Patent Application
20240062935
The present disclosure belongs to the field of polymer materials technology and science, and particularly relates to a stress-resistant, creep-resistant, high-temperature resistant and high-insulation sheath material for a 620 km/h maglev train, and a manufacturing method and use thereof.
The successful operation of a 620 km/h maglev train has greatly filled a speed gap between China's high-speed rail and air transportation, but it also puts forward higher requirements for structural size, electrical performance, mechanical and physical performance, and safety performance of cables. It is necessary to achieve long-term stable operation of materials under high temperature, high stress and strong twisting environments.
In Patent Application Publication CN108239322A, high-density polyethylene is used as a carrier to be mixed with carbon black and extruded together with different polyethylene resins so as to prepare high-hardness, wear-resistance high-toughness polyethylene sheaths, thereby improving the hardness and cracking resistance time of the material. In Patent Application Publication CN104774363A, a blended masterbatches is prepared from vinyl tris(2-methoxyethoxy) silane, tert-butyl benzoyl peroxide and polyethylene, and then blended with a low-density polyethylene matrix, and a silane crosslinked polyethylene cable material is prepared in a closed space with water under the sun so that the cable has a high crosslinking degree. However, the improvement of material performance in the above studies is relatively single, and has not been mentioned in terms of high temperature resistance, stress resistance, etc. The scope of application is relatively low, making it difficult to meet the application requirements in complex environments. At present, the technology related to maglev trains in China is mostly monopolized by foreign countries, so it is of great significance to develop sheath materials with independent intellectual property rights that are resistant to stress, creep, high temperature and high insulation.
The present disclosure provides a stress-resistant, creep-resistant, high-temperature resistant and high-insulation sheath material for a maglev train cable, and a manufacturing method and use thereof. The sheath material comprises the raw materials in parts by weight: 100-150 parts of ultra-high molecular weight polyethylene (UHMWPE); 50-80 parts of functional polyvinylsilicone grease; 50-80 parts of ceramicized silicone rubber; 120-200 parts of phosphorus nitrogen flame retardant; 30-50 parts of reinforcing fillers; 5-10 parts of vulcanizing agent; 1-5 parts of vulcanization accelerator; 1-5 parts of coupling agent; 5-10 parts of compatibilizer; 2-5 parts of lubricant; 1-3 parts of antioxidant; and 1-2 parts of antistatic agent. A multiple chemical crosslinking structure is constructed by blending of a polyvinylsilicone grease with UHMWPE and a ceramicized silicone rubber as a cable material matrix and using electron beam irradiation. In addition, organic/inorganic fillers in the matrix can form physical crosslinking points in the material. A physical-chemical dual crosslinking structure is constructed in the matrix, where the multiple chemical and physical crosslinking structure can limit the motion and relaxation of molecular chains and improve the interaction between the insulation layer and sheath layer and refractory layers such as fillers and mica tapes to avoid the relative shift during the laying and operation and improve the high-temperature resistance, creep resistance and stress relaxation resistance of a UHMWPE cable sheath material.
A specific solution is as follows.
A stress-resistant, creep-resistant, high-temperature resistant and high-insulation sheath material for a maglev train cable, comprising the raw materials in parts by weight:
where z, x, m and n are numbers of repeated units, and are independently integrals between 300 and 500; where the sheath material is prepared by performing melting blend on the UHMWPE, functional polyvinylsilicone grease, ceramicized silicone rubber, phosphorus nitrogen flame retardant, reinforcing filler, coupling agent, compatibilizer, lubricant, antioxidant and antistatic agent in ratios to obtain blended masterbatches and then performing melting blend on the blended masterbatches, vulcanizing agent and vulcanization accelerator to obtain pre-crosslinked masterbatches.
Further, the UHMWPE has a density of 0.92-1.08 g/cm3, a boiling point of 120-140° C., a melt flowing rate of 0.05-0.3 g/10 min under the condition of 190° C./2.16 kg, a molecular weight of 4×106 g/mol-107 g/mol, a shore hardness (D) of 60-65 and a notch impact strength of 50-65 kJ/m2;
A method of manufacturing the sheath material, comprising the following steps:
Further, the method also comprises preparing the functional polyvinylsilicone grease, and specific steps are as follows:
The above copolymer (I) together with hydrothermal reagents, namely 5% NaOH, KOH, NH3·H2O, 2.5% Na2CO3 solution and a 5% ethanol solution is placed in a hydrothermal reactor at the reaction temperature of 400° C. for 4 h to obtain a solid phase product (I) as the functional polyvinylsilicone grease.
where z, x, m and n are numbers of repeated units, which are independently integrals between 300 and 500.
Further, a method of applying the sheath material is as follows:
The present disclosure has the following beneficial effects.
Next, the present disclosure will be described in detail through specific examples, however, the scope of protection of the present disclosure is not limited to these examples.
The raw materials used in the following examples are as follows:
Functional polyvinylsiloxane grease: a four-arm eight-membered cyclic star-shaped polymer containing a large number of unsaturated bonds, which is prepared by the following steps:
The mass fractions of various raw materials in the following examples are seen in Table 1.
Table 1 Raw materials and amounts of stress-resistant, creep-resistant, high-temperature resistant and high-insulation sheath material for maglev train cable (based mass fraction)
Raw materials and formulas in this example are seen in Table 1. The preparation method was carried out according to the following steps:
The above masterbatches together with a vulcanizing agent and a vulcanization accelerator were added into a high-speed mixer for 15 min of blending at 3500 r/min, then the blending was stopped, then the obtained product was placed in a twin-screw extruder for melting blend and extrusion, the processing temperatures were respectively 100° C., 110° C., 120° C., 130° C., 135° C. and 140° C. from the material mouth to the mold mouth, and then the above mixture was cooled and dried to obtained pre-crosslinked masterbatches.
