Frost-crack-resistant outdoor PVC electric power pipe and preparation method thereof
By using elastomer modifiers and powdered nitrile rubber to synergistically toughen PVC power pipes, along with modified fillers and stabilizers, the problem of PVC power pipes cracking under low-temperature conditions has been solved, improving the toughness and strength of the material and ensuring the safety and reliability of power pipes at low temperatures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-04-03
AI Technical Summary
Existing PVC power pipes have insufficient resistance to freezing and cracking in low-temperature environments, and excessive addition of plasticizers may lead to a decrease in material strength and stability, making it difficult to balance structural support strength and resistance to brittle cracking in low-temperature environments.
An elastomeric modifier and powdered nitrile rubber are used to synergistically toughen the PVC matrix, forming an "island" structure. Combined with modified fillers and stabilizers, frost-resistant outdoor PVC power pipes are prepared through blending modification and extrusion granulation.
This improves the PVC power pipe's resistance to freezing and cracking at low temperatures and its structural strength, ensuring the concealment of power transmission and the safety and reliability of long-term operation.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of advanced petrochemical new materials technology, and in particular to a frost-resistant outdoor PVC power pipe and its preparation method. Background Technology
[0002] As an infrastructure component that carries and protects cables and wires, power conduits are widely used in buildings, industrial facilities, and outdoor power systems. Their core function is to ensure the concealment, physical protection, and long-term operational safety and reliability of power transmission. Polyvinyl chloride (PVC) material is widely used in the manufacture of outdoor power conduits due to its excellent insulation, chemical stability, and ease of processing and molding.
[0003] Ordinary PVC materials have poor low-temperature impact resistance due to the strong intermolecular forces. PVC products are difficult to displace when subjected to external impacts, leading to structural fracture. Existing methods to reduce intermolecular forces in PVC include adding large amounts of plasticizers and CPE, but these methods offer limited improvement in freeze-thaw resistance at low temperatures (below -20°C). Furthermore, excessive plasticizer addition may reduce material strength and stability, making it difficult to balance the structural support strength required for electrical conduits with resistance to brittle fracture at low temperatures. Summary of the Invention
[0004] To improve the anti-freeze cracking performance of PVC power pipes in low-temperature environments, this application provides an anti-freeze cracking outdoor PVC power pipe and its preparation method.
[0005] Firstly, this application provides a frost-resistant outdoor PVC power pipe, which adopts the following technical solution: A frost-resistant outdoor PVC power conduit is prepared from raw materials comprising the following parts by weight: 80-100 parts PVC resin, 6-8 parts elastomer modifier, 5-7 parts powdered nitrile rubber, 12-16 parts modified filler, 1.5-3 parts stabilizer, 0.5-1.5 parts lubricant, 0.1-0.3 parts ultraviolet absorber, and 0.1-0.3 parts antioxidant; The raw materials for preparing the elastomer modifier include alkyl acrylate monomers, allyl methacrylate, and polybutadiene, wherein the mass ratio of the alkyl acrylate monomers, allyl methacrylate, and polybutadiene is 1:(0.01-0.03):(0.1-0.2).
[0006] By adopting the above technical solution, the elastomer modifier and powdered nitrile rubber synergistically toughen the PVC matrix. When blended with the PVC matrix, the particles are uniformly dispersed, forming an "island" structure. Furthermore, the elastomer modifier exhibits good compatibility with the PVC matrix, forming a high-strength interface. When the elastomer modifier is subjected to external impact, it induces shear yielding or generates micro-voids, absorbing a large amount of energy and improving toughening strength. In addition, the powdered nitrile rubber has a low glass transition temperature, effectively improving the embrittlement problem of PVC at low temperatures. The highly polar cyano groups in the powdered nitrile rubber molecular chain have a weak interaction with the chlorine atoms in the PVC molecular chain, allowing for uniform dispersion within the PVC matrix, thus reducing localized embrittlement caused by uneven dispersion.
