CN114783658A - Polypropylene insulation wire core and preparation method thereof - Google Patents
Polypropylene insulation wire core and preparation method thereof Download PDFInfo
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- CN114783658A CN114783658A CN202210610634.3A CN202210610634A CN114783658A CN 114783658 A CN114783658 A CN 114783658A CN 202210610634 A CN202210610634 A CN 202210610634A CN 114783658 A CN114783658 A CN 114783658A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B7/00—Insulated conductors or cables characterised by their form
- H01B7/02—Disposition of insulation
- H01B7/0275—Disposition of insulation comprising one or more extruded layers of insulation
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
- H01B13/06—Insulating conductors or cables
- H01B13/14—Insulating conductors or cables by extrusion
- H01B13/141—Insulating conductors or cables by extrusion of two or more insulating layers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
- H01B13/22—Sheathing; Armouring; Screening; Applying other protective layers
- H01B13/24—Sheathing; Armouring; Screening; Applying other protective layers by extrusion
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
- H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
- H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
- H01B3/44—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B7/00—Insulated conductors or cables characterised by their form
- H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
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Abstract
The invention discloses a polypropylene insulation wire core which comprises a conductor, a semi-conductive conductor shielding layer, an insulation layer and a semi-conductive insulation shielding layer from inside to outside, wherein the semi-conductive conductor shielding layer is composed of polypropylene semi-conductive conductor shielding materials, the insulation layer is composed of polypropylene insulation materials, and the semi-conductive insulation shielding layer is composed of polypropylene semi-conductive insulation shielding materials. The invention also provides a preparation method of the polypropylene insulated wire core. The polypropylene material is used as the insulating layer, so that the voltage resistance level is high, the long-term working temperature can reach 105 ℃, the current-carrying capacity of the cable can be greatly improved, and the system loss can be reduced; the production process of the polypropylene insulating and shielding material is simple, crosslinking is not needed, and the production process requirement and the energy requirement are greatly reduced; the polypropylene material is a thermoplastic material and can be recycled, degraded and reused. The invention adopts three-layer co-extrusion production to ensure the cleanliness, reduce impurities and air holes in the wire core and ensure the effectiveness of long-term operation of the wire core insulation.
Description
Technical Field
The invention relates to the technical field of cables, in particular to a polypropylene insulated wire core and a preparation method thereof.
Background
The traditional XLPE insulated cable has been applied for many years, and has a plurality of problems, such as the need of special vulcanization pipelines for crosslinking in the processing process, expensive equipment cost and high installation cost; the production process is complex, pre-crosslinked particles are easy to generate in the insulating material, and the control difficulty of the crosslinking degree is high; water branches and electric branches are easy to generate after long-term use in a humid environment, and the service life is 15-20 years generally.
With the trend of people toward good life, the national requirement on environmental protection is higher and higher, the problem of material pollution caused by replacement of the cable after the cable reaches the service life or in the process is considered, and the XLPE is low in decomposition speed and cannot be recycled at industrial level basically. Although more and more TR-XLPE insulated cables are adopted at present, the water tree resistance of the cables is enhanced, and the service life of the cables is prolonged, but the problem of recycling and reprocessing of materials cannot be solved. The polypropylene is environment-friendly and recyclable, does not need cross-linking, has lower material cost and production equipment cost investment than XLPE, reduces energy consumption in production, shortens production period, can greatly reduce carbon emission, but has larger shrinkage and can not be well applied to insulated cables.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is the defect of the existing insulated XLPE cable, so that the polypropylene insulated wire core and the preparation method thereof are provided.
Therefore, the invention adopts the following technical scheme:
the invention provides a polypropylene insulated wire core which comprises a conductor, a semi-conductive conductor shielding layer, an insulating layer and a semi-conductive insulated shielding layer from inside to outside, wherein the semi-conductive conductor shielding layer consists of polypropylene semi-conductive conductor shielding materials, the insulating layer consists of polypropylene insulating materials, and the semi-conductive insulated shielding layer consists of polypropylene semi-conductive insulated shielding materials.
Further, it is characterized in that the material is,
the conductor is a second type of twisted compacted copper or aluminum conductor, and the direct current resistance and the number of monofilaments of the conductor meet the requirements of IEC 60228;
the polypropylene-based semiconductive conductor shielding material is thermoplastic and can not be peeled from a polypropylene insulating layer, and after the polypropylene-based semiconductive conductor shielding material is extruded into a cable, all performances of the cable meet the technical requirements for semiconductive conductor shielding in IEC 60502-2 standard;
the raw materials of the polypropylene insulating material comprise polypropylene, a thermoplastic elastomer and a processing aid; the polypropylene insulating material is thermoplastic, and after being extruded into a cable, various performances meet the technical requirements of HPTE insulation in the NEN-HD 620S2 standard;
the polypropylene-based semiconductive insulation shielding material comprises polypropylene, a thermoplastic elastomer, carbon black and a processing aid, is thermoplastic, and meets the technical requirements of IEC 60502-2 standard on semiconductive insulation shielding after being extruded into a cable.
