High-speed locomotive cable super-cold-resistant sheath material and preparation method thereof

Abstract

The invention relates to the technical field of cable sheath materials, and provides a high-speed locomotive cable super-cold-resistant sheath material and a preparation method thereof, and the super-cold-resistant sheath material comprises the following raw material components by mass: 60-80 parts of a matrix polymer; 5 to 15 parts of a toughening agent; 3-10 parts of a cold-resistant auxiliary agent; 10 to 20 parts of a flame retardant; 1-5 parts of an antioxidant; 3-10 parts of a nano modified filler; and 1-5 parts of a cross-linking agent. The preparation method comprises the following steps: selecting the raw materials according to the proportion, putting the raw materials into mixing equipment, uniformly mixing to form a primary mixture, and preparing the primary mixture into the composite material through a melt blending process under specific temperature and shearing conditions. The obtained composite material is processed through an extrusion molding process to obtain a sheath material with excellent flexibility, impact resistance and aging resistance, and the problem that an existing material still has embrittlement, cracking or performance reduction in an extremely cold environment is solved.

Description

Technical Field

[0001] The present application relates to the technical field of cable sheath materials, and in particular to an ultra-cold-resistant sheath material for high-speed locomotive cables and a preparation method thereof. Background Art

[0002] As an important part of modern transportation, high-speed locomotives are widely used in passenger and freight transportation due to their high efficiency, safety and comfort. With the advancement of globalization, countries continue to increase their investment in high-speed railway construction, and high-speed locomotives have higher requirements in terms of operating speed, environmental adaptability and reliability. When operating in extremely cold areas, high-speed locomotives have to face harsh low-temperature environments, which puts forward special technical requirements for the material properties of their key components, including the cold resistance of cable sheaths.

[0003] In the existing technology, high-speed locomotive cable sheaths are mainly made of modified polyvinyl chloride (PVC), cross-linked polyethylene (XLPE) or rubber-based materials. These materials optimize the low-temperature flexibility and mechanical properties of the materials by adding modified components such as plasticizers, antioxidants, and cold-resistant agents, thereby meeting the use requirements in conventional low-temperature environments. In addition, some technologies also use multi-layer composite structures, such as designing materials with different characteristics in the inner and outer layers of the cable sheath to take into account insulation, wear resistance and cold resistance. This design enables the cable to maintain good mechanical strength and flexibility in low-temperature environments, ensuring the safe operation of high-speed locomotives.

[0004] Although the above-mentioned technical means can significantly improve the flexibility and durability of high-speed locomotive cable sheaths in low temperature environments, existing materials will still become brittle, crack or have performance degradation problems in extremely cold environments (such as below -40°C), which not only affects the service life of the cable, but may also cause safety hazards in equipment operation. Summary of the invention

[0005] In order to improve the problem that existing materials still suffer from embrittlement, cracking or performance degradation in extremely cold environments, the present application provides an ultra-cold-resistant sheath material for high-speed locomotive cables and a preparation method thereof.

[0006] The invention provides an ultra-cold-resistant sheath material for high-speed locomotive cables, comprising the following raw material components in parts by weight: 60-80 parts of a base polymer; 5-15 parts of a toughening agent; 3-10 parts of a cold-resistant auxiliary agent; 10-20 parts of a flame retardant; 1-5 parts of an antioxidant; 3-10 parts of a nano-modified filler; and 1-5 parts of a cross-linking agent.

[0007] As a preferred embodiment, the matrix polymer is selected from one of polyethylene and ethylene-vinyl acetate copolymer or a combination of at least two thereof.

[0008] As a preferred embodiment, the toughening agent is selected from any one of a maleic anhydride grafted compatibilizer, a styrene-butadiene-styrene block copolymer, and a polypropylene elastomer.

[0009] As a preferred embodiment, the cold-resistant auxiliary agent is selected from silicone oil, low molecular weight polydimethylsiloxane or a combination of at least two thereof; wherein the low molecular weight polydimethylsiloxane refers to polydimethylsiloxane with a molecular weight of less than 10,000.

[0010] As a preferred embodiment, the flame retardant is selected from one or a combination of at least two of aluminum hydroxide and magnesium hydroxide.

