Low-damping PVC-U electrical conduit and processing technology thereof

Abstract

The invention discloses a low-damping PVC-U electrical conduit and a processing technology thereof, and belongs to the technical field of conduit preparation. The low-damping PVC-U electrical conduit is prepared from the following components in parts by weight: 70 to 80 parts of PVC resin, 30 to 42 parts of light calcium carbonate, 8 to 15 parts of ethylene-vinyl acetate copolymer, 0.5 to 1 part of ethylene bis stearamide, 3 to 6 parts of epoxy compound and 4 to 7 parts of compound stabilizer, the preparation method comprises the following steps: preparing an epoxy compound from ethyl benzoylacetate, 2-(trimethylsilyl) phenyl trifluoromethane sulfonate, p-toluenesulfonyl azide, p-aminophenol, p-toluenesulfonyl chloride, iodobenzene diacetic acid and rhodium diacetate as raw materials, and preparing the compound stabilizer from 2-(2-aminoethoxy) ethanol, 4-fluorophenol and xylene alkane diisocyanate as raw materials. The PVC-U electrical conduit prepared from the substances has the advantages of low damping, excellent stability, excellent mechanical property and excellent aging resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of electrical casing preparation, and in particular relates to a low-damping PVC-U electrical casing and a processing technology thereof. Background Art

[0002] PVC-U electrical conduit, a widely used cable protection material in building power projects, faces a critical challenge in its development due to its material properties and performance limitations. Based on polyvinyl chloride resin and modified with additives such as stabilizers and lubricants, this material offers advantages such as excellent insulation, strong corrosion resistance, and easy construction. However, its damping performance and thermal stability continue to constrain its expansion.

[0003] The strong van der Waals forces between PVC molecular chains make the material prone to molecular chain slippage and rearrangement under mechanical stress, dissipating energy in the form of heat. This characteristic not only gives the casing good impact resistance during dynamic construction such as concrete pouring—it can withstand normal tamping without breaking—but also facilitates on-site bending and forming. However, the flip side of high damping is that stress easily accumulates within the material. When exposed to vibration for a long time or repeatedly deformed, it is easy to cause molecular chain breakage at the microscopic level, forming microcracks that gradually expand and ultimately affect structural integrity and service life. At the same time, PVC-U's thermal stability shortcomings are particularly prominent: its thermal decomposition temperature is approximately 140°C. When the ambient temperature exceeds 70°C, a small amount of unstable structures in the material begin to dehydrogenate HCl, forming conjugated double bonds, causing the color to turn yellow and physical properties to deteriorate.

[0004] Patent CN107987412A discloses low-smoke, high-flame-retardant PVC electrical conduit, which is composed of the following ingredients by weight: 90-110 parts of PVC resin, 3-5 parts of chlorinated polyethylene, 3-7 parts of stabilizer, 10-20 parts of filler, 6-8 parts of calcium carbonate whiskers, 10-20 parts of flame retardant, and 4-6 parts of processing aid. The flame retardant is a combination of 3-6 parts of zinc borate, 1.5-3 parts of zinc stannate, 2-3 parts of ammonium octamolybdate, 1-2 parts of nanoclay, 1.5-3 parts of melamine phosphate, and 1-3 parts of ammonium polyphosphate. The low-smoke, high-flame-retardant PVC electrical conduit of the invention has good environmental performance and excellent flame retardant properties, suitable smoke emission, good tensile strength and elongation, high oxygen index, and good low-temperature impact performance. In terms of thermal stability, while the stabilizer used meets basic processing requirements, its ability to inhibit the HCl removal reaction of PVC is weak during high-temperature processing and long-term heat aging. Furthermore, the lack of synergistic effects from auxiliary stabilizers leads to the accumulation of acidic substances, accelerating material degradation and discoloration. Furthermore, while chlorinated polyethylene, as an elastomer, can improve toughness, the dosage is insufficient to form an effective sea-island phase separation structure. Furthermore, the rigid filling of calcium carbonate whiskers reduces the chain segment mobility, resulting in reduced energy dissipation efficiency. Summary of the Invention

[0005] The object of the present invention is to provide a low-damping PVC-U electrical conduit and a processing technology thereof, so as to solve the technical problem of poor thermal stability of electrical conduits in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The invention provides a low-damping PVC-U electrical conduit, which is composed of the following components in parts by weight: 70-80 parts of PVC resin, 30-42 parts of light calcium carbonate, 8-15 parts of ethylene-vinyl acetate copolymer, 0.5-1 part of vinyl bisstearamide, 3-6 parts of epoxy compound and 4-7 parts of composite stabilizer.

[0008] Preferably, the method for preparing the epoxy compound comprises the following steps:

[0009] Q1: Ethyl benzoyl acetate and 2-(trimethylsilyl)phenyl trifluoromethanesulfonate were added to a container, acetonitrile was added under a nitrogen atmosphere, and cesium fluoride was then slowly added. The reaction was refluxed. After the reaction was completed, the mixture was cooled, extracted, washed, dried, filtered under reduced pressure, and purified to obtain compound 1. Under a nitrogen atmosphere, compound 1 was added to acetonitrile, and p-toluenesulfonyl azide was then added and stirred. Subsequently, diazabicyclic was added dropwise, stirred at room temperature, and purified to obtain compound 2.

