Lightweight high-toughness mpp composite cable protection pipe

Abstract

This invention relates to the field of cable protection conduit technology, specifically a lightweight, high-toughness MPP composite cable protection conduit. In this invention, the outer layer is formed of a first composite material, providing weather resistance and mechanical protection; the inner layer is formed of a third composite material, providing insulation and a low-friction interface; and the middle layer is formed of a second composite material, serving as the main structural layer and simultaneously undertaking the dual functions of lightweighting and toughening. Hollow glass microspheres and basic magnesium sulfate whiskers are introduced into the middle layer, reducing the conduit's weight while compensating for the rigidity loss due to density reduction through the fiber reinforcement effect of the whiskers. Polyolefin elastomers and SEBS-g-MAH synergistically exert elastomer toughening and interface compatibilization effects, while nano-calcium carbonate provides nano-filling and rigid particle toughening effects. A β-crystal nucleating agent further enhances toughness by regulating the polypropylene crystal structure. These multiple toughening mechanisms form a multi-scale synergistic toughening network within the middle layer.

Description

Technical Field

[0001] This invention relates to the field of cable protection pipe technology, specifically a lightweight, high-toughness MPP composite cable protection pipe. Background Technology

[0002] MPP composite cable protection pipes are pipes made from modified polypropylene resin through extrusion processing. They have excellent insulation properties, heat resistance, and mechanical strength, and are widely used for the underground laying protection of power cables and communication cables. With the advancement of urban power grid undergrounding and infrastructure construction, cable protection pipes often need to be laid in environments with high traffic loads and complex geological conditions, which puts forward higher requirements for the lightweight and impact toughness of the pipes. Through formula modification and multi-layer composite structure design, the self-weight can be reduced and the toughness can be improved while ensuring the mechanical protection function of the pipe. This is an important research direction in the field of MPP cable protection pipes.

[0003] To achieve lightweighting, existing MPP cable protection pipes typically reduce their weight by adding low-density inorganic fillers. However, the introduction of large amounts of low-density fillers disrupts the continuity of the matrix, significantly reducing the pipe's toughness and impact resistance, making it prone to cracking during handling, construction, and service. While simply increasing the amount of elastomer can improve toughness, it results in insufficient rigidity, making it difficult to meet the load-bearing requirements of buried installations. The main challenge facing existing technologies is how to achieve lightweighting while maintaining high toughness and good overall mechanical properties. Therefore, this invention provides a lightweight, high-toughness MPP composite cable protection pipe. Summary of the Invention

[0004] The purpose of this invention is to provide a lightweight and high-toughness MPP composite cable protection pipe. The lightweight and high-toughness MPP composite cable protection pipe prepared by this invention achieves lightweighting while exhibiting excellent comprehensive impact resistance, effectively balancing lightweighting and high toughness.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A lightweight, high-toughness MPP composite cable protection pipe is composed of a first composite material, a second composite material, and a third composite material. The first composite material comprises the following raw materials in parts by weight: 80-85 parts polypropylene resin, 6-8 parts filler, 2-2.5 parts polyolefin elastomer, 1.5-2 parts orange-red masterbatch, 1-1.5 parts antioxidant and 0.8-1 parts light stabilizer; The second composite material comprises the following raw materials in parts by weight: 70-75 parts polypropylene resin, 6-8 parts polyolefin elastomer, 3-4 parts SEBS-g-MAH, 8-12 parts basic magnesium sulfate whiskers, 6-8 parts hollow glass microspheres, 5-6 parts nano calcium carbonate, 0.06-0.08 parts β-crystal nucleating agent, 2.5-3 parts maleic anhydride grafted polypropylene, and 0.8-1 parts antioxidant; The third composite material comprises the following raw materials in parts by weight: 85-90 parts polypropylene resin, 2-3 parts polyolefin elastomer, 0.5-0.8 parts antioxidant, and 0.3-0.4 parts rutile titanium dioxide; The polypropylene resin used is impact-resistant copolymer polypropylene.

[0006] Preferably, the pipe includes an outer layer, a middle layer and an inner layer arranged sequentially from the outside to the inside along the radial direction of the pipe. The outer layer is formed of a first composite material, the middle layer is formed of a second composite material, and the inner layer is formed of a third composite material. The outer layer, the middle layer and the inner layer are compositely connected in the molten state by a three-layer co-extrusion method. Based on the total thickness of the pipe wall, the outer layer accounts for 15-20% of the thickness, the inner layer accounts for 10-15% of the thickness, and the middle layer is the remaining thickness.

