Wear-resistant flame-retardant modified polypropylene cable protection pipe and preparation method thereof

Abstract

The application belongs to the technical field of high-performance polypropylene cable materials, and particularly relates to a wear-resistant and flame-retardant modified polypropylene cable protection pipe and a preparation method thereof. The preparation method of the wear-resistant and flame-retardant modified polypropylene cable protection pipe comprises the following steps: S1, mixing polypropylene powder and modified POSS to perform grafting reaction to obtain high-performance polypropylene; S2, adding the high-performance polypropylene, inorganic fillers, polyethylene material, a compatilizer, a lubricant and an antioxidant into a mixer to stir to obtain a blended material; and S3, extruding the blended material through a screw extruder to be formed, sizing, and cooling to obtain a modified polypropylene plastic cable protection pipe. Through the synergistic effect of the components, the material strength is ensured, and good wear resistance and flame retardance are realized.

Description

Technical Field

[0001] This invention belongs to the technical field of high-performance polypropylene cable materials, specifically relating to a wear-resistant and flame-retardant modified polypropylene cable protection pipe and its preparation method. Background Technology

[0002] Ultra-high voltage (UHV) AC / DC transmission is a crucial technology for meeting my country's demand for ultra-large capacity and ultra-long-distance power transmission and implementing the West-to-East Power Transmission strategy. High-voltage direct current (HVDC) transmission technology boasts advantages such as low energy loss, long transmission distance, and suitability for large-capacity transmission. In recent years, my country has vigorously developed HVDC transmission projects, and this technology will play a key role in the energy sector. Currently, cross-linked polyethylene (XLPE) is widely used as insulation material for power cables. However, XLPE is a thermosetting plastic that cannot be repeatedly processed and reused after molding. The disposal of waste materials not only wastes resources but also poses environmental pollution risks. Furthermore, the manufacturing process of XLPE cables involves cross-linking and degassing, increasing energy consumption and carbon emissions. Byproducts of the cross-linking reaction may also remain in the insulation layer, leading to a decline in the material's electrical performance.

[0003] Against this backdrop, the development and research of thermoplastic polypropylene (PP) cable materials have attracted widespread attention. PP cables do not require cross-linking during production, simplifying the process, avoiding impurities generated during cross-linking, and reducing energy consumption and costs. As a thermoplastic material, PP can be recycled and reused after decommissioning, avoiding environmental pollution and resource waste, meeting environmental protection and recyclability requirements, and demonstrating promising development prospects. PP has a high melting point, can withstand long-term high operating temperatures, and possesses high breakdown field strength and volume resistivity, which is significant for improving cable voltage operating levels and current carrying capacity.

[0004] Chinese Patent (Publication No. CN121249052B) discloses a modified polypropylene plastic cable protection pipe and its preparation method. This modified polypropylene plastic cable protection pipe comprises the following components by weight: 70-100 parts polypropylene masterbatch, 20-40 parts modified polypropylene, 0.3-2 parts lubricant, 0.5-2 parts stabilizer, and 0.1-0.5 parts pigment. The modified polypropylene is obtained by blending polypropylene masterbatch, styrene block copolymer, functional additives, and lubricant. The modified polypropylene plastic cable protection pipe prepared by this invention has high ring stiffness and Vicat softening temperature. Furthermore, its flattening test, drop hammer impact test, and aging resistance all pass, indicating strong resistance to external pressure, good mechanical properties, high toughness, and resistance to cracking or damage. It also exhibits good aging resistance and a long service life. However, this patented technology lacks research on wear resistance, and its flame retardant performance has room for improvement, making it unsuitable for applications in extreme environments.

[0005] Therefore, there is an urgent need for a wear-resistant and flame-retardant modified polypropylene cable protection pipe. By modifying polypropylene to obtain high-performance polypropylene, and combining it with the use of functional inorganic fillers, good wear resistance and flame retardant properties can be achieved while ensuring material strength. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a wear-resistant and flame-retardant modified polypropylene cable protection pipe and its preparation method. The invention uses polypropylene powder and modified POSS as raw materials to obtain high-performance polypropylene. Then, the high-performance polypropylene, inorganic filler, polyethylene material, compatibilizer, lubricant, and antioxidant are added to a mixer and stirred to obtain a blend. This blend is then extruded using a screw extruder, sized, and cooled to obtain the modified polypropylene plastic cable protection pipe. Through the synergistic effect of the components, the wear quality during the wear resistance test is reduced, and the oxygen index of the material is effectively improved.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, this invention provides a method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe, comprising the following steps: S1. Polypropylene powder and modified POSS are mixed and grafted to obtain high-performance polypropylene; S2. Add the high-performance polypropylene, inorganic filler, polyethylene material, compatibilizer, lubricant, and antioxidant to a mixer and stir to obtain a blend. S3. The blend material described in step S2 is extruded and shaped using a screw extruder, sized, and cooled to obtain a modified polypropylene plastic cable protection pipe.

