A rat-proofing and termite-proofing cable sheath material with a repairing function and a preparation method thereof

Abstract

The application discloses a rat and termite prevention cable sheath material with a repairing function and a preparation method thereof, and relates to the technical field of high polymer materials for wires and cables.The application is characterized in that pH-sensitive tannic acid capsules and starch enzyme-specific degradation cross-linking accelerator capsules are cooperatively designed, so that the repairing system triggers the release of the core material and the complete repairing reaction simultaneously only in the specific scenario of rat and termite biting and saliva release, completely avoids the false triggering of non-target scenarios such as soil pH fluctuation and conventional mechanical scratches, and solves the core defects of the early loss of the core material of the traditional self-repairing system and the premature failure of the function. 3+ The application adopts a hierarchical progressive repairing path, realizes instant physical plugging of the damaged area through the rapid action of tannic acid and saliva mucin first, and then completes the transition from temporary plugging to permanent structure repairing through the multiple coordination cross-linking of Fe 3+ ions to build a dense three-dimensional network structure, and the mechanical property retention rate of the repairing area is excellent.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology for wires and cables, specifically to a rodent- and ant-proof cable sheath material with repair function and its preparation method. Background Technology

[0002] With the rapid development of power and communication infrastructure in my country, cable laying scenarios are increasingly extending to complex environments such as the wild, underground pipe corridors, and mountainous areas. Damage to the cable sheath caused by rodent and ant bites is a core cause of cable insulation failure, line interruptions, and even safety accidents. This type of damage is highly concealed and has high inspection and maintenance costs. Existing technologies are unable to simultaneously meet the core needs of long-term rodent and ant protection and self-repair of damage.

[0003] Currently, the mainstream rodent and ant protection sheathing technologies in the industry are divided into two categories: chemical repellency and physical protection. Chemical repellency has problems such as easy migration and precipitation of functional components, continuous decline in protective effectiveness over service time, and significant environmental risks. It also cannot repair existing bite damage. Physical protection, on the other hand, has drawbacks such as high production costs, difficult installation, and poor processing adaptability. It also lacks the ability to repair damage. Once the sheath is damaged, it will lose its protective ability, leading to the intrusion of corrosive media and the overall failure of the cable.

[0004] Existing self-healing technologies for cables are mostly microcapsule systems or intrinsic dynamic bond systems with single physical triggering. Intrinsic systems require external triggering conditions such as high temperature and light, which are not suitable for underground direct burial scenarios without external triggering. Conventional microcapsule systems rely solely on mechanical damage for triggering, lacking specificity of damage source and unable to distinguish between rodent and ant bites and routine construction scratches or environmental stress cracking. They are prone to false triggering and premature loss of core material in complex soil environments, and have low retention of mechanical properties after repair. They cannot resist corrosion from damp underground environments and secondary rodent and ant bites, making it difficult to meet the requirements for long-term stable service of cables.

[0005] In summary, developing rodent-proof and self-healing protective sheath materials that exhibit strong trigger specificity, targeted response to rodent and ant biting behavior, excellent resistance to environmental interference, outstanding repair performance, and compatibility with existing industrial production lines is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the aforementioned shortcomings of existing technologies, this invention provides a rodent- and ant-proof cable sheath material with repair function and its preparation method, which can specifically identify rodent and ant saliva and actively trigger a self-repair function.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A rodent- and ant-proof cable sheath material with repair function is provided, which includes a structural layer and a repair layer from the inside to the outside; the structural layer is made of high-density polyethylene material. The repair layer uses high-density polyethylene as a matrix, in which two-component microcapsules are uniformly dispersed; the two-component microcapsules include tannic acid capsules and cross-linking accelerator capsules; The core material of the tannic acid capsule is tannic acid or its derivative, and the wall material is a pH-responsive polymer. The wall material of the tannic acid capsule dissolves or swells in a slightly acidic to neutral environment with a pH value > 5.5. The core material of the cross-linking accelerator capsule is a metal ion cross-linking agent, and the wall material is an enzyme-responsive polymer. The wall material of the cross-linking accelerator capsule can be specifically degraded by amylase in saliva.

