A method for manufacturing an inner screen embedded crosslinked cable

Abstract

The application relates to a preparation method of an inner-screen-embedding-preventing crosslinked cable, and belongs to the technical field of medium-voltage crosslinked cable manufacturing. The application provides a preparation method of an inner-screen-embedding-preventing crosslinked cable. The crosslinked cable obtained by the preparation method comprises a conductor, and a conductor shielding layer, an insulation layer, an insulation shielding layer, a metal shielding layer, a filler, a wrapping tape, an isolation sleeve, an armor and an outer sheath which are arranged in layers from the inside to the outside of the conductor. The application provides a lubricating master batch for preparing the conductor shielding layer, which comprises SEBS, POE, SEBS-maleic anhydride grafting and modified talcum powder and the like components. The finally prepared lubricating master batch is softened but not completely melted at high temperature, temporarily fills the micro gaps of the conductor, is shrunk and separated after cooling, permanent embedding is avoided, and the service life of the cable is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of medium-voltage cross-linked cable manufacturing technology, and relates to a method for preparing an anti-internal shield embedded cross-linked cable. Background Technology

[0002] Medium-voltage cross-linked cables are widely used in power systems due to their excellent electrical and mechanical properties. According to the GB / T12706.2-2020 standard and the technical specifications of the Southern Power Grid, qualified medium-voltage cross-linked cables should have conductor shielding and insulation shielding both inside and outside the insulation. However, in actual production, when using a three-layer co-extrusion method to produce the insulated core, the problem of conductor shield embedding often occurs. This means that some shielding material is squeezed into the conductor gaps, forming protrusions. In severe cases, this leads to direct contact between the conductor and the insulation material, reducing the electric field insulation withstand voltage level and affecting the cable's service life. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing an anti-internal shield embedded cross-linked cable, the resulting cross-linked cable having a long service life.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A method for preparing an anti-internal shield embedded cross-linked cable, wherein the cross-linked cable obtained by the method comprises a conductor, and a conductor shielding layer, an insulation layer, an insulation shielding layer, a metal shielding layer, a filler, a wrapping tape, a separator, armor, and an outer sheath stacked on the conductor from the inside to the outside.

[0006] Furthermore, the cross-linked cable adopts a composite structure of irregularly shaped stranded conductors. The outer layer of the conductor adopts an arc-shaped trapezoidal structure, while the inner and central layers adopt a circular structure. The irregularly shaped conductor structure is formed by stranding. The outer layer of the conductor is extruded with a conductor shielding layer. During the extrusion of the conductor shielding layer, the nitrogen pressure is 0.8-0.9 MPa. The compaction coefficient of the irregularly shaped conductor is ≥0.96. After stranding the conductor, a 0.05 mm silicone oil layer needs to be coated on the conductor surface. The gap between the outer layer monofilaments is ≤0.05 mm.

[0007] Furthermore, the conductor is 400 mm². 2 The non-circular copper conductor is model TU1; the insulation layer is cross-linked polyethylene, model HFDG-4201; the insulating shielding layer is a semi-conductive outer shielding material, model YPB-10; the metallic shielding layer is copper strip, model TDR; the filler is polypropylene tear film, model PP; the wrapping tape is high-strength non-woven fabric; the isolation sleeve is polyvinyl chloride, model HI-90; the armor is galvanized steel strip, model D-40; and the outer sheath is flame-retardant polyvinyl chloride, model ZAH-90.

[0008] Furthermore, the method for preparing the material of the conductor shielding layer includes the following steps:

[0009] A1. Add ethylene-vinyl acetate copolymer and carbon black to a mixer and mix at 115-125℃ and 30-50rpm for 8-12 minutes. Then add antioxidant 1076, dicumyl peroxide and lubricating masterbatch. Pass through a rolling mill at a roller temperature of 70-90℃, melt extrude, and granulate to obtain semiconductor inner shielding material.

[0010] Further, the mass ratio of the ethylene-vinyl acetate copolymer, carbon black, antioxidant 1076, dicumyl peroxide, and lubricating masterbatch in step A1 is 6.1-6.5:3-3.2:0.8-1:2.6-3:0.6-1.

