Wire and cable coating process

Abstract

The invention belongs to the technical field of wire and cable production, and discloses a wire and cable coating process which comprises the following steps: S1, conductor treatment: selecting a conductor, and performing micro-nano roughening treatment on the surface of the conductor; s2, preparing an insulating material: selecting an insulating base material; by increasing the contact area between the conductor and the coating material (such as the insulating layer and the sheath), the physical binding force, namely the adhesive force, between the conductor and the coating material is improved, and the good adhesive force can ensure that the problem that the insulating layer falls off or the sheath cracks does not easily occur in the use process of the electric wire and cable, so that the service life of the electric wire and cable is prolonged. The reliability and the service life of the wire cable are improved; the roughening treatment also affects the electric field distribution on the surface of the conductor, the phenomenon of electric field concentration is reduced, the risk of insulation breakdown caused by electric field concentration is reduced, and meanwhile, the rough surface structure is beneficial to increasing the contact resistance between the conductor and the coating material, reducing current leakage and further improving the electrical performance of the electric wire and cable.

Description

Technical Field

[0001] The invention belongs to the technical field of wire and cable production, and specifically relates to a wire and cable coating process. Background Art

[0002] There are five major categories of wires and cables: power cables, bare wires, communication cables and optical cables, winding wires, and wires and cables for electrical equipment. They are essential basic materials for transmitting electric energy, transmitting information, and manufacturing various motors, electrical appliances, and instruments. They are essential basic products in the future electrification and information society. For the production and preparation of wires and cables, it is usually necessary to complete the coating process, and the coating process is used to complete the processing and preparation of finished wires and cables.

[0003] The wire and cable coating process in the prior art is limited by the smoothness of the conductor surface during the extrusion coating process. When the extruded insulating sleeve is attached and coated, the contact force between the actual conductor surface and the extruded insulating sleeve is limited due to the influence of the moving conductor, resulting in insufficient adhesion in some cases, causing the insulating sleeve to be thin on some conductor surfaces, resulting in uneven outer insulating sleeves, which greatly reduces the actual production quality and poor use effect. Summary of the invention

[0004] The object of the present invention is to provide a wire and cable coating process to solve the problems raised in the above background technology.

[0005] In order to achieve the above object, the present invention provides the following technical solution: a wire and cable coating process, comprising the following steps:

[0006] S1. Conductor treatment: Select a conductor and perform micro-nano-level roughening treatment on the conductor surface;

[0007] S2. Preparation of insulating materials: Select insulating substrates, and distinguish between composite improved substrate materials and externally treated materials. Use multi-layer co-extrusion technology to independently heat and melt the composite improved substrate materials and externally treated materials.

[0008] S3, extrusion coating treatment: an extruder is used to extrude the molten material, and a double-layer co-extrusion technology is used to extrude the composite improved substrate material and the external treatment material in layers to form a double-layer insulation layer. During the extrusion process, the treated conductor is continuously introduced, the conductor moves in the molten insulation material, and the insulation material is coated on the surface of the conductor;

[0009] S4. Cooling and shaping: With the assistance of ultrasonic vibration, the coated cable is treated by ultrasonic cavitation effect and micro jet, and after treatment, it is completely cooled and solidified by the external cooling system.

[0010] Preferably, the micro-nanoscale roughening treatment in S1 includes one or any of sandblasting, laser treatment and plasma treatment. After the treatment, a roughness measuring instrument is used to detect and evaluate the roughness of the conductor surface. The roughness after the micro-nanoscale roughening treatment is controlled to be 45-80nm.

[0011] Preferably, the conductor is cleaned before the plasma treatment. The plasma treatment equipment includes: a plasma cleaner and a plasma etcher. The working gas for the plasma treatment is argon. The argon is ionized into ionospheric plasma by applying high-frequency electric fields and microwaves and other excitation methods. The plasma treatment time for each group of conductors is 18-30 minutes.

[0012] Preferably, in S2, the composite improved substrate includes environmentally friendly polymer materials, cross-linked polyethylene and nano-composite materials, and the external treatment materials include self-healing materials and heat shrinkable materials.

[0013] Preferably, the environmentally friendly polymer material is polylactic acid (PLA), the nanocomposite material is nanosilicon, the self-healing material is a microcapsule polymer, and the heat shrinkable material is a polyimide film.

[0014] Preferably, in S3, the double-layer co-extrusion technology simultaneously extrude the composite improved substrate and the external treatment material in a single extrusion process, and the double-layer co-machine technology is an extruder with two independent extrusion channels, which are respectively used to extrude the composite improved substrate material and the external treatment material.

[0015] Preferably, in S3, the extrusion temperature is 150° C.-300° C., the extrusion pressure is 9 MPa-25 MPa, and the screw speed is 34 rpm-68 rpm.

