A rodent and termite resistant cable and its preparation method and application

Abstract

The application provides a kind of rat and termite prevention cable and its preparation method and application, belong to cable material technical field.The rat and termite prevention cable includes cable core and sheath layer, nylon wrapping layer and sacrificial layer successively covered on the surface of the cable core;The cable core includes at least one conductive wire core;The conductive wire core includes conductor and insulating layer covered on the surface of the conductor;The nylon wrapping layer is formed by wrapping the surface of the sheath layer with nylon wrapping tape;The nylon wrapping tape is prepared by the following method, the method comprises: melting extrusion, gradient calendering of nylon, to obtain the nylon wrapping tape;The gradient calendering includes first stage, second stage and third stage successively;The first stage calendering temperature> third stage calendering temperature> second stage calendering temperature.The rat and termite prevention cable can prevent rats and termites while considering excellent bending performance, and is light in weight, low in cost, environmentally friendly and harmless.

Description

Technical Field

[0001] This application belongs to the field of cable material technology, specifically relating to a rodent-proof cable, its preparation method, and its application. Background Technology

[0002] In the fields of power, communications, and rail transportation, cables, as critical infrastructure, have long faced the dual challenges of natural environmental damage and biological infestation. Among these, rodent gnawing and ant infestation are significant contributing factors to cable failures, particularly in tropical, subtropical, and humid warm regions.

[0003] Currently, traditional rodent- and termite-proof cable structures involve extruded nylon layers or the application of metal armor layers, or the addition of rodent repellents (such as capsaicin) or termite repellents (such as pyrethroids) to the sheath material. However, these methods all have limitations. For example, when using extruded nylon layers as a rodent- and termite-proof structure, the neutral layer offset increases dramatically during bending, easily forming severe accumulation wrinkles on the inner side of the bend. On the outer side of the bend, the material's elongation at break exceeds its limit, easily leading to cracks or even breakage, significantly reducing the cable's bending performance. Metal armor layers, as a rodent- and termite-proof structure, increase cable weight, enlarge the cable's outer diameter, and increase cable cost, making them ineffective in situations where weight and outer diameter are limited. Furthermore, using metal armor solely for rodent- and termite-proofing results in resource waste and reduces product competitiveness. Additionally, adding chemical repellents to the sheath material can harm the health of operators during cable production and installation, and also pollute the surrounding environment.

[0004] Therefore, developing a rodent- and ant-proof cable with excellent bending performance, light weight, low cost, and no impact on the environment and human health is an urgent problem to be solved in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a rodent-proof cable and its preparation method; the rodent-proof cable solves the problems of poor bending performance, large weight and outer diameter, high cost, and negative impact on human health and the environment in existing rodent-proof cables.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a rodent-proof cable, the rodent-proof cable comprising a cable core and a sheath layer, a nylon wrapping layer, and a sacrificial layer sequentially covering the surface of the cable core; the cable core comprises at least one conductive core; the conductive core comprises a conductor and an insulating layer covering the surface of the conductor; the nylon wrapping layer is formed by wrapping nylon wrapping tape around the surface of the sheath layer; the nylon wrapping tape is prepared by the following method, the method comprising: melting and extruding nylon and gradient calendering to obtain the nylon wrapping tape; the gradient calendering comprises a first stage, a second stage, and a third stage performed sequentially; the calendering temperature of the first stage > the calendering temperature of the third stage > the calendering temperature of the second stage.

[0008] In this invention, the rodent-proof cable utilizes a nylon wrapping layer on the surface of the sheath as its core rodent-proof structure. During bending, the nylon wrapping layer provides ample sliding space, allowing the cable to undergo repeated bending and straightening movements in any direction without permanent damage to the nylon wrapping structure, significantly improving the cable's bending performance. Secondly, compared to metal armor layers for rodent and ant protection, this design effectively reduces the product's outer diameter, weight, and cost. Furthermore, it eliminates the need for chemical repellents such as capsaicin, making it health-friendly for operators during cable production and installation, and preventing environmental pollution.

[0009] Furthermore, the nylon wrapping tape prepared using a specific process in this invention can adjust the microstructure and properties of the nylon material, which is beneficial for further improving the bending performance of the cable. Specifically, through gradient calendering, i.e., performing a three-stage thermodynamic treatment on the nylon at different temperatures, the first stage rearranges the molecular chains under micro-stretching to form a preliminary orientation structure; the second stage rapidly crosses the "maximum crystallization rate temperature zone" of nylon, inhibiting the formation of large spherulites and instead forming a fine pseudo-hexagonal crystal system, which is beneficial for improving the toughness of the material. The third stage eliminates the thermal shrinkage stress caused by temperature difference, achieving dimensional stability. The three-stage thermodynamic treatment eliminates the inherent "isotropic shrinkage stress" of nylon material, making the nylon tape exhibit the "flexibility" of textiles rather than the "brittleness" of plastics when repeatedly bent, completely solving the industry-wide problem of wrinkling, accumulation, and even cracking of the nylon structure when the cable is bent.

[0010] In this invention, the material of the nylon wrapping tape includes at least one of nylon 12, nylon 6, nylon 11, nylon 1010, nylon 610, and nylon 612.

[0011] In this invention, the width of the nylon wrapping tape is 20~50mm, for example, it can be 22 mm, 24 mm, 26 mm, 28 mm, 30 mm, 32 mm, 34 mm, 36 mm, 38 mm, 40 mm, 42 mm, 44 mm, 46 mm, 48 mm, etc.

[0012] In this invention, the surface tension of the nylon wrapping tape is 38~42 dyn / cm, for example, it can be 38.5 dyn / cm, 39 dyn / cm, 39.5 dyn / cm, 40 dyn / cm, 40.5 dyn / cm, 41 dyn / cm, 41.5 dyn / cm, etc.