[0008] Furthermore, the pH-responsive polymer is a methacrylic acid-ethyl acrylate copolymer obtained by copolymerizing methacrylic acid and ethyl acrylate in a mass ratio of 1:1.

[0009] Furthermore, the metal ion crosslinking agent is ferric citrate, and the enzyme-responsive polymer is a chitosan-sodium alginate complex.

[0010] Furthermore, tannic acid capsules are prepared using the following steps: A1: Weigh out the methacrylate-ethyl acrylate copolymer powder and slowly add it to an anhydrous ethanol / water mixed solvent with a volume ratio of 7:3. Stir at 300 r / min in a constant temperature water bath at 40℃ until the polymer is completely dissolved to obtain a clear and transparent wall material solution. A2: Weigh out tannic acid and add it to the wall material solution. At the same time, add emulsifier and emulsify for 5-8 minutes using a high-speed shear emulsifier at a speed of 8000r / min to form a stable oil-in-water emulsion. A3: The water-in-oil emulsion is spray-dried at an inlet air temperature of 150~160℃, an outlet air temperature of 75~85℃, a peristaltic pump speed of 15~20r / min, and a spray pressure of 0.2~0.25MPa to obtain microcapsule powder. The microcapsule powder is then dried in a vacuum drying oven at 40℃ for 4 hours to obtain tannic acid capsules.

[0011] Furthermore, the emulsifier is Tween-80; the ratio of methacrylate-ethyl acrylate copolymer powder, anhydrous ethanol / water mixed solvent, tannic acid and emulsifier is 20g:380g:8g:0.5g.

[0012] Furthermore, the cross-linking accelerator capsules are prepared using the following steps: B1: Weigh out chitosan and dissolve it in 1% glacial acetic acid solution to prepare a chitosan-acetic acid solution with a chitosan concentration of 2%; weigh out sodium alginate and dissolve it in deionized water to prepare a sodium alginate aqueous solution of 2%; mix equal volumes of chitosan-acetic acid solution and sodium alginate aqueous solution and stir evenly at 40℃ to obtain chitosan-sodium alginate composite wall material solution. B2: Take ferric citrate and disperse it evenly into the chitosan-sodium alginate composite wall material solution to obtain a core material-wall material mixture; B3: Dissolve anhydrous calcium chloride in deionized water to prepare a 0.5% calcium chloride aqueous solution; drip the core material-wall material mixture into the calcium chloride aqueous solution under continuous stirring at 200 r / min through a fine needle with a diameter of 0.4~0.6 mm at a constant speed, and the dripping height is 10~15 cm; when the core material-wall material mixture comes into contact with calcium ions, a cross-linking reaction occurs immediately, and it solidifies into spherical microcapsules; B4: After the addition is complete, let it stand for 30-60 minutes to solidify, then filter and wash with deionized water. Then freeze-dry at -50℃ for 24-48 hours until constant weight is obtained to obtain dried crosslinking accelerator capsules.

[0013] Furthermore, the ratio of chitosan-sodium alginate composite wall material solution to ferric citrate is 190g:10g.

[0014] The present invention also provides a method for preparing the above-mentioned rodent- and ant-proof cable sheath material with repair function, comprising the following steps: S1: Dry 100 parts of high-density polyethylene at 80°C for 2 hours, and mix the dried high-density polyethylene with 5-10 parts of tannic acid capsules, 3-10 parts of crosslinking accelerator capsules, 1-3 parts of dispersant and 0.5-1 parts of antioxidant at 500r / min for 10 minutes at room temperature. S2: The mixed materials are added to a co-rotating parallel twin-screw extruder for melt blending. The extruded strips are cooled in a water tank, air-dried, and then granulated to obtain functionalized HDPE sheath material. S3: After drying the functionalized HDPE sheath material at 80℃ for 4 hours, use a co-extrusion process to feed the high-density polyethylene and functionalized HDPE sheath material into a single screw extruder and extrude them onto the surface of the core material to be coated.

