CN108864527A - Semi-conductive screen layer material and preparation method for high-tension cable polypropylene insulation - Google Patents

Abstract

The invention discloses a semi-conductive shielding layer material used for polypropylene insulation of high-voltage cables, which comprises: 20-50 parts of polypropylene base material, 50-80 parts of elastomer base material, and 20-55 parts of conductive carbon black 0.5-2.5 parts of synergistic antioxidant, 0.01-3.0 parts of anti-copper agent and 0.5-10 parts of lubricating and dispersing agent; among them, 100 parts of polypropylene base material and elastomer base material, polypropylene base material is homopolypropylene It is a blend mixed with copolymerized polypropylene at a weight ratio of 0-10:1, and the melt index of homopolypropylene is 1.0-5.0g/10min, and the melt index of copolymerized polypropylene is 1.0-5.0g/10min. Its technical effects are: it has good mechanical properties, heat resistance, stable electrical conductivity, good copper resistance, non-crosslinking, fast extrusion line speed, environmental protection, and easy recycling. The invention also discloses a preparation method of the semi-conductive shielding layer material used for high-voltage cable polypropylene insulation.

Description

Semi-conductive shielding layer material for high-voltage cable polypropylene insulation and preparation method

technical field

The invention relates to a semi-conductive shielding layer material used for high-voltage cable polypropylene insulation and a preparation method.

Background technique

So far, the insulating layer material of high-voltage AC and DC power cables produced and manufactured in my country for commercial operation is basically cross-linked polyethylene. The insulating layer and the supporting semi-conductive shielding layer material must use cross-linked polyethylene that has been cross-linked and cured.

Insulation cannot be used alone without a semi-conductive shield in a high voltage cable. The semi-conductive shielding layer plays a very important role in the structure of high-voltage cables. The semi-conductive shielding layer is distributed on the inside and outside of the insulating layer, and is in close contact with the interface of the insulating layer. The interface is smooth and seamless, which can uniform the electric field and avoid free discharge caused by the gap. , Effectively ensure safe operation and cable life.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a semi-conductive shielding layer material and preparation method for high-voltage cable polypropylene insulation, which has good mechanical properties, heat resistance, stable electrical conductivity, and long-term operation The temperature is not lower than 110°C, low temperature resistance can reach -25°C and below, good copper resistance, non-crosslinking, fast extrusion line speed, green and environmentally friendly, easy to recycle.

A technical solution for achieving the above purpose is: a semi-conductive shielding layer material used for polypropylene insulation of high-voltage cables, which includes, in parts 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 anti-copper agent and 0.5-10 parts of lubricating and dispersing agent; a total of 100 parts of polypropylene base material and elastomer base material;

The polypropylene base material is a blend of homopolypropylene and copolymerized polypropylene at a ratio of 0 to 10:1, and the melt index of homopolypropylene is 1.0 to 5.0g/10min, and the melt index of copolymerized polypropylene is 1.0 to 5.0 g/10min.

Further, the elastomer base material is selected from at least one of:

Ethylene-octene copolymer with a melt index of 2.0-10g/10min and a density of 0.87g/ ^cm3 ;

Ethylene-butene copolymer with a melt index of 2.0-10g/10min and a density of 0.86-0.88g/ ^cm3 ;

Ethylene propylene rubber;

A granulated blend of polyethylene and granulated ethylene-propylene rubber, wherein the polyethylene is high-density polyethylene or low-density polyethylene with a melt index of 2.0 to 10 g/10min.

Still further, the molar percentage of ethylene in the ethylene-propylene rubber is 40-55%, the Mooney viscosity of the ethylene-propylene rubber is 20-40, and the molar percentage of the third elastomer is 0-4.7%.

Furthermore, the synergistic antioxidant includes a main antioxidant and an auxiliary antioxidant, the weight ratio of the main antioxidant and the auxiliary antioxidant is 1:0-1.0, and the main antioxidant is 4,4'-sulfur Substituting bis(6-tert-butyl-3-methylphenol), the auxiliary antioxidant is tris[2.4-di-tert-butylphenyl]phosphite.

