Lightweight flexible wear-resistant electrical equipment connecting cable

Abstract

The application relates to the technical field of cable material manufacturing, and discloses a light-weight flexible wear-resistant electrical equipment connecting cable, a sheath of the connecting cable being made of raw materials including the following: polyester type thermoplastic polyurethane elastomer, styrene-acrylonitrile copolymer, maleic anhydride grafted polyolefin elastomer, blocked isophorone diisocyanate, wear-resistant premixed solution containing a catalyst, slow-release foaming master batch and functional additives; wherein the wear-resistant premixed solution containing the catalyst contains hydroxyl-terminated polydimethylsiloxane and a bismuth octoate catalyst, the slow-release foaming master batch contains modified azodicarbonamide foaming agent and carrier resin, and the functional additives contain antioxidants and carbodiimide hydrolysis stabilizers. According to the application, the hydroxyl-terminated polydimethylsiloxane containing the catalyst and the blocked isocyanate are introduced into the polyurethane matrix in cooperation through a reaction extrusion process, the isocyanate groups are unblocked at high temperature, and the organic silicon chain segment is chemically bonded with the matrix resin.

Description

Technical Field

[0001] This invention relates to the field of cable material manufacturing technology, specifically to a lightweight, flexible, and wear-resistant electrical equipment connection cable. Background Technology

[0002] In the field of modern industrial automation and mobile electrical equipment, connecting cables, as the lifeblood of power and signal transmission, need to frequently reciprocate along with equipment booms or cable chain systems. To reduce the load energy consumption of drive motors and facilitate manual on-site installation, lightweight cable design has become an industry trend. Simultaneously, because cables are constantly in contact with and rubbed against rough surfaces such as concrete floors and metal rails, the sheath material must possess extremely high wear resistance and flexibility to prevent damage or cracking during long-term dragging, thereby ensuring the safe operation of the electrical system.

[0003] Polyester-based thermoplastic polyurethane elastomers are the preferred substrate for high-end cable sheaths due to their excellent mechanical strength, oil resistance, and abrasion resistance. To reduce material density, existing processing techniques typically employ chemical foaming, which involves adding chemical foaming agents such as azodicarbonamide to the resin. The gases released from the decomposition of these agents at high temperatures form a cellular structure within the matrix. Furthermore, to reduce the coefficient of friction on the cable surface, simple physical blending modification is commonly used industrially. This involves directly mixing and extruding dimethyl silicone oil or amide-based lubricants with TPU particles. This method is simple to operate and can effectively improve the smoothness of the cable surface in the initial stages.

[0004] However, this traditional blending foaming process has revealed significant drawbacks in practical applications. Azo-based foaming agents release alkaline byproducts such as ammonia during decomposition, and polyester-based polyurethane is extremely sensitive to acids and alkalis. Residual alkaline substances induce hydrolysis and chain scission of ester bonds, leading to a sharp decrease in the molecular weight of the matrix resin, making the sheath material brittle and losing its tear resistance. Regarding lubrication modification, physically added silicone oil has poor compatibility with the polar TPU matrix and lacks chemical bonding, making it prone to migrating to the surface after long-term use. This not only causes lubrication failure but also makes the cable surface sticky and attracts dust. Furthermore, conventional extrusion processes struggle to balance the temperature requirements of chemical reactions and physical foaming. The foaming agent often decomposes prematurely due to excessive heating time, leading to melt fracture and preventing the achievement of a dense and smooth sheath surface. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a lightweight, flexible, and wear-resistant electrical equipment connection cable. This solves the technical problem that existing polyester thermoplastic polyurethane cables, during the chemical foaming weight reduction process, suffer from matrix degradation induced by foaming byproducts and the migration and precipitation of physical lubricants, resulting in an inability to simultaneously achieve lightweight, high strength and toughness, and long-term wear resistance.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a lightweight, flexible, and wear-resistant electrical equipment connection cable, employing the following technical solution: A lightweight, flexible, and wear-resistant electrical equipment connecting cable, wherein the sheath of the connecting cable is made by reactive extrusion of the following raw materials in parts by weight: 100 parts of polyester thermoplastic polyurethane elastomer; 3-8 parts of styrene-acrylonitrile copolymer; 0.5-2.5 parts of maleic anhydride-grafted polyolefin elastomer; 1.0-3.0 parts of end-capped isophorone diisocyanate; 2.0-6.0 parts of a wear-resistant premix containing a catalyst; 1.5-3.0 parts of slow-release foaming masterbatch; and 0.8-1.5 parts of functional additives; wherein the wear-resistant premix containing a catalyst contains hydroxyl-terminated polydimethylsiloxane and bismuth isooctanoate catalysts, the slow-release foaming masterbatch contains modified azodicarbonamide foaming agent and carrier resin, and the functional additives contain antioxidants and carbodiimide hydrolysis stabilizers.

[0007] By adopting the above technical solution, the in-situ chemical modification and microporous foaming of each component were simultaneously controlled using reactive extrusion technology. The mechanism of action is as follows: First, durable wear resistance is achieved through chemical grafting. End-capped isophorone diisocyanate undergoes decapsulation during the high-temperature extrusion stage, releasing highly active isocyanate groups. Under the action of a bismuth isooctanoate catalyst, these isocyanate groups react with active hydrogen on the molecular chain of the polyester thermoplastic polyurethane elastomer and with terminal hydroxyl polydimethylsiloxane in the catalyst-containing wear-resistant premix. This reaction chemically grafts organosilicon segments onto the polyurethane matrix backbone, solving the problem of easy precipitation of traditional small-molecule silicone oils. This results in a stable, low-friction layer on the sheath surface, achieving long-lasting wear resistance.

[0008] Second, microporous foaming and matrix protection work synergistically. During extrusion, the slow-release foaming masterbatch decomposes upon heating, generating gas and forming a microporous structure to reduce cable density. Addressing the degradation risk to polyester-based thermoplastic polyurethane elastomers posed by alkaline byproducts such as ammonia produced from the decomposition of azodicarbonamide foaming agent, maleic anhydride-grafted polyolefin elastomers act as acid scavengers. Their maleic anhydride groups preferentially react with alkaline substances like ammonia to form imide structures, thereby inhibiting the degradation of polyurethane molecular weight by the ammonolysis reaction and maintaining the mechanical properties of the matrix material.

[0009] Third, compatibility enhancement and melt reinforcement. The rigid segments of the styrene-acrylonitrile copolymer dispersed in the polyurethane matrix improve melt strength, helping to maintain the stability of the bubble structure and prevent bubble breakage or collapse. Simultaneously, the graft copolymers generated in situ during the reaction of the maleic anhydride-grafted polyolefin elastomer are distributed at the interface between the polyurethane and polyolefin, enhancing the interfacial bonding force. This allows the sheath material to maintain high tensile strength and tear resistance while achieving weight reduction through foaming.

