Ammonia-resistant PVC insulated automobile wire and preparation method thereof

Abstract

The application provides a PVC insulated automobile wire resistant to ammonia and a preparation method thereof. The wire comprises a conductor and an insulating layer coated on the outer layer of the conductor. The insulating layer is made of ammonia-resistant PVC material. The ammonia-resistant PVC material comprises PVC resin, ammonia-resistant type trimellitate plasticizer, epoxy soybean oil, calcium-zinc composite stabilizer, antioxidant, hydrolysis-resistant type lubricant, ammonia-resistant special hydrolysis-resistant auxiliary agent and inorganic filler. The manufacturing method comprises the steps of conductor annealing, insulating material mixing, extrusion coating, traction wire collecting and detection. The wire of the application is not cracked and brittle in a limited contact with ammonia and ammonia water solution environment, has high insulating performance and mechanical performance retention rate, meets the requirements of GB / T 25085.3 standard, and is controllable in cost and easy to mass produce.

Description

Technical Field

[0001] This invention relates to the field of automotive wire and cable technology, specifically to an ammonia-resistant PVC insulated automotive wire and its preparation method. Background Technology

[0002] With the rapid development of the new energy vehicle industry and the diversification of its application scenarios, emerging application areas such as green ammonia fuel vehicles and port special operation vehicles are increasing. In these application scenarios, automotive wiring may face short-term, limited contact with ammonia gas, ammonia vapor, or weakly alkaline ammonia solution during actual use.

[0003] However, due to their inherent material properties, traditional polyvinyl chloride (PVC) insulated automotive wires exhibit significant performance defects in environments with ammonia exposure risks. Firstly, the PVC resin molecular backbone contains numerous C-Cl bonds, which readily undergo dehydrochlorination in alkaline environments. This reaction leads to molecular chain breakage, causing insulation embrittlement and cracking, resulting in a sharp deterioration of its electrical insulation performance. Secondly, ester plasticizers commonly used in traditional PVC insulation (such as dioctyl phthalate (DOP) and diisononyl phthalate (DINP)) are easily extracted by ammonia and undergo hydrolysis (often compared to saponification). The loss and decomposition of plasticizers directly damage the plasticity of PVC materials, leading to increased insulation hardness, loss of toughness, and increased brittleness, ultimately significantly shortening the wire's lifespan.

[0004] Currently, conventional automotive wiring designs are not specifically optimized for the limited or non-continuous ammonia exposure environments mentioned above. While materials such as fluoroplastics and cross-linked polyethylene (XLPE) possess excellent ammonia resistance, their high manufacturing costs make them difficult to widely apply in cost-sensitive mid-to-low-end vehicle models and auxiliary or non-critical circuit systems. Furthermore, GB / T 25085.3, the core standard for automotive wiring, primarily specifies requirements and test methods for wires in terms of heat resistance, oil resistance, liquid resistance (such as fuel and coolant), mechanical properties, and electrical properties, but it does not include test methods and judgment indicators for tolerance to ammonia exposure environments. This lack of a standard leaves the product design, performance evaluation, and production quality control of ammonia-resistant PVC insulated automotive wiring without a direct and effective basis.

[0005] Therefore, developing a PVC-insulated automotive wire that is simple in structure, cost-controllable, meets the basic performance requirements of GB / T 25085.3 standard, and can effectively withstand limited contact with ammonia gas, ammonia vapor, and weak ammonia solution has become an important technical problem that urgently needs to be solved in the field of automotive wire technology. It is of great practical significance for promoting the safe and reliable application of new energy vehicles in a wider range of scenarios. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an ammonia-resistant PVC insulated automotive wire and its preparation method. While achieving a simple structure, controllable cost, and meeting the requirements of GB / T 25085.3 standard, it can withstand limited contact with ammonia gas, ammonia vapor and weak ammonia solution, avoiding failure phenomena such as embrittlement, cracking and insulation degradation.