[0011] Furthermore, the method for preparing the lubricating masterbatch in step A1 includes the following steps:

[0012] B1. Set the initial temperature of the internal mixer to 105-115℃ and the rotation speed to 30-40rpm. Simultaneously add SEBS, POE, and SEBS-maleic anhydride grafts, and mix for 2-4 minutes. Then add white oil and mix for 1-3 minutes. Add antioxidant 1076 and mix for 0.5-1.5 minutes. Add modified talc powder in multiple batches and mix. Melt extrusion and granulation are then performed to obtain lubricating masterbatch.

[0013] Further, the mass ratio of SEBS, POE, SEBS-maleic anhydride graft, white oil, antioxidant 1076, and modified talc in step B1 is 3.6-4:4-4.4:1.1-1.3:0.32-0.36:0.25-0.27:0.08-0.12.

[0014] Furthermore, the preparation method of the modified talc powder in step B1 includes the following steps:

[0015] C1. Preheat talc powder to 78-82℃, spray in γ-aminopropyltriethoxysilane, the mass ratio of talc powder to γ-aminopropyltriethoxysilane is 1:0.24-0.28, mix at 1000-1400 rpm for 16-20 min to obtain modified talc powder.

[0016] Furthermore, the multiple batch addition of modified talc powder in step B1 refers to dividing the modified talc powder into three equal parts and adding it in three batches. When adding the first batch, the mixing temperature is 105-115℃ and the mixing time is 2-4 minutes. When adding the second batch, the mixing temperature is 98-102℃ and the mixing time is 2-4 minutes. When adding the third batch, the mixing temperature is 90-96℃ and the mixing time is 1-2 minutes.

[0017] Furthermore, the thickness of the semiconductor inner shielding material is 0.7-0.9 mm.

[0018] The beneficial effects of this invention are:

[0019] (1) The present invention provides a lubricating masterbatch, which uses SEBS to construct an elastic skeleton, POE linear molecular chains to improve fluidity, and SEBS-maleic anhydride grafts to improve interfacial adhesion with shielding materials such as ethylene-vinyl acetate copolymers. Based on this, modified talc is introduced to improve the compatibility between talc and non-polar groups. At the same time, multiple batches are added to avoid agglomeration. The lubricating masterbatch obtained by this compound can be uniformly dispersed in the shielding material, so that the lubricating masterbatch softens but does not completely melt at high temperature, temporarily fills the micro gaps in the conductor, shrinks and detaches after cooling, avoids permanent embedding, and thus extends the service life of the cable.

[0020] (2) The present invention provides a specific conductor structure, which forms a double barrier through a composite structure of a circular compacted inner layer and a shaped monofilament outer layer, as well as a silicone oil coating, effectively reducing gaps and lowering the risk of shielding material embedding. Nitrogen gas is used for protection during the extrusion process to prevent conductor oxidation, improve surface quality, improve the uniformity of electric field distribution, and thus improve the performance of the cable. Attached Figure Description

[0021] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the cross-linked cable of the present invention;

[0023] Among them, 1-conductor, 2-conductor shielding layer, 3-insulating layer, 4-insulating shielding layer, 5-metallic shielding layer, 6-filler, 7-wrapping tape, 8-isolation sleeve, 9-armor, 10-outer sheath. Detailed Implementation

[0024] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0025] The 400mm in all embodiments and comparative examples of this invention 2The use of irregularly shaped copper conductors conforms to standard GB / T 3956-2008; the use of conductor shielding layer, insulation layer, insulating shielding layer, metallic shielding layer, filler, wrapping tape, isolation sleeve, armor and outer sheath all conform to standard GB / T 12706.2-2020; the CAS number of the carbon black is 1333-86-4; the type of SEBS is YH-602; the type of POE is ENGAGE 8180; the type of SEBS-maleic anhydride graft is KRATON; the type of white oil is PS-32; the particle size of the talc is 800 mesh.

[0026] Cross-linked cables

[0027] Please refer to Figure 1 The cross-linked cable of this embodiment includes a conductor 1, and a conductor shielding layer 2, an insulation layer 3, an insulation shielding layer 4, a metal shielding layer 5, a filler 6, a wrapping tape 7, a separator 8, an armor 9, and an outer sheath 10 stacked on the conductor 1 from the inside to the outside.

