Toughened and reinforced modified PVC (polyvinyl chloride) material for electric power protection tube and preparation method thereof

Abstract

The invention discloses a toughened and reinforced modified PVC (polyvinyl chloride) material for an electric power protection tube and a preparation method thereof, belongs to the technical field of preparation of PVC materials, and aims to solve the technical problem that the strength, toughness, heat resistance and aging resistance of a PVC material in the prior art need to be further improved. The composite material specifically comprises the following components in parts by weight: 50-70 parts of PVC, 1-2 parts of dicumyl peroxide, 2-4 parts of maleic anhydride, 8-12 parts of a thermoplastic elastomer, 4-8 parts of a toughening agent, 3-5 parts of a stabilizer compound, 10-15 parts of a glass fiber reinforcing agent and 3-5 parts of an auxiliary additive. The thermoplastic elastomer, the flexibilizer, the stabilizer compound and the glass fiber reinforcing agent are added into the PVC material, so that the tensile strength, bending strength, cantilever notched impact strength, elongation at break, heat resistance and aging resistance of the PVC material are further improved.

Description

Technical Field

[0001] This invention relates to the field of PVC material preparation technology, specifically to toughened and reinforced modified PVC materials for power protection pipes and their preparation methods. Background Technology

[0002] PVC material is widely used in the field of power protection pipes due to its electrical insulation, corrosion resistance and economical processing. It can protect cables from mechanical damage. However, traditional PVC material has performance bottlenecks when used in power protection pipes. It is prone to cracking and deformation when buried or subjected to mechanical loads. Its strength and toughness need to be further improved. It is also prone to heat deformation at high temperatures and has limited heat resistance. In addition, cables used outdoors for a long time are easily degraded by photo-oxidation, which greatly shortens their service life.

[0003] Traditional PVC modification techniques, while developing, have limitations. In toughening and strengthening modifications, elastomer blending improves toughness but affects strength, while inorganic fillers enhance rigidity but increase material brittleness. In heat-resistant modifications, chlorination is costly and releases harmful gases during processing, while cross-linking modification easily increases material brittleness and involves complex processes. When modifying aging resistance, the effect of aging agents weakens with long-term use. These issues cannot be addressed by a single modification to achieve a comprehensive performance improvement.

[0004] Given that current single modification methods are difficult to synergistically improve multiple properties of PVC, and multi-component composite modification faces problems such as interface issues, this invention proposes a multi-component synergistic modification strategy for the needs of power protection pipes. It achieves synergistic strength and toughness through thermoplastic elastomers and nano-silica toughening agents, improves heat resistance by using stabilizer complexes and glass fiber reinforcing agents, and constructs an aging-resistant protection system with the help of antioxidants, breaking through the bottlenecks of traditional modification and providing a new path for the preparation of PVC materials for power protection pipes. Summary of the Invention

[0005] The purpose of this invention is to provide toughened and reinforced modified PVC material for power protection pipes and its preparation method, in order to solve the technical problem that the strength, toughness, heat resistance and aging resistance of PVC materials in the prior art need to be further improved.

[0006] The objective of this invention can be achieved through the following technical solution: a toughened and reinforced modified PVC material for power protection pipes, comprising the following components by weight: 50-70 parts PVC, 2-4 parts maleic anhydride, 1-2 parts dicumyl peroxide, 8-12 parts thermoplastic elastomer, 4-8 parts toughening agent, 3-5 parts stabilizer complex, 10-15 parts glass fiber reinforcing agent, and 3-5 parts auxiliary additives; The auxiliary additives comprise the following components by weight: 1-2 parts SW-101, 1-2 parts LUB-501 and 0.5-1 parts antioxidant 1010.

[0007] Furthermore, the preparation method of the thermoplastic elastomer is as follows: dry hydroxyl-terminated polycaprolactone and isoflurane diisocyanate are added to a polytetrafluoroethylene reactor, a catalyst is added, the system is stirred at 70-80℃ under a nitrogen atmosphere for 1 hour, then a chain extender is added, the temperature is raised to 90-100℃ and stirred for another 30 minutes, and the thermoplastic elastomer is obtained after post-treatment.

[0008] Reaction principle:

[0009] In the formula:

[0010] Dry hydroxyl-terminated polycaprolactone (-OH) and isoflurane diisocyanate (-NCO) undergo a polyurethane prepolymerization reaction at 70-80℃ under a nitrogen atmosphere and with the aid of a catalyst. The -NCO and -OH gradually add to form a prepolymer containing terminal -NCO. After adding chain extender isocyanate and reacting with the chain extender, the temperature is raised to 90-100℃. The terminal -NCO of the prepolymer undergoes a urethane chain extension reaction with the -NH2 of the chain extender. The -NCO and -NH2 add to form urea bonds -NH-CO-NH-, which rapidly increases the molecular chain length and crosslinking points, constructing a complete thermoplastic elastomer structure with alternating "soft segment-hard segment".

