Preparation method of coated silica gel for tinned copper wire

Abstract

The present invention relates to a method for preparing a coated silica gel for a tin-plated copper wire, the method comprising the steps of: providing a conductor comprising providing a conductor comprising a tin-plated copper wire; a silica gel coating layer is manufactured, specifically, the surface of the electric conductor containing the tinned copper wire is coated with a silica gel coating layer, and the silica gel coating layer comprises magnesium hydroxide coated with attapulgite and zirconium phosphate coated with attapulgite; and an outer sleeve layer forming step: forming an outer sleeve layer on the outer surface of the silica gel coating layer, the outer sleeve layer containing a chlorine element, preferably, the outer sleeve layer containing a high-molecular polymer of the chlorine element. According to the manufacturing process and the obtained electric wire composite structure, the stability of electric power transmission and electric signals of the electric wire can be well maintained at the same time.

Description

Technical Field

[0001] This invention relates to a method and process for coating metallic materials. Specifically, this invention relates to a method for preparing a silicone coating for tin-plated copper wires. Background Technology

[0002] With the booming development of the new energy industry, fields such as high-power energy storage, new energy vehicles, and photovoltaic technology have also made significant progress. In the complex field of power supply, it is usually necessary not only to provide a sustainable high-power current, but also to maintain the high-speed and stable transmission of signals. This places higher demands on the heat resistance, insulation, flame retardancy, and electrical stability of cables and wires.

[0003] For example, in automobiles, especially around the engine where it operates at high temperatures, or around the power battery of new energy vehicles, there is a need for wires and cables that are highly flame-retardant, highly insulating, and capable of maintaining good performance for extended periods under high-temperature conditions. This necessitates a coating process for insulating, heat-resistant, and flame-retardant wires. Among various flame retardants, metal oxides, primarily magnesium hydroxide, can play a role in providing high flame retardancy and are widely used as flame retardants in communication wires. However, in wire and cable products where magnesium hydroxide is used as a flame-retardant, heat-insulating, and insulating material, a highly tough and cost-effective outer packaging material is often required. This inevitably leads to the common use of Cl-containing polymer materials as the outermost packaging, such as polyvinyl chloride (PVC).

[0004] However, the inventors discovered that chlorine in materials such as polyvinyl chloride (PVC) can migrate into the interior of electrical wires under high-temperature conditions and prolonged use. These chlorine atoms can also migrate along with plasticizers into the sheathing, insulation, and even the interior of communication wires. While chlorine atoms do not directly cause short circuits or damage, they can combine with metal atoms to absorb moisture and penetrate conductors, leading to undesirable fluctuations in the electrical signals and characteristics of wires and cables. For example, a sudden drop in the resistance of a wire or cable can cause disorder or instability in signal transmission.

[0005] Wires and cables containing flame retardants or insulating components have been extensively researched and explored. For example, Chinese Patent Publication CN111599515A discloses a nitrile insulated and sheathed flexible cable for trolleys and its manufacturing method, including a nitrile insulating sleeve, a sheath, a funnel-shaped plate, and an inner column. The sheath is fitted inside the nitrile insulating sleeve, and the funnel-shaped plate is fitted inside the sheath. This nitrile insulated and sheathed flexible cable for trolleys and its manufacturing method, through the combined use of accessories, combines the sheath on both sides of the nitrile insulating sleeve and forms a sloping groove with a sliding groove inside the sheath, which can be combined with the funnel-shaped plate. The sloping groove engages with the sliding sleeve on the funnel-shaped plate, achieving the purpose of limiting the rotation. This allows the inner column with reinforcing ribs to rotate internally. The filling block in the inner groove limits the movement and ensures the wrapping of the funnel-shaped plate, increasing the torque dissipation ability during rotation and preventing severe breakage of the flexible cable. At the same time, the ribs increase the strength. However, the implementation scheme in this document uses a large amount of chlorine-containing materials as a protective structure, but does not address or consider the problem of fluctuations in the electrical properties of wires and cables caused by improper chlorine penetration, nor does it consider maintaining the mechanical and fire-resistant properties of wires and cables under complex working conditions.

[0006] Therefore, there are still issues in this area that require further development and improvement. Summary of the Invention

[0007] The present invention aims to provide a method for preparing coated silicone (also referred to as coated silicone rubber material in certain implementation scenarios or technical backgrounds) for tin-plated copper wires, as well as related composite structures and products. The composite structure of coated silicone for tin-plated copper wires prepared according to the embodiments of the present invention can well maintain the electrical and mechanical properties of wires and cables, while also possessing good fire and heat resistance.

[0008] A first aspect of the present invention provides a method for preparing a coated silicone for tin-plated copper wires, characterized in that the method comprises the following steps:

[0009] The step of providing a conductor includes providing a conductor comprising tin-plated copper wires;

[0010] The step of fabricating a silicone coating layer includes coating the surface of the conductive body containing tin-plated copper wires with a silicone coating layer, the silicone coating layer comprising magnesium hydroxide coated with attapulgite and zirconium phosphate coated with attapulgite; and

[0011] The step of forming an outer layer includes forming an outer layer on the outer surface of the silicone coating layer, the outer layer containing chlorine, preferably, the outer layer containing a chlorine-containing polymer.

[0012] In a further preferred embodiment, the step of providing the conductor includes:

[0013] Step 1), prepare the copper core conductor; and

[0014] Step 2) Using the copper core conductor as the core, wrap the tin-plated copper wire around it; preferably, the tin-plated copper wire is covered with an insulating material before wrapping the copper core conductor.

[0015] In a further preferred embodiment, the step of fabricating the silicone coating layer includes:

[0016] Step 3) Prepare raw material components including silicone rubber, polyolefin thermoplastic elastomer, styrene-butadiene rubber, polypropylene fiber, magnesium hydroxide coated with attapulgite clay, zirconium phosphate coated with attapulgite clay, and silicone oil.