[0010] Preferably, the raw materials are in the following weight proportions: 100 parts of polyester thermoplastic polyurethane elastomer; 5 parts of styrene-acrylonitrile copolymer; 1.5 parts of maleic anhydride grafted polyolefin elastomer; 2.0 parts of end-capped isophorone diisocyanate; 4.0 parts of abrasion-resistant premix containing catalyst; 2.0 parts of slow-release foaming masterbatch; and 0.8 parts of functional additives.

[0011] By adopting the above technical solution, this formulation balances the foaming ratio and weight reduction effect, while also taking into account mechanical properties and wear resistance. The specific ratio of styrene-acrylonitrile copolymer to grafted elastomer endows the melt with suitable viscoelasticity, enabling the formation of a uniform and fine cell structure; the amount of wear-resistant premix containing catalyst is sufficient to form a continuous low-friction effect on the material surface.

[0012] Preferably, in the catalyst-containing wear-resistant premix, the amount of bismuth isooctanoate catalyst added is 0.1-0.2 parts by weight relative to 100 parts by weight of hydroxyl-terminated polydimethylsiloxane; the kinematic viscosity of the hydroxyl-terminated polydimethylsiloxane at 25°C is 5000-10000 cSt; in the slow-release foaming masterbatch, the weight ratio of modified azodicarbonamide foaming agent to carrier resin is 30-40:60-70; the carrier resin is ethylene-vinyl acetate copolymer or low-melting-point thermoplastic polyurethane.

[0013] By employing the above technical solutions and limiting the content of bismuth isooctanoate catalyst, the rate of the organosilicon grafting reaction can be controlled to match the residence time in the extruder, ensuring both the grafting rate and avoiding local cross-linking caused by excessively rapid reaction. The selection of high-viscosity hydroxyl-terminated polydimethylsiloxane reduces its diffusion rate in the melt, making it easier to be fixed in the matrix network through the isocyanate reaction. Controlling the ratio of blowing agent to carrier and the type of carrier ensures the uniform dispersion of the blowing agent in the polyurethane matrix, preventing large cell defects caused by excessively high local gas concentrations.

[0014] Preferably, the maleic anhydride-grafted polyolefin elastomer uses ethylene-octene copolymer as the matrix, and the maleic anhydride grafting rate is 0.8%-1.2%; the end-capped isophorone diisocyanate is caprolactam-capped, and the uncapping temperature is 150℃-160℃.

[0015] By adopting the above technical solution, the ethylene-octene copolymer matrix provides good flexibility, and the grafting rate of 0.8%-1.2% provides sufficient reaction sites to capture alkaline gases and perform interfacial compatibilization. The use of caprolactam-terminated isophorone diisocyanate and the control of the desealing temperature at 150℃-160℃ ensures its chemical inertness in the melt dispersion section of the extruder until it enters the high-temperature reaction section, thus achieving a match between the chemical reaction and physical mixing process windows.

[0016] Secondly, the present invention provides a method for preparing lightweight, flexible, and wear-resistant electrical equipment connection cables, employing the following technical solution: A method for preparing a lightweight, flexible, and wear-resistant electrical equipment connection cable includes the following steps: S1. The polyester thermoplastic polyurethane elastomer, styrene-acrylonitrile copolymer, maleic anhydride grafted polyolefin elastomer, end-capped isophorone diisocyanate and functional additives are mixed evenly and added as solid components from the main feed port of the twin-screw extruder. S2. The abrasion-resistant premix containing the catalyst is injected into a twin-screw extruder as a liquid component, and the injection position is located after the solid component has melted. S3. The slow-release foaming masterbatch is added as a side feed component from the side feed port of the twin-screw extruder, which is located downstream of the liquid component injection position. S4. Control the temperature distribution of the twin-screw extruder so that the material successively undergoes the processes of melting and dispersion, catalytic grafting, side feeding and mixing, and foaming reaction before being extruded through the die head; S5. The extruded melt is coated onto the surface of the conductor and then cooled and shaped by a multi-stage water bath gradient.

[0017] By adopting the above technical solution, and utilizing a segmented feeding strategy and temperature zone control technology, the contradiction between the different temperature and residence time requirements of reaction grafting and physical foaming in the same extrusion process is resolved, as detailed below: First, a stable melt delivery state was established through the main feeding and melting of the solid components. The catalyst-containing wear-resistant premix was injected after the solid components were melted, avoiding screw slippage caused by the liquid components and ensuring extrusion stability. Simultaneously, it ensured that the hydroxyl-terminated polydimethylsiloxane was uniformly dispersed in the polyurethane matrix before the isocyanate capping was removed. When the material was conveyed to the intermediate reaction zone, the catalyst induced an in-situ grafting reaction of the unsealed isocyanate groups, forming a stable chemically bonded wear-resistant layer.

[0018] Secondly, the use of side-feeding technology to add slow-release foaming masterbatch downstream significantly shortens the residence time of the heat-sensitive foaming agent in the high-temperature barrel. This delayed feeding method spatially separates the mixing process of the foaming agent from the upstream grafting reaction process, preventing premature decomposition of the foaming agent that could lead to melt fracture, and ensuring that the foaming behavior mainly occurs in the die head extrusion stage, thereby obtaining a dense microporous sheath structure.

[0019] Preferably, in step S2, the liquid component is injected into the third barrel of the twin-screw extruder; in step S3, the side-feed component is added from the seventh barrel of the twin-screw extruder; the length-to-diameter ratio of the twin-screw extruder is ≥48:1; in step S4, the screw speed of the twin-screw extruder is set to 280-350 rpm.

[0020] By adopting the above technical solution, the high aspect ratio equipment provides ample reaction time and space for multiple chemical reactions. The third cylinder injection ensures that the solid material has been plasticized, suitable for shear dispersion of the liquid; the seventh cylinder adds foaming masterbatch, minimizing its thermal history. The high rotation speed setting of 280-350 rpm provides a strong shear environment, which promotes the micro-dispersion of silicone and polyurethane, improves the efficiency of the grafting reaction, and the heat generated by the strong shear helps the final decomposition of the foaming agent at the die head.

[0021] Preferably, in step S4, the temperature settings of the twin-screw extruder are as follows: Zones 1-3: 140℃-160℃; Zones 4-6: 165℃-178℃; Zones 7-8: 170℃-185℃; Zones 9-11: 192℃-205℃; and the die head temperature: 180℃-190℃.

[0022] By adopting the above technical solution, a specific temperature gradient is set to adapt to the needs of chemical reactions at different stages: The low-temperature range of 140℃-160℃ is used for the melt plasticization of solid resin to prevent premature desealing of the end-capped isocyanate; The intermediate temperature range of 165℃-178℃ is the reaction initiation zone. At this temperature, the end-capping agent is decapsulated, and the grafting reaction is initiated under the action of the catalyst. The mixing zone of 170℃-185℃ is used for the dispersion of foaming masterbatch. This temperature range is below the violent decomposition temperature of the foaming agent, preventing pre-foaming from occurring in the barrel. The high-temperature zone (192℃-205℃) and the die head zone are the foaming zones. High temperature is used to induce the foaming agent to decompose rapidly and generate gas, which, together with the release of die head pressure, achieves micropore shaping.