[0007] Preferably, the filler is prepared by the following method: hollow fine aluminosilicate microspheres are vacuum dried at 80-90℃ for 2-4 hours; KH550 is added to a mixture of ethanol and water to obtain a first silane treatment solution; the dried hollow fine aluminosilicate microspheres are added to a low-shear mixing device; the first silane treatment solution is atomized and sprayed into the dried hollow fine aluminosilicate microspheres at 50-65℃ and 40-80 rpm; after spraying, mixing continues for 10-20 minutes; the resulting product is vacuum dried at 80-90℃ for 2-3 hours to obtain a first premix; needle-shaped wollastonite, flake-shaped monohydrate alumina, and granular material are dried and mixed to obtain a second premix; KH560 is added to a mixture of ethanol and water to obtain a second silane treatment solution; and so on. Under the conditions of a second premix temperature of 60-75℃ and a stirring speed of 100-180rpm, the second silane treatment liquid is atomized and sprayed into the second premix, and mixing is continued for 15-25min. The resulting product is vacuum dried at 90-105℃ for 2-4h to obtain the third premix. The first premix is ​​added to a 25% ethanol aqueous solution, and the solid content is controlled at 15-25%. Under the shear conditions of 60-75℃ and 60-100r / min, the third premix is ​​added in 3-5 portions, and stirring is continued for 10-20min after each addition. After all the premix is ​​added, the temperature is raised to 75-85℃ and the reaction is carried out for 1-2h. The resulting product is filtered and vacuum dried at 80-95℃, and then kept at 110-125℃ for 1-2h to obtain the filler.

[0008] Preferably, the granules are prepared by the following method: cerium oxide is added to a mixture of ethanol and water, mixed well, and then a nonionic dispersant is added. The mixture is further mixed to obtain a dispersion, which is then set aside. Tetraethyl orthosilicate is mixed with ethanol to obtain a mixture, which is then set aside. The pH of the dispersion is adjusted to 8.5-9.5. The mixture is added dropwise at 25-40°C with continuous stirring. After the addition is complete, the reaction continues for 2-4 hours. The solid is obtained by centrifugation, washed with ethanol and deionized water respectively, and then vacuum dried at 80-100°C for 6-10 hours. After that, it is heat-treated at 350-450°C for 1-2 hours to obtain the granules.

[0009] Preferably, the volume ratio of KH550, ethanol and water in the first silane treatment solution is 1:35-45:8-12, the volume ratio of KH560, ethanol and water in the second silane treatment solution is 1:40-50:10-15, the mass ratio of acicular wollastonite, flaky monohydrate alumina and granular material is 23-28:11-15:4-6, and the mass ratio of the first premix and the third premix is ​​60:40-48.

[0010] Preferably, the mass ratio of cerium oxide, ethanol, water and nonionic dispersant is 1:3.5-4.5:1.3-1.5:0.2-0.4, the mass ratio of cerium oxide to tetraethyl orthosilicate is 1:0.6-0.8, and the mass ratio of tetraethyl orthosilicate to ethanol is 1:3-5.

[0011] Preferably, the maleic anhydride grafting rate of SEBS-g-MAH is 0.6-1.5%, the styrene content is 25-35% by mass, and the maleic anhydride grafting rate of maleic anhydride-grafted polypropylene is 0.8-1.5%.

[0012] Preferably, the light stabilizer is composed of a hindered amine light stabilizer and a benzotriazole UV absorber in a mass ratio of 2:1.

[0013] Preferably, the antioxidant is composed of hindered phenolic antioxidant and phosphite antioxidant in a mass ratio of 1:1.5-2.5.