[0017] First, the prepared silicone rubber, polyolefin thermoplastic elastomer, styrene-butadiene rubber, and polypropylene fiber are placed in a mixer for mixing; then, magnesium hydroxide coated with attapulgite clay, zirconium phosphate coated with attapulgite clay, and silicone oil are added, and a second mixing is performed to obtain the silicone-coated material; and

[0018] The silicone coating layer is applied to the surface of the tin-plated copper wire.

[0019] In a further preferred embodiment, the attapulgite-coated magnesium hydroxide and the attapulgite-coated zirconium phosphate are prepared by the following method:

[0020] Magnesium hydroxide and attapulgite are mixed in a mass ratio of 1:1 to 1:2, and a plasticizing and sealing agent of 5%wt-10%wt of magnesium hydroxide mass is added. The magnesium hydroxide, attapulgite, and plasticizing and sealing agent are mixed in a mixer and then allowed to stand for 10-20 hours to obtain magnesium hydroxide material coated with attapulgite.

[0021] Zirconium phosphate and attapulgite are mixed at a mass ratio of 1:0.5 to 1:1.5, and a plasticizer / sealing agent accounting for 5% wt-10% wt of the zirconium phosphate mass is added. Then, the zirconium phosphate, attapulgite, and plasticizer / sealing agent are mixed in a mixer, and then allowed to stand for 10-20 hours to obtain a zirconium phosphate material coated with attapulgite; and preferably, [the following is a more specific description of the process].

[0022] The plasticizer / clotting agent is diisononyl phthalate (DINP).

[0023] In a further preferred embodiment, the method specifically includes the following steps:

[0024] Step 1) Prepare a copper core conductor;

[0025] Step 2) Using a copper core conductor as the core, wrap around the tin-plated copper wire; wherein the tin-plated copper wire is wrapped with insulating polyester tape on its surface before being wrapped.

[0026] Step 3) Prepare the silicone coating layer: by weight, prepare 20-100 parts of silicone rubber, 20-60 parts of polyolefin thermoplastic elastomer, 2-10 parts of styrene-butadiene rubber, 1-15 parts of polypropylene fiber, 5-20 parts of magnesium hydroxide coated with attapulgite clay, 5-20 parts of zirconium phosphate coated with attapulgite clay, and 1-5 parts of silicone oil as raw material components.

[0027] First, silicone rubber, polyolefin thermoplastic elastomer, styrene-butadiene rubber, and polypropylene fiber are placed in a mixer and heated to 120-160℃ for 5-15 minutes. Then, the temperature is adjusted to 90℃-110℃, and magnesium hydroxide coated with attapulgite clay, zirconium phosphate coated with attapulgite clay, and silicone oil are added and mixed for 1-5 minutes to obtain the silicone coating material. Subsequently, the tin-plated copper wire prepared in step 2) and the silicone coating material are fed into an extrusion device, and the silicone coating is coated onto the surface of the tin-plated copper wire using a co-extrusion process.

[0028] Step 4) Forming the outer layer structure:

[0029] A film or sheet material containing 80-120 parts by weight of polyvinyl chloride (PVC) and 5-15 parts by weight of diisononyl phthalate (DINP) is used to make the outer layer, and then it is wrapped around the outer surface of the tin-plated copper wire containing the silicone coating layer obtained in step 3) above.

[0030] In a further preferred embodiment, the elastic modulus of the silicone coating layer is between 60 MPa and 80 MPa.

[0031] According to a second aspect of the present invention, a composite structure of silicone coating on tin-plated copper wire is provided, wherein the composite structure comprises:

[0032] Copper core conductor;

[0033] Tin-plated copper wire covering the outside of the copper core conductor;

[0034] The silicone coating layer covering the outside of the tin-plated copper wire; and

[0035] A chlorine-containing outer layer covering the outside of the silicone coating layer.

[0036] In an optional embodiment, the silicone coating layer has an elastic modulus between 60 MPa and 80 MPa.

[0037] The technical solution of this invention utilizes a core-shell structure formed by separately coating magnesium hydroxide and zirconium phosphate with attapulgite clay. This structure not only effectively maintains the good and stable electrical properties (conductivity and dielectric properties) of tin-plated copper wire, but also maintains good high-temperature resistance. This makes the wire structure suitable for high-power output current and corresponding control signals under high-temperature conditions, which will be explained in more detail below.

[0038] The technical solutions and advantages of the present invention will be explained and described in more detail below with reference to specific embodiments. It should be understood that the content presented in the specification and specific embodiments is only for the purpose of more clearly illustrating the technical solutions and advantages of the present invention, and does not constitute a limitation on the scope of protection of the present invention. Those skilled in the art can obtain various reasonable modifications based on the disclosure in the specification, and as long as they do not depart from the spirit of the present invention, all modified technical solutions should be understood to be included within the scope of protection of the present invention. Attached Figure Description

[0039] The accompanying drawings are provided to further understand the technical solutions of this disclosure and constitute a part of the specification. They are used together with the specific embodiments of this application to explain the technical solutions of this disclosure and do not constitute a limitation on the technical solutions of this disclosure.

[0040] Figure 1 This is a cross-sectional schematic diagram of a composite wire structure formed by coating tin-plated copper wire with silicone.

[0041] Figure 2 This is a schematic diagram of an application example of the composite wire structure formed by coating tin-plated copper wires with silicone according to the present invention.

[0042] Figure 3 This is a schematic diagram of another application example of the composite wire structure formed by coating tin-plated copper wires with silicone.