The polypropylene-based semiconductive insulation shielding material is a strippable polypropylene semiconductive insulation shielding material or a non-strippable polypropylene semiconductive insulation shielding material.
Preferably, the first and second liquid crystal display panels are,
the polypropylene-based semiconductive conductor shielding material and the non-strippable polypropylene semiconductive insulation shielding material are the same in raw material, and comprise the following raw materials in parts by weight:
the polypropylene insulating material comprises the following raw materials in parts by weight:
the strippable polypropylene-based semiconductive insulation shielding material comprises the following raw materials in parts by weight:
further, the air conditioner is provided with a fan,
the diameter of the conductor is from 6.0mm to 34.0 mm;
the thickness of the shielding layer of the semiconductor conductor is 0.50mm-1.40 mm;
the nominal thickness of the insulating layer is 2.50mm-10.5 mm;
the thickness of the semiconductive insulating shielding layer is 0.50mm-1.20 mm.
The invention also provides a preparation method of the polypropylene insulated wire core, which comprises the following steps:
s1: selecting a polypropylene-based semiconductive conductor shielding material, a polypropylene insulating material and a polypropylene-based semiconductive insulating shielding material;
s2: covering the conductor with polypropylene-based semiconductive conductor shielding material to form a semiconductive conductor shielding layer;
s3: coating polypropylene insulating material on the shielding layer of the semi-conductive conductor
S4: covering the polypropylene-based semiconductive insulation shielding material on the insulation layer to form a semiconductive insulation shielding layer;
s5: and cooling to obtain the polypropylene insulated wire core.
Further, the coating in steps S2, S3, and S4 is a three-layer co-extrusion, and the polypropylene-based semiconductive conductor shielding material, the polypropylene insulating material, and the polypropylene-based semiconductive insulating shielding material are sequentially coated on the conductor to form a semiconductive conductor shielding layer, an insulating layer, and a semiconductive insulating shielding layer.
Preferably, in the three-layer co-extrusion,
setting the temperature of a polypropylene semiconductive conductor shielding material extruder to be 80-210 ℃ from the feeding direction to the discharging direction;
setting the temperature of the polypropylene insulating material extruder to be 80-210 ℃ from the feeding direction to the discharging direction;
from feeding to ejection of compact direction, the polypropylene semi-conductive insulation shielding extruder temperature sets for: 80-220 ℃;
the temperature of the machine neck section of the polypropylene semi-conductive conductor shielding material extruder is 190-210 ℃;
the temperature of the machine neck section of the polypropylene insulating material extruder is 195-240 ℃;
the temperature of the machine neck section of the polypropylene semi-conductive insulating shielding material extruder is 190-220 ℃; wherein the temperature of the extruder for the strippable polypropylene semiconductive insulation shielding material is set to be 100-220 ℃; the temperature of an extruder for the non-strippable polypropylene semi-conductive insulation shielding material is set to be 80-200 ℃;
the polypropylene semi-conductive conductor shielding material extruder, the polypropylene insulating material extruder and the polypropylene semi-conductive insulating shielding material extruder use a three-layer co-extruder head, and the temperature of the extruder head is 215-255 ℃.
In step S5, the cooling is performed by water bath cooling with water temperature of 10-40 deg.C
After the insulating wire core is extruded out, the insulating wire core directly enters a cooling water pipe after passing through an online lateral deviation instrument, and the cooling water pipe provides circulating cooling water to ensure that the water temperature is in a controllable range. In addition, according to the length of the cooling water pipe, the production speed of the insulation wire cores of different models and specifications is adjusted, so that the polypropylene insulation wire cores are fully cooled after being discharged from the cooling water pipe, and no shrinkage deformation occurs.
The three-layer co-extrusion system used in the present application is divided into: the device comprises a pay-off rack, a wire storage device, 3 plastic extruders with independent feeding systems, a three-layer co-extrusion machine head with an independent heating system, an online lateral deviation system, a cooling system, a wire twisting machine, a wire take-up device and a traction system.
Of these, 3 extruders equipped with independent feeding systems were used for the extrusion of polypropylene-based conductor shield, polypropylene insulation, and polypropylene-based insulation shield, respectively. The special screw for polypropylene materials is adopted, and the size combination of the screw is three, which are respectively: 60+150+90, 100+175+100, 100+200+ 100; the screw rod of the device is influenced by the performance of the polypropylene material, so that the polypropylene is insulated, and the better glue discharging stability is achieved. Compared with a medium-voltage XLPE insulated cable extruder, the material cylinders of the 3 polypropylene extruders are made of materials capable of tolerating higher temperature, and the heating system is matched, so that the temperature of the extruder body can be adjusted and stabilized at 70-280 ℃.