[0013] In this invention, the tensile strength of the nylon wrapping tape is 55~65MPa, for example, it can be 56 MPa, 57 MPa, 58 MPa, 59 MPa, 60 MPa, 61 MPa, 62 MPa, 63 MPa, 64 MPa, etc.; the elongation at break is 300~400%, for example, it can be 310%, 320%, 340%, 350%, 360%, 370%, 380%, 390%, etc.

[0014] In this invention, the thickness of the nylon wrapping layer is 0.2~0.3 mm, for example, it can be 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.27 mm, 0.28 mm, 0.29 mm, etc.

[0015] In this invention, the overlap rate of the nylon wrapping layer is 5-50%, for example, it can be 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, etc.

[0016] In this invention, the thickness of the nylon wrapping layer is too large, which affects flexibility; the overlap ratio is too high, which affects bending performance.

[0017] In this invention, the rolling temperature of the first stage is 85~95℃, for example, it can be 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃, etc.; the rolling temperature of the second stage is 10~15℃, for example, it can be 10.5℃, 11℃, 11.5℃, 12℃, 12.5℃, 13℃, 13.5℃, 14℃, 14.5℃, etc.; the rolling temperature of the third stage is 45~55℃, for example, it can be 46℃, 47℃, 48℃, 49℃, 50℃, 51℃, 52℃, 53℃, 54℃, etc.

[0018] In this invention, the gas pressure of the first stage of calendering is 0.3~0.5MPa, for example, it can be 0.32 MPa, 0.34 MPa, 0.36 MPa, 0.38 MPa, 0.4 MPa, 0.42 MPa, 0.44 MPa, 0.46 MPa, 0.48 MPa, etc.

[0019] In this invention, the rolling speed of the first stage > the rolling speed of the second stage > the rolling speed of the third stage.

[0020] In this invention, the rolling speed in the first stage is 7.4~9.5 m / min, for example, it can be 7.5 m / min, 7.6 m / min, 7.8 m / min, 8 m / min, 8.2 m / min, 8.4 m / min, 8.6 m / min, 8.8 m / min, 9 m / min, 9.2 m / min, 9.4 m / min, etc.; the rolling speed in the second stage is 7~9 m / min, for example, it can be 7.2 m / min, 7.4 m / min, 7.6 m / min, 7.8 m / min, 8 m / min, 8.2 m / min, 8.4 m / min, 8.6 m / min, 8.8 m / min, etc.; the rolling speed in the third stage is 6.5~8.8 m / min, for example, it can be 6.6 m / min, 6.8 m / min, 7 m / min, 7.2 m / min, 7.4 m / min, 7.6 m / min, 7.8 m / min, 8 m / min, etc. m / min, 8.2 m / min, 8.4 m / min, 8.6m / min, etc.

[0021] In this invention, the rolling speed in the first stage is 0.9 to 1.2, for example, it can be 0.92, 0.94, 0.96, 0.98, 1, 1.02, 1.04, 1.05, 1.06, 1.08, 1.1, 1.12, 1.15, 1.18, etc.; the rolling speed in the second stage is 0.87 to 1.13, for example, it can be 0.88, 0.9, 0. The rolling speeds in the third stage are 0.92, 0.94, 0.96, 0.98, 1, 1.02, 1.04, 1.06, 1.08, 1.1, 1.12, etc.; the rolling speed in the third stage is 0.85 to 1.1, for example, 0.86, 0.88, 0.9, 0.92, 0.94, 0.96, 0.98, 1, 1.02, 1.04, 1.06, 1.08, etc.

[0022] In this invention, a three-roll vertical calender is used for gradient calendering. The three-roll vertical calender includes a first roll, a second roll, and a third roll. The first roll is used for the first stage of calendering; the second roll is used for the second stage of calendering; and the third roll is used for the third stage of calendering. The roll surfaces of the three-roll vertical calender are mirror-plated with chrome, and the roughness Ra ≤ 0.05 μm.

[0023] In this application, the calendering speed ratio refers to the ratio of the linear velocity of each roll to the nylon extrusion speed.

[0024] In this invention, an air knife is provided above the contact point between the melt and the roller surface in the first roller, and the air pressure is controlled at 0.3~0.5MPa to force the melt to adhere to the first roller and prevent air from being trapped and generating bubbles.

[0025] In this invention, the water content of the nylon is 0.02~0.04 wt%, for example, it can be 0.025 wt%, 0.03 wt%, 0.035 wt%, etc.

[0026] In this invention, the step of drying the nylon before melt extrusion is further included, so that the moisture content of the nylon is 0.02~0.04wt%, to avoid the nylon hydrolysis and chain breakage caused by excessive moisture content during extrusion; the drying method includes: using a dehumidifying dryer with a dew point of -40℃, putting the nylon into the equipment, setting the drying temperature to 120±5℃, the dew point temperature to ≤-40℃, and the drying time to 4~6h.

[0027] In this invention, the temperature of the melt extrusion is 180~260℃, for example, it can be 190℃, 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, etc.; the rotation speed is 120~150rpm, for example, it can be 125 rpm, 130 rpm, 135 rpm, 140 rpm, 145 rpm, etc.

[0028] In this invention, the melt extrusion is carried out in a twin-screw extruder with a length-to-diameter ratio (L / D) ≥ 36:1. The melt extrusion employs a stepped melt extrusion temperature, including a feeding section, a melting section, and a final section. The temperature of the feeding section (zone 1) is 180~190℃, the temperature of the melting section (zone 2) is 210~220℃, and the temperature of the final section (zone 3) is 235~240℃, ensuring thorough melting and homogenization of the nylon. The pressure at the die head of the twin-screw extruder is 12~15 MPa.