[0015] Furthermore, in step S2, the process parameters for melt blending are set as follows: zone 1 temperature 150℃, zone 2 temperature 160℃, zone 3 temperature 170℃, zone 4 temperature 170℃, die head temperature 165℃, and screw speed 150r / min.

[0016] Furthermore, in step S3, the extrusion temperature is set as follows: 150°C for the feeding section, 165°C for the compression section, 170°C for the metering section, 170°C for the die head, and the screw speed is controlled at 20~30 r / min.

[0017] The beneficial effects of this invention are as follows: This invention addresses the industry pain points of existing rodent- and ant-resistant cable sheathing materials, which fail to target rodent and ant biting behavior effectively, have insufficient trigger specificity in their self-healing systems, are prone to non-targeted false triggering, and whose repair effects are difficult to adapt to the long-term service requirements of underground cables. It constructs a self-healing protection system that is dually triggered by both physical damage from rodent and ant biting and saliva biomarkers, achieving accurate identification and efficient repair of rodent and ant biting damage. Through the synergistic design of pH-sensitive tannic acid capsules and amylase-specifically degraded cross-linking accelerator capsules, the repair system is designed to trigger the core material release and complete repair reaction only in specific scenarios where rodents and ants bite and release saliva. This completely avoids false triggering by non-target scenarios such as soil pH fluctuations and conventional mechanical scratches, solving the core defects of traditional self-healing systems, such as premature core material loss and premature functional failure.

[0018] This invention employs a graded, progressive repair pathway. First, it achieves immediate physical sealing of the damaged area through the rapid interaction of tannic acid and salivary mucin. Then, it utilizes Fe... 3+ The multiple coordination crosslinking of ions constructs a dense three-dimensional network structure, completing the transformation from temporary sealing to permanent structural repair. The mechanical properties of the repaired area are well maintained, and it has good resistance to water permeability and secondary biting, which can effectively block the intrusion of corrosive media.

[0019] The formula and preparation process of this invention are fully compatible with the existing mainstream production lines for HDPE cable sheaths. No new special equipment is required. The process is simple and controllable, easy to promote industrially, and can greatly improve the service safety and service life of cables laid in complex environments. Detailed Implementation

[0020] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0021] Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commercially available industrial-grade raw materials; the test methods used, unless otherwise specified, are all conventional test methods in the art and national / industry standard methods.

[0022] Example 1 This embodiment prepares pH-responsive tannic acid capsules, and the specific steps are as follows: A1: Preparation of wall material solution: Weigh 20.0g of methacrylic acid-ethyl acrylate copolymer powder (methacrylic acid to ethyl acrylate mass ratio 1:1), slowly add it to 380g of anhydrous ethanol / deionized water mixed solvent with a volume ratio of 7:3, place it in a constant temperature water bath at 40℃, and magnetically stir at a speed of 300r / min until the polymer is completely dissolved to obtain a clear and transparent wall material solution with a mass fraction of about 5%; A2: Emulsion preparation: Weigh 8.0g of industrial grade tannic acid (purity ≥90%) and add it to the above wall material solution. At the same time, add 0.5g of emulsifier Tween-80. Use a high-speed shear emulsifier to emulsify for 5min at a speed of 8000r / min to form a stable oil-in-water emulsion. Microscopic observation shows that the oil phase droplets of the emulsion have uniform particle size and are distributed in the range of 5~15μm. A3: Spray drying granulation: The above emulsion is immediately fed into a spray dryer, and the process parameters are set as follows: inlet air temperature 150℃, outlet air temperature 75℃, peristaltic pump speed 15r / min, spray pressure 0.2MPa. Microcapsule powder is obtained after spray drying. A4: Post-processing: The collected microcapsule powder was placed in a vacuum drying oven at 40℃ and dried for 4 hours to remove residual solvent and moisture, resulting in tannic acid capsules, which were light yellow to brownish-yellow free-flowing powders with a particle size distribution concentrated in the range of 5~20μm.

