Ozone-resistant, high abrasion-resistant rubber-sheathed cable

Abstract

The application discloses an ozone-resistant high-wear-resistance rubber-sheathed cable and belongs to the technical field of cables. The cable structure comprises, from inside to outside, a conductor, an insulation layer and an outer sheath. The outer sheath material comprises, in terms of mass parts, the following raw materials: a chlorinated polyethylene matrix 80-100 parts, a polymer composition 12-20 parts, a functionalized halloysite nanotube composite 15-35 parts, a reinforcing agent 20-40 parts, a plasticizer 10-20 parts, an antioxidant 2-4 parts, a cross-linking system 5-7 parts and a lubricant 2-4 parts. The functionalized halloysite nanotube composite not only solves the inherent problems of halloysite nanotube, such as difficult dispersion in a rubber matrix and weak interface combination, but also releases the antioxidant through the unique nanotube cavity structure and forms a multiple synergistic network with the polymer composition and the chlorinated polyethylene matrix. The finally prepared cable outer sheath significantly improves the wear resistance and exhibits excellent ozone aging resistance.

Description

Technical Field

[0001] This invention belongs to the field of cable technology, specifically relating to an ozone-resistant and highly abrasion-resistant rubber-sheathed cable. Background Technology

[0002] Rubber-sheathed cables are widely used in complex and variable environments such as ports, mines, construction sites, and chemical plants due to their excellent flexibility and mobility. These applications not only require cables to withstand frequent bending, dragging, and friction, but also often expose them to the corrosive effects of high and low temperatures, oil contamination, humidity, salt spray, and high concentrations of ozone. Ozone, in particular, as a strong oxidizing gas, can react with the unsaturated double bonds in rubber molecules even at extremely low concentrations, causing surface cracking and hardening, ultimately leading to the loss of mechanical and electrical properties—a process known as "ozone cracking."

[0003] To improve abrasion resistance, a common approach is to use large amounts of traditional reinforcing fillers such as high-abrasion-resistant carbon black or silica. However, high filler content leads to new problems such as high mixing energy consumption, high heat generation in the rubber compound, and deterioration of flexibility and processing performance. Furthermore, the microstructure of conventional fillers is spherical or quasi-spherical, and their reinforcement of the rubber matrix and crack propagation resistance mainly rely on the filler's "hydrodynamic effect" and "network structure." When facing microscale abrasion and ozone-induced microcrack propagation, their "pinning" and "deflecting" effects on cracks are limited. More importantly, there is often a trade-off between the ozone aging resistance, abrasion resistance, oil resistance, mechanical strength, and flexibility of cables. For example, increasing the crosslinking density or using saturated main-chain rubber to improve ozone resistance may lead to cable hardening and decreased flexural fatigue resistance; while using large amounts of rigid fillers for abrasion resistance may sacrifice elongation at break and resistance to oil swelling.

[0004] Chinese patent CN118599229A discloses a sheath material for rubber-sheathed cables, using a compound of closed-cell perlite, carbon black, and rubber powder as a modified filler to enhance the wear resistance and aging resistance of the sheath material, but its ozone resistance is not significantly improved. Chinese patent CN119019771A discloses a high-wear-resistant rubber-sheathed cable for mining, using modified garnet powder and molybdenum disulfide to improve wear resistance and aging resistance, but the base rubber uses a combination of styrene-butadiene rubber and nitrile rubber, resulting in limited ozone resistance. Chinese patent CN121565544A discloses a rubber-sheathed cable using a polymeric composition of hydrogenated styrene-isoprene block copolymer and acrylonitrile-butadiene copolymer, improving oil resistance and high / low temperature resistance, but there is still room for improvement in wear resistance and ozone resistance.

[0005] In summary, how to synergistically resolve the aforementioned contradictions within a single system through innovative material combinations and microstructure design, so that cables can achieve outstanding ozone resistance and abrasion resistance while maintaining an excellent balance of overall performance, is a technological bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0006] One of the objectives of this invention is to provide an ozone-resistant and abrasion-resistant rubber-sheathed cable to solve the technical problem that it is difficult to simultaneously achieve ozone resistance and abrasion resistance in existing rubber-sheathed cables.

