Energy-saving filler modified flame-retardant insulated cable

Abstract

The invention belongs to the technical field of cable modification preparation and processing, and particularly relates to an energy-saving filler modified flame-retardant insulated cable, which mainly comprises a conductor wire core, an insulating layer and a sheath layer from inside to outside in a layer structure, and the sheath layer comprises polyolefin, a maleic anhydride grafted polyolefin compatilizer, a crosslinking initiator, an inorganic flame-retardant filler and a processing aid, wherein a silane coupling agent containing carbon-carbon double bonds is grafted and distributed on the inorganic flame-retardant filler, and the particle size of the inorganic flame-retardant filler is 200-400 meshes. Through surface modification of the inorganic flame-retardant filler and introduction of the initiating cross-linking agent, the large-particle inorganic flame-retardant filler is further dispersed and refined in the cable extrusion processing process, so that the grinding and crushing link of the inorganic flame-retardant filler in the early stage is reduced, and the cost and the processing difficulty are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of cable modification, preparation and processing, and particularly relates to an energy-saving filler-modified flame-retardant insulated cable. Background Art

[0002] Wires and cables are widely used in various industries and play a very important role in industrial production and people's lives. However, wires and cables are often used to transmit strong currents, which causes them to heat up. At the same time, the harsh external laying environment also causes the cable materials to age. These factors are the hidden dangers of cable materials (when in contact with ambient air) catching fire. Therefore, flame-retardant cables have become one of the key research directions of cables.

[0003] Aluminum hydroxide and magnesium hydroxide are common flame retardant fillers. When they encounter flames, they decompose to generate water, thereby inhibiting the spread of flames. However, since they are inorganic fillers, they are prone to agglomeration after being added to resin polymers, resulting in deterioration of the physical and mechanical properties of the cable. Therefore, improving the dispersion compatibility of such inorganic fillers in the polymer matrix is ​​particularly important in the processing and preparation of flame retardant cables.

[0004] Among them, the smaller the particle size of the inorganic filler and the larger the specific surface area, the better the affinity between it and the polymer resin, which helps the mechanical properties of the composite material; at the same time, the smaller the particle size of the inorganic flame retardant filler and the larger the specific surface area, the better the flame retardant effect will be. However, in comparison, the price of inorganic fillers with small particle size is often relatively high, and grinding and refining the purchased large particles of inorganic fillers will increase the processing steps, so there is a risk of increasing processing difficulty and cost. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides an energy-saving filler-modified flame-retardant insulated cable, which mainly selects an inorganic flame-retardant filler surface modification additive and introduces an initiator that can cause the polymer resin chain to cross-link. Even if the inorganic flame-retardant filler is blended and added in the form of large particles, it can still be further dispersed and refined during the processing and molding of the cable material, thereby reducing the grinding and crushing steps of the inorganic flame-retardant filler and reducing the cost and processing difficulty.

[0006] Specifically, the cable mainly includes a conductor core, an insulation layer and a sheath layer from the inside to the outside in terms of layer structure, wherein the sheath layer, calculated by weight, includes 100 parts of polyolefin, 10 to 25 parts of maleic anhydride grafted polyolefin compatibilizer, 1 to 2 parts of a cross-linking initiator, 40 to 80 parts of an inorganic flame retardant filler, 4 to 10 parts of a silane coupling agent containing a carbon-carbon double bond, and 10 to 15 parts of a processing aid, wherein the inorganic flame retardant filler is a microspherical aluminum hydroxide or magnesium hydroxide with a particle size of 200 mesh to 400 mesh, and the silane coupling agent containing a carbon-carbon double bond is grafted and distributed on the inorganic flame retardant filler.