The three-layer co-extrusion machine head with the independent heating system realizes the heating from the machine neck to the machine head part through 2 high-temperature die temperature meters, and the highest heating temperature can reach 300 ℃.
The cooling system is used for cooling the thermal-state insulated wire core after the three layers of co-extrusion. The pay-off rack, the wire storage device, the on-line lateral deviation system, the wire twisting device, the wire collecting device and the traction system are basically consistent with a catenary chemical cross-linking production line (CCV) for XLPE insulation extrusion.
The technical scheme of the invention has the following advantages:
(1) in the invention, the polypropylene material is used as insulation, the voltage resistance level is high, the long-term working temperature can reach 105 ℃, the current-carrying capacity of the cable can be greatly improved, and the system loss can be reduced; in addition, the production process of the polypropylene insulating and shielding material is simple, crosslinking is not needed, pre-crosslinked particles do not exist in the process of parking reproduction, the requirements of the production process and the energy source are greatly reduced, and the processing cost is low; the polypropylene resin has rich yield and generally lower cost than the polyethylene resin. Meanwhile, the polypropylene material is a thermoplastic material, can be recycled, degraded and reused, and has the characteristic of environmental protection.
(2) In the invention, the conductor shielding layer, the insulating layer and the insulating shielding layer of the wire core are produced in a three-layer co-extrusion mode. The three-layer co-extrusion production ensures the cleanliness of cable insulation, reduces impurities and air holes in the insulation and ensures the effectiveness of the cable insulation in long-term operation.
(3) The invention uses polypropylene material, does not need cross-linking, avoids the condition that the XLPE wire core needs to continuously provide a cross-linking environment at 300-450 ℃, greatly reduces the energy requirement, can directly transfer the sequence after the production of the product, does not need the degassing process of the XLPE insulated wire core, obviously improves the production efficiency, and is particularly suitable for large-length production;
(4) the invention limits the temperature of different machine body positions during extrusion, and ensures that the polypropylene material is stably and uniformly extruded under the high-temperature extrusion condition, namely the stability of the hot outer diameter.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 shows a polypropylene insulated wire core according to example 1 of the present invention.
Reference numerals are as follows:
1-a conductor; 2-a semiconducting conductor shield layer; 3-an insulating layer; 4-semiconductive insulating shield layer.
Detailed Description
The following examples are provided to better understand the present invention, not to limit the best mode, and not to limit the content and protection scope of the present invention, and any product that is the same or similar to the present invention and is obtained by combining the present invention with other features of the prior art and the present invention falls within the protection scope of the present invention.
The examples do not indicate specific experimental procedures or conditions, and can be performed according to the procedures or conditions of the conventional experimental procedures described in the literature in the field. The reagents or instruments used are conventional reagent products which are commercially available, and manufacturers are not indicated.
Example 1
The present embodiment provides a polypropylene insulated wire core, which has a structure as shown in fig. 1, and includes, in order from inside to outside, a conductor 1, a semiconductive conductor shielding layer 2, an insulating layer 3, and a semiconductive insulation shielding layer 4.
The specific manufacturing method is as follows:
(1) the semi-conductive conductor shielding layer, the insulating layer and the semi-conductive insulating shielding layer are sequentially coated on the conductor through three layers of co-extrusion.
Wherein: the nominal thickness of the conductor shield of the semiconductive conductor shield layer is 0.8mm, the average thickness is 0.60mm, and the thickness of the thinnest point is 0.50 mm; the semiconductive conductor shielding layer material is selected from a semiconductive shielding material PBB-B9102 developed by Jiangsu Shanghai Cable group company Limited.
The insulation nominal thickness of the insulation layer is 4.5mm, the average thickness is 4.50mm, and the thickness of the thinnest point is 3.95 mm; the insulating material is polypropylene insulating material PP-JC-0801 developed by Jiangsu Shanghai Cable group Limited.
The nominal thickness of the insulation shield of the semiconductive insulation shield layer is 0.8mm, the average thickness is 0.60mm, and the thinnest point thickness is 0.50 mm. The semiconductive insulating shielding layer material is a semiconductive shielding material PBB-B9102 developed by Jiangsu Shanghai Cable group Limited.