[0007] The objective of this invention can be achieved through the following technical solutions: An ozone-resistant and abrasion-resistant rubber-sheathed cable, its structure comprising, from the inside out, a conductor, an insulation layer, and an outer sheath, wherein the outer sheath material, by weight, comprises the following raw materials: 80-100 parts of chlorinated polyethylene matrix; 12-20 parts of the polymer composition; 15-35 parts of functionalized halloysite nanotube composite; 20-40 parts of reinforcing agent; Plasticizer 10-20 parts; Anti-aging agent 2-4 parts; 5-7 parts of cross-linking promoting system; 2-4 parts lubricant; Chlorinated polyethylene matrix is ​​a chlorinated polymer with a saturated main chain, serving as the base material for the entire composite system; its C-C and some C-Cl main chains contain little or no unsaturated double bonds that are easily attacked by ozone, providing basic ozone resistance from the root of molecular structure. The polymer composition is a combination of hydrogenated styrene-isoprene block copolymer (SEPS) and acrylonitrile-butadiene copolymer (NBR) in a mass ratio of (7~9):(2~4). As a macromolecular compatibilizer and performance modifier, the saturated SEPS backbone provides excellent ozone resistance, thermo-oxidative resistance and dynamic flexural properties, while the polar NBR segments are well compatible with the chlorinated polyethylene matrix and synergistically improve oil resistance. The functionalized halloysite nanotube composite is obtained by synergistic surface modification of halloysite nanotubes with sulfur-containing silane coupling agents and benzotriazole ultraviolet absorbers.

[0008] Ordinary halloysite nanotubes, due to their numerous surface hydroxyl groups and strong hydrophilicity, tend to agglomerate severely in organic rubber and lack interfacial bonding. This invention employs a pre-designed modification process to graft sulfur-containing silanes onto the outer wall and load ultraviolet absorbers onto the inner cavity. The Si-69 / Si-75 grafted onto the outer wall contains polysulfide or disulfide bonds. Under peroxide initiation, these sulfur bonds can homolytically cleave and combine with CPE / NBR macromolecular free radicals, thereby chemically "anchoring" the rigid nanotubes to the rubber crosslinking network through strong covalent bonds. This "anchoring" achieves efficient stress transfer from the flexible matrix to the rigid reinforcement, significantly improving wear resistance and modulus, and preventing nanofiller migration. The inner cavity loading utilizes the inherent hollow structure of the halloysite nanotubes, "injecting" the small organic molecule absorber through the capillary effect under vacuum negative pressure, forming a "nano-slow-release capsule." During use, the substance inside the cavity is slowly released, continuously replenishing the antioxidant consumed in the matrix, achieving long-lasting dynamic protection. This is a functional utilization of the unique geometric structure of nanomaterials.

[0009] Reinforcing agents, plasticizers, antioxidants, crosslinking promoters, and lubricants: these are essential functional additives in practical rubber formulations, each playing a fundamental role in reinforcing, plasticizing, providing immediate anti-aging, establishing stable crosslinking networks, and improving processing performance. Among them, the DCP-TAIC peroxide system establishes high-energy CC crosslinks, which are inherently more heat- and ozone-resistant than the polysulfide bonds crosslinked by sulfur.

[0010] Furthermore, the sulfur-containing silane coupling agent is bis-(3-triethoxysilylpropyl)-tetrasulfide (Si-69) or bis-(3-triethoxysilylpropyl)-disulfide (Si-75). The benzotriazole ultraviolet absorber is 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole (UV-326) or 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (UV-P).

[0011] Si-69 and Si-75 are mature sulfur-containing silanes used in the rubber industry, and their ability to crosslink with rubber has been extensively verified. UV-326 and UV-P are highly efficient benzotriazole ultraviolet absorbers that can dissipate ultraviolet light energy as heat through intramolecular proton transfer, thus protecting the polymer chains.

[0012] Furthermore, the preparation method of the functionalized halloysite nanotube composite includes the following steps: S1: Dissolve benzotriazole UV absorbers in anhydrous ethanol, add halloysite nanotubes, and ultrasonically disperse them evenly. Stir under vacuum to allow absorber molecules to enter the halloysite nanotube lumen. Then filter and dry at low temperature to obtain pre-loaded halloysite nanotubes. Use vacuum negative pressure to remove air from the lumen, allowing the absorber solution to enter the nanotube lumen under capillary force. Then filter and dry at low temperature to obtain pre-loaded halloysite nanotubes with UV absorbers pre-loaded in the lumen.