Still further, the lubricating and dispersing agent is polyethylene wax or an organic amide lubricating and dispersing agent with a melting point greater than 100°C.

Still further, according to parts by weight, the semi-conductive shielding layer material for polypropylene insulation of high-voltage cables also contains no more than 1.0 parts of graphene.

Further, the anti-copper agent is selected from N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, N-salicylidene-N'-salicylichydrazide , at least one of mercaptobenzimidazole, 2-mercaptobenzimidazole, 2-mercaptobenzimidazole zinc salt, and 2-mercaptomethylbenzimidazole.

A technical solution to achieve the above purpose is: a method for preparing a semi-conductive shielding layer material used for high-voltage cable polypropylene insulation, which comprises polypropylene base material, elastomer base material, conductive carbon black, synergistic antioxidant, anti- After the copper agent and the lubricating dispersant are mixed, they are added to a continuous mixing unit for mixing, extruded and granulated to obtain pellets of semi-conductive shielding layer materials used for polypropylene insulation of high-voltage cables.

A technical solution to achieve the above purpose is: a method for preparing a semi-conductive shielding layer material used for polypropylene insulation of high-voltage cables, first adding elastomer base material, synergistic antioxidant, anti-copper agent and lubricating Mixing with a step speed regulating internal mixer, extruding and granulating to obtain pellets of the rubber mixture, then adding the rubber mixture, polypropylene base material and conductive carbon black into the continuous mixing unit for mixing, extruding and granulating to obtain Granules of semi-conductive shielding material for polypropylene insulation of high voltage cables.

Still further, the continuous mixing unit is selected from one of a mixing reciprocating machine, a co-rotating twin-screw extruder, and a continuous internal mixing unit with more than four combinations.

A technical scheme of semi-conductive shielding layer material used for high-voltage cable polypropylene insulation of the present invention is adopted, which includes: 20-50 parts of polypropylene base material, 50-80 parts of elastomer base material, conductive carbon 20-55 parts of black, 0.5-2.5 parts of synergistic antioxidant, 0.01-3.0 parts of anti-copper agent and 0.5-10 parts of lubricating and dispersing agent; 100 parts of polypropylene base material and elastomer base material in total, polypropylene base material is homogeneous Polypropylene and copolymerized polypropylene are mixed at a ratio of 0 to 10:1, and the melt index of homopolypropylene is 1.0 to 5.0g/10min, and the melt index of copolymerized polypropylene is 1.0 to 5.0g/10min. Its technical effects are: it has good mechanical properties, heat resistance, stable electrical conductivity, long-term working temperature is not lower than 110 ° C, low temperature resistance can reach -25 ° C and below, good copper resistance, non-crosslinking, extrusion The line speed is fast, green and environmentally friendly, and easy to recycle.

The technical scheme of the preparation method of a semi-conductive shielding layer material used for high-voltage cable polypropylene insulation of the present invention is adopted, and the polypropylene base material, elastomer base material, conductive carbon black, synergistic antioxidant, and anti-copper agent are used After being mixed with a lubricating dispersant, it is added to a continuous mixing unit for mixing, extruded and granulated to obtain pellets of semi-conductive shielding layer materials used for high-voltage cable polypropylene insulation. . It can also achieve the above-mentioned technical effects.

The technical scheme of the preparation method of a semi-conductive shielding layer material used for high-voltage cable polypropylene insulation is adopted. Firstly, the elastomer base material, synergistic antioxidant, anti-copper agent and lubricating dispersant are added into the stepless adjustment Mixing with a high-speed internal mixer, extruding and granulating to obtain pellets of the rubber mixture, and then adding the rubber mixture, polypropylene base material and conductive carbon black into the continuous mixing unit for mixing, extruding and granulating to obtain pellets for high-voltage cables Pellets of polypropylene insulating semi-conductive shielding material. It can also achieve the above-mentioned technical effects.