[0043] Explanation of reference numerals in the attached figures:

[0044] 100 - Composite wire structure; 101 - Copper core conductor; 102 - Tinned copper wire; 103 - Silicone coating layer; 104 - Outer jacket layer;

[0045] 201-First snap-fit ​​structure; 202-Second snap-fit ​​structure; 203-Snap-fit ​​block; 204-Transfer block interface; 205-Adapter plate; 206-Snap-fit ​​slot; 207-Snap-fit ​​hook. Detailed Implementation

[0046] The invention is described in more detail below to aid in understanding it.

[0047] Before describing the specific implementation scheme, it should be noted that those skilled in the art can select appropriate raw materials based on the teachings and guidance of this disclosure, conduct relevant tests using relevant testing equipment, and obtain corresponding results. For raw materials for which specific manufacturers or methods are not specified, those skilled in the art can select raw materials that meet the corresponding requirements as reaction starting materials based on the disclosure and needs of this specification. The reaction raw materials for the compounds in the process section are derived from the initial products synthesized in the preceding steps of this invention, which is also understandable based on this disclosure.

[0048] Table 1 lists the main raw materials used in this invention and their corresponding acquisition channels or origins. It should be noted that any raw materials not specified in this invention are those that can be obtained by those skilled in the art based on ordinary technical knowledge and existing market products.

[0049] Table 1: Description of the main raw materials used in this invention

[0050] Material / Chemical Name source Remark silicone rubber Shin-Etsu CHN3400 transparent silicone rubber from Japan Polyolefin thermoplastic elastomers Exxon POE Vitamax™ 6202 Polyolefin Elastomer Styrene-butadiene rubber KETEN™ SIS D1117PT thermoplastic styrene-butadiene rubber produced by Guangdong Dongbai Rubber & Plastics Co., Ltd. Polypropylene fiber Polypropylene crack-resistant fiber from Shandong Hongyu Engineering Materials Co., Ltd. <![CDATA[PP fiber, density 0.91 g / cm 3 , equivalent diameter 30 - 35 μm]]> Attapulgite White attapulgite clay supplied by Shijiazhuang Lincheng Minerals <![CDATA[Average density 2.3 g / cm 3 , hardness 7.2 HB, CaO content 23%]]> Magnesium hydroxide Hangzhou Jiupeng New Materials Co., Ltd. Nanoscale, D50 average particle size 35-40nm Zirconium phosphate Hubei Weideli Co., Ltd., Analytical Purity Grade CAS 13772-29-7, average particle size approximately 200 mm. diisononyl phthalate From Merck Sigma-Aldrich. CAS28553-12-0, chemical formula C26H42O4 Tinned copper wire Provided by Shenzhen Haideco Electronics Co., Ltd.

[0051] It should be noted that percentages indicated in the technical solutions, embodiments, and content of the present invention will generally be specifically described. Unless otherwise specified, the percentages refer to mass percentages (wt%) or proportions between mass parts.

[0052] Furthermore, the process and material composition of the present invention may include the components described in the embodiments or technical solutions, as well as other auxiliary components; in addition, in preferred embodiments, the material composition of the present invention may consist only of the described components, without necessarily including other components. For example, the silicone outer covering component may consist only of the components described in the embodiments, without necessarily including other redundant or unnecessary components.

[0053] Example 1

[0054] This embodiment describes a typical process for coating silicone wires with tin-plated copper wires and the method for preparing the corresponding product.

[0055] refer to Figure 1 The diagram shows a cross-sectional structure of a composite wire structure 100 formed by coating tinned copper wire with silicone. The structure includes a copper core conductor 101, braided tinned copper wire 102 surrounding the copper core conductor 101, a silicone coating layer 103 surrounding the tinned copper wire 102, and an outer jacket layer 104 surrounding the silicone coating layer 103.

[0056] This composite wire structure 100 is suitable for transmitting high-power current and can also transmit electrical signals through the tinned copper wire portion. It is suitable for high-power electrical products, such as power / signal cables for new energy vehicles, charging pile cables, high-power photovoltaic equipment, and energy storage devices. The composite structure involved in this invention is not limited to this. In some applications, if high-power current transmission is not required, the copper core conductor 101 can be omitted, and the tinned copper wire 102 can be used directly. In other words, in the tinned copper wire shown below, the composite structure can be formed by using a copper core wire as the inner core and tinned copper wire as the outer layer of the copper core. However, the design scheme of this invention is not limited to this.

[0057] The process of coating tinned copper wires with silicone typically includes the following steps and methods:

[0058] Step 1), prepare copper core conductor 101:

[0059] In this embodiment, to ensure good flexibility and bending performance, the copper core conductor is made of soft round copper wire, such as TR-type soft round copper wire (e.g., soft copper wire conforming to GBT 3953-2009 standard or higher). The outer diameter deviation of a single wire is controlled within ±0.003 mm or less, the resistivity is not greater than 0.020 Ω·mm² / m, and high-toughness copper wire with an elongation of not less than 20% is selected. After the copper conductor is stranded, it can be rounded according to relevant processes to obtain the core of the finished copper wire.

[0060] Step 2) is a process in which a copper core conductor 101 is used as the core and a tin-plated copper wire 102 is wound around the outside.

[0061] Before the braiding process, the tin-plated copper wire 102 is coated with a layer of insulating polyester tape. Figure 1 (Not shown in the image, but using, for example, 3M 1350F polyester electrical tape). The weaving uses tin-plated soft round copper wire, and the pitch is strictly controlled according to the process requirements. The weaving density should not be less than 95%, and the weaving angle should be controlled between 10° and 30°. During the weaving process, ensure that the tin-plated copper wire 102 is tightly wrapped around the copper core conductor 101.

[0062] It should be noted that in other optional embodiments, if the copper core 101 is not required in the composite wire structure, then step 1) can be omitted in this process. At the same time, the tinned copper wire in step 2) does not need to be covered with the insulating polyester tape. Instead, the multi-strand tinned copper wire can be braided by itself or used directly as tinned copper wire (tinned copper wire).