[0029] In this invention, the material after melt extrusion is fed into a three-roll vertical calender after passing through a die head. The die head is a customized micro-coat hanger type die head with an effective die lip length of 80mm, a die lip width of 60mm, a die head temperature of 250±2℃, and a die lip opening set to 0.4~0.45mm. It is equipped with 16-point hydraulic fine-tuning bolts, which are used to adjust the die lip gap to ensure that the material is discharged slightly faster in the middle and slightly slower on both sides, in order to compensate for the subsequent necking effect and ensure that the width of the final nylon wrapping tape is stable within the range of 20~50mm.

[0030] In this invention, the gradient rolling process further includes a corona treatment step.

[0031] In this invention, before the corona treatment, there is also a step of trimming the edges; specifically, a rotary cutter is used to remove the unstable edges (the width is cut to the target size), and the cut must be inspected under a microscope to ensure there are no microscopic cracks.

[0032] In this invention, the voltage of the corona treatment is 10~15kV, for example, it can be 10.5 kV, 11 kV, 11.5 kV, 12 kV, 12.5 kV, 13 kV, 13.5 kV, 14 kV, 14.5 kV, etc.; the frequency is 10~30kHz, for example, it can be 12 kHz, 14 kHz, 16 kHz, 18 kHz, 20 kHz, 22 kHz, 24 kHz, 26 kHz, 28 kHz, etc.

[0033] In this invention, corona treatment reduces the surface tension of the nylon wrapping tape to 38-42 dyn / cm, which helps to enhance interlayer adhesion during subsequent wrapping.

[0034] In this invention, the conductor includes any one of Class I, Class II, Class V, or Class VI conductors.

[0035] In this invention, the conductor comprises a copper conductor; the conductor's weighing cross-sectional area is 1.5~630 mm². 2 The outer diameter of the conductor is 1.5~40mm.

[0036] In some specific embodiments of the present invention, the conductor is prepared by the following method, which includes: drawing a copper rod with a diameter of Φ8mm into a copper single wire of 0.290~0.293mm, wherein the elongation of the copper single wire is ≥35% and the resistivity of the copper single wire is not more than 0.017241Ω·mm. 2 / m; then a bundling machine is used to bundle several copper monofilaments into strands, with the bundling direction to the left and the outer diameter of the strands being 0.5-5mm; a cage stranding machine is used to strand at least one strand into a conductor, with the stranding direction to the left and the ratio of the outermost layer of the conductor's twisted section diameter controlled at 13 to 15 times.

[0037] In this invention, the nominal thickness of the insulating layer is 0.7~3.0 mm, for example, it can be 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, etc.

[0038] In this invention, the average thickness of the insulating layer is not less than the nominal thickness, and the thickness at the thinnest point is not less than (90% of the nominal thickness - 0.1) mm.

[0039] In this invention, the material of the insulating layer includes at least one of cross-linked polyolefin or cross-linked elastomer.

[0040] In this invention, the material of the insulating layer is resistant to high temperature of 110°C.

[0041] In this invention, the nominal thickness of the sheath layer is 1.8~3.5mm, for example, it can be 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, 3 mm, 3.2 mm, 3.4 mm, etc.

[0042] In this invention, the thickness of the thinnest point of the sheath layer is not less than (85% - 0.1) mm.

[0043] In this invention, the nominal thickness of the sacrificial layer is 1.2~2.5 mm, for example, it can be 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.4 mm, etc.

[0044] In this invention, the thickness of the thinnest point of the sacrificial layer is not less than (80% of the nominal thickness - 0.2) mm.

[0045] In this invention, the materials of the sheath layer and the sacrificial layer each independently include low-smoke halogen-free polyolefin.

[0046] In this invention, the materials of the sheath layer and the sacrificial layer are heat-resistant to 110°C.

[0047] In this invention, the cable core further includes a filling layer and a second wrapping layer covering the conductive core and the surface of the filling layer.

[0048] In this invention, the rodent-proof cable can be a single-core cable or a multi-core cable; when the cable core consists of a single conductive core, it is a single-core cable; when the cable core includes at least two conductive cores, the at least two conductive cores, together with the filler layer and the second wrapping layer, constitute a multi-core cable; the filler layer fills the gaps between the conductive cores.

[0049] In this invention, the filling layer is made of polypropylene mesh tear fibers.

[0050] In this invention, the filling layer is made of polypropylene mesh tear-fiber filling rope.

[0051] In this invention, the material of the filling layer does not exhibit embrittlement after being aged at 120℃±2℃ for 240 hours.

[0052] In this invention, the material of the second wrapping layer includes nonwoven fabric; specifically, it includes reinforced nonwoven fabric; the overlap rate of the second wrapping layer is 5~20%, for example, it can be 6%, 8%, 10%, 12%, 14%, 16%, 18%, etc.

[0053] In this invention, when the anti-rodent cable is a multi-core cable, the cable core is cabled in a right-hand direction, the cable is cabled by untwisting method, and the cable section diameter ratio is 20~25.

[0054] In some specific embodiments of the present invention, the rodent-proof cable is a single-core cable with a nylon wrapping layer having a wrapping specification of 0.2mm (thickness) × 30mm (width) and a wrapping overlap width of 3.0mm-4.5mm; the rodent-proof cable is a multi-core cable with a nylon wrapping layer having a wrapping specification of 0.2mm (thickness) × 50mm (width) and a wrapping overlap width of 5.0mm-7.5mm.

[0055] Secondly, the present invention provides a method for preparing the rodent- and ant-proof cable according to the first aspect, the method comprising the following steps:

[0056] A sheath layer, a nylon wrapping layer, and a sacrificial layer are sequentially disposed on the surface of the cable core to obtain the rodent-proof cable.