[0007] Modified fillers act as a reinforcing agent, compensating for the decrease in rigidity and strength of PVC caused by the addition of impact modifiers. Rigid filler particles, under stress, induce cavitation in the surrounding matrix, thereby reducing the thickness of the interparticle matrix bands. This further promotes shear yielding of the matrix and causes the destruction of the matrix network structure, resulting in numerous ligaments and thus further improving the impact performance of the PVC blend system.
[0008] Preferably, the method for preparing the elastomer modifier includes the following steps: Polybutadiene, emulsifier and water are mixed, nitrogen gas is introduced, and the mixture is stirred evenly. The mixture is heated to 70-80℃, alkyl acrylate monomer, allyl methacrylate and initiator are added, and the reaction is maintained at this temperature for 2-4 hours to obtain an elastomer emulsion. After post-treatment, an elastomer modifier is obtained.
[0009] By employing the above technical solution, during the preparation of the elastomer modifier, alkyl acrylate monomers are grafted onto the surface of polybutadiene. From a microscopic perspective, the elastomer modifier forms a good interfacial bond with the PVC matrix, which facilitates stress transfer. Allyl methacrylate contains two unsaturated double bonds, which can improve the grafting efficiency during the grafting process. In the composite material, the elastomer modifier acts as a toughening phase dispersed in the PVC matrix. When the material is subjected to external impact, the elastomer modifier induces crazes and shear bands, absorbing and dispersing impact energy, thereby improving the material's toughness and freeze-thaw resistance.
[0010] Preferably, the alkyl acrylate monomer includes one or more of 2-methyl-2-nonyl acrylate, dodecyl acrylate, and tetradecyl acrylate.
[0011] By adopting the above technical solution, the carbon chain length of the alkyl acrylate monomer mainly affects the glass transition temperature indirectly. Longer carbon chains typically increase chain segment flexibility and lower the glass transition temperature (Tg), allowing the elastomer to maintain a highly elastic state at low temperatures. This enables more effective absorption of impact energy and improves the anti-brittle fracture performance of PVC power pipes in low-temperature environments. Preferably, the emulsifier is sodium dodecyl sulfate and the initiator is potassium persulfate.
[0012] By adopting the above technical solution, sodium dodecyl sulfate, as an emulsifier, can enable polybutadiene, alkyl acrylate monomers, allyl methacrylate, etc. to form a stable emulsion in water, which helps the components to be evenly dispersed and provides a good reaction environment for subsequent reactions. Potassium persulfate, as an initiator, can initiate the polymerization reaction between alkyl acrylate monomers, allyl methacrylate, and polybutadiene, thereby producing an elastomer modifier. This elastomer modifier can reduce the intermolecular forces of PVC and improve the anti-freezing cracking performance of outdoor PVC power pipes in low-temperature environments.
[0013] Preferably, the acrylonitrile content in the powdered nitrile rubber is 12%~20%, and the particle size of the powdered nitrile rubber is 100-200 mesh.
[0014] By adopting the above technical solution, powdered nitrile rubber with low acrylonitrile content is selected, which has excellent elasticity, outstanding low-temperature performance, and good compatibility with PVC.
[0015] Preferably, the method for preparing the modified filler includes the following steps: Nano-calcium carbonate was dispersed in water and stirred evenly. Sodium stearate and water-soluble phosphoaluminate were added, and the mixture was heated to react. After the reaction was completed, the mixture was filtered and dried to obtain the modified filler.
[0016] Preferably, the mass ratio of the nano-calcium carbonate, sodium stearate, and water-soluble phosphoaluminate is 1:(0.02-0.04):(0.02-0.04).
[0017] By adopting the above technical solution, sodium stearate and water-soluble phosphoaluminate are used to modify the surface of nano-calcium carbonate, so as to improve the dispersibility and compatibility of nano-calcium carbonate in PVC matrix.