[0008] As a preferred technical solution of the present invention, the stirring conditions in step S2 are: stirring rate of 600~700 r / min and stirring time of 50~60 min.

[0009] As a preferred technical solution of the present invention, the extrusion molding conditions in step S3 are: temperature of 190~210℃, screw speed of 200~220r / min, and feeding speed of 200~210r / min.

[0010] As a preferred technical solution of the present invention, the sizing conditions in step S3 are: inner diameter of 200mm and wall thickness of 17mm.

[0011] As a preferred embodiment of the present invention, each component comprises, by weight: 80-90 parts high-performance polypropylene, 20-30 parts inorganic filler, 8-12 parts polyethylene material, 4-8 parts compatibilizer, 1-3 parts lubricant, and 0.4-0.6 parts antioxidant.

[0012] As a preferred embodiment of the present invention, the weight parts of the high-performance polypropylene may be 80 parts, 82 parts, 84 parts, 86 parts, 88 parts, or 90 parts, etc.

[0013] As a preferred embodiment of the present invention, the inorganic filler may be in the following weight proportions: 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, or 30 parts, etc.

[0014] As a preferred embodiment of the present invention, the weight parts of the polyethylene material may be 8 parts, 9 parts, 10 parts, 11 parts or 12 parts, etc.

[0015] As a preferred embodiment of the present invention, the compatibilizer may be expressed in parts by weight of 4, 5, 6, 7 or 8, etc.

[0016] As a preferred embodiment of the present invention, the lubricant may be 1 part, 2 parts or 3 parts by weight, etc.

[0017] As a preferred embodiment of the present invention, the antioxidant may be present in parts by weight of 0.4 parts, 0.5 parts, or 0.6 parts, etc.

[0018] As a preferred embodiment of the present invention, the grafting reaction step is as follows: by weight, 90-100 parts of polypropylene powder are placed in a reaction vessel, 8-10 parts of modified POSS and 1.2-1.6 parts are added under a nitrogen atmosphere, and the temperature is raised to 175-185°C for grafting reaction for 4-6 hours to obtain high-performance polypropylene.

[0019] As a preferred technical solution of the present invention, the preparation steps of the modified POSS are as follows: by weight, 50-60 parts of octavinyloctasilsesquioxane are added to 400-500 parts of dichloromethane and stirred at -35°C for 30-40 min, then 60-70 parts of 3-chloroperoxybenzoic acid are added and stirred for 12-14 h, the filtrate is collected by filtration, rotary evaporation is performed, and vacuum drying is performed to obtain intermediate product A; 50-60 parts of intermediate product A and 400-500 parts of tetrahydrofuran are mixed, then 20-30 parts of polyetheramine are added, and the mixture is reacted at 50-60°C for 8-10 h under a nitrogen atmosphere, rotary evaporation is performed, and vacuum drying is performed to obtain modified POSS.

[0020] This invention uses octavinyloctasilsesquioxane as a raw material, first epoxidizing it with 3-chloroperoxybenzoic acid and some of the double bonds, and then performing ring-opening addition with polyetheramine to prepare a reactive POSS derivative containing polyetheramine segments.

[0021] This invention uses polypropylene powder and modified POSS as reaction raw materials. Benzoyl peroxide, the initiator, decomposes into free radicals under heating conditions, which abstract hydrogen atoms from the polypropylene main chain to form macromolecular free radicals. Then, the macromolecular free radicals and the vinyl double bonds of the octavinyl POSS undergo an addition reaction to complete the grafting process, thereby obtaining high-performance polypropylene grafted with POSS.

[0022] As a preferred embodiment of the present invention, the inorganic filler is alumina and aluminum hydroxide.

[0023] As a preferred embodiment of the present invention, the mass ratio of alumina to aluminum hydroxide in the inorganic filler is (1~2):1.