[0057] In this invention, the method for preparing the conductive wire core includes: extruding the insulating layer material onto the surface of the conductor, irradiating it, and obtaining the conductive wire core.

[0058] In this invention, the extrusion temperature is 120~170℃, for example, it can be 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, etc.

[0059] In this invention, the irradiation energy is 1~4 MeV, for example, 1.2 MeV, 1.5 MeV, 1.8 MeV, 2 MeV, 2.2 MeV, 2.5 MeV, 2.8 MeV, 3 MeV, 3.2 MeV, 3.5 MeV, 3.8 MeV, etc.; the number of passes is 10~20, for example, 12, 14, 16, 18, etc.; the beam current is 20~30 mA, for example, 22 mA, 24 mA, 26 mA, 28 mA, etc.; and the linear velocity is 5~15 m / min, for example, 6 m / min, 8 m / min, 10 m / min, 12 m / min, 14 m / min, etc.

[0060] In this invention, the preparation method includes: extruding the material of the sheath layer and covering it on the surface of the cable core to obtain the sheath layer; wrapping nylon wrapping tape around the surface of the sheath layer to obtain the nylon wrapping layer; and extruding the material of the sacrificial layer and covering it on the surface of the nylon wrapping layer to obtain the rodent-proof cable.

[0061] In this invention, a sheath layer and a sacrificial layer are obtained, and the extrusion temperature is independently 130~175℃, for example, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, etc.

[0062] In this invention, the rodent-proof cable is a single-core cable, and the preparation method of the sheath layer and the sacrificial layer uses a Φ120 extruder; the rodent-proof cable is a multi-core cable, and the preparation method of the sheath layer and the sacrificial layer uses a Φ150 extruder.

[0063] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0064] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0065] The rodent-proof cable provided by this invention has a nylon wrapping layer formed by setting a specific nylon wrapping tape on the surface of the sheath layer. It is not only rodent-proof but also has excellent bending performance. It can effectively reduce the outer diameter of the product, reduce the weight of the product, and reduce the cost. It does not require the addition of chemical repellents such as capsaicin. It is friendly to the health of operators during cable production and installation and will not cause pollution to the surrounding environment. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of the structure of the rodent-proof cable provided in Embodiment 1 of the present invention;

[0067] Among them, 1-conductor layer; 2-insulating layer; 3-sheath layer; 4-nylon wrapping layer; 5-sacrificial layer.

[0068] Figure 2 This is a schematic diagram of the structure of the rodent-proof cable provided in Embodiment 2 of the present invention;

[0069] Among them, 1-conductor layer; 2-insulating layer; 3-filler layer; 4-non-woven fabric wrapping layer; 5-sheath layer; 6-nylon wrapping layer; 7-sacrificial layer.

[0070] Figure 3 A flowchart of the manufacturing process of the nylon wrapping tape provided by the present invention;

[0071] Among them, 8-dehumidifying dryer, 9-twin-screw extruder, 10-coat hanger type T-die head, 11-three-roll vertical calender, 12-edge trimming and corona treatment, 13-tension winding machine. Detailed Implementation

[0072] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0073] All materials used in this invention can be purchased commercially or prepared using conventional methods.

[0074] Preparation Example 1

[0075] This preparation example provides a nylon wrapping tape, and the process flow diagram of the nylon wrapping tape preparation device is shown below. Figure 3 As shown, the specific steps include:

[0076] (1) Nylon 12 (Swiss EMS L25W40X) was put into a dehumidifying dryer 8 with a dew point of -40℃. The drying temperature was set to 120℃, the dew point temperature to -45℃, and the drying time to 4 hours, so that the output moisture content was controlled at 0.02%-0.04% and ready for use.

[0077] (2) A 45mm co-rotating twin-screw extruder 9 (length-to-diameter ratio L / D=40:1) is used for melt extrusion. The extrusion speed of nylon 12 is 8m / min. It is sent to a three-roll vertical calender 11 through the die head 10 for gradient calendering.

[0078] The twin-screw extruder has a zone temperature set at 185℃, a zone temperature set at 215℃, and a zone temperature set at 245℃. The die head pressure is controlled between 12MPa and 15MPa. The die head is a coat hanger-type T-die head with an effective die lip length of 80mm and a die lip width of 60mm. It is equipped with 16 hydraulic micro-adjustment bolts to adjust the die lip gap and ensure that the final nylon wrapping tape width is stable within the range of 30~50mm. The die head temperature is set at 252℃, and the die lip opening is 0.45mm.

[0079] In a three-roll vertical calender, the first roll is set at a temperature of 90℃ and a calendering speed of 8.4 m / min, with a speed multiplier of 1.05. An air knife is installed above the contact point between the melt and the roll surface, with an air pressure set at 0.4 MPa. The second roll is set at a temperature of 12℃ and a calendering speed of 8.0 m / min, with a speed multiplier of 1.0. The third roll is set at a temperature of 50℃ and a calendering speed of 7.8 m / min, with a speed multiplier of 0.98. After calendering, the strip is trimmed, and the trimming width is set to 30 mm or 50 mm according to the cable production requirements.

[0080] (3) The surface of the nylon tape obtained in step (2) is subjected to corona treatment. The voltage is set to 15kV and the frequency is 20kHz. The winding tension is set to 12N. When the roll diameter reaches 100mm, the tension is linearly reduced to 7N. The nylon wrapping tape production is completed, and the nylon wrapping tape is obtained.