[0023] Example 2 The difference between this embodiment and Embodiment 1 is that the emulsification time in step A2 is 8 minutes; and the spray drying parameters in step A3 are: inlet air temperature 160°C, outlet air temperature 85°C, peristaltic pump speed 20 r / min, and spray pressure 0.25 MPa. The final tannic acid capsules have a particle size distribution concentrated in the range of 8~20 μm and exhibit good flowability.

[0024] Example 3 This embodiment prepares amylase-responsive cross-linking promoter capsules with ferric citrate as the core material. The specific steps are as follows: B1: Preparation of composite wall material solution: Weigh 4.0g of chitosan (degree of deacetylation ≥85%, viscosity <200mPa·s), dissolve it in 196g of 1% glacial acetic acid solution, and stir magnetically until completely dissolved to obtain a 2% chitosan-acetic acid solution; weigh 4.0g of sodium alginate, dissolve it in 196g of deionized water, and stir in a 50℃ water bath until completely dissolved to obtain a 2% sodium alginate aqueous solution; mix 100g of each of the above two solutions in equal volumes, and stir evenly in a 40℃ water bath to obtain a chitosan-sodium alginate composite wall material solution; B2: Core material dispersion: Weigh 10.0g of ferric citrate and add it to 190g of the above composite wall material solution. Stir until it is completely and evenly dispersed to obtain a core material-wall material mixture. B3: Cross-linking and solidification into capsules: Weigh 5.0g of anhydrous calcium chloride and dissolve it in 1000g of deionized water to prepare a 0.5% calcium chloride aqueous solution as a coagulation bath; load the core material-wall material mixture into an injection pump and drip it into the calcium chloride coagulation bath with continuous stirring (200r / min) at a constant speed through a 0.45mm diameter fine needle, controlling the dripping height at 12cm; the droplets immediately undergo a cross-linking reaction upon contact with calcium ions, solidifying to form spherical microcapsules; B4: Post-processing: After the addition is complete, the microcapsules are allowed to stand and solidify in the coagulation bath for 30 minutes, then filtered and washed repeatedly with deionized water 3 times to remove free calcium ions on the surface; the washed microcapsules are placed in a freeze dryer at -50℃ and freeze-dried for 24 hours until constant weight is obtained to obtain the crosslinking accelerator capsule product, which is light yellow to brown spherical particles with a particle size range of 10~30μm.

[0025] Example 4 The difference between this embodiment and Embodiment 3 is that: in step B3, the needle diameter is 0.6 mm and the dropping height is 15 cm; in step B4, the standing curing time is 60 min and the freeze-drying time is 48 h. The final crosslinking accelerator capsules have a particle size range of 15~30 μm and good sphericity.

[0026] Example 5 This embodiment prepares a rodent- and ant-resistant cable sheath material with repair function. The formula, by weight, consists of: high-density polyethylene (HDPE, injection molding grade, melt index 2.0 g / 10 min): 100 parts; tannic acid capsules obtained in Example 1: 10 parts; crosslinking accelerator capsules obtained in Example 3: 8 parts; dispersant (polyethylene wax): 2 parts; antioxidant (1010 / 168 composite system, mass ratio 1:1): 0.5 parts; carbon black masterbatch: 2 parts. The preparation method includes the following steps: S1: Premixing: Place the HDPE granules in an 80℃ forced-air drying oven and dry for 2 hours. Weigh each component according to the above formula ratio, put them into a high-speed mixer, and mix at 500r / min for 10 minutes at room temperature to make the components evenly dispersed and obtain the mixture. S2: Melt blending and granulation: The mixture is added to a co-rotating parallel twin-screw extruder for melt blending. The extrusion process parameters are set as follows: Zone 1 temperature 150℃, Zone 2 temperature 160℃, Zone 3 temperature 170℃, Zone 4 temperature 170℃, die head temperature 165℃, and screw speed 150r / min. The extruded strip is cooled in a water tank, air-dried, and then fed into a pelletizer to obtain functionalized HDPE sheath material. S3: Co-extrusion molding of the sheath: The functionalized HDPE sheath material is dried in an 80℃ forced-air drying oven for 4 hours. A double-layer co-extrusion process is adopted, in which the HDPE structural layer material and the functionalized HDPE sheath material are fed into two single-screw extruders respectively, and extruded on the surface of the cable core material to be covered. The extrusion temperature of the functionalized HDPE sheath material is as follows: feeding section 150℃, compression section 165℃, metering section 170℃, die head temperature 170℃, screw speed controlled at 25r / min, and the total thickness of the sheath is adjusted to 2.0mm by adjusting the traction speed, of which the repair layer thickness is 0.8mm and the structural layer thickness is 1.2mm. After the extruded sheath is cooled in a water tank and tested by spark, it is wound up to obtain the finished cable sheath.