The three-layer co-extrusion process has the following requirements:
from feeding to ejection of compact direction, three-layer is crowded fuselage temperature control altogether as follows:
the polypropylene-based semiconductive conductor shielding material PBB-B9102 is extruded in a phi 60 extruder, and the temperatures of a first zone to a fourth zone of the extruder are as follows in sequence: 100 ℃/140 ℃/190 ℃/190 ℃;
extruding a polypropylene insulating material PP-JC-0801 in a phi 150 extruder, wherein the temperatures of a first zone to a sixth zone of the extruder are as follows: 80 ℃/130 ℃/175 ℃/190 ℃/195 ℃;
extruding the non-peelable polypropylene-based semiconductive insulation shielding material PBB-B9102 in a phi 90 extruder, wherein the temperatures of a first zone to a fifth zone of the extruder are as follows: 100 ℃/140 ℃/190 ℃/190 ℃/190 ℃;
wherein: the first zone is a feeding section, the second zone and the third zone are plasticizing sections, and the fourth zone and the following zones are homogenizing sections;
a polypropylene-based semiconductive conductor shielding extruder (phi 60) uses a filter screen with 20 meshes, 80 meshes and 20 meshes, and the temperature of a machine neck section is 190 ℃;
a polypropylene insulating extruder (phi 150) uses a sieve of 80 meshes, 200 meshes, 80 meshes and 20 meshes, and the temperature of a machine neck section is 195 ℃;
a non-strippable polypropylene semi-conductive insulation shielding extruder (phi 90) uses a filter screen with 20 meshes, 80 meshes and 20 meshes, and the temperature of a neck section of the extruder is 190 ℃;
the polypropylene-based semiconductive conductor shielding extruder (phi 60), the polypropylene insulation extruder (phi 150) and the non-strippable polypropylene semiconductive insulation shielding extruder (phi 90) use a three-layer co-extrusion machine head, the machine head is heated by an oil-thermal mold temperature instrument, and the temperature is set to 225 ℃/225 ℃.
All temperature settings described above allow a deviation of ± 5 ℃.
(2) And directly cooling by adopting cold water after extrusion, wherein the temperature of the cooling water is 15 ℃, and obtaining the polypropylene insulated wire core.
The obtained polypropylene insulated wire core is detected, and in the embodiment, the performance parameters of the cable core are as follows:
1. routine alternating voltage test: 40kV and 15min power frequency alternating current voltage is applied between the conductor and the metal shield according to the NEN-HD 620S2 standard, and the cable is not broken down.
The project is higher than the requirement of national standard GB/T12706.2 for 30.5kV and 5 min.
2. Partial discharge test: applying 1.73U between conductor and metal shield0There was no measurable discharge exceeding the stated sensitivity (5pC or better).
3. Bending test and subsequent partial discharge test:
the diameter of the bending test cylinder satisfies:
20(D + D) +/-5% single-core non-armoured
Bending for three times; subsequent partial discharge experiments, no measurable discharge exceeding the stated sensitivity (5pC or better). (D-diameter of bent core, D-diameter of cable)
4. Measurement of tan δ at room temperature: AC voltage U0The tan delta measurement satisfies not more than 20X 10-4。
5. Heating cycle test: the heating cycle is continued for at least 8h, and during each heating process, the conductor temperature is maintained at 5-10 deg.C for at least 2h, and then naturally cooled in air for at least 3h to make the conductor temperature not exceed 10 deg.C. The cycle was repeated 20 times. After cycle 20, a partial discharge test was performed without any measurable discharge exceeding the stated sensitivity (5pC or better).
When the sample is subjected to thermal cycling, the tan delta of the sample is measured at least once when the temperature of the sample exceeds the maximum operating temperature (5-10) DEG C of a conductor according to the regulation of GB/T3048.11-2007. At an alternating voltage U0The tan delta measurement satisfies not more than 40X 10-4。
After the 20 th cycle, tan. delta. was measured at room temperature as specified in GB/T3048.11-2007. AC voltage U0The tan delta measured value satisfies not more than 20X 10-4。
6. Impulse voltage test and subsequent power frequency voltage test: the temperature of the conductor exceeds the maximum operation temperature (5-10) DEG C of the conductor, the impulse voltage meeting the GB/T12706 requirement and the positive polarity impulse voltage for 10 times are applied, and the cable is not broken down; after the surge voltage test, a routine ac voltage test was performed without breakdown of the insulation.
7. 24h voltage test: the peak value of the test voltage was 40 kV. The voltage is increased gradually to a specified value, and the insulation is not broken down.
The project is higher than the national standard GB/T12706.2 requiring 35KV and 4 h.
8. Before aging and after aging at 100 ℃ by 14d, the volume resistivity of the polypropylene-based semi-conductive conductor shield does not exceed 1000 ohm.m; the volume resistivity of the non-strippable polypropylene-based semiconductive insulation shield does not exceed 500 omega m.
The project is higher than the national standard GB/T12706.2 and requires 100 ℃ 7 d.