[0016] Preferably, in S4, the ultrasonic vibration assist is: the ultrasonic oscillator converts the mechanical vibration into ultrasonic vibration, and transmits the ultrasonic wave to the surface of the cable sheath through the coupling part. The ultrasonic wave can produce violent cavitation effect and microjets during the transmission process, change the physical properties of the cable sheath, and enhance the bonding force between the sheath and the cable core.

[0017] Preferably, in S4, the cable is placed in an ultrasonic vibration device, and the ultrasonic oscillator converts the mechanical vibration into ultrasonic vibration and transmits it to the surface of the cable sheath. Under the action of the ultrasonic vibration, the tiny bubbles in the cooling medium begin to vibrate, grow and gather energy, and when the energy reaches a certain level, the bubbles collapse rapidly and release microjets to impact the cable sheath.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. The present invention forms a micro-nano-scale rough structure on the surface of the conductor to increase the contact area between the conductor and the coating material (such as an insulating layer, a sheath, etc.), thereby improving the physical bonding force between them, that is, the adhesion. Good adhesion can ensure that the wires and cables are not prone to problems such as insulation layer shedding or sheath cracking during use, thereby improving the reliability and service life of the wires and cables; the roughening treatment also affects the electric field distribution on the conductor surface, helps to reduce the electric field concentration phenomenon, thereby reducing the risk of insulation breakdown caused by electric field concentration. At the same time, the rough surface structure helps to increase the contact resistance between the conductor and the coating material, reduce current leakage, and further improve the electrical performance of the wires and cables.

[0020] 2. The present invention reduces the production steps and material change time through double-layer co-extrusion technology, and significantly improves production efficiency; the composite improved substrate can provide the mechanical strength, electrical insulation and heat resistance required for wires and cables, while the external treatment material can provide an additional protective layer, such as wear resistance, anti-aging, flame retardant and other properties. Through the double-layer co-extrusion technology, the two materials can be tightly combined together to form a coating layer with excellent comprehensive performance; compared with the traditional multi-step coating process, the double-layer co-extrusion technology reduces material and energy consumption and reduces production costs; since the double-layer co-extrusion technology can achieve uniform combination of two materials in a single process, it can avoid interface defects and stratification problems caused by multi-layer coating, thereby improving the overall quality and reliability of the product. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0022] The embodiment of the present invention provides a wire and cable coating process, comprising the following steps:

[0023] S1. Conductor treatment: Select a conductor and perform micro-nano-level roughening treatment on the conductor surface;

[0024] S2. Preparation of insulation materials: Select insulation substrates, and distinguish between composite improved substrate materials and external treatment materials. Use multi-layer co-extrusion technology to independently heat and melt the composite improved substrate materials and external treatment materials.

[0025] S3, extrusion coating treatment: an extruder is used to extrude the molten material, and a double-layer co-extrusion technology is used to extrude the composite improved substrate material and the external treatment material in layers to form a double-layer insulation layer. During the extrusion process, the treated conductor is continuously introduced, the conductor moves in the molten insulation material, and the insulation material is coated on the surface of the conductor;

[0026] S4. Cooling and shaping: With the assistance of ultrasonic vibration, the coated cable is treated by ultrasonic cavitation effect and micro jet, and after treatment, it is completely cooled and solidified by the external cooling system.

[0027] Among them, the micro-nanoscale roughening treatment in S1 includes one or any of sandblasting, laser treatment and plasma treatment. After the treatment, the roughness of the conductor surface is detected and evaluated by a roughness measuring instrument. The roughness after the micro-nanoscale roughening treatment is controlled at 45-80nm. The conductor is cleaned before the plasma treatment. The plasma treatment equipment includes: a plasma cleaner and a plasma etcher. The working gas of the plasma treatment is argon. The argon ionospheric plasma is formed by applying a high-frequency electric field and microwave excitation. The plasma treatment time of each group of conductors is 18-30 minutes.

[0028] After the conductor surface is sandblasted, laser treated or plasma treated, a micro-nano-scale rough structure will be formed, which increases the contact area between the conductor and the coating material (such as the insulation layer, sheath, etc.), thereby improving the physical bonding force between them, that is, the adhesion. Good adhesion can ensure that the insulation layer of the wire and cable is not prone to fall off or the sheath cracks during use, thereby improving the reliability and service life of the wire and cable;

[0029] Roughening treatment also affects the electric field distribution on the conductor surface, which helps to reduce the electric field concentration phenomenon, thereby reducing the risk of insulation breakdown caused by electric field concentration. At the same time, the rough surface structure helps to increase the contact resistance between the conductor and the coating material, reduce current leakage, and further improve the electrical performance of wires and cables.