[0007] This invention is implemented as follows: An ammonia-resistant PVC-insulated automotive wire includes a conductor and an insulating layer covering the conductor, the insulating layer being made of an ammonia-resistant PVC material comprising the following components in parts by weight: 100 parts of PVC resin; 35-45 parts of ammonia-resistant trimellitic ester plasticizer; 3-5 parts of epoxidized soybean oil; Calcium-zinc compound stabilizer 2.5–3.5 parts; Antioxidant 0.3-0.5 parts; Hydrolysis-resistant lubricant, 0.8–1.2 parts; Ammonia-resistant hydrolysis-resistant additive, 1.0–2.0 parts; 15–25 parts of inorganic filler.

[0008] Furthermore, the conductor is a tin-plated copper conductor, and the tin layer thickness of the tin-plated copper conductor is ≥8μm.

[0009] Furthermore, the thickness of the insulating layer is 0.3 to 1.0 mm.

[0010] Furthermore, it also includes an outer sheath layer covering the outside of the insulation layer, the outer sheath layer being made of the ammonia-resistant PVC material or PP material, and the sheath thickness being 0.2 to 0.5 mm.

[0011] Furthermore, the hydrolysis-resistant lubricant is a compound system of calcium stearate and paraffin, the ammonia-resistant hydrolysis-resistant additive is a polycarbodiimide additive, and the inorganic filler is light calcium carbonate.

[0012] A method for manufacturing an ammonia-resistant PVC insulated automotive wire specifically includes the following steps: S1: Conductor pretreatment: The tin-plated copper wire is annealed at a temperature of 400-500℃. S2: Insulation material preparation: Weigh each component of the ammonia-resistant PVC material according to the stated weight proportions, put them into a high-speed mixer, and mix at 100-120°C for 10-15 minutes to obtain the ammonia-resistant PVC material; S3: Insulation layer extrusion: The pretreated conductor is fed into an extruder, and the ammonia-resistant PVC material is extruded onto the outside of the conductor using an extrusion process. The extrusion temperature is controlled at 160-180℃. S4: Traction and winding: The traction machine pulls the yarn, and the traction speed is controlled to match the extrusion speed to form a coil.

[0013] Furthermore, it also includes step S5: finished product inspection: testing the electrical performance, mechanical performance, heat resistance, oil resistance and ammonia resistance of the wire.

[0014] Furthermore, in step S3, the conductor is preheated before extrusion, and the preheating temperature is 80-100°C.

[0015] Furthermore, in step S3, the extrusion speed is 1000-1200 m / min.

[0016] The advantages of the ammonia-resistant PVC insulated automotive wire provided by this invention are: First, excellent ammonia resistance: under limited exposure to ammonia gas (40℃, 5000ppm, 96h) and ammonia solution (mass fraction ≤5%, room temperature, 72h), it does not crack, whiten, harden, or powder, and maintains good flexibility.

[0017] Second, the insulation performance is stable: after the ammonia resistance test, the insulation resistance retention rate is ≥90%, and the dielectric strength does not decrease significantly, which meets the electrical performance requirements of GB / T 25085.3 standard.

[0018] Third, reliable mechanical properties: tensile strength retention rate > 85%, elongation at break retention rate > 80%, good bending performance, suitable for bending, vibration and other working conditions in automotive wiring process.

[0019] Fourth, cost is controllable: using conventional PVC resin as the base material, the ammonia resistance is improved only through formula optimization, and the cost is close to that of ordinary PVC insulated automotive wires, and far lower than that of ammonia-resistant materials such as fluoroplastics and XLPE wires.

[0020] The manufacturing method provided by this invention is fully compatible with existing PVC insulated automotive wire production lines, requiring no additional equipment investment and enabling rapid large-scale production. By controlling the extrusion speed at 1000–1200 m / min and supplementing it with conductor preheating at 80–100°C, the thermal stress between the insulation layer and the conductor can be effectively eliminated, resulting in more uniform plasticization and lower internal stress of the PVC material during extrusion. This significantly improves the elongation at break and tensile strength qualification rate of the insulation layer. Furthermore, this method has a wide process window (extrusion temperature 160–180°C), good operational stability, and high yield, making it suitable for continuous industrial production. Detailed Implementation Example 1