[0013] S2: The pre-loaded halloysite nanotubes obtained in step S1 are dispersed in an ethanol-water mixed solution. A sulfur-containing silane coupling agent is added, and the pH is adjusted to 4-5. The mixture is subjected to a hydrolysis-condensation reaction at 50-70°C for 2-4 hours. During this reaction, the silanol groups of the silane coupling agent undergo a condensation reaction with the hydroxyl groups on the outer wall of the halloysite, forming Si-O-Al / Si covalent bonds, which are then grafted onto the outer wall of the tube. The mixture is then filtered, washed, and dried to obtain the functionalized halloysite nanotube composite.

[0014] Furthermore, in step S1, the mass ratio of halloysite nanotubes to benzotriazole ultraviolet absorbers is 100:(2~5); in step S2, the mass ratio of pre-loaded halloysite nanotubes to sulfur-containing silane coupling agents is 100:(3~8).

[0015] Furthermore, the halloysite nanotubes have a length of 0.5~1.5μm, an outer diameter of 50~80nm, and an inner diameter of 15~30nm.

[0016] Furthermore, the mass ratio of the functionalized halloysite nanotube composite, the polymer composition, and the chlorinated polyethylene matrix is ​​(2~3.5):(1.2~1.6):(8.5~9.5). This ratio range ensures that the phase structure and synergistic network among the nanofiller, polymer modifier, and matrix achieve optimal balance.

[0017] Furthermore, the reinforcing agent is a composition of fast-extrusion carbon black N550, semi-reinforcing carbon black N774, and silica, with a mass ratio of (2~3):(1~2):1. By using carbon black with different particle sizes and structures to compound silica, it is possible to meet the wear resistance requirements while also taking into account the processing and extrusion performance and surface smoothness of the rubber compound.

[0018] Furthermore, the plasticizer is at least one of trioctyl trimellitate, dioctyl terephthalate, or dioctyl sebacate. These high-temperature resistant, low-volatility plasticizers help to reduce the negative impact of plasticizer migration on aging resistance while ensuring flexibility.

[0019] Furthermore, the crosslinking-promoting system is a composition of dicumyl peroxide and the accelerator triallyl isocyanurate, with a mass ratio of (2~3):(1~1.4). This peroxide-co-crosslinking agent system can efficiently establish carbon-carbon crosslinking bonds in polar rubbers such as chlorinated polyethylene and NBR, with high crosslinking bond energy and stable structure, far superior to the heat, oxygen, and ozone resistance of the sulfur vulcanization system.

[0020] Furthermore, the conductor is a multi-stranded oxygen-free copper wire; the insulating layer material is ethylene-vinyl acetate copolymer or ethylene propylene diene monomer (EPDM) rubber.

[0021] Furthermore, the insulating layer material also contains 8 to 15 parts by weight of a polymeric composition. More preferably, the insulating layer material also contains a polymeric composition to enhance interlayer compatibility and flexural strength.

[0022] Furthermore, the preparation method of ozone-resistant and highly abrasion-resistant rubber-sheathed cable includes the following steps: Step 1: Preparation of functionalized halloysite nanotube composites; Step 2: Mix the chlorinated polyethylene matrix, polymer composition, functionalized halloysite nanotube composite, reinforcing agent, plasticizer, antioxidant, crosslinking promotion system and lubricant in an internal mixer according to the formula, and mix at 90~110℃ for 6~10 minutes to obtain the compound. Step 3: The compounded rubber is extruded onto the wire core consisting of a conductor and an insulation layer, and then continuously vulcanized for 5 to 10 minutes under steam conditions of 160~180℃ and 1.0~1.3MPa. After cooling and winding, the ozone-resistant and abrasion-resistant rubber-sheathed cable is obtained.

