Semiconductor shielding resin composition, solid carbon-based cable shielding master batch, preparation method of solid carbon-based cable shielding master batch, shielding material and cable

Abstract

The invention provides a semiconductor shielding resin composition, a solid carbon-based cable shielding master batch, a preparation method of the solid carbon-based cable shielding master batch, a shielding material and a cable, the semiconductor shielding resin composition comprises a propylene-based multiphase copolymer and a multi-carbon-based nano conductive additive, the total weight of the semiconductor shielding resin composition is 100%, and the total weight of the propylene-based multiphase copolymer and the multi-carbon-based nano conductive additive is 100%. The content of the multi-element carbon-based nano conductive additive is 5-15 wt%, the multi-element carbon-based nano conductive additive comprises at least one graphene, at least one carbon nano tube and at least one acetylene black, the total weight of the multi-element carbon-based nano conductive additive is 100%, the content of the graphene is 20-40 wt%, the content of the carbon nano tube is 20-50 wt%, and the balance is acetylene black; and the ID / IG of the multi-element carbon-based nano conductive additive is more than or equal to 0.65 and less than or equal to 1.05. The semiconductor shielding resin composition and the shielding material both have a three-dimensional electric conduction coupling heat conduction double-enhanced network, and have high heat conduction performance and good electric conduction performance.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of semiconductor shielding resin composition, solid carbon-based cable shielding masterbatch and its preparation method, shielding material and cable, belong to cable material technical field. BACKGROUND

[0002] Cable shielding material is a kind of material used in the shielding layer of cable structure, and it plays an important role in high-voltage insulated cables. Its main function is to avoid the unevenness of surface electric field caused by the roughness, air gap, sharp burr and other reasons on the surface of the conductor, and to reduce the probability of insulation breakdown due to partial discharge and further development to breakdown. With the development of cable technology, cable shielding material has also undergone continuous improvement and innovation.

[0003] Initially, the semiconductive layer was mainly implemented by wrapping semiconductive cloth, but the wrapping of semiconductive cloth had obvious defects, such as the problem of voids, the problem of smoothness, the problem of strength and aging performance, etc. Although some medium and high voltage cable structures still use semiconductive cloth to bundle the center conductor, the semiconductive shielding layer of polymer composite material is an indispensable cable structure. The semiconductive shielding material belongs to a composite material with polymer as the matrix, which is composed of conductive fillers and other additives in the high molecular matrix.

[0004] The use of carbon black in cable shielding material is a common technique, which can provide excellent electrical conductivity and shielding effect. With the development of cable industry, carbon black technology has been continuously improved and applied. In cable shielding material, carbon black is usually added in the form of particles or nanoparticles. Carbon black has high electrical conductivity, which can effectively shield electromagnetic interference and static electricity, protecting the signal transmission inside the cable. Carbon black also has excellent wear resistance and aging resistance, which can improve the service life of the cable. Currently, the surface of carbon black is usually modified in the field to improve its dispersibility and increase its compatibility with other materials. The modified carbon black can be more uniformly dispersed in the shielding material, improving the shielding effect and mechanical properties. However, there are still some problems in the use of carbon black in cable shielding material. First of all, the amount of carbon black added and its dispersibility have a great influence on the shielding effect and mechanical properties, but it is difficult to find a balance. Excessive addition of carbon black will cause the material to become hard and brittle, affecting the flexibility of the cable, while insufficient addition of carbon black will reduce the shielding effect and increase the electromagnetic interference of the cable. Secondly, the electrical conductivity and shielding effect of carbon black may decrease over time, which may gradually reduce the performance of the cable.

[0005] Carbon black as a cable shielding material has mature technology development, but there are still some problems to be solved, and it is still necessary to improve its dispersibility and compatibility to further improve the performance and reliability of cable shielding material.

[0006] To address these issues, several novel cable shielding materials have been developed in recent years. For example, composite conductor materials are used in cable shielding layers. These materials offer excellent shielding performance while being lightweight, corrosion-resistant, and easy to process. Furthermore, new conductive materials, such as conductive polymers and conductive fibers, are also being used in cable shielding. However, current cable shielding materials still suffer from several problems, such as insufficient thermal and electrical conductivity, poor volume resistivity temperature stability (PTC effect), and the potential for aging and performance degradation during long-term use, requiring further improvements to adapt to more complex electromagnetic environments.

[0007] In summary, while cable shielding materials are constantly being developed and innovated, they still face some challenges and problems, requiring further improvement in thermal and electrical conductivity.

[0008] To further illustrate the existing technology, the applicant provides the following relevant documents and explanations.

