Aging-resistant cable protection pipe and preparation method thereof

Abstract

The application belongs to the technical field of high polymer compounds, and particularly relates to an anti-aging cable protection pipe and a preparation method thereof. The preparation method of the anti-aging cable protection pipe comprises the following steps: S1, first, cashew phenol and cyanuric chloride are used as raw materials to prepare modified cashew phenol, then the modified cashew phenol and polypropylene chips are mixed to carry out melt grafting, and grafted modified polypropylene is obtained; S2, the grafted modified polypropylene, fillers, maleic anhydride grafted polypropylene, a lubricant and an antioxidant are mixed to obtain a mixture, and the mixture is sent into a double-screw extruder to sequentially carry out melt plasticization, extrusion, sizing, cooling and traction, so that the anti-aging cable protection pipe is obtained. In the application, halogen is not introduced, the material has good flame-retardant performance, and the anti-aging performance is significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer compound technology, specifically relating to an aging-resistant cable protection tube and its preparation method. Background Technology

[0002] With industrial development and accelerated urbanization, the advantages of power cables in power transmission have become increasingly prominent. Compared to overhead lines, power cables are typically installed underground or in other concealed locations, making them less susceptible to damage from external forces, thus improving power supply security and reducing land occupation. In engineering construction, the selection of cable protection pipes is a key factor in ensuring the safety of power transmission. Firstly, cable protection pipes possess sufficient mechanical strength to prevent cable damage; furthermore, they are primarily installed at intersections of communication cables and power lines to prevent short circuits caused by power line breaks, protecting cables, switches, circuit boards, and even the entire device from damage.

[0003] Cable protection pipes can be mainly divided into three categories according to their materials: metal pipes, plastic pipes and composite material pipes. Among them, the most widely used plastic pipes can be further subdivided into the following three types: (1) Polypropylene (PP) protection pipes, which have the characteristics of high temperature resistance, high pressure resistance and excellent insulation performance, support trenchless construction, and are an efficient choice for railway lines and trenchless power networks; (2) High-density polyethylene (HDPE) protection pipes, which have excellent corrosion resistance, wear resistance and anti-aging performance; (3) Polyvinyl chloride (PVC) protection pipes are low in cost and easy to construct. They have high heat resistance and pressure resistance and are suitable for environments such as tunnels and underground parking lots.

[0004] Chinese Patent (Announcement No. CN121182107B) discloses a high-temperature resistant and flame-retardant CPVC power cable protection pipe and its preparation method. The high-temperature resistant and flame-retardant CPVC power cable protection pipe comprises at least the following raw materials in parts by weight: 90-100 parts of chlorinated polyvinyl chloride; 15-25 parts of high-impact MCS resin; 1-2 parts of polyadipate; 8-12 parts of propylene glycol ester; 12-20 parts of sepiolite-methyl methacrylate-butyl acrylate composite; 8-15 parts of aluminum-titanium composite coupling agent modified magnesium aluminum lanthanum hydrotalcite; 3-6 parts of rare earth composite heat stabilizer; 2-4 parts of processing aid; 0.5-1.5 parts of antioxidant; and 1-2 parts of lubricant. The high-temperature resistant and flame-retardant CPVC power cable protection pipe prepared by this invention has high heat resistance, high flame retardancy, and high impact resistance, exhibiting excellent comprehensive performance, high safety and reliability, and long service life. However, this patented technology uses chlorinated polyvinyl chloride as a base material, which contains halogens and releases a large amount of toxic gases under high temperature conditions. At the same time, it lacks research on anti-aging properties.

[0005] Therefore, there is an urgent need for an aging-resistant cable protection pipe that uses polypropylene as the main substrate and functional components without introducing halogens, so as to ensure that the material has good flame retardant properties and significantly improve its anti-aging properties. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an aging-resistant cable protection pipe and its preparation method. The invention first prepares modified cashew phenol using cashew phenol and melamine chloride as raw materials. Then, the modified cashew phenol is mixed with polypropylene chips and melt-grafted to obtain grafted modified polypropylene. Magnesium hydroxide and attapulgite are used as compound fillers, along with maleic anhydride grafted polypropylene, lubricants, antioxidants, etc., for melt extrusion molding to obtain the aging-resistant cable protection pipe. This ensures the material has good flame retardancy and anti-aging properties without the use of halogens.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, the present invention provides a method for preparing an aging-resistant cable protection tube, comprising the following steps: S1. First, modified cashew phenol is prepared using cashew phenol and melamine chloride as raw materials. Then, the modified cashew phenol and polypropylene chips are mixed and melt-grafted to obtain grafted modified polypropylene. S2. Graft-modified polypropylene, filler, maleic anhydride-grafted polypropylene, lubricant, and antioxidant are mixed to obtain a mixture. The mixture is fed into a twin-screw extruder and subjected to melt plasticizing, extrusion, sizing, cooling, and traction in sequence to obtain an aging-resistant cable protection pipe.