[0023] Preferably, before step S2, the catalyst-containing wear-resistant premix is ​​prepared by the following method: bismuth isooctanoate is added to vacuum-dried hydroxyl-terminated polydimethylsiloxane under an environment with a relative humidity below 50%, stirred until homogeneous and transparent, and then subjected to vacuum degassing. Before step S3, the slow-release foaming masterbatch is prepared by the following method: the carrier resin is plasticized in a mixer, modified azodicarbonamide is added, and the mixture is kneaded at 105℃-120℃ until uniformly dispersed, followed by extrusion granulation at 100℃-115℃; the temperature of the preparation process is lower than the decomposition temperature of the modified azodicarbonamide.

[0024] By adopting the above technical solutions, the humidity control of the premix preparation environment eliminates the risk of competitive reaction between moisture and isocyanate, ensuring that isocyanate is mainly used for grafting organosilicon and matrix chain extension. The low-temperature preparation process of the foaming masterbatch ensures that azodicarbonamide does not decompose during the masterbatch processing stage, retaining its foaming properties for the final cable extrusion process, and improving the controllability of foaming efficiency.

[0025] This invention provides a lightweight, flexible, and wear-resistant electrical equipment connection cable. It has the following advantages: 1. This invention introduces catalyst-containing hydroxyl-terminated polydimethylsiloxane and end-capped isocyanate into a polyurethane matrix through reactive extrusion. The isocyanate groups are decapsulated at high temperature, inducing the organosilicon segments to chemically bond with the matrix resin. The in-situ grafting technology overcomes the defect of easy migration and precipitation of silicone oil in traditional physical blending processes. As a result, the cable sheath surface obtains durable and stable low friction characteristics, which significantly improves the wear resistance life of the material under complex working conditions.

[0026] 2. This invention uses styrene-acrylonitrile copolymer to enhance melt strength and maleic anhydride-grafted elastomer as an acid trap. On the one hand, it uses a rigid phase to support a stable microporous structure, and on the other hand, it uses anhydride groups to actively trap alkaline substances produced by the decomposition of azodicarbonamide, effectively blocking the degradation attack of alkaline byproducts on the polyurethane molecular chain. Compared with conventional TPU foaming technology, this solution can significantly reduce density while maintaining the material's excellent tensile strength and tear resistance, solving the problem of the difficulty of coexisting lightweight and high strength.

[0027] 3. This invention utilizes the segmented temperature control and multi-port feeding strategy of a twin-screw extruder to spatially separate the grafting process of liquid reactive components from the mixing process of heat-sensitive foaming masterbatch. The liquid component is injected midstream to initiate grafting, while the foaming masterbatch is fed downstream to reduce thermal history. This avoids the reaction competition and premature decomposition of the foaming agent caused by traditional mixing and feeding. The resulting cable sheath has fine and uniform foam cells and a dense and smooth outer skin, solving the process bottleneck of narrow processing window and poor surface quality of reactive foaming materials. Attached Figure Description

[0028] Figure 1 The following is a comparison chart of the physical and mechanical properties of the test examples of the present invention; wherein (a) shows a bar chart of the density distribution of each group of materials, and (b) is a scatter plot of tensile strength and density. Figure 2 The following are comparative graphs for verifying the kinetic catalytic bias mechanism of the test examples of the present invention; wherein (a) is a bar chart of wear volume; and (b) is a bar chart of mass loss rate. Figure 3 This is a scatter plot showing the correlation between residual ammonia odor level and right-angle tear strength in the test examples of this invention. Figure 4 This is a time-domain response diagram of the die head melt pressure fluctuation during the extrusion process of the test example of the present invention. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0031] Polyester-type thermoplastic polyurethane elastomer: hardness Shore 90A, melt flow rate 5-10g / 10min (190℃, 2.16kg), is a commercially available industrial-grade product.

[0032] Styrene-acrylonitrile copolymer: CAS No. 9003-54-7, acrylonitrile monomer unit mass fraction 28%-32%.

[0033] Maleic anhydride-grafted polyolefin elastomer: based on ethylene-octene copolymer, with a maleic anhydride grafting rate of 0.8%-1.2%.

[0034] End-capped isophorone diisocyanate: caprolactam-capped, uncapping temperature 150℃-160℃, effective isocyanate group content ≥13%, appearance is white micro powder.

[0035] Hydroxyl-terminated polydimethylsiloxane: CAS No. 70131-67-8, kinematic viscosity at 25℃ 5000-10000 cSt, hydroxyl mass fraction 0.05%-0.2%.

[0036] Bismuth isooctanoate: CAS No. 67874-71-9, bismuth content 20%-28%.

[0037] Modified azodicarbonamide: CAS No. 123-77-3, decomposition temperature 195℃-205℃, average particle size (D50) 3μm-5μm.

[0038] Ethylene-vinyl acetate copolymer: CAS No. 24937-78-8, vinyl acetate mass fraction 18%-28%, melting point 75℃-85℃.

[0039] Low melting point thermoplastic polyurethane: polyester type, melting point 80℃-90℃.

[0040] Antioxidant 1010 and carbodiimide hydrolysis stabilizer are both commercially available conventional industrial-grade additives.

[0041] Preparation Example 1: This preparation example provides a method for preparing sustained-release foaming masterbatch A1, including the following steps: Accurately weigh 30 parts by weight of modified azodicarbonamide and 70 parts by weight of ethylene-vinyl acetate copolymer; add the ethylene-vinyl acetate copolymer to a mixer and plasticize at 95℃-105℃ for 1-2 minutes, then add the modified azodicarbonamide and continue mixing at 105℃-115℃ for 3-5 minutes until the material is macroscopically dispersed and uniform; extrude the mixed material through a single screw extruder at 100℃-110℃ to granulate, air-cool and dry, and seal and package to obtain slow-release foaming masterbatch A1.

[0042] Preparation Example 2: This preparation example provides a method for preparing sustained-release foaming masterbatch A2, including the following steps: Accurately weigh 35 parts by weight of modified azodicarbonamide and 65 parts by weight of ethylene-vinyl acetate copolymer; add the ethylene-vinyl acetate copolymer to a mixer and plasticize at 95℃-105℃ for 1-2 minutes, then add the modified azodicarbonamide and continue mixing at 105℃-115℃ for 3-5 minutes until the material is macroscopically dispersed and uniform; extrude the mixed material through a single screw extruder at 100℃-110℃ to granulate, air-cool and dry, and seal and package to obtain slow-release foaming masterbatch A2.