[0011] Furthermore, the catalyst is stannous octoate, the chain extender is dimethylthiotoluene diamine, the ratio of the hydroxyl-terminated polycaprolactone, catalyst and chain extender is 8-10g:0.01-0.02g:1-2g, the amount of isoflurane diisocyanate added is 0.55 times the total molar amount of hydroxyl groups in the hydroxyl-terminated polycaprolactone, and the post-treatment includes: after the reaction is completed, pouring the viscous liquid obtained from the reaction into a mold while it is still hot to form it, and demolding it after it cools down.

[0012] Furthermore, the toughening agent is prepared by adding nano-silica, an aqueous ethanol solution, methyl 3-[(2-hydroxyethyl)amino]propionate and a catalyst into a reaction vessel, reacting at 120-150℃ for 4-6 hours, and then performing post-treatment to obtain the toughening agent.

[0013] Reaction principle: Under the catalysis of p-toluenesulfonic acid, the silanol groups on the surface of nano-silica are first protonated, enhancing the electrophilicity of silicon atoms. At this time, the hydroxyl group of the hydroxyethyl group in methyl 3-[(2-hydroxyethyl)amino]propionate acts as a nucleophile, carrying a lone pair of electrons to attack the silicon atom of the protonated silanol group. Subsequently, the OH bond of the silanol group breaks, removing one molecule of water and forming a silicon-oxygen bond to graft organic molecules onto the surface of silica, thus obtaining a toughening agent.

[0014] Furthermore, the catalyst is p-toluenesulfonic acid, and the ratio of nano-silica, ethanol aqueous solution, methyl 3-[(2-hydroxyethyl)amino]propionate and catalyst is 1-2g:20-30mL:3-5g:0.1-0.2g. The ethanol aqueous solution has a mass fraction of 10%. The post-treatment includes: after the reaction is completed, the product is placed in a filter centrifuge for 15min, the solid product is washed three times with deionized water, filtered, and the product is placed in a vacuum drying oven and dried at 60℃ and 2kPa vacuum for 12h.

[0015] Furthermore, the stabilizer complex is prepared by dissolving chlorinated polyvinyl chloride in cyclohexanone, raising the temperature to 60-80°C, adding methyl methacrylate and azobisisobutyronitrile, reacting for 6-8 hours, and then performing post-treatment to obtain the stabilizer complex.

[0016] Reaction principle: When chlorinated polyvinyl chloride is dissolved in cyclohexanone and heated to 60-80℃, azobisisobutyronitrile decomposes to generate free radicals. On the one hand, this initiates the free radical polymerization of methyl methacrylate, and on the other hand, it generates active free radical sites on the chlorinated polyvinyl chloride molecular chain, which in turn initiates the graft polymerization of methyl methacrylate on its chain to form a stabilizer complex.

[0017] Furthermore, the ratio of chlorinated polyvinyl chloride, cyclohexanone, methyl methacrylate, and azobisisobutyronitrile is 10-12g:50-60mL:2-3mL:1-2g. The post-treatment includes: stopping heating after the reaction is completed, waiting for the reaction system temperature to drop to room temperature, adding 3 times the volume of methanol, stirring until a white flocculent precipitate appears, letting it stand for 30 minutes, filtering the product, and then placing the solid product in a vacuum drying oven and drying it at 60℃ and 2kPa vacuum for 12 hours.

[0018] Furthermore, the glass fiber reinforcing agent is prepared by the following steps: A1. Slowly add hydrogen peroxide aqueous solution to glass fiber, add 0.5 mol / L sulfuric acid solution dropwise, adjust pH to 4-5, heat to reflux, filter, wash with deionized water 3-5 times, and dry to obtain pretreated glass fiber; A2. Polyacrylic acid, aqueous ethanol solution, propyltriethoxysilane isocyanate and dibutyltin dilaurate are added to a reaction vessel and reacted at 60-80℃ under nitrogen atmosphere for 4-6 hours. The modified polyacrylic acid is then obtained after post-treatment. A3. Add modified polyacrylic acid and tetrahydrofuran to the reactor and stir. Raise the reactor temperature to 50-60℃ and stir until the system is dissolved. Add pretreated glass fiber to the reactor and stir to disperse for 30-50 minutes. Add catalyst to the reactor and keep it at the temperature for 60-80 minutes. Post-treatment yields glass fiber reinforcement.

[0019] Reaction principle: First, the surface of glass fiber is oxidized and etched using an aqueous solution of hydrogen peroxide under acidic conditions to generate a large number of polar groups such as silanol groups. Then, using dibutyltin dilaurate as a catalyst, propyltriethoxysilane isocyanate undergoes an addition reaction with polyacrylic acid to generate urethane bonds. Simultaneously, the silane ethoxy groups hydrolyze and condense to form siloxane segments, thus obtaining modified polyacrylic acid. Finally, the modified polyacrylic acid is dissolved in tetrahydrofuran, and the silanol groups in the modified polyacrylic acid condense with the silanol groups on the surface of the pretreated glass fiber under the action of a catalyst. The modified polyacrylic acid is then grafted onto the surface of the glass fiber through Si-O-Si covalent bonds to obtain a glass fiber reinforcing agent.