[0008] As a preferred technical solution of the present invention, the set temperature conditions of the twin-screw extruder in step S2 are: zone 1 temperature 170~175℃, zone 2 temperature 180~185℃, zone 3 temperature 185~190℃, zone 4 temperature 190~195℃, and die head temperature 195~200℃.

[0009] As a preferred technical solution of the present invention, each component in step S2 includes, by weight: 80-90 parts of grafted modified polypropylene, 20-30 parts of filler, 6-8 parts of maleic anhydride grafted polypropylene, 1-2 parts of lubricant, and 0.4-0.6 parts of antioxidant.

[0010] As a preferred embodiment of the present invention, the grafted modified polypropylene may be in the following weight proportions: 80 parts, 82 parts, 84 parts, 86 parts, 88 parts, or 90 parts, etc.

[0011] As a preferred embodiment of the present invention, the weight fraction of the filler may be 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, or 30 parts, etc.

[0012] As a preferred embodiment of the present invention, the weight parts of the maleic anhydride-grafted polypropylene can be 6 parts, 7 parts, or 8 parts, etc.

[0013] As a preferred embodiment of the present invention, the weight parts of the lubricant may be 1.0 parts, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, or 2.0 parts, etc.

[0014] 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.

[0015] As a preferred technical solution of the present invention, the preparation steps of the modified cashew nut phenol are as follows: by weight, 90-100 parts of cashew nut phenol, 30-40 parts of triethylamine and 18-20 parts of cyanuric chloride are added to 180-200 parts of N,N-dimethylformamide, stirred in an ice bath for 2-4 hours, then heated to 80-90°C and reacted for 100-120 minutes. After the reaction is completed, the mixture is cooled to room temperature, filtered to obtain the filtrate, rotary evaporated, washed with water, and dried to obtain the modified cashew nut phenol.

[0016] As a preferred embodiment of the present invention, the melt grafting step is as follows: 80-90 parts by weight of polypropylene chips, 10-20 parts of modified cashew nut shell powder and 1-2 parts of dicumyl peroxide are added to a twin-screw extruder, and melt grafting is performed at a temperature of 170-180°C and a screw speed of 30-40 r / min. The mixture is then washed with acetone and vacuum dried to obtain grafted modified polypropylene.

[0017] This invention uses cashew nut shellac and melamine as raw materials, and triethylamine as an acid-binding agent. The modified cashew nut shellac containing a triazine ring structure is prepared by nucleophilic substitution of the phenolic hydroxyl groups of cashew nut shellac with the chlorine atoms of melamine. Subsequently, during the melt grafting process, dicumyl peroxide decomposes to generate free radicals, which abstract tertiary hydrogens from the polypropylene molecular chain to generate macromolecular free radicals. These macromolecular free radicals graft onto the unsaturated active sites on the modified cashew nut shellac, thereby obtaining cashew nut shellac grafted modified polypropylene containing a triazine ring.

[0018] As a preferred embodiment of the present invention, the filler is magnesium hydroxide and attapulgite.

[0019] As a preferred embodiment of the present invention, the mass ratio of magnesium hydroxide to attapulgite in the filler is (1~2):1.

[0020] As a preferred embodiment of the present invention, the magnesium hydroxide is fatty acid-modified magnesium hydroxide with a specific surface area of ​​2-5 m². 2 / g, average particle size D 50 The thickness is 0.5~1.0μm, and the drying loss is 0.05~0.10%.

[0021] As a preferred embodiment of the present invention, the rettolith is a POSS intercalated rettolith composite material.

[0022] As a preferred technical solution of the present invention, the preparation method of the POSS intercalated attapulgite composite material is as follows: firstly, attapulgite powder and dicyandiamide are used as raw materials to prepare attapulgite composite material, and then aminopropylheptyl cage-like polysilsesquioxane is used to intercalate the attapulgite composite material to obtain the POSS intercalated attapulgite composite material.