[0010] Q2: p-Aminophenol and dichloromethane were added to a container, pyridine was added dropwise, p-toluenesulfonyl chloride was added to dichloromethane, stirred to dissolve, and then slowly added dropwise to the container. After the addition was complete, the mixture was stirred at room temperature for reaction. After the reaction was completed, the mixture was extracted, dried, evaporated under reduced pressure, and purified to obtain compound 3. Compound 3 and dichloromethane were added to a container, iodophenyldiacetic acid was slowly added under ice bath, stirred for reaction, extracted, dried, evaporated under reduced pressure, and recrystallized to obtain compound 4.

[0011] Q3: Add compound 4, dimerized rhodium acetate and propargyl alcohol to a container, add chloroform under nitrogen environment, stir at room temperature, add compound 2 to chloroform, stir to dissolve, add dropwise to the container, stir to react, and after the reaction is completed, purify to obtain an epoxy complex.

[0012] In the above process, the synthesis reaction formula of the epoxy compound is as follows:

[0013]

[0014] The results of mass spectrometry analysis of compound 1 were: m / z: 268.11 (100.0%), 269.11 (18.5%), 270.12 (1.6%); the results of mass spectrometry analysis of compound 2 were: m / z: 294.10 (100.0%), 295.10 (19.2%), 296.11 (1.6%); the results of mass spectrometry analysis of compound 3 were: m / z: 263.06 (100.0%), 264.06 (15.2%), 265.06 (4.7%), 265 .07 (1.6%); the results of mass spectrometry analysis of compound 4 were: m / z: 261.05 (100.0%), 262.05 (15.1%), 263.04 (4.5%), 263.05 (1.7%); the results of mass spectrometry analysis of epoxy complex were: m / z: 527.14 (100.0%), 528.14 (33.8%), 529.14 (6.1%), 529.15 (5.3%), 530.14 (1.5%), 530.15 (1.0%).

[0015] Preferably, in Q1, the molar ratio of ethyl benzoylacetate, 2-(trimethylsilyl)phenyl trifluoromethanesulfonate and cesium fluoride is (1-2): (1.5-2.5): (2.5-4.3), and the reflux reaction is carried out for 2-3 hours; the molar ratio of compound 1, p-toluenesulfonyl azide and diazabicycle is (1-1.5): (1.5-2.2): (1.5-2.3), the stirring time is 10-15 minutes, and the stirring reaction time at room temperature is 10-12 hours.

[0016] Preferably, in Q2, the usage ratio of p-aminophenol, pyridine and p-toluenesulfonyl chloride is (1-1.5) g: (2.9-3.5) mL: (2.1-2.8) g; the usage ratio of compound 3, dichloromethane and iodophenyldiacetic acid is (2-2.5) g: (30-45) mL: (4.9-6.2) g, and the stirring reaction time is 1-2 h.

[0017] Preferably, in Q3, the molar ratio of compound 4, dimerized rhodium acetate, propargyl alcohol and compound 2 is (0.2-0.28): (0.05-0.09): (0.1-0.12): (0.2-0.29).

[0018] Preferably, the preparation method of the composite stabilizer comprises the following steps:

[0019] S1: Add 2-(2-aminoethoxy)ethanol and formaldehyde aqueous solution to a container containing 1,4-dioxane, stir in an ice bath to react, then add 4-fluorophenol, heat and stir under reflux to react, cool, distill under reduced pressure, dissolve, wash, and dry in vacuo to obtain organic compound a;

[0020] S2: Add organic matter a to a container containing 1,4-dioxane, then add dibutyltin dilaurate, stir under nitrogen environment, then add dimethylbenzene diisocyanate, heat and reflux to react, after the reaction is completed, distill under reduced pressure, dissolve, wash, vacuum dry, and purify to obtain a composite stabilizer.

[0021] In the above process, the synthetic reaction formula of the composite stabilizer is as follows:

[0022]

[0023] The results of mass spectrometry analysis of organic compound a were: m / z: 241.11 (100.0%), 242.11 (13.3%), 243.12 (1.4%); the results of mass spectrometry analysis of the composite stabilizer were: m / z: 732.30 (100.0%), 733.30 (43.0%), 734.30 (11.1%), 733.29 (1.5%), 735.31 (1.2%).

[0024] Preferably, in S1, the amount ratio of 2-(2-aminoethoxy)ethanol, formaldehyde aqueous solution and 4-fluorophenol is (6.92-10.56) g: (9.2-10.7) mL: (6.72-10.08) g, the stirring reaction time is 30-45 min, and the temperature is raised to 90-94° C. and stirred under reflux for 20-24 h.

[0025] Preferably, in S2, the amount ratio of organic matter a, 1,4-dioxane, dibutyltin dilaurate and ditoluene diisocyanate is (4.5-5.6) g: (30-45) mL: (0.2-0.25) g: (2-3.2) mL, the stirring time is 10-15 min, and the temperature is raised to 80-83° C. and refluxed for 12-17 h.