[0027] Example 6 The difference between this embodiment and embodiment 5 is that the amount of tannic acid capsules added is 5 parts, the amount of crosslinking promoter capsules added is 3 parts, and the remaining components and preparation process are the same as in embodiment 5.

[0028] Example 7 The difference between this embodiment and embodiment 5 is that the amount of tannic acid capsules added is 15 parts, the amount of crosslinking promoter capsules added is 10 parts, and the remaining components and preparation process are the same as in embodiment 5.

[0029] Comparative Example 1 This comparative example is a common HDPE cable sheath, with a formula of only 100 parts HDPE, 2 parts polyethylene wax, 0.5 parts antioxidant, and 2 parts carbon black masterbatch. The preparation process is the same as in Example 5, and it does not contain any functional microcapsules or rodent-repellent additives. It serves as a blank control.

[0030] Comparative Example 2 The only difference between this comparative example and Example 5 is that only 10 parts of tannic acid capsules are added to the formula, and no cross-linking promoter capsules are added. The remaining components and preparation process are the same as in Example 5.

[0031] Comparative Example 3 The only difference between this comparative example and Example 5 is that tannic acid capsules and cross-linking promoter capsules are not added to the formulation, but are replaced with 5 parts of commercially available capsaicin microcapsules for rodent and ant control. All other components and preparation processes are the same as in Example 5.

[0032] Cable sheath samples prepared in Example 1 and Comparative Examples 1-3 were subjected to performance tests according to the corresponding national / industry standards. The test items, test standards, and test results are shown in Table 1 below. Specifically, the saliva-triggered self-healing test involved preparing a simulated saliva solution based on the main components of rodent saliva. The specific formula was: 0.5g mucin, 0.8g sodium chloride (NaCl), 0.2g potassium chloride (KCl), 0.1g sodium dihydrogen phosphate (NaH2PO4), 0.1g urea, and 0.05g amylase. These were dissolved in deionized water and brought to a final volume of 100mL. The pH was adjusted to 7.0±0.1 using 0.1mol / L hydrochloric acid or sodium hydroxide solution. This simulated saliva was stored at 4℃ and brought to room temperature before use. The sheath material to be tested was pressed into a 2.0mm thick sheet on a flat vulcanizing machine and cut into Type 5 dumbbell-shaped specimens conforming to GB / T 1040.3-2006. In the middle of each sample, a 5mm long scratch with a depth of about 50% of the sheet thickness (i.e., 1.0mm) and a length of about 5mm was made perpendicular to the stretching direction using a sterile scalpel blade as an artificial simulated damage.

[0033] Place the prepared scratched sample in a clean petri dish. Using a micropipette, draw 50 μL of simulated rodent saliva and evenly drop it onto the scratched area, ensuring the saliva completely soaks into the damaged area. Place the petri dish in a constant temperature and humidity chamber and allow it to stand for 24 hours at 37°C and 95% relative humidity for repair. After repair, gently blot away any residual liquid on the surface with filter paper and allow it to air dry at room temperature for 2 hours.