[0024] As a preferred embodiment of the present invention, the alumina is modified alumina; The modified alumina is prepared by first preparing a coupling modifier using vinyltrimethoxysilane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide as raw materials, and then using the coupling modifier to modify the nano-alumina to obtain modified alumina.

[0025] This invention first uses vinyltrimethoxysilane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as raw materials. Free radicals are generated by the thermal decomposition of azobisisobutyronitrile, which initiates a phosphorus-hydrogen addition reaction between the PH bond on DOPO and the carbon-carbon double bond of vinylsilane to prepare a phosphorus-containing silane coupling modifier. Then, the coupling modifier is used to graft and modify nano-alumina. The hydroxyl groups on the surface of alumina undergo dehydration condensation with the silanol groups generated by the hydrolysis of silane, thereby obtaining DOPO phosphorus-silicon synergistic modified nano-alumina filler.

[0026] As a preferred technical solution of the present invention, the preparation steps of the coupling modifier are as follows: by weight, 90-100 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are added to 200-220 parts of diethylene glycol dimethyl ether and stirred for 20-30 min. After heating to 75-85°C, 50-60 parts of vinyltrimethoxysilane and 0.6-0.8 parts of azobisisobutyronitrile are added and reacted for 24-28 h. The mixture is washed with cyclohexane and distilled under reduced pressure to obtain the coupling modifier.

[0027] As a preferred technical solution of the present invention, the modification treatment steps are as follows: by weight, 400-450 parts of anhydrous ethanol and 50-100 parts of deionized water are mixed, then 20-30 parts of the coupling modifier are added and the pH is adjusted to 3-4. The mixture is allowed to stand for hydrolysis for 60-80 minutes, then 8-12 parts of nano-alumina are added, the temperature is raised to 45-55°C and the mixture is stirred for 4-6 hours for modification treatment, filtered, washed with anhydrous ethanol, and dried under vacuum.

[0028] As a preferred embodiment of the present invention, the aluminum hydroxide is vinyl-modified aluminum hydroxide with a whiteness ≥97% and D. 50 The particle size is 0.5~2.5μm, and the moisture content is ≤0.5%.

[0029] The inorganic filler of the present invention uses a compound of alumina and aluminum hydroxide, wherein the alumina is preferably DOPO phosphorus-silicon synergistic modified nano alumina filler, and the aluminum hydroxide is preferably vinyl modified aluminum hydroxide. By controlling the mass ratio of the two, a good synergistic effect is achieved, thereby improving the overall performance of polypropylene cable protection pipe.

[0030] As a preferred embodiment of the present invention, the polyethylene material is chlorinated polyethylene rubber; the chlorine content of the chlorinated polyethylene rubber is 30~40%, the volatile content is ≤0.4%, the residue on a 0.9mm sieve is ≤2%, and the thermal decomposition temperature is ≥165℃.

[0031] The polyethylene material of this invention preferably uses chlorinated polyethylene rubber, and by controlling its chlorine content, volatile matter content, sieve residue and thermal decomposition temperature, its compatibility with polypropylene is ensured, thereby improving the overall performance of the cable protection pipe.

[0032] As a preferred embodiment of the present invention, the compatibilizer is maleic anhydride-grafted polypropylene or maleic anhydride-grafted polyethylene.

[0033] As a preferred embodiment of the present invention, the lubricant is selected from one or more of calcium stearate, zinc stearate, oleamide, and polyethylene wax.

[0034] As a preferred embodiment of the present invention, the antioxidant is selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, and antioxidant BHT.

[0035] A second aspect of the present invention provides a wear-resistant and flame-retardant modified polypropylene cable protection pipe prepared by the preparation method described in the first aspect.

[0036] Compared with the prior art, the present invention has the following beneficial effects: (1) The high-performance polypropylene of the present invention introduces POSS groups through grafting reaction. The unique nanocage structure of POSS can effectively enhance the surface hardness and mechanical damage resistance of the polymer matrix, making it less prone to scratches and wear in complex construction environments, thereby reducing the wear quality of the material. When the material is burned, POSS will be thermally decomposed to form a dense protective carbon layer containing silicon on the surface of the material, effectively isolating heat and oxygen from being transferred to the interior, slowing down the further combustion of the matrix material, and improving the oxygen index of the cable protection pipe.