[0026] Preferably, the processing technology of the low-damping PVC-U electrical casing comprises the following steps:

[0027] Step 1: Add PVC resin, light calcium carbonate, epoxy compound and composite stabilizer into a container, mix, and preheat to obtain a mixture;

[0028] Step 2: The mixture is heated, and then ethylene-vinyl acetate copolymer is added, and the mixing is continued. Then, vinyl bisstearamide is added, and after mixing evenly, cold mixing, extrusion, and shaping are performed to obtain a low-damping PVC-U electrical conduit.

[0029] Preferably, in step one, the preheating temperature is 80-90°C; in step two, the heating treatment temperature is 110-120°C, and the continuous mixing temperature is 120-130°C.

[0030] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0031] 1. In the preparation of PVC-U electrical conduits, the present invention adds ethylene-vinyl acetate copolymer as a toughening agent. The flexible chain segments contained therein can absorb vibration energy, convert mechanical properties into heat energy through the slip and reorganization of molecular chains, and reduce the transmission efficiency of stress waves within the material. The added epoxy compound can form a network structure through a cross-linking reaction, inhibit excessive sliding of molecular chains, and reduce energy loss caused by segment friction. The addition of a composite stabilizer can also form a micro-region phase separation structure, absorb vibration energy, and reduce damping. In addition, the added epoxy compound and composite stabilizer can also improve the material's stability, mechanical properties, and aging resistance.

[0032] 2. The prepared epoxy composite is added to PVC-U electrical conduits to effectively improve their thermal stability and mechanical properties. The epoxy groups in the epoxy composite undergo a nucleophilic addition reaction with HCl generated by thermal degradation of PVC, consuming HCl and inhibiting its catalytic chain scission on the PVC chain, thereby delaying yellowing of the material. Furthermore, the cyclic structure in the epoxy composite forms strong van der Waals forces with the PVC chain segments, enhancing the rigidity of the material. The presence of sulfonyl and ester groups can interact with the carbon-chlorine bond dipoles of PVC, reducing phase separation.

[0033] 3. The present invention adds the prepared composite stabilizer to the PVC-U electrical conduit, which can effectively improve its stability, mechanical properties and aging resistance. The cross-linked network contained in the composite stabilizer structure is combined with the PVC molecular chain through hydrogen bonds, reducing degradation sites and delaying thermal decomposition. At the same time, it can also improve the mechanical properties of the PVC material, reduce microcracks caused by mechanical stress, and ensure the integrity of the material. The synergistic effect of the oxygen-nitrogen heterocycle, fluorine atoms, ether bonds and amide structures contained in the composite stabilizer improves the aging resistance of the material. DETAILED DESCRIPTION

[0034] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] Example 1: This example discloses a method for preparing an epoxy compound, comprising the following steps:

[0036] Q1: 2.883 g of ethyl benzoyl acetate and 5.967 g of 2-(trimethylsilyl)phenyl trifluoromethanesulfonate were added to a container, and under a nitrogen environment, 10 mL of acetonitrile was added, followed by slow addition of 5.165 g of cesium fluoride, and the reaction was refluxed for 2 h. After the reaction was completed, the mixture was cooled, extracted, washed, dried, filtered under reduced pressure, and purified to obtain compound 1; under a nitrogen environment, 0.335 g of compound 1 was added to 10 mL of acetonitrile, and then 0.364 g of p-toluenesulfonyl azide was added at 0°C and stirred for 10 min, followed by dropwise addition of 0.291 g of diazabicyclo, and stirred at room temperature for 12 h. After the reaction was completed, the mixture was purified to obtain compound 2;

[0037] Q2: 1.25 g of p-aminophenol and 20 mL of dichloromethane were added to a container, 3.2 mL of pyridine was added dropwise, 2.45 g of p-toluenesulfonyl chloride was added to 8 mL of dichloromethane, stirred to dissolve, and then slowly added dropwise to the container. After the addition was complete, the mixture was stirred at room temperature for reaction. After the reaction was completed, the mixture was extracted, dried, evaporated under reduced pressure, and purified to obtain compound 3; 2.25 g of compound 3 and 37.5 mL of dichloromethane were added to a container, 5.5 g of iodophenyldiacetic acid was slowly added under ice bath, stirred for reaction for 2 h, extracted, dried, evaporated under reduced pressure, and recrystallized to obtain compound 4;

[0038] Q3: Add 0.625g of compound 4, 0.31g of dimerized rhodium acetate and 0.0616g of propargyl alcohol into a container. Under nitrogen environment, add 2mL of chloroform and stir at room temperature. Add 0.72g of compound 2 into 0.5mL of chloroform, stir to dissolve, and then add dropwise into the container. Stir to react. After the reaction is completed, purify to obtain an epoxy complex.