Detailed ways

In order to better understand the technical scheme of the present invention, the inventors of the present invention will describe in detail below through specific examples:

A semi-conductive shielding layer material used for polypropylene insulation of high-voltage cables of the present invention uses polypropylene and elastomers to be blended to form thermoplastic elastomers, which solves the shortcomings of polypropylene toughness and low-temperature brittleness and difficulty in filling conductive carbon black, A synergistic antioxidant with a high melting point is used to avoid the migration and precipitation of the antioxidant at working temperature. The semi-conductive shielding layer material used for high-voltage cable polypropylene insulation uses a lubricating dispersant to disperse the carbon black well and ensure that it does not Migrate towards the insulation layer, ie not migrate out of this semi-conductive shield material for polypropylene insulation of high voltage cables.

According to parts by weight, a semi-conductive shielding layer material used for high-voltage cable polypropylene insulation according to the present invention comprises 20-50 parts of polypropylene base material, 50-80 parts of elastomer base material, conductive carbon black 20 to 55 parts, 0 to 1.0 parts of graphene, 0.5 to 2.5 parts of synergistic antioxidant, 0.01 to 3.0 parts of anti-copper agent and 0.5 to 10 parts of lubricating and dispersing agent, including 100 parts of polypropylene base material and elastomer base material .

The polypropylene base material is a blend of homopolypropylene and copolymerized polypropylene at a ratio of 0 to 10:1, and the melt index of homopolypropylene is 1.0 to 5.0g/10min, and the melt index of copolymerized polypropylene is 1.0 to 5.0 g/10min.

The elastomer base material is selected from at least one of ethylene-octene copolymer, ethylene-butylene copolymer, ethylene-propylene rubber, and blends of polyethylene and ethylene-propylene rubber, and the melt index of the ethylene-octene copolymer is The melt index of the ethylene-butene copolymer is 2.0-10g/10min, and the density is ^{0.86-0.88g/cm 3 .}

The polyethylene is high-density polyethylene or low-density polyethylene, with a melt index of 2.0-10g/10min. The molar percentage of ethylene in the ethylene-propylene rubber is 40-55%, the Mooney viscosity is 20-40, and the molar percentage of the third monomer is 0-4.7%.

The synergistic antioxidant is the combination of 4,4'-thiobis(6-tert-butyl-3-methylphenol) primary antioxidant and tris[2.4-di-tert-butylphenyl]phosphite secondary antioxidant composition, or similar antioxidants, the weight ratio of the main antioxidant and the auxiliary antioxidant in the synergistic antioxidant is 1:0-1.0, the melting point of the synergistic antioxidant is relatively high, and the synergistic antioxidant can also be combined with rubber Mix with anti-aging agent to ensure that the synergistic anti-oxidant will not migrate and precipitate out of the semi-conductive shielding layer material used for high-voltage cable polypropylene insulation at the operating temperature of the cable.

The lubricating and dispersing agent is one or a combination of high-quality pure organic amide lubricating and dispersing agents or polyethylene wax, with a melting point greater than 100°C.

The conductive carbon black is the conductive carbon black prepared by the vapor phase deposition method or the oil furnace method, or a mixture of the above two carbon blacks.

Graphene is graphene treated with silane surface grafting.

The anti-copper agent is selected from N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, N-salicylidene-N'-salicylhydrazide, mercaptobenzo At least one of imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzimidazole zinc salt and 2-mercaptomethylbenzimidazole.

A semi-conductive shielding layer material used for high-voltage cable polypropylene insulation of the present invention can be made of polypropylene base material, elastomer base material, conductive carbon black, graphene, synergistic antioxidant, anti-copper agent and lubricating dispersant After direct mixing, use a continuous mixing unit, such as one of the mixing reciprocating machine and co-rotating twin-screw extruder, and obtain it directly by one-step method.

The mixing reciprocating machine includes a screw with a length-to-diameter ratio of 30:1, four rows of pins, and No. 1, No. 2 and No. 3 feeding hoppers, and No. 1, No. 2 and No. 3 feeding hoppers. Distributed along the axial direction of the screw, they are respectively located at the screw length-to-diameter ratios of 0:1, 8:1 and 16:1, the screw speed is 300rpm, and the total filling factor of the screw is 0.65-0.75.

