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CN-122011651-A - Grafted modified polypropylene cable material and preparation method thereof

CN122011651ACN 122011651 ACN122011651 ACN 122011651ACN-122011651-A

Abstract

The invention provides a grafted modified polypropylene cable material and a preparation method thereof, belonging to the field of cable materials. The cable material comprises 50-70 parts of styrene grafted polypropylene, 20-40 parts of thermoplastic elastomer, 0.5-2 parts of antioxidant and 5-10 parts of voltage stabilizer, and is prepared by blending the styrene grafted polypropylene, the thermoplastic elastomer, the oxidant and the voltage stabilizer through a torque rheometer and extruding and granulating through double screws. The invention adopts the grafting modified polypropylene, the thermoplastic elastomer, the oxidant and the voltage stabilizer to blend, solves the defects of large brittleness, easy aging and the like of the traditional polypropylene insulating material, and the prepared cable material has excellent insulating property, mechanical toughness and electrical aging resistance, meets the severe requirements of high-voltage and ultra-high-voltage cables on the insulating material, and has wide industrial application prospect.

Inventors

  • ZHANG TAO
  • ZHANG JINYUAN
  • WANG XIAOJUN
  • DU YAOJIE
  • LIU YUANXI
  • ZHI LI

Assignees

  • 三峡大学
  • 湖北宝上电缆有限公司

Dates

Publication Date
20260512
Application Date
20260202

Claims (10)

  1. 1. The grafted modified polypropylene cable material is characterized by comprising, by mass, 50-70 parts of styrene grafted polypropylene, 20-40 parts of a thermoplastic elastomer, 0.5-2 parts of a first antioxidant and 5-10 parts of a voltage stabilizer.
  2. 2. The grafted modified polypropylene cable material of claim 1, wherein the styrene grafted polypropylene is prepared by melt grafting polypropylene, dicumyl peroxide, monomer styrene and a second antioxidant, wherein the mass ratio of the styrene grafted polypropylene to the polypropylene is 100 (0.1-0.5), and the mass ratio of the polypropylene to the dicumyl peroxide is 20 (1.5-2.5).
  3. 3. The grafted modified polypropylene cable material of claim 2, wherein the preparation method of the styrene grafted polypropylene is characterized in that the styrene grafted polypropylene is obtained by mixing and dispersing polypropylene, dicumyl peroxide, monomer styrene and an antioxidant, adding the mixture into a torque rheometer, reacting at a high temperature to obtain a grafted product, and purifying the grafted product.
  4. 4. The grafted modified polypropylene cable material of claim 2, wherein said second antioxidant is a semi-hindered phenolic compound 2908 and said polypropylene is isotactic polypropylene.
  5. 5. The grafted modified polypropylene cable material of claim 2, wherein the grafting rate of the styrene grafted polypropylene is 8% -12%.
  6. 6. The grafted modified polypropylene cable material of claim 1, wherein said thermoplastic elastomer is one or more of EPDM, SEBS, POE, PBE.
  7. 7. The grafted modified polypropylene cable material of claim 1, wherein said first antioxidant is one or more of antioxidants 1010, A0-1010, 1076, 1330, 168.
  8. 8. The grafted modified polypropylene cable material of claim 1, wherein said voltage stabilizer is one or more of aromatic ketone compounds AOHBP, RBBT, RQCT.
  9. 9. The preparation method of the grafted modified polypropylene cable material according to any one of claims 1 to 8, which is characterized by comprising the following steps: (1) Sequentially adding styrene grafted polypropylene, a thermoplastic elastomer and a first antioxidant into a rheometer according to mass ratio, uniformly mixing, adding a voltage stabilizer, and continuously blending to obtain a mixed material; (2) Adding the mixed material obtained in the step (1) into a co-rotating double-screw extruder, controlling the temperature of a machine barrel, the rotating speed of a host machine and the rotating speed of a feeding screw, extruding and granulating to obtain the grafted modified polypropylene cable material.
  10. 10. The method of claim 9, wherein in the step (2), the barrel temperature is 180-220 ℃, the main machine rotation speed is 80-120rpm, and the feeding screw rotation speed is 20-40rpm.