[0043] Preparation Example 3: This preparation example provides a method for preparing sustained-release foaming masterbatch A3, including the following steps: Accurately weigh 40 parts by weight of modified azodicarbonamide and 60 parts by weight of low-melting-point thermoplastic polyurethane; add the low-melting-point thermoplastic polyurethane to a mixer and plasticize at 100℃-110℃ for 1-2 minutes, then add the modified azodicarbonamide and continue mixing at 110℃-120℃ for 3-5 minutes until the material is macroscopically dispersed and uniform; extrude the mixed material through a single-screw extruder at 105℃-115℃ to granulate, air-cool and dry, and seal and package to obtain slow-release foaming masterbatch A3.

[0044] Preparation Example 4: This preparation example provides a method for preparing a wear-resistant premixed liquid B1 containing a catalyst, including the following steps: Under normal temperature and pressure and relative humidity below 50%, 0.1 parts by weight of bismuth isooctanoate were added to 100 parts by weight of hydroxyl-terminated polydimethylsiloxane that had been pre-vacuum dried; the mixture was stirred for 20-30 minutes at 300-500 rpm using a mechanical stirrer with a sealed cap until a homogeneous and transparent mixed solution was formed. After vacuum degassing, the mixture was sealed and stored to obtain a wear-resistant premixed solution B1 containing the catalyst.

[0045] Preparation Example 5: This preparation example provides a method for preparing a catalyst-containing wear-resistant premixed liquid B2, including the following steps: Under normal temperature and pressure and relative humidity below 50%, 0.2 parts by weight of bismuth isooctanoate were added to 100 parts by weight of hydroxyl-terminated polydimethylsiloxane that had been pre-vacuum dried. The mixture was stirred for 20-30 minutes at 300-500 rpm using a mechanical stirrer with a sealed cap until a homogeneous and transparent mixed solution was formed. After vacuum degassing, the solution was sealed and stored to obtain a wear-resistant premixed solution B2 containing the catalyst.

[0046] Example 1: This embodiment provides a method for preparing lightweight, flexible, and wear-resistant electrical equipment connection cables, including the following steps: (1) Mixing of main feed: Accurately weigh 100 parts by weight of polyester thermoplastic polyurethane elastomer, 5 parts by weight of styrene-acrylonitrile copolymer, 1.5 parts by weight of maleic anhydride grafted polyolefin elastomer, 2.0 parts by weight of end-capped isophorone diisocyanate, 0.5 parts by weight of antioxidant 1010 and 0.3 parts by weight of carbodiimide hydrolysis stabilizer; put the above raw materials into a high-speed mixer and mix at low speed for 3 minutes. The resulting mixture is added to the main feed port of the twin-screw extruder as solid component A. (2) Liquid injection: Accurately weigh 4.0 parts by weight of the abrasion-resistant premixed liquid B1 containing the catalyst obtained in Example 4, as liquid component B, and inject it into the third barrel of the twin-screw extruder through a liquid metering pump; (3) Side feed addition: Accurately weigh 2.0 parts by weight of the slow-release foaming masterbatch A1 obtained in Preparation Example 1, and use it as side feed component C, and add it to the 7th barrel of the twin-screw extruder through the side feeder; (4) Reactive extrusion: Reactive extrusion was carried out using a co-rotating twin-screw extruder with a length-to-diameter ratio of 48:1. The screw speed was set to 300 rpm. The temperatures of each zone of the extruder were set as follows: Zones 1-3 (melt dispersion section) were 145℃, 150℃, and 155℃; Zones 4-6 (catalytic grafting section) were 165℃, 170℃, and 170℃; Zones 7-8 (side feeding mixing section) were 175℃ and 180℃; Zones 9-11 (foaming reaction section) were 195℃, 200℃, and 200℃; and the die head temperature was 185℃. (5) Molding and cooling: The extruded melt is coated on the surface of the copper conductor by the cross die head, and then cooled and shaped by three water tanks at 60℃, 40℃ and 20℃. The lightweight, flexible and wear-resistant electrical equipment connection cable is obtained by traction and winding.

[0047] Example 2: This embodiment provides a method for preparing lightweight, flexible, and wear-resistant electrical equipment connection cables, including the following steps: (1) Main feed mixing: Accurately weigh 100 parts by weight of polyester thermoplastic polyurethane elastomer, 3 parts by weight of styrene-acrylonitrile copolymer, 0.5 parts by weight of maleic anhydride grafted polyolefin elastomer, 1.0 parts by weight of end-capped isophorone diisocyanate, 0.5 parts by weight of antioxidant 1010 and 0.3 parts by weight of carbodiimide hydrolysis stabilizer; mix in a high-speed mixer for 3 minutes, and add the resulting mixture as solid component A to the main feed port of the twin-screw extruder; (2) Liquid injection: Accurately weigh 2.0 parts by weight of the abrasion-resistant premixed liquid B1 containing the catalyst obtained in Preparation Example 4, as liquid component B, and inject it into the third barrel of the twin-screw extruder through a liquid metering pump; (3) Side feed addition: Accurately weigh 1.5 parts by weight of the slow-release foaming masterbatch A2 obtained in Preparation Example 2, and use it as side feed component C, and add it to the 7th barrel of the twin-screw extruder through the side feeder; (4) Reactive extrusion: Reactive extrusion was carried out using a co-rotating twin-screw extruder with a length-to-diameter ratio of 48:1. The screw speed was set to 280 rpm. The temperatures of each zone of the extruder were set as follows: Zones 1-3: 140℃, 145℃, 150℃; Zones 4-6: 165℃, 165℃, 170℃; Zones 7-8: 170℃, 175℃; Zones 9-11: 195℃, 195℃, 200℃; Die head temperature: 180℃. (5) Molding and cooling: The process steps are the same as in Example 1.

[0048] Example 3: This embodiment provides a method for preparing lightweight, flexible, and wear-resistant electrical equipment connection cables, including the following steps: (1) Main feed mixing: Accurately weigh 100 parts by weight of polyester thermoplastic polyurethane elastomer, 8 parts by weight of styrene-acrylonitrile copolymer, 2.5 parts by weight of maleic anhydride grafted polyolefin elastomer, 3.0 parts by weight of end-capped isophorone diisocyanate, 0.5 parts by weight of antioxidant 1010 and 0.3 parts by weight of carbodiimide hydrolysis stabilizer; mix in a high-speed mixer for 5 minutes, and add the resulting mixture as solid component A to the main feed port of the twin-screw extruder; (2) Liquid injection: Accurately weigh 6.0 parts by weight of the abrasion-resistant premixed liquid B2 containing the catalyst obtained in Preparation Example 5, as liquid component B, and inject it into the third barrel of the twin-screw extruder through a liquid metering pump; (3) Side feed addition: Accurately weigh 3.0 parts by weight of the slow-release foaming masterbatch A3 obtained in Preparation Example 3, and use it as side feed component C, and add it to the 7th barrel of the twin-screw extruder through the side feeder; (4) Reactive extrusion: Reactive extrusion was carried out using a co-rotating twin-screw extruder with a length-to-diameter ratio of 52:1. The screw speed was set to 350 rpm. The temperatures of each zone of the extruder were set as follows: Zones 1-3: 150℃, 155℃, 160℃; Zones 4-6: 170℃, 175℃, 175℃; Zones 7-8: 180℃, 185℃; Zones 9-11: 200℃, 205℃, 205℃; Die head temperature: 190℃. (5) Molding and cooling: The process steps are the same as in Example 1.