[0023] This invention first mixes raptor powder and dicyandiamide and converts dicyandiamide into carbon nitride through a one-step pyrolysis method to obtain a raptor composite material with graphite carbon nitride. Then, the raptor composite material is intercalated with acidified aminopropylheptyl cage-like polysilsesquioxane to finally obtain a POSS intercalated raptor composite material.

[0024] As a preferred technical solution of the present invention, the preparation steps of the attapulgite composite material are as follows: by weight, 8-10 parts of dicyandiamide are added to 400-500 parts of deionized water and ultrasonicated for 30-40 minutes, then 8-10 parts of attapulgite powder are added and stirred for 15-25 minutes, then heated to 60-70℃ and stirred for 10-12 hours, dried, ground, and a precursor is obtained. The precursor is transferred to a tube furnace and calcined at 500-550℃ for 4-6 hours under an argon atmosphere. After cooling, it is washed with deionized water, filtered, and dried to obtain the attapulgite composite material.

[0025] As a preferred embodiment of the present invention, the intercalation treatment step is as follows: by weight, 4-6 parts of aminopropylheptyl cage-like polysilsesquioxane are added to 40-50 parts of tetrahydrofuran and stirred for 50-60 minutes, then 10-12 parts of 10% hydrochloric acid aqueous solution are added dropwise to obtain an intercalation treatment solution, 8-10 parts of attapulgite composite material are added to 180-200 parts of deionized water and stirred for 10-12 hours, then the intercalation treatment solution is added and stirred for 20-24 hours, filtered, washed with water, and vacuum dried to obtain POSS intercalated attapulgite composite material.

[0026] The filler of the present invention preferably uses a combination of fatty acid modified magnesium hydroxide and POSS intercalated attapulgite composite material. By controlling the mass ratio of the two, a good synergistic effect is ensured, thereby significantly improving the overall performance of the cable protection pipe.

[0027] As a preferred embodiment of the present invention, the lubricant is polyethylene wax or calcium stearate.

[0028] As a preferred embodiment of the present invention, the antioxidant is selected from one or more of antioxidant 1010, antioxidant 1098, and antioxidant 168.

[0029] A second aspect of the present invention provides an aging-resistant cable protection tube prepared by the preparation method described in the first aspect.

[0030] Compared with the prior art, the beneficial effects of the present invention are: (1) The grafted modified polypropylene of the present invention undergoes intramolecular condensation due to the thermal decomposition of the triazine ring under high temperature environment, and the cashew phenol aromatic ring is simultaneously dehydrated and crosslinked, rapidly generating a dense and continuous nitrogen-rich carbon layer on the surface of the pipe, which blocks the conduction of external heat to the inside and reduces the thermal decomposition rate of the matrix. Combined with the non-flammable gas released by the thermal decomposition of triazine, the flame retardant performance of the material is effectively improved. At the same time, the rigid structure of triazine ring and benzene ring can increase the steric hindrance of molecular chain, inhibit the molecular chain breakage and rearrangement at high temperature, thereby obtaining good heat aging resistance. (2) This invention uses fatty acid modified magnesium hydroxide and POSS intercalated attapulgite composite material as compound filler. At low temperature, fatty acid modified magnesium hydroxide absorbs heat and dehydrates to cool down. At the same time, carbon nitride in attapulgite composite material captures combustion free radicals to inhibit combustion. At high temperature, POSS, attapulgite sheets and magnesium hydroxide together construct a multi-layer dense composite barrier carbon layer. The triple flame retardant mechanism effectively improves the oxygen index of the material. On the other hand, after fatty acid surface modification, the surface polarity of magnesium hydroxide powder is greatly reduced, and the interfacial compatibility with the cable pipe resin matrix is ​​significantly improved. By being uniformly dispersed in the matrix, it effectively eliminates the interfacial gaps caused by filler agglomeration and blocks the heat and oxygen permeation channels. The multi-level sheet structure of POSS intercalated attapulgite constructs a macroscopic barrier to block heat and oxygen diffusion in space. Carbon nitride in composite material accurately captures aging active free radicals to terminate the aging chain reaction at the reaction level. The synergistic effect of the three significantly reduces the heat and oxygen degradation rate of the resin matrix and significantly improves the heat aging resistance of the cable protection pipe. Attached Figure Description

[0031] Figure 1 The image shows the FTIR spectra of the POSS intercalated attapulgite composite material and attapulgite powder in Example 1.