9. Insulating mechanical properties: the tensile strength before aging is not less than 20MPa, and the elongation at break is not less than 350%; after aging for 135 × 10d, the tensile strength is not less than 20MPa, and the elongation at break is not less than 350%.
The project is higher than the national standard GB/T12706.2 requirement of 135 ℃ 7 d.
10. Insulating high-temperature pressure test: k is 0.7, and after the test of multiplying 6 hours at 130 ℃, the indentation depth does not exceed 50 percent.
11. Insulation water absorption test: after a test of 336h at 85 ℃, the water absorption is less than or equal to 0.5mg/cm2。
12. Insulation shrinkage test: the marking distance is 200mm, and the shrinkage rate is less than or equal to 4 percent after a test of 130 ℃ multiplied by 1 h.
Example 2
The present embodiment provides a polypropylene insulated wire core, which has a structure as shown in fig. 1, and includes, in order from inside to outside, a conductor 1, a semiconductive conductor shielding layer 2, an insulating layer 3, and a semiconductive insulation shielding layer 4.
The specific manufacturing method is as follows:
(1) the semi-conductive conductor shielding layer, the insulating layer and the semi-conductive insulating shielding layer are sequentially coated on the conductor through three layers of co-extrusion.
The conductor shielding nominal thickness of the semiconductor conductor shielding layer is 1.0mm, the average thickness is 0.80mm, and the thinnest point thickness is 0.60 mm; the semiconductive conductor shielding layer material is selected from a semiconductive shielding material PBB-B9102 developed by cable group Limited of Shanghai cable of Jiangsu province.
The insulation nominal thickness of the insulation layer is 10.5mm, the average thickness is 10.0mm, and the thickness of the thinnest point is 9.35 mm; the insulating material is polypropylene insulating material PP-JC-0801 developed by Jiangsu Shanghai Cable group Limited.
The semiconductive insulation shield layer insulation shield has a nominal thickness of 0.8mm, an average thickness of 0.60mm and a thinnest point thickness of 0.50 mm. The semiconductive insulation shielding layer material is a semiconductive strippable insulation shielding material PKB-B9302 developed by Jiangsu Shanghai Cable group Limited.
The three-layer co-extrusion process has the following requirements:
from feeding to ejection of compact direction, three-layer is crowded fuselage temperature control altogether as follows:
extruding the polypropylene-based semiconductive conductor shielding material PBB-B9102 in a phi 100 extruder, wherein the temperatures of a first zone to a fourth zone of the extruder are as follows in sequence: 100 ℃/130 ℃/210 ℃;
extruding a polypropylene insulating material PP-JC-0801 in a phi 175 extruder, wherein the temperatures of a first zone to a sixth zone of the extruder are as follows: 80 ℃/140 ℃/200 ℃/225 ℃/225 ℃/225 ℃;
the strippable polypropylene-based semiconductive insulation shielding material PKB-B9302 is extruded in a phi 100 extruder, and the temperatures of a first zone to a fifth zone of the extruder are as follows in sequence: 100 ℃/140 ℃/210 ℃/220 ℃/220 ℃;
wherein: the first zone is a feeding section, the second zone and the third zone are plasticizing sections, and the fourth zone and the following zones are homogenizing sections;
a polypropylene-based semiconductive conductor shielding extruder (phi 100) uses a filter screen with 20 meshes, 80 meshes and 20 meshes;
a polypropylene insulation extruder (phi 175) uses a sieve of 80 meshes plus 200 meshes plus 80 meshes plus 20 meshes;
a strippable polypropylene semi-conductive insulation shielding extruder (phi 100) uses a filter screen with 20 meshes, 80 meshes and 20 meshes;
the temperature of the neck section of a polypropylene-based semiconductive conductor shielding extruder (phi 100) is 200 ℃;
the temperature of the neck section of a polypropylene insulating extruder (phi 175) is 225 ℃;
the temperature of the neck section of a strippable polypropylene semi-conductive insulation shielding extruder (phi 100) is 220 ℃;
the polypropylene-based semiconductive conductor shielding extruder (phi 100), the polypropylene insulation extruder (phi 175) and the strippable polypropylene semiconductive insulation shielding extruder (phi 100) use a three-layer co-extrusion machine head, the machine head is heated by an oil thermal mold temperature instrument, and the temperature is set to be 245 ℃ or 245 ℃.
All temperature settings described above allow a deviation of ± 5 ℃.
(2) And cooling by adopting cold water after extrusion, wherein the temperature of the cooling water is 10 ℃, and thus the polypropylene insulated wire core is obtained.