Co-rotating twin-screw extruder, including screw and No. 1 feeding hopper, No. 2 feeding hopper and No. 3 feeding hopper, the ratio of screw length to diameter is 44:1, and No. The axial distribution of the screw is located at the screw length-to-diameter ratio of 0:1, 8:1 and 18:1, the screw speed is 400rpm, and the total filling factor of the screw is 0.6-0.7.

A kind of semi-conductive shielding layer material used for high-voltage cable polypropylene insulation of the present invention can first directly mix the elastomer base material graphene, synergistic antioxidant, anti-copper agent and lubricating dispersant, and then carry out stepless speed regulation banburying Mixing in the machine, and extruding and granulating to obtain rubber mixture granules, then mixing the rubber mixture granules with polypropylene base material and conductive carbon black, mixing in the continuous mixing unit, extruding and granulating to obtain The invention relates to a granular material of a semi-conductive shielding layer material used for high-voltage cable polypropylene insulation.

The granulation of a semi-conductive shielding layer material used for high-voltage cable polypropylene insulation is extruded by a melt pump, ultra-fine filtration, high-level purification, and fully automatic control process. The main process parameters and technical requirements are: Mixed The refining temperature is 150-200°C, the rotor or screw speed is 50-400rpm, the viscoelastic fluid passes through a 200-400 mesh filter before extrusion, the cooling medium for cooling the rotor or screw is deionized water, and the rotor or screw is blown The cold and air purification grade is not less than 10000, and the moisture content of the pellets after drying is below 200ppm.

Illustrate below by specific embodiment:

Example 1:

The semi-conductive shielding layer material used for high-voltage cable polypropylene insulation of the present embodiment includes by weight parts:

10 parts of homopolymerized polypropylene whose grade is T30 and 20 parts of copolymerized polypropylene whose grade is M180 form 30 parts of polypropylene base material.

35 parts of LD608 low-density polyethylene and 35 parts of Dow 8200 ethylene-octene copolymer form 70 parts of elastomer base.

40 parts of trade marks are the conductive carbon black of NJF.

0.2 part of 4,4'-thiobis(6-tert-butyl-3-methylphenol) as the main antioxidant and 0.1 part of tris[2.4-di-tert-butylphenyl] as secondary antioxidant Phosphate esters form 0.3 parts of synergistic antioxidants, and the weight ratio of main antioxidants and synergistic antioxidants in synergistic antioxidants is 1 to 0.5.

0.1 part of N-salicylidene-N'-salicylhydrazide and 0.1 part of 2-mercaptobenzimidazole zinc salt form 0.3 part of anticopper agent.

0.5 parts of ethylene bisoleic acid amide as a lubricating dispersant.

Its preparation is carried out on a single-screw mixing and reciprocating machine, which belongs to a one-step method and includes the following steps:

No. 1 feeding hopper, add polypropylene base material, elastomer base material, synergistic antioxidant, anti-copper agent, lubricating dispersant, No. 3 feeding hopper add 1/3 weight of conductive carbon black, No. Two-thirds of the weight of conductive carbon black is mixed to obtain a viscoelastic fluid. The temperature distribution in the single-screw mixing reciprocating machine is 120°C-150°C-170°C-190°C-190°C, and the screw speed is 200rpm; the viscoelastic The fluid passes through a 400-mesh filter screen and is extruded and granulated to obtain pellets of semi-conductive shielding layer materials used for polypropylene insulation of high-voltage cables; the pellets are air-dried and packaged.

Example 2

The semi-conductive shielding layer material used for high-voltage cable polypropylene insulation of the present embodiment includes by weight parts:

50 parts of copolymerized polypropylene of grade 800E form 50 parts of polypropylene base material.

20 parts of grade 5000s high density polyethylene and 30 parts of grade 8200 ethylene-octene copolymer to form 50 parts of elastomer base.

20 parts of trade marks are the conductive carbon black of NJF.