[0018] Preferably, the stabilizer is one or both of organotin stabilizers and calcium-zinc composite stabilizers.
[0019] More preferably, the organotin stabilizer includes one or both of dibutyltin dilaurate and methyl thiotin.
[0020] Preferably, the lubricant includes one or two of polyethylene wax, ethylene bis-stearamide, and solid paraffin.
[0021] By adopting the above technical solutions, stabilizers can inhibit the thermal and photodegradation reactions of PVC resin during processing and use, reduce material aging due to high temperature or light exposure, and prevent problems such as decomposition and discoloration during processing. Lubricants can improve the mutual friction between the polymer melt and the processing machinery, thereby forming a lubricating film on the surface of the product.
[0022] Preferably, the ultraviolet light absorber includes one or more of UV326, UV327, and UV531.
[0023] Preferably, the antioxidant includes one or more of antioxidant 1010, antioxidant 1076, and antioxidant 168.
[0024] By employing the above technical solution, the ultraviolet absorber selectively and strongly absorbs high-energy ultraviolet rays, converting them into heat energy and releasing it. This prevents the material from absorbing ultraviolet energy and undergoing photochemical reactions, thus preventing aging, discoloration, and embrittlement caused by ultraviolet radiation. Meanwhile, the antioxidant captures free radicals generated during the material's oxidation process, terminating the chain reaction of oxidation, inhibiting oxidative degradation, and protecting the material's performance and structural stability. The synergistic effect of both enhances the anti-freeze cracking ability of outdoor PVC power pipes against ultraviolet rays and oxidation in outdoor environments, extending the service life of the power pipes.
[0025] Secondly, this application provides a method for preparing an anti-freeze-crack outdoor PVC power pipe, which adopts the following technical solution: A method for preparing a frost-resistant outdoor PVC power conduit includes the following steps: PVC resin, elastomer modifier, powdered nitrile rubber, modified filler, stabilizer, lubricant, ultraviolet absorber, and antioxidant are melt-blended, extruded and granulated, and then injection molded to obtain frost-resistant outdoor PVC power pipes.
[0026] By adopting the above technical solution, the preparation method of melt blending, extrusion granulation and injection molding of various raw materials can effectively utilize the characteristics of raw materials, reduce the interaction force between PVC molecules, improve the anti-freezing crack performance of power pipes in low temperature environment, and enable power pipes to take into account both structural support strength and anti-brittle crack performance in low temperature environment, so as to ensure the concealment, physical protection and long-term safe and reliable operation of power transmission.
[0027] This application has the following beneficial effects: 1. Elastomer modifiers and powdered nitrile rubber synergistically toughen the PVC matrix. When blended with the PVC matrix, the particles are uniformly dispersed, forming an "island" structure. Furthermore, the good compatibility with the PVC matrix allows for the formation of a high-strength interface. When the elastomer modifier is subjected to external impact, it induces shear yielding or generates micro-voids, absorbing a large amount of energy and improving toughening strength. In addition, the low glass transition temperature of powdered nitrile rubber effectively improves the low-temperature embrittlement problem of PVC. The highly polar cyano groups in the powdered nitrile rubber molecular chain have a weak interaction with the chlorine atoms in the PVC molecular chain, allowing for uniform dispersion within the PVC matrix and reducing localized embrittlement caused by uneven dispersion.
[0028] Modified fillers act as a reinforcing agent, compensating for the decrease in rigidity and strength of PVC caused by the addition of impact modifiers. Rigid filler particles, under stress, induce cavitation in the surrounding matrix, thereby reducing the thickness of the interparticle matrix bands. This further promotes shear yielding of the matrix and causes the destruction of the matrix network structure, resulting in numerous ligaments and thus further improving the impact performance of the PVC blend system.