[0081] Preparation Example 2

[0082] This preparation example provides a nylon wrapping tape. The difference between the preparation method of the nylon wrapping tape and that of Preparation Example 1 is that nylon 12 is replaced with nylon 6 (Delta PA6-H). In step (2), in the three-roll vertical calender, the temperature of the first roll is set to 85°C and the calendering speed is 9.5 m / min. An air knife is set above the contact point between the melt and the roll surface, and the air pressure is set to 0.3 MPa. The temperature of the second roll is set to 15°C and the calendering speed is 9 m / min. The temperature of the third roll is set to 55°C and the calendering speed is 8.8 m / min. After calendering, the strip is trimmed. The trimming width is set to 30 mm or 50 mm according to the needs of cable production. In step (3), the voltage is set to 10 kV and the frequency is 30 kHz. The other steps are the same as those in Preparation Example 1.

[0083] Preparation Example 3

[0084] This preparation example provides a nylon wrapping tape. The difference between the preparation method of the nylon wrapping tape and that of Preparation Example 1 is that nylon 12 is replaced with nylon 1010 (Double H1010HU). In step (2), in the three-roll vertical calender, the temperature of the first roll is set to 95°C and the calendering speed is 7.4 m / min. An air knife is set above the contact point between the melt and the roll surface, and the air pressure is set to 0.5 MPa. The temperature of the second roll is set to 10°C and the calendering speed is 7 m / min. The temperature of the third roll is set to 45°C and the calendering speed is 6.8 m / min. After calendering, the strip is trimmed. The trimming width is set to 30 mm or 50 mm according to the needs of cable production. In step (3), the voltage is set to 12 kV and the frequency is 15 kHz. The other steps are the same as those in Preparation Example 1.

[0085] Preparation Example 4

[0086] This preparation example provides a nylon wrapping tape. The difference between the preparation method of the nylon wrapping tape and that of Preparation Example 1 is that the temperature of the first roller is set to 70°C, the temperature of the second roller is set to 20°C, and the temperature of the third roller is set to 60°C. All other process parameters are the same as those of Preparation Example 1.

[0087] Preparation Example 5

[0088] This preparation example provides a nylon wrapping tape. The difference between the preparation method of the nylon wrapping tape and that of Preparation Example 1 is that the temperature of the first roller is set to 100°C, the temperature of the second roller is set to 5°C, and the temperature of the third roller is set to 40°C. All other process parameters are the same as those of Preparation Example 1.

[0089] Preparation Example 6

[0090] This preparation example provides a nylon wrapping tape. The difference between the preparation method of the nylon wrapping tape and that of Preparation Example 1 is that the calendering speed of the first roll, the second roll and the third roll are all 8.5 m / min, while other process parameters are the same as those of Preparation Example 1.

[0091] Preparation Example 7

[0092] This preparation example provides a nylon wrapping tape. The difference between the preparation method of the nylon wrapping tape and that of Preparation Example 1 is that the first roll calendering speed is 6 m / min, the second roll calendering speed is 8 m / min, and the third roll calendering speed is 9 m / min. All other process parameters are the same as those of Preparation Example 1.

[0093] Preparation Example 8

[0094] This preparation example provides a nylon wrapping tape. The difference between the preparation method of the nylon wrapping tape and that of preparation example 1 is that the voltage is set to 8kV and the frequency to 35kHz in step (3), while the other process parameters are the same as those in preparation example 1.

[0095] Preparation Example 9

[0096] This preparation example provides a nylon wrapping tape. The difference between the preparation method of the nylon wrapping tape and that of preparation example 1 is that the voltage is set to 20kV and the frequency to 5kHz in step (3), while the other process parameters are the same as those in preparation example 1.

[0097] Comparative Preparation Example 1

[0098] This comparative preparation example provides a nylon wrapping tape. The difference between the preparation method of the nylon wrapping tape and that of Preparation Example 1 is that the temperature of the first roller is set to 90°C, the temperature of the second roller is set to 50°C, and the temperature of the third roller is set to 12°C. All other process parameters are the same as those of Preparation Example 1.

[0099] Comparative Preparation Example 2

[0100] This comparative preparation example provides a nylon wrapping tape. The difference between the preparation method of the nylon wrapping tape and Preparation Example 1 is that the temperature of the first roller, the second roller and the third roller are all set to 90°C, while other process parameters are the same as those in Preparation Example 1.

[0101] Both the preparation examples and the comparative preparation examples of this invention provide two widths of nylon wrapping tape, namely 30mm and 50mm, through edge cutting, for later use. The 30mm tape is used for preparing single-core cables, and the 50mm tape is used for preparing multi-core cables. The thickness, tensile strength, elongation at break, and surface tension of the nylon wrapping tapes provided in the preparation examples and the comparative preparation examples are shown in Table 1.

[0102] In this invention, the surface tension of the nylon wrapping tape is tested using GB / T 14216-2008, employing the dyne pen method; the tensile strength and elongation at break are tested using GB / T 2952.1-2008.

[0103] Table 1

[0104]

[0105] As shown in Table 1, the nylon wrapping tapes prepared by the specific process in Examples 1-5 of this invention have both high tensile strength and elongation at break, and do not exhibit self-adhesion, powdering, embrittlement, or brittle fracture. The resulting tape products are qualified.

[0106] As can be seen from Preparation Examples 1, 4, and 5, using a specific treatment temperature in the three-stage thermodynamic treatment is more conducive to obtaining nylon wrapping tape with high tensile strength and elongation at break.

[0107] As can be seen from Preparation Examples 1, 6, and 7, if a specific calendering speed is not used, the resulting nylon wrapping tape is prone to breakage or the product is unqualified.

[0108] As can be seen from Preparation Examples 1, 8, and 9, without using a specific corona treatment process, the nylon wrapping tape produced self-adhesion, powdering, embrittlement, or decreased tensile strength and elongation at break, as well as poor adhesion and microcracks (Preparation Example 9).