0.5 parts of 4,4'-thiobis(6-tert-butyl-3-methylphenol), as a synergistic antioxidant.

0.5 parts of N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine as an anticopper agent.

2.0 parts of polyethylene wax as a lubricating dispersant.

Its preparation is carried out on a single-screw mixing and reciprocating machine, which belongs to a one-step method and includes the following steps:

No. 1 feeding hopper, add polypropylene base material, elastomer base material, synergistic antioxidant, anti-copper agent, lubricating and dispersing agent, No. 2 feeding hopper adds conductive carbon black, kneading to obtain viscoelastic fluid, single-screw kneading and reciprocating The temperature distribution inside the machine is 150°C-190°C-190°C-200°C-200°C-200°C-190°C-180°C, the screw speed is 400rpm; the viscoelastic fluid is passed through a 400-mesh filter; the viscoelastic fluid is Extrusion and granulation to obtain pellets of semi-conductive shielding material for polypropylene insulation of high-voltage cables; air-drying and packaging of the pellets.

Example 3

The semi-conductive shielding layer material used for high-voltage cables and polypropylene insulation of high-voltage cables in this embodiment includes according to parts by weight:

40 parts are the copolymerized polypropylene of M180 as the trade mark of polypropylene base material.

10 parts of grades are 2200J high-density polyethylene, 20 parts of grades are ethylene-propylene rubber of EP4045, and 30 parts of grades are ethylene-butylene copolymers of DF740 to form 60 parts of elastomer base material.

1.0 parts of graphene whose trade mark is CNTS-010-0, the particle diameter of graphene is 0.3～8nm.

40 parts of trade marks are the conductive carbon black of NJF.

1.0 part of 4,4'-thiobis(6-tert-butyl-3-methylphenol) as the main antioxidant, 0.5 part of tris[2.4-di-tert-butylphenyl] as auxiliary antioxidant Phosphate esters form 1.5 parts of synergistic antioxidants, and the weight ratio of primary antioxidants and auxiliary antioxidants in synergistic antioxidants is 1 to 0.5.

0.5 parts of 2-mercaptobenzimidazole as an anticopper agent.

0.5 parts of ethylene bisoleic acid amide as a lubricating dispersant.

Its preparation is a two-step process:

First, high-density polyethylene, ethylene-propylene rubber, graphene, synergistic antioxidant, anti-copper agent and lubricating dispersant are added to the stepless speed-regulating internal mixer for mixing, and the speed of the stepless speed-regulating internal mixer rotor is 70rpm , the mixing temperature was 150°C, followed by granulation with a single-screw extruder to obtain uniformly dispersed rubber mixture pellets.

Then add the rubber mixture pellets, polypropylene base material, ethylene-butene copolymer and conductive carbon black into the single-screw mixing reciprocator and mix to obtain a viscoelastic fluid. The No. 1 feeding hopper is filled with rubber mixture pellets, poly Propylene base material and ethylene-butene copolymer, two-thirds of the weight of conductive carbon black is added to No. 2 feeding hopper, and one-third of the weight of conductive carbon black is added to No. 3 feeding hopper. 150°C-190°C-190°C-200°C-200°C-200°C-190°C-180°C, the screw speed of the single-screw mixing and reciprocating machine is 300rpm, and the viscoelastic fluid is passed through a 400-mesh filter; Pelletization is carried out to obtain semi-conductive shielding material for polypropylene insulation of high voltage cables; the pellets are air-dried and packaged.

Example 4

The semi-conductive shielding layer material used for high-voltage cable polypropylene insulation in this embodiment includes according to parts by weight:

20 parts of grades are copolymerized polypropylene of M180 to form a polypropylene base material.

20 parts of LD608 low-density polyethylene, 30 parts of EP4045 ethylene-propylene rubber, and 30 parts of DF740 ethylene-butylene copolymer form 80 parts of elastomer base material.

55 parts of trade marks are the conductive carbon black of NJF.

2.0 parts of 4,4'-thiobis(6-tert-butyl-3-methylphenol), as a synergistic antioxidant.