[0063] Step 3), fabricate the silicone coating layer 103. In the following description, unless otherwise specified, the number of parts of each component is calculated according to the "parts by weight" of the material or chemical substance, and the proportions between the components can also be calculated and described according to weight proportions.

[0064] In the typical preparation process of silicone coating layer 103, 50 parts of silicone rubber, 50 parts of TEO polyolefin thermoplastic elastomer, 5 parts of styrene-butadiene rubber, 5 parts of polypropylene fiber, 5 parts of magnesium hydroxide coated with attapulgite, 5 parts of zirconium phosphate coated with attapulgite, and 2 parts of silicone oil are prepared.

[0065] In the preparation process, the prepared silicone rubber, TEO polyolefin thermoplastic elastomer, styrene-butadiene rubber, and polypropylene fiber are first put into a mixer and heated to 160°C for 10 minutes. Then, the temperature is adjusted to 110°C, and magnesium hydroxide coated with attapulgite clay, zirconium phosphate coated with attapulgite clay, and silicone oil are added and rapidly mixed for 3 minutes to obtain the silicone coating layer 103. Then, the tin-plated copper wire prepared in step 2) and the silicone coating layer 103 are fed into an extrusion device together and the silicone coating layer 103 is coated on the surface of the tin-plated copper wire 102 through a co-extrusion process of related technology.

[0066] Here, the inventors need to describe attapulgite-coated magnesium hydroxide and attapulgite-coated zirconium phosphate. In a typical process, magnesium hydroxide and attapulgite are mixed in a mass ratio of 1:1 to 1:2. Diisononyl phthalate (DINP) at 10% wt of magnesium hydroxide is added as a plasticizer and closure agent to increase the dispersibility of the coating material in the silica gel coating layer 103. At the same time, it appropriately reduces the porosity between the attapulgite layered structure, or appropriately reduces the density and size of the pores, to ensure the coating of magnesium hydroxide particles. Then, the magnesium hydroxide, attapulgite, and diisononyl phthalate prepared in the specified proportions are rapidly stirred and mixed in a mixer at a relatively low temperature of 40°C-50°C, and then allowed to stand for 12 hours to obtain magnesium hydroxide material coated with attapulgite.

[0067] In another typical process, zirconium phosphate and attapulgite are mixed at a mass ratio of 1:0.5 to 1:1.5, and diisononyl phthalate (DINP) at 10% wt of zirconium phosphate is added as a plasticizer and closure agent. Then, the zirconium phosphate, attapulgite, and diisononyl phthalate are mixed in a mixer at 40℃-50℃, and then allowed to stand for 12 hours to obtain zirconium phosphate material coated with attapulgite.

[0068] Step 4) Forming the outer layer 104 structure

[0069] Although the silicone coating layer 103 can protect the wire, the material prepared by the above process will exhibit certain rheological properties under long-term high-temperature conditions, thus affecting the overall use of the wire. Therefore, a relatively robust outer jacket structure is needed. In the art, the outer jacket structure is typically made of an organic polymer material containing chlorine (Cl), because chlorine-containing polymer materials can provide the outer packaging structure of the wire with good toughness and the required strength. In the embodiments of the present invention, the outer jacket 104 is made by mixing 100 parts of polyvinyl chloride (PVC) and 10 parts by weight of diisononyl phthalate (DINP). The outer jacket 104 structure can be prepared as a film or sheet material, and then composited with the wire composite structure including the silicone coating layer 103 prepared in step 3), so that the outer jacket 104 structure only covers the outer surface of the above-mentioned wire composite structure. The specific process of coating the outer jacket 104 structure can be formed by the wire coating process of relevant existing technology, and will not be described in detail here.

[0070] From steps 1) to 4) above, the following is prepared: Figure 1 The material structure of the silicone coating on the tinned copper wire of this embodiment is shown.

[0071] Examples 2 to 4

[0072] In the following embodiments, steps 1) to 4) of the manufacturing process for coating silicone wires are similar to those in Example 1. This includes using the same types of raw materials as the silicone coating layer 103 in Example 1, and also includes components of attapulgite-coated magnesium hydroxide and attapulgite-coated zirconium phosphate. The difference is that the proportions of the components used in step 3) are adjusted. Specific implementation schemes are shown in Table 2 below:

[0073] Table 2: Raw material ratio of silicone coating layer in each embodiment (parts by weight)

[0074] Silicone coating raw materials Example 2 Example 3 Example 4 silicone rubber 30 70 90 TEO 50 30 20 Styrene-butadiene rubber 10 5 5 Polypropylene fiber 2 15 10 Magnesium hydroxide coated with attapulgite soil 3 20 15 Zirconium phosphate coated with attapulgite soil 5 10 20 silicone oil 1 5 10

[0075] In high-power wire and cable applications operating under high-temperature conditions, Mg-based materials (such as magnesium hydroxide) are preferred for their heat insulation, flame retardancy, and maintenance of a certain degree of flexibility in the protective material. However, it is often unavoidable to use encapsulations containing chloride (Cl) elements (such as the PVC components used in outer sheath materials) among other components used in the sheathing. Under the high-temperature conditions of new energy vehicles and high-power energy storage equipment, chloride elements from other components or encapsulations can penetrate into the silicone coating layer 103 to form chlorides (such as magnesium chloride). The increased activity of Cl ions after magnesium chloride formation can invade the surface protective layer of tin-plated copper wires and may even corrode the surface of the tin-plated copper wires, leading to undesirable changes in the electrical conductivity and dielectric insulation properties of the wire material. Furthermore, magnesium chloride typically has a certain degree of hygroscopic wetting properties. When hygroscopic chlorides are formed, they absorb moisture from the air to form hydrates, creating an atmosphere of water droplets and water vapor within the space between the wire insulation and conductive structures. This can degrade the communication characteristics of the tin-plated copper wires used for signal transmission. Therefore, this implementation plan addresses how to maintain the high-efficiency insulation, heat insulation, and fire-retardant properties of magnesium hydroxide while avoiding the generation of chloride ion compounds or the penetration and corrosion of chloride ions on insulating materials, conductive components, etc.