[0029] 2. In the preparation of the elastomer modifier, alkyl acrylate monomers are grafted onto the surface of polybutadiene. From a microscopic perspective, the elastomer modifier forms a good interfacial bond with the PVC matrix, which facilitates stress transfer. Allyl methacrylate contains two unsaturated double bonds, which can improve the grafting efficiency during the grafting process. In the composite material, the elastomer modifier acts as a toughening phase dispersed in the PVC matrix. When the material is subjected to external impact, the elastomer modifier induces crazes and shear bands, absorbing and dispersing impact energy, thereby improving the toughness and freeze-cracking resistance of the material. Detailed Implementation
[0030] The present application will be further described in detail below with reference to the embodiments.
[0031] Preparation Example 1 The preparation method of the elastomer modifier includes the following steps: Weigh out alkyl acrylate monomer, allyl methacrylate, and polybutadiene in a mass ratio of 1:0.01:0.1. Specifically, select 2-methyl-2-nonyl acrylate as the alkyl acrylate monomer. The polybutadiene is low-cis polybutadiene, purchased from Henan Runzhihua Chemical Co., Ltd. Weigh out deionized water at 150% of the total mass of the alkyl acrylate monomer, allyl methacrylate, and polybutadiene. Weigh out emulsifier at 1% of the total mass of the alkyl acrylate monomer, allyl methacrylate, and polybutadiene; the emulsifier is sodium dodecyl sulfate. Weigh out initiator at 0.2% of the total mass of the alkyl acrylate monomer, allyl methacrylate, and polybutadiene; the initiator is potassium persulfate.
[0032] Polybutadiene, sodium dodecyl sulfate, and deionized water were mixed, nitrogen gas was introduced, and the mixture was stirred until homogeneous. The mixture was then heated to 70°C, and nonyl 2-methyl-2-acrylate, allyl methacrylate, and potassium persulfate were slowly added dropwise. The mixture was kept at this temperature for 2 hours to obtain an elastomer emulsion. After post-treatment, an elastomer modifier was obtained.
[0033] The post-processing steps are as follows: the elastomer emulsion is demulsified at 65°C using a 0.25 wt% magnesium sulfate solution, and the elastomer modifier is finally obtained after repeated rinsing, filtration and drying.
[0034] Preparation Example 2 The preparation method of the elastomer modifier includes the following steps: Weigh out alkyl acrylate monomer, allyl methacrylate, and polybutadiene according to a mass ratio of 1:0.02:0.15. Specifically, dodecyl acrylate is selected as the alkyl acrylate monomer. The polybutadiene is low-cis polybutadiene, purchased from Henan Runzhihua Chemical Co., Ltd. Weigh out deionized water at 160% of the total mass of the alkyl acrylate monomer, allyl methacrylate, and polybutadiene. Weigh out emulsifier at 1.5% of the total mass of the alkyl acrylate monomer, allyl methacrylate, and polybutadiene. The emulsifier is sodium dodecyl sulfate. Weigh out initiator at 0.3% of the total mass of the alkyl acrylate monomer, allyl methacrylate, and polybutadiene. The initiator is potassium persulfate.
[0035] Polybutadiene, sodium dodecyl sulfate, and deionized water were mixed, nitrogen gas was introduced, and the mixture was stirred until homogeneous. The mixture was then heated to 75°C, and dodecyl acrylate, allyl methacrylate, and potassium persulfate were slowly added dropwise. The mixture was kept at this temperature for 2.5 hours to obtain an elastomer emulsion. After post-treatment, an elastomer modifier was obtained.
[0036] The post-processing steps are as follows: the elastomer emulsion is demulsified at 70°C using a 0.25 wt% magnesium sulfate solution, and the elastomer modifier is finally obtained after repeated rinsing, filtration and drying.