The pre-crosslinked masterbatches were placed in a wire and cable extruder for melting and extrusion on a cable conductor core, the temperature of an inlet was 130° C., the temperature of a first zone was 130-140° C., the temperature of a second zone was 140-150° C., the temperature of a third zone was 150-160° C., the temperature of a fourth zone was 160-170° C., the temperature of a fifth zone was 170-180° C., and the temperature of an outlet was 175° C., the surface of a core of a cable conductor was wrapped with a sheath; and finally the wrapped core was irradiated for 8 min under the conditions that a beam pressure was 1.5-2 MeV, a beam current was 20 mA, and an irradiation dose was 400 kGy to obtain the sheath material.
Raw materials and formulas in this example are seen in Table 1, and the preparation process is the same as that in example 1.
Raw materials and formulas in this example are seen in Table 1, and the preparation process is the same as that in example 1.
Raw materials and formulas in this comparative example are seen in Table 1, and the preparation process is the same as that in example 1
Raw materials and formulas in this comparative example are seen in Table 1, and the preparation process is the same as that in example 1
Raw materials and formulas in this comparative example are seen in Table 1, and the preparation process is the same as that in example 1
Raw materials and formulas in this example are seen in Table 1. The preparation process was carried out according to the following steps:
The pre-blended masterbatches were placed in a wire and cable extruder for melting and extrusion on a cable conductor core, the temperature of an inlet was 130° C., the temperature of a first zone was 130-140° C., the temperature of a second zone was 140-150° C., the temperature of a third zone was 150-160° C., the temperature of a fourth zone was 160-170° C., the temperature of a fifth zone was 170-180° C., and the temperature of an outlet was 175° C., and finally the wrapped core was irradiated for 8 min under the conditions that a beam pressure was 1.5-2 MeV, a beam current was 20 mA, and an irradiation dose was 400 kGy to obtain the material
The main performance indexes of the cable materials obtained in examples 1-3 and comparative examples 1-4 are seen in Table 2.
The test results are as shown in Table 2. The comprehensive performance of example 2 is optimal. Due to a high crosslinking degree in the system and the presence of a rigid structure, the breakage of the molecular chain can be effectively prevented, and the strength and elongation at break of the material are improved. The functional polyvinylsilicone grease can interact strongly with the ceramicized silicone rubber refractory layer to reduce the relative displacement between the refractory layer and the insulation layer, and improve the insulation and fire resistance performance of the material. During the oil resistance test, the movement of molecular chains is limited and difficult to swell, thereby leading to an improvement in oil resistance performance. By comparing example 2 with example 1, it shows that the contents of the functional polyvinylsilicone grease and the ceramicized silicone rubber are proportionally increased, and the crosslinking degree of the materials is increased, thereby resulting in less deformation of the material when being subjected to external forces; the deformation can rapidly restore when the external forces are removed so as to enhance the interaction between the functional polyvinylsilicone grease and the ceramicized silicone rubber refractory layer, leading to an improvement in the overall performance of the material. By comparing example 2 with example 3, it shows that due to the excess of UHMWPE and the ceramicized silicone rubber in example 3, the crosslinking degree of the material is decreased, and an interaction between the functional polyvinylsilicone grease and the refractory layer is weakened, thereby resulting in a decrease in comprehensive performance. By comparing example 2 to comparative example 1, it shows that in comparative example 1, the traditional EVA is used as a matrix, without the addition of the functional polyvinylsilicone grease and the ceramicized silicone rubber, thereby resulting in poor overall performance. By comparing example 2 with comparative examples 2 and 3, it shows that the combination of the functional polyvinylsilicone grease and the ceramicized silicone rubber is not used in formulations of comparative examples, thereby resulting in performance defects existing in the material. In conclusion, it exhibits the superiority of the formula designed in example 2.
Example 1 has the same formula as comparative example 4, but the preparation processes are different. In comparative example 4, due to one-step mixing, the dispersion effect of the filler is poor, and the generation efficiency of free radical during irradiation crosslinking is poor, thereby resulting in a decrease in crosslinking degree, and reflecting the superiority of the preparation process.
Based on the analysis of test data, it can be seen that the performance of the sheath material with stress resistance, creep resistance, high temperature resistance and high insulation for the maglev train cable has been significantly improved due to the following reasons.
In the present disclosure, the functional polyvinylsilicone grease with a specific structure is synthesized and the UHMWPE matrix is introduced by compounding functional polyvinylsilicone grease with the ceramicized silicone rubber. Through irradiation crosslinking, the comprehensive performance of the material is improved, thereby overcoming the problem of stress relaxation and creep that occur in traditional materials under high stress conditions, leading to a rapid decline in the performance of cables under actual operating conditions, and achieving long-term stable operation of cables under high temperature, high stress and strong twisting environments. The materials and related technologies can be applied to cables for 620 km/h maglev trains and related intelligent equipment.
Although the content of the present disclosure has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered a limitation to the present disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present disclosure should be included within the scope of protection of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202210775361.8 | Jul 2022 | CN | national |
This application is a continuation of International Application No. PCT/CN2023/095747, filed on May 23, 2023, which claims priority to Chinese Patent Application No. 202210775361.8, filed on Jul. 1, 2022. All of the aforementioned applications are incorporated herein by reference in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2023/095747 | May 2023 | US |
| Child | 18496779 | US |