[0009] CN108178854 A discloses an electromagnetic shielding rubber, its preparation method, and an electronic device thereof. The electromagnetic shielding rubber comprises: a rubber matrix, additives, carbon nanotubes, graphene, acetylene black, silver powder, copper powder, silver-plated glass microspheres, silver-plated nickel powder, nickel powder, iron oxide, and nickel oxide. This electromagnetic shielding rubber achieves a three-dimensional electromagnetic shielding protection system by mixing the rubber matrix with fillers such as carbon nanotubes, graphene, additives, acetylene black, silver powder, copper powder, silver-plated glass microspheres, silver-plated nickel powder, nickel powder, iron oxide, and nickel oxide, through one-dimensional, two-dimensional, and three-dimensional filler compounding. This enhances the shielding effectiveness of the electromagnetic shielding rubber while simultaneously reducing the amount of filler added and improving the mechanical properties of the electromagnetic shielding rubber. Based on 100 parts by weight of the rubber matrix, the amount of additives added is 1-5 parts by weight, the amount of carbon nanotubes added is 1-20 parts by weight, the amount of graphene added is 1-20 parts by weight, the amount of acetylene black added is 1-20 parts by weight, the amount of silver powder added is 20-200 parts by weight, the amount of copper powder added is 20-200 parts by weight, the amount of silver-plated glass microspheres added is 20-200 parts by weight, the amount of silver-plated nickel powder added is 20-200 parts by weight, the amount of nickel powder added is 20-200 parts by weight, the amount of iron oxide added is 20-200 parts by weight, and the amount of nickel oxide added is 20-200 parts by weight.

[0010] To address the problem that existing electromagnetic shielding rubber technologies require the addition of large amounts of metal oxides or metal powders to the rubber matrix to construct conductive or magnetic networks, and that poor interfacial adhesion between metal oxides / powders and rubber leads to a decline in the mechanical properties of the rubber matrix with excessive filling, this patent application aims to provide an electromagnetic shielding rubber with excellent shielding effectiveness while improving its mechanical properties using a small amount of filler. However, this patent application contains too many components and mixes fillers with different properties, such as carbon materials, metals, and glass, resulting in uneven distribution of the rubber matrix and agglomeration of various filler types, which in turn causes a significant deterioration in shielding performance, mechanical properties, and thermal conductivity.

[0011] CN110498964 A discloses a thermoplastic semiconductive shielding material for high-voltage cables, wherein the material comprises the following components in parts by weight: 15-40 parts polypropylene, 30-50 parts polyolefin copolymer elastomer, 15-40 parts conductive carbon black, 0.1-5.0 parts composite conductive powder, 0.5-10 parts lubricant and dispersant, and 0.5-5.0 parts antioxidant; the composite conductive powder is MXene-graphene, MXene-carbon nanotube, or graphene-carbon nanotube composite conductive powder. By preparing composite two-dimensional conductive fillers, such as two-dimensional layered transition metal carbides MXene-graphene (MXene-GNS), MXene-carbon nanotube (MXene-CNT), or graphene-carbon nanotube (GNS-CNT) composite conductive fillers, a highly interconnected conductive network pathway is provided, allowing the addition of a small amount of a second conductive component to significantly reduce the volume resistivity of the composite semiconductive shielding material, improve resistivity temperature stability, and ensure excellent electrical performance. At the same time, the amount of conductive carbon black used was reduced, and the processing performance of the shielding material was improved.

[0012] This patent application addresses the shortcomings of existing high-voltage cable semiconducting shielding materials. In these materials, the volume expansion of the non-crosslinked thermoplastic polymer matrix disrupts the carbon black conductive network upon temperature increases, leading to a rapid rise in volume resistivity. Furthermore, to achieve the required low resistivity and reduce temperature dependence, a high carbon black content is necessary, increasing the melt viscosity and hindering processing. The patent aims to overcome these deficiencies by providing a high-voltage cable thermoplastic semiconducting shielding material with low volume resistivity and low temperature dependence. However, it does not consider the electrothermal aging and insulation degradation caused by poor thermal conductivity, has a complex preparation method, and suffers from filler dispersion issues within the matrix.

[0013] CN108864527A discloses a semi-conductive shielding layer material for polypropylene insulation of high-voltage cables, comprising, by weight: 20-50 parts of polypropylene base material, 50-80 parts of elastomer base material, 20-55 parts of conductive carbon black, 0.5-2.5 parts of synergistic antioxidant, 0.01-3.0 parts of copper inhibitor, and 0.5-10 parts of lubricant and dispersant; wherein the total amount of polypropylene base material and elastomer base material is 100 parts, and the polypropylene base material is a blend of homopolymer polypropylene and copolymer polypropylene in a weight ratio of 0-10:1, wherein the melt index of the homopolymer polypropylene is 1.0-5.0 g / 10min, and the melt index of the copolymer polypropylene is 1.0-5.0 g / 10min. It also contains no more than 1.0 part of graphene by weight. The semiconductive shielding layer material provided in this patent application has advantages such as excellent mechanical properties, good copper resistance, non-crosslinking, and fast extrusion speed; however, it cannot significantly reduce the volume resistivity of the shielding material or the temperature dependence of volume resistivity, thus the improvement in resistivity stability is limited. In addition, its thermal conductivity and electrical conductivity still need further improvement.

[0014] Therefore, how to simultaneously enhance the thermal conductivity and electrical conductivity of conductive carbon black in shielding materials and enable the shielding materials to have excellent temperature stability of volume resistivity, i.e., a lower PTC effect, remains a problem that urgently needs to be solved in this field. Summary of the Invention

[0015] To address the aforementioned shortcomings and deficiencies, the present invention aims to provide a semiconductor shielding resin composition, a solid carbon-based cable shielding masterbatch and its preparation method, a shielding material, and a cable.