[0039] This embodiment discloses a method for preparing a composite stabilizer, comprising the following steps:

[0040] S1: 8.74 g of 2-(2-aminoethoxy)ethanol and 9.8 mL of 37% formaldehyde aqueous solution were added to a container containing 30 mL of 1,4-dioxane, and the mixture was stirred in an ice bath for 30 min. Subsequently, 8.35 g of 4-fluorophenol was added, and the mixture was heated to 90°C and stirred under reflux for 24 h. The mixture was then cooled, distilled under reduced pressure, dissolved, washed, and dried in vacuo to obtain organic compound a;

[0041] S2: Add 4.8 g of organic matter a to a container containing 37.5 mL of 1,4-dioxane, then add 0.22 g of dibutyltin dilaurate, stir for 10 min under nitrogen environment, then add 2.6 mL of dimethylbenzene diisocyanate, heat to 80 ° C and reflux for 15 h. After the reaction is completed, distill under reduced pressure, dissolve, wash, vacuum dry, and purify to obtain a composite stabilizer.

[0042] This embodiment discloses a low-damping PVC-U electrical conduit, which is composed of the following components by weight: 75 parts of PVC resin, 36 parts of light calcium carbonate, 11 parts of ethylene-vinyl acetate copolymer, 0.75 parts of vinyl bisstearamide, 4.5 parts of epoxy compound and 5.5 parts of composite stabilizer.

[0043] This embodiment discloses a processing technology for low-damping PVC-U electrical casing, comprising the following steps:

[0044] Step 1: Add PVC resin, light calcium carbonate, epoxy compound and composite stabilizer into a container, mix, and preheat at 90°C to obtain a mixture;

[0045] Step 2: Heat the mixture to 110°C, then add ethylene-vinyl acetate copolymer, continue mixing at 120°C, then add vinyl bisstearamide, mix evenly, cold mix, extrude, and shape to obtain low-damping PVC-U electrical conduit.

[0046] Example 2: This example discloses a method for preparing an epoxy compound, comprising the following steps:

[0047] Q1: 1.922 g of ethyl benzoyl acetate and 4.475 g of 2-(trimethylsilyl)phenyl trifluoromethanesulfonate were added to a container. Under a nitrogen environment, 10 mL of acetonitrile was added, followed by the slow addition of 3.797 g of cesium fluoride. The reaction was refluxed for 2 h. After the reaction was completed, the mixture was cooled, extracted, washed, dried, filtered under reduced pressure, and purified to obtain compound 1. Under a nitrogen environment, 0.268 g of compound 1 was added to 10 mL of acetonitrile, followed by the addition of 0.295 g of p-toluenesulfonyl azide at 0°C and stirred for 10 min. Subsequently, 0.229 g of diazabicyclo was added dropwise and stirred at room temperature for 12 h. After the reaction was completed, the mixture was purified to obtain compound 2.

[0048] Q2: 1.5 g of p-aminophenol and 20 mL of dichloromethane were added to a container, 2.9 mL of pyridine was added dropwise, 2.1 g of p-toluenesulfonyl chloride was added to 8 mL of dichloromethane, stirred to dissolve, and then slowly added dropwise to the container. After the addition was complete, the mixture was stirred at room temperature for reaction. After the reaction was completed, the mixture was extracted, dried, evaporated under reduced pressure, and purified to obtain compound 3; 2 g of compound 3 and 30 mL of dichloromethane were added to a container, 4.9 g of iodophenyldiacetic acid was slowly added under ice bath, stirred for reaction for 2 h, extracted, dried, evaporated under reduced pressure, and recrystallized to obtain compound 4;

[0049] Q3: Add 0.522g of compound 4, 0.22g of dimerized rhodium acetate and 0.056g of propargyl alcohol into a container. Under nitrogen environment, add 2mL of chloroform and stir at room temperature. Add 0.58g of compound 2 into 0.5mL of chloroform, stir to dissolve, and then add dropwise into the container. Stir to react. After the reaction is completed, purify to obtain an epoxy complex.

[0050] This embodiment discloses a method for preparing a composite stabilizer, comprising the following steps:

[0051] S1: 6.92 g of 2-(2-aminoethoxy)ethanol and 9.2 mL of 37% formaldehyde aqueous solution were added to a container containing 30 mL of 1,4-dioxane, and the mixture was stirred in an ice bath for 30 min. Subsequently, 6.72 g of 4-fluorophenol was added, and the mixture was heated to 90°C and stirred under reflux for 24 h. The mixture was then cooled, distilled under reduced pressure, dissolved, washed, and dried in vacuo to obtain organic compound a;

[0052] S2: Add 4.5 g of organic matter a to a container containing 30 mL of 1,4-dioxane, then add 0.25 g of dibutyltin dilaurate, stir for 10 min under nitrogen environment, then add 2 mL of dimethylbenzene diisocyanate, heat to 80 ° C and reflux for 15 h. After the reaction is completed, distill under reduced pressure, dissolve, wash, vacuum dry, and purify to obtain a composite stabilizer.

[0053] This embodiment discloses a low-damping PVC-U electrical conduit, which is composed of the following components by weight: 70 parts of PVC resin, 30 parts of light calcium carbonate, 15 parts of ethylene-vinyl acetate copolymer, 1 part of vinyl bisstearamide, 3 parts of epoxy compound and 4 parts of composite stabilizer.