[0037] (2) The chlorinated polyethylene rubber of the present invention has good wear resistance, and the rubber phase can also elastically buffer friction stress, avoid direct scraping and wear of hard matrix, and significantly enhance the wear resistance of cable protection pipe; in addition, the chlorinated polyethylene rubber molecular chain contains chlorine atoms, which endows the material with natural flame retardancy and self-extinguishing properties, thereby effectively improving the flame retardant performance of the material.

[0038] (3) In the compound filler of the present invention, the organosilicon segments of modified alumina improve the interfacial compatibility with polypropylene matrix, and the nanoscale filling densifies the surface of the pipe, thereby reducing wear mass. At the same time, the grafted DOPO and organosilicon on the surface improve the oxygen index through phosphorus-silicon synergistic flame retardancy. On the other hand, the vinyl groups of vinyl-modified aluminum hydroxide can form weak crosslinks with the high-performance polypropylene matrix grafted with vinyl POSS, thereby reducing the mass loss caused by powder shedding during the friction process. At the same time, aluminum hydroxide decomposes and dehydrates when heated, absorbs heat and cools down, dilutes combustible gas and can capture free radicals to inhibit combustion, thereby improving the flame retardant performance of the material.

[0039] (4) The flexible segments of the modified POSS grafted with polyetheramine in this invention improve the self-lubricating properties of the material, and the flexible transfer film formed at the friction interface increases the wear resistance; in addition, the nitrogen element of polyetheramine has a synergistic effect, and the inert nitrogen gas released by thermal decomposition dilutes the combustible smoke, thereby improving the flame retardant performance. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 The image shows the FTIR spectra of the high-performance polypropylene and polypropylene powder in Example 1. Detailed Implementation

[0042] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0043] The sources of some components in the examples and comparative examples are as follows: Polypropylene powder, model PPH-T03, purchased from Maoming Petrochemical; Octavinyloctasilylsilsesquioxane, product number P102212, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Benzoyl peroxide, CAS No. 94-36-0, purchased from Sinopharm Chemical Reagent Co., Ltd. Nano-alumina, item number A498369, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Vinyltrimethoxysilane, CAS No. 2768-02-7, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, product number D102416, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Vinyl-modified aluminum hydroxide, model ATH-2, whiteness 97.5%, D 50 The particle size was 1.5 μm, and the moisture content was 0.4%. It was purchased from Guangdong Haike New Materials Technology Co., Ltd. Ordinary aluminum hydroxide, item number A1521041, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Chlorinated polyethylene rubber, model CM-35B, with a chlorine content of 35%, a volatile content of 0.35%, a 0.9mm sieve residue of 1.6%, and a thermal decomposition temperature of 166℃, was purchased from Jiangsu Tianteng Chemical Co., Ltd. Polyethylene micro powder, model UH010, was purchased from Nanjing Tengyi New Material Technology Co., Ltd. Maleic anhydride-grafted polypropylene, model 900P, purchased from Nanjing Feiteng New Material Technology Co., Ltd. Maleic anhydride-grafted polyethylene, model 900E, purchased from Nanjing Feiteng New Material Technology Co., Ltd. Calcium stearate, CAS No. 1592-23-0, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Zinc stearate, CAS No. 557-05-1, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Oleamide, CAS No. 301-02-0, purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Antioxidant 1010, CAS No. 6683-19-8, was purchased from Shandong Xiangdong New Material Technology Co., Ltd. Antioxidant 1076, CAS No. 2082-79-3, was purchased from Shandong Xiangdong New Material Technology Co., Ltd. Antioxidant 168, CAS No. 31570-04-4, was purchased from Shandong Xiangdong New Material Technology Co., Ltd.

[0044] Example 1

[0045] This embodiment provides a method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe, including the following steps: S1. By weight, 60 parts of octavinyloctasilsesquioxane were added to 500 parts of dichloromethane and stirred at -35°C for 40 min. Then, 70 parts of 3-chloroperoxybenzoic acid were added and stirred for 14 h. The filtrate was collected by filtration, rotary evaporation, and vacuum drying to obtain intermediate product A. 60 parts of intermediate product A and 500 parts of tetrahydrofuran were mixed, and then 30 parts of polyetheramine were added. The mixture was reacted at 60°C for 8 h under a nitrogen atmosphere, rotary evaporation, and vacuum drying to obtain modified POSS. 100 parts of polypropylene powder were placed in a reactor, and 10 parts of modified POSS and 1.6 parts of benzoyl peroxide were added under a nitrogen atmosphere. The temperature was raised to 185°C for a grafting reaction for 4 h to obtain high-performance polypropylene. The high-performance polypropylene and polypropylene powder were characterized and analyzed. The infrared spectra of the two are shown below. Figure 1 As shown.