[0076] The inventors have surprisingly discovered through experiments that by using both zirconium phosphate and magnesium hydroxide as heat-insulating particles, and simultaneously performing a pre-coating process of magnesium hydroxide and zirconium phosphate separately with an appropriate proportion of attapulgite clay, the insulation, heat resistance, and high-temperature resistance properties can be enhanced. Furthermore, this process can effectively prevent the adverse effects of external chlorine intrusion on the electrical signal transmission of tin-plated copper wires. Moreover, the wire insulation coating process in this embodiment does not require the use of other fire-resistant insulating components (such as bromides) that produce toxic or environmentally harmful factors. This will be explained in detail in the comparative examples and test cases below.

[0077] Comparative Example 1

[0078] In this comparative example, a preparation process similar to steps 1) to 4) of Example 1 was used, except that in the fabrication of the silica gel coating layer 103 in step 3), attapulgite clay was not used to coat magnesium hydroxide and zirconium phosphate; instead, the corresponding components were directly mixed in a mixer. In Comparative Example 1, step 3) was performed according to the following steps (in parts by weight):

[0079] Prepare 50 parts of silicone rubber, 50 parts of TEO polyolefin thermoplastic elastomer, 5 parts of styrene-butadiene rubber, 5 parts of polypropylene fiber, 5 parts of magnesium hydroxide, 5 parts of zirconium phosphate, 10 parts of attapulgite clay, and 2 parts of silicone oil.

[0080] In the preparation process, the prepared silicone rubber, TEO polyolefin thermoplastic elastomer, styrene-butadiene rubber, and polypropylene fiber are first put into a mixer and heated to 160°C for 10 minutes. Then, the temperature is adjusted to 110°C, and magnesium hydroxide, zirconium phosphate, attapulgite clay, and silicone oil are added and rapidly mixed for 3 minutes to obtain the silicone coating material. Subsequently, the prepared tin-plated copper wire and the silicone coating material are fed into an extrusion device to coat the surface of the tin-plated copper wire with the silicone coating.

[0081] Comparative Example 2

[0082] In this comparative example, a preparation process similar to steps 1) to 4) of Example 1 was used, except that magnesium hydroxide was not used or magnesium hydroxide coated with attapulgite clay was not used in the fabrication of the silicone coating layer 103 in step 3). In Comparative Example 2, step 3) was performed according to the following steps (in parts by weight):

[0083] Prepare 50 parts of silicone rubber, 50 parts of polyolefin thermoplastic elastomer, 5 parts of styrene-butadiene rubber, 5 parts of polypropylene fiber, 8 parts of zirconium phosphate coated with attapulgite clay, and 2 parts of silicone oil.

[0084] In the preparation process, the prepared silicone rubber, TEO polyolefin thermoplastic elastomer, styrene-butadiene rubber, and polypropylene fiber are first put into a mixer and heated to 160°C for 10 minutes. Then, the temperature is adjusted to 110°C, and zirconium phosphate coated with attapulgite clay and silicone oil are added and rapidly mixed for 3 minutes to obtain the silicone coating material. Subsequently, the prepared tin-plated copper wire and the silicone coating material are fed into an extrusion device to coat the surface of the tin-plated copper wire with the silicone coating.

[0085] Comparative Example 3

[0086] In this comparative example, a preparation process similar to steps 1) to 4) of Example 1 was used, except that in the fabrication of the silicone coating layer 103 in step 3), zirconium phosphate material or zirconium phosphate material coated with attapulgite clay was not used; only magnesium hydroxide was used. In Comparative Example 3, step 3) was performed according to the following steps (in parts by weight):

[0087] Prepare 50 parts of silicone rubber, 50 parts of TEO polyolefin thermoplastic elastomer, 5 parts of styrene-butadiene rubber, 5 parts of polypropylene fiber, 8 parts of magnesium hydroxide coated with attapulgite clay, and 2 parts of silicone oil.

[0088] In the preparation process, the prepared silicone rubber, TEO polyolefin thermoplastic elastomer, styrene-butadiene rubber, and polypropylene fiber are first put into a mixer and heated to 160°C for 10 minutes. Then, the temperature is adjusted to 110°C, and magnesium hydroxide coated with attapulgite and silicone oil are added and rapidly mixed for 3 minutes to obtain the silicone coating layer 103 material. Then, the prepared tin-plated copper wire and the silicone coating layer material are fed into the extrusion equipment to coat the surface of the tin-plated copper wire with the silicone coating layer.

[0089] Comparative Example 4

[0090] In this comparative example, a preparation process similar to steps 1) to 4) of Example 1 was used, except that uncoated magnesium hydroxide and zirconium phosphate materials were used in the fabrication of the silicone coating layer 103 in step 3). In Comparative Example 4, step 3) was performed according to the following steps (in parts by weight):

[0091] Prepare 50 parts of silicone rubber, 50 parts of TEO polyolefin thermoplastic elastomer, 5 parts of styrene-butadiene rubber, 5 parts of polypropylene fiber, 5 parts of magnesium hydroxide, 5 parts of zirconium phosphate, and 2 parts of silicone oil.