0.5 parts of 2-mercaptobenzimidazole zinc salt as an anticopper agent.

3.0 parts of ethylene bisoleic acid amide and 7.0 parts of polyethylene wax form 10 parts of lubricating dispersant.

Its preparation is a two-step process:

First, low-density polyethylene, ethylene-propylene rubber, synergistic antioxidant, anti-copper agent and lubricating dispersant are added to the stepless speed-regulating internal mixer for mixing. 150°C, followed by granulation with a single-screw extruder to obtain uniformly dispersed rubber mixture granules.

Then add the rubber mixture pellets, polypropylene base material, ethylene-butene copolymer and conductive carbon black into the single-screw mixing reciprocator and mix to obtain a viscoelastic fluid. The No. 1 feeding hopper is filled with rubber mixture pellets, poly Propylene base material and ethylene-butene copolymer, three-quarters of the weight of conductive carbon black was added to the No. 2 feeding hopper, and one-quarter of the weight of conductive carbon black was added to the No. 3 feeding hopper. The temperature distribution of the single-screw mixing and reciprocating machine 150°C-190°C-190°C-200°C-200°C-200°C-190°C-180°C, the screw speed of the single-screw mixing and reciprocating machine is 200rpm, and the viscoelastic fluid is passed through a 200-mesh filter; for viscoelastic fluid Pelletizing is carried out to obtain pellets of semi-conductive shielding material for polypropylene insulation of high voltage cables; the pellets are air-dried and packaged.

Example 5

The semi-conductive shielding layer material used for high-voltage cable polypropylene insulation in this embodiment includes according to parts by weight:

10 parts of grades are T30 homopolypropylene and 40 parts of grades are 800E copolymerized polypropylene to form 50 parts of polypropylene base material.

20 parts of EPT4045 ethylene propylene rubber and 30 parts of DF740 ethylene-butylene copolymer form 50 parts of elastomer base material.

30 parts of trade marks are the conductive carbon black of NJF.

1.5 parts of 4,4'-thiobis(6-tert-butyl-3-methylphenol) as the main antioxidant and 0.5 parts of tris[2.4-di-tert-butylphenyl]phenylene as the auxiliary antioxidant Phosphate ester, forming 2.0 parts of main antioxidant synergistic antioxidant, the weight ratio of main antioxidant and auxiliary antioxidant in synergistic antioxidant is 1 to 0.33.

0.1 part of 2-mercaptobenzimidazole zinc salt as an anticopper agent.

0.3 parts of ethylene bisoleic acid amide and 5 parts of polyethylene wax form 5.3 parts of lubricating dispersant.

Its preparation is a two-step process:

First, the elastomer base material, synergistic antioxidant, anti-copper agent and lubricating and dispersing agent were added to the stepless speed regulating internal mixer for mixing. The speed of the stepless speed regulating internal mixer rotor was 70rpm, and the mixing temperature was 150°C. Then granulate with a single-screw extruder to obtain uniformly dispersed rubber mixture granules.

Then add the rubber mixture pellets, polypropylene base material and conductive carbon black into the co-rotating twin-screw extruder and mix to obtain a viscoelastic fluid. The rubber mixture pellets, polypropylene base material and conductive carbon black are all fed from No. 1 The hopper is fed into the co-rotating twin-screw extruder. The temperature distribution of the co-rotating twin-screw extruder is 150°C-190°C-190°C-200°C-200°C-200°C-200°C-190°C. The rotating speed 300rpm of the screw rod of exiting machine, viscoelastic fluid is passed through 300 purpose filter screens; Viscoelastic fluid is carried out granulation, obtains the pellet of the semi-conductive shielding layer material that is used for high-voltage cable polypropylene insulation; The pellet is carried out air drying and Package.

Example 6

The semi-conductive shielding material used for high-voltage cable polypropylene insulation in this embodiment includes:

10 parts of T30 homopolypropylene and 20 parts of 800E copolymerized polypropylene form 30 parts of polypropylene base material.

20 parts of high-density polyethylene of grade 2200J and 50 parts of ethylene-octene copolymer of grade 8200 constitute 70 parts of elastomer base material.