[0011] As a preferred embodiment, the antioxidant is selected from one or a combination of at least two of hindered phenol antioxidants and phosphite antioxidants.

[0012] As a preferred embodiment, the nano-modified filler is selected from any one of nano-silicon dioxide and nano-montmorillonite.

[0013] The present application also provides a method for preparing an ultra-cold-resistant sheath material for high-speed locomotive cables, the preparation method comprising the following steps: placing the nano-modified filler in a coupling agent solution, stirring evenly and then performing a high-temperature drying treatment to obtain a pretreated nano-modified filler; wherein the coupling agent is a silane coupling agent; adding the matrix polymer, the toughening agent, the cold-resistant additive, the flame retardant, the antioxidant and the pretreated nano-modified filler to a twin-screw extruder for blending at a preset melting temperature to obtain a primary mixture; adding a cross-linking agent to the primary mixture, and mixing the primary mixture and the cross-linking agent under preset dynamic mixing conditions to obtain a dynamic vulcanized mixture; wherein the cross-linking agent is selected from any one of diisopropyl peroxide and di-tert-butyl peroxyisopropyl benzene; after the dynamic vulcanized mixture is extruded and formed by an extruder, it is placed in a preset low-temperature environment for rapid cooling treatment to obtain an ultra-cold-resistant sheath material.

[0014] As a preferred solution, the preset melting temperature is 170°C to 220°C, and the preset low temperature environment is -60°C to -80°C.

[0015] As a preferred solution, the preset dynamic mixing conditions are a rotation speed of 30-60 r / min and continuous mixing for 5-15 min.

[0016] Compared with the prior art, the present application has the following beneficial effects: By selecting raw materials such as a matrix polymer, a toughening agent, a low-temperature flexibility modifier, an anti-aging agent and a flame retardant according to a specific proportion, and then putting the above raw materials into a mixing device, uniformly mixing to form a preliminary mixture, the preliminary mixture is prepared into a composite material by a melt blending process under specific temperature and shear conditions, the obtained composite material is processed into a sheath material by an extrusion molding process, and the molded sheath material is subjected to a performance test to ensure that it has excellent flexibility, impact resistance and anti-aging performance in a low temperature environment, and improves the problem that the existing materials still tend to become brittle, cracked or have performance degradation in an extremely cold environment. DETAILED DESCRIPTION

[0017] The technical scheme of the present invention is further illustrated by specific examples below. Those skilled in the art should understand that the examples are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0018] Embodiment 1: A super cold-resistant sheath material for high-speed locomotive cables, comprising the following raw material components in parts by weight: Polyethylene (PE): 55 parts; Ethylene-vinyl acetate copolymer (EVA, vinyl acetate unit content is 40wt%): 20 parts; Maleic anhydride grafted compatibilizer (SEBS-g-MAH): 5 parts; Silicone oil: 5 parts; Aluminum hydroxide: 10 parts; Hindered phenol antioxidant: 2 parts; Nano silicon dioxide: 3 parts; Dicumyl peroxide (DCP): 2 parts.

[0019] The preparation method is as follows: The nano-silica was placed in an ethanol solution of a silane coupling agent KH-550, stirred evenly, and dried at 120° C. for 3 hours to obtain a pretreated nano-modified filler; Raw material mixing: PE, EVA, SEBS-g-MAH, silicone oil, aluminum hydroxide, hindered phenol antioxidant and pretreated nano-modified filler are added into a twin-screw extruder according to the formula ratio, and melt-blended at a temperature of 190° C. to obtain a primary mixture; Dynamic vulcanization: DCP was added to the primary mixture, and the mixture was dynamically mixed in a twin-screw extruder at a speed of 50 r / min for 8 minutes to obtain a dynamically vulcanized mixture; Molding and cooling: After the dynamically vulcanized mixture is extruded through an extruder, it is placed in a low temperature environment of -70°C for rapid cooling to obtain an ultra-cold-resistant sheath material.

[0020] Test results: The sheath material maintains excellent flexibility at -60°C, with a tensile strength of 18 MPa, an elongation at break of 300%, and a flame retardant performance of UL94 V-0.