[0054] This embodiment discloses a processing technology for low-damping PVC-U electrical casing, comprising the following steps:

[0055] Step 1: Add PVC resin, light calcium carbonate, epoxy compound and composite stabilizer into a container, mix, and preheat at 90°C to obtain a mixture;

[0056] Step 2: Heat the mixture to 110°C, then add ethylene-vinyl acetate copolymer, continue mixing at 120°C, then add vinyl bisstearamide, mix evenly, cold mix, extrude, and shape to obtain low-damping PVC-U electrical conduit.

[0057] Example 3: This example discloses a method for preparing an epoxy compound, comprising the following steps:

[0058] Q1: 3.844 g of ethyl benzoyl acetate and 7.458 g of 2-(trimethylsilyl)phenyl trifluoromethanesulfonate were added to a container. Under a nitrogen environment, 10 mL of acetonitrile was added, followed by the slow addition of 6.531 g of cesium fluoride. The reaction was refluxed for 2 h. After the reaction was completed, the mixture was cooled, extracted, washed, dried, filtered under reduced pressure, and purified to obtain compound 1. Under a nitrogen environment, 0.402 g of compound 1 was added to 10 mL of acetonitrile, followed by the addition of 0.433 g of p-toluenesulfonyl azide at 0°C and stirred for 10 min. Subsequently, 0.352 g of diazabicyclic was added dropwise and stirred at room temperature for 12 h. After the reaction was completed, the mixture was purified to obtain compound 2.

[0059] Q2: 1 g of p-aminophenol and 20 mL of dichloromethane were added to a container, 3.5 mL of pyridine was added dropwise, 2.8 g of p-toluenesulfonyl chloride was added to 8 mL of dichloromethane, stirred to dissolve, and then slowly added dropwise to the container. After the addition was complete, the mixture was stirred at room temperature for reaction. After the reaction was completed, the mixture was extracted, dried, evaporated under reduced pressure, and purified to obtain compound 3; 2.5 g of compound 3 and 45 mL of dichloromethane were added to a container, 6.2 g of iodophenyldiacetic acid was slowly added under ice bath, stirred for reaction for 2 h, extracted, dried, evaporated under reduced pressure, and recrystallized to obtain compound 4;

[0060] Q3: Add 0.73g of compound 4, 0.39g of dimerized rhodium acetate and 0.067g of propargyl alcohol into a container. Under nitrogen environment, add 2mL of chloroform and stir at room temperature. Add 0.85g of compound 2 into 0.5mL of chloroform, stir to dissolve, and then add dropwise into the container. Stir to react. After the reaction is completed, purify to obtain an epoxy complex.

[0061] This embodiment discloses a method for preparing a composite stabilizer, comprising the following steps:

[0062] S1: 10.56 g of 2-(2-aminoethoxy)ethanol and 10.7 mL of 37% formaldehyde aqueous solution were added to a container containing 30 mL of 1,4-dioxane, and the mixture was stirred in an ice bath for 30 min. Subsequently, 10.08 g of 4-fluorophenol was added, and the mixture was heated to 90°C and stirred under reflux for 24 h. The mixture was then cooled, distilled under reduced pressure, dissolved, washed, and dried in vacuo to obtain organic compound a;

[0063] S2: Add 5.6 g of organic matter a to a container containing 45 mL of 1,4-dioxane, then add 0.2 g of dibutyltin dilaurate, stir for 10 minutes under nitrogen environment, then add 3.2 mL of dimethylbenzene diisocyanate, heat to 80 ° C and reflux for 15 hours. After the reaction is completed, distill under reduced pressure, dissolve, wash, vacuum dry, and purify to obtain a composite stabilizer.

[0064] This embodiment discloses a low-damping PVC-U electrical conduit, which is composed of the following components by weight: 80 parts of PVC resin, 42 parts of light calcium carbonate, 8 parts of ethylene-vinyl acetate copolymer, 0.5 parts of vinyl bisstearamide, 6 parts of epoxy compound and 7 parts of composite stabilizer.

[0065] This embodiment discloses a processing technology for low-damping PVC-U electrical casing, comprising the following steps:

[0066] Step 1: Add PVC resin, light calcium carbonate, epoxy compound and composite stabilizer into a container, mix, and preheat at 90°C to obtain a mixture;

[0067] Step 2: Heat the mixture to 110°C, then add ethylene-vinyl acetate copolymer, continue mixing at 120°C, then add vinyl bisstearamide, mix evenly, cold mix, extrude, and shape to obtain low-damping PVC-U electrical conduit.