[0032] Figure 2 The image shows the XRD pattern of the POSS intercalated attapulgite composite material and attapulgite powder in Example 1. Detailed Implementation

[0033] 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.

[0034] The sources of some components in the examples and comparative examples are as follows: Polypropylene chips, model PPH-XR-045, were purchased from Shandong Kairi Chemical Co., Ltd. Cashew phenol, product number C1057201, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Triethylamine, CAS No. 121-44-8, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Fatty acid modified magnesium hydroxide, model KISUMA 5A-C, has a specific surface area of ​​4.4 m². 2 / g, average particle size D 50 The thickness was 0.94 μm, and the drying loss was 0.07%. It was purchased from KESMA (Dandong) High-Tech Materials Technology Co., Ltd. Ordinary magnesium hydroxide powder, item number M104278, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Leyte stone powder was purchased from Hubei Mingliu Technology Co., Ltd. Dicyandiamide, CAS No. 461-58-5, was purchased from Sinopharm Chemical Reagent Co., Ltd. Aminopropylheptyl cage-like polysilsesquioxane, item number 9502028, purchased from Forsman Technology (Beijing) Co., Ltd. Maleic anhydride-grafted polypropylene, model 900P, purchased from Nanjing Feiteng New Material Technology Co., Ltd. Polyethylene wax, product number P903666, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Calcium stearate, CAS No. 1592-23-0, purchased from Sinopharm Chemical Reagent Co., Ltd. Antioxidant 1010 was purchased from Nanjing Hualiming Chemical Co., Ltd. Antioxidant 1098 was purchased from Nanjing Hualiming Chemical Co., Ltd. Antioxidant 168 was purchased from Nanjing Hualiming Chemical Co., Ltd.

[0035] Example 1: This example provides a method for preparing an aging-resistant cable protection tube, including the following steps: S1. By weight, 100 parts of cashew nut shell powder, 40 parts of triethylamine, and 20 parts of cyanuric chloride were added to 200 parts of N,N-dimethylformamide. The mixture was stirred in an ice bath for 4 hours, then heated to 90°C and reacted for 100 minutes. After the reaction was completed, the mixture was cooled to room temperature, filtered to obtain the filtrate, rotary evaporated, washed with water, and dried to obtain modified cashew nut shell powder. 90 parts of polypropylene chips, 20 parts of modified cashew nut shell powder, and 2 parts of dicumyl peroxide were added to a twin-screw extruder and melt-grafted at a temperature of 180°C and a screw speed of 30 r / min. The mixture was washed with acetone and vacuum dried to obtain grafted modified polypropylene.

[0036] S2. 90 parts of grafted modified polypropylene, 30 parts of filler (20 parts of fatty acid modified magnesium hydroxide and 10 parts of POSS intercalated attapulgite composite material), 8 parts of maleic anhydride grafted polypropylene, 2 parts of lubricant polyethylene wax, and 0.6 parts of antioxidant 1010 are mixed to obtain a mixture. The mixture is fed into a twin-screw extruder, and the temperatures of the first zone are set to 175°C, the second zone to 185°C, the third zone to 190°C, the fourth zone to 195°C, and the die head to 200°C. The extrusion, sizing, cooling, and traction are carried out sequentially to obtain an aging-resistant cable protection pipe.

[0037] Preparation of the POSS intercalated attapulgite composite material: 10 parts by weight of dicyandiamide were added to 500 parts by weight of deionized water and sonicated for 40 min. Then, 10 parts by weight of attapulgite powder were added and stirred for 25 min. The mixture was then heated to 70°C and stirred for 10 h. After drying and grinding, a precursor was obtained. The precursor was transferred to a tube furnace and calcined at 550°C for 4 h under an argon atmosphere. After cooling, the precursor was washed with deionized water, filtered, and dried to obtain the attapulgite composite material. 6 parts by weight of aminopropylheptyl cage-like polysilsesquioxane were added to 50 parts by weight of tetrahydrofuran and stirred for 60 min. Then, 12 parts by weight of 10% hydrochloric acid aqueous solution were added dropwise to obtain an intercalation treatment solution. 10 parts by weight of the attapulgite composite material were added to 200 parts by weight of deionized water and stirred for 12 h. Then, the intercalation treatment solution was added and stirred for 24 h. The mixture was filtered, washed with water, and dried under vacuum to obtain the POSS intercalated attapulgite composite material. The POSS intercalated attapulgite composite material and attapulgite powder were characterized, and their FTIR spectra are shown below. Figure 1 As shown, the XRD pattern is as follows Figure 2 As shown.