[0014] A preferred method for preparing lightweight, high-toughness MPP composite cable protection pipe includes the following steps: First composite material, second composite material, and third composite material are melted and granulated separately, then added to an outer layer extruder, an intermediate layer extruder, and an inner layer extruder, respectively. The temperature of the outer layer material is 180-200℃, the temperature of the intermediate layer material is 185-205℃, the temperature of the inner layer material is 180-200℃, and the temperature of the co-extrusion die head is 190-205℃. After the three melts converge in the co-extrusion die head, they are extruded through an annular die and sequentially pass through an air precooling section, a first vacuum sizing and cooling section, and a second cooling section. The length of the air precooling section is 30-100mm. The cooling water temperature of the first vacuum sizing and cooling section is 35-50℃, and the cooling water temperature of the second cooling section is 18-30℃. After traction, cutting, and end-face processing, lightweight, high-toughness MPP composite cable protection pipe is obtained.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention adopts a three-layer functional gradient structure design. The outer layer is formed by a first composite material, providing weather resistance and mechanical protection. The inner layer is formed by a third composite material, providing insulation and a low-friction interface. The middle layer is formed by a second composite material, serving as the main structural layer and simultaneously undertaking the dual functions of lightweighting and toughening. Hollow glass microspheres and basic magnesium sulfate whiskers are introduced into the middle layer. While reducing the self-weight of the pipe, the fiber reinforcement effect of the whiskers compensates for the rigidity loss caused by the reduction in density. Polyolefin elastomer and SEBS-g-MAH synergistically play the roles of elastomer toughening and interface compatibilization. Nano-calcium carbonate plays the role of nanofilling and rigid particle toughening. β-crystal nucleating agent further improves toughness by regulating the polypropylene crystal structure. Multiple toughening mechanisms form a multi-scale synergistic toughening network in the middle layer, effectively compensating for the influence of low-density fillers on the continuity of the matrix. Thus, while achieving lightweight pipe, high toughness and good comprehensive mechanical properties are ensured, solving the problem of difficulty in achieving both lightweighting and high toughness in the prior art.

[0016] 2. In this invention, the filler is prepared through multi-stage surface treatment. Hollow fine aluminosilicate microspheres are treated with KH550 to form a first premix. Needle-shaped wollastonite and flaky monohydrated alumina are treated with KH560 and then compounded with cerium oxide-based granules to form a third premix. The two are then compounded in stages under liquid-phase shear conditions to obtain a composite filler with good interfacial bonding. The different morphologies and functions of the components in this filler, through surface treatment, improve the interfacial compatibility with the polypropylene matrix, which is beneficial for the effective transfer of stress between the matrix and the filler, further enhancing the mechanical properties and weather resistance of the outer layer material. Attached Figure Description

[0017] Figure 1 The present invention provides a flowchart of a lightweight, high-toughness MPP composite cable protection pipe. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that the raw materials used in the following embodiments are all commercially available.

[0020] Example 1:

[0021] Lightweight, high-toughness MPP composite cable protection tubing, comprising a first composite material, a second composite material, and a third composite material; The first composite material comprises the following raw materials in parts by weight: 82 parts polypropylene resin, 7 parts filler, 2.2 parts polyolefin elastomer, 1.8 parts orange-red masterbatch, 1.3 parts antioxidant and 0.9 parts light stabilizer; The light stabilizer is composed of hindered amine light stabilizer and benzotriazole UV absorber in a mass ratio of 2:1.

[0022] The second composite material comprises the following raw materials in parts by weight: 72 parts polypropylene resin, 7 parts polyolefin elastomer, 3.5 parts SEBS-g-MAH, 10 parts basic magnesium sulfate whiskers, 7 parts hollow glass microspheres, 5.5 parts nano calcium carbonate, 0.07 parts β-crystal nucleating agent, 2.8 parts maleic anhydride grafted polypropylene and 0.9 parts antioxidant. Among them, the maleic anhydride grafting rate of SEBS-g-MAH is 1.2%, the styrene content is 30%, the maleic anhydride grafting rate of maleic anhydride-grafted polypropylene is 1.2%, and the antioxidant is composed of hindered phenolic antioxidant and phosphite antioxidant in a mass ratio of 1:2.

[0023] The third composite material comprises the following raw materials in parts by weight: 88 parts polypropylene resin, 2.5 parts polyolefin elastomer, 0.65 parts antioxidant, and 0.35 parts rutile titanium dioxide; The polypropylene resin used is impact-resistant copolymer polypropylene.

[0024] The pipe includes an outer layer, a middle layer, and an inner layer arranged sequentially from the outside to the inside along the radial direction of the pipe. The outer layer is formed of a first composite material, the middle layer is formed of a second composite material, and the inner layer is formed of a third composite material. The outer layer, the middle layer, and the inner layer are compositely connected in a molten state by a three-layer co-extrusion method. Based on the total pipe wall thickness, the outer layer accounts for 18% of the thickness, the inner layer accounts for 12% of the thickness, and the middle layer is the remaining thickness.