[0068] Example 4: This example discloses a method for preparing an epoxy compound, comprising the following steps:

[0069] Q1: 2.417 g of ethyl benzoyl acetate and 5.217 g of 2-(trimethylsilyl)phenyl trifluoromethanesulfonate were added to a container, and under a nitrogen environment, 10 mL of acetonitrile was added, followed by slow addition of 4.712 g of cesium fluoride, and the reaction was refluxed for 2 h. After the reaction was completed, the mixture was cooled, extracted, washed, dried, filtered under reduced pressure, and purified to obtain compound 1; under a nitrogen environment, 0.292 g of compound 1 was added to 10 mL of acetonitrile, and then 0.315 g of p-toluenesulfonyl azide was added at 0°C and stirred for 10 min, followed by dropwise addition of 0.258 g of diazabicyclic, and stirred at room temperature for 12 h. After the reaction was completed, the mixture was purified to obtain compound 2;

[0070] Q2: 1.1 g of p-aminophenol and 20 mL of dichloromethane were added to a container, 3.1 mL of pyridine was added dropwise, 2.2 g of p-toluenesulfonyl chloride was added to 8 mL of dichloromethane, stirred to dissolve, and then slowly added dropwise to the container. After the addition was complete, the mixture was stirred at room temperature for reaction. After the reaction was completed, the mixture was extracted, dried, evaporated under reduced pressure, and purified to obtain compound 3; 2.1 g of compound 3 and 32 mL of dichloromethane were added to a container, 5.1 g of iodophenyldiacetic acid was slowly added under ice bath, stirred for reaction for 2 h, extracted, dried, evaporated under reduced pressure, and recrystallized to obtain compound 4;

[0071] Q3: Add 0.587g of compound 4, 0.27g of dimerized rhodium acetate and 0.058g of propargyl alcohol into a container. Under nitrogen environment, add 2mL of chloroform and stir at room temperature. Add 0.63g of compound 2 into 0.5mL of chloroform, stir to dissolve, and then add dropwise into the container. Stir to react. After the reaction is completed, purify to obtain an epoxy complex.

[0072] This embodiment discloses a method for preparing a composite stabilizer, comprising the following steps:

[0073] S1: 7.23 g of 2-(2-aminoethoxy)ethanol and 9.5 mL of 37% formaldehyde aqueous solution were added to a container containing 30 mL of 1,4-dioxane, and the mixture was stirred in an ice bath for 30 min. Subsequently, 7.54 g of 4-fluorophenol was added, and the mixture was heated to 90°C and stirred under reflux for 24 h. The mixture was then cooled, distilled under reduced pressure, dissolved, washed, and dried in vacuo to obtain organic compound a;

[0074] S2: Add 4.7 g of organic matter a to a container containing 35 mL of 1,4-dioxane, then add 0.21 g of dibutyltin dilaurate, stir for 10 min under nitrogen environment, then add 2.7 mL of dimethylbenzene diisocyanate, heat to 80 ° C and reflux for 15 h. After the reaction is completed, distill under reduced pressure, dissolve, wash, vacuum dry, and purify to obtain a composite stabilizer.

[0075] This embodiment discloses a low-damping PVC-U electrical conduit, which is composed of the following components by weight: 72 parts of PVC resin, 33 parts of light calcium carbonate, 9 parts of ethylene-vinyl acetate copolymer, 0.7 parts of vinyl bisstearamide, 4 parts of epoxy compound and 5 parts of composite stabilizer.

[0076] This embodiment discloses a processing technology for low-damping PVC-U electrical casing, comprising the following steps:

[0077] Step 1: Add PVC resin, light calcium carbonate, epoxy compound and composite stabilizer into a container, mix, and preheat at 90°C to obtain a mixture;

[0078] Step 2: Heat the mixture to 110°C, then add ethylene-vinyl acetate copolymer, continue mixing at 120°C, then add vinyl bisstearamide, mix evenly, cold mix, extrude, and shape to obtain low-damping PVC-U electrical conduit.

[0079] Example 5: This example discloses a method for preparing an epoxy compound, comprising the following steps:

[0080] Q1: 3.402 g of ethyl benzoyl acetate and 6.873 g of 2-(trimethylsilyl)phenyl trifluoromethanesulfonate were added to a container. Under a nitrogen atmosphere, 10 mL of acetonitrile was added, followed by the slow addition of 5.835 g of cesium fluoride. The reaction was refluxed for 2 h. After the reaction was completed, the mixture was cooled, extracted, washed, dried, filtered under reduced pressure, and purified to obtain compound 1. Under a nitrogen atmosphere, 0.387 g of compound 1 was added to 10 mL of acetonitrile, followed by the addition of 0.397 g of p-toluenesulfonyl azide at 0°C and the stirring for 10 min. Subsequently, 0.301 g of diazabicyclo was added dropwise, and the mixture was stirred at room temperature for 12 h. After the reaction was completed, the mixture was purified to obtain compound 2.

[0081] Q2: 1.4 g of p-aminophenol and 20 mL of dichloromethane were added to a container, 3.4 mL of pyridine was added dropwise, 2.7 g of p-toluenesulfonyl chloride was added to 8 mL of dichloromethane, stirred to dissolve, and then slowly added dropwise to the container. After the addition was complete, the mixture was stirred at room temperature for reaction. After the reaction was completed, the mixture was extracted, dried, evaporated under reduced pressure, and purified to obtain compound 3; 2.4 g of compound 3 and 42 mL of dichloromethane were added to a container, 5.8 g of iodophenyldiacetic acid was slowly added under ice bath, stirred for reaction for 2 h, extracted, dried, evaporated under reduced pressure, and recrystallized to obtain compound 4;

[0082] Q3: Add 0.685g of compound 4, 0.34g of dimerized rhodium acetate and 0.064g of propargyl alcohol into a container. Under nitrogen environment, add 2mL of chloroform and stir at room temperature. Add 0.78g of compound 2 into 0.5mL of chloroform, stir to dissolve, and then add dropwise into the container. Stir to react. After the reaction is completed, purify to obtain an epoxy complex.