[0038] Example 2: This example provides a method for preparing an aging-resistant cable protection tube, including the following steps: S1. By weight, 90 parts of cashew nut shell powder, 30 parts of triethylamine, and 18 parts of cyanuric chloride were added to 180 parts of N,N-dimethylformamide. The mixture was stirred in an ice bath for 2 hours, then heated to 80°C and reacted for 120 minutes. After the reaction was completed, the mixture was cooled to room temperature, filtered to obtain the filtrate, rotary evaporated, washed with water, and dried to obtain modified cashew nut shell powder. 80 parts of polypropylene chips, 10 parts of modified cashew nut shell powder, and 1 part of dicumyl peroxide were added to a twin-screw extruder and melt-grafted at a temperature of 170°C and a screw speed of 40 r / min. The mixture was washed with acetone and vacuum dried to obtain grafted modified polypropylene.

[0039] S2. Mix 80 parts of grafted modified polypropylene, 20 parts of filler (10 parts of fatty acid modified magnesium hydroxide and 10 parts of POSS intercalated attapulgite composite material), 6 parts of maleic anhydride grafted polypropylene, 1 part of lubricant calcium stearate, and 0.4 parts of antioxidant 1098 to obtain a mixture. Feed the mixture into a twin-screw extruder and set the temperature of zone 1 to 170°C, zone 2 to 180°C, zone 3 to 185°C, zone 4 to 190°C, and the die head temperature to 195°C. Perform melt plasticization, extrusion, sizing, cooling, and traction in sequence to obtain an aging-resistant cable protection pipe.

[0040] Preparation of the POSS intercalated attapulgite composite material: By weight, 8 parts of dicyandiamide were added to 400 parts of deionized water and sonicated for 30 min, then 8 parts of attapulgite powder were added and stirred for 15 min, then heated to 60℃ and stirred for 12 h, dried, and ground to obtain a precursor. The precursor was transferred to a tube furnace and calcined at 500℃ for 6 h under an argon atmosphere. After cooling, it was washed with deionized water, filtered, and dried to obtain the attapulgite composite material. 4 parts of aminopropylheptyl cage-like polysilsesquioxane were added to 40 parts of tetrahydrofuran and stirred for 50 min, then 10 parts of 10% hydrochloric acid aqueous solution were added dropwise to obtain an intercalation treatment solution. 8 parts of the attapulgite composite material were added to 180 parts of deionized water and stirred for 10 h, then the intercalation treatment solution was added and stirred for 20 h, filtered, washed with water, and vacuum dried to obtain the POSS intercalated attapulgite composite material.

[0041] Example 3: This example provides a method for preparing an aging-resistant cable protection tube, including the following steps: S1. By weight, 95 parts of cashew nut shell powder, 35 parts of triethylamine, and 19 parts of cyanuric chloride were added to 190 parts of N,N-dimethylformamide. The mixture was stirred in an ice bath for 3 hours, then heated to 85°C and reacted for 110 minutes. After the reaction was completed, the mixture was cooled to room temperature, filtered to obtain the filtrate, rotary evaporated, washed with water, and dried to obtain modified cashew nut shell powder. 85 parts of polypropylene chips, 14 parts of modified cashew nut shell powder, and 1.6 parts of dicumyl peroxide were added to a twin-screw extruder and melt-grafted at a temperature of 174°C and a screw speed of 38 r / min. The mixture was washed with acetone and vacuum dried to obtain grafted modified polypropylene.

[0042] S2. Mix 87 parts of grafted modified polypropylene, 25 parts of filler (15 parts of fatty acid modified magnesium hydroxide and 10 parts of POSS intercalated attapulgite composite material), 7 parts of maleic anhydride grafted polypropylene, 1.4 parts of lubricant calcium stearate, and 0.5 parts of antioxidant 168 to obtain a mixture. Feed the mixture into a twin-screw extruder and set the temperature of zone 1 to 173°C, zone 2 to 182°C, zone 3 to 187°C, zone 4 to 194°C, and the die head temperature to 199°C. Perform melt plasticization, extrusion, sizing, cooling, and traction in sequence to obtain an aging-resistant cable protection pipe.