[0046] S2. Add the 90 parts of high-performance polypropylene, 30 parts of inorganic filler (20 parts of modified alumina and 10 parts of vinyl modified aluminum hydroxide), 12 parts of polyethylene micro powder, 8 parts of compatibilizer maleic anhydride grafted polypropylene, 3 parts of lubricant calcium stearate, and 0.6 parts of antioxidant 1010 to a mixer and stir (stirring speed is 700 r / min, stirring time is 50 min) to obtain a blend.

[0047] S3. The blend material described in step S2 is extruded and shaped using a screw extruder (temperature 210℃, screw speed 220r / min, feeding speed 210r / min), sized (inner diameter 200mm, wall thickness 17mm), and cooled to obtain a modified polypropylene plastic cable protection pipe.

[0048] Preparation of modified alumina: By weight, 100 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were added to 220 parts of diethylene glycol dimethyl ether and stirred for 30 min. After heating to 85 °C, 60 parts of vinyltrimethoxysilane and 0.8 parts of azobisisobutyronitrile were added and reacted for 24 h. The mixture was washed with cyclohexane and distilled under reduced pressure to obtain a coupling modifier. 450 parts of anhydrous ethanol and 50 parts of deionized water were mixed, and then 30 parts of the coupling modifier were added and the pH was adjusted to 4. The mixture was allowed to stand for hydrolysis for 80 min, and then 12 parts of nano-alumina were added. The mixture was heated to 55 °C and stirred for 4 h for modification treatment. After filtration, the mixture was washed with anhydrous ethanol and dried under vacuum to obtain modified alumina.

[0049] Example 2

[0050] This embodiment provides a method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe, including the following steps: S1. By weight, 50 parts of octavinyloctasilsesquioxane were added to 400 parts of dichloromethane and stirred at -35°C for 30 min. Then, 60 parts of 3-chloroperoxybenzoic acid were added and stirred for 12 h. The filtrate was collected by filtration, rotary evaporation, and vacuum drying to obtain intermediate product A. 50 parts of intermediate product A and 400 parts of tetrahydrofuran were mixed, and then 20 parts of polyetheramine were added. The mixture was reacted at 50°C for 10 h under a nitrogen atmosphere. The mixture was then rotary evaporation and vacuum drying to obtain modified POSS. 90 parts of polypropylene powder were placed in a reactor, and 8 parts of modified POSS and 1.2 parts of benzoyl peroxide were added under a nitrogen atmosphere. The mixture was heated to 175°C for a grafting reaction for 6 h to obtain high-performance polypropylene.

[0051] S2. Add the 80 parts of high-performance polypropylene, 20 parts of inorganic filler (10 parts of modified alumina and 10 parts of vinyl modified aluminum hydroxide), 8 parts of polyethylene micro powder, 4 parts of compatibilizer maleic anhydride grafted polyethylene, 1 part of lubricant zinc stearate, and 0.4 parts of antioxidant 1076 to a mixer and stir (stirring speed is 600 r / min, stirring time is 60 min) to obtain a blend.

[0052] S3. The blend material described in step S2 is extruded and shaped using a screw extruder (temperature 190℃, screw speed 200r / min, feeding speed 200r / min), sized (inner diameter 200mm, wall thickness 17mm), and cooled to obtain a modified polypropylene plastic cable protection pipe.

[0053] Preparation of modified alumina: By weight, 90 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were added to 200 parts of diethylene glycol dimethyl ether and stirred for 20 min. After heating to 75 °C, 50 parts of vinyltrimethoxysilane and 0.6 parts of azobisisobutyronitrile were added and reacted for 28 h. The mixture was washed with cyclohexane and distilled under reduced pressure to obtain a coupling modifier. 400 parts of anhydrous ethanol and 100 parts of deionized water were mixed, and then 20 parts of the coupling modifier were added and the pH was adjusted to 3. The mixture was allowed to stand for hydrolysis for 80 min, and then 8 parts of nano-alumina were added. The mixture was heated to 45 °C and stirred for 6 h for modification treatment. After filtration, the mixture was washed with anhydrous ethanol and dried under vacuum to obtain modified alumina.