[0007] Preferably, the polyolefin comprises one or a combination of polyethylene and polypropylene;

[0008] Preferably, the maleic anhydride grafted polyolefin compatibilizer includes one or a combination of maleic anhydride grafted polyethylene and maleic anhydride grafted polypropylene;

[0009] Preferably, the silane coupling agent containing a carbon-carbon double bond includes one or a combination of two or more of vinyl trimethoxy silane (KH-171), vinyl triethoxy silane (KH-151), methacryloxypropyl trimethoxy silane (KH-570), and vinyl triisopropoxy silane (KH-1706);

[0010] Preferably, the processing aids include plasticizers, antioxidants, lubricants and the like.

[0011] Preferably, the inorganic flame retardant filler is added into a dispersion of a silane coupling agent containing carbon-carbon double bonds (the solvent of the dispersion is ethanol and water mixed in a mass ratio of 9:1) at a solid-liquid ratio of 1:30-100 (g / mL), stirred at 30-60°C for 1-4 hours, and then the inorganic flame retardant filler is separated by centrifugation and dried to obtain an inorganic flame retardant filler grafted with a silane coupling agent containing carbon-carbon double bonds.

[0012] Preferably, the cable has a shielding layer between the insulating layer and the sheath layer in the layer structure.

[0013] Preferably, a plurality of conductor cores with surfaces covered with an insulating layer are uniformly twisted together as a whole, and the sheath layer is covered on the whole.

[0014] Preferably, the processing method of the sheath layer comprises: fully mixing and dispersing polyolefin, maleic anhydride grafted polyolefin compatibilizer, cross-linking initiator, inorganic flame retardant filler grafted with silane coupling agent containing carbon-carbon double bonds, and processing aid, and then blending and melting and extruding granulation through a screw extruder to form a sheath layer masterbatch; then, the sheath layer masterbatch is melted through a screw extruder, and then extruded onto the surface of the insulating layer as the sheath layer.

[0015] The beneficial effects of the present invention are as follows: firstly, as for the single inorganic flame retardant filler particle in the present solution, due to the large particle size, it has a large surface area (not specific surface area), and after the surface treatment with the silane coupling agent, a large number of silane coupling agent molecules can be connected to the surface of the single particle, and these silane coupling agent molecules also have carbon-carbon double bonds; on the other hand, since a cross-linking initiator is added to the polymer resin matrix, during the extrusion process, while cross-linking occurs between the molecular chains of the matrix polymer, the cross-linking initiator will also trigger the opening of the carbon-carbon double bonds on the silane coupling agent, thereby chemically reacting with the macromolecular chains of the matrix polymer to connect together.

[0016] On this basis, due to the strong shear dispersion effect of extrusion processing, obvious relative displacements continuously occur between the macromolecules of the matrix polymer in the molten state (even if local segments of the macromolecules participate in crosslinking). During this process, these macromolecular chains are equivalent to pulling a large inorganic flame retardant filler particle in all directions through a silane coupling agent, and are sufficient to break the internal cohesive forces (such as van der Waals forces and electrostatic forces) inside the filler large particle, causing the filler large particle to disintegrate into more small particles, thereby effectively improving the dispersion of the inorganic filler in the resin matrix, achieving an effect similar to directly using small particle size fillers. Thus, the grinding and pulverization process of the inorganic filler in the early stage is reduced, and the cost and processing procedures are reduced. Brief Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the internal layer structure of the energy-saving filler modified flame-retardant insulated cable of the present invention. Among them, 1 - conductor core, 2 - insulating layer, 3 - shielding layer, 4 - non-woven fabric layer, 5 - filling strip, 6 - sheath layer. Detailed Embodiments

[0018] For the convenience of comparison, the following detailed embodiments are divided into two groups, group A and group B. Group A adopts crosslinking initiation measures during the extrusion process (that is, in line with the design of this solution), and group B does not initiate crosslinking (that is, deviates from the design of this solution). The polypropylene used in the following examples and comparative examples is Yanshan Petrochemical 1396D, maleic anhydride grafted polypropylene is Arkema 18722, crosslinking initiator is diisopropylbenzene peroxide, plasticizer is dioctyl phthalate, antioxidant is 1010, and lubricant is zinc stearate, all of which are commercially available.