[0021] This embodiment provides an ammonia-resistant PVC insulated automotive wire, which includes, from the inside out, a conductor, an insulation layer, and an outer sheath layer. The conductor is a tin-plated copper conductor, and the tin layer thickness of the tin-plated copper conductor is ≥8μm. The insulation layer is made of ammonia-resistant PVC material with a thickness of 0.3-1.0mm. The outer sheath layer is made of ammonia-resistant PVC material or PP material with a sheath thickness of 0.2-0.5mm. The ammonia-resistant PVC material contains the following components in parts by weight: 100 parts of PVC resin; 35-45 parts of ammonia-resistant trimellitic ester plasticizer; 3-5 parts of epoxidized soybean oil; Calcium-zinc compound stabilizer 2.5–3.5 parts; Antioxidant 0.3-0.5 parts; Hydrolysis-resistant lubricant, 0.8–1.2 parts; Ammonia-resistant hydrolysis-resistant additive, 1.0–2.0 parts; 15–25 parts of inorganic filler.

[0022] The hydrolysis-resistant lubricant is a compound system of calcium stearate and paraffin wax, used to improve the material's processing fluidity, while also possessing hydrolysis and ammonia resistance properties, preventing lubricant migration that could lead to a decline in material performance. The ammonia-resistant hydrolysis-resistant additive is a polycarbodiimide additive, used to improve the material's resistance to ammonia solutions and reduce the erosion of PVC molecular chains by ammonia molecules. The inorganic filler is light calcium carbonate, used to improve the mechanical strength and dimensional stability of the insulation layer, reduce production costs, and without affecting the material's ammonia resistance and insulation properties.

[0023] The advantages of the ammonia-resistant PVC insulated automotive wire provided in this embodiment are: First, excellent ammonia resistance: under limited exposure to ammonia gas (40℃, 5000ppm, 96h) and ammonia solution (mass fraction ≤5%, room temperature, 72h), it does not crack, whiten, harden, or powder, and maintains good flexibility.

[0024] Second, the insulation performance is stable: after the ammonia resistance test, the insulation resistance retention rate is ≥90%, and the dielectric strength does not decrease significantly, which meets the electrical performance requirements of GB / T 25085.3 standard.

[0025] Third, reliable mechanical properties: tensile strength retention rate > 85%, elongation at break retention rate > 80%, good bending performance, suitable for bending, vibration and other working conditions in automotive wiring process.

[0026] Fourth, cost is controllable: using conventional PVC resin as the base material, the ammonia resistance is improved only through formula optimization, and the cost is close to that of ordinary PVC insulated automotive wires, and far lower than that of ammonia-resistant materials such as fluoroplastics and XLPE wires. Example 2

[0027] This embodiment provides a method for manufacturing ammonia-resistant PVC insulated automotive wire, including the following steps: S1: Conductor pretreatment: Anneal the bare copper wire or tin-plated copper wire at a temperature of 400-500℃ to ensure the conductor's flexibility. S2: Insulation material preparation: Weigh out each component of any of the ammonia-resistant PVC materials provided in Table 1 (Examples 1 to 4) according to the weight proportions, put them into a high-speed mixer, and mix at 100-120°C for 10-15 minutes to obtain the ammonia-resistant PVC material. S3: Insulation layer extrusion: After the conductor is preheated to 80℃~100℃, it is fed into the extruder. The ammonia-resistant PVC material is extruded onto the outside of the conductor using the extrusion process. The extrusion temperature is controlled at 160~180℃ and the extrusion speed is 1000m / min~1200m / min. S4: Traction and take-up: The traction machine pulls the yarn, and the traction speed is controlled to match the extrusion speed to form a coil; S5: Finished product inspection: Test the electrical properties, mechanical properties, heat resistance, oil resistance and ammonia resistance of the wire.

[0028] Table 1: Components (parts by weight) of ammonia-resistant PVC materials

[0029] Comparative Example To demonstrate the inventiveness of this invention, a wire made of conventional PVC cable material is provided as a comparative example. The specific components of the conventional PVC cable material are: 100 parts of PVC resin, 40 parts of DIDP+TOTM compound plasticizer, 5 parts of calcium-zinc stabilizer, 25 parts of light calcium carbonate, 0.5 parts of stearic acid lubricant, and 0.8 parts of antioxidant.