[0030] By controlling the roughness within the range of 45-80nm, it can be ensured that the adhesion is improved without damaging other properties of wires and cables (such as mechanical strength, wear resistance, etc.) due to excessive roughness.

[0031] For plasma treatment processes:

[0032] By cleaning the conductor before plasma treatment, pollutants such as grease and oxides on the conductor surface can be removed, providing a clean surface for subsequent plasma treatment. The clean surface is conducive to the uniform distribution and effective action of ions during plasma treatment, thereby improving the treatment effect. During the plasma treatment, argon gas is ionized into ions by applying high-frequency electric fields and microwaves and other excitation methods. These ions etch and activate the conductor surface, and the etching effect can further increase the roughness of the conductor surface and improve the adhesion with the coating material; the activation effect helps to improve the chemical properties of the conductor surface and improve its compatibility with the coating material.

[0033] Among them, the composite improved substrate includes environmentally friendly polymer materials, cross-linked polyethylene and nano-composite materials, and the external treatment materials include self-healing materials and heat-shrinkable materials. The environmentally friendly polymer material is polylactic acid (PLA), the nano-composite material is nano-silicon, the self-healing material is microcapsule polymer, and the heat-shrinkable material is polyimide film.

[0034] Polylactic acid (PLA) is a bio-based, degradable polymer material. As a coating material for wires and cables, it can significantly reduce environmental pollution and meet the requirements of sustainable development. PLA has certain mechanical strength and toughness, which can meet the basic needs of wire and cable coating. Its good processing performance makes it easy to form and process in the manufacturing process of wires and cables. Cross-linked polyethylene has high heat resistance and can maintain stable physical and chemical properties in high temperature environments, thereby ensuring the safe use of wires and cables under high temperature conditions. Cross-linked polyethylene has excellent electrical insulation properties and can effectively prevent electrical faults such as current leakage and short circuits. The addition of nano-silicon can significantly improve the mechanical strength, wear resistance and heat resistance of the polymer substrate, making the coating of wires and cables more durable. By using a composite modified substrate, the mechanical strength of the wire and cable coating, including tensile strength, tear strength and wear resistance, is significantly improved, making it less likely to be damaged when subjected to external forces, thereby improving its service life and safety.

[0035] The polymer self-healing material of the microcapsule can automatically repair the cracks through the repair agent released from the microcapsule when tiny cracks or damage appear in the sheath of the wire and cable, thereby extending the service life of the wire and cable. The self-repair function can timely detect and repair potential safety hazards of the wire and cable, and reduce the occurrence of electrical failures and safety accidents caused by damage to the sheath; the polyimide film has good heat shrinkage properties and can fit tightly to the surface of the wire and cable after heating to form a tight protective layer. The polyimide film has excellent electrical insulation properties and can effectively prevent the occurrence of electrical failures such as current leakage and short circuit. Its good weather resistance and chemical stability enable the wire and cable to maintain stable performance even in harsh environments, thereby making the external processing materials have higher performance and safety.

[0036] Among them, the double-layer co-extrusion technology simultaneously extrudes the composite improved substrate and external treatment materials in a single extrusion process. The double-layer co-machine technology is an extruder with two independent extrusion channels, which are used to extrude the composite improved substrate material and the external treatment material respectively. The extrusion temperature is 150℃-300℃, the extrusion pressure is 9MPa-to 25MPa, and the screw speed is 34rpm-68rpm.

[0037] Through double-layer co-extrusion technology, double-layer co-extrusion technology allows two materials to be extruded at the same time, thereby reducing production steps and material change time, and significantly improving production efficiency; the composite improved substrate can provide the mechanical strength, electrical insulation and heat resistance required for wires and cables, while the external treatment material can provide an additional protective layer, such as wear resistance, anti-aging, flame retardant and other properties. Through double-layer co-extrusion technology, the two materials can be closely combined together to form a coating layer with excellent comprehensive performance; compared with traditional multi-step coating processes, double-layer co-extrusion technology reduces material and energy consumption and reduces production costs; since double-layer co-extrusion technology can achieve uniform combination of two materials in a single process, it can avoid interface defects and stratification problems caused by multi-layer coating, thereby improving the overall quality and reliability of the product.

[0038] Among them, ultrasonic vibration assistance is: the ultrasonic oscillator converts mechanical vibration into ultrasonic vibration, and transmits the ultrasonic wave to the surface of the cable sheath through the coupling. The ultrasonic wave can produce violent cavitation effect and micro jets during the transmission process, change the physical properties of the cable sheath, and enhance the bonding force between the sheath and the cable core. The cable is placed in an ultrasonic vibration device, and the ultrasonic oscillator converts mechanical vibration into ultrasonic vibration and transmits it to the surface of the cable sheath. Under the action of ultrasonic vibration, the tiny bubbles in the cooling medium begin to vibrate, grow and gather energy, and when the energy reaches a certain level, the bubbles collapse sharply and release micro jets to impact the cable sheath.