[0054] Example 3

[0055] This embodiment provides a method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe, including the following steps: S1. By weight, 55 parts of octavinyloctasilsesquioxane were added to 450 parts of dichloromethane and stirred at -35°C for 35 min. Then, 65 parts of 3-chloroperoxybenzoic acid were added and stirred for 13 h. The filtrate was collected by filtration, rotary evaporation, and vacuum drying to obtain intermediate product A. 55 parts of intermediate product A and 450 parts of tetrahydrofuran were mixed, and then 25 parts of polyetheramine were added. The mixture was reacted at 55°C for 9 h under a nitrogen atmosphere, rotary evaporation, and vacuum drying to obtain modified POSS. 95 parts of polypropylene powder were placed in a reactor, and 9 parts of modified POSS and 1.4 parts of benzoyl peroxide were added under a nitrogen atmosphere. The mixture was heated to 178°C for a grafting reaction for 5 h to obtain high-performance polypropylene.

[0056] S2. Add the 85 parts of high-performance polypropylene, 25 parts of inorganic filler (15 parts of modified alumina and 10 parts of vinyl modified aluminum hydroxide), 10 parts of polyethylene micro powder, 6 parts of compatibilizer maleic anhydride grafted polypropylene, 2 parts of lubricant oleamide, and 0.5 parts of antioxidant 168 to a mixer and stir (stirring speed is 650 r / min, stirring time is 55 min) to obtain a blend.

[0057] S3. The blend material described in step S2 is extruded and shaped using a screw extruder (temperature 200℃, screw speed 210r / min, feeding speed 205r / min), sized (inner diameter 200mm, wall thickness 17mm), and cooled to obtain a modified polypropylene plastic cable protection pipe.

[0058] Preparation of modified alumina: By weight, 95 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were added to 210 parts of diethylene glycol dimethyl ether and stirred for 25 min. After heating to 80 °C, 58 parts of vinyltrimethoxysilane and 0.7 parts of azobisisobutyronitrile were added and reacted for 26 h. The mixture was washed with cyclohexane and distilled under reduced pressure to obtain a coupling modifier. 420 parts of anhydrous ethanol and 80 parts of deionized water were mixed, and then 25 parts of the coupling modifier were added and the pH was adjusted to 3.5. The mixture was allowed to stand for hydrolysis for 70 min, and then 10 parts of nano-alumina were added. The mixture was heated to 48 °C and stirred for 5 h for modification treatment. After filtration, the mixture was washed with anhydrous ethanol and dried under vacuum to obtain modified alumina.

[0059] Example 4

[0060] This embodiment provides a method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe, including the following steps: S1. By weight, 60 parts of octavinyloctasilsesquioxane were added to 500 parts of dichloromethane and stirred at -35°C for 40 min. Then, 70 parts of 3-chloroperoxybenzoic acid were added and stirred for 14 h. The filtrate was collected by filtration, rotary evaporation, and vacuum drying to obtain intermediate product A. 60 parts of intermediate product A and 500 parts of tetrahydrofuran were mixed, and then 30 parts of polyetheramine were added. The mixture was reacted at 60°C for 8 h under a nitrogen atmosphere. The mixture was then rotary evaporation and vacuum drying to obtain modified POSS. 100 parts of polypropylene powder were placed in a reactor, and 10 parts of modified POSS and 1.6 parts of benzoyl peroxide were added under a nitrogen atmosphere. The mixture was heated to 185°C for a grafting reaction for 4 h to obtain high-performance polypropylene.

[0061] S2. Add the 90 parts of high-performance polypropylene, 30 parts of inorganic filler (20 parts of modified alumina and 10 parts of vinyl modified aluminum hydroxide), 12 parts of chlorinated polyethylene rubber, 8 parts of compatibilizer maleic anhydride grafted polypropylene, 3 parts of lubricant calcium stearate, and 0.6 parts of antioxidant 1010 to a mixer and stir (stirring speed is 700 r / min, stirring time is 50 min) to obtain a blend.