The obtained polypropylene insulated wire core is detected, and in the embodiment, the performance parameters of the cable core are as follows:
1. routine alternating voltage test: and applying power frequency alternating current voltage of 65kV for 30min between the conductor and the metal shield according to the GB/T12706.3 standard, wherein the cable is not broken down.
2. Partial discharge test: applying 1.73U between conductor and metal shield0There was no measurable discharge exceeding the stated sensitivity (5pC or better).
3. Bending test and subsequent partial discharge test:
the diameter of the bending test cylinder satisfies:
20(D + D) +/-5% single-core non-armor
Bending for three times; subsequent partial discharge experiments, no measurable discharge exceeding the stated sensitivity (5pC or better). (D-diameter of curved core, D-diameter of cable)
4. Measurement of tan δ at room temperature: AC voltage U0The tan delta measured value satisfies not more than 20X 10-4。
5. Heating cycle test: the heating cycle is continued for at least 8h, and during each heating process, the conductor temperature is maintained at 5-10 deg.C for at least 2h, and then naturally cooled in air for at least 3h to make the conductor temperature not exceed 10 deg.C. The cycle was repeated 20 times. After cycle 20, a partial discharge test was performed without any measurable discharge exceeding the stated sensitivity (5pC or better).
When the sample is subjected to thermal cycling, the tan delta of the sample is measured at least once when the temperature of the sample exceeds the maximum operating temperature (5-10) DEG C of a conductor according to the regulation of GB/T3048.11-2007. At an alternating voltage U0The tan delta measurement satisfies not more than 40X 10-4。
After the 20 th cycle, the measurement of tan. delta. at room temperature was carried out in accordance with the regulation of GB/T3048.11-2007. AC voltage U0The tan delta measured value satisfies not more than 20X 10-4。
6. Impulse voltage test and subsequent power frequency voltage test: the temperature of the conductor exceeds the maximum operation temperature (5-10) DEG C of the conductor, the impulse voltage meeting the GB/T12706.3 requirement is applied, the positive impulse voltage is applied for 10 times, and the cable is not broken down; after the impulse voltage test, a routine ac voltage test was performed, with no breakdown of the insulation.
7. 4h voltage test: the test voltage peak was 104 kV. The voltage is gradually increased to a specified value, and the insulation is satisfied without breakdown.
8. Before aging and after aging at 100 ℃ by 14d, the volume resistivity of the polypropylene-based semiconductive conductor shield does not exceed 1000 omega m; the volume resistivity of the strippable polypropylene-based semiconductive insulation shield does not exceed 500 omega m.
9. Insulating mechanical properties: the tensile strength before aging is not less than 20MPa, and the elongation at break is not less than 350%; after aging for 135 × 10d, the tensile strength is not less than 20MPa, and the elongation at break is not less than 350%.
The project is higher than the national standard GB/T12706.2 requirement of 135 ℃ 7 d.
10. Insulating high-temperature pressure test: k is 0.7, and after the test of multiplying 6 hours at 130 ℃, the indentation depth does not exceed 50 percent.
11. Insulation water absorption test: after a test of 85 ℃ for 336h, the water absorption is less than or equal to 0.5mg/cm2。
12. Insulation shrinkage test: the marking distance is 200mm, and the shrinkage rate is less than or equal to 4 percent after a test of 130 ℃ multiplied by 1 h.
13. Insulation shield strippability test: the test was carried out 3 times each on the samples before and after aging, the peel angle was 180 DEG, the peel speed (250 + -50) mm/min, and the peel force of the insulation shield was not less than 4N and not more than 45N. The insulating surface meets the requirements of no damage and residual semiconductive shielding traces.
Comparative example 1
The comparative example provides a polypropylene insulated wire core, and the specific manufacturing method comprises the following steps:
(1) the semi-conductive conductor shielding layer, the insulating layer and the semi-conductive insulating shielding layer are sequentially coated on the conductor through three layers of co-extrusion.
Wherein: the semiconductive conductor shielding layer is extruded polypropylene-based cross-linked semiconductive conductor shielding material, the nominal thickness of the conductor shielding is 1.0mm, the average thickness is 0.80mm, and the thinnest point thickness is 0.60 mm.
The insulating layer is formed by extruding polypropylene insulating material, the nominal thickness of the insulating layer is 10.5mm, the average thickness is 10.5mm, and the thickness of the thinnest point is 9.35 mm.
The semiconductive insulation shielding layer is formed by extruded polypropylene-based cross-linked semiconductive insulation shielding materials, the nominal thickness of the insulation shielding is 0.8mm, the average thickness is 0.60mm, and the thinnest point thickness is 0.50 mm.