[0092] In the preparation process, the prepared silicone rubber, TEO polyolefin thermoplastic elastomer, styrene-butadiene rubber, and polypropylene fiber are first put into a mixer and heated to 160°C for 10 minutes. Then, the temperature is adjusted to 110°C, and magnesium hydroxide, zirconium phosphate, and silicone oil are added and rapidly mixed for 3 minutes to obtain the silicone coating material. Then, the tin-plated copper wire prepared in step 2) and the silicone coating material are put into the extrusion equipment together to coat the surface of the tin-plated copper wire with the silicone coating.

[0093] Test Experiment 1

[0094] Before describing the various test experiments, the embodiments and comparative experiments of this invention used the same sample preparation for each test. Specifically, five tinned copper wires (insulated with simple polyester tape) with a diameter of 0.25 mm were twisted and wrapped around a copper core conductor with a diameter of 1.50 mm (e.g., Figure 1 On 101), a coating material containing the above-mentioned components is extruded onto the periphery of the obtained tin-plated copper wire composite to form a silicone coating layer with a thickness of 0.90 mm (e.g., silicone coating layer 103). Next, a PVC-based outer coating layer (e.g., 104) with a thickness of approximately 0.90 mm to 1.05 mm is formed.

[0095] The composite structure of the signal wire (tinned copper wire) and parallel power line (copper core conductor) formed above will be kept at a predetermined temperature of 150°C to 160°C for a predetermined time (e.g., 30 days or 720 hours under simulated operating conditions).

[0096] Regarding the structure in which the above-mentioned assembly is held at a predetermined temperature for a predetermined time, after cooling at room temperature, the characteristic impedance in differential mode is measured for a communication wire. The characteristic impedance can be measured using the open / short circuit method with an LCR meter, as described in related technologies, to test the resistance change of the composite wire material.

[0097] For chlorides (such as magnesium chloride or chloride ions) generated after heating, the products in the sleeve of the heated silicone coating layer 103 are analyzed. The analysis involves freezing the surface material adhering to the silicone coating layer and the tin-plated copper wire, pulverizing the frozen material to obtain a powder, and then using gas chromatography to determine the generated chlorides.

[0098] Test Experiment 2

[0099] The AC voltage breakdown test is conducted according to GB / T3048.8-2007 "Test Methods for Electrical Properties of Wires and Cables" Part 8: AC Voltage Test, with a power frequency voltage of 4U0. The test is to see how many hours the corresponding wire material does not break down (usually the test pass time should be greater than 4 hours).

[0100] Test Experiment 3

[0101] Fire resistance can be tested according to the test method of BS8491:2008 "Assessment of fire integrity of large-diameter power cables for smoke and heat control systems and other specific ongoing fire safety system components", and observe how long (minutes) the fuse does not break and the indicator light does not go out.

[0102] Test Experiment 4

[0103] Tensile tests were performed on the generated silicone coating material to determine its elastic modulus. Tensile tests were conducted according to JIS K 7161-1:2014 to determine the range of elastic modulus values ​​(in MPa) of the silicone coating material in each embodiment or comparative example.

[0104] The test results for each experimental example and comparative example can be found in Table 3 below:

[0105] Table 3: Performance test results of the examples and comparative examples

[0106] (E represents the corresponding embodiment, and C represents the corresponding comparative example)

[0107] Experiment / Test Magnesium chloride production (g / Mg) Characteristic impedance (ohms) Alternating current breakdown (hours) Elastic modulus (MPa) Fire resistance (minutes) E1 0.8 102 >10 75 >180 E2 1.2 105 >10 78 >180 E3 1.1 110 >10 72 >180 E4 1.3 109 >10 80 >180 C1 4.0 50 >10 90 C2 -- 95 >10 55 <120 C3 2.2 78 <6 65 >180 C4 9 10 <4 58 <140

[0108] Regarding the above test results, the inventors do not wish to be bound by any chemical or physical theoretical explanations. However, based on experimental observations, the inventors believe that the core-shell structure formed by separately coating magnesium hydroxide and zirconium phosphate with attapulgite in the embodiments can not only effectively maintain the good and stable electrical properties (conductivity and dielectric properties) of tin-plated copper wire, but also maintain good high-temperature resistance, making the wire structure suitable for high-power output current and outputting corresponding control signals under high-temperature conditions. In the embodiments, by separately coating magnesium and zirconium materials with attapulgite, the chain-like layered structure of attapulgite (forming chain-like layered silicates) effectively encapsulates magnesium hydroxide. At the same time, by controlling the gaps between the chain-like layered structures through static treatment and toughening closed-cell materials, it is difficult for the Cl element in the outer shell to form MgCl2 with Mg at high temperatures. Even if trace amounts of MgCl2 are formed, they are contained by the layered and semi-closed structure of attapulgite under the condition of being coated on the outer layer, and will not extend towards the tin-plated copper wire or copper core, thus maintaining the resistive characteristics of the wire structure well without large fluctuations. In contrast, the inventors surprisingly discovered that if attapulgite is directly mixed with Mg and Zr-based refractory materials at high temperatures to form the final material (Comparative Example 1), although the diffusion of Cl element is reduced to some extent compared to a material system without attapulgite, the effect is far less than that of pre-coated magnesium hydroxide and zirconium phosphate coated with attapulgite. One possible explanation is that during the high-temperature mixing stage, magnesium hydroxide does not have enough time to be incorporated into the layered space of attapulgite. Furthermore, without the help of plasticizers and closed-cell components, the dispersion of magnesium hydroxide and zirconium phosphate molecules is insufficient, potentially causing particle aggregation and making it impossible to avoid contact with Cl element intrusion at high temperatures. Simultaneously, the layered space of attapulgite itself may have excessively large pores, which, when in a certain rheological state at high temperatures, may not be able to effectively protect the magnesium hydroxide component.