[0062] S3. The blend material described in step S2 is extruded and shaped using a screw extruder (temperature 210℃, screw speed 220r / min, feeding speed 210r / min), sized (inner diameter 200mm, wall thickness 17mm), and cooled to obtain a modified polypropylene plastic cable protection pipe.

[0063] Preparation of modified alumina: By weight, 100 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were added to 220 parts of diethylene glycol dimethyl ether and stirred for 30 min. After heating to 85 °C, 60 parts of vinyltrimethoxysilane and 0.8 parts of azobisisobutyronitrile were added and reacted for 24 h. The mixture was washed with cyclohexane and distilled under reduced pressure to obtain a coupling modifier. 450 parts of anhydrous ethanol and 50 parts of deionized water were mixed, and then 30 parts of the coupling modifier were added and the pH was adjusted to 4. The mixture was allowed to stand for hydrolysis for 80 min, and then 12 parts of nano-alumina were added. The mixture was heated to 55 °C and stirred for 4 h for modification treatment. After filtration, the mixture was washed with anhydrous ethanol and dried under vacuum to obtain modified alumina.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 1 is that polypropylene powder (model PPH-T03) is used instead of high-performance polypropylene.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 1 is that the inorganic filler was changed to 20 parts of nano alumina (item number A498369) and 10 parts of vinyl-modified aluminum hydroxide.

[0068] Comparative Example 3

[0069] The difference between this comparative example and Example 1 is that the inorganic filler was changed to 20 parts modified alumina and 10 parts ordinary aluminum hydroxide (item number A1521041).

[0070] Comparative Example 4

[0071] The difference between this comparative example and Example 1 is that the inorganic filler was replaced with 30 parts of modified alumina.

[0072] Comparative Example 5

[0073] The difference between this comparative example and Example 1 is that the inorganic filler was replaced with 30 parts of vinyl-modified aluminum hydroxide.

[0074] The performance of the above embodiments and comparative examples was tested using the following methods: (1) Abrasion resistance test: The test shall be conducted in accordance with the requirements of GB / T 3960-2016 Plastics sliding friction and wear test method.

[0075] (2) Oxygen index test: The test shall be conducted in accordance with the requirements of GB / T 2406.2-2009 Determination of combustion behavior of plastics by oxygen index method - Part 2: Room temperature test.

[0076] (3) Tensile strength test: The test shall be conducted in accordance with the requirements of GB / T 8804.3-2003 Thermoplastic Pipes - Determination of Tensile Properties - Part 3: Polyolefin Pipes.

[0077] (4) Bending strength test: The test shall be conducted in accordance with the requirements of GB / T 9341-2008 Determination of bending properties of plastics.

[0078] The performance test data above are shown in Table 1.

[0079] Table 1 Performance Test Results

[0080] As can be seen from the above, the present invention uses polypropylene powder and modified POSS as raw materials to produce high-performance polypropylene. Then, the high-performance polypropylene, inorganic filler, polyethylene material, compatibilizer, lubricant and antioxidant are added to a mixer and stirred to obtain a blend. The blend is then extruded and shaped by a screw extruder, sized, and cooled to obtain a modified polypropylene plastic cable protection pipe.

[0081] Compared with Example 1, chlorinated polyethylene rubber (model CM-35B) was used instead of polyethylene micro powder (model UH010). Due to the introduction of chlorinated polyethylene rubber, the wear mass of the material was reduced and the flame retardant performance was improved (Example 4). Compared with Example 1, the use of polypropylene powder (model PPH-T03) instead of high-performance polypropylene resulted in a lack of POSS groups introduced by high-performance polypropylene, which led to an increase in the wear quality of the material and a decrease in its flame retardant properties (Comparative Example 1). Compared with Example 1, the inorganic filler was changed to 20 parts of nano alumina (item number A498369) and 10 parts of vinyl modified aluminum hydroxide. Without the effect of modified alumina, the wear quality of the material increased and the flame retardant performance deteriorated (Comparative Example 2). Compared with Example 1, the inorganic filler was changed to 20 parts modified alumina and 10 parts ordinary aluminum hydroxide (item number A1521041). Without the effect of vinyl modified aluminum hydroxide, the wear quality of the material increased and the flame retardant performance deteriorated (Comparative Example 3). Compared with Example 1, the inorganic filler was replaced with 30 parts of modified alumina, and the compound of vinyl-modified aluminum hydroxide was missing, which increased the wear quality of the material and worsened the flame retardant performance (Comparative Example 4). Compared with Example 1, the inorganic filler was replaced with 30 parts of vinyl-modified aluminum hydroxide. The lack of modified aluminum oxide compounding resulted in increased wear quality and poorer flame retardant performance of the material (Comparative Example 5).