[0037] Preparation Example 3 The preparation method of the elastomer modifier includes the following steps: Weigh out alkyl acrylate monomer, allyl methacrylate, and polybutadiene according to a mass ratio of 1:0.03:0.2. The alkyl acrylate monomer is specifically tetradecyl acrylate. The polybutadiene is low-cis polybutadiene, purchased from Henan Runzhihua Chemical Co., Ltd. Weigh out deionized water at 160% of the total mass of alkyl acrylate monomer, allyl methacrylate, and polybutadiene. Weigh out emulsifier at 2% of the total mass of alkyl acrylate monomer, allyl methacrylate, and polybutadiene. The emulsifier is sodium dodecyl sulfate. Weigh out initiator at 0.4% of the total mass of alkyl acrylate monomer, allyl methacrylate, and polybutadiene. The initiator is potassium persulfate.
[0038] Polybutadiene, sodium dodecyl sulfate, and deionized water were mixed, nitrogen gas was introduced, and the mixture was stirred until homogeneous. The mixture was then heated to 80°C, and tetradecyl acrylate, allyl methacrylate, and potassium persulfate were slowly added dropwise. The mixture was kept at this temperature for 3 hours to obtain an elastomer emulsion. After post-treatment, an elastomer modifier was obtained.
[0039] The post-processing steps are as follows: the elastomer emulsion is demulsified at 65°C using a 0.25 wt% magnesium sulfate solution, and the elastomer modifier is finally obtained after repeated rinsing, filtration and drying.
[0040] Preparation Example 4 The difference between this preparation example and preparation example 3 is that tetradecyl acrylate is replaced by butyl acrylate in equal mass.
[0041] Preparation Example 5 The difference between this preparation example and preparation example 3 is that tetradecyl acrylate is replaced by phenyl acrylate by mass.
[0042] Preparation Example 6 The difference between this preparation example and preparation example 3 is that allyl methacrylate is replaced by propyl methacrylate in equal mass.
[0043] Preliminary Example 1 The preparation method of the modified filler includes the following steps: Weigh nano-calcium carbonate, sodium stearate, and water-soluble aluminum phosphate in a mass ratio of 1:0.02:0.02, and weigh deionized water in a mass ratio of 20 times that of nano-calcium carbonate.
[0044] Nano-calcium carbonate was dispersed in water, stirred evenly, heated to 80°C, sodium stearate and water-soluble phosphoaluminate were added, and the reaction was carried out for 30 minutes. After the reaction was completed, the mixture was filtered and dried to obtain the modified filler.
[0045] Preliminary Example 2 The preparation method of the modified filler includes the following steps: Weigh nano-calcium carbonate, sodium stearate, and water-soluble aluminum phosphate in a mass ratio of 1:0.04:0.04, and weigh deionized water in a mass ratio of 20 times that of nano-calcium carbonate.
[0046] Nano-calcium carbonate was dispersed in water, stirred evenly, heated to 90°C, and sodium stearate and water-soluble phosphoaluminate were added. The mixture was reacted for 40 minutes. After the reaction was completed, the mixture was filtered and dried to obtain the modified filler.
[0047] Example 1 The preparation method of frost-resistant outdoor PVC power pipe includes the following steps: The raw materials are weighed according to the following proportions by weight: 80 parts PVC resin, 6 parts elastomer modifier, 5 parts powdered nitrile rubber, 12 parts modified filler, 1.5 parts stabilizer, 0.5 parts lubricant, 0.1 parts UV absorber, and 0.1 parts antioxidant. The PVC resin is specifically SG-5 type PVC resin. The elastomer modifier is prepared from Preparation Example 1. The powdered nitrile rubber has an acrylonitrile content of 20% and a particle size of 100 mesh. The modified filler is prepared from Preparation Example 1. The stabilizer is specifically dibutyltin dilaurate. The lubricant is specifically solid paraffin wax. The UV absorber is specifically UV531. The antioxidant is specifically antioxidant 1010 and antioxidant 168 compounded in a mass ratio of 1:1.5.