[0049] Example 4: This embodiment provides a method for preparing lightweight, flexible, and wear-resistant electrical equipment connection cables, including the following steps: (1) Mixing of main feed: The raw material ratio is the same as in Example 1, and it is added to the main feed port as solid component A; (2) Liquid injection: Weigh 5.0 parts by weight of the wear-resistant premixed liquid B1 containing the catalyst obtained in Preparation Example 4 and inject it into the third cylinder as liquid component B; (3) Side feed addition: Weigh 2.5 parts by weight of the slow-release foaming masterbatch A3 obtained in Preparation Example 3 and add it to the 7th cylinder as side feed component C; (4) Reactive extrusion: The screw speed was set to 320 rpm; the temperature parameters were adjusted to be biased towards the low temperature window to verify the lower limit of the process: the temperature of zones 1-3 was 145℃, 150℃, and 155℃; the temperature of zones 4-6 was 165℃, 168℃, and 170℃; the temperature of zones 7-8 was 175℃ and 178℃; the temperature of zones 9-11 was 192℃, 195℃, and 195℃; the die head temperature was 182℃. (5) Molding and cooling: The process steps are the same as in Example 1.

[0050] Example 5: This embodiment provides a method for preparing lightweight, flexible, and wear-resistant electrical equipment connection cables, including the following steps: (1) Mixing of main feed: The raw material ratio is the same as in Example 1, and it is added to the main feed port as solid component A; (2) Liquid injection: The raw material ratio is the same as in Example 1, and it is injected into the third cylinder as liquid component B; (3) Side feeding addition: The raw material ratio is the same as in Example 1, and it is added to the 7th cylinder as side feeding component C; (4) Reactive extrusion: The screw speed was set to 300 rpm; the temperature parameters were adjusted to be close to the high temperature window to verify the upper limit of the process: the temperature of zones 1-3 was 150℃, 155℃, and 160℃; the temperature of zones 4-6 was 172℃, 175℃, and 178℃; the temperature of zones 7-8 was 182℃ and 185℃; the temperature of zones 9-11 was 202℃, 205℃, and 205℃; the die head temperature was 190℃. (5) Molding and cooling: The process steps are the same as in Example 1.

[0051] Example 6: This embodiment provides a method for preparing lightweight, flexible, and wear-resistant electrical equipment connection cables, including the following steps: (1) Mixing of main feed: The raw material ratio is the same as in Example 1, and it is added to the main feed port as solid component A; (2) Liquid injection: Accurately weigh 4.0 parts by weight of the wear-resistant premixed liquid B2 containing the catalyst obtained in Preparation Example 5 (high catalyst activity) and inject it into the third cylinder as liquid component B; (3) Side feed addition: Accurately weigh 2.0 parts by weight of the slow-release foaming masterbatch A3 (TPU carrier) obtained in Preparation Example 3 and add it to the 7th cylinder as side feed component C; (4) Reactive extrusion: A co-rotating twin-screw extruder with a length-to-diameter ratio of 48:1 was used, and the screw speed was set to 300 rpm; the temperature settings of each temperature zone were the same as in Example 1; (5) Molding and cooling: The process steps are the same as in Example 1.

[0052] Comparative Example 1: Compared with Example 1, the difference is that maleic anhydride-grafted polyolefin elastomer, end-capped isophorone diisocyanate and catalyst-containing wear-resistant premix B1 were not added, and only slow-release foaming masterbatch A1 was added at the side feed point, and the rest were the same.

[0053] Comparative Example 2: Compared with Example 1, the difference is that no capped isophorone diisocyanate was added to the main feed component A, while the rest are the same.

[0054] Comparative Example 3: Compared with Example 1, the difference is that the maleic anhydride-grafted polyolefin elastomer in the main feed component A is replaced with an equal amount of ungrafted maleic anhydride ethylene-octene copolymer, and all other aspects are the same.

[0055] Comparative Example 4: Compared with Example 1, the difference is that bismuth isooctanoate catalyst was not added to liquid component B, and an equal amount of hydroxyl-terminated polydimethylsiloxane was used directly, while the rest are the same.

[0056] Comparative Example 5: Compared with Example 1, the difference is that the feeding order is changed. All the slow-release foaming masterbatch A1 is mixed with solid component A in step (1) and then added through the main feed port. The side feeding operation in step (3) is cancelled. All the rest are the same.

[0057] Comparative Example 6: Compared with Example 1, the difference is that the modified azodicarbonamide in the slow-release foaming masterbatch A1 is replaced with an equal amount of sodium bicarbonate endothermic foaming agent, and all other aspects are the same.

[0058] Test Example 1: Test objective: To verify the performance of the cable materials prepared in each embodiment and comparative example in terms of density, hardness and basic mechanical properties, to evaluate whether they meet the industry standards for cables for electrical equipment, and to verify the impact of the foaming lightweight process on the structural strength of the materials.

[0059] Experimental steps: 1. Sample preparation: The cable sheath materials prepared in Examples 1 to 6 and Comparative Examples 1 to 6 were peeled off, or the extruded granulated particles were injection molded into standard test specimens at 190°C using an injection molding machine; the injection molded specimens included dumbbell-shaped strips for tensile testing and block specimens for hardness testing; all specimens were conditioned for 24 hours in an environment with a temperature of 23±2°C and a relative humidity of 50±5% before testing.

[0060] 2. Density test: The density of the material is tested by immersion method according to ASTM D792 standard; a high-precision electronic densitometer is used to record the mass of the sample in air and the mass in distilled water, and the density value is calculated; 5 samples are tested for each group of samples, and the arithmetic mean is taken.

[0061] 3. Hardness test: According to ASTM D2240 standard, a Shore A hardness tester is used for testing; place the sample on a horizontal platform, press the indenter vertically into the sample surface, hold for 1 second and then read the value; select 5 different positions for each sample for measurement and take the arithmetic mean.

[0062] 4. Tensile property test: According to ASTM D412 standard, the dumbbell-shaped specimens were subjected to tensile tests using a universal testing machine; the tensile speed was set to 500 mm / min, the maximum load and elongation at the time of specimen breakage were recorded, and the tensile strength and elongation at break were calculated; 5 parallel specimens were tested for each group of samples, and the arithmetic mean was taken.

[0063] The experimental data are shown in Table 1: Table 1: Test results of physical and mechanical properties of each embodiment and comparative example Results Analysis and Conclusions: Based on Table 1 and... Figure 1 The data shows that the density of samples in Examples 1 to 6 was controlled at 0.73 g / cm³. 3 Up to 0.83 g / cm 3 Between these values, compared to approximately 1.20 g / cm³ of conventional solid TPU material. 3 The density achieves a significant weight reduction effect, while the hardness is maintained within a suitable range of 74A to 79A, meeting the dual requirements of cable sheath for flexibility and support.