[0030] The ammonia-resistant PVC insulated automotive wires prepared in Preparation Examples 1 to 4 were subjected to ammonia resistance tests (40°C, 5000ppm ammonia, 96h) with the comparative examples. The results are shown in Table 2.

[0031] Table 2: Test Items and Results

[0032] As shown in Table 2, the ammonia-resistant PVC insulated automotive wires prepared by Preparation Examples 1 to 4 showed no cracking or whitening, and the insulation resistance retention rate, tensile strength retention rate, and elongation at break retention rate were significantly improved compared with the comparative examples.

[0033] The manufacturing method provided by this invention is fully compatible with existing PVC insulated automotive wire production lines, requiring no additional equipment investment and enabling rapid large-scale production. By controlling the extrusion speed at 1000–1200 m / min and supplementing it with conductor preheating at 80–100°C, the thermal stress between the insulation layer and the conductor can be effectively eliminated, resulting in more uniform plasticization and lower internal stress of the PVC material during extrusion. This significantly improves the elongation at break and tensile strength qualification rate of the insulation layer. Furthermore, this method has a wide process window (extrusion temperature 160–180°C), good operational stability, and high yield, making it suitable for continuous industrial production.

[0034] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An ammonia-resistant PVC insulated automotive wire, comprising a conductor and an insulating layer covering the conductor, characterized in that: The insulating layer is made of ammonia-resistant PVC material, which comprises the following components in parts by weight: 100 parts of PVC resin; 35-45 parts of ammonia-resistant trimellitic ester plasticizer; 3-5 parts of epoxidized soybean oil; Calcium-zinc compound stabilizer 2.5–3.5 parts; Antioxidant 0.3-0.5 parts; Hydrolysis-resistant lubricant, 0.8–1.2 parts; Ammonia-resistant hydrolysis-resistant additive, 1.0–2.0 parts; 15–25 parts of inorganic filler.

2. The ammonia-resistant PVC insulated automotive wire according to claim 1, characterized in that: The conductor is a tin-plated copper conductor, and the tin layer thickness of the tin-plated copper conductor is ≥8μm.

3. The ammonia-resistant PVC insulated automotive wire according to claim 1, characterized in that: The thickness of the insulating layer is 0.3 to 1.0 mm.

4. The ammonia-resistant PVC insulated automotive wire according to claim 1, characterized in that: It also includes an outer sheath layer covering the outside of the insulation layer, the outer sheath layer being made of the ammonia-resistant PVC material or PP material, and the sheath thickness being 0.2 to 0.5 mm.

5. The ammonia-resistant PVC insulated automotive wire according to claim 1, characterized in that: The hydrolysis-resistant lubricant is a compound system of calcium stearate and paraffin, the ammonia-resistant hydrolysis-resistant additive is a polycarbodiimide additive, and the inorganic filler is light calcium carbonate.

6. A method for manufacturing an ammonia-resistant PVC insulated automotive wire according to any one of claims 1 to 5, characterized in that: Includes the following steps: S1: Conductor pretreatment: The tin-plated copper wire is annealed at a temperature of 400-500℃. S2: Insulation material preparation: Weigh each component of the ammonia-resistant PVC material according to the stated weight proportions, put them into a high-speed mixer, and mix at 100-120°C for 10-15 minutes to obtain the ammonia-resistant PVC material; S3: Insulation layer extrusion: The pretreated conductor is fed into an extruder, and the ammonia-resistant PVC material is extruded onto the outside of the conductor using an extrusion process. The extrusion temperature is controlled at 160-180℃. S4: Traction and winding: The traction machine pulls the yarn, and the traction speed is controlled to match the extrusion speed to form a coil.

7. The method for manufacturing an ammonia-resistant PVC insulated automotive wire according to claim 6, characterized in that: It also includes step S5: Finished product inspection: The electrical performance, mechanical performance, heat resistance, oil resistance and ammonia resistance of the wire are tested.

8. The method for manufacturing an ammonia-resistant PVC insulated automotive wire according to claim 6, characterized in that: In step S3, the conductor is preheated before extrusion, and the preheating temperature is 80-100°C.

9. A method for manufacturing an ammonia-resistant PVC insulated automotive wire according to claim 6, characterized in that: In step S3, the extrusion speed is 1000-1200 m / min.

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