[0034] After the repaired specimens were placed in a standard laboratory environment (temperature 23℃±2℃, relative humidity 50%±5%) for 24 hours, tensile tests were performed using a universal testing machine at a tensile speed of 100 mm / min according to GB / T 1040.3-2006. The tensile strength of the specimens was recorded, and the tensile strength retention rate was calculated. A tensile strength retention rate ≥70% and microscopic observation shows that the scratches have basically healed, indicating good self-repair effect; a tensile strength retention rate between 50% and 70% and partial healing of the scratches, indicating some self-repair ability; a tensile strength retention rate <50% and no significant change in the scratches, indicating no self-repair ability.

[0035] Table 1

[0036] As shown in Table 1 above, the sheath material prepared in Example 5 of this invention meets the industry requirements for cable sheath materials in terms of tensile strength, elongation at break, thermal aging performance, environmental stress cracking resistance, and volume resistivity. Compared with the blank HDPE sheath, its basic performance is not significantly degraded, proving that the functional microcapsules have good compatibility with the HDPE matrix and can be adapted to the service requirements of existing cable sheaths. In a simulated rodent saliva environment, Example 5 exhibits excellent self-healing ability. Scratches can be completely healed, and the tensile strength retention rate after repair reaches 86%, which is significantly better than Comparative Example 1 and Comparative Example 3 without repair function. In contrast, Comparative Example 2, which only added tannic acid capsules, can only achieve partial physical filling, and the repair layer is loose with low strength retention rate, indicating the synergistic effect of the two-component microcapsules and the metal ionization Cross-linking reinforcement is a core and necessary condition for achieving high-strength permanent repair. Rodent and ant repellency tests show that Example 5, Comparative Examples 2 and 3 all passed standard tests, proving that tannic acid and traditional capsaicin have good rodent and ant repellency effects. The core advantage of Example 5 is that even if a small amount of biting occurs, the damaged area can be self-repaired by saliva, forming a full-chain protection of "repellency-repair-secondary protection". This completely solves the industry pain point that traditional repellent sheaths lose their protective ability once damaged. At the same time, the dual-response microcapsule system will only fully release the core material under the dual conditions of pH environment and amylase in rodent and ant saliva. This can effectively avoid non-target false triggering caused by soil pH fluctuations and conventional mechanical scratches, ensuring the stability of the self-healing system during long-term underground service.

Claims

1. A rodent- and ant-proof cable sheath material with repair function, characterized in that, From the inside out, it includes a structural layer and a repair layer; the structural layer is made of high-density polyethylene material. The repair layer uses high-density polyethylene as a matrix, in which two-component microcapsules are uniformly dispersed; the two-component microcapsules include tannic acid capsules and cross-linking accelerator capsules; The core material of the tannic acid capsule is tannic acid or its derivative, and the wall material is a pH-responsive polymer. The wall material of the tannic acid capsule dissolves or swells in a slightly acidic to neutral environment with a pH value > 5.

5. The core material of the crosslinking accelerator capsule is a metal ion crosslinking agent, and the wall material is an enzyme-responsive polymer. The wall material of the crosslinking accelerator capsule can be specifically degraded by amylase in saliva.

2. The rodent- and ant-proof cable sheath material with repair function according to claim 1, characterized in that, The pH-responsive polymer is a methacrylic acid-ethyl acrylate copolymer obtained by copolymerizing methacrylic acid and ethyl acrylate in a mass ratio of 1:

1.

3. The rodent- and ant-proof cable sheath material with repair function according to claim 1, characterized in that, The metal ion crosslinking agent is ferric citrate, and the enzyme-responsive polymer is a chitosan-sodium alginate complex.