The polypropylene-based crosslinked semiconductive conductor shielding material and the polypropylene-based crosslinked semiconductive insulation shielding material are prepared from the following raw materials in parts by mass:
30-70 parts by mass of isotactic polypropylene (ipp):
30-70 parts by mass of an ethylene-propylene copolymer (30-50% by mass of ethylene):
2-5 parts of Mgo nano particles are modified to be used as a base material:
1-2 parts of low-silica-alumina-ratio zeolite for light industry:
10-15 parts by mass of acetylene black:
0.1-1 part by mass of an antioxidant;
1-5 parts by mass of a peroxide crosslinking agent.
The polypropylene insulating material adopts polypropylene insulating material PP-JC-0801 developed by cable group Limited in Shanghai, Jiangsu province.
The three-layer co-extrusion process requirements are as follows:
from the feeding to the ejection of compact direction, three-layer crowded fuselage temperature control altogether is as follows:
extruding the polypropylene-based cross-linked semiconductive conductor shielding material in a phi 100 extruder, wherein the temperatures of a first area to a fourth area of the extruder are as follows in sequence: 100 ℃/130 ℃/210 ℃/210 ℃;
extruding the polypropylene insulating material in a phi 175 extruder, wherein the temperatures of a first zone to a sixth zone of the extruder are as follows: 80 ℃/140 ℃/200 ℃/225 ℃/225 ℃/225 ℃;
extruding the polypropylene-based cross-linked semiconductive insulation shielding material in a phi 100 extruder, wherein the temperatures of a first area to a fifth area of the extruder are as follows: 100 ℃/140 ℃/210 ℃/220 ℃/220 ℃;
wherein: the first zone is a feeding section, the second zone and the third zone are plasticizing sections, and the fourth zone and the following zones are homogenizing sections;
a polypropylene-based cross-linked semiconductive conductor shielding material extruder (phi 100) uses a filter screen with 20 meshes, 80 meshes and 20 meshes;
a polypropylene insulating extruder (phi 175) uses a filter screen with 80 meshes, 200 meshes, 80 meshes and 20 meshes;
a polypropylene-based cross-linking semiconductive insulation shielding material extruder (phi 100) uses a filter screen with 20 meshes, 80 meshes and 20 meshes;
the temperature of the neck section of a polypropylene-based cross-linked semiconductive conductor shielding material extruder (phi 100) is 200 ℃;
the temperature of the neck section of a polypropylene insulating extruder (phi 175) is 225 ℃;
the neck section temperature of a polypropylene-based cross-linking semiconductive insulation shielding material extruder (phi 100) is 220 ℃;
the polypropylene-based cross-linked semiconductive conductor shielding material extruder (phi 100), the polypropylene insulation extruder (phi 175) and the polypropylene-based cross-linked semiconductive insulation shielding material extruder (phi 100) use a three-layer co-extrusion machine head, the machine head is heated by an oil thermal mold temperature instrument, and the temperature is set to be 245 ℃/245 ℃.
All temperature settings described above were allowed to be + -5 deg.C.
After extrusion, the mixture is cooled by cold water, and the temperature of the cold water is 10 ℃.
The insulated wire core produced by adopting the process fails to be produced and cannot be extruded, and the reason is as follows:
1. at the extrusion temperature, the polypropylene semi-conductive shielding material in the comparative example is pre-crosslinked under the action of the peroxide crosslinking agent, has no fluidity, and cannot be extruded together with the thermoplastic polypropylene insulating material to form an insulating wire core of the cable.
2. During extrusion, such high temperatures cause the peroxide crosslinking agent to penetrate into the insulation layer, thereby causing a crosslinking reaction locally (in contact with the shield layer) of the insulation layer, thereby losing its thermoplastic benefits.
The conclusion is that: the thermoplastic polypropylene insulating material and the cross-linked shielding material cannot be co-extruded in three layers, and if single layers are extruded successively, the defects that air gaps and the like cannot be tightly bonded exist inevitably between the shielding layer and the insulating layer, so that the cable generates partial discharge in a test and cannot be used for an insulating wire core of a medium-voltage cable.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. This need not be, nor should it be exhaustive of all embodiments. And obvious variations or modifications derived therefrom are intended to be within the scope of the invention.
Claims (9)
1. A polypropylene insulated wire core comprises a conductor, a semi-conductive conductor shielding layer, an insulating layer and a semi-conductive insulated shielding layer from inside to outside, and is characterized in that the semi-conductive conductor shielding layer is composed of polypropylene semi-conductive conductor shielding materials, the insulating layer is composed of polypropylene insulating materials, and the semi-conductive insulated shielding layer is composed of polypropylene semi-conductive insulated shielding materials.
2. The polypropylene insulated wire core of claim 1,
the conductor is a second type of twisted compacted copper or aluminum conductor;
the polypropylene-based semiconductive conductor shielding material comprises raw materials of polypropylene, a thermoplastic elastomer, carbon black and a processing aid;
the raw materials of the polypropylene insulating material comprise polypropylene, a thermoplastic elastomer and a processing aid;
the polypropylene-based semiconductive insulation shielding material comprises polypropylene, a thermoplastic elastomer, carbon black and a processing aid.