[0019] Example 1 of Group A

[0020] 50 parts by weight of microspherical aluminum hydroxide with a particle size of 200 mesh was added to 400 parts by weight of a KH-570 dispersion liquid with a mass concentration of 2% (the solvent of the dispersion liquid is a uniform mixture of ethanol and water in a mass ratio of 9:1). After heating to 45°C under stirring and keeping stirring for 2 hours, the aluminum hydroxide inorganic filler was separated by centrifugation and dried thoroughly at 70°C to obtain an aluminum hydroxide inorganic filler grafted with KH-570.

[0021] 100 parts by weight of polyolefin, 20 parts by weight of maleic anhydride grafted polyolefin compatibilizer, 1 part by weight of crosslinking initiator, the aluminum hydroxide inorganic filler grafted with KH-570 prepared in the above-mentioned example of this embodiment (in total, 52 parts by weight), 10 parts by weight of plasticizer, 2 parts by weight of antioxidant, and 3 parts by weight of lubricant are added to a high-speed disperser and blended at a rotation speed of 900 r / min for 20 min to obtain a blended material. Then, the obtained blended material is melt-extruded and pelletized through a twin-screw extruder at 160°C to 210°C (zone 1: 160°C, zone 2: 175°C, zone 3: 190°C, zone 4: 200°C, zone 5: 210°C, die orifice: 200°C, screw length-diameter ratio: 30:1) to obtain a sheath layer masterbatch.

[0022] The conventional insulation layer masterbatch is melted in an extruder and coaxially and uniformly extruded and coated on the outer surface of a conductor core (formed by uniformly stranding a number of round copper wires, the same hereinafter), and after cooling, an insulation layer coated on the conductor core is formed; an aluminum-plastic composite tape is uniformly and tightly wound around the outer surface of the above-mentioned insulation layer to form a shielding layer coaxially arranged with the insulation layer; 7 conductor cores after the above-mentioned coating treatment and a number of filling strips for filling the gaps between these conductor cores are parallelly aligned and concentrated together (in the radial distribution of these 7 conductor cores: one in the inner side, and six are uniformly and tightly surrounded and arranged in a circular manner on the outer side, the same hereinafter), and then uniformly stranded. Then, these stranded conductor cores and filling strips are taken as a whole, and a non-woven fabric layer is uniformly and tightly wound around them. Then, the sheath layer masterbatch prepared in the above-mentioned example of this embodiment is melted through a twin-screw extruder at 160°C to 200°C (zone 1: 160°C, zone 2: 170°C, zone 3: 185°C, zone 4: 195°C, zone 5: 200°C, die orifice: 195°C, screw length-diameter ratio: 30:1) and coaxially and uniformly extruded and coated on the outer surface of the non-woven fabric layer, and after cooling, a sheath layer is formed (the thickness of the sheath layer is about 2.2 mm, the same hereinafter).

[0023] Example 2 of Group A

[0024] 40 parts by weight of microspherical aluminum hydroxide with a particle size of 300 mesh is added to 500 parts by weight of a 2% KH-151 dispersion liquid (the solvent of the dispersion liquid is uniformly mixed by ethanol and water in a mass ratio of 9:1). Under a stirring state, the temperature is raised to 50°C and kept warm and stirred for 1 hour, and then the aluminum hydroxide inorganic filler is centrifuged and dried sufficiently at 70°C to obtain an aluminum hydroxide inorganic filler grafted with KH-151.