[0064] Example 1 exhibited a tensile strength of 18.4 MPa and an elongation at break of 485.2%, while Comparative Example 3, without the addition of maleic anhydride-grafted polyolefin elastomer, showed a tensile strength of only 11.2 MPa and a significantly reduced elongation at break of 285.9%. This marked difference validates the effectiveness of the in-situ conversion mechanism of foaming byproducts. In Comparative Example 3, the ammonia gas produced by the decomposition of azodicarbonamide could not be captured, and the free ammonia gas may have exacerbated the degradation of the polyurethane matrix or disrupted the continuity of the cell walls, leading to a sharp decline in mechanical properties. Conversely, in Example 1, the maleic anhydride groups successfully captured the ammonia gas and converted it into an imide structure. The in-situ generated modified polyolefin acted as a compatibilizer, enhancing the interfacial bonding between the styrene-acrylonitrile copolymer reinforcing phase and the polyurethane matrix, thus maintaining high material strength despite the reduction in cross-sectional area caused by foaming.

[0065] Compared to Example 1, which uses an endothermic foaming agent, Comparative Example 6, although avoiding the generation of ammonia, still has a tensile strength of 16.2 MPa, lower than that of Example 1. This indicates that the present invention does not simply eliminate the negative effects of ammonia, but rather transforms ammonia into a beneficial interfacial compatibilizer through a chemical interlocking strategy, turning waste into treasure and further improving the overall performance of the material.

[0066] Furthermore, Comparative Example 5, which uses a main feeding method to add foaming agent, has a density as high as 0.943 g / cm³. 3 The results were significantly higher than in Example 1. This confirms the necessity of a shear-heat isolation mechanism. In the main feeding process, the foaming agent underwent an excessively long thermal process and strong shear action, causing some of the foaming agent to decompose prematurely at the front of the extruder. The gas escaped from the feed port or vent, failing to be effectively retained in the melt to form cells. This not only reduced the foaming efficiency but also resulted in the final product's density failing to meet the expected lightweight target. Example 1, through a staged side-feeding process, ensured that the foaming agent decomposed only at the screw end, achieving a uniform and sufficient foaming effect in conjunction with appropriate melt strength.

[0067] Test Example 2: Test objective: By comparing the performance differences of cable materials with different chemical structure designs in terms of wear, friction coefficient and aging precipitation, this test aims to verify the effectiveness of kinetic catalytic bias technology in achieving chemical grafting of polysiloxane and polyurethane matrix, and its impact on the long-term service stability of the materials.

[0068] Experimental steps: 1. Sample preparation: The cable sheath materials prepared in Example 1, Comparative Example 2 and Comparative Example 4 were selected and injection molded into cylindrical samples with a diameter of 16 mm and a thickness of 6 mm for DIN abrasion test, and square samples with a size of 63.5 mm × 63.5 mm × 3 mm for friction coefficient and aging test; all samples were placed in a standard laboratory environment for 48 hours before testing.

[0069] 2. DIN Abrasion Volume Test: According to DIN 53516 standard, a rotary roller abrasion tester is used for testing; the specified sandpaper is laid on the roller surface, the load is set to 10N, and the sample is moved laterally on the sandpaper without slippage, with an abrasion stroke of 40m; the sample mass is weighed before and after the test, and the volume abrasion amount is calculated by combining the abrasion amount of the standard adhesive and the sample density; 3 samples are tested in each group.

[0070] 3. Surface friction coefficient test: According to ASTM D1894 standard, the dynamic friction coefficient of the sample surface is tested using a friction coefficient measuring instrument; the sample is fixed on a horizontal test platform, a slider covered with the same material is placed on the sample, the slider is pulled at a speed of 150 mm / min, the friction force during the sliding process is recorded and the dynamic friction coefficient is calculated; each group of tests is performed 5 times.

[0071] 4. Accelerated aging precipitation test: Place the weighed square sample in a constant temperature and humidity chamber, set the environmental conditions to 85℃ high temperature and 85% relative humidity, and continue aging for 168 hours; after removing the sample and cooling it to room temperature, observe whether there is liquid precipitation or whitening on the surface, and score the surface greasiness (1 point indicates that the surface is dry and there is no precipitation, and 5 points indicates that the surface is severely greasy and there are droplets); then use filter paper soaked in anhydrous ethanol to repeatedly wipe the surface of the sample to remove the precipitates, vacuum dry it and weigh it again, and calculate the mass loss rate to quantify the degree of precipitation.

[0072] The experimental data are shown in Table 2: Table 2: Test results of wear resistance and exudation performance of the examples and comparative examples Results Analysis and Conclusions: Based on Table 2 and... Figure 2 According to the data, the DIN wear volume in Example 1 was only 34.2 mm. 3 Furthermore, after rigorous high-temperature and high-humidity aging, the mass loss rate was only 0.08%, and the surface score was 1, demonstrating excellent wear resistance and chemical stability. This indicates that, under the catalysis of bismuth isooctanoate, hydroxyl-terminated polydimethylsiloxane was successfully grafted onto the thermoplastic polyurethane backbone via end-capped isophorone diisocyanate. The formed urethane bonds firmly anchor the organosilicon segments to the matrix surface, providing both durable low-friction properties and preventing small molecule migration.

[0073] Comparative Example 2, without the addition of a chemical bridging agent, had a lower coefficient of dynamic friction (0.19), but a wear volume as high as 128.5 mm. 3 Furthermore, the quality loss rate after aging is as high as 2.45%, and the surface is severely oily (score 5). This is because the silicone molecules that have not undergone chemical reaction are only physically dispersed in the matrix. Due to their thermodynamic incompatibility with polyurethane, the silicone molecules tend to migrate to the surface. Although they can provide lubrication initially, as friction continues, the surface silicone is rapidly lost and cannot be replenished, leading to a loss of wear resistance. At the same time, severe precipitation contaminates the cable surface.

[0074] Comparative Example 4, without catalyst, had a wear volume of 86.7 mm. 3The concentration of the compound was between that of Example 1 and Comparative Example 2, with significant precipitation (1.12%). In the absence of a selective catalyst, the reaction rate of the decapped isocyanate with the terminal hydroxyl-terminated polydimethylsiloxane after decapsulation was not advantageous. Some isocyanate may react with other active hydrogens in the system (such as hydrolysis products or matrix end groups), or the terminal hydroxyl-terminated polydimethylsiloxane may undergo competitive esterification with the maleic anhydride graft. This kinetic nonselectivity resulted in only a portion of the organosilicon being effectively grafted. The remaining free organosilicon not only failed to provide durable wear protection but also became a plasticizer in the system, reducing the bulk strength of the material and leading to precipitation. This result strongly confirms the decisive role of the kinetic catalytic bias mechanism in achieving precise reaction control in complex multi-component systems.