3. The polypropylene insulated wire core according to claim 2,
the polypropylene-based semi-conductive insulation shielding material is a strippable polypropylene semi-conductive insulation shielding material or a non-strippable polypropylene semi-conductive insulation shielding material.
4. The polypropylene insulated wire core of claim 3,
the polypropylene-based semiconductive conductor shielding material and the non-strippable polypropylene semiconductive insulation shielding material are the same in raw material, and comprise the following raw materials in parts by weight:
the polypropylene insulating material comprises the following raw materials in parts by weight:
the strippable polypropylene-based semiconductive insulation shielding material comprises the following raw materials in parts by weight:
5. polypropylene insulated wire core according to any of the claims 1 to 4,
the diameter of the conductor is from 6.0mm to 34.0 mm;
the thickness of the shielding layer of the semiconductor conductor is 0.50mm-1.40 mm;
the nominal thickness of the insulating layer is 2.50mm-10.5 mm;
the thickness of the semiconductive insulating shielding layer is 0.50mm-1.20 mm.
6. The process for the preparation of a polypropylene insulated wire core as claimed in any one of claims 1 to 5, comprising the steps of:
s1: selecting a polypropylene-based semiconductive conductor shielding material, a polypropylene insulating material and a polypropylene-based semiconductive insulating shielding material;
s2: covering the conductor with polypropylene-based semiconductive conductor shielding material to form a semiconductive conductor shielding layer;
s3: coating polypropylene insulating material on the shielding layer of the semi-conductive conductor
S4: covering the polypropylene-based semiconductive insulation shielding material on the insulation layer to form a semiconductive insulation shielding layer;
s5: and cooling to obtain the polypropylene insulated wire core.
7. The method of claim 6, wherein the coating in steps S2, S3 and S4 is a three-layer co-extrusion, and the polypropylene-based semiconductive conductor shielding material, the polypropylene-based insulating material and the polypropylene-based semiconductive insulating material are sequentially coated on the conductor to form the semiconductive conductor shielding layer, the insulating layer and the semiconductive insulating shielding layer.
8. The production method according to claim 7, wherein in the triple co-extrusion,
setting the temperature of a polypropylene semiconductive conductor shielding material extruder to be 80-210 ℃ from the feeding direction to the discharging direction;
setting the temperature of the polypropylene insulating material extruder to be 80-210 ℃ from the feeding direction to the discharging direction;
from the feeding direction to the discharging direction, the temperature of the polypropylene semi-conductive insulation shielding extruder is set as follows: 80-220 ℃;
the temperature of the machine neck section of the polypropylene semi-conductive conductor shielding material extruder is 190-210 ℃;
the temperature of the machine neck section of the polypropylene insulating material extruder is 195-240 ℃;
the temperature of the neck section of the polypropylene semi-conductive insulating shielding material extruder is 190-220 ℃;
the polypropylene semi-conductive conductor shielding material extruder, the polypropylene insulating material extruder and the polypropylene semi-conductive insulating shielding material extruder use a three-layer co-extruder head, and the temperature of the extruder head is 215-255 ℃.
9. The method according to any one of claims 6 to 8, wherein the cooling in step S5 is cooling using a water bath, and the water temperature is 10 to 40 ℃.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116864235A (en) * | 2023-08-31 | 2023-10-10 | 中国电力科学研究院有限公司 | Method for manufacturing polypropylene insulated power cable and cable manufactured by same |
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| CN109378136A (en) * | 2018-11-21 | 2019-02-22 | 江苏上上电缆集团有限公司 | A kind of manufacturing method and cable of environmental protection medium-pressure power cable |
| US20220112367A1 (en) * | 2018-06-13 | 2022-04-14 | Nexans | Polymer composition comprising a dielectric liquid of improved polarity |
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| US20220112367A1 (en) * | 2018-06-13 | 2022-04-14 | Nexans | Polymer composition comprising a dielectric liquid of improved polarity |
| CN109111619A (en) * | 2018-07-06 | 2019-01-01 | 江苏上上电缆集团有限公司 | A kind of novel environment-friendly semi-conductive shielding material and preparation method thereof |
| CN109378136A (en) * | 2018-11-21 | 2019-02-22 | 江苏上上电缆集团有限公司 | A kind of manufacturing method and cable of environmental protection medium-pressure power cable |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116864235A (en) * | 2023-08-31 | 2023-10-10 | 中国电力科学研究院有限公司 | Method for manufacturing polypropylene insulated power cable and cable manufactured by same |
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