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CN-121641558-B - Cold-resistant power cable based on modified elastomer sheath and preparation method thereof

CN121641558BCN 121641558 BCN121641558 BCN 121641558BCN-121641558-B

Abstract

The invention relates to the technical field of power cables, and discloses a cold-resistant power cable based on a modified elastomer sheath and a preparation method thereof, aiming at solving the problem of interface failure caused by asynchronous dielectric properties of an insulating layer and a sheath layer along with temperature change when the existing cold-resistant cable runs in a low-temperature environment for a long time; the outer sheath layer is made of a modified elastomer material composed of chlorinated polyethylene, specific polyester and low-temperature plasticizer, and the temperature response behavior of the dielectric constant of the cable is actively regulated and controlled by regulating the flexibility of a molecular chain, so that the cable is in dielectric matching with the insulating layer at low temperature, the electric field distortion at the interface between insulation and the sheath at low temperature is inhibited, and the electrical stability and long-term operation reliability of the interface of the cable in an extremely low-temperature environment are improved.

Inventors

  • JIAO YUNFU
  • LIU YUCHENG
  • LIU JIAYIN
  • ZHAO LINLIN
  • WANG TIANWEI

Assignees

  • 锐洋集团东北电缆有限公司

Dates

Publication Date
20260508
Application Date
20260203

Claims (10)

  1. 1. The cold-resistant power cable based on the modified elastomer sheath is characterized by comprising a conductor, an insulating layer, a wrapping tape layer, a filling layer, an armor layer and an outer sheath layer which are sequentially arranged from inside to outside, wherein the insulating layer is formed by an insulating composite material, the insulating composite material comprises a rubber matrix, a thermoplastic polyurethane elastomer and cyanoethylated pentaerythritol, the cyanoethylated pentaerythritol is chemically bonded with a crosslinked network of the insulating composite material through hydroxyl groups in molecules of the cyanoethylated pentaerythritol, the outer sheath layer is formed by a sheath material, the sheath material comprises chlorinated polyethylene, poly (1, 2-propylene glycol) adipate and dibutyl diglycidylester, and the poly (1, 2-propylene glycol) adipate and dibutyl diglycidylester jointly form a modified system to regulate the molecular chain flexibility of the chlorinated polyethylene.
  2. 2. The cold-resistant power cable based on modified elastomer jacket according to claim 1, wherein the insulation composite comprises, by mass, 50-65 parts of a rubber matrix, 15-25 parts of a thermoplastic polyurethane elastomer, 3.0-5.0 parts of cyanoethylated pentaerythritol, 4.0-7.0 parts of modified nano silica, 12-20 parts of dioctyl sebacate, 1.5-2.5 parts of dicumyl peroxide, 1.0-1.8 parts of triallyl isocyanurate and 0.5-1.0 parts of antioxidant 1010.
  3. 3. The cold-resistant power cable based on modified elastomer sheath according to claim 2, wherein the sheath material comprises, by mass, 55-70 parts of chlorinated polyethylene, 8.0-15.0 parts of poly (1, 2-propylene glycol) adipate, 15-25 parts of dibutyl diglycol adipate, 20-30 parts of carbon black N550, 2-4 parts of epoxidized soybean oil and 3-5 parts of composite lead salt stabilizer.
  4. 4. The cold-resistant power cable based on modified elastomer sheath according to claim 2, wherein the rubber matrix is hydrogenated nitrile rubber, the acrylonitrile content of the hydrogenated nitrile rubber is 34% -36%, and the hydrogenation degree is more than or equal to 98%.
  5. 5. The cold-resistant power cable based on modified elastomer jacket according to claim 2, wherein the average substitution degree of cyanoethyl of cyanoethylated pentaerythritol is more than or equal to 3.5, and the hydroxyl value is less than or equal to 50mgKOH/g.
  6. 6. The cold-resistant power cable based on modified elastomer jacket according to claim 2, wherein the modified nano silica is nano silica with gamma-aminopropyl triethoxysilane treated surface.
  7. 7. A cold-resistant power cable based on a modified elastomeric sheath according to claim 3, wherein said chlorinated polyethylene has a chlorine content of 35% to 38%.
  8. 8. A cold-resistant power cable based on a modified elastomer jacket as claimed in claim 3, wherein the number average molecular weight of the poly (1, 2-propanediol adipate) is 1800-2200 and the acid value is 1.0mgKOH/g or less.
  9. 9. A preparation method of a cold-resistant power cable based on a modified elastomer sheath is used for preparing the cold-resistant power cable based on the modified elastomer sheath according to any one of claims 1-8 and is characterized by comprising the following steps of S1, preparing a conductor core, S2, extruding an insulating rubber material containing a rubber matrix, a thermoplastic polyurethane elastomer and cyanoethylated pentaerythritol into the conductor core to form an insulating layer, S3, carrying out sectional vulcanization on the insulating layer, including microwave preheating and subsequent multi-stage hot air vulcanization, S4, twisting the vulcanized insulating core with a filling material into a cable, and sequentially coating a wrapping layer and an armor layer, S5, extruding a sheath rubber material containing chlorinated polyethylene, poly-1, 2-propanediol adipate and dibutyl diglycol adipate outside the armor layer to form an outer sheath layer, and S6, vulcanizing the outer sheath layer to obtain a finished cable.
  10. 10. The method of claim 9, wherein the multi-stage hot air vulcanization in S3 comprises vulcanizing at 156-160deg.C for 8-10 minutes in the first zone, vulcanizing at 166-170deg.C for 10-12 minutes in the second zone, and vulcanizing at 142-160deg.C for 18-22 minutes in the third zone.