[0039] Ultrasonic waves can produce a violent cavitation effect during transmission. The cavitation effect refers to the process in which tiny bubbles in the liquid vibrate, grow and gather energy under the action of ultrasonic waves. When the energy reaches a certain level, the bubbles collapse sharply and release energy. The energy release will produce a strong micro-jets, which impact the cable coating.

[0040] The specific effects are: Ultrasonic vibration assisted technology can significantly improve the bonding strength between the cable coating and the cable core wire. Through the cavitation effect and the impact of microjets, the physical properties of the coating surface are improved, and the contact area and contact tightness with the core wire are increased, thereby improving the bonding strength; and ultrasonic vibration assisted technology can improve the uniformity and density of the coating, reduce the generation of bubbles and defects, and improve the overall quality and reliability of wires and cables.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wire and cable coating process, characterized in that: The following steps are involved: S1. Conductor treatment: Select a conductor and perform micro-nano-level roughening treatment on the conductor surface; S2. Preparation of insulating materials: Select insulating substrates, and distinguish between composite improved substrate materials and externally treated materials. Use multi-layer co-extrusion technology to independently heat and melt the composite improved substrate materials and externally treated materials. S3, extrusion coating treatment: an extruder is used to extrude the molten material, and a double-layer co-extrusion technology is used to extrude the composite improved substrate material and the external treatment material in layers to form a double-layer insulation layer. During the extrusion process, the treated conductor is continuously introduced, the conductor moves in the molten insulation material, and the insulation material is coated on the surface of the conductor; S4. Cooling and shaping: With the assistance of ultrasonic vibration, the coated cable is treated by ultrasonic cavitation effect and micro jet, and after treatment, it is completely cooled and solidified by the external cooling system.

2. A wire and cable coating process according to claim 1, characterized in that: The micro-nano roughening treatment in S1 includes one or any of sandblasting, laser treatment and plasma treatment. After the treatment, a roughness measuring instrument is used to detect and evaluate the roughness of the conductor surface. The roughness after the micro-nano roughening treatment is controlled to be 45-80nm.

3. A wire and cable coating process according to claim 2, characterized in that: The conductor is cleaned before the plasma treatment. The plasma treatment equipment includes: a plasma cleaner and a plasma etcher. The working gas for the plasma treatment is argon. The argon is ionized into ionospheric plasma by applying high-frequency electric fields and microwaves. The plasma treatment time for each group of conductors is 18-30 minutes.

4. A wire and cable coating process according to claim 1, characterized in that: In S2, the composite improved substrate includes environmentally friendly polymer materials, cross-linked polyethylene and nano-composite materials, and the external treatment materials include self-healing materials and heat shrinkable materials.

5. A wire and cable coating process according to claim 4, characterized in that: The environmentally friendly polymer material is polylactic acid (PLA), the nano-composite material is nano-silicon, the self-repairing material is a microcapsule polymer, and the heat shrinkable material is a polyimide film.

6. A wire and cable coating process according to claim 1, characterized in that: In S3, the double-layer co-extrusion technology simultaneously extrude the composite improved substrate and the external treatment material in a single extrusion process. The double-layer co-machine technology is an extruder with two independent extrusion channels, which are respectively used to extrude the composite improved substrate material and the external treatment material.

7. A wire and cable coating process according to claim 6, characterized in that: In S3, the extrusion temperature is 150° C.-300° C., the extrusion pressure is 9 MPa-25 MPa, and the screw speed is 34 rpm-68 rpm.

8. The wire and cable coating process according to claim 1, characterized in that: In S4, ultrasonic vibration assistance is: the ultrasonic oscillator converts mechanical vibration into ultrasonic vibration, and transmits the ultrasonic wave to the surface of the cable sheath through the coupling member. The ultrasonic wave can produce violent cavitation effect and micro jets during the transmission process, change the physical properties of the cable sheath, and enhance the bonding force between the sheath and the cable core.

9. A wire and cable coating process according to claim 8, characterized in that: In S4, the cable is placed in an ultrasonic vibration device, and the ultrasonic oscillator converts mechanical vibration into ultrasonic vibration and transmits it to the surface of the cable sheath. Under the action of ultrasonic vibration, tiny bubbles in the cooling medium begin to vibrate, grow and gather energy, and when the energy reaches a certain level, the bubbles collapse rapidly and release microjets to impact the cable sheath.