[0023] The beneficial effects of this invention are: (1) This invention solves the technical problem of the difficulty in simultaneously achieving ozone aging resistance and wear resistance in rubber-sheathed cables by introducing halloysite nanotube composites that have undergone dual-functional synergistic modification through "covalent grafting of the outer wall and physical loading of the inner cavity". However, when halloysite nanotubes are used directly, their outer wall silanol groups result in strong hydrophilicity, making them prone to aggregation in weakly polar matrices. Furthermore, the smooth tubular surface has only weak van der Waals forces with the matrix, resulting in insufficient interfacial bonding and easy slippage under stress, becoming stress defect points. At the same time, the traditional method of directly adding antioxidants has the defects of rapid migration and volatilization, and continuous decay of long-term protective efficacy. This invention implements synergistic modification from two dimensions. In terms of the physical loading of the inner cavity, benzotriazole ultraviolet absorbers are loaded into the nanotube cavity using the vacuum negative pressure-assisted capillary effect, transforming them into microscopic slow-release carriers. Based on the concentration gradient, they are continuously released during service to replenish the consumed antioxidants, constructing a long-term dynamic chemical protection mechanism and overcoming the defect of the traditional antioxidant efficacy decaying over time. In the dimension of covalent grafting on the outer wall, sulfur-containing silane coupling agents are covalently grafted onto the outer wall surface through hydrolysis and condensation reaction. Their polysulfide bonds participate in the rubber crosslinking reaction during the peroxide crosslinking process, anchoring the nanotubes in the crosslinking network through covalent chemical bonds, effectively transferring and dispersing the load. When microcracks extend to the anchored nanotubes, the rigid tubular structure forces the crack tip to deflect and pin, significantly consuming fracture energy and endowing the material with wear resistance far exceeding that of traditional spherical fillers.

[0024] (2) The functional halloysite nanotube composite used in this invention produces a deep synergistic effect in the dimensions of physical load in the inner cavity and covalent grafting on the outer wall: the covalent bonding on the outer wall ensures that the nanotubes are firmly fixed in the network to exert mechanical performance, forming a structural premise for wear resistance and reinforcement; the slow release in the inner cavity superimposes long-term chemical protection on the basis of mechanical protection, and because the slow release source is anchored to the cross-linked network, the release area is precisely distributed in the micro-regions with severe stress deformation, and the protection efficiency is significantly improved; the organic segments grafted on the outer wall improve the surface polarity of the nanotubes and enhance dispersibility, providing a premise for the performance of nano-functions.

[0025] (3) The 15-35 parts of functionalized halloysite nanotube composite used in this invention form a system-level synergy with other necessary components in the system: 80-100 parts of chlorinated polyethylene matrix provide an ozone-resistant chemical inert basis with a saturated main chain; in the 12-20 parts of polymer composition, hydrogenated styrene-isoprene block copolymer provides dynamic flexibility and additional ozone resistance, while acrylonitrile-butadiene copolymer enhances oil resistance and improves the interfacial compatibility between the matrix and nanotubes; 20-40 parts of reinforcing agent constructs a traditional filler network at the micron scale, forming a multi-level reinforced anti-wear system with the nanotube skeleton; 10-20 parts of plasticizer imparts good processing fluidity to the compound and adjusts the hardness and flexibility of the final product. 2-4 parts of antioxidant serve as a supplement to the initial protection and slow-release system, providing immediate protection in the early stages of material use. 5-7 parts of crosslinking system construct a high-bond-energy carbon-carbon crosslinking network, ensuring that each mechanism functions stably under long-term thermo-oxidative conditions. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0027] The main sources of the raw materials used in the following examples and comparative examples are as follows: Chlorinated polyethylene (CPE), model 135B; Hydrogenated styrene-isoprene block copolymer (SEPS); Acrylonitrile-butadiene copolymer (NBR); Halloysite nanotubes (HNTs) have a length of 0.8–1.2 μm, an outer diameter of 60–80 nm, and an inner diameter of 20–25 nm. bis-(3-triethoxysilylpropyl)-tetrasulfide (Si-69); bis-(3-triethoxysilylpropyl)-disulfide (Si-75); UV absorber UV-326; Carbon black N550, carbon black N774; Silica, fumed silica, specific surface area 200 m² / g; Trioctyl trimellitate (TOTM); Dioctyl sebacate (DOS); Dicumyl peroxide (DCP); Triallyl isocyanurate (TAIC); All other unmentioned additives are commercially available industrial products.

[0028] Preparation Example 1: Preparation of Functionalized Halloysite Nanotube Composites (F-HNTs-1) S1: Dissolve 3g of UV absorber UV-326 in 200ml of anhydrous ethanol, add 100g of halloysite nanotubes, and ultrasonically disperse for 30 minutes to form a suspension. Place the suspension in a sealed container connected to a vacuum pump and stir for 2 hours under a vacuum of -0.09MPa. After releasing the vacuum, allow it to stand, filter, wash with a small amount of cold ethanol, and vacuum dry at 30℃ to obtain pre-loaded halloysite nanotubes with UV-326 pre-loaded in the inner cavity.