[0025] Preparation method: Preparation of filler: Hollow fine aluminosilicate microspheres were vacuum dried at 85℃ for 3 hours. KH550 was added to a mixture of ethanol and water to obtain the first silane treatment solution, wherein the volume ratio of KH550, ethanol, and water was 1:40:10. The dried hollow fine aluminosilicate microspheres were added to a low-shear mixing device, and the first silane treatment solution was atomized and sprayed into the dried hollow fine aluminosilicate microspheres at 58℃ and 60 rpm. After spraying, mixing continued for 15 minutes. The resulting product was vacuum dried at 85℃ for 2.5 hours to obtain the first premix. Needle-shaped wollastonite, flake-shaped monohydrated alumina, and granular material were dried separately and then mixed to obtain the second premix, wherein the mass ratio of needle-shaped wollastonite, flake-shaped monohydrated alumina, and granular material was 25:13:5. KH560 was added to a mixture of ethanol and water. A second silane treatment solution was obtained, wherein the volume ratio of KH560, ethanol, and water was 1:45:12. Under the conditions of a second premix temperature of 68℃ and a stirring speed of 140 rpm, the second silane treatment solution was atomized and sprayed into the second premix, and mixing continued for 20 min. The resulting product was vacuum dried at 100℃ for 3 h to obtain a third premix. The first premix was added to a 25% ethanol aqueous solution, controlling the solid content to 20%. Under shear conditions of 68℃ and 80 r / min, the third premix was added in four portions, with stirring continued for 15 min after each addition. After all the premix was added, the temperature was raised to 80℃, and the reaction was carried out for 1.5 h. The resulting product was filtered and vacuum dried at 88℃, then kept at 118℃ for 1.5 h to obtain the filler, wherein the mass ratio of the first premix to the third premix was 60:44.

[0026] Preparation of granules: Cerium oxide was added to a mixture of ethanol and water, mixed well, and then a nonionic dispersant was added. The mixture was continued to obtain a dispersion for later use. The mass ratio of cerium oxide, ethanol, water and nonionic dispersant was 1:4:1.4:0.3. Tetraethyl orthosilicate and ethanol were mixed at a mass ratio of 1:4 to obtain a mixture for later use. The mass of tetraethyl orthosilicate was 60-80% of the mass of cerium oxide. The pH of the dispersion was adjusted to 9. The mixture was added dropwise at 33°C with continuous stirring. After the addition was completed, the reaction was continued for 3 hours. The solid was obtained by centrifugation, washed with ethanol and deionized water respectively, and then vacuum dried at 90°C for 8 hours. After that, it was heat-treated at 400°C for 1.5 hours to obtain granules.

[0027] A method for preparing lightweight, high-toughness MPP composite cable protection pipe includes the following steps: First composite material, second composite material, and third composite material are melted and granulated separately, then added to an outer layer extruder, an intermediate layer extruder, and an inner layer extruder, respectively. The temperature of the outer layer material is 190℃, the temperature of the intermediate layer material is 195℃, the temperature of the inner layer material is 190℃, and the temperature of the co-extrusion die head is 198℃. The three melts converge in the co-extrusion die head and are extruded through an annular die, sequentially passing through an air precooling section, a first vacuum sizing and cooling section, and a second cooling section. The length of the air precooling section is 70mm. The cooling water temperature of the first vacuum sizing and cooling section is 42℃, and the cooling water temperature of the second cooling section is 24℃. After traction, cutting, and end-face processing, lightweight, high-toughness MPP composite cable protection pipe is obtained.

[0028] Example 2:

[0029] Lightweight, high-toughness MPP composite cable protection tubing, comprising a first composite material, a second composite material, and a third composite material; The first composite material comprises the following raw materials in parts by weight: 80 parts polypropylene resin, 6 parts filler, 2 parts polyolefin elastomer, 1.5 parts orange-red masterbatch, 1 part antioxidant and 0.8 parts light stabilizer; The light stabilizer is composed of hindered amine light stabilizer and benzotriazole UV absorber in a mass ratio of 2:1.

[0030] The second composite material comprises the following raw materials in parts by weight: 70 parts polypropylene resin, 6 parts polyolefin elastomer, 3 parts SEBS-g-MAH, 8 parts basic magnesium sulfate whiskers, 6 parts hollow glass microspheres, 5 parts nano calcium carbonate, 0.06 parts β-crystal nucleating agent, 2.5 parts maleic anhydride grafted polypropylene and 0.8 parts antioxidant. Among them, the maleic anhydride grafting rate of SEBS-g-MAH is 0.6%, the styrene content is 25%, the maleic anhydride grafting rate of maleic anhydride-grafted polypropylene is 0.8%, and the antioxidant is composed of hindered phenolic antioxidant and phosphite antioxidant in a mass ratio of 1:1.5.

[0031] The third composite material comprises the following raw materials in parts by weight: 85 parts polypropylene resin, 2 parts polyolefin elastomer, 0.5 parts antioxidant and 0.3 parts rutile titanium dioxide; The polypropylene resin used is impact-resistant copolymer polypropylene.