[0016] To achieve the above objectives, in one aspect, the present invention provides a semiconductor shielding resin composition, wherein the semiconductor shielding resin composition comprises a propylene-based multiphase copolymer and a multi-component carbon-based nano-conductive additive, wherein, based on 100% of the total weight of the semiconductor shielding resin composition, the content of the multi-component carbon-based nano-conductive additive is 5-15 wt%, comprising at least one graphene, at least one carbon nanotube, and at least one acetylene black, and based on 100% of the total weight of the multi-component carbon-based nano-conductive additive, the content of graphene is 20-40 wt%, the content of carbon nanotube is 20-50 wt%, and the balance is acetylene black, and the multi-component carbon-based nano-conductive additive has a content of I D / I G Satisfying 0.65≤I D / I G ≤1.05, preferably, 0.85≤I D / I G ≤0.95.

[0017] The present invention does not impose specific requirements on the content of propylene-based multiphase copolymer in the semiconductor shielding resin composition. The content can be reasonably determined based on the content of multi-component carbon-based nano-conductive additives, or the total content of multi-component carbon-based nano-conductive additives and additives such as antioxidants and metal passivators, as long as the total weight of each component is 100%.

[0018] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the propylene-based multiphase copolymer includes a matrix phase and an elastic phase. The matrix phase includes propylene homopolymer or propylene copolymer, and the elastic phase includes propylene-α-olefin copolymer, preferably propylene-1-butene copolymer.

[0019] In one specific embodiment of the semiconductor shielding resin composition described above in this invention, the propylene-α-olefin copolymer used as the elastic phase has an α-olefin content of ≥20wt% and ≤30wt%.

[0020] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the propylene copolymer includes propylene-α-olefin copolymer and / or propylene-ethylene copolymer, preferably propylene-ethylene copolymer.

[0021] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the α-olefin is one or a combination of several C4-C8 olefins, preferably one or a combination of several of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene.

[0022] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the propylene-based multiphase copolymer includes a matrix phase and an elastic phase, the matrix phase includes propylene homopolymer or propylene copolymer, and the elastic phase includes propylene-α-olefin copolymer.

[0023] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the propylene copolymer includes propylene-α-olefin copolymer and / or propylene-ethylene copolymer.

[0024] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the content of o-dichlorobenzene solubles in the propylene-based multiphase copolymer is 30.0-45.0 wt%.

[0025] In a specific embodiment of the semiconductor shielding resin composition described above in this invention, the propylene-based multiphase copolymer is prepared by a method comprising the following steps:

[0026] After pre-contacting, the catalyst system is continuously fed into the first polymerization reactor to complete the first stage of polymerization. Then, propylene is added to the first polymerization reactor and hydrogen and another olefin comonomer (α-olefin and / or ethylene) are introduced to carry out the second stage of polymerization to obtain a propylene copolymer; or propylene homopolymer is prepared in the first polymerization reactor using propylene as a raw material.

[0027] The product obtained from the first polymerization reactor is fed into the second polymerization reactor, and propylene and α-olefins are added to the second polymerization reactor to carry out a third-stage polymerization reaction. The reactants obtained from the second polymerization reactor are inactivated and dried to obtain a propylene copolymer or a propylene homopolymer and a propylene-α-olefin copolymer forming a propylene multiphase copolymer.

[0028] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the catalyst system includes a main catalyst, a co-catalyst, and an external electron donor, wherein the main catalyst includes a Ziegler-Natta catalyst, a metallocene catalyst, an organometallic catalyst, or a coordination catalyst, the co-catalyst includes organoaluminum compounds, and the external electron donor includes organosilicon compounds.

[0029] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the main catalysts such as Ziegler-Natta catalyst, metallocene catalyst, organometallic catalyst or coordination catalyst are all conventional substances and can be selected as needed. These main catalysts can be obtained commercially or prepared using existing conventional methods.

[0030] The organoaluminum used as the cocatalyst includes one or a combination of several of the following: trialkylaluminum (e.g., trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, trihexylaluminum, and trioctylaluminum), diethylaluminum monochloro, diisobutylaluminum monochloro, diethylaluminum monochloro, and diethylaluminum monochloro.

[0031] Organosilicon compounds that act as external electron donors include one or more of the following: isobutyltriethoxysilane, diisopropyldimethoxysilane, cyclohexylmethyldimethoxysilane, tetramethoxysilane, tetraethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylphenoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyl tert-butyldimethoxysilane, methyl isopropyldimethoxysilane, diphenoxydimethoxysilane, diphenyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, (1,1,1-trifluoro-2-propyl)-2-ethylpiperidinyldimethoxysilane, and (1,1,1-trifluoro-2-propyl)-methyldimethoxysilane.

[0032] In a specific embodiment of the semiconductor shielding resin composition described above in this invention, the molar ratio of the organoaluminum compound as the co-catalyst and the organosilicon compound as the external electron donor is 1:1-200:1, preferably 10:1-50:1, calculated as aluminum / silicon.

[0033] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the α-olefin is a C4-C8 olefin, including one or a combination of several of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene.

[0034] In a specific embodiment of the semiconductor shielding resin composition described above in this invention, the temperature of the first stage polymerization reaction, the second stage polymerization reaction, and the third stage polymerization reaction is 40-100°C, preferably 60-100°C, and the residence time of each stage polymerization reaction is 30 min-10 h.