[0109] In the coating conditions and process of this invention, the preferred mass ratio of magnesium hydroxide to attapulgite used for coating is 1:1 to 1:2, and the preferred mass ratio of zirconium phosphate to attapulgite used for coating is 1:0.5 to 1:1.5. In comparison, magnesium hydroxide requires a relatively thicker coating, while zirconium phosphate can be coated more thinly. However, it should be noted that the mass ratio of magnesium hydroxide and / or zirconium phosphate to attapulgite used for coating should not exceed 1:3 or higher. When the attapulgite content is too high, it is impossible to achieve more effective coating of magnesium hydroxide. Furthermore, under high temperature environments and operating conditions, it may increase the rheological properties of the coating layer, leading to deterioration of mechanical properties, or cause porosity in the coating layer, allowing chloride (Cl) elements to invade from the outside.

[0110] In addition, it is worth noting that the coated zirconium phosphate also plays an auxiliary role in preventing the combination of Mg and Cl (as in Comparative Example 3). When both coated zirconium phosphate and coated magnesium hydroxide are present, the zirconium phosphate itself has more stable chemical and physical properties. After coating, the zirconium phosphate forms more favorable attapulgite fixation sites, which helps to fix and absorb the invading Cl from the outside, and further prevents Cl from forming with Mg in a way that would be detrimental to the absorption of water and permeable substances.

[0111] The inventors discovered that the combination of magnesium oxide and zirconium phosphate ensures both impedance characteristics and fire resistance and insulation properties. When magnesium hydroxide is not used at all (as in Comparative Example 2), the fire resistance and heat resistance are relatively deteriorated; while when only magnesium hydroxide is used (Comparative Example 3), the insulation properties are slightly insufficient. Therefore, the coated zirconium phosphate helps to prevent the intrusion of Cl element from the outside, while forming stable and good core-shell sites, providing good insulation and fire resistance properties.

[0112] Application Example 1

[0113] The tin-plated copper wire composite structure prepared by the silicone coating process in this embodiment can be used in new energy vehicles, energy storage structures, or high-power electrical appliances. The wires can be freely combined, installed, or redirected. A typical application scenario can be found by referring to... Figure 2 . Figure 2 In this paper, a composite wire structure 100, which uses a silicone coating process to coat composite tin-plated copper wires, is applied to the field of snap-fit ​​wiring in certain parts of a vehicle body. For example... Figure 2 The composite wire structure 100 shown has a first snap-fit ​​structure 201 at one end and a second snap-fit ​​structure 202 at the other end. The surface of the second snap-fit ​​structure 202 is recessed to form a socket (not shown). The first snap-fit ​​structure 201 is adapted to the socket, that is, the first snap-fit ​​structure 201 can be inserted into the socket and can also be pulled out of the socket. The copper core conductor 101 inside the composite wire structure 100 (see...) Figure 1 The first snap-fit ​​structure 201 and the second snap-fit ​​structure 202 are electrically connected; when the first snap-fit ​​structure 201 of a composite wire structure 100 is inserted into the socket of the composite wire structure 100, the signals or circuits inside the two composite wire structures 100 are connected. On the other hand, if it is necessary to separate the power supply and signal transmission, the copper core conductor 101 and the tinned copper wire 102 can be led out and connected to the outside, while maintaining insulation between them.

[0114] The surface of the first snap-fit ​​structure 201 is provided with multiple snap-fit ​​blocks 203, which are evenly spaced around the surface of the first snap-fit ​​structure 201 and located near the composite wire structure 100. The surface of the second snap-fit ​​structure 202 is provided with multiple rotating block interfaces 204, which are evenly spaced around the surface of the second snap-fit ​​structure 202. An adapter plate 205 is rotatably mounted on the rotating block interface 204. The adapter plate 205 is elongated and aligned with the snap-fit ​​blocks 203, meaning that the adapter plate 205 can rotate within the rotating block interface 204, and its front end can approach the snap-fit ​​blocks 203. The side of the card block 203 away from the rotating block interface 204 is provided with a card slot 206. The lower surface of the adapter plate 205 away from the rotating block interface 204 is provided with a hook 207. The front end of the hook 207 engages with the card slot 206, that is, the front end of the hook 207 can enter into the card slot 206 and can also leave the card slot 206.

[0115] The end of the first snap-fit ​​structure 201 furthest from the composite wire structure 100 can be fitted with a sealing ring (not shown). The cross-sectional size of the sealing ring can gradually increase, allowing the first snap-fit ​​structure 201 to be securely inserted into the socket and preventing it from easily falling off. This allows for free connection, reversal, or fixing of different cables. Furthermore, in this application scenario, if along... Figure 2 A cross-sectional view of "AA" as shown can yield a result similar to... Figure 1 The tin-plated copper wire composite structure shown in this embodiment of the invention is prepared by a process using coated silicone.

[0116] It is worth noting that the embodiments of the present invention do not wish to use a coating layer structure with an excessively high elastic modulus. If the elastic modulus of the silicone coating layer 103 is too high (e.g., exceeding 100 MPa), it may cause excessive line tension or difficulty in shaping and routing the lines during complex wiring. In a typical embodiment, it is desirable for the silicone coating layer 103 to have an appropriate elastic modulus, preferably between 60 and 80 MPa, as described in the embodiments.

[0117] Application Example 2

[0118] The tin-plated copper wire composite structure prepared by the silicone coating process in the embodiments of the present invention can also be implemented as a single-strand cable or a multi-strand cable in parallel, such as... Figure 3 As shown in the photograph. Similar processes can expand the application areas of the tin-plated copper wire composite structure prepared by the silicone-coated process of this invention.