[0032] The pipe includes an outer layer, a middle layer, and an inner layer arranged sequentially from the outside to the inside along the radial direction of the pipe. The outer layer is formed of a first composite material, the middle layer is formed of a second composite material, and the inner layer is formed of a third composite material. The outer layer, the middle layer, and the inner layer are compositely connected in a molten state by a three-layer co-extrusion method. Based on the total thickness of the pipe wall, the outer layer accounts for 15% of the thickness, the inner layer accounts for 10% of the thickness, and the middle layer is the remaining thickness.

[0033] Preparation method: Preparation of filler: Hollow fine aluminosilicate microspheres were vacuum dried at 80℃ for 2 hours. KH550 was added to a mixture of ethanol and water to obtain the first silane treatment solution, wherein the volume ratio of KH550, ethanol, and water was 1:35:8. The dried hollow fine aluminosilicate microspheres were added to a low-shear mixing device, and the first silane treatment solution was atomized and sprayed into the dried hollow fine aluminosilicate microspheres at 50℃ and 40 rpm. After spraying, mixing continued for 10 minutes. The resulting product was vacuum dried at 80℃ for 2 hours to obtain the first premix. Needle-shaped wollastonite, flake-shaped monohydrated alumina, and granular material were dried separately and then mixed to obtain the second premix, wherein the mass ratio of needle-shaped wollastonite, flake-shaped monohydrated alumina, and granular material was 23:11:4. KH560 was added to the mixture of ethanol and water. A second silane treatment solution was obtained, wherein the volume ratio of KH560, ethanol, and water was 1:40:10. Under the conditions of 60℃ and 100rpm for the second premix, the second silane treatment solution was atomized and sprayed into the second premix, and the mixture was continued to be mixed for 15min. The resulting product was vacuum dried at 90℃ for 2h to obtain a third premix. The first premix was added to a 25% ethanol aqueous solution, and the solid content was controlled to be 15%. Under the shear conditions of 60℃ and 60r / min, the third premix was added in 3 portions, and the mixture was stirred for 10min after each addition. After all the premix was added, the temperature was raised to 75℃ and the reaction was carried out for 1h. The resulting product was filtered and vacuum dried at 80℃, and then kept at 110℃ for 1h to obtain the filler, wherein the mass ratio of the first premix to the third premix was 60:40.

[0034] Preparation of granules: Cerium oxide was added to a mixture of ethanol and water, mixed well, and then a nonionic dispersant was added. The mixture was further mixed to obtain a dispersion, which was set aside for use. The mass ratio of cerium oxide, ethanol, water and nonionic dispersant was 1:3.5:1.3:0.2. Tetraethyl orthosilicate and ethanol were mixed at a mass ratio of 1:3 to obtain a mixture, which was set aside for use. The mass of tetraethyl orthosilicate was 60% of the mass of cerium oxide. The pH of the dispersion was adjusted to 8.5. The mixture was added dropwise at 25°C with continuous stirring. After the addition was complete, the reaction was continued for 2 hours. The solid was obtained by centrifugation, washed with ethanol and deionized water respectively, and then vacuum dried at 80°C for 6 hours. After that, it was heat-treated at 350°C for 1 hour to obtain granules.

[0035] A method for preparing lightweight, high-toughness MPP composite cable protection pipe includes the following steps: First composite material, second composite material, and third composite material are melted and granulated separately, then added to an outer layer extruder, an intermediate layer extruder, and an inner layer extruder, respectively. The temperature of the outer layer material is 180℃, the temperature of the intermediate layer material is 185℃, the temperature of the inner layer material is 180℃, and the temperature of the co-extrusion die head is 190℃. The three melts converge in the co-extrusion die head and are extruded through an annular die, sequentially passing through an air precooling section, a first vacuum sizing and cooling section, and a second cooling section. The length of the air precooling section is 30mm. The cooling water temperature of the first vacuum sizing and cooling section is 35℃, and the cooling water temperature of the second cooling section is 18℃. After traction, cutting, and end-face processing, lightweight, high-toughness MPP composite cable protection pipe is obtained.

[0036] Example 3:

[0037] Lightweight, high-toughness MPP composite cable protection tubing, comprising a first composite material, a second composite material, and a third composite material; The first composite material comprises the following raw materials in parts by weight: 85 parts polypropylene resin, 8 parts filler, 2.5 parts polyolefin elastomer, 2 parts orange-red masterbatch, 1.5 parts antioxidant and 1 part light stabilizer; The light stabilizer is composed of hindered amine light stabilizer and benzotriazole UV absorber in a mass ratio of 2:1.