[0028] The cross-linked cable adopts a composite structure of irregularly shaped stranded conductors. The outer layer of the conductor adopts an arc trapezoidal structure, while the inner and central layers adopt a circular structure. The irregularly shaped conductor structure is formed by stranding. The outer layer of the conductor is extruded with a conductor shielding layer. During the extrusion of the conductor shielding layer, the nitrogen pressure is 0.85 MPa. The compaction coefficient of the irregularly shaped conductor is 0.96. After stranding the conductor, a 0.05 mm silicone oil layer needs to be coated on the conductor surface. The gap between the outer layer monofilaments is 0.05 mm.

[0029] The conductor is a 400mm² irregularly shaped copper conductor, model TU1; the insulation layer is cross-linked polyethylene, model HFDG-4201; the insulating shielding layer is a semi-conductive outer shielding material, model YPB-10; the metal shielding layer is copper tape, model TDR; the filler is polypropylene tear film, model PP; the wrapping tape is high-strength non-woven fabric; the isolation sleeve is polyvinyl chloride, model HI-90; the armor is galvanized steel tape, model D-40; the outer sheath is flame-retardant polyvinyl chloride, model ZAH-90.

[0030] [Methods for preparing conductor shielding layers]

[0031] Example 1

[0032] The method for preparing the conductor shielding layer material of the cross-linked cable in this embodiment includes the following steps:

[0033] A1. Add ethylene-vinyl acetate copolymer and carbon black to a mixer and mix at 115°C and 30 rpm for 8 minutes. Then add antioxidant 1076, dicumyl peroxide and lubricating masterbatch. Pass through a thin mill at a roller temperature of 70°C, melt extrude, and granulate to obtain semiconductor inner shielding material.

[0034] The mass ratio of the ethylene-vinyl acetate copolymer, carbon black, antioxidant 1076, dicumyl peroxide, and lubricating masterbatch in step A1 is 6.1:3:0.8:2.6:0.6.

[0035] The method for preparing the lubricating masterbatch in step A1 includes the following steps:

[0036] B1. Set the initial temperature of the internal mixer to 105℃ and the rotation speed to 30rpm. Simultaneously add SEBS, POE, and SEBS-maleic anhydride grafts, and mix for 2 minutes. Then add white oil and mix for 1 minute. Add antioxidant 1076 and mix for 0.5 minutes. Add modified talc powder in multiple batches and mix. Melt extrusion and granulation are performed to obtain lubricating masterbatch.

[0037] The mass ratio of SEBS, POE, SEBS-maleic anhydride graft, white oil, antioxidant 1076, and modified talc in step B1 is 3.6:4:1.1:0.32:0.25:0.08.

[0038] The preparation method of the modified talc powder described in step B1 includes the following steps:

[0039] C1. Preheat talc powder to 78°C, and spray in γ-aminopropyltriethoxysilane. The mass ratio of talc powder to γ-aminopropyltriethoxysilane is 1:0.24. Mix at 1000 rpm for 16 min to obtain modified talc powder.

[0040] The multiple batch addition of modified talc powder in step B1 refers to dividing the modified talc powder into three equal parts and adding it in three batches. The mixing temperature for the first batch is 105℃ and the mixing time is 2 minutes. The mixing temperature for the second batch is 98℃ and the mixing time is 2 minutes. The mixing temperature for the third batch is 90℃ and the mixing time is 1 minute.

[0041] The thickness of the semiconductor inner shielding material is 0.7 mm.

[0042] Example 2

[0043] The method for preparing the conductor shielding layer material of the cross-linked cable in this embodiment includes the following steps:

[0044] A1. Add ethylene-vinyl acetate copolymer and carbon black to a mixer and mix at 115°C and 30 rpm for 9 minutes. Then add antioxidant 1076, dicumyl peroxide and lubricating masterbatch. Pass through a thin mill at a roller temperature of 75°C, melt extrude, and granulate to obtain semiconductor inner shielding material.

