRIPTION

[0031] The following specific embodiments are merely explanations of the present invention and are not limitations of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the embodiments as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

[0032] The present invention will be described in detail below with reference to the accompanying drawings using embodiments.

[0033] Example 1

[0034] A method for producing rare earth antibacterial, anti-impact and anti-scale PP-R pipes, comprising the following steps: S1. Grinding and Modification: Cerium oxide, lanthanum oxide, and zinc oxide are refined to submicron size using a multi-stage modified grinding apparatus 1. A portion of the hydrolyzed silane coupling agent is then added to the fine grinding chamber 18 of the multi-stage modified grinding apparatus 1 for initial coating. The remaining hydrolyzed silane coupling agent is then added for full coating. The particles are then dried to form modified composite particles. The initial small addition reduces self-condensation, preferentially anchors the particles to the particle surface, and improves dispersibility. A secondary coating enhances coating uniformity, forms a dense protective layer, and optimizes interfacial bonding. Avoid agglomeration, improve grinding efficiency and final material properties. These modified composite particles can be better compatible with the resin matrix when subsequently mixed with PP-R resin, which is equivalent to increasing the binding force between the particles and the resin, making the masterbatch more stable in the system and less likely to precipitate.

[0035] S2. Masterbatch preparation: Nano-silica is mixed with PP-R resin and granulated by twin-screw extrusion; S3 raw material blending: PP-R resin, step S1 treatment of the modified composite particles, polyolefin elastomer, maleic anhydride grafted polypropylene, silicone, nano-silica masterbatch and auxiliary additives premix mixing; S4. Extrusion molding: The blended material is extruded into a pipe blank through a twin-screw extruder, and then subjected to vacuum sizing, segmented cooling, and traction cutting to obtain the finished pipe.

[0036] The twin-screw extruder's screw elements are composed of a conveying section, a shear mixing section, a compression section, and a homogenizing section. The shear block density is medium (6 to 8 groups per screw). The conveying section can stably convey resin and filler; the shear mixing section can generate strong shear through forward / reverse screw elements to disperse submicron rare earth and zinc oxide; the homogenizing section ensures uniform melt density, reduces extrusion pressure fluctuations, and thus improves filler dispersion uniformity.

[0037] After the tube blank is extruded from the die head, it immediately enters the vacuum sizing sleeve. The vacuum degree is controlled at 0.068MPa and the temperature of the sizing sleeve is maintained at 25℃ to ensure the outer diameter accuracy of the tube.

[0038] Use a traction machine to pull the cooled pipe forward at a steady speed (adjusted according to the extrusion speed, generally 0.5-1.5m / min). The traction force of the traction machine should be moderate to prevent the pipe from deformation or stretching.

[0039] Post-processing: Place the cut pipe in an environment with a temperature of 22°C and a humidity of 55 parts for 24 hours to eliminate residual stress.

[0040] like Figure 1-Figure 4As shown, the multi-stage modified grinding device 1 includes a frame 10, a barrel 11, a rotating shaft 12, a spiral conveying blade 13, an anti-blocking filter mechanism 14, a dual-mode drive mechanism 15, and grinding beads 19. The rotating shaft 12 is arranged in the barrel 11 through a bearing, and the outer ring of the barrel 11 is arranged on the frame 10 through a bearing. The spiral conveying blade 13 is arranged on the rotating shaft 12, and two anti-blocking filter mechanisms 14 are sequentially sleeved on the side walls of the rotating shaft 12 to divide the cavity of the barrel 11 into a pre-dispersion chamber 16, a coarse grinding chamber 17 and a fine grinding chamber 18. The anti-blocking filter mechanism 15 is provided with a plurality of screws, and the screws are provided with a plurality of screws. The holes of the filter mechanism 14 are successively reduced. The grinding beads 19 are provided in the coarse grinding chamber 17 and the fine grinding chamber 18. The dual-mode drive mechanism 15 controls the cylinder 11 and the rotating shaft 12 to rotate forward and reverse or the rotating shaft 12 to rotate alone. The dual-mode drive mechanism 15 includes a rotating motor 151, an electric push rod 152, and a planetary gear mechanism 153. A limiting groove 121 is provided at one end of the rotating shaft 12. A sliding groove 122 is provided on the side wall opposite to the limiting groove 121. A connecting rod 157 is provided in the limiting groove 121. Both sides of the connecting rod 157 are provided with a connecting rod 157. The limit blocks 158 of the slide groove 122 cooperate with each other, the push rod end of the electric push rod 152 is fixedly connected to the connecting rod 157, the sun gear sleeve of the planetary gear mechanism 153 is fixed on the push rod end of the electric push rod 152, the inner gear ring of the planetary gear mechanism 153 is fixedly connected to the cylinder 11, and the frame 10 is provided with a slot 110 for facilitating the movement of the sun gear. The output end of the rotating motor 151 is fixedly connected to the motor end of the electric push rod 152, and the tops of the coarse grinding chamber 17 and the fine grinding chamber 18 are both provided with a bead filling port 111. 8 is provided with a bead outlet 112 at the bottom, a grinding bead replenishing mechanism 2 is provided above the bead replenishing mechanism 111, a grinding bead screening mechanism 3 is provided at the bottom of the bead outlet 112, the cylinder 11 and the bead replenishing mechanism 111 are provided with cerium oxide, lanthanum oxide and zinc oxide feed ports 100, a preliminary feed port 101 and a secondary feed port 102 for silane coupling agent at the same top, and a discharge port 103 is provided at the bottom. These ports are all provided with valve mechanisms to control the closing and opening of the ports. When the cylinder rotates, each port is closed, and when feeding, each port is opened. This valve is a prior art and will not be described in detail in this case.