40 parts of trade marks are the conductive carbon black of NJF.

2.5 parts of 4,4'-thiobis(6-tert-butyl-3-methylphenol), as synergistic antioxidant.

0.1 part of mercaptomethylbenzimidazole as an anticopper agent.

3.0 parts of ethylene bisoleic acid amide hydrazine and 5.0 parts of polyethylene wax form 8.0 parts of lubricating and dispersing agent.

Its preparation is a one-step method:

Through automatic weighing, add polypropylene base material, elastomer base material, synergistic antioxidant, anti-copper agent and mercaptomethylbenzimidazole into the No. The conductive carbon black is added into the No. 2 feeding hopper of the single-screw mixing compounder, and one-third of the weight of conductive carbon black is added into the No. Mixing to obtain viscoelastic fluid, the temperature distribution of the single-screw mixing to the compound mixer is 150°C-190°C-190°C-200°C-200°C-200°C-190°C-180°C, the single-screw mixing to the screw of the compound The rotation speed of the viscoelastic fluid is 300rpm, and the viscoelastic fluid is passed through a 300-mesh filter screen; the viscoelastic fluid is granulated to obtain pellets of semi-conductive shielding layer materials used for polypropylene insulation of high-voltage cables; the pellets are air-dried and packaged.

The properties of the semi-conductive shielding layer materials used for high-voltage cable polypropylene insulation in Examples 1 to 6 were tested, as shown in Table 1.

Among them, the thermal deformation test adopts the method specified in GB/T8815. The diameter or side length of the test piece is 12mm, the thickness is 1.25mm, the diameter of the cylindrical indenter is 3.15mm, and the load is 3.50N. The copper test is an aging test with a copper piece clamped on one side of the test piece, that is, it will not be brittle for 10 days at 135°C.

Table 1 Embodiment 1～6 performance comparison table

A semi-conductive shielding layer material used for high-voltage cable polypropylene insulation of the present invention does not need to be cross-linked, as long as it is plasticized and extruded, it can produce high-voltage cables, greatly improves the extrusion line speed, has no gaseous by-products, and does not require Subsequent degassing treatment process, at the same time, does not cause environmental pollution, no scorched matter, almost no need to stop frequently to clean the machine, and has a higher working temperature than XLPE cables, which is conducive to improving the current carrying capacity of cables and improving the performance of cables. Temperature grade, and reduce the conductor cross-section, because it is a non-cured plastic material, green and environmentally friendly, recyclable.

A semi-conductive shielding layer material used for polypropylene insulation of high-voltage cables of the present invention is used as the inner and outer layer shielding of the insulating layer, and is co-extruded with polypropylene to form a three-layer insulating layer, which matches the performance of the insulating layer and has good performance. Excellent conductive stability, good rheological properties, green and environmentally friendly, recyclable, heat resistance and temperature level are equivalent to insulation layer made of polypropylene, heat distortion temperature is greater than 130 ° C, can be used for 220kV and below high-voltage polypropylene cables Semi-conductive shielding layer material, the operating temperature is not lower than 110°C, and the low temperature resistance can reach -25°C and below.

A semi-conductive shielding layer material used for high-voltage cable polypropylene insulation of the present invention solves the shortcomings of poor toughness of polypropylene, brittleness at low temperature and difficulty in dispersing filled conductive carbon black, and adopts a synergistic antioxidant system with a high melting point. To avoid the migration and precipitation of the synergistic antioxidant at working temperature, use a suitable lubricating and dispersing agent to disperse the conductive carbon black well and ensure that it does not migrate to the insulating layer.

Those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present invention, rather than to limit the present invention, as long as within the spirit of the present invention, changes to the above embodiments, Modifications are intended to fall within the scope of the claims of the present invention.