[0083] This embodiment discloses a method for preparing a composite stabilizer, comprising the following steps:

[0084] S1: 9.17 g of 2-(2-aminoethoxy)ethanol and 10.2 mL of 37% formaldehyde aqueous solution were added to a container containing 30 mL of 1,4-dioxane, and the mixture was stirred in an ice bath for 30 min. Subsequently, 9.23 g of 4-fluorophenol was added, and the mixture was heated to 90°C and stirred under reflux for 24 h. The mixture was then cooled, distilled under reduced pressure, dissolved, washed, and dried in vacuo to obtain organic compound a;

[0085] S2: Add 5.2 g of organic matter a to a container containing 40 mL of 1,4-dioxane, then add 0.24 g of dibutyltin dilaurate, stir for 10 min under nitrogen environment, then add 2.3 mL of dimethylbenzene diisocyanate, heat to 80 ° C and reflux for 15 h. After the reaction is completed, distill under reduced pressure, dissolve, wash, vacuum dry, and purify to obtain a composite stabilizer.

[0086] This embodiment discloses a low-damping PVC-U electrical conduit, which is composed of the following components by weight: 78 parts of PVC resin, 39 parts of light calcium carbonate, 14 parts of ethylene-vinyl acetate copolymer, 0.9 parts of vinyl bisstearamide, 5 parts of epoxy compound and 6 parts of composite stabilizer.

[0087] This embodiment discloses a processing technology for low-damping PVC-U electrical casing, comprising the following steps:

[0088] Step 1: Add PVC resin, light calcium carbonate, epoxy compound and composite stabilizer into a container, mix, and preheat at 90°C to obtain a mixture;

[0089] Step 2: Heat the mixture to 110°C, then add ethylene-vinyl acetate copolymer, continue mixing at 120°C, then add vinyl bisstearamide, mix evenly, cold mix, extrude, and shape to obtain low-damping PVC-U electrical conduit.

[0090] Comparative Example 1: Compared with Example 1, in the process of preparing the low-damping PVC-U electrical bushing in Comparative Example 1, no epoxy compound is added, and other conditions remain unchanged.

[0091] Comparative Example 2: Compared with Example 1, in the process of preparing the low-damping PVC-U electrical casing in Comparative Example 2, no composite stabilizer is added, and other conditions remain unchanged.

[0092] Performance testing:

[0093] The PVC-U electrical conduits prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to performance tests. The tensile properties of the samples were tested according to ISO 6259-2:2020, the heat resistance of the samples was tested according to GB / T 43815-2024, and the aging resistance of the samples was tested according to GB / T 2951.12-2008. The damping performance of the samples was tested using DMA at a test frequency of 1 Hz and a temperature of 27±2°C. The test results are shown in Table 1:

[0094] Table 1

[0095] project Yield stress / MPa Elongation at break / % Indentation diameter / mm Tensile retention rate / % loss factor Example 1 54.3 103.6 1.06 89.6 0.02 Example 2 53.4 103.1 1.09 89.5 0.02 Example 3 53.6 102.9 1.15 89.1 0.03 Example 4 53.7 102.1 1.17 89.4 0.04 Example 5 54.0 102.5 1.14 89.2 0.03 Comparative Example 1 36.8 81.2 1.82 88.9 0.07 Comparative Example 2 35.2 82.6 1.79 72.3 0.07

[0096] When the test temperature is 60±2°C, the load is 20N, and the holding time is 24h, the indentation diameter can reflect the heat resistance of the material. The larger the indentation diameter, the worse the heat resistance. The samples are tested for aging resistance. The better the tensile retention rate, the better the aging resistance. The samples are tested for damping performance. The lower the loss factor, the lower the damping of the material. Therefore, the test results in Table 1 show that by using the methods of Examples 1-5, PVC-U electrical conduits with low damping, excellent mechanical properties, thermal stability, and aging resistance can be prepared. A comparison between Comparative Example 1 and Examples 1-5 shows that the addition of the epoxy compound can effectively improve the mechanical properties and thermal stability of the electrical conduits while also reducing the damping effect of the material. A comparison between Comparative Example 2 and Examples 1-5 shows that the addition of the composite stabilizer can effectively improve the mechanical properties, thermal stability, and aging resistance of the electrical conduits while also reducing the damping effect of the material.

[0097] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0098] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. Low damping PVC-U electrical conduit, characterized by: The invention comprises the following components in parts by weight: 70-80 parts of PVC resin, 30-42 parts of light calcium carbonate, 8-15 parts of ethylene-vinyl acetate copolymer, 0.5-1 part of vinyl bisstearamide, 3-6 parts of epoxy compound and 4-7 parts of composite stabilizer. The epoxy compound is prepared by taking ethyl benzoylacetate, 2-(trimethylsilyl)phenyl trifluoromethanesulfonate, p-toluenesulfonyl azide, p-aminophenol, p-toluenesulfonyl chloride, iodophenyl diacetic acid and rhodium acetate dimer as raw materials, and the composite stabilizer is prepared by taking 2-(2-aminoethoxy)ethanol, 4-fluorophenol and xylene diisocyanate as raw materials.