[0020] Further, in step A1, the ratio of glass fiber to hydrogen peroxide aqueous solution is 1-3g:20-30mL, and the mass fraction of hydrogen peroxide in the hydrogen peroxide aqueous solution is 30%; in step A2, the ratio of polyacrylic acid, toluene, and dibutyltin dilaurate is 1-2mL:10-20mL:0.05-0.1g, the amount of propyltriethoxysilane added is 1.05 times the total molar amount of carboxyl groups in the polyacrylic acid, and the mass fraction of ethanol in the ethanol aqueous solution is 90%. The post-treatment includes: after the reaction is completed, the air in the reaction vessel is extracted using a vacuum pump, and distillation is carried out at 80°C. After distillation, heating is stopped and the pressure is slowly restored to atmospheric pressure. In step A3, the ratio of modified polyacrylic acid, tetrahydrofuran, pretreated glass fiber and catalyst is 4-6g:20-30mL:2-3g:0.1-0.2g. The catalyst is p-toluenesulfonic acid. The post-treatment includes: after the reaction is completed, filtration is performed, the filter residue is washed three times with deionized water, and the product is placed in a vacuum drying oven and dried at 60°C for 12 hours.

[0021] This invention also proposes a method for preparing toughened and reinforced modified PVC material for power protection pipes. PVC, dicumyl peroxide, and maleic anhydride are added to a mixer and mixed for 5-10 minutes under a nitrogen atmosphere at 180-220°C. Then, a thermoplastic elastomer is added, and after the two are melt-mixed, a toughening agent, a stabilizer complex, a glass fiber reinforcing agent, and auxiliary additives are added and mixed for 10-15 minutes. The material is then discharged to obtain the modified PVC material.

[0022] The present invention has the following beneficial effects: 1. The thermoplastic elastomer of the present invention, after prepolymerization and chain extension of hydroxyl-terminated polycaprolactone and isoflurane diisocyanate, forms an alternating structure of "soft segment-hard segment". The urea bonds in the hard segment enhance the interfacial bonding force with the PVC matrix through hydrogen bonds, while the polycaprolactone segments in the soft segment endow the material with deformation capability. In the toughening agent, nano-silica is grafted with methyl 3-[(2-hydroxyethyl)amino]propionate by p-toluenesulfonic acid catalysis to form an "inorganic nanoparticle-organic polyether chain" network. During dispersion, the impact energy is dissipated through the support of rigid particles and the energy absorption of flexible chain segments. In the glass fiber reinforcing agent, the surface of the glass fiber is etched with hydrogen peroxide aqueous solution to generate silanol groups, and then grafted with modified polyacrylic acid to form a Si-O-Si covalent rigid skeleton. The three work together to improve the tensile strength and flexural strength of the PVC material, as well as the notched impact strength and elongation at break of the cantilever beam, achieving simultaneous optimization of strength and toughness.

[0023] 2. The stabilizer complex of the present invention is formed by graft polymerization of chlorinated polyvinyl chloride and methyl methacrylate initiated by azobisisobutyronitrile. In the network formed, the rigid chlorinated polyvinyl chloride segments increase the heat distortion temperature and inhibit the thermal motion of molecular chains, while the flexible polymethyl methacrylate segments reduce the viscosity of the processed melt. The hard segment structure of the thermoplastic elastomer inhibits molecular chain slippage at high temperature and reduces heat deformation. After heat aging, it has little effect on the tensile strength, flexural strength, cantilever beam impact strength and elongation at break of the material, effectively improving the heat resistance and thermal stability of PVC material during long-term use.

[0024] 3. The graft copolymer structure of the stabilizer complex of the present invention has a shielding effect on ultraviolet light, reducing the photo-oxidative breakage of PVC molecular chains; the antioxidant 1010 in the auxiliary additives can capture free radicals generated by photo-oxidation, and SW-101 and LUB-501 improve interfacial compatibility and flowability, reducing stress concentration during aging; the siloxane layer on the glass fiber surface of the glass fiber reinforcement forms a physical barrier, blocking water and oxygen erosion and enhancing interfacial stability. After ultraviolet aging, the effect on the tensile strength, flexural strength, cantilever beam impact strength and elongation at break of the material is small, showing that the PVC material has better ultraviolet aging resistance and extending the outdoor service life of the power protection pipe. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In this invention, the PVC is selected from Shanghai Zhaohe Plastics Co., Ltd., with CAS number 9002-86-2 and grade TG-1300; In this invention, the chlorinated polyvinyl chloride is selected from Dongguan Yingxiang Plastic Raw Materials Co., Ltd., model HI-805, specification 25mm, and active ingredient content 100%; In this invention, the hydroxyl-terminated polycaprolactone is selected from Shaanxi Xingbei Aike Biotechnology Co., Ltd. Product name: HO-PCL-OH, purity: 95%, model: xb-16; In this invention, the nano-silica is selected from Qinghe County Chaotai Metal Materials Co., Ltd., with CAS number 1399-2-3, particle size of 500 mesh, grade SF93, and silicon content ≥99.9%; In this invention, the glass fiber is selected from Taian Haosong Fiber Co., Ltd., with a compressive strength of 1800MPa, a model of bb-7, and a length of 4.5mm; In this invention, the polyacrylic acid is selected from Shandong Xinghai Chemical Co., Ltd., with CAS number 9003-01-4, an effective ingredient content of 30%, and a molecular weight of 10000.