Claims (10)

1. A semi-conductive shielding layer material for high-voltage cable polypropylene insulation, characterized in that: according to parts by weight, it comprises: 20-50 parts of polypropylene base material, 50-80 parts of elastomer base material, 20 parts of conductive carbon black ～55 parts, 0.5～2.5 parts of synergistic antioxidant, 0.01～3.0 parts of anti-copper agent and 0.5～10 parts of lubricating and dispersing agent, including 100 parts of polypropylene base material and elastomer base material; The polypropylene base material is a blend of homopolypropylene and copolymerized polypropylene at a ratio of 0 to 10:1, and the melt index of homopolypropylene is 1.0 to 5.0g/10min, and the melt index of copolymerized polypropylene is 1.0 to 5.0 g/10min. 2. A kind of semi-conductive shielding layer material for high-voltage cable polypropylene insulation according to claim 1, characterized in that: The elastomer base material is selected from at least one of: Ethylene-octene copolymer with a melt index of 2.0-10g/10min and a density of 0.87g/ ^cm3 ; Ethylene-butene copolymer with a melt index of 2.0-10g/10min and a density of 0.86-0.88g/ ^cm3 ; Ethylene propylene rubber; A granulated blend of polyethylene and granulated ethylene-propylene rubber, wherein the polyethylene is high-density polyethylene or low-density polyethylene with a melt index of 2.0 to 10 g/10min. 3. A semi-conductive shield material for high-voltage cable polypropylene insulation according to claim 2, characterized in that: the molar percentage of ethylene in the ethylene-propylene rubber is 40 to 55%, and the ethylene-propylene rubber The Mooney viscosity is 20-40, and the molar percentage of the third elastomer is 0-4.7%. 4. A semi-conductive shielding layer material for high-voltage cable polypropylene insulation according to claim 2, characterized in that: synergistic antioxidants include primary antioxidants and auxiliary antioxidants, primary antioxidants and auxiliary antioxidants The weight ratio of antioxidants is 1:0~1.0, the main antioxidant is 4,4'-thiobis(6-tert-butyl-3-methylphenol), and the auxiliary antioxidant is three [2.4- Di-tert-butylphenyl]phosphite. 5. A semi-conductive shielding layer material for polypropylene insulation of high-voltage cables according to claim 2, wherein the lubricating and dispersing agent is polyethylene wax or an organic amide-based lubricating and dispersing agent with a melting point greater than 100°C. 6. A semi-conductive shielding layer material for high-voltage cable polypropylene insulation according to claim 2, characterized in that: in parts by weight, it also contains no more than 1.0 parts of graphene. 7. A semi-conductive shielding layer material for high-voltage cable polypropylene insulation according to claim 2, characterized in that: the anti-copper agent is selected from N, N'-bis[3-(3,5-di-tert-butyl -4-Hydroxyphenyl)propionyl]hydrazine, N-salicylidene-N'-salicylhydrazide, mercaptobenzimidazole, 2-mercaptobenzimidazole, 2-mercaptobenzimidazole zinc salt, 2-mercapto At least one of methylbenzimidazoles. 8. A preparation method for a semi-conductive shielding layer material used for high-voltage cable polypropylene insulation, characterized in that: polypropylene base material, elastomer base material, conductive carbon black, synergistic antioxidant, anti-copper agent and lubricating After the dispersant is mixed, it is added to a continuous mixing unit for mixing, extruded and granulated to obtain pellets of semi-conductive shielding layer materials used for high-voltage cable polypropylene insulation. 9. A preparation method for a semi-conductive shielding layer material used for high-voltage cable polypropylene insulation, characterized in that: firstly, adding elastomer base material, synergistic antioxidant, anti-copper agent and lubricating dispersant to the stepless speed-regulating compact Mixing in the mill, extruding and granulating to obtain pellets of the rubber mixture, then adding the rubber mixture, polypropylene base material and conductive carbon black into the continuous mixing unit for mixing, extruding and granulating to obtain polypropylene for high-voltage cables Pellets of insulating semi-conductive shielding material. 10. A method for preparing a semi-conductive shielding layer material for high-voltage cable polypropylene insulation according to claim 9, characterized in that: the continuous mixing unit is selected from mixing reciprocating machines, co-rotating twin-screw extruders It is one of the continuous mixer units with more than four combinations.