[0075] Test Example 3: Test objective: To investigate the chemical capture ability of maleic anhydride-grafted polyolefin elastomers for ammonia, a decomposition product of azodicarbonamide foaming agent, and the influence of this in-situ reaction product on the interfacial bonding strength and resilience of microporous foamed materials, thereby verifying the effectiveness of the in-situ conversion mechanism of foaming byproducts.

[0076] Experimental steps: 1. Sample preparation: Sheath samples were cut from the cables obtained in Example 1, Comparative Example 1, Comparative Example 3 and Comparative Example 6; for the right-angle tear strength test, the sheath was cut open and flattened, and then cut into right-angled samples (C-type) without cuts according to ASTM D624 standard; for the compression set test, the same material was stacked to the specified thickness to make a cylindrical sample with a diameter of 13 mm and a height of 6 mm; for the odor test, the cable sheath was chopped into particles with a particle size of about 3 mm.

[0077] 2. Right-angle tear strength test: Using an electronic tensile testing machine equipped with pneumatic clamps, the right-angled specimen is stretched at a rate of 500 mm / min until it breaks; the maximum load is recorded, and the tear strength is calculated based on the specimen thickness; 5 parallel specimens are tested in each group, and the arithmetic mean is taken.

[0078] 3. Compression set test: According to ASTM D395 Method B, place the cylindrical specimen between two parallel steel plates and use a limiter to compress the specimen to 75% of its original height (i.e., the compression rate is 25%); place the fixture and the specimen in a 70°C hot air aging chamber for 22 hours; remove it and unload it immediately, let it stand at room temperature for 30 minutes, measure the height after recovery, and calculate the compression set rate.

[0079] 4. Residual ammonia odor level test: conducted according to VDA 270 C3 standard; accurately weigh 50g of chopped sample and place it in a 1L standard glass sealed container, then seal the container; place the sealed container in an 80℃ constant temperature oven for 2 hours; after removal, cool to 60℃, and have 3 professionally trained odor evaluators open the container, smell, and score the sample; the scoring standard uses a 6-point system, where 1 point represents no odor, 3 points represent a noticeable but not pungent odor, and 6 points represent an unbearable pungent odor; take the arithmetic mean of the 3 scores and round it to 0.5.

[0080] The experimental data are shown in Table 3: Table 3: Test Results of Interfacial Strength and Odor Level of Foaming System Results Analysis and Conclusions: Based on Table 3 and... Figure 3 According to the data, Example 1, while maintaining a low odor rating (2.0), achieved a right-angle tear strength of 78.4 kN / m and a compression set of only 28.5%. In contrast, Comparative Example 1, without maleic anhydride-grafted polyolefin elastomer, and Comparative Example 3, using ungrafted polyolefin elastomer, had odor ratings of 4.5 and 5.0, respectively, and generally had tear strengths below 55 kN / m and compression set rates exceeding 45%.

[0081] Comparative Example 3 data shows that simply physically blending ungrafted polyolefin elastomers cannot effectively capture the ammonia gas produced by the decomposition of azodicarbonamide, resulting in a strong, pungent odor remaining in the final product. Furthermore, due to the polarity difference and lack of chemical bonding between the polyolefin phase and the thermoplastic polyurethane / styrene-acrylonitrile copolymer matrix, the interfacial bonding between the two phases is weak. During the foaming process, bubble growth further weakens the matrix continuity, making the material prone to tearing along the interface under stress. Moreover, under high-temperature compression, the cell walls are prone to collapse and slippage, resulting in a high compression set.

[0082] The comparison between Example 1 and Comparative Example 6 directly confirms the unique advantages of the in-situ transformation mechanism of foaming byproducts. Comparative Example 6 used an endothermic foaming agent that does not produce ammonia. Although it had the lowest odor rating (1.5), its right-angle tear strength (64.7 kN / m) was significantly lower than that of Example 1. This indicates that the high strength of Example 1 is not solely due to the elimination of the corrosive effect of ammonia, but more fundamentally because ammonia participated in the chemical construction as a reactant. In Example 1, the maleic anhydride groups reacted with ammonia to generate amide or imide structures, significantly increasing the polarity of the polyolefin elastomer and transforming it in situ into a highly efficient interfacial compatibilizer. This in-situ generated compatibilizer enhances the toughness of the cell walls and the adhesion of the multiphase interface, enabling the material to achieve lightweight while maintaining superior physical and mechanical properties compared to Comparative Example 6, which used an expensive and environmentally friendly foaming agent. The lower compression set of Example 1 also confirms that this chemical cross-linking network enhances the resilience of the microporous structure.

[0083] Test Example 4: Test objective: To investigate the effects of different feeding methods and process parameter settings on melt pressure fluctuations, cable dimensional accuracy, and surface appearance quality during continuous extrusion, and to verify the engineering necessity of side-feeding technology in isolating shear heat and ensuring the controllability of the chemical foaming process.

[0084] Experimental steps: 1. Continuous extrusion experiment: On the same type of twin-screw extruder, continuous extrusion production was carried out according to the process conditions set in Example 1, Example 4, Example 5 and Comparative Example 5 respectively; each group of experiments continued to run until the length of the produced cable reached 1000 meters; during the process, the screw speed and traction speed were kept constant and no human intervention or adjustment was made.

[0085] 2. Melt pressure monitoring: Pressure data is collected in real time by a Dynisco melt pressure sensor installed at the extruder head; the sampling frequency is 1Hz (i.e., once per second); the highest and lowest pressure values ​​are recorded throughout the steady-state extrusion process, and the pressure fluctuation range is calculated.

[0086] 3. Diameter consistency measurement: Use an online laser diameter gauge or a high-precision digital caliper to measure the outer diameter of the cable at fixed points every 100 meters; record the values ​​of 10 measurement points and calculate their standard deviation. The smaller the value, the higher the dimensional stability.

[0087] 4. Surface quality statistics: Set up a visual inspection station on the production line and conduct a re-inspection after winding; count the number of defects such as large bubbles, holes or surface flow marks with a diameter greater than 0.5mm that appear within every 100 meters of cable length, and calculate the average defect density.

[0088] The experimental data are shown in Table 4: Table 4: Statistical Results of Process Stability and Cable Appearance Quality Results Analysis and Conclusions: Based on Table 4 and... Figure 4 According to the data, Example 1 demonstrated excellent process stability during continuous production, with a head pressure fluctuation range of only 0.35 MPa, a cable diameter standard deviation controlled at 0.024 mm, and an extremely low surface defect density (an average of 0.4 defects per 100 meters). In contrast, Comparative Example 5, which used a main feeding process, exhibited a head pressure fluctuation as high as 4.25 MPa, a diameter standard deviation increased to 0.187 mm, and frequent surface defects, with an average of 38.5 punctures or large bubbles per 100 meters.