[0027] Example 1 This embodiment provides a method for preparing toughened and reinforced modified PVC material for power protection pipes, including the following steps: S1. Preparation of thermoplastic elastomers Hydroxyl-terminated polycaprolactone was added to a nitrogen-circulating drying oven and dried at 50°C for 12 hours to obtain dried hydroxyl-terminated polycaprolactone. Weigh out 800g of dried hydroxyl-terminated polycaprolactone, calculate the amount of isoflurane diisocyanate to be added based on 0.55 times the total molar amount of hydroxyl groups in the hydroxyl-terminated polycaprolactone, and add them together to a polytetrafluoroethylene reactor. Add 1g of stannous octoate and stir the system at 70°C under a nitrogen atmosphere for 1 hour. Then add 100g of dimethylthiotoluene diamine, raise the temperature to 90°C and stir for another 30 minutes. After the reaction is complete, pour the viscous liquid obtained from the reaction into a mold while it is still hot to form it. After it cools, demold it to obtain a thermoplastic elastomer.

[0028] S2, Preparation of toughening agent Weigh out 10g of nano silica, 200mL of 10% ethanol aqueous solution, 30g of methyl 3-[(2-hydroxyethyl)amino]propionate and 1g of p-toluenesulfonic acid and add them to the reaction vessel. React at 120℃ for 4h. After the reaction is completed, put the product into a filter centrifuge for 15min to separate it. Then wash the solid product with deionized water 3 times, filter it, and put the product into a vacuum drying oven to dry it at 60℃ and 2kPa vacuum for 12h to obtain the toughening agent.

[0029] S3. Preparation of stabilizer complex Weigh out 100g of chlorinated polyvinyl chloride and dissolve it in 500mL of cyclohexanone. Heat the solution to 60℃, add 20mL of methyl methacrylate and 10g of azobisisobutyronitrile, and react for 6h. After the reaction is complete, stop heating and wait for the temperature of the reaction system to drop to room temperature. Add 3 times the volume of methanol and stir until a white flocculent precipitate appears. After standing for 30min, filter the product. Place the solid product in a vacuum drying oven and dry it at 60℃ and 2kPa vacuum for 12h to obtain the stabilizer complex.

[0030] S4. Preparation of glass fiber reinforcing agent Weigh out 200 mL of 10% hydrogen peroxide aqueous solution and slowly add it to 10 g of glass fiber. Add 0.5 mol / L sulfuric acid solution dropwise to adjust the pH to 4. Heat and reflux, filter, wash three times with deionized water, and dry to obtain pretreated glass fiber. Weigh out 100 mL of polyacrylic acid, 1 L of ethanol aqueous solution with a mass fraction of 90% and 5 g of dibutyltin dilaurate. Calculate the amount of propyltriethoxysilane to be added based on 1.05 times the total molar amount of carboxyl groups in the polyacrylic acid. Add all of these to the reaction vessel and react at 60 °C under nitrogen atmosphere for 4 h. After the reaction is complete, use a vacuum pump to remove the air from the reaction vessel and distill at 80 °C. After distillation is complete, stop heating and slowly restore to atmospheric pressure to obtain modified polyacrylic acid. Weigh 40g of modified polyacrylic acid and 200mL of tetrahydrofuran and add them to the reactor. Stir the reactor and raise the temperature to 50℃. Stir until the system is dissolved. Add 20g of pretreated glass fiber to the reactor and stir to disperse for 30min. Add 1g of p-toluenesulfonic acid to the reactor and keep it at the temperature for 60min. After the reaction is complete, filter the mixture and wash the filter residue three times with deionized water. Place the product in a vacuum drying oven and dry it at 60℃ for 12h to obtain the glass fiber reinforcing agent.

[0031] S5. Preparation of modified PVC materials Weigh out 1 part SW-101, 1 part LUB-501 and 0.5 parts antioxidant 1010 by weight, mix them evenly to form an auxiliary additive; Weigh out 50 parts PVC, 1 part dicumyl peroxide and 2 parts maleic anhydride by weight and add them to a mixer. Mix for 5 minutes at 180°C under a nitrogen atmosphere. Then add 8 parts thermoplastic elastomer. After the two are melt-mixed, add 4 parts toughening agent, 3 parts stabilizer complex, 10 parts glass fiber reinforcing agent and 3 parts auxiliary additives. Mix for 10 minutes and discharge to obtain modified PVC material.