[0025] 100 parts by weight of polyolefin, 18 parts by weight of maleic anhydride grafted polyolefin compatibilizer, 1 part by weight of crosslinking initiator, the aluminum hydroxide inorganic filler grafted with KH-151 prepared in the above-mentioned preparation of this example (all, 41.8 parts by weight), 9 parts by weight of plasticizer, 1 part by weight of antioxidant, and 2 parts by weight of lubricant were added to a high-speed disperser and blended at a rotation speed of 900 r / min for 20 min to obtain a mixture. Then, the obtained mixture was melt-extruded and pelletized through a twin-screw extruder at 160 °C to 210 °C (zone 1: 160 °C, zone 2: 175 °C, zone 3: 190 °C, zone 4: 200 °C, zone 5: 210 °C, die orifice: 200 °C, screw length-diameter ratio: 30:1) to obtain a sheath layer masterbatch.

[0026] The conventional insulation layer masterbatch was melted in an extruder and coaxially and uniformly extruded and wrapped on the outer surface of the conductor core, and after cooling, an insulation layer covering the conductor core was formed; an aluminum-plastic composite tape was uniformly and tightly wound around the above-mentioned insulation layer to form a shielding layer coaxially arranged with the insulation layer; 7 conductor cores after the above-mentioned coating treatment and several filling strips for filling the gaps between these conductor cores were parallelly aligned and concentrated together and then uniformly stranded. Then, these stranded conductor cores and filling strips were taken as a whole, and a non-woven fabric layer was uniformly and tightly wound on them. Then, the sheath layer masterbatch prepared in the above-mentioned preparation of this example was melted through a twin-screw extruder at 160 °C to 200 °C (zone 1: 160 °C, zone 2: 170 °C, zone 3: 185 °C, zone 4: 195 °C, zone 5: 200 °C, die orifice: 195 °C, screw length-diameter ratio: 30:1) and coaxially and uniformly extruded and wrapped on the outer surface of the non-woven fabric layer, and after cooling, a sheath layer was formed.

[0027] Group A Comparative Example 1

[0028] Use "microspherical aluminum hydroxide with a particle size of 1000 mesh" instead of "microspherical aluminum hydroxide with a particle size of 200 mesh", and the other components and operations are the same as those in Example 1 of Group A:

[0029] 50 parts by weight of microspherical aluminum hydroxide with a particle size of 1000 mesh was added to 400 parts by weight of a KH-570 dispersion liquid with a mass concentration of 2% (the solvent of the dispersion liquid was a uniform mixture of ethanol and water in a mass ratio of 9:1). After heating to 45 °C under stirring and maintaining stirring for 2 hours, the aluminum hydroxide inorganic filler was centrifuged and dried thoroughly at 70 °C to obtain an aluminum hydroxide inorganic filler grafted with KH-570.

[0030] 100 parts by weight of polyolefin, 20 parts by weight of maleic anhydride grafted polyolefin compatibilizer, 1 part by weight of crosslinking initiator, the aluminum hydroxide inorganic filler grafted with KH-570 prepared in the above comparative example (in total, 53.4 parts by weight), 10 parts by weight of plasticizer, 2 parts by weight of antioxidant, and 3 parts by weight of lubricant were added to a high-speed disperser and blended at a rotation speed of 900 r / min for 20 min to obtain a mixed material. Then, the obtained mixed material was melt extruded and pelletized through a twin-screw extruder at 160°C to 210°C (zone 1: 160°C, zone 2: 175°C, zone 3: 190°C, zone 4: 200°C, zone 5: 210°C, die orifice: 200°C, screw length-diameter ratio 30:1) to obtain a sheath layer masterbatch.

[0031] The conventional insulation layer masterbatch was melted in an extruder and coaxially and uniformly extruded and wrapped on the outer surface of the conductor core, and after cooling, an insulation layer covering the conductor core was formed; an aluminum-plastic composite tape was evenly and tightly wound around the above insulation layer to form a shielding layer coaxially arranged with the insulation layer; 7 conductor cores after the above coating treatment and several filling strips for filling the gaps between these conductor cores were parallelly aligned and concentrated together and then evenly stranded. Then, these stranded conductor cores and filling strips were taken as a whole, and a non-woven fabric layer was evenly and tightly wound around them. Then, the sheath layer masterbatch prepared in this example was melted through a twin-screw extruder at 160°C to 200°C (zone 1: 160°C, zone 2: 170°C, zone 3: 185°C, zone 4: 195°C, zone 5: 200°C, die orifice: 195°C, screw length-diameter ratio 30:1) and coaxially and uniformly extruded and wrapped on the outer surface of the non-woven fabric layer, and after cooling, a sheath layer was formed.