2. The low-damping PVC-U electrical bushing according to claim 1, characterized in that: The preparation method of the epoxy composite comprises the following steps: Q1: Ethyl benzoyl acetate and 2-(trimethylsilyl)phenyl trifluoromethanesulfonate were added to a container, acetonitrile was added under a nitrogen atmosphere, and cesium fluoride was then slowly added. The reaction was refluxed. After the reaction was completed, the mixture was cooled, extracted, washed, dried, filtered under reduced pressure, and purified to obtain compound 1. Under a nitrogen atmosphere, compound 1 was added to acetonitrile, and p-toluenesulfonyl azide was then added and stirred. Subsequently, diazabicyclic was added dropwise, stirred at room temperature, and purified to obtain compound 2. Q2: p-Aminophenol and dichloromethane were added to a container, pyridine was added dropwise, p-toluenesulfonyl chloride was added to dichloromethane, stirred to dissolve, and then slowly added dropwise to the container. After the addition was complete, the mixture was stirred at room temperature for reaction. After the reaction was completed, the mixture was extracted, dried, evaporated under reduced pressure, and purified to obtain compound 3. Compound 3 and dichloromethane were added to a container, iodophenyldiacetic acid was slowly added under ice bath, stirred for reaction, extracted, dried, evaporated under reduced pressure, and recrystallized to obtain compound 4. Q3: Add compound 4, dimerized rhodium acetate and propargyl alcohol to a container, add chloroform under nitrogen environment, stir at room temperature, add compound 2 to chloroform, stir to dissolve, add dropwise to the container, stir to react, and after the reaction is completed, purify to obtain an epoxy complex.

3. The low-damping PVC-U electrical bushing according to claim 2, characterized in that: In Q1, the molar ratio of ethyl benzoylacetate, 2-(trimethylsilyl)phenyltrifluoromethanesulfonate and cesium fluoride is (1-2):(1.5-2.5):(2.5-4.3); the molar ratio of compound 1, p-toluenesulfonyl azide and diazabicycle is (1-1.5):(1.5-2.2):(1.5-2.3).

4. The low-damping PVC-U electrical bushing according to claim 2, characterized in that: In Q2, the usage ratio of p-aminophenol, pyridine and p-toluenesulfonyl chloride is (1-1.5) g: (2.9-3.5) mL: (2.1-2.8) g; the usage ratio of compound 3, dichloromethane and iodophenyldiacetic acid is (2-2.5) g: (30-45) mL: (4.9-6.2) g.

5. The low-damping PVC-U electrical bushing according to claim 2, characterized in that: In Q3, the molar ratio of compound 4, dimerized rhodium acetate, propargyl alcohol and compound 2 is (0.2-0.28): (0.05-0.09): (0.1-0.12): (0.2-0.29).

6. The low-damping PVC-U electrical bushing according to claim 1, characterized in that: The preparation method of the composite stabilizer comprises the following steps: S1: Add 2-(2-aminoethoxy)ethanol and formaldehyde aqueous solution to a container containing 1,4-dioxane, stir in an ice bath to react, then add 4-fluorophenol, heat and stir under reflux to react, cool, distill under reduced pressure, dissolve, wash, and dry in vacuo to obtain organic compound a; S2: Add organic matter a to a container containing 1,4-dioxane, then add dibutyltin dilaurate, stir under nitrogen environment, then add dimethylbenzene diisocyanate, heat and reflux to react, after the reaction is completed, distill under reduced pressure, dissolve, wash, vacuum dry, and purify to obtain a composite stabilizer.

7. The low-damping PVC-U electrical bushing according to claim 6, characterized in that: In the S1, the usage ratio of 2-(2-aminoethoxy)ethanol, formaldehyde aqueous solution and 4-fluorophenol is (6.92-10.56) g: (9.2-10.7) mL: (6.72-10.08) g.

8. The low-damping PVC-U electrical bushing according to claim 6, characterized in that: In the S2, the usage ratio of organic matter a, 1,4-dioxane, dibutyltin dilaurate and ditoluene diisocyanate is (4.5-5.6) g: (30-45) mL: (0.2-0.25) g: (2-3.2) mL.

9. The processing technology of low-damping PVC-U electrical casing according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Add PVC resin, light calcium carbonate, epoxy compound and composite stabilizer into a container, mix, and preheat to obtain a mixture; Step 2: The mixture is heated, and then ethylene-vinyl acetate copolymer is added, and the mixing is continued. Then, vinyl bisstearamide is added, and after mixing evenly, cold mixing, extrusion, and shaping are performed to obtain a low-damping PVC-U electrical conduit.

10. The processing technology of low-damping PVC-U electrical casing according to claim 9, characterized in that: In the step 1, the preheating temperature is 80-90°C; in the step 2, the heating treatment temperature is 110-120°C, and the continuous mixing temperature is 120-130°C.

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