4. The rodent- and ant-proof cable sheath material with repair function according to claim 1, characterized in that, The tannic acid capsules are prepared using the following steps: A1: Weigh out the methacrylate-ethyl acrylate copolymer powder and slowly add it to an anhydrous ethanol / water mixed solvent with a volume ratio of 7:

3. Stir at 300 r / min in a constant temperature water bath at 40℃ until the polymer is completely dissolved to obtain a clear and transparent wall material solution. A2: Weigh out tannic acid and add it to the wall material solution. At the same time, add emulsifier and emulsify for 5-8 minutes using a high-speed shear emulsifier at a speed of 8000r / min to form a stable oil-in-water emulsion. A3: The water-in-oil emulsion is spray-dried at an inlet air temperature of 150~160℃, an outlet air temperature of 75~85℃, a peristaltic pump speed of 15~20r / min, and a spray pressure of 0.2~0.25MPa to obtain microcapsule powder. The microcapsule powder is then dried in a vacuum drying oven at 40℃ for 4 hours to obtain tannic acid capsules.

5. The rodent- and ant-proof cable sheath material with repair function according to claim 4, characterized in that, The emulsifier is Tween-80; the ratio of methacrylate-ethyl acrylate copolymer powder, anhydrous ethanol / water mixed solvent, tannic acid and emulsifier is 20g:380g:8g:0.5g.

6. The rodent- and ant-proof cable sheath material with repair function according to claim 1, characterized in that, The crosslinking accelerator capsules are prepared using the following steps: B1: Weigh out chitosan and dissolve it in 1% glacial acetic acid solution to prepare a chitosan-acetic acid solution with a chitosan concentration of 2%; weigh out sodium alginate and dissolve it in deionized water to prepare a sodium alginate aqueous solution of 2%; mix equal volumes of chitosan-acetic acid solution and sodium alginate aqueous solution and stir evenly at 40℃ to obtain chitosan-sodium alginate composite wall material solution. B2: Take ferric citrate and disperse it evenly into the chitosan-sodium alginate composite wall material solution to obtain a core material-wall material mixture; B3: Dissolve anhydrous calcium chloride in deionized water to prepare a 0.5% calcium chloride aqueous solution; drip the core material-wall material mixture into the calcium chloride aqueous solution under continuous stirring at 200 r / min through a fine needle with a diameter of 0.4~0.6 mm at a constant speed, and the dripping height is 10~15 cm; when the core material-wall material mixture comes into contact with calcium ions, a cross-linking reaction occurs immediately, and it solidifies into spherical microcapsules; B4: After the addition is complete, let it stand for 30-60 minutes to solidify, then filter and wash with deionized water. Then freeze-dry at -50℃ for 24-48 hours until constant weight is obtained to obtain dried crosslinking accelerator capsules.

7. The rodent- and ant-proof cable sheath material with repair function according to claim 6, characterized in that, The ratio of chitosan-sodium alginate composite wall material solution to ferric citrate is 190g:10g.

8. A method for preparing a rodent- and ant-proof cable sheath material with repair function as described in any one of claims 1 to 7, characterized in that, The following steps are used: S1: Dry 100 parts of high-density polyethylene at 80°C for 2 hours, and mix the dried high-density polyethylene with 5-10 parts of tannic acid capsules, 3-10 parts of crosslinking accelerator capsules, 1-3 parts of dispersant and 0.5-1 parts of antioxidant at 500r / min for 10 minutes at room temperature. S2: The mixed materials are added to a co-rotating parallel twin-screw extruder for melt blending. The extruded strips are cooled in a water tank, air-dried, and then granulated to obtain functionalized HDPE sheath material. S3: After drying the functionalized HDPE sheath material at 80℃ for 4 hours, use a co-extrusion process to feed the high-density polyethylene and functionalized HDPE sheath material into a single screw extruder and extrude them onto the surface of the core material to be coated.

9. The preparation method according to claim 8, characterized in that, In step S2, the process parameters for melt blending are set as follows: zone 1 temperature 150℃, zone 2 temperature 160℃, zone 3 temperature 170℃, zone 4 temperature 170℃, die head temperature 165℃, and screw speed 150r / min.

10. The preparation method according to claim 8, characterized in that, In step S3, the extrusion temperature is set as follows: 150°C for the feeding section, 165°C for the compression section, 170°C for the metering section, and 170°C for the die head. The screw speed is controlled at 20~30 r / min.

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