[0041] like Figure 10-11 As shown, a mixing mechanism 41 is provided on the portion of the spiral conveying blade 13 located in the fine grinding chamber 18. The mixing mechanism 41 includes a tube body 411 and an internal mixing unit 412. The mixing unit 412 is composed of three or more twisted baffles 413. The twisted baffles 413 are composed of at least two spiral ribbons 414 wound in opposite directions to form a multi-stage fluid separation channel 415.

[0042] like Figure 5As shown, the anti-clogging filter mechanism 14 includes a first filter 141, a second filter 142, and an anti-clogging bouncing ball 143. The first filter 141 and the second filter 142 are arranged on the side wall of the rotating shaft 12, and several anti-clogging bouncing balls 143 are arranged between the first filter 141 and the second filter 142.

[0043] like Figure 6 As shown, the grinding bead replenishing mechanism 2 includes a hopper 21, a rotating feed tray 22, a side guard plate 23, and a material motor 24. The hopper 21 is fixed on the frame 10, and the rotating feed tray 22 is arranged at the bottom of the hopper 21. The roller surface of the rotating feed tray 22 is circumferentially evenly distributed with a number of positioning grooves 221. The side guard plate 23 is arranged on the left side of the rotating feed tray 22. The bottom of the rotating feed tray 22 corresponds to the bead replenishing port 111. The material motor 24 is fixedly connected to the rotating feed tray 22. The side guard plate 23 close to the rotating feed tray 22 is arc-shaped.

[0044] like Figure 7-9 As shown, the grinding bead screening mechanism 3 includes a frame 31, a screen drum 32, a feeding conveying roller 33, and a collecting box 34. The three screen drums 32 are rotatably arranged on the frame 31. The apertures of the sieve holes of the three screen drums 32 increase in sequence. The feeding conveying roller 33 is arranged on the right side of the frame 31 and is located at the bottom of the bead outlet 112. The collecting box 34 is located at the bottom of the screen drum 32. A downwardly inclined buffer plate 310 is provided between the starting end of the frame 31 and the two adjacent screen drums 32. The screen drum 32 includes a ring An annular filter screen 321, a cover 322, and a rotating rod 323 are provided. The cover 322 is provided on both sides of the annular filter screen 321. The rotating rod 323 is fixed on the cover 322. The rotating rod and the frame 31 are rotatably connected through bearings. A boss 324 is formed on the inner side of the cover 322. The diameter of the boss 324 is smaller than the diameter of the cover. The annular filter screen 321 is tightly fitted with the boss and is detachably connected with screws, so that the screen is replaceable. Different screens can be replaced according to different grinding beads.

[0045] The segmented cooling process utilizes an intelligent, temperature-controlled, multi-stage spray cooling system with 5-7 cooling zones, each equipped with an independent temperature sensor and electric control valve. Based on the pipe extrusion speed and temperature, the water temperature is automatically adjusted to each zone, such as 30°C in the first zone, 25°C in the second zone, and then gradually decreasing to 15°C in the final zone, achieving gradient cooling and effectively reducing internal stress in the pipe.

[0046] A rare earth antibacterial, impact-resistant and scale-resistant PP-R pipe comprises the following components, calculated by mass: 85 parts of PP-R resin; 1 part of cerium oxide; 1 part of lanthanum oxide; 0.8 part of zinc oxide; 3 parts of polyolefin elastomer; 0.8 part of maleic anhydride-grafted polypropylene; 0.8 part of organosilicon (molecular weight 600,000-700,000); 0.8 part of nano-silica; 0.5 part of antioxidant; 0.6 part of lubricant; and 0.3 part of nucleating agent.