[0035] In the method for preparing the propylene multiphase copolymer described above in this invention, the first polymerization reaction (including the first-stage polymerization reaction and the second-stage polymerization reaction) can be carried out in the liquid phase, and the second polymerization reaction (i.e., the third-stage polymerization reaction) can be carried out in the gas phase; both the first and second polymerization reactions can also be carried out in the gas phase. When the polymerization reaction is carried out in the liquid phase, the polymerization pressure is preferably in the range of 3.0-4.5 MPa. When the polymerization reaction is carried out in the gas phase, the polymerization temperature is preferably 60-90℃, and the polymerization pressure is preferably 1.0-3.0 MPa. When the polymerization reaction is carried out in the gas phase, the gas phase reactor used can be a gas phase fluidized bed, a gas phase moving bed, or a gas phase stirred bed reactor, etc.

[0036] In one specific embodiment of the semiconductor shielding resin composition described above in this invention, the content of the multi-component carbon-based nano-conductive additive is 8-12 wt%.

[0037] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the graphene content is 25-35 wt%, the carbon nanotube content is 30-40 wt%, and the balance is acetylene black, based on the total weight of the multi-component carbon-based nano-conductive additives as 100%.

[0038] In this invention, I D / I G These are structural parameters of carbon-based materials, representing the sp2 hybridization of carbon atoms (I0, I2, I3) in carbon-based materials. D ) and sp3 hybridized carbon atoms (I G The relative content of ). In the semiconductor shielding resin composition of the present invention, when the I of the multi-component carbon-based nano-conductive additive D / I GWhen the value is ≤1.05, it can not only improve the electrical conductivity and anti-interference ability of the material, that is, stabilize the volume resistivity of the material and reduce the PTC effect, but also further improve the thermal conductivity and electrical conductivity.

[0039] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the composition further comprises 0.01-1 wt% antioxidant, based on 100% of the total weight of the semiconductor shielding resin composition. Preferably, the antioxidant content is 0.1-0.5 wt%. The antioxidant contained in the semiconductor shielding resin composition of this invention can improve the long-term stability of the material.

[0040] In one specific embodiment of the semiconductor shielding resin composition described above in this invention, the antioxidant includes pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(2,4-di-tert-butylphenyl) phosphite, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethyl... It is one or a combination of several of the following: (-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid, N,N-bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, octadecyl 3,3-thiodipropionate, and n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0041] In a specific embodiment of the semiconductor shielding resin composition described above, the semiconductor shielding resin composition, based on 100% of its total weight, further comprises 0.05-1 wt% of a metal passivating agent, wherein the metal passivating agent includes substances such as amines, hydrazines, or azoles. The metal passivating agent contained in the semiconductor shielding resin composition of the present invention can inhibit the catalytic aging of heavy metal ions in the conductor layer.

[0042] As a specific embodiment of the semiconductor shielding resin composition described above in this invention, the metal passivating agent includes one or a combination of several of the following: MD1024 (N,N'-bis[β(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine), MDA-5 (N-salicylamide phthalimide), and SR-697 (2,2-oxamidobis-[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid).

[0043] On the other hand, the present invention also provides a solid carbon-based cable shielding masterbatch, wherein the raw materials of the solid carbon-based cable shielding masterbatch include the semiconductor shielding resin composition described above.

[0044] In another aspect, the present invention also provides a method for preparing the above-mentioned solid carbon-based cable shielding masterbatch, wherein the preparation method includes:

[0045] Step (1): Graphene, carbon nanotubes, acetylene black, propylene-based multiphase copolymer and surfactant are mixed evenly in an organic solvent to obtain a dispersion;

[0046] Step (2): Centrifuge and filter the dispersion;

[0047] Step (3): The solution obtained in step (2) is dried to evaporate the organic solvent in it, and a solid carbon-based cable shielding masterbatch is obtained.

[0048] In one specific embodiment of the preparation method described above in this invention, in step (1), graphene, carbon nanotubes, acetylene black, and surfactant can be premixed in an organic solvent, and then propylene-based multiphase copolymer can be added and mixed evenly to obtain a dispersion; alternatively, graphene, carbon nanotubes, acetylene black, propylene-based multiphase copolymer, and surfactant can be mixed simultaneously or in batches in an organic solvent. This invention does not specify the exact substance of the organic solvent and can select it reasonably as needed. For example, in some embodiments of this invention, the organic solvent is ethanol, etc.

[0049] As a specific embodiment of the preparation method described above in this invention, in step (1), the surfactant includes one or more of the following: sodium dodecyl sulfate, sodium hexadecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium hexadecyl sulfonate, sodium hexadecylbenzene sulfonate, sodium stearate, sodium dodecyl diphenyl ether disulfonate, sodium secondary alkyl sulfonate, ammonium primary aminosulfonate, polyethylene glycol, polyether, and alkylolamide. Furthermore, this invention does not specify a particular amount of surfactant; it can be reasonably adjusted according to actual operational needs.

[0050] As a specific embodiment of the preparation method described above in this invention, in step (1), the uniform mixing can be achieved by ultrasound, wherein the ultrasound temperature is 30-50℃ and the time is 20-40min.