[0048] PVC resin, elastomer modifier, powdered nitrile rubber, modified filler, dibutyltin dilaurate, solid paraffin wax, UV531, antioxidant 1010, and antioxidant 168 were added to a high-speed mixer and melt-blended at 120°C for 1 hour. The mixture was then transferred to a cold mixer and cooled to 50°C. Subsequently, the mixture was transferred to a twin-screw extruder for extrusion granulation and injection molding. The extruder barrel temperature was 220°C, the die temperature was 230°C, and the screw speed was 500 rpm, resulting in a frost-resistant outdoor PVC power pipe.
[0049] Example 2 The preparation method of frost-resistant outdoor PVC power pipe includes the following steps: The raw materials are weighed according to the following proportions by weight: 90 parts PVC resin, 7 parts elastomer modifier, 6 parts powdered nitrile rubber, 14 parts modified filler, 2 parts stabilizer, 1 part lubricant, 0.2 parts UV absorber, and 0.2 parts antioxidant. The PVC resin is specifically SG-5 type PVC resin. The elastomer modifier is prepared from Preparation Example 2. The powdered nitrile rubber has an acrylonitrile content of 16% and a particle size of 200 mesh. The modified filler is prepared from Preparation Example 2. The stabilizer is specifically methyl mercaptan. The lubricant is specifically ethylene bis-stearamide. The UV absorber is specifically UV326. The antioxidant is specifically a mixture of antioxidant 1076 and antioxidant 168 in a mass ratio of 1:2.
[0050] PVC resin, elastomer modifier, powdered nitrile rubber, modified filler, methyl mercaptan, ethylene bis-stearamide, UV326, antioxidant 1076, and antioxidant 168 were added to a high-speed mixer and melt-blended at 120°C for 2 hours. The mixture was then transferred to a cold mixer and cooled to 45°C. Subsequently, the mixture was transferred to a twin-screw extruder for extrusion granulation and injection molding. The extruder barrel temperature was 225°C, the die temperature was 235°C, and the screw speed was 550 rpm, resulting in a frost-resistant outdoor PVC power pipe.
[0051] Example 3 The preparation method of frost-resistant outdoor PVC power pipe includes the following steps: The raw materials were weighed according to the following proportions by weight: 100 parts PVC resin, 8 parts elastomer modifier, 7 parts powdered nitrile rubber, 16 parts modified filler, 3 parts stabilizer, 1.5 parts lubricant, 0.3 parts UV absorber, and 0.3 parts antioxidant. The PVC resin was specifically SG-5 type PVC resin. The elastomer modifier was prepared in Preparation Example 3. The powdered nitrile rubber contained 12% acrylonitrile and had a particle size of 200 mesh. The modified filler was prepared in Preparation Example 2. The stabilizer was specifically dibutyltin dilaurate. The lubricant was specifically polyethylene wax (Clariant Licolub H 22 polyethylene wax). The UV absorber was specifically UV327. The antioxidant was specifically a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2.
[0052] PVC resin, elastomer modifier, powdered nitrile rubber, modified filler, dibutyltin dilaurate, polyethylene wax, UV327, antioxidant 1010, and antioxidant 168 were added to a high-speed mixer and melt-blended at 120°C for 2 hours. The mixture was then transferred to a cold mixer and cooled to 50°C. Subsequently, the mixture was transferred to a twin-screw extruder for extrusion granulation and injection molding. The extruder barrel temperature was 230°C, the die temperature was 240°C, and the screw speed was 600 rpm, resulting in a frost-resistant outdoor PVC power pipe.
[0053] Example 4 The difference between this embodiment and Example 3 is that the elastomer modifier prepared in Example 4 is used.
[0054] Example 5 The difference between this embodiment and Embodiment 3 is that powdered nitrile rubber with an acrylonitrile content of 40% is used.
[0055] Comparative Example 1 The method for preparing the frost-resistant outdoor PVC power pipe differs from that in Example 3 in that the elastomer modifier obtained in Preparation Example 5 is used.