[0109] As can be seen from Preparation Example 1 and Comparative Preparation Examples 1 and 2, the nylon wrapping tape obtained without using a specific three-stage thermodynamic treatment process is prone to breakage or has decreased tensile strength and elongation at break.

[0110] Example 1

[0111] This embodiment provides a rodent-proof cable, the structural schematic diagram of which is shown below. Figure 1 As shown, it consists of a conductor 1 and an insulating layer 2, a sheath layer 3, a nylon wrapping layer 4, and a sacrificial layer 5 sequentially covering the surface of the conductor; the conductor is a copper conductor with a weighing cross-sectional area of ​​300.4 mm². 2 The outer diameter is 23.4 mm, and the DC resistance of the conductor at 20℃ is 0.0635 Ω / km; the insulation layer is made of irradiated cross-linked elastomer insulation material with a temperature resistance of 110℃ (Jiangsu Shangshang Cable Group Co., Ltd. FPJ-110(L405)), and the nominal thickness of the insulation layer is 1.8 mm; the sheath layer is made of 110℃ temperature-resistant, UV-resistant, thermoplastic, low-smoke, halogen-free flame-retardant polyolefin (Fangzhide HFS-110-TP), and the nominal thickness is 1.8 mm; the nylon wrapping layer is made of nylon wrapping tape with a width of 30 mm provided in Preparation Example 1, and the thickness of the nylon wrapping layer is 0.23 mm with an overlap rate of 10%; the sacrificial layer is made of 110℃ temperature-resistant, UV-resistant, thermoplastic, low-smoke, halogen-free flame-retardant polyolefin (Fangzhide HFS-110-TP), and the nominal thickness is 1.2 mm.

[0112] This embodiment provides a method for preparing the rodent-proof cable, specifically including the following steps:

[0113] (1) A copper rod with a diameter of Φ8mm is drawn into a copper monofilament with a diameter of 0.293mm. The elongation of the copper monofilament is 35%, and the resistivity of the copper monofilament is 0.017100Ω•mm. 2 / m; 67 copper monofilaments are bundled together into strands using a bundling machine, with the bundling direction to the left and the outer diameter of the strands being approximately 2.6mm; 61 strands are twisted together into a conductor using a cage stranding machine, arranged in a 1+6+12+18+24 pattern, with the twisting direction to the left, and the outermost layer of the conductor has a twist pitch ratio controlled at 15 times, thus obtaining the conductor;

[0114] (2) Using an 80 extruder, the temperatures of the first to eighth temperature zones of the extruder are set as follows: 120℃, 130℃, 141℃, 154℃, 162℃, 165℃, 165℃, and 165℃ respectively; the temperatures of the three temperature zones of the die head are 175℃, 175℃, and 170℃ respectively. The insulating material is extruded and coated (extruded) onto the surface of the conductor. Then, irradiation is carried out under the conditions of 2.1MeV energy, 14 passes, 25mA beam current, and 10m / min linear speed. After irradiation, a thermal elongation test is carried out. The maximum elongation under load is detected to be 60%, and the maximum permanent elongation after cooling is 0%, thus obtaining a conductive wire core composed of a conductor and an insulating layer.

[0115] (3) Using a Φ120 extruder, the temperatures of the first to seventh temperature zones of the extruder are set as follows: 130℃, 140℃, 150℃, 160℃, 165℃, 170℃, and 170℃ respectively; the temperatures of the three temperature zones of the die head are set as follows: 170℃, 175℃, and 175℃ respectively. The material of the sheath layer is extruded onto the surface of the insulation layer to obtain the sheath layer.

[0116] (4) Wrap nylon wrapping tape around the surface of the sheath layer to obtain a nylon wrapping layer;

[0117] (5) Using a Φ120 extruder, the temperatures of the first to seventh temperature zones of the extruder are set as follows: 130℃, 140℃, 150℃, 160℃, 165℃, 170℃, and 170℃ respectively; the temperatures of the three temperature zones of the die head are set as follows: 170℃, 175℃, and 175℃ respectively. The material of the sacrificial layer is extruded onto the surface of the nylon wrapping layer to obtain the sacrificial layer, which is the rodent-proof cable.

[0118] Example 2

[0119] This embodiment provides a rodent-proof cable, the structural schematic diagram of which is shown below. Figure 2 As shown, the cable consists of a cable core and a sheath layer 5, a nylon wrapping layer 6, and a sacrificial layer 7 sequentially covering the surface of the cable core. The cable core comprises four conductive wires, a filler layer 3 filling the gaps between the conductive wires, and a non-woven fabric wrapping layer 4 covering the conductive wires and the filler layer. The conductive wires consist of a conductor 1 and an insulating layer 2 covering the surface of the conductor 1. The conductor is a copper conductor with a weighing cross-sectional area of ​​300.4 mm². 2The outer diameter is 23.4 mm, and the DC resistance of the conductor at 20℃ is 0.0635 Ω / km; the insulation layer is made of 110℃ irradiated cross-linked elastomer insulation material (Jiangsu Shangshang Cable Group Co., Ltd. FPJ-110(L405)), and the nominal thickness of the insulation layer is 1.8 mm; the filler layer is made of 110℃ irradiated polypropylene mesh tear-resistant fiber filler rope (Jintan Jinlu- PP rope (temperature resistant 110℃); the non-woven fabric wrapping layer is made of reinforced non-woven fabric (Liyang Huasu-reinforced non-woven fabric), with specifications of 0.16mm (thickness) × 65mm (width) and a wrapping overlap width of 6.5mm; the sheath layer is made of temperature resistant 110℃ UV resistant thermoplastic low smoke halogen-free flame retardant polyolefin (Fangzhide HFS-110-TP), with a nominal thickness of 2.8mm; the nylon wrapping layer is made of nylon wrapping tape with a width of 50mm provided in Preparation Example 1, with a thickness of 0.2mm and an overlap rate of 10%; the sacrificial layer is made of temperature resistant 110℃ UV resistant thermoplastic low smoke halogen-free flame retardant polyolefin (Fangzhide HFS-110-TP), with a nominal thickness of 1.8mm.

