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CN-122011620-A - Biaxially oriented cable protection tube

CN122011620ACN 122011620 ACN122011620 ACN 122011620ACN-122011620-A

Abstract

The application discloses a biaxially oriented cable protective tube which comprises the following raw materials, by mass, 100 parts of PVC resin, 5-15 parts of a plasticizer, 3-8 parts of maleic anhydride grafted EVA, 2-5 parts of a heat stabilizer, 0.5-1.5 parts of a lubricant and 5-10 parts of a filler, wherein the plasticizer at least comprises pyridyl modified adipic acid polyester. The application can effectively solve the problems of tensile tearing and collapse caused by insufficient melt strength of plasticized and toughened modified PVC in the biaxial orientation process.

Inventors

  • LI MINFU
  • HUANG LIANJIN
  • LI HANGQI
  • SHI YANG

Assignees

  • 浙江杭欧新材料股份有限公司

Dates

Publication Date
20260512
Application Date
20260310

Claims (10)

  1. 1. The biaxially oriented cable protective tube is characterized by comprising, by mass, 100 parts of PVC resin, 5-15 parts of a plasticizer, 3-8 parts of maleic anhydride grafted EVA, 2-5 parts of a heat stabilizer, 0.5-1.5 parts of a lubricant and 5-10 parts of a filler, wherein the plasticizer at least comprises pyridyl modified adipic acid polyester, the preparation method of the biaxially oriented cable protective tube comprises the steps of uniformly mixing the raw materials of the cable protective tube, carrying out melt extrusion to obtain a tube blank, spraying an aqueous solution containing metal ions on the surface of the tube blank, heating the cooled tube blank to an orientation temperature, carrying out synchronous biaxial stretching, and carrying out cooling and shaping.
  2. 2. The biaxially oriented cable protective tube according to claim 1, wherein the pyridyl modified adipic acid polyester is prepared by esterification polycondensation of adipic acid, dipicolinic acid and propylene glycol in a molar ratio of 1:0.05-0.1:1.1-1.2.
  3. 3. The biaxially oriented cable protective tube according to claim 1, wherein the pyridyl-modified adipic acid polyester has a number average molecular weight of 2000 to 4000.
  4. 4. The biaxially oriented cable protective tube according to claim 2, wherein the dipicolinic acid is 2, 5-dipicolinic acid or 2, 6-dipicolinic acid.
  5. 5. The biaxially oriented cable protective tube according to claim 1, wherein the metal ion is selected from one or more of Ni 2+ 、Zn 2+ 、Cu 2+ , and the concentration of the metal ion in the cooling water is 0.01 to 0.1mol/L.
  6. 6. The biaxially oriented cable protective tube according to claim 1, wherein the filler is a modified filler having surface grafted siloxane groups.
  7. 7. The biaxially oriented cable protective tube according to claim 6, wherein the modified filler is produced by a process comprising: carrying out surface modification on the filler by adopting a vinyl silane coupling agent to obtain a vinyl filler; And (3) performing hydrosilylation on the vinyl filler and hydrogen-containing silane to obtain the siloxane modified filler.
  8. 8. The biaxially oriented cable protective tube according to claim 7, wherein the mass ratio of the filler, the vinyl silane coupling agent, and the hydrogen-containing silane is 100:3 to 6:2 to 5.
  9. 9. The biaxially oriented cable protective tube according to claim 7, wherein the hydrogen-containing silane is one or more selected from trimethoxysilane, triethoxysilane, methyldimethoxysilane, ethyldimethoxysilane.
  10. 10. The biaxially oriented cable protective tube according to any one of claims 1 to 9, wherein the filler is an inorganic microsphere having a sphericity of not less than 0.8, and is at least one selected from the group consisting of spherical silica, spherical calcium carbonate and spherical talc.