[0029] S2: Disperse 100g of the pre-loaded halloysite nanotubes in a mixed solvent of 500ml ethanol and 150ml deionized water, add 6g of silane coupling agent Si-69, adjust the pH to 4.5 with glacial acetic acid, heat to 60℃, and stir at a constant temperature for 3.5 hours for hydrolysis and condensation reaction. After the reaction is complete, cool to room temperature, filter, wash repeatedly with ethanol and deionized water, dry under vacuum at 80℃ to constant weight, and grind through a 300-mesh sieve to obtain the functionalized halloysite nanotube composite, denoted as F-HNTs-1.

[0030] Preparation Example 2: Preparation of Functionalized Halloysite Nanotube Composites (F-HNTs-2) The only difference between this preparation example and Preparation Example 1 is that in step S2, the silane coupling agent used is Si-75, and the amount added is 4g. The resulting product is denoted as F-HNTs-2.

[0031] Preparation Example 3: Preparation of Functionalized Halloysite Nanotube Composites (F-HNTs-3) The only difference between this preparation example and Preparation Example 1 is that in step S1, the amount of ultraviolet absorber UV-326 is 2g; and in step S2, the amount of silane coupling agent Si-69 added is 8g. The resulting product is designated as F-HNTs-3.

[0032] Preparation Example 4: Preparation of Functionalized Halloysite Nanotube Composites (F-HNTs-4) The only difference between this preparation example and Preparation Example 1 is that in step S1, the amount of ultraviolet absorber UV-326 is 5g; and in step S2, the amount of silane coupling agent Si-69 added is 3g. The resulting product is designated as F-HNTs-4.

[0033] Comparative Preparation Example 1: Halloysite nanotubes (Si-HNTs) with silane grafted only on the outer wall 100g of halloysite nanotubes were directly dispersed in an ethanol-water mixed solvent, and 6g of silane coupling agent Si-69 was added. The subsequent processing steps were the same as those for S2 in Preparation Example 1. The resulting product was denoted as Si-HNTs.

[0034] Comparative Preparation Example 2: Halloysite nanotubes (UV-HNTs) with UV absorbers loaded only in the inner cavity The preparation steps are the same as S1 in Preparation Example 1, but step S2 only involves washing and drying, without silane coupling agent treatment. The resulting product is denoted as UV-HNTs.

[0035] Comparative Preparation Example 3: Unmodified Halloysite Nanotubes (HNTs) That is, the halloysite nanotubes purchased in their original form are used directly without any treatment.

[0036] Example 1 An ozone-resistant and abrasion-resistant rubber-sheathed cable has a structure consisting of a conductor, an insulation layer, and an outer sheath, from the inside out.

[0037] The conductor is a bundle of oxygen-free copper wires with a single wire diameter of 0.15 mm, twisted together, with a cross-sectional area of ​​10 mm².

[0038] Insulation layer material formulation (parts by weight): 100 parts EVA (VA content 33%), 10 parts polymer composition (SEPS:NBR=8:2.5), 30 parts flame retardant (aluminum hydroxide), 15 parts reinforcing filler (fumed silica), 1 part antioxidant RD, 3 parts crosslinking agent DCP, 1.5 parts co-crosslinking agent TAIC, and 4 parts processing aids. The mixture is compounded, extruded, and vulcanized to form an insulation layer approximately 0.7 mm thick, which is then coated onto the conductor.

[0039] Outer sheath material formulation (parts by weight): CPE 92 parts, polymer composition (SEPS:NBR=8.5:3) 15 parts, functionalized halloysite nanotube composite F-HNTs-125 parts, reinforcing agent (carbon black N550:carbon black N774:white carbon black=3:1.5:1) 32 parts, plasticizer TOTM 15 parts, antioxidant RD 1.5 parts, antioxidant 445 1.5 parts, crosslinking promotion system (DCP:TAIC=3:1.2) 6.5 parts, lubricant (polyethylene wax) 3.5 parts.

[0040] Outer sheath preparation method: Mix all the above raw materials in a Banbury mixer at 100℃ for 8 minutes, and discharge the rubber. Use a rubber extruder to extrude the mixed rubber onto the prepared insulated wire core, and then put it into a pressurized steam vulcanizing tube for vulcanization at 175℃ and 1.2MPa for 8 minutes. After cooling and winding, the finished rubber-sheathed cable is obtained. The outer sheath thickness is 1.6mm.