Description

Cold-resistant power cable based on modified elastomer sheath and preparation method thereof Technical Field The invention relates to the technical field of power cables, in particular to a cold-resistant power cable based on a modified elastomer sheath and a preparation method thereof. Background In a power transmission network in a high latitude and severe cold region, a cold-resistant power cable is a key infrastructure for guaranteeing the reliability of a power supply system, and is used as a protection and mechanical support structure of the outermost layer of the cable, and a sheath layer needs to keep excellent flexibility, mechanical strength and environmental tolerance for a long time in an extremely low-temperature environment. The related prior art has many explored this, for example, chinese patent application CN118725433a discloses a cold-resistant sheath material for cables, which is prepared by grafting and modifying a side chain of neoprene and matching with a specific modified plasticizing filler to balance cold resistance and mechanical properties of the material, and another chinese patent application CN119331321a discloses an antifreezing power cable, wherein an outer sheath adopts a blending system of benzene rubber and silicone rubber, and surface-modified i Li Danfen is added, so as to improve low temperature resistance and physical strength of the sheath. The dielectric constant (epsilon) of the polymer dielectric is not a fixed value, and researchers such as Li Yan and the like indicate that the dielectric constant of the crosslinked polyethylene (XLPE) and the dielectric constant of the oilpaper insulation are reduced regularly along with the reduction of the temperature in the analysis of the influence of the temperature on the dielectric parameters of two cable insulation materials published in the section 55 and the 12 of the journal of polymer science in 2024, and the fact that the orientation polarization capability of polar groups in the material is reduced at low temperature. The experimental data in the same paper show that the curves of the dielectric constants of XLPE and oilpaper insulation along with the change of temperature are not parallel, which means that when the insulation layer and the sheath layer of the cable are subjected to the same low-temperature process, the difference of the dielectric constant change rates of the insulation layer and the sheath layer of the cable causes the ratio to deviate from the normal-temperature design value, so that dielectric mismatch is formed. The dielectric mismatch can directly interfere the electric field distribution at the interface of the cable insulation and the sheath, and Yin Yi et al in simulation study of electric field distortion caused by the interface morphology of the main insulation and the shielding layer of the direct current cable in the 13 th and 11 th periods of the electric engineering journal 2018 prove that when the electric field distribution at the interface of two media is in inverse relation with the dielectric constant, the electric field near the interface can be distorted and distorted, and a region with obviously increased local electric field intensity is formed at one side with relatively higher dielectric constant. The electric field distortion can cause additional max Wei Dian induced stress at the interface, and Li Guochang and other scholars analyze and indicate in the "high voltage direct current cable accessory XLPE/SIR material characteristics and the influence of interface charge accumulation on electric field distribution" in the "technical society of electrical engineering" in the volume 36 and the 14 th stage of 2021, and under the low-temperature environment, the cable high polymer material self embrittles due to the reduction of the activity of a molecular chain segment, and the crack resistance is reduced, and at the moment, the periodic electric induced stress and the brittleness of the material generate a synergistic effect, so that the risk of initiation and expansion of microcracks at the interface is increased. In the prior art and common practice in industry, the inherent electric field characteristics of the power cable during operation are not considered, the dielectric matching requirements of an insulating layer and a sheath layer are ignored, the insulating layer and the sheath layer of the cable are made of polymer materials with different polarities and molecular chain structures, when the ambient temperature suddenly drops, the dielectric constants of the insulating layer and the sheath layer drop, but the rate difference is obvious, the asynchronism of the dielectric constant change causes interface electric field distortion, electric field concentration is formed on one side with relatively high dielectric constant, and further, the uneven electric field can generate periodic max Wei Dian induced stress, and the stress can initiate and accelerate initiation and e