[0032] Example 2 This embodiment provides a method for preparing toughened and reinforced modified PVC material for power protection pipes, including the following steps: S1. Preparation of thermoplastic elastomers Hydroxyl-terminated polycaprolactone was added to a nitrogen-circulating drying oven and dried at 50°C for 12 hours to obtain dried hydroxyl-terminated polycaprolactone. Weigh out 900g of dried hydroxyl-terminated polycaprolactone. Calculate the amount of isoflurane diisocyanate to be added based on 0.55 times the total molar amount of hydroxyl groups in the hydroxyl-terminated polycaprolactone. Add the mixture to a polytetrafluoroethylene reactor. Add 2g of stannous octoate. Stir the system at 75°C under a nitrogen atmosphere for 1 hour. Then add 200g of dimethylthiotoluene diamine. Raise the temperature to 95°C and stir for another 30 minutes. After the reaction is complete, pour the viscous liquid obtained from the reaction into a mold while it is still hot. After cooling, demold to obtain a thermoplastic elastomer.

[0033] S2, Preparation of toughening agent Weigh out 15g of nano silica, 250mL of 10% ethanol aqueous solution, 40g of methyl 3-[(2-hydroxyethyl)amino]propionate and 1g of p-toluenesulfonic acid and add them to a reaction vessel. React at 130℃ for 5h. After the reaction is complete, put the product into a filter centrifuge for 15min, wash the solid product three times with deionized water, filter it, and put the product into a vacuum drying oven and dry it at 60℃ and 2kPa vacuum for 12h to obtain the toughening agent.

[0034] S3. Preparation of stabilizer complex Weigh out 110g of chlorinated polyvinyl chloride and dissolve it in 550mL of cyclohexanone. Heat the solution to 70℃, add 25mL of methyl methacrylate and 15g of azobisisobutyronitrile, and react for 7h. After the reaction is complete, stop heating and wait for the temperature of the reaction system to drop to room temperature. Add 3 times the volume of methanol and stir until a white flocculent precipitate appears. After standing for 30min, filter the product. Place the solid product in a vacuum drying oven and dry it at 60℃ and 2kPa vacuum for 12h to obtain the stabilizer complex.

[0035] S4. Preparation of glass fiber reinforcing agent Weigh out 250 mL of 10% hydrogen peroxide aqueous solution and slowly add it to 20 g of glass fiber. Add 0.5 mol / L sulfuric acid solution dropwise to adjust the pH. Heat and reflux, filter, wash with deionized water 4 times, and dry to obtain pretreated glass fiber. Weigh out 150 mL of polyacrylic acid, 1.5 L of ethanol aqueous solution with a mass fraction of 90%, and 8 g of dibutyltin dilaurate. Calculate the amount of propyltriethoxysilane to be added based on 1.05 times the total molar amount of carboxyl groups in the polyacrylic acid. Add all of these to the reaction vessel and react at 70 °C under nitrogen atmosphere for 5 h. After the reaction is complete, use a vacuum pump to remove the air from the reaction vessel and distill at 80 °C. After distillation, stop heating and slowly restore to atmospheric pressure to obtain modified polyacrylic acid. Weigh out 50g of modified polyacrylic acid and 250mL of tetrahydrofuran and add them to the reactor. Stir the reactor and raise the temperature to 55℃. Stir until the system is dissolved. Add 25g of pretreated glass fiber to the reactor and stir to disperse for 40min. Add 2g of p-toluenesulfonic acid to the reactor and keep it at the temperature for 70min. After the reaction is complete, filter the mixture and wash the filter residue three times with deionized water. Place the product in a vacuum drying oven and dry it at 60℃ for 12h to obtain the glass fiber reinforcing agent.

[0036] S5. Preparation of modified PVC materials Weigh out 2 parts SW-101, 2 parts LUB-501 and 1 part antioxidant 1010 by weight and mix them evenly to form an auxiliary additive. Weigh out 60 parts PVC, 2 parts dicumyl peroxide and 3 parts maleic anhydride by weight and add them to a mixer. Mix for 8 minutes under a nitrogen atmosphere at 200°C. Then add 10 parts thermoplastic elastomer. After the two are melt-mixed, add 6 parts toughening agent, 4 parts stabilizer complex, 12 parts glass fiber reinforcing agent and 4 parts auxiliary additives. Mix for 12 minutes and discharge to obtain modified PVC material.

[0037] Example 3 This embodiment provides a method for preparing toughened and reinforced modified PVC material for power protection pipes, including the following steps: S1. Preparation of thermoplastic elastomers Hydroxyl-terminated polycaprolactone was added to a nitrogen-circulating drying oven and dried at 50°C for 12 hours to obtain dried hydroxyl-terminated polycaprolactone. Weigh 1000g of dried hydroxyl-terminated polycaprolactone, calculate the amount of isoflurane diisocyanate to be added based on 0.55 times the total molar amount of hydroxyl groups in the hydroxyl-terminated polycaprolactone, and add them together to a polytetrafluoroethylene reactor. Add 2g of stannous octoate and stir the system at 80℃ under a nitrogen atmosphere for 1h. Then add 200g of dimethylthiotoluene diamine, raise the temperature to 100℃ and stir for another 30min. After the reaction is complete, pour the viscous liquid obtained from the reaction into a mold while it is still hot to form it. After it cools, demold it to obtain a thermoplastic elastomer.