[0021] Embodiment 2: A super cold-resistant sheath material for high-speed locomotive cables, comprising the following raw material components in parts by weight: Polyethylene (PE): 60 parts; Ethylene-vinyl acetate copolymer (EVA, vinyl acetate unit content is 50wt%): 15 parts; Styrene-butadiene-styrene block copolymer (SBS): 6 parts; Low molecular weight polydimethylsiloxane (referring to polydimethylsiloxane with a molecular weight of less than 10,000): 6 parts; Magnesium hydroxide: 12 parts; Phosphite antioxidant: 3 parts; Nano-montmorillonite: 4 parts; Di-tert-butylperoxyisopropylbenzene (BIPB): 2 parts.

[0022] The preparation method is as follows: Pretreatment of nano-modified filler: placing nano-montmorillonite in a methanol solution of silane coupling agent KH-570, stirring evenly, and drying at 110° C. for 4 hours to obtain a pretreated nano-modified filler; Raw material mixing: PE, EVA, SBS, low molecular weight polydimethylsiloxane, magnesium hydroxide, phosphite antioxidant and pretreated nano-modified filler are added into a twin-screw extruder according to the formula ratio, and melt-blended at a temperature of 200° C. to obtain a primary mixture; Dynamic vulcanization: BIPB was added to the primary mixture, and the mixture was dynamically mixed in a twin-screw extruder at a speed of 45 r / min for 10 minutes to obtain a dynamically vulcanized mixture; Molding and cooling: After the dynamically vulcanized mixture is extruded through an extruder, it is placed in a low temperature environment of -65°C for rapid cooling to obtain an ultra-cold-resistant sheath material.

[0023] Test results: The material exhibits excellent impact resistance in low temperature environments, with a tensile strength of 20 MPa, an elongation at break of 280%, and a flame retardant performance of UL94 V-0.

[0024] Embodiment 3: A super cold-resistant sheath material for high-speed locomotive cables, comprising the following raw material components in parts by weight: Polyethylene (PE): 50 parts; Ethylene-vinyl acetate copolymer (EVA, vinyl acetate unit content is 45wt%): 25 parts; Polypropylene elastomer (PBE): 5 parts; Mixing aid (1:1 mixture of silicone oil and low molecular weight polydimethylsiloxane): 6 parts; Mixed flame retardant (a 3:2 mixture of aluminum hydroxide and magnesium hydroxide): 14 parts; Mixed antioxidant (1:1 mixture of hindered phenols and phosphites): 2.5 parts; Nano silicon dioxide: 3.5 parts; Dicumyl peroxide (DCP): 2 parts.

[0025] The preparation method is as follows: Pretreatment of nano-modified filler: nano-silica is placed in an ethanol solution of silane coupling agent KH-550, stirred evenly, and dried at 120° C. for 3 hours to obtain a pretreated nano-modified filler; Raw material mixing: PE, EVA, PBE, mixing aids, mixed flame retardants, mixed antioxidants and pretreated nano-modified fillers are added into a twin-screw extruder in proportion, and melt-blended at a temperature of 190° C. to obtain a primary mixture; Dynamic vulcanization: DCP was added to the primary mixture, and the mixture was dynamically mixed in a twin-screw extruder at a speed of 40 r / min for 12 minutes to obtain a dynamically vulcanized mixture; Molding and cooling: After the dynamically vulcanized mixture is extruded through an extruder, it is placed in a low temperature environment of -60°C for rapid cooling to obtain an ultra-cold-resistant sheath material.

[0026] Test results: The material has stable performance in an environment of -65°C, with a tensile strength of 22 MPa, an elongation at break of 290%, and excellent aging resistance.

[0027] Comparative Example 1: The difference from Example 1 is that the amount of the nano-modified filler is reduced to 0, the other components and their amounts remain unchanged, and the preparation method is the same.

[0028] Comparative Example 2: The difference from Example 1 is that the amount of the cold-resistant auxiliary agent is reduced to 0, the other components and their amounts remain unchanged, and the preparation method is the same.

[0029] Comparative Example 3: The difference from Example 1 is that the amount of the cross-linking agent is reduced to 0, the other components and their amounts remain unchanged, and the preparation method is the same.