[0032] Example 1 of Group B

[0033] During the extrusion process, no crosslinking initiation measures were adopted, and the other components and operations were the same as those in Example 1 of Group A:

[0034] 50 parts by weight of microspherical aluminum hydroxide with a particle size of 200 mesh was added to 400 parts by weight of a KH-570 dispersion solution with a mass concentration of 2% (the solvent of the dispersion solution was uniformly mixed by ethanol and water in a mass ratio of 9:1). Under a stirring state, the temperature was raised to 45°C and then kept stirring and reacting for 2 hours. Then, the aluminum hydroxide inorganic filler was centrifuged and dried sufficiently at 70°C to obtain an aluminum hydroxide inorganic filler grafted with KH-570.

[0035] 100 parts by weight of polyolefin, 20 parts by weight of maleic anhydride grafted polyolefin compatibilizer, 52 parts by weight of aluminum hydroxide inorganic filler grafted with KH-570 prepared in the above-mentioned preparation of this example, 10 parts by weight of plasticizer, 2 parts by weight of antioxidant, and 3 parts by weight of lubricant were added to a high-speed disperser and blended at a rotation speed of 900 r / min for 20 min to obtain a mixture. Then, the obtained mixture was melt-extruded and pelletized through a twin-screw extruder at 160 °C to 210 °C (zone 1: 160 °C, zone 2: 175 °C, zone 3: 190 °C, zone 4: 200 °C, zone 5: 210 °C, die orifice: 200 °C, screw length-diameter ratio: 30:1) to obtain a sheath layer masterbatch.

[0036] The conventional insulation layer masterbatch was melted in an extruder and coaxially and uniformly extruded and coated on the outer surface of the conductor core, and after cooling, an insulation layer covering the conductor core was formed; an aluminum-plastic composite tape was uniformly and tightly wound around the above-mentioned insulation layer to form a shielding layer coaxially arranged with the insulation layer; 7 conductor cores after the above-mentioned coating treatment and several filling strips for filling the gaps between these conductor cores were parallelly aligned and concentrated together and then uniformly stranded. Then, these stranded conductor cores and filling strips were taken as a whole, and a non-woven fabric layer was formed by uniformly and tightly winding a non-woven fabric on them. Then, the sheath layer masterbatch prepared in the above-mentioned preparation of this example was melted through a twin-screw extruder at 160 °C to 200 °C (zone 1: 160 °C, zone 2: 170 °C, zone 3: 185 °C, zone 4: 195 °C, zone 5: 200 °C, die orifice: 195 °C, screw length-diameter ratio: 30:1) and coaxially and uniformly extruded and coated on the outer surface of the non-woven fabric layer, and after cooling, a sheath layer was formed.

[0037] Comparative Example 1 of Group B

[0038] Use "microspherical aluminum hydroxide with a particle size of 1000 mesh" instead of "microspherical aluminum hydroxide with a particle size of 200 mesh", and the other components and operations are the same as those in Example 1 of Group B (or described as: no cross-linking initiation measures were adopted during the extrusion process, and the other components and operations are the same as those in Comparative Example 1 of Group A):

[0039] 50 parts by weight of microspherical aluminum hydroxide with a particle size of 1000 mesh was added to 400 parts by weight of a KH-570 dispersion liquid with a mass concentration of 2% (the solvent of the dispersion liquid was a uniform mixture of ethanol and water in a mass ratio of 9:1). After heating to 45 °C under stirring and keeping the temperature for stirring and reacting for 2 hours, the aluminum hydroxide inorganic filler was centrifuged and dried thoroughly at 70 °C to obtain an aluminum hydroxide inorganic filler grafted with KH-570.