[0041] Example 2 The only difference between this embodiment and Example 1 is that the proportion of functionalized halloysite nanotube composite F-HNTs-1 in the outer sheath material formulation is adjusted to 20 parts, and the proportion of reinforcing agent is adjusted to 28 parts. All other aspects are the same.

[0042] Example 3 The only difference between this embodiment and Embodiment 1 is that F-HNTs-2 of equal quality is used to replace F-HNTs-1 in the outer sheath material formulation. Everything else is the same.

[0043] Example 4 The only difference between this embodiment and Example 1 is that in the outer sheath material formulation, the amount of the polymer composition is adjusted to 12 parts, the amount of CPE is adjusted to 88 parts, and the amount of functionalized halloysite nanotube composite F-HNTs-1 is adjusted to 30 parts. All other aspects are the same.

[0044] Example 5 The only difference between this embodiment and Embodiment 1 is that F-HNTs-3 of equal quality is used instead of F-HNTs-1 in the outer sheath material formulation. Everything else is the same.

[0045] Example 6 The only difference between this embodiment and Example 1 is that: in the outer sheath material formulation, F-HNTs-4 is used in place of F-HNTs-1 by mass; DOS is used in place of TOTM as the plasticizer; and the mass ratio of SEPS to NBR in the polymer composition is adjusted to 7:4. Everything else is the same.

[0046] Example 7 The only difference between this embodiment and Embodiment 1 is that the mass ratio of reinforcing agent (carbon black N550: carbon black N774: silica) in the outer sheath material formulation is adjusted to 2:2:1. Everything else is the same.

[0047] Example 8 The only difference between this embodiment and Example 1 is that the amount of the polymeric composition (SEPS:NBR=8:2.5) used in the insulating layer material is 14 parts. All other aspects are the same.

[0048] Comparative Example 1 The only difference between this comparative example and Example 1 is that the outer sheath formulation contains no functionalized halloysite nanotube composite, and the amount of reinforcing agent (carbon black N550: carbon black N774: silica = 3:1.5:1) is increased to 55 parts to attempt to achieve similar original mechanical strength. All other aspects are the same.

[0049] Comparative Example 2 The only difference between this comparative example and Example 1 is that 25 parts of the functionalized halloysite nanotube composite F-HNTs-1 were replaced with an equal amount of the unmodified original halloysite nanotubes (HNTs) obtained in Comparative Preparation Example 3. All else is the same.

[0050] Comparative Example 3 The only difference between this comparative example and Example 1 is that the functionalized halloysite nanotube composite F-HNTs-1 is replaced with an equal amount of the product obtained in Comparative Preparation Example 2, which is only loaded in the cavity and has no outer wall grafting (UV-HNTs). Everything else is the same.

[0051] Comparative Example 4 The only difference between this comparative example and Example 1 is that the functionalized halloysite nanotube composite F-HNTs-1 is replaced with an equal amount of the product (Si-HNTs) obtained in Comparative Preparation Example 1, which is only grafted on the outer wall and has no internal cavity loading. Everything else is the same.

[0052] Comparative Example 5 The only difference between this comparative example and Example 1 is that the amount of functionalized halloysite nanotube composite F-HNTs-1 in the outer sheath formulation is 45 parts, and the amount of the polymer composition is reduced to 8 parts. All other aspects are the same.

[0053] Comparative Example 6 The only difference between this comparative example and Example 1 is that the outer sheath formulation contains no polymeric composition (SEPS and NBR), and its 15 parts are entirely replaced with CPE. All other aspects are the same.

[0054] Performance testing The outer sheath materials of the rubber-sheathed cables prepared in all the above embodiments and comparative examples were subjected to the following performance tests according to standard methods. The results are shown in Table 1.

[0055] 1. Conventional mechanical properties: According to GB / T 528-2009, tensile strength (MPa) and elongation at break (%) were tested at a tensile speed of 250 mm / min.

[0056] 2. Hot air aging performance: According to GB / T 3512-2014, the tensile strength and elongation at break were aged in an oven at 100℃ for 72 hours, and the change rate (%) of tensile strength and elongation at break was tested and the absolute value was taken.