[0038] S2, Preparation of toughening agent Weigh out 20g of nano-silica, 300mL of 10% ethanol aqueous solution, 50g of methyl 3-[(2-hydroxyethyl)amino]propionate and 2g of p-toluenesulfonic acid and add them to the reaction vessel. React at 150℃ for 6h. After the reaction is completed, put the product into a filter centrifuge for 15min, then wash the solid product three times with deionized water, filter it, and put the product into a vacuum drying oven and dry it at 60℃ and 2kPa vacuum for 12h to obtain the toughening agent.

[0039] S3. Preparation of stabilizer complex Weigh out 120g of chlorinated polyvinyl chloride and dissolve it in 600mL of cyclohexanone. Heat the solution to 80℃, add 30mL of methyl methacrylate and 20g of azobisisobutyronitrile, and react for 8h. After the reaction is complete, stop heating and wait for the temperature of the reaction system to drop to room temperature. Add 3 times the volume of methanol and stir until a white flocculent precipitate appears. After standing for 30min, filter the product. Place the solid product in a vacuum drying oven and dry it at 60℃ and 2kPa vacuum for 12h to obtain the stabilizer complex.

[0040] S4. Preparation of glass fiber reinforcing agent Weigh out 300 mL of 10% hydrogen peroxide aqueous solution and slowly add it to 30 g of glass fiber. Add 0.5 mol / L sulfuric acid solution dropwise to adjust the pH to 5. Heat and reflux, filter, wash with deionized water 5 times, and dry to obtain pretreated glass fiber. Weigh out 200 mL of polyacrylic acid, 2 L of ethanol aqueous solution with a mass fraction of 90% and 10 g of dibutyltin dilaurate. Calculate the amount of propyltriethoxysilane to be added based on 1.05 times the total molar amount of carboxyl groups in the polyacrylic acid. Add all of these to the reaction vessel and react at 80 °C under nitrogen atmosphere for 6 h. After the reaction is complete, use a vacuum pump to remove the air from the reaction vessel and distill at 80 °C. After distillation, stop heating and slowly restore to atmospheric pressure to obtain modified polyacrylic acid. Weigh 60g of modified polyacrylic acid and 300mL of tetrahydrofuran and add them to the reactor. Stir the reactor and raise the temperature to 60℃. Stir until the system is dissolved. Add 30g of pretreated glass fiber to the reactor and stir to disperse for 50min. Add 2g of p-toluenesulfonic acid to the reactor and keep it at the temperature for 80min. After the reaction is complete, filter the mixture and wash the filter residue three times with deionized water. Place the product in a vacuum drying oven and dry it at 60℃ for 12h to obtain the glass fiber reinforcing agent.

[0041] S5. Preparation of modified PVC materials Weigh out 2 parts SW-101, 2 parts LUB-501 and 1 part antioxidant 1010 by weight and mix them evenly to form an auxiliary additive. Weigh out 70 parts PVC, 2 parts dicumyl peroxide and 4 parts maleic anhydride by weight and add them to a mixer. Mix for 10 minutes under a nitrogen atmosphere at 220°C. Then add 12 parts thermoplastic elastomer. After the two are melt-mixed, add 8 parts toughening agent, 5 parts stabilizer complex, 15 parts glass fiber reinforcing agent and 5 parts auxiliary additives. Mix for 15 minutes and discharge to obtain modified PVC material.

[0042] Comparative Example 1 The difference between this comparative example and Example 2 is that step S1 is omitted and thermoplastic elastomer is not added in S5.

[0043] Comparative Example 2 The difference between this comparative example and Example 2 is that step S2 is omitted and no toughening agent is added in S5.

[0044] Comparative Example 3 The difference between this comparative example and Example 2 is that step S3 is omitted and the stabilizer complex is not added in S5.

[0045] Comparative Example 4 The difference between this comparative example and Example 2 is that step S4 is omitted and glass fiber reinforcing agent is not added in S5.