[0038] The second composite material comprises the following raw materials in parts by weight: 75 parts polypropylene resin, 8 parts polyolefin elastomer, 4 parts SEBS-g-MAH, 12 parts basic magnesium sulfate whiskers, 8 parts hollow glass microspheres, 6 parts nano calcium carbonate, 0.08 parts β-crystal nucleating agent, 3 parts maleic anhydride grafted polypropylene and 1 part antioxidant. Among them, the maleic anhydride grafting rate of SEBS-g-MAH is 1.5%, the styrene content is 35%, the maleic anhydride grafting rate of maleic anhydride-grafted polypropylene is 1.5%, and the antioxidant is composed of hindered phenolic antioxidant and phosphite antioxidant in a mass ratio of 1:2.5.

[0039] The third composite material comprises the following raw materials in parts by weight: 90 parts polypropylene resin, 3 parts polyolefin elastomer, 0.8 parts antioxidant and 0.4 parts rutile titanium dioxide; The polypropylene resin used is impact-resistant copolymer polypropylene.

[0040] The pipe includes an outer layer, a middle layer, and an inner layer arranged sequentially from the outside to the inside along the radial direction of the pipe. The outer layer is formed of a first composite material, the middle layer is formed of a second composite material, and the inner layer is formed of a third composite material. The outer layer, the middle layer, and the inner layer are compositely connected in a molten state by a three-layer co-extrusion method. Based on the total thickness of the pipe wall, the outer layer accounts for 20% of the thickness, the inner layer accounts for 15% of the thickness, and the middle layer is the remaining thickness.

[0041] Preparation method: Preparation of filler: Hollow fine aluminosilicate microspheres were vacuum dried at 90℃ for 4 hours. KH550 was added to a mixture of ethanol and water to obtain the first silane treatment solution, wherein the volume ratio of KH550, ethanol, and water was 1:45:12. The dried hollow fine aluminosilicate microspheres were added to a low-shear mixer. The first silane treatment solution was atomized and sprayed into the dried hollow fine aluminosilicate microspheres at 65℃ and 80 rpm. After spraying, mixing continued for 20 minutes. The resulting product was vacuum dried at 90℃ for 3 hours to obtain the first premix. Needle-shaped wollastonite, flake-shaped monohydrated alumina, and granular material were dried separately and then mixed to obtain the second premix, wherein the mass ratio of needle-shaped wollastonite, flake-shaped monohydrated alumina, and granular material was 28:15:6. KH560 was added to a mixture of ethanol and water. A second silane treatment solution was obtained, wherein the volume ratio of KH560, ethanol, and water was 1:50:15. Under the conditions of a second premix temperature of 75℃ and a stirring speed of 180 rpm, the second silane treatment solution was atomized and sprayed into the second premix, and mixing continued for 25 min. The resulting product was vacuum dried at 105℃ for 4 h to obtain a third premix. The first premix was added to a 25% ethanol aqueous solution, controlling the solid content to 25%. Under shear conditions of 75℃ and 100 r / min, the third premix was added in 5 portions, with stirring continued for 20 min after each addition. After all the premix was added, the temperature was raised to 85℃, and the reaction was carried out for 2 h. The resulting product was filtered and vacuum dried at 95℃, then kept at 125℃ for 2 h to obtain the filler, wherein the mass ratio of the first premix to the third premix was 60:48.

[0042] Preparation of granules: Cerium oxide was added to a mixture of ethanol and water, mixed well, and then a nonionic dispersant was added. The mixture was further mixed to obtain a dispersion, which was set aside for use. The mass ratio of cerium oxide, ethanol, water and nonionic dispersant was 1:4.5:1.5:0.4. Tetraethyl orthosilicate and ethanol were mixed at a mass ratio of 1:5 to obtain a mixture, which was set aside for use. The mass of tetraethyl orthosilicate was 80% of the mass of cerium oxide. The pH of the dispersion was adjusted to 9.5. The mixture was added dropwise at 40°C with continuous stirring. After the addition was complete, the reaction was continued for 4 hours. The solid was obtained by centrifugation, washed with ethanol and deionized water respectively, and then vacuum dried at 100°C for 10 hours. After that, it was heat-treated at 450°C for 2 hours to obtain granules.