Claims

1. A method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe, characterized in that, Includes the following steps: S1. Polypropylene powder and modified POSS are mixed and grafted to obtain high-performance polypropylene; S2. Add the high-performance polypropylene, inorganic filler, polyethylene material, compatibilizer, lubricant, and antioxidant to a mixer and stir to obtain a blend. S3. The blend material described in step S2 is extruded and shaped using a screw extruder, sized, and cooled to obtain a modified polypropylene plastic cable protection pipe.

2. The method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe according to claim 1, characterized in that, The components, by weight, include: 80-90 parts high-performance polypropylene, 20-30 parts inorganic filler, 8-12 parts polyethylene material, 4-8 parts compatibilizer, 1-3 parts lubricant, and 0.4-0.6 parts antioxidant.

3. The method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe according to claim 1, characterized in that, The grafting reaction steps are as follows: by weight, 90-100 parts of polypropylene powder are placed in a reaction vessel, 8-10 parts of modified POSS and 1.2-1.6 parts of benzoyl peroxide are added under a nitrogen atmosphere, and the temperature is raised to 175-185℃ for grafting reaction for 4-6 hours to obtain high-performance polypropylene. The preparation steps of the modified POSS are as follows: by weight, 50-60 parts of octavinyloctasilsesquioxane are added to 400-500 parts of dichloromethane and stirred at -35°C for 30-40 min, then 60-70 parts of 3-chloroperoxybenzoic acid are added and stirred for 12-14 h, the filtrate is collected by filtration, rotary evaporation is performed, and vacuum drying is performed to obtain intermediate product A; 50-60 parts of intermediate product A and 400-500 parts of tetrahydrofuran are mixed, then 20-30 parts of polyetheramine are added, and the mixture is reacted at 50-60°C for 8-10 h under a nitrogen atmosphere, rotary evaporation is performed, and vacuum drying is performed to obtain modified POSS.

4. The method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe according to claim 1, characterized in that, The inorganic filler is aluminum oxide and aluminum hydroxide; The mass ratio of alumina to aluminum hydroxide in the inorganic filler is (1~2):

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5. The method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe according to claim 4, characterized in that, The alumina is modified alumina; The modified alumina is prepared by first preparing a coupling modifier using vinyltrimethoxysilane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide as raw materials, and then using the coupling modifier to modify the nano-alumina to obtain modified alumina.

6. The method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe according to claim 5, characterized in that, The preparation steps of the coupling modifier are as follows: by weight, 90-100 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are added to 200-220 parts of diethylene glycol dimethyl ether and stirred for 20-30 min. After heating to 75-85℃, 50-60 parts of vinyltrimethoxysilane and 0.6-0.8 parts of azobisisobutyronitrile are added and reacted for 24-28 h. The mixture is washed with cyclohexane and distilled under reduced pressure to obtain the coupling modifier.

7. The method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe according to claim 5, characterized in that, The modification process is as follows: by weight, 400-450 parts of anhydrous ethanol and 50-100 parts of deionized water are mixed, then 20-30 parts of the coupling modifier are added and the pH is adjusted to 3-4. The mixture is allowed to stand for hydrolysis for 60-80 minutes, then 8-12 parts of nano-alumina are added. The mixture is heated to 45-55°C and stirred for 4-6 hours for modification treatment. The mixture is then filtered, washed with anhydrous ethanol, and dried under vacuum.

8. The method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe according to claim 4, characterized in that, The aluminum hydroxide is vinyl-modified aluminum hydroxide with a whiteness ≥97% and D. 50 The particle size is 0.5~2.5μm, and the moisture content is ≤0.5%.

9. The method for preparing a wear-resistant and flame-retardant modified polypropylene cable protection pipe according to claim 1, characterized in that, The polyethylene material is chlorinated polyethylene rubber; the chlorine content of the chlorinated polyethylene rubber is 30~40%, the volatile content is ≤0.4%, the residue on a 0.9mm sieve is ≤2%, and the thermal decomposition temperature is ≥165℃.

10. A wear-resistant and flame-retardant modified polypropylene cable protection pipe, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 9.

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