Description

Biaxially oriented cable protection tube Technical Field The application relates to the field of PVC materials, in particular to a biaxially oriented cable protection tube. Background Biaxially oriented polyvinyl chloride (PVC-O) cable protective tubing is widely used in the field of underground electrical communication engineering due to its excellent loop stiffness, impact resistance and dimensional stability. The molecular chains are orderly arranged along two directions by applying axial traction and radial internal pressure to the PVC pipe blank under the high-elastic state, so that the mechanical property is obviously improved. However, to meet the demands of cold areas, the prior art has often incorporated small molecular plasticizers (such as DOP) and rubber-based impact modifiers (such as CPE, MBS, EVA) into PVC systems to improve low temperature brittleness. Although the flexibility of the additive can be improved, the melt strength and the high-elastic modulus of the material in an orientation temperature window are seriously weakened, so that the pipe cannot bear bidirectional tension in the synchronous biaxial stretching process to generate local necking, tearing and even collapse, and stable continuous production is difficult to realize. In addition, the micromolecular plasticizer is easy to migrate and separate out, and the pipe is hardened and embrittled after long-term use, so that the application of the micromolecular plasticizer in the field of high-end cable protection is further limited. Disclosure of Invention The application aims to solve the problems of tensile tearing and collapse caused by insufficient melt strength of plasticized and toughened modified PVC in the biaxial orientation process. The application provides a biaxially oriented cable protective tube which comprises the following raw materials, by mass, 100 parts of PVC resin, 5-15 parts of a plasticizer, 3-8 parts of maleic anhydride grafted EVA, 2-5 parts of a heat stabilizer, 0.5-1.5 parts of a lubricant and 5-10 parts of a filler, wherein the plasticizer at least comprises pyridyl modified adipic acid polyester. In any of the above technical schemes, the pyridyl modified adipic acid polyester is prepared by esterification polycondensation of adipic acid, dipicolinic acid and propylene glycol with a molar ratio of 1:0.05-0.1:1.1-1.2. In any of the above technical solutions, the number average molecular weight of the pyridyl modified adipic acid polyester is 2000-4000. In any of the above embodiments, the dipicolinic acid is 2, 5-dipicolinic acid or 2, 6-dipicolinic acid. In any of the above technical solutions, the metal ion is selected from one or more of Ni 2+、Zn2+、Cu2+. In any of the above technical schemes, the concentration of metal ions in the aqueous solution is 0.01-0.1 mol/L, the temperature of the aqueous solution is 55-70 ℃, and the spraying amount is 80-120 mL/m 2 pipe blank surface area. According to the application, by introducing pyridyl modified adipic acid polyester and maleic anhydride modified EVA and improving a cooperative cooling spraying process, a pipe reinforcing mechanism of 'self-reinforcing during processing without interference and orientation' is realized. Specifically, in the cooling stage of the extruded pipe blank, metal ions (such as Zn 2+) in spray cooling water are quickly infiltrated into the surface layer by utilizing the pipe body waste heat, and a multi-tooth coordination bond is formed between the metal ions, carboxyl provided by maleic anhydride grafting EVA in the system and pyridine nitrogen atoms and terminal carboxyl in pyridyl modified adipic acid polyester. Because the pyridine ring has strong coordination capability, the pyridine ring can be used for constructing a stable five-membered or six-membered chelate ring with transition metal ions, so that a three-dimensional coordination cross-linked network is constructed in situ in the forward pipe. The network keeps complete at orientation temperature, obviously improves the elastic modulus and tensile strength, effectively supports the synchronous biaxial stretching process, avoids tearing and collapsing, simultaneously has extremely low mobility of a high molecular weight polyester main chain, further anchors a plasticizing chain segment through coordination, fundamentally inhibits precipitation, and ensures long-term cold resistance. The maleic anhydride modified EVA has good toughening effect and good compatibility with the PVC resin matrix, so that the coordination network can be effectively dispersed in the resin matrix, and good reinforcing effect is achieved. In any of the above embodiments, after the aqueous solution containing metal ions is sprayed, the tube blank is put into a cooling water tank, and the tube blank is cooled to 40 ℃ or lower. In any of the above technical solutions, the orientation temperature is 100 to 130 ℃. In any of the above technical schemes, the VA content in the maleic anhydride grafted EV