[0045] The mass ratio of ethylene-vinyl acetate copolymer, carbon black, antioxidant 1076, dicumyl peroxide, and lubricating masterbatch in step A1 is 6.2:3.08:0.86:2.7:0.7.

[0046] The method for preparing the lubricating masterbatch in step A1 includes the following steps:

[0047] B1. Set the initial temperature of the internal mixer to 105℃ and the rotation speed to 30rpm. Simultaneously add SEBS, POE, and SEBS-maleic anhydride grafts, and mix for 2 minutes. Then add white oil and mix for 1 minute. Add antioxidant 1076 and mix for 0.5 minutes. Add modified talc powder in multiple batches and mix. Melt extrusion and granulation are performed to obtain lubricating masterbatch.

[0048] The mass ratio of SEBS, POE, SEBS-maleic anhydride graft, white oil, antioxidant 1076, and modified talc in step B1 is 3.7:4.1:1.15:0.33:0.25:0.09.

[0049] The preparation method of the modified talc powder described in step B1 includes the following steps:

[0050] C1. Preheat talc powder to 79°C, and spray in γ-aminopropyltriethoxysilane. The mass ratio of talc powder to γ-aminopropyltriethoxysilane is 1:0.25. Mix at 1100 rpm for 17 min to obtain modified talc powder.

[0051] The multiple batch addition of modified talc powder in step B1 refers to dividing the modified talc powder into three equal parts and adding it in three batches. When adding the first batch, the mixing temperature is 105℃ and the mixing time is 2 minutes. When adding the second batch, the mixing temperature is 99℃ and the mixing time is 2 minutes. When adding the third batch, the mixing temperature is 92℃ and the mixing time is 1 minute.

[0052] The thickness of the semiconductor inner shielding material is 0.7 mm.

[0053] Example 3

[0054] The method for preparing the conductor shielding layer material of the cross-linked cable in this embodiment includes the following steps:

[0055] A1. Add ethylene-vinyl acetate copolymer and carbon black to a mixer and mix at 120°C and 40 rpm for 10 min. Then add antioxidant 1076, dicumyl peroxide and lubricating masterbatch. Pass through a thin mill at a roller temperature of 80°C, melt extrude, and granulate to obtain semiconductor inner shielding material.

[0056] The mass ratio of the ethylene-vinyl acetate copolymer, carbon black, antioxidant 1076, dicumyl peroxide, and lubricating masterbatch in step A1 is 6.3:3.1:0.9:2.8:0.8.

[0057] The method for preparing the lubricating masterbatch in step A1 includes the following steps:

[0058] B1. Set the initial temperature of the internal mixer to 110℃ and the rotation speed to 35rpm. Simultaneously add SEBS, POE, and SEBS-maleic anhydride grafts, mix for 3 minutes, then add white oil and mix for 2 minutes. Add antioxidant 1076 and mix for 1 minute. Add modified talc powder in multiple batches and mix. Melt extrusion, granulation, and obtain lubricating masterbatch.

[0059] The mass ratio of SEBS, POE, SEBS-maleic anhydride graft, white oil, antioxidant 1076, and modified talc in step B1 is 3.8:4.2:1.2:0.34:0.26:0.1.

[0060] The preparation method of the modified talc powder described in step B1 includes the following steps:

[0061] C1. Preheat talc powder to 80°C, and spray in γ-aminopropyltriethoxysilane. The mass ratio of talc powder to γ-aminopropyltriethoxysilane is 1:0.26. Mix at 1200 rpm for 18 min to obtain modified talc powder.

[0062] The multiple batch addition of modified talc powder in step B1 refers to dividing the modified talc powder into three equal parts and adding it in three batches. When adding the first batch, the mixing temperature is 110℃ and the mixing time is 3 minutes. When adding the second batch, the mixing temperature is 100℃ and the mixing time is 3 minutes. When adding the third batch, the mixing temperature is 93℃ and the mixing time is 1.5 minutes.

[0063] The thickness of the semiconductor internal shielding material is 0.8 mm.