[0043] A method for preparing lightweight, high-toughness MPP composite cable protection pipe includes the following steps: First composite material, second composite material, and third composite material are melted and granulated separately, then added to an outer layer extruder, an intermediate layer extruder, and an inner layer extruder, respectively. The temperature of the outer layer material is 200℃, the temperature of the intermediate layer material is 205℃, the temperature of the inner layer material is 200℃, and the temperature of the co-extrusion die head is 205℃. The three melts converge in the co-extrusion die head and are extruded through an annular die, sequentially passing through an air precooling section, a first vacuum sizing and cooling section, and a second cooling section. The length of the air precooling section is 100mm. The cooling water temperature of the first vacuum sizing and cooling section is 50℃, and the cooling water temperature of the second cooling section is 30℃. After traction, cutting, and end-face processing, a lightweight, high-toughness MPP composite cable protection pipe is obtained.

[0044] Comparative Example 1: The difference between this comparative example and Example 1 is that an equal amount of hollow glass microspheres are used to replace the filler in this comparative example.

[0045] Comparative Example 2 differs from Example 1 in that an equal amount of nano-silica is used to replace the granular material in this comparative example.

[0046] Comparative Example 3 differs from Example 1 in that SEBS-g-MAH and β-crystal nucleating agent are missing in this comparative example.

[0047] Performance testing: The composite cable protection pipes prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance testing.

[0048] Cantilever beam notched impact strength test: The test was conducted in accordance with ASTM D256-2024. The test specimens were directly cut from the axial direction of the pipe. The specimen size was 63.5mm × 12.7mm × pipe wall thickness, with a type A notch. The pendulum energy was 2.75J. The test was conducted at room temperature of 23±2℃. Each group of specimens consisted of no less than 10 specimens. The arithmetic mean was recorded in Table 1. Drop hammer impact test: The test was conducted in accordance with GB / T14152-2001 standard. The finished pipe was used as the test specimen. The specimen length was 200 mm, the hammer type was D90, the drop hammer mass was 3.0 kg, the impact height was 2.0 m, and the test was conducted at room temperature of 23±2℃. Each group of specimens had no less than 10 segments. The true impact rate (TIR) ​​of the specimens was recorded in Table 1.

[0049] Table 1: Performance test data for each embodiment and comparative example

[0050] In the performance test, all data of Examples 1-3 were better than those of Comparative Examples 1-3, which shows that the pipe proposed in this invention exhibits excellent comprehensive impact resistance while achieving lightweight, and effectively balances lightweight and high toughness.

[0051] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0052] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A lightweight, high-toughness MPP composite cable protection pipe, characterized in that: It consists of a first composite material, a second composite material, and a third composite material; The first composite material comprises the following raw materials in parts by weight: 80-85 parts polypropylene resin, 6-8 parts filler, 2-2.5 parts polyolefin elastomer, 1.5-2 parts orange-red masterbatch, 1-1.5 parts antioxidant and 0.8-1 parts light stabilizer; The second composite material comprises the following raw materials in parts by weight: 70-75 parts polypropylene resin, 6-8 parts polyolefin elastomer, 3-4 parts SEBS-g-MAH, 8-12 parts basic magnesium sulfate whiskers, 6-8 parts hollow glass microspheres, 5-6 parts nano calcium carbonate, 0.06-0.08 parts β-crystal nucleating agent, 2.5-3 parts maleic anhydride grafted polypropylene, and 0.8-1 parts antioxidant; The third composite material comprises the following raw materials in parts by weight: 85-90 parts polypropylene resin, 2-3 parts polyolefin elastomer, 0.5-0.8 parts antioxidant, and 0.3-0.4 parts rutile titanium dioxide; The polypropylene resin used is impact-resistant copolymer polypropylene.

2. The lightweight, high-toughness MPP composite cable protection conduit according to claim 1, characterized in that, The pipe includes an outer layer, a middle layer and an inner layer arranged sequentially from the outside to the inside along the radial direction of the pipe. The outer layer is formed of a first composite material, the middle layer is formed of a second composite material, and the inner layer is formed of a third composite material. The outer layer, the middle layer and the inner layer are compositely connected in the molten state by a three-layer co-extrusion method. Based on the total thickness of the pipe wall, the outer layer accounts for 15-20% of the thickness, the inner layer accounts for 10-15% of the thickness, and the middle layer is the remaining thickness.