[0046] Performance testing: The unnotched impact strength of the cantilever beams made of toughened and reinforced modified PVC materials for power protection pipes prepared in Examples 1-3 and Comparative Examples 1-4 was determined in accordance with the standard GB / T 1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams". The tensile fracture strain and tensile strength of the toughened and reinforced PVC materials for power protection pipes prepared in Examples 1-3 and Comparative Examples 1-4 were determined in accordance with the standard GB / T 1040.1-2018 "Determination of tensile properties of plastics - Part 1: General". The bending strength of the toughened and reinforced PVC materials for power protection pipes prepared in Examples 1-3 and Comparative Examples 1-4 was determined according to the standard GB / T 9341-2008 "Determination of bending properties of plastics". The specific test results are shown in Table 1-3 below. Table 1 - Performance Test Data of Samples

[0047] The unnotched impact strength, elongation at break, tensile strength, and flexural strength of the toughened and reinforced PVC materials for power protection pipes prepared in Examples 1-3 and Comparative Examples 1-4 were determined according to the standard GB / T 7141-2008 "Test Method for Thermal Aging of Plastics". After thermal aging at 90℃ for 100h, the toughened and reinforced PVC materials for power protection pipes prepared in Examples 1-3 and Comparative Examples 1-4 were determined. Table 2 - Performance Test Data of Samples

[0048] Referring to standard GB / T 16422.3-2022 "Laboratory Light Source Exposure Test Methods for Plastics - Part 3: Fluorescent Ultraviolet Lamps", the toughened and reinforced modified PVC materials for power protection tubes prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to cyclic exposure tests using a combination lamp assembled with four types of ultraviolet lamps. The unnotched impact strength, elongation at break, tensile strength, and flexural strength of the cantilever beam after ultraviolet aging were measured. Table 3 - Performance Test Data of Samples

[0049] Data Analysis: Comparative analysis of the data in Table 1 shows that the toughened and reinforced PVC material for power protection pipes prepared by this invention exhibits an alternating "soft-hard segment" structure in the thermoplastic elastomer. The hard segment urea bonds enhance the interfacial bonding with the PVC matrix through hydrogen bonds, while the soft segment polycaprolactone segments impart deformation capability. The toughening agent, with nano-silica grafted organic polyether chains, forms an "inorganic-organic" network, dissipating impact energy through the synergistic energy dissipation of rigid particles and flexible segments. The glass fiber reinforcing agent, with glass fiber surface grafted with modified polyacrylic acid, constructs a rigid framework through Si-O-Si covalent bonds. The synergistic effect of these three components results in a tensile strength of 67 MPa and a flexural strength of 54 MPa in Example 2, representing increases of 24.1% and 22.7% respectively compared to Comparative Example 1 without thermoplastic elastomer, and increases of 28.8% and 28.6% respectively compared to Comparative Example 2 without toughening agent. The unnotched impact strength of the cantilever beam is 28.8 kJ / m², and the elongation at break is 132%, representing increases of 16.6% respectively compared to Comparative Example 2. And 16.8%, achieving simultaneous optimization of strength and toughness; Comparative analysis of the data in Table 2 shows that the toughened and reinforced PVC material for power protection pipes prepared by this invention, after heat aging, forms a network through graft polymerization of the stabilizer complex. The rigid chlorinated polyvinyl chloride segments increase the heat distortion temperature and inhibit molecular chain thermal motion, while the flexible polymethyl methacrylate segments reduce the viscosity of the processed melt. The thermoplastic elastomer hard segments inhibit molecular chain slippage at high temperatures, reducing heat deformation. After heat aging, Example 2 exhibits a tensile strength of 58 MPa and a flexural strength of 47 MPa, representing increases of 31.8% and 30.6% respectively compared to Comparative Example 3 without the stabilizer complex. The unnotched impact strength of the cantilever beam is 26.7 kJ / m², and the elongation at break is 122%, representing increases of 39.1% and 40.2% respectively compared to Comparative Example 3. This effectively reduces the impact of heat aging on material properties and demonstrates excellent thermal stability. Comparative analysis of the data in Table 3 shows that the toughened and reinforced PVC material for power protection pipes prepared by this invention, after UV aging, exhibits a stabilizer complex graft copolymer structure that shields against UV light, reducing photo-oxidative breakage of PVC molecular chains. In the auxiliary additives, antioxidant 1010 captures photo-oxidative free radicals, while SW-101 and LUB-501 improve interfacial compatibility and flowability, reducing aging stress concentration. The glass fiber reinforcing agent forms a physical barrier on the surface of the glass fiber with a siloxane layer, blocking water and oxygen erosion. After UV aging, Example 2 exhibits a tensile strength of 60 MPa and a flexural strength of 48 MPa, representing increases of 46.3% and 45.5% respectively compared to Comparative Example 1 without added antioxidants. The unnotched impact strength of the cantilever beam is 27.1 kJ / m², and the elongation at break is 124%, representing increases of 62.3% and 61.0% respectively compared to Comparative Example 1, significantly improving the material's UV aging resistance and extending its outdoor service life.

[0050] 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 specific implementations. 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. Toughened and reinforced modified PVC material for power protection pipes, characterized by that, The auxiliary additive comprises the following components by weight: 1-2 parts of SW-101, 1-2 parts of LUB-501, and 0.5-1 part of antioxidant 1010. The preparation method of the thermoplastic elastomer is: adding dry hydroxyl-terminated polycaprolactone and isofuroone diisocyanate into a polytetrafluoroethylene reaction kettle, adding a catalyst, stirring the system at 70-80 DEG C under a nitrogen atmosphere for 1h, then adding a chain extender, increasing the temperature to 90-100 DEG C and stirring for 30 min, and post-treating to obtain the thermoplastic elastomer.