[0064] Example 4

[0065] The method for preparing the conductor shielding layer material of the cross-linked cable in this embodiment includes the following steps:

[0066] A1. Add ethylene-vinyl acetate copolymer and carbon black to a mixer and mix at 125°C and 50 rpm for 11 min. Then add antioxidant 1076, dicumyl peroxide and lubricating masterbatch. Pass through a thin mill at a roller temperature of 85°C, melt extrude, and granulate to obtain semiconductor inner shielding material.

[0067] The mass ratio of ethylene-vinyl acetate copolymer, carbon black, antioxidant 1076, dicumyl peroxide, and lubricating masterbatch in step A1 is 6.4:3.13:0.95:2.9:0.9.

[0068] The method for preparing the lubricating masterbatch in step A1 includes the following steps:

[0069] B1. Set the initial temperature of the internal mixer to 115℃ and the rotation speed to 40rpm. Simultaneously add SEBS, POE, and SEBS-maleic anhydride grafts, and mix for 4 minutes. Then add white oil and mix for 3 minutes. Add antioxidant 1076 and mix for 1.5 minutes. Add modified talc powder in multiple batches and mix. Melt extrusion, granulation, and obtain lubricating masterbatch.

[0070] The mass ratio of SEBS, POE, SEBS-maleic anhydride graft, white oil, antioxidant 1076, and modified talc in step B1 is 3.9:4.3:1.24:0.35:0.27:0.11.

[0071] The preparation method of the modified talc powder described in step B1 includes the following steps:

[0072] C1. Preheat talc powder to 81°C, and spray in γ-aminopropyltriethoxysilane. The mass ratio of talc powder to γ-aminopropyltriethoxysilane is 1:0.27. Mix at 1300 rpm for 19 min to obtain modified talc powder.

[0073] The multiple batch addition of modified talc powder in step B1 refers to dividing the modified talc powder into three equal parts and adding it in three batches. The mixing temperature for the first batch is 115℃ and the mixing time is 4 minutes. The mixing temperature for the second batch is 101℃ and the mixing time is 4 minutes. The mixing temperature for the third batch is 95℃ and the mixing time is 2 minutes.

[0074] The thickness of the semiconductor inner shielding material is 0.9 mm.

[0075] Example 5

[0076] The method for preparing the conductor shielding layer material of the cross-linked cable in this embodiment includes the following steps:

[0077] A1. Add ethylene-vinyl acetate copolymer and carbon black to a mixer and mix at 125°C and 50 rpm for 12 min. Then add antioxidant 1076, dicumyl peroxide and lubricating masterbatch. Pass through a thin mill at a roller temperature of 90°C, melt extrude, and granulate to obtain semiconductor inner shielding material.

[0078] The mass ratio of the ethylene-vinyl acetate copolymer, carbon black, antioxidant 1076, dicumyl peroxide, and lubricating masterbatch in step A1 is 6.5:3.2:1:3:1.

[0079] The method for preparing the lubricating masterbatch in step A1 includes the following steps:

[0080] B1. Set the initial temperature of the internal mixer to 115℃ and the rotation speed to 40rpm. Simultaneously add SEBS, POE, and SEBS-maleic anhydride grafts, and mix for 4 minutes. Then add white oil and mix for 3 minutes. Add antioxidant 1076 and mix for 1.5 minutes. Add modified talc powder in multiple batches and mix. Melt extrusion, granulation, and obtain lubricating masterbatch.

[0081] The mass ratio of SEBS, POE, SEBS-maleic anhydride graft, white oil, antioxidant 1076, and modified talc in step B1 is 4:4.4:1.3:0.36:0.27:0.12.

[0082] The preparation method of the modified talc powder described in step B1 includes the following steps:

[0083] C1. Preheat talc powder to 82°C, and spray in γ-aminopropyltriethoxysilane. The mass ratio of talc powder to γ-aminopropyltriethoxysilane is 1:0.28. Mix at 1400 rpm for 20 min to obtain modified talc powder.

[0084] The multiple batch addition of modified talc powder in step B1 refers to dividing the modified talc powder into three equal parts and adding it in three batches. The mixing temperature for the first batch is 115℃ and the mixing time is 4 minutes. The mixing temperature for the second batch is 102℃ and the mixing time is 4 minutes. The mixing temperature for the third batch is 96℃ and the mixing time is 2 minutes.