[0051] In step (2) of the preparation method described above, the dispersion is centrifuged and filtered so that the graphene, carbon nanotubes and acetylene black in the dispersion form a three-dimensional conductive and thermally conductive dual-enhanced network in the propylene-based multiphase copolymer (i.e., inside). That is, the network is a three-dimensional network and is formed by graphene, carbon nanotubes and acetylene black, which has both conductive and thermally conductive effects.

[0052] The present invention does not make specific requirements on the drying temperature and time in step (3) of the preparation method described above, as long as it can ensure that the organic solvent in the solution obtained in step (2) can be evaporated to obtain a solid semiconductor shielding resin composition.

[0053] In this invention, when the semiconductor shielding resin composition further includes additives such as antioxidants and metal passivators, the preparation method of the solid carbon-based cable shielding masterbatch includes:

[0054] In step (1), graphene, carbon nanotubes, acetylene black, propylene-based multiphase copolymer, additives and surfactants are mixed evenly in an organic solvent to obtain a dispersion; then steps (2) and (3) are performed to obtain the solid carbon-based cable shielding masterbatch.

[0055] And / or,

[0056] The process includes: first, preparing a propylene-based multiphase copolymer according to the preparation method shown above; then, mixing the polymer powder obtained from the reactants in the second polymerization reactor after inactivation and drying treatment with additives; and finally, melt-extruding and granulating the mixture to obtain a mixture of the propylene-based multiphase copolymer and additives; subsequently, proceeding to steps (1)-(3) to obtain the solid carbon-based cable shielding masterbatch. That is, in this invention, the additives can be added in step (1), added during the preparation of the propylene-based multiphase copolymer, or added simultaneously in both steps.

[0057] In another aspect, the present invention also provides a shielding material, wherein the shielding material is obtained by extrusion of the above-mentioned solid carbon-based cable shielding masterbatch and propylene-based multiphase copolymer.

[0058] In one specific embodiment of the shielding material described above in this invention, the extrusion is performed using a stretch rheological plasticizing extrusion device. The temperature of each section is 180-250℃, the rotor speed is 50-120 rpm, the feeder speed is 20-80 rpm, and the length-to-diameter ratio is 30-40. Under these parameter conditions, the stretch rheological plasticizing extrusion of this invention can further achieve the dispersion of multi-element carbon-based nano-conductive additives, forming a three-dimensional conductive-coupled and thermally-conductive dual-reinforcement network. The stretch rheological plasticizing extrusion device is a conventional existing device.

[0059] This invention does not specify the amount of propylene-based multiphase copolymer used in the preparation of the shielding material described above. The amount can be reasonably adjusted according to actual on-site operational needs, as long as the objective of this invention is achieved. Furthermore, the propylene-based multiphase copolymer can be prepared using the method described above.

[0060] Finally, the present invention also provides a cable, comprising a conductor, an inner shielding layer covering the conductor, an insulation layer covering the inner shielding layer, and an outer shielding layer covering the insulation layer, wherein the inner shielding layer and / or the outer shielding layer are made of the shielding materials described above.

[0061] In one specific embodiment of the cable described above in this invention, the cable is a thermoplastic cable.

[0062] In the cable provided by the present invention, the inner shielding layer and / or the outer shielding layer, which are made of shielding material, are recyclable layers.

[0063] Compared with the prior art, the beneficial technical effects achieved by the present invention include:

[0064] The semiconductor shielding resin composition and shielding material provided by the present invention both have a three-dimensional conductive coupling and thermally conductive dual-enhanced network, which has high thermal conductivity and good electrical conductivity.

[0065] The semiconductor shielding resin composition and shielding material provided by this invention have a weak PTC effect, which solves the common problem of filled semiconductive polymers and improves the safety of cable operation.

[0066] The semiconductor shielding resin composition and shielding material provided by the present invention have high surface smoothness and good extrusion processing performance. Detailed Implementation

[0067] It should be noted that the term "comprising" and any variations thereof in the specification and claims of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0068] The "range" disclosed in this invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0069] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0070] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in this invention can be combined with each other to form new technical solutions.

[0071] In this invention, unless otherwise specified, all technical features and preferred features mentioned in this invention can be combined with each other to form new technical solutions.

[0072] In this invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0073] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the appendices and embodiments. The embodiments described below are some, but not all, embodiments of this invention, and are only used to illustrate the invention, and should not be considered as limiting the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0074] Analysis and testing methods:

[0075] o-Dichlorobenzene soluble content:

[0076] This invention analyzes the soluble fraction of propylene-based multiphase copolymers using crystallization and fractionation equipment (e.g., A-TREF or CEF) from PolymerCharts. The experimental procedure is as follows:

[0077] The propylene-based multiphase copolymer was dissolved in o-dichlorobenzene at 160 °C. After 120 minutes, the temperature was lowered to 95 °C at a rate of 30 °C / min, and then crystallized to 35 °C at a rate of 2 °C / min. Simultaneously, o-dichlorobenzene was pumped at a rate of 0.05 mL / min and the column was slowly rinsed. After crystallization, the temperature was increased to 150 °C at a rate of 4 °C / min and 1 mL / min. The sample information during the rinsing process was recorded using an IR-5 infrared detector to obtain the crystallization rinsing fractionation curve and the content of o-dichlorobenzene solubles at room temperature.