[0040] 100 parts by weight of polyolefin, 20 parts by weight of maleic anhydride grafted polyolefin compatibilizer, 53.4 parts by weight of aluminum hydroxide inorganic filler grafted with KH-570 prepared in the above comparative example, 10 parts by weight of plasticizer, 2 parts by weight of antioxidant, and 3 parts by weight of lubricant were added to a high-speed disperser and blended at a speed of 900 r / min for 20 min to obtain a mixture. Then, the obtained mixture was melt-extruded and pelletized through a twin-screw extruder at 160°C to 210°C (zone 1: 160°C, zone 2: 175°C, zone 3: 190°C, zone 4: 200°C, zone 5: 210°C, die: 200°C, screw length-diameter ratio 30:1) to obtain a sheath layer masterbatch.

[0041] The conventional insulation layer masterbatch was melted in an extruder and coaxially and uniformly extruded and wrapped on the outer surface of the conductor core, and after cooling, an insulation layer covering the conductor core was formed; the aluminum-plastic composite tape was evenly and tightly wound around the above insulation layer to form a shielding layer coaxially arranged with the insulation layer; 7 conductor cores after the above coating treatment and several filling strips for filling the gaps between these conductor cores were parallelly aligned and concentrated together and then evenly stranded. Then, these stranded conductor cores and filling strips were taken as a whole, and a non-woven fabric layer was evenly and tightly wound on them. Then, the sheath layer masterbatch prepared in the above example was melted through a twin-screw extruder at 160°C to 200°C (zone 1: 160°C, zone 2: 170°C, zone 3: 185°C, zone 4: 195°C, zone 5: 200°C, die: 195°C, screw length-diameter ratio 30:1) and coaxially and uniformly extruded and wrapped on the outer surface of the non-woven fabric layer, and after cooling, a sheath layer was formed.

[0042] According to "GB / T 2406.2—2009 Plastics - Determination of burning behavior by the oxygen index method - Part 2: Room temperature test", the oxygen index of the sheath layer masterbatch obtained by extrusion granulation in the above examples and comparative examples was measured (the specification of the test sample was 90 mm × 6 mm × 3 mm, prepared with reference to "GB / T 9352-2008 Plastics - Compression molding of test specimens of thermoplastic materials". Three specimens were measured for each product of each example or comparative example, and the average value was taken, the same below);

[0043] According to "GB / T 1040.2-2006 Plastics - Determination of tensile properties - Part 2: Test conditions for moulded and extruded plastics", the mechanical properties of the sheath layer masterbatch obtained by extrusion granulation in the above examples and comparative examples were measured.

[0044] Table 1

[0045]

[0046] From the above table, without using crosslinking initiation measures in Group B, the effect of adding small particle size inorganic flame retardant fillers in Comparative Example 1 of Group B is significantly better than that of the large particle size fillers in Example 1 of Group B. This also verifies the traditional technical view that "the smaller the particle size of the inorganic filler, the higher the dispersion degree in the resin matrix, thus the better the affinity with the resin, and the more beneficial to the performance of the prepared cable sheath".

[0047] However, after further introducing crosslinking initiation measures in Group A, it is found that the effect of adding large particle size inorganic flame retardant fillers in Example 1 of Group A is very little different from that of using small particle size inorganic flame retardant fillers in Comparative Example 1 of Group A. This is because in Example 1 of Group A, through crosslinking, multiple matrix resin molecular chains are firmly connected to the surface of a large filler particle through a reactive silane coupling agent. At the same time, under the strong shear dispersion drive during extrusion processing, obvious relative displacements continuously occur between these molten matrix resin macromolecules, thus pulling the same large inorganic flame retardant filler particle in all directions and sufficiently destroying the internal cohesive force (such as van der Waals force, electrostatic force) inside the filler large particle, causing the filler large particle to disintegrate into more small particles, thus achieving an effect similar to directly using small particle size fillers in Comparative Example 1 of Group A.