[0085] The thickness of the semiconductor inner shielding material is 0.9 mm.

[0086] Example 6

[0087] Based on Example 3, the lubricating masterbatch in the conductor shielding layer was removed and replaced with an equal weight of silicone masterbatch, which was purchased from Guangdong Fantian Technology Co., Ltd., model FT-333. Other conditions remained the same as in Example 3.

[0088] Example 7

[0089] Based on Example 3, POE in the lubricant masterbatch preparation process was removed and replaced with an equal weight of SEBS, while other conditions remained the same as in Example 3.

[0090] Example 8

[0091] Based on Example 3, the SEBS-maleic anhydride graft material in the lubricant masterbatch preparation process was removed and replaced with an equal weight of SEBS, while other conditions remained the same as in Example 3.

[0092] Example 9

[0093] Based on Example 3, the modified talc powder was removed and replaced with an equal weight of talc powder with a particle size of 800 mesh, and other conditions remained the same as in Example 3.

[0094] Comparative Example 1

[0095] Based on Example 3, while keeping other conditions consistent, the preparation method of the lubricating masterbatch was changed to the following steps:

[0096] B1. Set the initial temperature of the internal mixer to 110℃ and the rotation speed to 35rpm. Simultaneously add SEBS, POE, and SEBS-maleic anhydride grafts, and mix for 3 minutes. Then add white oil and mix for 2 minutes. Add antioxidant 1076 and mix for 1 minute. Keep the temperature constant, add modified talc powder and mix for 7.5 minutes. Melt extrusion and granulation are performed to obtain lubricating masterbatch.

[0097] Comparative Example 2

[0098] Based on Example 3, while keeping other conditions consistent, the preparation method of the lubricating masterbatch was changed to the following steps:

[0099] B1. Set the initial temperature of the internal mixer to 110℃ and the rotation speed to 35rpm. Simultaneously add SEBS, POE, and SEBS-maleic anhydride grafts, and mix for 3 minutes. Then add white oil and mix for 2 minutes. Add antioxidant 1076 and mix for 1 minute. Cool down to 93℃, add modified talc powder and mix for 7.5 minutes. Melt extrusion and granulation are performed to obtain lubricating masterbatch.

[0100] Comparative Example 3

[0101] Based on Example 3, while keeping other conditions consistent, the preparation method of the lubricating masterbatch was changed to the following steps:

[0102] B1. Set the initial temperature of the internal mixer to 110℃ and the rotation speed to 35rpm. Simultaneously add SEBS, POE, and SEBS-maleic anhydride grafts, and mix for 3 minutes. Then add white oil and mix for 2 minutes. Add antioxidant 1076 and mix for 1 minute. Divide the modified talc powder into two equal parts and add it in two batches. When adding the first batch, the mixing temperature is 100℃ and the mixing time is 6 minutes. When adding the second batch, the temperature is 93℃ and the mixing time is 1.5 minutes. Melt extrusion and granulation are performed to obtain lubricating masterbatch.

[0103] Comparative Example 4

[0104] Based on Example 3, while keeping other conditions consistent, the preparation method of the lubricating masterbatch was changed to the following steps:

[0105] B1. Set the initial temperature of the internal mixer to 110℃ and the rotation speed to 35rpm. Simultaneously add SEBS, POE, SEBS-maleic anhydride graft, white oil, antioxidant 1076, and modified talc powder. Mix for 13.5min, melt extrude, and granulate to obtain lubricating masterbatch.

[0106] Using the cross-linked cables prepared in Examples 1-9 and Comparative Examples 1-4 as samples, the test tool was pressed onto the sample with the specified force, and the sample was placed in an air oven at 130°C for 6 hours. After the time was up, the sample was cooled, and the percentage of the indentation depth to the cable diameter was measured and recorded as shown in Table 1 below.