[0043] Preparation of the POSS intercalated attapulgite composite material: By weight, 9 parts of dicyandiamide were added to 450 parts of deionized water and sonicated for 34 min. Then, 9 parts of attapulgite powder were added and stirred for 18 min. The mixture was then heated to 65℃ and stirred for 11 h. After drying and grinding, a precursor was obtained. The precursor was transferred to a tube furnace and calcined at 530℃ for 5 h under an argon atmosphere. After cooling, the precursor was washed with deionized water, filtered, and dried to obtain the attapulgite composite material. 5 parts of aminopropylheptyl cage-like polysilsesquioxane were added to 45 parts of tetrahydrofuran and stirred for 57 min. Then, 11 parts of a 10% hydrochloric acid aqueous solution were added dropwise to obtain an intercalation treatment solution. 9 parts of the attapulgite composite material were added to 190 parts of deionized water and stirred for 11 h. Then, the intercalation treatment solution was added and stirred for 22 h. The mixture was filtered, washed with water, and vacuum dried to obtain the POSS intercalated attapulgite composite material.

[0044] Comparative Example 1 The difference between this comparative example and Example 1 is that polypropylene chips (model PPH-XR-045) were used instead of grafted modified polypropylene.

[0045] Comparative Example 2 The difference between this comparative example and Example 1 is that the filler was changed to 20 parts of ordinary magnesium hydroxide powder (item number M104278) and 10 parts of POSS intercalated rettoite composite material.

[0046] Comparative Example 3 The difference between this comparative example and Example 1 is that the filler was changed to 20 parts of fatty acid-modified magnesium hydroxide and 10 parts of attapulgite powder.

[0047] Comparative Example 4 The difference between this comparative example and Example 1 is that the filler was changed to 30 parts of fatty acid modified magnesium hydroxide.

[0048] Comparative Example 5 The difference between this comparative example and Example 1 is that the filler was changed to 30 parts of POSS intercalated rettoite composite material.

[0049] Performance testing The performance of the above embodiments and comparative examples was tested: (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.

[0050] (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.

[0051] (3) Aging resistance test: The samples of the examples and comparative examples were subjected to heat aging treatment in accordance with the provisions of GB / T 2951.12-2008 General test methods for insulation and sheath materials of cables and optical cables Part 12: General test methods for heat aging test method. They were heat aged at 80°C for 1000h. Then, the impact strength before and after heat aging was tested in accordance with the requirements of GB / T 1843-2008 Determination of impact strength of plastic cantilever beams. The impact strength retention rate was calculated. The higher the impact strength retention rate, the better the aging resistance performance.

[0052] The above performance test data are shown in Table 1;

[0053] .

[0054] As can be seen from the above, the present invention first prepares modified cashew phenol using cashew phenol and melamine as raw materials, mixes the modified cashew phenol with polypropylene chips and performs melt grafting to obtain grafted modified polypropylene, then prepares palatite composite material using palatite powder and dicyandiamide as raw materials, and uses aminopropylheptyl cage-like polysilsesquioxane to perform intercalation treatment on palatite composite material to obtain POSS intercalated palatite composite material, and uses fatty acid modified magnesium hydroxide as a compound filler, and finally combines maleic anhydride grafted polypropylene, lubricant, antioxidant, etc. to perform melt extrusion molding to obtain aging-resistant cable protection pipe (Examples 1 to 3), which has better comprehensive performance.

[0055] Compared to Example 1, the use of polypropylene chips (model PPH-XR-045) instead of grafted modified polypropylene resulted in a lack of grafting effect from triazine-modified cashew phenol, leading to decreased flame retardancy and poorer aging resistance (Comparative Example 1); compared to Example 1, the filler was changed to 20 parts of ordinary magnesium hydroxide powder (item number M104278) and 10 parts of POSS intercalated attapulgite composite material, resulting in a lack of fatty acid-modified magnesium hydroxide, leading to decreased flame retardancy and poorer aging resistance (Comparative Example 2); compared to Example 1, the filler was changed to 20 parts of fatty acid-modified magnesium hydroxide and 10 parts of attapulgite powder, lacking the effect of POSS intercalated attapulgite composite material, resulted in decreased flame retardant performance and worsened aging resistance (Comparative Example 3); Compared with Example 1, the filler was changed to 30 parts of fatty acid modified magnesium hydroxide, but the lack of POSS intercalated attapulgite composite material resulted in poor performance, resulting in decreased flame retardant performance and worsened aging resistance (Comparative Example 4); Compared with Example 1, the filler was changed to 30 parts of POSS intercalated attapulgite composite material, but the lack of fatty acid modified magnesium hydroxide resulted in poor performance, resulting in decreased flame retardant performance and worsened aging resistance (Comparative Example 5).