Description

Grafted modified polypropylene cable material and preparation method thereof Technical Field The invention relates to the technical field of cable materials, in particular to a grafted modified polypropylene cable material and a preparation method thereof. Background Compared with the traditional cross-linked polyethylene (XLPE) material, the polypropylene (PP) cable insulating material has excellent performance in heat resistance, insulativity and mechanical strength, has relatively simple production process, does not need cross-linking, can realize recycling, and is widely recognized by industry as a potential material for replacing XLPE cable insulation. However, the pure PP has obvious short performance board, namely high crystallinity, high rigidity and poor toughness, is difficult to meet the bending requirement of the high-voltage direct-current cable on the mechanical property of the insulating material, and on the other hand, space charge accumulation is easy to occur in a high-voltage direct-current environment, so that local electric field distortion is caused, and insulation aging is accelerated. In order to improve the mechanical toughness and electrical performance of polypropylene, the prior art generally carries out copolymerization reaction on PP and other olefin monomers to prepare copolymerized polypropylene (IPC), however, in the actual production of the IPC, the specific blending amount of ethylene is used as a key comonomer, the regulating and controlling effects of the specific blending amount on the final performance of the material are obviously different, and the optimal interval of the blending amount of ethylene is not agreed in the industry at present. A part of researches show that the nano particle modified PP or the organic nucleating agent induces the beta crystal form to form, so that the electrical property and mechanical toughness of the PP can be effectively improved, but nano particles are easy to agglomerate, interface defects are caused, batch stability is affected, and the nucleating agent is easy to migrate and separate out from a matrix in a long-term high-temperature service process, so that a crystal structure is relaxed, and long-term reliability is to be verified. In recent years, grafting polar functional groups onto nonpolar polymers has been an effective way to modulate the charge transport properties of the polymers and to improve the electrical properties of the polymers. Styrene is used as an unsaturated vinyl compound, and its characteristic benzene ring structure affects the injection and migration processes of space charges. Patent CN121086408a discloses a self-reinforced polypropylene cable insulation material, which is formed by grafting a polar vinyl monomer (such as styrene) onto a PP main chain to form a polypropylene graft copolymer to induce beta crystal form generation, and utilizes a polar group to construct a deep level charge trap, so that space charge accumulation is effectively inhibited, and breakdown strength and heat distortion temperature are improved. However, the elongation at break of this material is only about 224%, limiting its application in cable scenarios requiring repeated bending. Patent CN119119636a discloses a polypropylene cable insulation material with long-term electrical aging resistance and high dielectric property, which adopts a free radical regulation type voltage stabilizer containing xanthate groups, combines functional fillers and polymer elastomers (such as SEBS and POE), enables the voltage stabilizer and the fillers to be stably dispersed in a PP phase through a two-step extrusion process, remarkably prolongs the breakdown life of the material under high pressure, solves the problems of electrical dendrite and free radical aging, improves the mechanical property (tensile strength of 21.4-22.8MPa and elongation at break of 400.8-429.3%), but leads to weakening of the dielectric property due to insufficient interfacial compatibility, and has limited space charge inhibition capability without introducing deep traps on a PP main chain through molecular design. In addition, the PP-g-St is melt blended with the thermoplastic elastomer to improve toughness while retaining excellent electrical properties of the PP-g-St. However, because the poor compatibility between the thermoplastic elastomer and the PP-g-St matrix results in a local aggregation area of the elastomer, when the composite material is applied to a high-voltage environment, the local electric field of the area exceeds the breakdown field strength of the composite material, and the insulation failure risk is further induced. In summary, the existing polypropylene composite material is difficult to realize the cooperative optimization of mechanical, electrical and ageing resistance. Therefore, development of a novel polypropylene cable insulation material is needed to synchronously realize high breakdown strength, high elongation at break, low electric f