[0056] Comparative Example 2 The method for preparing the frost-resistant outdoor PVC power pipe differs from that in Example 3 in that the elastomer modifier obtained in Preparation Example 6 is used.
[0057] Comparative Example 3 The preparation method of the frost-resistant outdoor PVC power pipe differs from that in Example 3 in that the modified filler is replaced with nano-calcium carbonate.
[0058] Comparative Example 4 The preparation method of the frost-resistant outdoor PVC power pipe differs from that in Example 3 in that no modified filler is added.
[0059] Comparative Example 5 The preparation method of the frost-resistant outdoor PVC power pipe differs from that in Example 3 in that the elastomer modifier is replaced by powdered nitrile rubber.
[0060] Comparative Example 6 The preparation method of the frost-resistant outdoor PVC power pipe differs from that in Example 3 in that the powdered nitrile rubber is replaced by an elastomer modifier. The elastomer modifier is prepared according to Preparation Example 3. Performance testing
[0061] Tensile properties and elongation at break were tested on an ANS tensile testing machine according to GB / T 1040.1-2025 standard. The tensile specimens were type I specimens, the tensile rate was 10 mm / min, and the test temperature was room temperature.
[0062] The impact resistance was tested according to the national standard GB / T 1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams". Before the test, the sample was placed at a temperature of 23℃ and a relative humidity of 50% for 20 hours for adjustment. Notch type: Type A, 5 parallel groups, and the average value was taken.
[0063] Impact embrittlement temperature tests were conducted on Examples 1-5 and Comparative Examples 1-6 according to the requirements of GB / T 5470-2008 and GB / T8815-2008 standards. The units are ℃.
[0064] Table 1
[0065] Based on the comparison between Example 3 and Example 4 and the data in Table 1, it can be seen that: in the elastomer modifier of Example 4, the chain length of the alkyl acrylate monomer may be related to the low-temperature resistance. The longer the chain length, the better the low-temperature resistance. However, Example 4 uses butyl acrylate with a shorter chain length, which does not improve the low-temperature resistance of PVC materials as well as Example 3.
[0066] Based on the comparison between Example 3 and Example 5 and the data in Table 1, it can be seen that: the increase of acrylonitrile content will lead to a decrease in low-temperature performance. As a highly polar monomer, the increase of acrylonitrile content will enhance the polarity of the nitrile rubber molecular chain, thereby increasing the intermolecular forces, reducing the mobility of molecular chain segments, and causing the glass transition temperature to rise, making the material more prone to hardening and brittleness at low temperatures.
[0067] Based on the comparison between Example 3 and Comparative Example 1, and the data in Table 1, it can be seen that the phenyl acrylate structure contains a benzene ring. The introduction of the benzene ring may reduce low-temperature toughness by enhancing the rigidity of the molecular chain. In contrast, the elastomer modifier in Example 3 uses tetradecyl acrylate containing a long carbon chain. Long carbon chains typically increase chain segment flexibility and reduce Tg, allowing the material to maintain toughness at low temperatures, thereby improving the anti-brittleness and crack resistance of PVC power pipes in low-temperature environments.
[0068] Based on the comparison between Example 3 and Comparative Example 2, and the data in Table 1, it can be seen that: the molecular structure of propyl methacrylate contains only one unsaturated double bond. The more obvious the decrease in the degree of crosslinking in the elastomer modifier particles, the lower the notched impact strength of the composite material and the poorer its toughness.
[0069] Based on the comparison between Example 3 and Comparative Examples 3-4, and the data in Table 1, it can be seen that: Comparative Example 3, with the direct addition of unmodified nano-calcium carbonate, exhibits poor compatibility and dispersibility with organic polymers, easily leading to interfacial defects in the composite material and consequently reducing its mechanical strength. In Comparative Example 4, without the addition of modified fillers, the physical properties and structural stability of the PVC material decrease. Under low-temperature conditions, its resistance to freeze-cracking significantly deteriorates, making it difficult to withstand external impacts and prone to breakage.