Claims

1. A method for preparing an aging-resistant cable protection pipe, characterized in that, Includes the following steps: S1. First, modified cashew phenol is prepared using cashew phenol and melamine chloride as raw materials. Then, the modified cashew phenol and polypropylene chips are mixed and melt-grafted to obtain grafted modified polypropylene. S2. Graft-modified polypropylene, filler, maleic anhydride-grafted polypropylene, lubricant, and antioxidant are mixed to obtain a mixture. The mixture is fed into a twin-screw extruder and subjected to melt plasticization, extrusion, sizing, cooling, and traction in sequence to obtain an aging-resistant cable protection pipe. The preparation steps of the modified cashew nut phenol are as follows: by weight, 90-100 parts of cashew nut phenol, 30-40 parts of triethylamine and 18-20 parts of cyanuric chloride are added to 180-200 parts of N,N-dimethylformamide, stirred in an ice bath for 2-4 hours, then heated to 80-90℃ and reacted for 100-120 minutes. After the reaction is completed, the mixture is cooled to room temperature, filtered to obtain the filtrate, rotary evaporated, washed with water and dried to obtain the modified cashew nut phenol. The melt grafting step is as follows: by weight, 80-90 parts of polypropylene chips, 10-20 parts of modified cashew nut shell powder and 1-2 parts of dicumyl peroxide are added to a twin-screw extruder, and melt grafting is carried out at a temperature of 170-180℃ and a screw speed of 30-40 r / min. The product is then washed with acetone and vacuum dried to obtain grafted modified polypropylene. The filler is a composite material of fatty acid modified magnesium hydroxide and POSS intercalated attapulgite; the mass ratio of fatty acid modified magnesium hydroxide and POSS intercalated attapulgite composite material in the filler is (1~2):1; The preparation method of the POSS intercalated attapulgite composite material is as follows: first, attapulgite powder and dicyandiamide are used as raw materials to prepare attapulgite composite material, and then aminopropylheptyl cage-like polysilsesquioxane is used to intercalate the attapulgite composite material to obtain the POSS intercalated attapulgite composite material.

2. The method for preparing an aging-resistant cable protection pipe according to claim 1, characterized in that, The components in step S2, by weight, include: 80-90 parts of grafted modified polypropylene, 20-30 parts of filler, 6-8 parts of maleic anhydride grafted polypropylene, 1-2 parts of lubricant, and 0.4-0.6 parts of antioxidant.

3. The method for preparing an aging-resistant cable protection pipe according to claim 1, characterized in that, The specific surface area of ​​the fatty acid-modified magnesium hydroxide is 2~5m². 2 / g, with an average particle size D50 of 0.5~1.0μm and a drying loss of 0.05~0.10%.

4. The method for preparing an aging-resistant cable protection pipe according to claim 1, characterized in that, The preparation steps of the attapulgite composite material are as follows: by weight, 8-10 parts of dicyandiamide are added to 400-500 parts of deionized water and ultrasonicated for 30-40 minutes, then 8-10 parts of attapulgite powder are added and stirred for 15-25 minutes, then heated to 60-70℃ and stirred for 10-12 hours, dried, ground, and a precursor is obtained. The precursor is transferred to a tube furnace and calcined at 500-550℃ for 4-6 hours under an argon atmosphere. After cooling, it is washed with deionized water, filtered, and dried to obtain the attapulgite composite material.

5. The method for preparing an aging-resistant cable protection pipe according to claim 1, characterized in that, The intercalation treatment steps are as follows: by weight, 4-6 parts of aminopropylheptyl cage-like polysilsesquioxane are added to 40-50 parts of tetrahydrofuran and stirred for 50-60 minutes. Then, 10-12 parts of 10% hydrochloric acid aqueous solution are added dropwise to obtain the intercalation treatment solution. 8-10 parts of attapulgite composite material are added to 180-200 parts of deionized water and stirred for 10-12 hours. Then, the intercalation treatment solution is added and stirred for 20-24 hours. The mixture is then filtered, washed with water, and vacuum dried to obtain the POSS intercalated attapulgite composite material.

6. An aging-resistant cable protection pipe, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 5.

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