[0078] Volume resistivity and PTC intensity:

[0079] According to the national standard GB / T 3048.3-2007, the volume resistivity of the target cable shielding material was measured using a four-electrode system. The experiments were conducted at 30℃, 50℃, 60℃, 70℃, 90℃ and 110℃. After the experiment, the logarithmic difference between the volume resistivity at 110℃ and the volume resistivity at 30℃ was taken as the PTC intensity.

[0080] Filled semiconductive polymers all exhibit a positive temperature coefficient (PTC) effect, where volume resistivity increases with temperature. A severe PTC effect can reduce or even eliminate the effectiveness of the shielding layer, thus affecting cable safety. Therefore, cable shielding materials must have high temperature stability in volume resistivity, i.e., low PTC strength.

[0081] Surface smoothness:

[0082] The target cable shielding material is extruded into strips with a thickness of 0.3 mm using a single-screw extruder equipped with a flat die; these are the test strips. The test strips are then maintained under constant mechanical tension at a certain speed by a casting roller and moved by a winding machine. The strips are advanced to the measurement area of ​​an optical inspection system. An online camera connected to a computer records images of the extruded strip surface and performs image analysis. Finally, the number of defects on the test strip surface is classified according to size and shape, yielding a percentage per meter. 2 The number of defects or bumps.

[0083] DC breakdown strength:

[0084] The DC breakdown strength of the target shielding material was tested according to the method specified in GB / T 1408-2006. During the test, the output AC voltage was 0-100kV, using 10mm diameter ball-to-ball copper electrodes with a voltage ramp rate of 2kV / s. The thin film sample diameter was 15cm and the thickness was 0.20mm. Each sample group had at least 10 measurement points. Both the test sample and the electrodes were immersed in silicone oil (treated in a 70℃ vacuum oven for 24 hours before testing) to prevent surface discharge.

[0085] Thermal conductivity:

[0086] The target shielding material was hot-pressed into a circular sheet with a diameter of 30 mm and a thickness of 2 mm. Thermally conductive silver grease was then applied to both sides, and the sheet was placed between hot and cold electrodes for thermal conductivity testing. The applied pressure was approximately 300 N, and the test stabilization time was 300 s.

[0087] Preparation Example 1

[0088] This preparation example provides a propylene-based multiphase copolymer, which is prepared by a method including the following specific steps:

[0089] 1g of MgCl2-supported Ti catalyst, 8.0g of triethylaluminum, and 1.1g of isobutyltriethoxysilane were pre-contaminated at 10°C for 30min and then continuously fed into the first polymerization reactor to complete the first stage polymerization reaction. The temperature of the first stage polymerization reaction was 70°C and the reaction pressure was 4.0MPa. Liquid propylene and ethylene were added to the first polymerization reactor and hydrogen was introduced at the same time. The temperature was maintained at 70°C and the reaction pressure was 4.0MPa. After the materials were kept in the first polymerization reactor for 1 hour, propylene-ethylene copolymer was obtained.

[0090] The product obtained from the first polymerization reactor is fed into the second polymerization reactor. Propylene and 1-butene are added to the second polymerization reactor to carry out a polymerization reaction. The polymerization reaction temperature in this stage is 75°C, the reaction pressure is 1.5 MPa, and the residence time of the material in the reactor is 3 hours.

[0091] The reaction product obtained from the second polymerization reactor was subjected to wet nitrogen gas to remove the activity of unreacted catalyst and then heated and dried to obtain polymer powder.

[0092] The polymer powder was mixed with pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] at an antioxidant content of 0.2% of the total weight of the semiconductor shielding resin composition, and then melt-extruded and granulated to obtain a mixture of propylene-based multiphase copolymer and antioxidant.

[0093] The content of o-dichlorobenzene solubles in the propylene-based multiphase copolymer was measured according to the analytical testing method provided above. The content of o-dichlorobenzene solubles in the propylene-based multiphase copolymer obtained in this preparation example of the present invention is 40.0 wt%.

[0094] Examples 1-5

[0095] This embodiment provides a series of cable shielding materials, denoted as EX1-EX5, which are prepared using a method including the following specific steps:

[0096] The mixture of propylene-based multiphase copolymer and antioxidant provided in Preparation Example 1, along with the multi-carbon-based nano-conductive additive, was dispersed in 200 mL of ethanol, and 1.5 g of sodium dodecyl sulfonate was added. The mixture was ultrasonically dispersed at 30 °C for 20 min to obtain a dispersion.

[0097] After the dispersion is poured into the mold, it is centrifuged and filtered to allow the graphene, carbon nanotubes and acetylene black in the dispersion to form a three-dimensional conductive and thermally conductive dual-enhanced network inside the propylene-based multiphase copolymer composition.

[0098] The solution in the mold is dried to evaporate the solvent, ultimately yielding a solid carbon-based cable shielding masterbatch.

[0099] The solid carbon-based cable shielding masterbatch and the propylene-based multiphase copolymer provided in Preparation Example 1 are then mixed and extruded using a stretch rheology plasticizing extrusion device to obtain a semiconductor shielding material, i.e., a cable shielding material. During extrusion, the temperature of each section of the stretch rheology plasticizing extrusion device is 220°C, the rotor speed is 90 rpm, the feeder speed is 50 rpm, and the length-to-diameter ratio of the stretch rheology plasticizing extrusion device is 35.