[0057] 3. Ozone aging resistance: According to GB / T 7762-2014, under the conditions of ozone concentration of 100pphm, temperature of 40℃, and static tensile stress of 20%, the sample was aged for 72 hours, and the surface of the sample was observed with a 10x magnifying glass to see if cracks appeared.

[0058] 4. Abrasion resistance: Tested according to GB / T 1689-2014 using an Akron abrasion tester. The results are based on the abrasion volume (cm³) over a distance of 1.61 km. 3 The smaller the value, the better the wear resistance.

[0059] 5. Dynamic flexural performance: Conduct 3000 bidirectional 90-degree bending tests on cable samples with sheaths and observe whether there are cracks on the sheath surface.

[0060] The results are shown in Table 1: Table 1

[0061] As shown in Table 1, Comparative Example 1, which does not contain functionalized halloysite nanotube composites, exhibits a wear rate as high as 0.155 cm² even with only an increase in the amount of traditional reinforcing agent. 3 At a distance of 1.61 km, ozone aging resulted in slight cracks, and the change in elongation at break after thermal aging reached -12.8%. In Example 1, the wear amount was only 0.065 cm. 3 / 1.61km, a reduction of approximately 58%, with no cracks observed during ozone aging. This is because traditional spherical fillers cannot achieve crack deflection and pinning effects, and lack sustained-release protection. In contrast, the functionalized halloysite nanotubes of this invention achieve effects that traditional systems cannot reach at both the wear mechanism and long-term protection levels through the synergistic effect of chemical anchoring and sustained-release within the lumen.

[0062] Comparing Example 1 with Comparative Examples 2, 3, and 4, Comparative Example 2 used unmodified halloysite nanotubes, which, due to aggregation and interfacial defects, had a tensile strength of only 12.8 MPa and a wear rate of 0.180 cm. 3 At a distance of 1.61 km, the ozone layer showed significant cracking, with performance even inferior to traditional systems. Comparative Example 3, with only internal cavity loading and no external wall grafting, exhibited a wear rate of 0.162 cm. 3 / 1.61km, with no substantial improvement in wear resistance, indicating that the mechanical reinforcement function of nanotubes cannot be utilized without chemical anchoring. Comparative Example 4 only underwent outer wall grafting without internal cavity loading, although the wear rate improved to 0.095cm. 3 / 1.61km, but the performance retention rate after thermal aging is significantly worse than that of Example 1, indicating that the long-term protection capability is insufficient when there is no sustained-release mechanism.

[0063] Comparing Example 1 and Comparative Example 5, Comparative Example 5 increased the functionalized halloysite nanotube composite to 45 parts while reducing the polymer composition to 8 parts, resulting in a wear rate as low as 0.051 cm. 3 The cable's elongation at break was 1.61 km, but it dropped sharply to 310%, and edge cracking occurred during the bending test. This indicates that when the amount of nanotubes exceeds the optimal range and the flexible component is insufficient, the material becomes too rigid and loses the flexibility required for rubber-sheathed cables.

[0064] Compared with Comparative Example 6, Example 1 contained no polymeric composition, resulting in a tensile strength of only 13.8 MPa, an elongation at break of only 390%, and an abrasion loss of 0.148 cm. 3 At 1.61 km, slight cracks appeared in the ozone layer. SEPS in the polymer composition provides flexibility and additional ozone resistance, while NBR improves interfacial compatibility. Without these components, nanotube dispersion and interfacial bonding deteriorate, resulting in a comprehensive decline in overall performance, demonstrating the indispensability of the polymer composition in the system.

[0065] Within the scope defined by this invention, Examples 1-8 exhibit tensile strengths of 15.8-17.0 MPa, elongation at break of 430%-480%, and abrasion loss of 0.058-0.072 cm. 3 / 1.61km, no cracks were found during ozone aging, and no cracks were found during bending tests, indicating that the technical solution of the present invention can stably achieve excellent comprehensive performance over a wide range and has good reliability and reproducibility.