[0107]

[0108] As shown in Table 1, the cross-linked cable prepared in the embodiments of the present invention exhibits less indentation during the high-temperature pressure test, which can effectively prevent the inner screen from embedding and thus affecting the cable's service life.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any indirect modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing an anti-internal shield embedded cross-linked cable, characterized in that: Includes the following steps: (1) Preparation of irregular stranded conductor: The outer layer of the conductor adopts a circular arc trapezoidal structure, and the inner and central layers adopt a circular structure. The irregular conductor structure is formed by stranding. The compaction coefficient of the irregular conductor is controlled to be ≥0.96, and the gap between the outer single wires is ≤0.05mm. After stranding, a 0.05mm silicone oil layer is coated on the surface of the conductor. (2) Materials for preparing the conductor shielding layer:

21. Preparation of modified talc: Preheat talc to 78-82℃, spray in γ-aminopropyltriethoxysilane, the mass ratio of talc to γ-aminopropyltriethoxysilane is 1:0.24-0.28, mix at 1000-1400 rpm for 16-20 min to obtain modified talc; 22. Preparation of lubricating masterbatch: Set the initial temperature of the internal mixer to 105-115℃ and the rotation speed to 30-40rpm. Simultaneously add SEBS, POE, and SEBS-maleic anhydride grafts, and mix for 2-4 minutes. Then add white oil and mix for 1-3 minutes. Add antioxidant 1076 and mix for 0.5-1.5 minutes. Add modified talc powder in multiple batches and mix. Melt extrusion and granulation are then performed to obtain lubricating masterbatch.

23. Preparation of semiconductor inner shielding material: Add ethylene-vinyl acetate copolymer and carbon black to a mixer and mix at 115-125℃ and 30-50rpm for 8-12min. Then add antioxidant 1076, dicumyl peroxide and lubricating masterbatch. Pass through a rolling mill at a roller temperature of 70-90℃, melt extrude, and granulate to obtain semiconductor inner shielding material. (3) Extrusion of conductor shielding layer: Under nitrogen pressure of 0.8-0.9 MPa, the material of conductor shielding layer obtained in step (2) is extruded on the outer layer of conductor to form conductor shielding layer; (4) Subsequent processing: The conductor shielding layer is stacked from the inside to the outside with an insulating layer, an insulating shielding layer, a metal shielding layer, a filler, a wrapping tape, an isolation sleeve, armor and an outer sheath to obtain the final product.

2. The method for preparing an anti-internal shield embedded cross-linked cable according to claim 1, characterized in that: The conductor is 400mm. 2 Special-shaped copper conductor, model TU1; The insulating layer is cross-linked polyethylene, model HFDG-4201; the insulating shielding layer is a semi-conductive outer shielding material, model YPB-10; the metal shielding layer is copper tape, model TDR; the filler is polypropylene tear film, model PP; the wrapping tape is high-strength non-woven fabric; the isolation sleeve is polyvinyl chloride, model HI-90; the armor is galvanized steel tape, model D-40; and the outer sheath is flame-retardant polyvinyl chloride, model ZAH-90.

3. The method for preparing an anti-internal shield embedded cross-linked cable according to claim 1, characterized in that: The mass ratio of ethylene-vinyl acetate copolymer, carbon black, antioxidant 1076, dicumyl peroxide, and lubricating masterbatch in step 23 is 6.1-6.5:3-3.2:0.8-1:2.6-3:0.6-1.

4. The method for preparing an anti-internal shield embedded cross-linked cable according to claim 1, characterized in that: The mass ratio of SEBS, POE, SEBS-maleic anhydride graft, white oil, antioxidant 1076, and modified talc in step 22 is 3.6-4:4-4.4:1.1-1.3:0.32-0.36:0.25-0.27:0.08-0.

12.

5. The method for preparing an anti-internal shield embedded cross-linked cable according to claim 1, characterized in that: The multiple batch addition of modified talc powder in step 22 refers to dividing the modified talc powder into three equal parts and adding it in three batches. When adding the first batch, the mixing temperature is 105-115℃ and the mixing time is 2-4 minutes. When adding the second batch, the mixing temperature is 98-102℃ and the mixing time is 2-4 minutes. When adding the third batch, the mixing temperature is 90-96℃ and the mixing time is 1-2 minutes.

6. The method for preparing an anti-internal shield embedded cross-linked cable according to claim 1, characterized in that: The thickness of the semiconductor inner shielding material is 0.7-0.9 mm.

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