[0100] Comparative Examples 1-10

[0101] This comparative example provides a series of cable shielding materials, denoted as CE1-CE10, which differ from the examples only in the components and content of each component in the multi-component carbon-based nano-conductive additive, and the I content of the multi-component carbon-based nano-conductive additive. D / I G The mass ratio of propylene-based multiphase copolymers to multi-carbon-based nano-conductive additives.

[0102] In Examples 1-5 and Comparative Examples 1-10 of this invention, the specific components and content of each component in the multi-component carbon-based nano-conductive additive, and the I of the multi-component carbon-based nano-conductive additive are described. D / I G The mass ratios of the propylene-based multiphase copolymer and the multi-component carbon-based nano-conductive additives are shown in Table 1 below.

[0103] Table 1

[0104]

[0105] Comparative Example 11

[0106] This comparative example provides a cable shielding material, denoted as CE11, which differs from Example 2 only in that: instead of preparing a solid carbon-based cable shielding masterbatch, a propylene-based multiphase copolymer and a multi-component carbon-based nano-conductive additive are directly mixed and extruded in a stretching rheological plasticizing extrusion apparatus. The specific operation steps are as follows:

[0107] The propylene-based multiphase copolymer, graphene, carbon nanotubes, and acetylene black provided in Preparation Example 1 were mixed and extruded through a stretch rheology plasticizing extrusion apparatus to obtain a semiconductor shielding material, i.e., a cable shielding material. During extrusion, the temperature of each section of the stretch rheology plasticizing extrusion apparatus was 220°C, the rotor speed was 90 rpm, the feeder speed was 50 rpm, and the length-to-diameter ratio of the stretch rheology plasticizing extrusion apparatus was 35.

[0108] Comparative Example 12

[0109] This comparative example provides a cable shielding material, denoted as CE12, which differs from Example 2 only in that the mixing and extrusion steps use a conventional twin-screw extruder.

[0110] Comparative Example 13

[0111] This comparative example provides a cable shielding material, denoted as CE13, which differs from Example 2 only in that the aspect ratio of the stretch rheological plasticizing extrusion equipment is 25.

[0112] Comparative Example 14

[0113] This comparative example provides a cable shielding material, denoted as CE14, which differs from Example 2 only in that the aspect ratio of the stretch rheological plasticizing extrusion equipment is 45.

[0114] Test case

[0115] This test example, following the analytical testing methods provided above, examines the DC breakdown strength, volume resistivity at 30℃, volume resistivity at 110℃, and per m of EX1-EX5 and CE1-CE14, respectively. 2 The number of bulges or defects, thermal conductivity, and PTC strength were tested, and the experimental results are shown in Table 2 below.

[0116] Table 2

[0117]

[0118]

[0119] As can be seen from Table 2 above, the cable shielding materials provided in Examples 1-5 of the present invention exhibit excellent DC breakdown strength, volume resistivity at 30°C, volume resistivity at 110°C, number of bulges or defects per m2, thermal conductivity, and PTC strength.

[0120] Compared to Example 4, in Comparative Examples 1 and 3, only the amounts of graphene and carbon nanotubes are outside the scope of protection claimed in this application; the performance of the cable shielding materials obtained from these examples is significantly inferior to that of the cable shielding material provided in Example 4. Similarly, compared to Example 5, in Comparative Examples 2 and 4, only the amounts of graphene and carbon nanotubes are outside the scope of protection claimed in this application; the performance of the cable shielding materials obtained from these examples is also significantly inferior to that of the cable shielding material provided in Example 5. This indicates that the performance of the multi-component carbon-based nano-conductive additives is significantly inferior to that of the cable shielding material provided in Example 5. D / I G Provided that the mass ratio of propylene-based multiphase copolymer to multi-carbon-based nano-conductive additive is the same and meets the requirements, the amount of graphene and carbon nanotubes in the multi-carbon-based nano-conductive additive must be within the range of protection claimed in this application in order to obtain a high-performance cable shielding material.

[0121] Compared to Example 2, the only difference in Comparative Examples 5-8 is the composition of the multi-component carbon-based nano-conductive additives, namely, they all contain thermally cracked carbon black. The performance of the cable shielding materials obtained from them is significantly inferior to that of the cable shielding material provided in Example 2. This indicates that, under the same conditions and requirements, the multi-component carbon-based nano-conductive additives must simultaneously contain graphene, carbon nanotubes, and acetylene black to obtain a high-performance cable shielding material.

[0122] Compared to Example 2, in Comparative Examples 9 and 10, only the mass ratio of propylene-based multiphase copolymer to multi-carbon-based nano-conductive additives was outside the scope of protection claimed in this application. The performance of the cable shielding materials obtained from these examples was significantly inferior to that of the cable shielding material provided in Example 2. This indicates that, under the same conditions and requirements, the mass ratio of propylene-based multiphase copolymer to multi-carbon-based nano-conductive additives must be within the scope of protection claimed in this application in order to obtain a high-performance cable shielding material.

[0123] Compared to Example 2, Comparative Example 11 differs only in its preparation method, Comparative Example 12 differs only in the extrusion equipment used, and Comparative Examples 13-14 differ only in the aspect ratio of the stretch rheoplastic extrusion equipment. The performance of the cable shielding materials obtained from these examples is significantly inferior to that of the cable shielding material provided in Example 2. This indicates that, under the same conditions and requirements, the preparation method, the extrusion equipment used, and the aspect ratio of the stretch rheoplastic extrusion equipment must be within the range claimed in this application to obtain a high-performance cable shielding material.