[0120] This embodiment provides a method for preparing the rodent-proof cable, specifically including the following steps:

[0121] (1) A copper rod with a diameter of Φ8mm is drawn into a copper monofilament with a diameter of 0.293mm. The elongation of the copper monofilament is 35%, and the resistivity of the copper monofilament is 0.017100Ω•mm. 2 / m; 67 copper monofilaments are bundled together into strands using a bundling machine, with the bundling direction to the left and the outer diameter of the strands being approximately 2.6mm; 61 strands are twisted together into a conductor using a cage stranding machine, arranged in a 1+6+12+18+24 pattern, with the twisting direction to the left, and the outermost layer of the conductor has a twist pitch ratio controlled at 15 times, thus obtaining the conductor;

[0122] (2) Using an 80 extruder, the temperatures of the first to eighth temperature zones of the extruder are set as follows: 120℃, 130℃, 141℃, 154℃, 162℃, 165℃, 165℃, and 165℃ respectively; the temperatures of the three temperature zones of the die head are 175℃, 175℃, and 170℃ respectively. The insulating material is extruded and coated (extruded) onto the surface of the conductor. Then, irradiation is carried out under the conditions of 2.1MeV energy, 14 passes, 25mA beam current, and 10m / min linear speed. After irradiation, a thermal elongation test is carried out. The maximum elongation under load is detected to be 60%, and the maximum permanent elongation after cooling is 0%, thus obtaining a conductive wire core composed of a conductor and an insulating layer.

[0123] (3) The four conductive cores and the filling layer material are cabled together in the right direction and the cable is formed by untwisting. The cable pitch ratio is 20-25. Then, the conductive cores and the filling layer are covered with reinforced non-woven fabric to obtain the cable core.

[0124] (4) Using a Φ150 extruder, the temperatures of the first to eighth temperature zones of the extruder are set as follows: 130℃, 140℃, 150℃, 160℃, 165℃, 170℃, 170℃, 170℃; the temperatures of the three temperature zones of the die head are as follows: 170℃, 175℃, 175℃. The material of the sheath layer is extruded onto the surface of the cable core to obtain the sheath layer.

[0125] (5) Wrap nylon wrapping tape around the surface of the sheath layer to obtain a nylon wrapping layer;

[0126] (6) Using a Φ150 extruder, the temperatures of the first to eighth temperature zones of the extruder are set as follows: 130℃, 140℃, 150℃, 160℃, 165℃, 170℃, 170℃, and 170℃ respectively; the temperatures of the three temperature zones of the die head are 170℃, 175℃, and 175℃ respectively. The material of the sacrificial layer is extruded onto the surface of the nylon wrapping layer to obtain the sacrificial layer, which is the rodent-proof cable.

[0127] Examples 3-10

[0128] Examples 3-10 provide a rodent-proof cable, which differs from Example 1 in that the nylon wrapping layer uses a nylon wrapping tape with a width of 30mm as provided in Examples 2-9. Other materials, structures and process parameters are the same as in Example 1.

[0129] Comparative Example 1

[0130] This comparative example provides a rodent-proof cable, which differs from Example 1 in that the nylon wrapping layer uses a 30mm wide nylon wrapping tape provided in Comparative Preparation Example 1. Other materials, structures, and process parameters are the same as in Example 1.

[0131] Comparative Example 2

[0132] This comparative example provides a rodent-proof cable, which differs from Example 1 in that the nylon wrapping layer uses a nylon wrapping tape with a width of 30mm provided in Comparative Preparation Example 2. Other materials, structures, and process parameters are the same as in Example 1.

[0133] Comparative Example 3

[0134] This comparative example provides a rodent-proof cable, which differs from Example 1 in that the nylon wrapping layer is replaced with a nylon extrusion layer. Specifically, in the preparation method, nylon 12 is extruded onto the surface of the sheath layer. The specific extrusion process is as follows: a 45mm co-rotating twin-screw extruder 9 (length-to-diameter ratio L / D=40:1) is used for melt extrusion. The temperature of the first zone of the twin-screw extruder is set to 185℃, the temperature of the second zone is set to 215℃, and the temperature of the third zone is set to 245℃. The die head pressure is controlled at 12Mpa-15Mpa. Other materials, structures, and process parameters are the same as in Example 1.

[0135] Performance testing

[0136] The following performance tests were performed on the rodent-proof cables provided in the embodiments and comparative examples.

[0137] (1) Bending performance

[0138] Test conditions: The sample should be wound once around a test cylinder at ambient temperature. The diameter of the cylinder is 7D(1±5)%, where D is the outer diameter of the cable. Then, the cable is unwound and the process is repeated in the opposite direction. This operation is repeated 3 times. Then, the sample wound around the test cylinder is placed in an air oven at the highest conductor temperature (90°C) during normal cable operation and heated for 24 hours.

[0139] Test results: When the curved section is cut open, the sheath, nylon wrapping, and sacrificial layer should be free of defects such as deformation, cracks, wrinkles, and splits.

[0140] (2) Rodent and ant repellency

[0141] According to the standard GB / T 34016-2017, the cable can reach the FSY11 level.

[0142] FSY11 grade: The surface of the protective layer of the sample should be free of rat bite marks or visible gnawing marks, the depth of which should be less than 1 mm, and there should be no signs of termite infestation on the surface.