[0047] Working principle: When in use, in the initial state, the bead filling port 111 of the cylinder, the cerium oxide, lanthanum oxide and zinc oxide feeding port 100, the silane coupling agent preliminary feeding port 101 and the secondary feeding port 102 are upward, the discharge port 103 and the bead outlet 112 are downward, and the cerium oxide, lanthanum oxide and zinc oxide powders are placed in the pre-dispersion chamber 16. The electric push rod 152 drives the sun gear away from the planetary gear, so that the rotating shaft rotates, and the cylinder does not rotate. Then the motor is rotated to drive the rotating shaft 12 to rotate. The spiral blades disperse the cerium oxide, lanthanum oxide and zinc oxide powders while moving them to the coarse grinding chamber 17 to avoid agglomeration. The preliminarily dispersed powders are prevented from agglomerating by the anti-blocking filter mechanism 14. The cerium oxide, lanthanum oxide and zinc oxide powders enter the coarse grinding chamber 17, and then the rotary motor 151 rotates, thereby driving the rotation shaft 12 to rotate. At the same time, the rotation of the sun gear drives the rotation of the inner ring gear, thereby driving the cylinder 11 to rotate in the opposite direction of the rotation shaft 12, so that the cerium oxide powder is initially ground in the coarse grinding chamber 17. The electric push rod 152 drives the sun gear away from the planetary gear, and then the rotating motor drives the rotation shaft 12 to rotate. The spiral blade pushes the coarsely ground cerium oxide, lanthanum oxide and zinc oxide to move to the fine grinding chamber 18, and the coarsely ground cerium oxide, lanthanum oxide and zinc oxide pass through the anti-blocking filter mechanism 14 and enter the fine grinding chamber 18; At this time, part of the hydrolyzed silane coupling agent is added into the fine grinding chamber 18, and then the electric push rod 152 drives the sun gear of the planetary gear mechanism 153 so that the sun gear is meshed with the planetary gear, so that the rotating shaft rotates and the cylinder rotates in the opposite direction, cooperating with the grinding beads and the mixing mechanism 41 to grind and modify. After the cylinder rotates several times, the initial feed port 101 and the secondary feed port 102 of the silane coupling agent are upward, and the rotation is stopped. The remaining hydrolyzed silane coupling agent is added and rotated again to fully wrap it. The rotation is then stopped and the cylinder returns to its original position (the bead filling port 111 of the cylinder, the cerium oxide, lanthanum oxide and zinc oxide feed port 100, the initial feed port 101 and the secondary feed port 102 of the silane coupling agent are upward, and the discharge port 103 and the bead discharge port 112 are downward). Then the electric push rod 152 drives the sun gear away from the planetary gear, so that the rotating shaft rotates, and the cylinder does not rotate. The rotating motor drives the rotating shaft 12 to rotate, and the spiral blades push the finely ground and modified composite material to be discharged, thereby grinding the material into the submicron level, realizing graded grinding of the material, and ensuring that the particles are gradually refined to the submicron level. Compared with traditional larger particle size raw materials, its specific surface area is greatly increased, increasing the specific surface area and activity. The close contact interface between cerium oxide and lanthanum oxide leads to high surface active sites of both surfaces, effectively transferring electrons or ions, and enhancing synergistic antibacterial and catalytic properties. Zinc oxide increases the specific surface area, fully releases Zn²⁺, improves antibacterial efficiency, and has a strong interface with the matrix resin. The impact strength of the composite material is improved, the antibacterial property of the pipe is enhanced, and the dispersibility is improved to enhance the overall performance. At the same time, it is carried out simultaneously with grinding and modification. Mechanical force breaks the particles and exposes the highly active surface. The hydrolyzed silane coupling agent is immediately adsorbed and coated, balancing the surface energy of the multiple components, inhibiting agglomeration, and improving the dispersibility and mechanical strength.

[0048] Example 2

[0049] Different from Example 1, A rare earth antibacterial, impact-resistant and scale-resistant PP-R pipe comprises the following components, calculated by mass: 80 parts of PP-R resin; 0.08 parts of cerium oxide; 0.08 parts of lanthanum oxide; 0.6 parts of zinc oxide; 2 parts of polyolefin elastomer; 0.2 parts of maleic anhydride-grafted polypropylene; 0.5 parts of organosilicon (molecular weight 600,000-700,000); 0.5 parts of nano-silica; 0.3 parts of antioxidant; 0.3 parts of lubricant; and 0.25 parts of nucleating agent.