[0030] The performance test of the super cold-resistant sheath materials of high-speed locomotive cables of Examples 1-3 and Comparative Examples 1-3 was carried out, and the results are shown in Table 1 below: Table 1: Test result analysis: Comparative Example 1: The absence of nano-modified fillers significantly reduced the tensile strength and elongation at break of the material, and both the flame retardant and cold resistance properties decreased, demonstrating the importance of nano-modified fillers in the formula.

[0031] Comparative Example 2: The lack of cold-resistant additives significantly reduces the flexibility of the material in a low-temperature environment, reduces the elongation at break, and the cold-resistant performance is insufficient, indicating the important role of cold-resistant additives in improving the low-temperature flexibility of materials.

[0032] Comparative Example 3: The lack of a cross-linking agent significantly reduces the mechanical properties and flame retardant properties of the material, reduces the elongation at break, and micro-cross-linking has a significant effect on improving the performance.

[0033] By comparing the performance data of the embodiments and the comparative examples, it can be seen that the raw materials in the inventive formula have a synergistic effect, especially the nano-modified filler, cold-resistant additive and cross-linking agent, which play a vital role in improving the comprehensive performance of the material.

[0034] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A super cold-resistant sheath material for high-speed locomotive cables, characterized in that: The super cold-resistant sheath material comprises the following raw material components in parts by mass: 60-80 parts of base polymer; 5-15 parts of toughening agent; 3-10 parts of cold-resistant additives; Flame retardant 10-20 parts; 1-5 parts of antioxidants; 3-10 parts of nano-modified filler; 1-5 parts of crosslinking agent.

2. The ultra-cold-resistant sheath material for high-speed locomotive cables according to claim 1 is characterized in that: The matrix polymer is selected from one of polyethylene and ethylene-vinyl acetate copolymer or a combination of at least two thereof.

3. The ultra-cold-resistant sheath material for high-speed locomotive cables according to claim 1 is characterized in that: The toughening agent is selected from any one of a maleic anhydride grafted compatibilizer, a styrene-butadiene-styrene block copolymer, and a polypropylene elastomer.

4. The ultra-cold-resistant sheath material for high-speed locomotive cables according to claim 1 is characterized in that: The cold-resistant auxiliary agent is selected from silicone oil, low molecular weight polydimethylsiloxane, or a combination of at least two thereof; wherein the low molecular weight polydimethylsiloxane refers to polydimethylsiloxane with a molecular weight less than 10,000.

5. The ultra-cold-resistant sheath material for high-speed locomotive cables according to claim 1 is characterized in that: The flame retardant is selected from one of aluminum hydroxide and magnesium hydroxide or a combination of at least two of them.

6. The ultra-cold-resistant sheath material for high-speed locomotive cables according to claim 1, characterized in that: The antioxidant is selected from one or a combination of at least two of hindered phenol antioxidants and phosphite antioxidants.

7. The ultra-cold-resistant sheath material for high-speed locomotive cables according to claim 1 is characterized in that: The nano-modified filler is selected from any one of nano-silicon dioxide and nano-montmorillonite.

8. The method for preparing the ultra-cold-resistant sheath material for high-speed locomotive cables according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: Placing the nano-modified filler in a coupling agent solution, stirring evenly, and then performing high-temperature drying to obtain a pre-treated nano-modified filler; wherein the coupling agent is a silane coupling agent; Adding the base polymer, the toughening agent, the cold-resistant additive, the flame retardant, the antioxidant and the pretreated nano-modified filler into a twin-screw extruder and blending them at a preset melting temperature to obtain a primary mixture; Adding a crosslinking agent to the primary mixture, and mixing the primary mixture and the crosslinking agent under preset dynamic mixing conditions to obtain a dynamically vulcanized mixture; wherein the crosslinking agent is selected from any one of dicumyl peroxide and di-tert-butyl peroxycumene; After the dynamically vulcanized mixture is extruded and formed by an extruder, it is placed in a preset low-temperature environment for rapid cooling to obtain an ultra-cold-resistant sheath material.

9. The preparation method according to claim 8, characterized in that: The preset melting temperature is 170°C to 220°C, and the preset low temperature environment is -60°C to -80°C.

10. The preparation method according to claim 8, characterized in that: The preset dynamic mixing conditions are a rotation speed of 30-60 r / min and continuous mixing for 5-15 min.

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