[0070] Based on the comparison between Example 3 and Comparative Examples 5-6 and the data in Table 1, it can be seen that the elastomer modifier and powdered nitrile rubber synergistically toughen the PVC matrix. The absence of either one will lead to a decrease in the material's low-temperature resistance and crack resistance.
[0071] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A frost-resistant outdoor PVC power conduit, characterized in that, It is prepared from raw materials comprising the following parts by weight: 80-100 parts PVC resin, 6-8 parts elastomer modifier, 5-7 parts powdered nitrile rubber, 12-16 parts modified filler, 1.5-3 parts stabilizer, 0.5-1.5 parts lubricant, 0.1-0.3 parts ultraviolet absorber, and 0.1-0.3 parts antioxidant; The raw materials for preparing the elastomer modifier include alkyl acrylate monomers, allyl methacrylate, and polybutadiene, wherein the mass ratio of the alkyl acrylate monomers, allyl methacrylate, and polybutadiene is 1:(0.01-0.03):(0.1-0.2).
2. The frost-resistant outdoor PVC power conduit according to claim 1, characterized in that, The preparation method of the elastomer modifier includes the following steps: Polybutadiene, emulsifier and water are mixed, nitrogen gas is introduced, and the mixture is stirred evenly. The mixture is heated to 70-80℃, alkyl acrylate monomer, allyl methacrylate and initiator are added, and the reaction is maintained at this temperature for 2-4 hours to obtain an elastomer emulsion. After post-treatment, an elastomer modifier is obtained.
3. The frost-resistant outdoor PVC power conduit according to claim 1, characterized in that, The alkyl acrylate monomers include one or more of 2-methyl-2-nonyl acrylate, dodecyl acrylate, and tetradecyl acrylate.
4. The frost-resistant outdoor PVC power conduit according to claim 1, characterized in that, The emulsifier is sodium dodecyl sulfate, and the initiator is potassium persulfate.
5. The frost-resistant outdoor PVC power conduit according to claim 1, characterized in that, The acrylonitrile content in the powdered nitrile rubber is 12%~20%, and the particle size of the powdered nitrile rubber is 100-200 mesh.
6. The frost-resistant outdoor PVC power conduit according to claim 1, characterized in that, The method for preparing the modified filler includes the following steps: Nano-calcium carbonate was dispersed in water and stirred evenly. Sodium stearate and water-soluble phosphoaluminate were added, and the mixture was heated to react. After the reaction was completed, the mixture was filtered and dried to obtain the modified filler.
7. The frost-resistant outdoor PVC power conduit according to claim 6, characterized in that, The mass ratio of the nano-calcium carbonate, sodium stearate, and water-soluble phosphoaluminate is 1:(0.02-0.04):(0.02-0.04).
8. The frost-resistant outdoor PVC power conduit according to claim 1, characterized in that, The stabilizer is one or two of organotin stabilizers and calcium-zinc composite stabilizers; the lubricant includes one or two of polyethylene wax, ethylene bis-stearamide, and solid paraffin wax.
9. The frost-resistant outdoor PVC power conduit according to claim 1, characterized in that, The ultraviolet light absorber includes one or more of UV326, UV327, and UV531; the antioxidant includes one or more of antioxidant 1010, antioxidant 1076, and antioxidant 168.
10. A method for preparing a frost-resistant outdoor PVC power conduit according to any one of claims 1-9, characterized in that, Includes the following steps: PVC resin, elastomer modifier, powdered nitrile rubber, modified filler, stabilizer, lubricant, ultraviolet absorber, and antioxidant are melt-blended, extruded and granulated, and then injection molded to obtain frost-resistant outdoor PVC power pipes.