3. The lightweight, high-toughness MPP composite cable protection conduit according to claim 1, characterized in that, The filler is prepared by the following method: hollow fine aluminosilicate microspheres are vacuum dried at 80-90℃ for 2-4 hours; KH550 is added to a mixture of ethanol and water to obtain a first silane treatment solution; the dried hollow fine aluminosilicate microspheres are added to a low-shear mixing device, and the first silane treatment solution is atomized and sprayed into the dried hollow fine aluminosilicate microspheres at 50-65℃ and 40-80 rpm; after spraying, mixing continues for 10-20 minutes; the resulting product is vacuum dried at 80-90℃ for 2-3 hours to obtain a first premix; needle-shaped wollastonite, flake-shaped monohydrate alumina, and granular material are dried separately and then mixed to obtain a second premix; KH560 is added to a mixture of ethanol and water to obtain a second silane treatment solution; in the second... Under the conditions of a premix temperature of 60-75℃ and a stirring speed of 100-180rpm, the second silane treatment liquid is atomized and sprayed into the second premix, and mixing is continued for 15-25min. The resulting product is vacuum dried at 90-105℃ for 2-4h to obtain the third premix. The first premix is ​​added to a 25% ethanol aqueous solution, and the solid content is controlled at 15-25%. Under the shear conditions of 60-75℃ and 60-100r / min, the third premix is ​​added in 3-5 portions, and stirring is continued for 10-20min after each addition. After all the premix is ​​added, the temperature is raised to 75-85℃ and the reaction is carried out for 1-2h. The resulting product is filtered and vacuum dried at 80-95℃, and then kept at 110-125℃ for 1-2h to obtain the filler.

4. The lightweight, high-toughness MPP composite cable protection conduit according to claim 1, characterized in that, The granules are prepared by the following method: Cerium oxide is added to a mixture of ethanol and water, mixed well, and then a nonionic dispersant is added. The mixture is further mixed to obtain a dispersion, which is then set aside. Tetraethyl orthosilicate is mixed with ethanol to obtain a mixture, which is then set aside. The pH of the dispersion is adjusted to 8.5-9.

5. The mixture is added dropwise at 25-40℃ with continuous stirring. After the addition is complete, the reaction continues for 2-4 hours. The solid is obtained by centrifugation, washed with ethanol and deionized water respectively, and then vacuum dried at 80-100℃ for 6-10 hours. After that, it is heat-treated at 350-450℃ for 1-2 hours to obtain the granules.

5. The lightweight, high-toughness MPP composite cable protection conduit according to claim 3, characterized in that, The volume ratio of KH550, ethanol, and water in the first silane treatment solution is 1:35-45:8-12; the volume ratio of KH560, ethanol, and water in the second silane treatment solution is 1:40-50:10-15; the mass ratio of acicular wollastonite, flaky monohydrate alumina, and granular material is 23-28:11-15:4-6; and the mass ratio of the first premix to the third premix is ​​60:40-48.

6. The lightweight, high-toughness MPP composite cable protection conduit according to claim 4, characterized in that, The mass ratio of cerium oxide, ethanol, water and nonionic dispersant is 1:3.5-4.5:1.3-1.5:0.2-0.4, the mass ratio of cerium oxide to tetraethyl orthosilicate is 1:0.6-0.8, and the mass ratio of tetraethyl orthosilicate to ethanol is 1:3-5.

7. The lightweight, high-toughness MPP composite cable protection conduit according to claim 1, characterized in that, The maleic anhydride grafting rate of SEBS-g-MAH is 0.6-1.5%, and the styrene content is 25-35% by mass. The maleic anhydride grafting rate of maleic anhydride-grafted polypropylene is 0.8-1.5%.

8. The lightweight, high-toughness MPP composite cable protection conduit according to claim 1, characterized in that, The light stabilizer is composed of hindered amine light stabilizer and benzotriazole UV absorber in a mass ratio of 2:

1.

9. The lightweight, high-toughness MPP composite cable protection conduit according to claim 1, characterized in that, The antioxidant is composed of hindered phenolic antioxidant and phosphite antioxidant in a mass ratio of 1:1.5-2.

5.

10. The method for preparing the lightweight, high-toughness MPP composite cable protection conduit according to any one of claims 1-9, characterized in that, The process includes the following steps: First composite material, second composite material, and third composite material are melted and granulated separately, then added to an outer layer extruder, an intermediate layer extruder, and an inner layer extruder, respectively. The temperature of the outer layer material is 180-200℃, the temperature of the intermediate layer material is 185-205℃, the temperature of the inner layer material is 180-200℃, and the temperature of the co-extrusion die head is 190-205℃. The three melts converge in the co-extrusion die head and are extruded through an annular die, sequentially passing through an air precooling section, a first vacuum sizing and cooling section, and a second cooling section. The length of the air precooling section is 30-100mm. The cooling water temperature of the first vacuum sizing and cooling section is 35-50℃, and the cooling water temperature of the second cooling section is 18-30℃. After traction, cutting, and end-face processing, a lightweight, high-toughness MPP composite cable protection pipe is obtained.

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