2. The toughened and reinforced modified PVC material for power protection tubes according to claim 1, characterized by, The catalyst is stannous octoate, and the chain extender is dimethylthiuram disulfide; the amount ratio of the hydroxyl-terminated polycaprolactone, the catalyst and the chain extender is 8-10 g:0.01-0.02 g:1-2 g, and the addition amount of the isofuroone diisocyanate is 0.55 times the total molar amount of hydroxyl groups in the hydroxyl-terminated polycaprolactone.

3. The toughened and reinforced modified PVC material for power protection tubes according to claim 2, characterized by the fact that, The preparation method of the toughening agent is: adding nano-silicon dioxide, an ethanol aqueous solution, 3-[(2-hydroxyethyl)amino]propionic acid methyl ester and a catalyst into a reaction kettle, reacting at 120-150 DEG C for 4-6 h, and post-treating to obtain the toughening agent.

4. The toughened, reinforced, modified PVC material for electrical protection tubes according to claim 1, characterized in that, The catalyst is p-toluenesulfonic acid, and the amount ratio of the nano-silicon dioxide, the ethanol aqueous solution, 3-[(2-hydroxyethyl)amino]propionic acid methyl ester and the catalyst is 1-2 g:20-30 mL:3-5 g:0.1-0.2 g, and the mass fraction of ethanol in the ethanol aqueous solution is 10%.

5. The toughened, reinforced, modified PVC material for power protection tubes according to claim 4, characterized by the fact that, The preparation method of the stabilizer compound is: dissolving chlorinated polyvinyl chloride in cyclohexanone, increasing to 60-80 DEG C, adding methyl methacrylate and azobisisobutyronitrile thereto, reacting for 6-8 h, and post-treating to obtain the stabilizer compound.

6. The toughened, reinforced, modified PVC material for electrical protection tubes according to claim 1, characterized in that, The amount ratio of the chlorinated polyvinyl chloride, the cyclohexanone, the methyl methacrylate and the azobisisobutyronitrile is 10-12 g:50-60 mL:2-3 mL:1-2 g.

7. Toughened, reinforced modified PVC material for power protection tubes according to claim 6, characterized in that, The glass fiber reinforcing agent is prepared by the following steps:

8. The toughened, reinforced, modified PVC material for power protection tubes according to claim 1, characterized by the fact that, A1, slowly adding hydrogen peroxide aqueous solution in glass fiber, dropwise adding 0.5 mol / L sulfuric acid solution, adjusting pH to 4-5, warming and refluxing, filtering, washing with deionized water for 3-5 times, and drying to obtain pretreated glass fiber; A2, adding polyacrylic acid, an ethanol aqueous solution, propyl triethoxy silane isocyanate and dibutyltin dilaurate into a reaction kettle, reacting at 60-80 DEG C under a nitrogen atmosphere for 4-6 h, and post-treating to obtain modified polyacrylic acid; A3, adding modified polyacrylic acid and tetrahydrofuran into a reaction kettle and stirring, increasing the temperature of the reaction kettle to 50-60 DEG C, stirring until the system is dissolved, adding pretreated glass fiber into the reaction kettle and stirring for 30-50 min, adding a catalyst into the reaction kettle, and post-treating after reacting for 60-80 min to obtain the glass fiber reinforcing agent. ​ 9. Toughened, reinforced modified PVC material for power protection tubes according to claim 8, characterized in that, In step A1, the use amount ratio of the glass fiber and the hydrogen peroxide aqueous solution is 1-3g:20-30mL, the mass fraction of hydrogen peroxide in the hydrogen peroxide aqueous solution is 30%; in step A2, the use amount ratio of the polyacrylic acid, the ethanol aqueous solution and dibutyltin dilaurate is 1-2mL:10-20mL:0.05-0.1g, the addition amount of the propyl triethoxy silane isocyanate is 1.05 times of the total moles of carboxyl in the polyacrylic acid, the mass fraction of ethanol in the ethanol aqueous solution is 90%; in step A3, the use amount ratio of the modified polyacrylic acid, tetrahydrofuran, pretreated glass fiber and catalyst is 4-6g:20-30mL:2-3g:0.1-0.2g, the catalyst is p-toluenesulfonic acid.

10. Process for the production of toughened and reinforced modified PVC material for power protection tubes according to any one of claims 1 to 9, characterized in that, The specific content is as follows: PVC, dicumyl peroxide and maleic anhydride are added into a mixing mill, and mixed at 180-220℃ under nitrogen atmosphere for 5-10min, then thermoplastic elastomer is added, after melting and mixing, toughening agent, stabilizer compound, glass fiber reinforcing agent and auxiliary additive are added, and mixed for 10-15min, and then discharged to obtain modified PVC material.

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