[0124] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical inventions, and technical inventions in this invention can be freely combined and used.

Claims

1. A semiconductor shielding resin composition, characterized in that, The semiconductor shielding resin composition comprises a propylene-based multiphase copolymer and a multi-component carbon-based nano-conductive additive. The multi-component carbon-based nano-conductive additive, based on 100% of the total weight of the semiconductor shielding resin composition, has a content of 5-15 wt%, comprising at least one graphene, at least one carbon nanotube, and at least one acetylene black. Based on 100% of the total weight of the multi-component carbon-based nano-conductive additive, the graphene content is 20-40 wt%, the carbon nanotube content is 20-50 wt%, and the balance is acetylene black. Furthermore, the multi-component carbon-based nano-conductive additive has a content of I... D / I G Satisfying 0.65≤I D / I G ≤1.

05.

2. The semiconductor shielding resin composition according to claim 1, characterized in that, The propylene-based multiphase copolymer includes a matrix phase and an elastic phase. The matrix phase includes propylene homopolymer or propylene copolymer, and the elastic phase includes propylene-α-olefin copolymer.

3. The semiconductor shielding resin composition according to claim 2, characterized in that, The propylene copolymers include propylene-α-olefin copolymers and / or propylene-ethylene copolymers.

4. The semiconductor shielding resin composition according to claim 1, characterized in that, The content of o-dichlorobenzene solubles in the propylene-based multiphase copolymer is 30.0-45.0 wt%.

5. The semiconductor shielding resin composition according to any one of claims 1-4, characterized in that, The propylene-based multiphase copolymer is prepared by a method comprising the following steps: After pre-contacting, the catalyst system is continuously fed into the first polymerization reactor to complete the first stage of polymerization. Then, propylene is added to the first polymerization reactor and hydrogen and another olefin comonomer are introduced to carry out the second stage of polymerization to obtain a propylene copolymer; or propylene homopolymer is prepared in the first polymerization reactor using propylene as a raw material. The product obtained from the first polymerization reactor is fed into the second polymerization reactor, and propylene and α-olefins are added to the second polymerization reactor to carry out a third-stage polymerization reaction. The reactants obtained from the second polymerization reactor are then inactivated and dried to obtain a propylene multiphase copolymer.

6. The semiconductor shielding resin composition according to claim 5, characterized in that, The catalyst system includes a main catalyst, a co-catalyst, and an external electron donor. The main catalyst includes a Ziegler-Natta catalyst, a metallocene catalyst, an organometallic catalyst, or a coordination catalyst. The co-catalyst includes an organoaluminum compound. The external electron donor includes an organosilicon compound.

7. The semiconductor shielding resin composition according to claim 5, characterized in that, The α-olefin is a C4-C8 olefin, including one or a combination of several of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene.

8. The semiconductor shielding resin composition according to claim 5, characterized in that, The temperatures for the first, second, and third stages of polymerization are 40-100℃, and the residence time for each stage is 30 min-10 h.

9. The semiconductor shielding resin composition according to claim 1, characterized in that, The semiconductor shielding resin composition, by weight of 100%, also contains 0.01-1 wt% antioxidant.

10. The semiconductor shielding resin composition according to claim 9, characterized in that, The antioxidants include one or a combination of several of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(2,4-di-tert-butylphenyl) phosphite, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid, N,N-bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, octadecyl 3,3-thiodipropionate, and n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

11. The semiconductor shielding resin composition according to claim 1, characterized in that, The semiconductor shielding resin composition, by weight of 100%, further comprises 0.05-1 wt% of a metal passivating agent, wherein the metal passivating agent comprises an amine, hydrazine, or azole.

12. A solid carbon-based cable shielding masterbatch, characterized in that, The raw materials of the solid carbon-based cable shielding masterbatch include the semiconductor shielding resin composition according to any one of claims 1-11.

13. The method for preparing the solid carbon-based cable shielding masterbatch according to claim 12, characterized in that, The preparation method includes: Step (1): Graphene, carbon nanotubes, acetylene black, propylene-based multiphase copolymer and surfactant are mixed evenly in an organic solvent to obtain a dispersion; Step (2): Centrifuge and filter the dispersion; Step (3): The solution obtained in step (2) is dried to obtain solid carbon-based cable shielding masterbatch.

14. A shielding material, characterized in that, The shielding material is obtained by extrusion of the solid carbon-based cable shielding masterbatch as described in claim 12 and a propylene-based multiphase copolymer.

15. The shielding material according to claim 14, characterized in that, The extrusion is carried out using a stretch rheological plasticizing extrusion equipment, with temperatures of 180-250℃ in each section, rotor speed of 50-120 rpm, feeder speed of 20-80 rpm, and length-to-diameter ratio of 30-40.

16. A cable, comprising a conductor, an inner shielding layer covering the conductor, an insulation layer covering the inner shielding layer, and an outer shielding layer covering the insulation layer, characterized in that, The material of the inner shielding layer and / or the outer shielding layer is the shielding material as described in claim 14 or 15.

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