[0119] Based on the embodiments and technical content described in this specification, the present invention can provide at least the following technical solutions: Although this disclosure includes specific embodiments, it will be apparent to those skilled in the art that various substitutions or changes in form and detail can be made to these embodiments without departing from the inventive spirit and scope of the claims and their equivalents. The embodiments described herein should be considered illustrative only and not for limiting purposes. The description of features and aspects in each embodiment is considered applicable to similar features and aspects in other embodiments. Therefore, the scope of this disclosure should not be limited by the specific description, but rather by the technical solutions of the claims, and all variations within the scope of the claims and their equivalents are to be interpreted as included within the technical solutions of this disclosure.

Claims

1. A method for preparing silicone coating for tin-plated copper wires, characterized in that, The method includes the following steps: The step of providing a conductor includes providing a conductor comprising tin-plated copper wires; The step of fabricating a silicone coating layer includes coating the surface of the conductive body containing tin-plated copper wires with a silicone coating layer, the silicone coating layer comprising magnesium hydroxide coated with attapulgite and zirconium phosphate coated with attapulgite; and The step of forming an outer layer includes forming an outer layer on the outer surface of the silicone coating layer, the outer layer containing chlorine, preferably, the outer layer containing a chlorine-containing polymer.

2. The method for preparing coated silicone for tin-plated copper wires according to claim 1, wherein the step of providing the conductor includes: Step 1), prepare the copper core conductor; as well as Step 2) Using the copper core conductor as the core, wrap the tin-plated copper wire around it; preferably, the tin-plated copper wire is covered with an insulating material before wrapping the copper core conductor.

3. The method for preparing the silicone coating for tin-plated copper wires according to claim 1, wherein the step of preparing the silicone coating layer includes: Step 3) Prepare raw material components including silicone rubber, polyolefin thermoplastic elastomer, styrene-butadiene rubber, polypropylene fiber, magnesium hydroxide coated with attapulgite clay, zirconium phosphate coated with attapulgite clay, and silicone oil. First, the prepared silicone rubber, polyolefin thermoplastic elastomer, styrene-butadiene rubber, and polypropylene fiber are put into a mixer for mixing; then magnesium hydroxide coated with attapulgite clay, zirconium phosphate coated with attapulgite clay, and silicone oil are added, and a second mixing is carried out to obtain the silicone coating material. as well as The silicone coating layer is applied to the surface of the tin-plated copper wire.

4. The method for preparing the silicone coating for tin-plated copper wires according to any one of claims 1 to 3, wherein the attapulgite-coated magnesium hydroxide and the attapulgite-coated zirconium phosphate are prepared by the following method: Magnesium hydroxide and attapulgite are mixed in a mass ratio of 1:1 to 1:2, and a plasticizing and sealing agent of 5%wt-10%wt of magnesium hydroxide mass is added. The magnesium hydroxide, attapulgite, and plasticizing and sealing agent are mixed in a mixer and then allowed to stand for 10-20 hours to obtain magnesium hydroxide material coated with attapulgite. Zirconium phosphate and attapulgite are mixed at a mass ratio of 1:0.5 to 1:1.5, and a plasticizer / sealing agent accounting for 5% wt-10% wt of the zirconium phosphate mass is added. Then, the zirconium phosphate, attapulgite, and plasticizer / sealing agent are mixed in a mixer, and then allowed to stand for 10-20 hours to obtain a zirconium phosphate material coated with attapulgite; and preferably, [the following is a more specific description of the process]. The plasticizer / clotting agent is diisononyl phthalate (DINP).

5. A method for preparing coated silicone for tin-plated copper wires according to any one of claims 1 to 4, wherein the method specifically comprises the following steps: Step 1) Prepare a copper core conductor; Step 2) Using a copper core conductor as the core, wrap around the tin-plated copper wire; wherein the tin-plated copper wire is wrapped with insulating polyester tape on its surface before being wrapped. Step 3) Prepare the silicone coating layer: by weight, prepare 20-100 parts of silicone rubber, 20-60 parts of polyolefin thermoplastic elastomer, 2-10 parts of styrene-butadiene rubber, 1-15 parts of polypropylene fiber, 5-20 parts of magnesium hydroxide coated with attapulgite clay, 5-20 parts of zirconium phosphate coated with attapulgite clay, and 1-5 parts of silicone oil as raw material components. First, silicone rubber, polyolefin thermoplastic elastomer, styrene-butadiene rubber, and polypropylene fiber are placed in a mixer and heated to 120-160℃ for 5-15 minutes. Then, the temperature is adjusted to 90℃-110℃, and magnesium hydroxide coated with attapulgite clay, zirconium phosphate coated with attapulgite clay, and silicone oil are added and mixed for 1-5 minutes to obtain the silicone coating material. Subsequently, the tin-plated copper wire prepared in step 2) and the silicone coating material are fed into an extrusion device, and the silicone coating is coated onto the surface of the tin-plated copper wire using a co-extrusion process. Step 4) Forming the outer layer structure: A film or sheet material containing 80-120 parts by weight of polyvinyl chloride (PVC) and 5-15 parts by weight of diisononyl phthalate (DINP) is used to make the outer layer, and then it is wrapped around the outer surface of the tin-plated copper wire containing the silicone coating layer obtained in step 3) above.

6. The method for preparing the silicone coating for tin-plated copper wires according to any one of claims 1 to 5, wherein the elastic modulus of the silicone coating layer is between 60 MPa and 80 MPa.

7. A composite structure of silicone-coated tin-plated copper wire prepared by the method of any one of claims 1 to 6, wherein the composite structure comprises: Copper core conductor; Tin-plated copper wire covering the outside of the copper core conductor; A silicone coating layer covering the outside of the tin-plated copper wire; as well as A chlorine-containing outer layer covering the outside of the silicone coating layer.

8. The composite structure of tin-plated copper wire coated with silicone according to claim 7, wherein the silicone coating layer has an elastic modulus between 60 MPa and 80 MPa.

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