[0050] Example 3

[0051] Different from Example 1, A rare earth antibacterial, impact-resistant and scale-resistant PP-R pipe comprises the following components, calculated by mass: 90 parts of PP-R resin; 0.15 parts of cerium oxide; 0.15 parts of lanthanum oxide; 0.9 parts of zinc oxide; 4 parts of polyolefin elastomer; 1.0 parts of maleic anhydride-grafted polypropylene; 1 part of organosilicon (molecular weight 600,000-700,000); 1.2 parts of nano-silicon dioxide; 0.7 parts of antioxidant; 0.8 parts of lubricant; and 0.4 parts of nucleating agent.

[0052] The tubes produced in Example 1, Example 2 and Example 3 were subjected to the following tests: Antibacterial performance test: Referring to GB / T 31402-2015 "Test method for antibacterial performance of plastic surfaces", the pipe was cut into 5cm×5cm samples, inoculated with Escherichia coli and Staphylococcus aureus liquid, and cultured in a constant temperature incubator at 37℃ for 24 hours. The number of colonies was determined by the viable bacteria count method, and the calculated antibacterial rate reached 99.2%.

[0053] Impact resistance test: According to GB / T 18742.2-2017 "Polypropylene Piping Systems for Hot and Cold Water Part 2: Pipes", the pipes were subjected to a simply supported beam notched impact test at -20°C. The specimen size was 80mm×10mm×4mm, the notch depth was 2mm, and the impact strength was 28kJ / m². Anti-scale performance test: To simulate a scale deposition environment, the pipe sample was placed in a solution containing 10mmol / L CaCl2 and 5mmol / L Na2CO3 and immersed at 60°C for 72 hours. The amount of scale adhesion was calculated by weighing method, and the water contact angle was converted to 110°. The scale adhesion amount was reduced by 82% compared with ordinary PP-R pipes.

[0054]

[0055] As can be seen from the data in the above table, the formula within the scope of the claims of the present invention, through the synergistic effect of various components, has achieved comprehensive improvements in the antibacterial, impact resistance, and anti-fouling properties of PP-R pipes, effectively solving the performance shortcomings of traditional pipes and verifying the practical value of this formula.

Claims

1. A method for producing rare earth antibacterial, anti-impact and anti-scale PP-R pipes, characterized in that: The following steps are involved: S1. Grinding modification treatment: cerium oxide, lanthanum oxide and zinc oxide are refined to submicron level by a multi-stage modified grinding device (1), a portion of the hydrolyzed silane coupling agent is first added to the fine grinding chamber (18) of the multi-stage modified grinding device (1) for initial coating, and then the remaining hydrolyzed silane coupling agent is added for full coating, and then dried to form modified composite particles; S2. Masterbatch preparation: Nano-silica is mixed with PP-R resin and granulated by twin-screw extrusion; S3 raw material blending: PP-R resin, step S1 treatment of the modified composite particles, polyolefin elastomer, maleic anhydride grafted polypropylene, silicone, nano-silica masterbatch and auxiliary additives premix mixing; S4. Extrusion molding: The blended material is extruded into a pipe blank through a twin-screw extruder, and then subjected to vacuum sizing, segmented cooling, and traction cutting to obtain the finished pipe.

2. The method for producing a rare earth antibacterial, anti-impact and anti-scale PP-R pipe according to claim 1, characterized in that: The multi-stage modified grinding device (1) comprises a frame (10), a barrel (11) arranged on the frame (10), a rotating shaft (12), a spiral conveying blade (13), an anti-blocking filter mechanism (14), a dual-mode driving mechanism (15), and grinding beads (19), wherein the rotating shaft (12) is arranged in the barrel (11) through a bearing, the outer ring of the barrel (11) is arranged on the frame (10) through a bearing, the spiral conveying blade (13) is arranged on the rotating shaft (12), and the two The anti-blocking filter mechanisms (14) are sequentially sleeved on the side walls of the rotating shaft (12) to divide the cavity of the cylinder (11) into a pre-dispersion cavity (16), a coarse grinding cavity (17), and a fine grinding cavity (18). The holes of the anti-blocking filter mechanisms (14) are successively reduced in size. The coarse grinding cavity (17) and the fine grinding cavity (18) are both provided with the grinding beads (19). The dual-mode driving mechanism (15) controls the cylinder (11) and the rotating shaft (12) to rotate forward and reverse or the rotating shaft (12) to rotate alone.