[0143] FSY21 grade: The surface of the protective layer of the sample has rat bite marks greater than 1 mm, but the value should not be greater than 1 / 2 of the thickness of the outer protective layer; and the surface should not show any signs of termite infestation.

[0144] The specific test results are shown in Table 2.

[0145] Table 2

[0146]

[0147] As shown in Table 2, the rodent-proof cable provided in this application, through the nylon wrapping layer formed by setting a specific nylon wrapping tape on the surface of the sheath layer, not only prevents rodents and ants but also has excellent bending performance. It can effectively reduce the outer diameter of the product, reduce the weight of the product, and reduce costs. It does not require the addition of chemical repellents such as capsaicin, making it friendly to the health of operators during cable production and installation, and will not cause pollution to the surrounding environment. As shown in Examples 1-4, after the bending test, the rodent-proof cable provided in this application should have no defects such as deformation, cracks, wrinkles, or cracks in the sheath layer, nylon wrapping layer, and sacrificial layer. It has good bending resistance and the rodent-proof level reaches FSY11.

[0148] As can be seen from Example 1 and Comparative Examples 1-3, the nylon wrapping tape not prepared using a specific process, or the extruded nylon layer, results in cables with poor bending resistance.

[0149] The applicant declares that the above description is only a specific implementation of this application, but the protection scope of this application is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application fall within the protection and disclosure scope of this application.

Claims

1. A rodent- and ant-proof cable, characterized in that, The rodent-proof cable includes a cable core and a sheath layer, a nylon wrapping layer, and a sacrificial layer sequentially wrapped around the surface of the cable core. The cable core includes at least one conductive wire core; The conductive core includes a conductor and an insulating layer covering the surface of the conductor; The nylon wrapping layer is formed by wrapping nylon wrapping tape around the surface of the sheath layer; The nylon wrapping tape is prepared by the following method, which includes: melting and extruding nylon and then gradient calendering to obtain the nylon wrapping tape; The gradient calendering includes a first stage, a second stage, and a third stage performed sequentially; the calendering temperature of the first stage is greater than the calendering temperature of the third stage, which is greater than the calendering temperature of the second stage.

2. The rodent-proof cable according to claim 1, characterized in that, The material of the nylon wrapping tape includes at least one of nylon 12, nylon 6, nylon 11, nylon 1010, nylon 610, and nylon 612; The width of the nylon wrapping tape is 20~50mm; The surface tension of the nylon wrapping tape is 38~42 dyn / cm; The tensile strength of the nylon tape is 55~65MPa, and the elongation at break is 300~400%.

3. The rodent-proof cable according to claim 1, characterized in that, The thickness of the nylon wrapping layer is 0.2~0.3mm; The overlap ratio of the nylon wrapping layer is 5-50%.

4. The rodent-proof cable according to claim 1, characterized in that, The rolling temperature of the first stage is 85~95℃, the rolling temperature of the second stage is 10~15℃, and the rolling temperature of the third stage is 45~55℃. The gas pressure during the first stage of calendering is 0.3~0.5MPa; The rolling speed in the first stage > the rolling speed in the second stage > the rolling speed in the third stage; The rolling speed in the first stage is 7.5~9.5 m / min, the rolling speed in the second stage is 7~9 m / min, and the rolling speed in the third stage is 6.5~8.8 m / min; The rolling speed in the first stage is 0.9 to 1.2, the rolling speed in the second stage is 0.87 to 1.13, and the rolling speed in the third stage is 0.85 to 1.

1.

5. The rodent-proof cable according to claim 1, characterized in that, The nylon has a water content of 0.02~0.04 wt%; The temperature of the melt extrusion is 180~260℃, and the rotation speed is 120~150rpm; The gradient rolling process also includes a corona treatment step; The voltage of the corona treatment is 10~15kV and the frequency is 10~30kHz.

6. The rodent-proof cable according to claim 1, characterized in that, The conductor includes any one of Class I, Class II, Class V, or Class VI conductors; The nominal thickness of the insulating layer is 0.7~3.0 mm; The material of the insulating layer includes at least one of cross-linked polyolefin or cross-linked elastomer; The nominal thickness of the sheath layer is 1.8~3.5mm; The nominal thickness of the sacrificial layer is 1.2~2.5mm; The materials of the sheath layer and the sacrificial layer each independently include low-smoke halogen-free polyolefins; The cable core also includes a filler layer and a second wrapping layer covering the surface of the conductive core and the filler layer; The filling layer is made of polypropylene mesh tear-off fibers; The material of the second wrapping layer includes nonwoven fabric; The overlap ratio of the second wrapping layer is 5-20%.

7. A method for preparing a rodent- and ant-proof cable according to any one of claims 1 to 6, characterized in that, The preparation method includes the following steps: A sheath layer, a nylon wrapping layer, and a sacrificial layer are sequentially disposed on the surface of the cable core to obtain the rodent-proof cable.

8. The method for preparing the rodent- and ant-proof cable according to claim 7, characterized in that, The method for preparing the conductive wire core includes: extruding the insulating layer material onto the surface of the conductor and irradiating it to obtain the conductive wire core; The extrusion temperature is 120~170℃; The irradiation energy is 1~4MeV, the number of channels is 10~20, the beam current is 20~30mA, and the linear velocity is 5~15m / min.

9. The method for preparing the rodent- and ant-proof cable according to claim 7, characterized in that, The preparation method includes: The material of the sheath layer is extruded and wrapped around the surface of the cable core to obtain the sheath layer; nylon wrapping tape is wrapped around the surface of the sheath layer to obtain the nylon wrapping layer; the material of the sacrificial layer is extruded and wrapped around the surface of the nylon wrapping layer to obtain the rodent-proof cable.

10. The application of a rodent-proof cable according to any one of claims 1 to 6 in power, communication, and rail transportation.

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