[0089] The process instability observed in Comparative Example 5 directly confirms the crucial role of the shear-heat isolation mechanism. In the main feeding process, the azodicarbonamide foaming agent, along with the resin matrix, undergoes solid conveying, melting, and mixing processes in the front section of the extruder. Due to the intense frictional heat generated by the screw shearing, the material temperature exceeds the decomposition temperature of the foaming agent before the pressure build-up zone. The large amount of gas released prematurely flows back into the barrel due to the pressure gradient, causing discontinuous melt delivery and triggering extrusion surge. This pressure fluctuation directly leads to inconsistent cable outer diameter, and the prematurely formed bubbles rupture and merge when passing through the high-shear zone, ultimately resulting in dense large bubbles and skin breakage on the product surface.

[0090] Example 1 involves adding the foaming agent masterbatch from the seventh barrel side feed port, thus avoiding the high-temperature shearing process at the beginning. The foaming agent only undergoes brief heating and mixing at the screw end and die head, ensuring that the decomposition reaction mainly occurs during the pressure release stage after the die exits. This spatial and temporal isolation guarantees the consistency of nucleation and the smoothness of melt delivery.

[0091] Furthermore, the data from Examples 4 and 5 indicate that the process has a wide operating window. Example 4 used a relatively low temperature setting; although the increased melt viscosity led to a slight increase in pressure fluctuation to 0.52 MPa, the product quality remained acceptable. Example 5 used a relatively high temperature setting; although this resulted in a slight increase in surface defects (2.6 defects / 100 μm), the overall stability was far superior to Comparative Example 5. This demonstrates that the side-feeding process effectively reduces the formulation's sensitivity to temperature, making it more suitable for large-scale continuous industrial production.

[0092] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A lightweight, flexible, wear-resistant electrical equipment connection cable, characterized in that, The sheath of the connecting cable is made of a raw material comprising the following parts by weight: Polyester-based thermoplastic polyurethane elastomer: 100 parts; Styrene-acrylonitrile copolymer: 3-8 parts; Maleic anhydride-grafted polyolefin elastomer: 0.5-2.5 parts; Capped isophorone diisocyanate: 1.0-3.0 parts; Abrasion-resistant premix containing catalyst: 2.0-6.0 parts; Sustained-release foaming masterbatch: 1.5-3.0 parts; And functional additives: 0.8-1.5 parts; wherein, the wear-resistant premix containing catalyst contains hydroxyl-terminated polydimethylsiloxane and bismuth isooctanoate catalyst, the slow-release foaming masterbatch contains modified azodicarbonamide foaming agent and carrier resin, and the functional additives contain antioxidant and carbodiimide hydrolysis stabilizer.

2. The lightweight, flexible, wear-resistant electrical equipment connection cable according to claim 1, characterized in that, The weight parts of the raw materials are: Polyester-based thermoplastic polyurethane elastomer: 100 parts; Styrene-acrylonitrile copolymer: 5 parts; Maleic anhydride-grafted polyolefin elastomer: 1.5 parts; Capped isophorone diisocyanate: 2.0 parts; Abrasion-resistant premix containing catalyst: 4.0 parts; Sustained-release foaming masterbatch: 2.0 parts; Functional additives: 0.8 parts.

3. The lightweight, flexible, wear-resistant electrical equipment connection cable according to claim 1, characterized in that, In the wear-resistant premix containing the catalyst, the amount of bismuth isooctanoate catalyst added is 0.1-0.2 parts by weight relative to 100 parts by weight of hydroxyl-terminated polydimethylsiloxane; the kinematic viscosity of the hydroxyl-terminated polydimethylsiloxane at 25°C is 5000-10000 cSt. In the slow-release foaming masterbatch, the weight ratio of modified azodicarbonamide foaming agent to carrier resin is 30-40:60-70; the carrier resin is ethylene-vinyl acetate copolymer or low-melting-point thermoplastic polyurethane.

4. The lightweight, flexible, wear-resistant electrical equipment connection cable according to claim 1, characterized in that, The maleic anhydride-grafted polyolefin elastomer uses ethylene-octene copolymer as the matrix, and the maleic anhydride grafting rate is 0.8%-1.2%. The capped isophorone diisocyanate is caprolactam-capped, and the decapping temperature is 150℃-160℃.

5. A method for preparing a lightweight, flexible, wear-resistant electrical equipment connecting cable according to any one of claims 1-4, characterized in that, Includes the following steps: S1. The polyester thermoplastic polyurethane elastomer, styrene-acrylonitrile copolymer, maleic anhydride grafted polyolefin elastomer, end-capped isophorone diisocyanate and functional additives are mixed evenly and added as solid components from the main feed port of the twin-screw extruder. S2. The wear-resistant premix containing the catalyst is injected into the twin-screw extruder as a liquid component, and the injection position is located after the solid component has melted; S3. The slow-release foaming masterbatch is added as a side feed component from the side feed port of the twin-screw extruder, the side feed port being located downstream of the liquid component injection position; S4. Control the temperature distribution of the twin-screw extruder so that the material successively undergoes the processes of melting and dispersion, catalytic grafting, side feeding and mixing, and foaming reaction before being extruded through the die head; S5. The extruded melt is coated onto the surface of the conductor and then cooled and shaped by a multi-stage water bath gradient.

6. The method for preparing the lightweight, flexible, wear-resistant electrical equipment connecting cable according to claim 5, characterized in that, In step S2, the liquid component is injected into the third barrel of the twin-screw extruder; In step S3, the side-feed component is added from the seventh barrel of the twin-screw extruder; The length-to-diameter ratio of the twin-screw extruder is ≥48:

1.

7. The method for preparing the lightweight, flexible, wear-resistant electrical equipment connecting cable according to claim 5, characterized in that, In step S4, the temperature setting of the twin-screw extruder is as follows: Zones 1-3 are 140℃-160℃; Zones 4-6 have a temperature range of 165℃-178℃; Zones 7 and 8 have a temperature range of 170℃ to 185℃. Zones 9-11 have a temperature range of 192℃-205℃; The head temperature is 180℃-190℃.

8. The method for preparing the lightweight, flexible, wear-resistant electrical equipment connecting cable according to claim 5, characterized in that, Prior to step S2, the catalyst-containing wear-resistant premix is ​​prepared by the following method: Bismuth isooctanoate was added to hydroxyl-terminated polydimethylsiloxane that had been vacuum dried in an environment with a relative humidity of less than 50%, stirred until homogeneous and transparent, and then degassed under vacuum.

9. The method for preparing the lightweight, flexible, wear-resistant electrical equipment connecting cable according to claim 5, characterized in that, Prior to step S3, the sustained-release foaming masterbatch is prepared by the following method: The carrier resin is plasticized in a mixer, and modified azodicarbonamide is added. The mixture is then kneaded at 105℃-120℃ until it is evenly dispersed, and then extruded and granulated at 100℃-115℃. The temperature of the preparation process is lower than the decomposition temperature of the modified azodicarbonamide.

10. The method for preparing the lightweight, flexible, wear-resistant electrical equipment connecting cable according to claim 5, characterized in that, In step S4, the screw speed of the twin-screw extruder is set to 280-350 rpm.

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