3. The method for producing a rare earth antibacterial, anti-impact and anti-scale PP-R pipe according to claim 2, characterized in that: The dual-mode drive mechanism (15) includes a rotating motor (151), an electric push rod (152), and a planetary gear mechanism (153). A limiting groove (121) is provided at one end of the rotating shaft (12). A sliding groove (122) is provided on the side wall opposite to the limiting groove (121). A connecting rod (157) is provided in the limiting groove (121). Limiting blocks (158) that cooperate with the sliding groove (122) are provided on both sides of the connecting rod (157). ), the push rod end of the electric push rod (152) is fixedly connected to the connecting rod (157), the sun gear of the planetary gear mechanism (153) is sleeved and fixed on the push rod end of the electric push rod (152), the inner gear ring of the planetary gear mechanism (153) is fixedly connected to the cylinder (11), the frame (10) is provided with a slot (110) for facilitating the movement of the sun gear, and the output end of the rotating motor (151) is fixedly connected to the motor end of the electric push rod (152).

4. The method for producing a rare earth antibacterial, anti-impact and anti-scale PP-R pipe according to claim 2, characterized in that: A mixing mechanism (41) is provided on the portion of the spiral conveying blade (13) located in the fine grinding chamber (18). The mixing mechanism (41) comprises a tube body (411) and an internal mixing unit (412). The mixing unit (412) is composed of three or more twisted baffles (413). The twisted baffles (413) are formed by at least two spiral ribbons (414) wound in opposite directions to form a multi-stage fluid separation channel (415).

5. The method for producing a rare earth antibacterial, anti-impact and anti-scale PP-R pipe according to claim 2, characterized in that: The anti-clogging filter mechanism (14) comprises a first filter (141), a second filter (142), and an anti-clogging bouncing ball (143). The first filter (141) and the second filter (142) are arranged on the side wall of the rotating shaft (12), and a plurality of the anti-clogging bouncing balls (143) are arranged between the first filter (141) and the second filter (142).

6. The method for producing a rare earth antibacterial, anti-impact and anti-scale PP-R pipe according to claim 2, characterized in that: The tops of the coarse grinding chamber (17) and the fine grinding chamber (18) are both provided with bead replenishing openings (111), and the bottoms of the coarse grinding chamber (17) and the fine grinding chamber (18) are both provided with bead outlets (112). A grinding bead replenishing mechanism (2) is provided above the bead replenishing openings (111), and a grinding bead screening mechanism (3) is provided at the bottom of the bead outlets (112).

7. The method for producing a rare earth antibacterial, anti-impact and anti-scale PP-R pipe according to claim 6, characterized in that: The grinding bead replenishing mechanism (2) includes a hopper (21), a rotating feeding plate (22), a side material guard plate (23), and a material motor (24). The hopper (21) is fixed on the frame (10). The rotating feeding plate (22) is arranged at the bottom of the hopper (21). The roller surface of the rotating feeding plate (22) is uniformly distributed with a plurality of positioning grooves (221) on the circumference. The side material guard plate (23) is arranged on the left side of the rotating feeding plate (22). The bottom of the rotating feeding plate (22) corresponds to the bead replenishing port (111). The material motor (24) is fixedly connected to the rotating feeding plate (22).

8. The method for producing a rare earth antibacterial, anti-impact and anti-scale PP-R pipe according to claim 6, characterized in that: The grinding bead screening mechanism (3) includes a frame (31), a screen drum (32), a feeding conveying roller (33), and a collecting box (34). The three screen drums (32) are rotatably arranged on the frame (31). The apertures of the screen holes of the three screen drums (32) increase in sequence. The feeding conveying roller (33) is arranged on the right side of the frame (31) and is located at the bottom of the bead outlet (112). The collecting box (34) is located at the bottom of the screen drum (32).

9. The method for producing a rare earth antibacterial, anti-impact and anti-scale PP-R pipe according to claim 8, characterized in that: A downwardly inclined buffer plate (310) is provided between the starting end of the frame (31) and two adjacent screen drums (32).

10. A rare earth antibacterial, anti-impact and anti-scale PP-R pipe, characterized in that: The invention comprises the following components in parts by mass: 80 parts to 90 parts of PP-R resin; 0.08 parts to 0.15 parts of cerium oxide; 0.08 parts to 0.15 parts of lanthanum oxide; Zinc oxide 0.6-0.9 parts; polyolefin elastomer 2-4 parts; Maleic anhydride grafted polypropylene 0.2-1.0 parts; organosilicon 0.5-1 parts; nano-silicon dioxide 0.5-1.2 parts; antioxidant 0.3-0.7 parts; lubricant 0.3-0.8 parts; Nucleating agent 0.25 parts - 0.4 parts.

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