[0048] At the same time, the applicant believes that in some existing measures similar to Comparative Example 1 of Group A, the particle size of the added filler particles is relatively small, so the surface area (not specific surface area) of a single particle is also small, resulting in only a few silane coupling agents being connected to a single filler particle; more importantly, after the particle size of the inorganic filler particles becomes small, the internal cohesive force of the particles will significantly increase. As a result, this measure cannot further significantly refine the inorganic filler particles and improve the filler dispersion when dealing with small particle size inorganic fillers.

Claims

1. An energy-saving filler-modified flame-retardant insulated cable, characterized in that: The cable comprises a conductor core, an insulation layer and a sheath layer from the inside to the outside in terms of layer structure. The sheath layer, calculated by weight, includes 100 parts of polyolefin, 10 to 25 parts of maleic anhydride grafted polyolefin compatibilizer, 1 to 2 parts of cross-linking initiator, 40 to 80 parts of inorganic flame retardant filler, 4 to 10 parts of silane coupling agent containing carbon-carbon double bonds, and 10 to 15 parts of processing aids, wherein the inorganic flame retardant filler is microspherical aluminum hydroxide or magnesium hydroxide with a particle size of 200 mesh to 400 mesh, and the silane coupling agent containing carbon-carbon double bonds is grafted and distributed on the inorganic flame retardant filler.

2. The energy-saving filler-modified flame-retardant insulated cable according to claim 1, characterized in that: The polyolefin includes polyethylene, polypropylene or a combination of the two.

3. The energy-saving filler-modified flame-retardant insulated cable according to claim 1, characterized in that: The maleic anhydride grafted polyolefin compatibilizer includes one or a combination of maleic anhydride grafted polyethylene and maleic anhydride grafted polypropylene.

4. The energy-saving filler-modified flame-retardant insulated cable according to claim 1, characterized in that: The silane coupling agent containing carbon-carbon double bonds includes one or a combination of two or more of vinyl trimethoxy silane, vinyl triethoxy silane, methacryloxypropyl trimethoxy silane and vinyl triisopropoxy silane.

5. The energy-saving filler-modified flame-retardant insulated cable according to claim 1, characterized in that: The processing aids include plasticizers, antioxidants and lubricants.

6. The energy-saving filler-modified flame-retardant insulated cable according to claim 1, characterized in that: The operation of grafting the silane coupling agent containing carbon-carbon double bonds on the inorganic flame retardant filler is as follows: adding the inorganic flame retardant filler into the dispersion of the silane coupling agent containing carbon-carbon double bonds at a solid-liquid ratio of 1:30-100, stirring at 30-60° C. for 1-4 hours, centrifugally separating the inorganic flame retardant filler and drying it to obtain the inorganic flame retardant filler grafted with the silane coupling agent containing carbon-carbon double bonds.

7. The energy-saving filler-modified flame-retardant insulated cable according to claim 1, characterized in that: In terms of the layer structure, the cable has a shielding layer between the insulating layer and the sheath layer.

8. The energy-saving filler-modified flame-retardant insulated cable according to claim 1, characterized in that: A plurality of conductor cores whose surfaces are covered with the insulating layer are uniformly twisted together as a whole, and the sheath layer is covered on the whole.

9. The energy-saving filler-modified flame-retardant insulated cable according to claim 1, characterized in that: The processing method of the sheath layer comprises: mixing and dispersing the polyolefin, the maleic anhydride grafted polyolefin compatibilizer, the cross-linking initiator, the inorganic flame retardant filler grafted with the silane coupling agent containing carbon-carbon double bonds, and the processing aid sufficiently, blending and melting, extruding and granulating through a screw extruder to form a sheath layer masterbatch; then, melting the sheath layer masterbatch through a screw extruder, and extruding it onto the surface of the insulating layer to form the sheath layer.

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