[0066] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. An ozone-resistant and highly abrasion-resistant rubber-sheathed cable, comprising, from the inside out, a conductor, an insulation layer, and an outer sheath, characterized in that, The outer sheath material, by weight, comprises the following raw materials: 80-100 parts of chlorinated polyethylene matrix; 12-20 parts of the polymer composition; 15-35 parts of functionalized halloysite nanotube composite; 20-40 parts of reinforcing agent; Plasticizer 10-20 parts; Anti-aging agent 2-4 parts; 5-7 parts of cross-linking promoting system; 2-4 parts lubricant; The polymer composition is a combination of hydrogenated styrene-isoprene block copolymer and acrylonitrile-butadiene copolymer, with a mass ratio of (7~9):(2~4). The functionalized halloysite nanotube composite is obtained by synergistic surface modification of halloysite nanotubes with sulfur-containing silane coupling agents and benzotriazole ultraviolet absorbers.

2. The ozone-resistant and abrasion-resistant rubber-sheathed cable according to claim 1, characterized in that, The sulfur-containing silane coupling agent is bis-(3-triethoxysilylpropyl)-tetrasulfide or bis-(3-triethoxysilylpropyl)-disulfide; The benzotriazole ultraviolet absorber is 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole or 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

3. The ozone-resistant and abrasion-resistant rubber-sheathed cable according to claim 1, characterized in that, The functionalized halloysite nanotube composite is prepared by the following steps: S1: Dissolve benzotriazole UV absorbers in anhydrous ethanol, add halloysite nanotubes, and after ultrasonic dispersion, stir under vacuum to allow absorber molecules to enter the halloysite nanotube lumen. Then filter and dry at low temperature to obtain preloaded halloysite nanotubes. S2: Disperse the preloaded halloysite nanotubes obtained in step S1 in an ethanol-water mixed solution, add a sulfur-containing silane coupling agent, adjust the pH to 4-5, and perform a hydrolysis-condensation reaction at 50-70°C for 2-4 hours. Then filter, wash, and dry to obtain the functionalized halloysite nanotube composite.

4. The ozone-resistant and abrasion-resistant rubber-sheathed cable according to claim 3, characterized in that, In step S1, the mass ratio of halloysite nanotubes to benzotriazole UV absorbers is 100:(2~5); in step S2, the mass ratio of pre-loaded halloysite nanotubes to sulfur-containing silane coupling agents is 100:(3~8).

5. The ozone-resistant and abrasion-resistant rubber-sheathed cable according to claim 1, characterized in that, The halloysite nanotubes have a length of 0.5~1.5μm, an outer diameter of 50~80nm, and an inner diameter of 15~30nm.

6. The ozone-resistant and abrasion-resistant rubber-sheathed cable according to claim 1, characterized in that, The mass ratio of the functionalized halloysite nanotube composite, the polymer composition, and the chlorinated polyethylene matrix is ​​(2~3.5):(1.2~1.6):(8.5~9.5).

7. The ozone-resistant and abrasion-resistant rubber-sheathed cable according to claim 1, characterized in that, The reinforcing agent is a composition of fast-extrusion carbon black N550, semi-reinforcing carbon black N774 and silica, with a mass ratio of (2~3):(1~2):1; The plasticizer is at least one of trioctyl trimellitate, dioctyl terephthalate, or dioctyl sebacate. The cross-linking system is a composition of dicumyl peroxide and accelerator triallyl isocyanurate, with a mass ratio of (2~3):(1~1.4).

8. The ozone-resistant and abrasion-resistant rubber-sheathed cable according to claim 1, characterized in that, The conductor is a multi-stranded oxygen-free copper wire; the insulating layer material is ethylene-vinyl acetate copolymer or ethylene propylene diene monomer (EPDM) rubber.

9. The ozone-resistant and abrasion-resistant rubber-sheathed cable according to claim 1, characterized in that, The insulating layer material further comprises 8 to 15 parts by weight of a polymeric composition.

10. The ozone-resistant and abrasion-resistant rubber-sheathed cable according to claim 1, characterized in that, Its preparation method includes the following steps: Step 1: Preparation of functionalized halloysite nanotube composites; Step 2: Mix the chlorinated polyethylene matrix, polymer composition, functionalized halloysite nanotube composite, reinforcing agent, plasticizer, antioxidant, crosslinking promotion system and lubricant in an internal mixer according to the formula, and mix at 90~110℃ for 6~10 minutes to obtain the compound. Step 3: The compounded rubber is extruded onto the wire core consisting of a conductor and an insulation layer, and then continuously vulcanized for 5 to 10 minutes under steam conditions of 160~180℃ and 1.0~1.3MPa. After cooling and winding, the ozone-resistant and abrasion-resistant rubber-sheathed cable is obtained.

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