High-thermal-conductivity bending-resistant TPU (Thermoplastic Polyurethane) sheathed cable and manufacturing process thereof

Abstract

The invention discloses a high-thermal-conductivity bending-resistant TPU (thermoplastic polyurethane) sheathed cable and a manufacturing process thereof, the cable comprises a cable conductor, an insulating layer, a shielding layer and a sheath layer which are sequentially coated from inside to outside, and the sheath layer is prepared from the following components in percentage by weight: 60-75% of TPU resin, 20-35% of hexagonal boron nitride, 1.5-4% of two-dimensional graphene oxide, 0.5-2% of a chain extender, 1.5-3.5% of a coupling agent, 1-3% of a lubricant and 0.3-1% of an antioxidant; wherein the mass ratio of the hexagonal boron nitride to the two-dimensional graphene oxide is (6-12): 1. According to the high-thermal-conductivity bending-resistant TPU sheath cable and the manufacturing process thereof, the requirements of rail transit high-voltage cables, robot flexible cables and other scenes needing high heat dissipation performance and bending resistance can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric wire and cable, in particular to a high-thermal-conductivity and bend-resistant TPU sheath cable and a manufacturing process thereof, which is suitable for high-voltage cables for rail transit, flexible cables for robots and other scenarios requiring high heat dissipation and bend resistance. BACKGROUND

[0002] With the rapid development of industrial automation, rail transit and other fields, the requirements for cable performance are also becoming higher and higher. The cable is a kind of power or signal transmission device, which usually contains conductor, insulation layer, shielding layer and sheath layer. The insulation layer is used to cover the conductor to play an insulating role. The outermost layer of the cable is the sheath layer, which is used to protect the inner layer from external factors, and is a key factor to ensure the service life and safety of the cable.

[0003] The traditional PVC cable sheath has the problems of poor thermal conductivity and low-temperature embrittlement. When the cable is running, the conductor generates heat. If the sheath has poor thermal conductivity, the heat will accumulate, causing the internal temperature to continuously rise, accelerating the breakage of the high molecular chain of the insulation layer, and causing insulation failure. In addition, although single boron nitride or graphene can be added to improve the thermal conductivity, it is easy to cause the cable sheath to have a large increase in rigidity and a large decrease in bend resistance. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a high-thermal-conductivity and bend-resistant TPU sheath cable and a manufacturing process thereof, which can meet the requirements of high-voltage cables for rail transit, flexible cables for robots and other scenarios requiring high heat dissipation and bend resistance.

[0005] The high-thermal-conductivity and bend-resistant TPU sheath cable of the present application is realized by the following technical scheme: A high-thermal-conductivity and bend-resistant TPU sheath cable, which comprises a cable conductor, an insulation layer, a shielding layer and a sheath layer covered in turn from the inside to the outside, wherein the sheath layer is prepared from the following components by weight percentage: TPU resin 60-75%, hexagonal boron nitride 20-35%, two-dimensional graphene oxide 1.5-4%, chain extender 0.5-2%, coupling agent 1.5-3.5%, lubricant 1-3%, antioxidant 0.3-1%; wherein the mass ratio of hexagonal boron nitride to two-dimensional graphene oxide is (6-12):1.

[0006] Further, the chain extender is one or more of 1,4-butanediol, ethylene glycol or trimethylolpropane.

[0007] Further, the coupling agent is one or more of silane coupling agent KH550, silane coupling agent KH560 or titanate coupling agent NDZ-201.

[0008] Further, the lubricant comprises silicone and zinc stearate, and the mass ratio of the silicone and the zinc stearate is (1-1.5):1.

[0009] Further, the antioxidant comprises hindered phenolic antioxidant 1010 and phosphite antioxidant 168, and the mass ratio of the hindered phenolic antioxidant 1010 and the phosphite antioxidant 168 is 1:(1-2).

[0010] Further, the hexagonal boron nitride and the two-dimensional graphene oxide are made into the composite heat-conducting material through the following pretreatment steps: (a) dispersing hexagonal boron nitride nanosheets with a particle size of 10-50 nm and two-dimensional graphene oxide with a monolayer thickness of 1 nm in an organic solvent at a mass ratio of (6-12):1 to form a 3-5 wt% suspension; (b) ultrasonic treatment for 40-60 min, and after freeze-drying, heat treatment at 450-550 DEG C for 1.5-3 hours to form a hexagonal boron nitride / two-dimensional graphene oxide composite heat-conducting material.

[0011] The manufacturing process of the high-heat-conducting and bend-resistant TPU sheath cable of the present application adopts the following technical scheme: The manufacturing process of the high-heat-conducting and bend-resistant TPU sheath cable as described above comprises the following steps: S1, preparing a cable conductor; S2, preparing a single-core or multi-core insulated conductor, the single-core insulated conductor being obtained by coating an insulating layer on the outer side of a single cable conductor, and the multi-core insulated conductor being obtained by twisting a plurality of single-core insulated conductors; S3, braiding a shielding layer and coating the shielding layer on the outer side of the single-core or multi-core insulated conductor to obtain a cable core; S4, preparing a TPU sheath layer and coating the TPU sheath layer on the outer side of the cable core.

[0012] Further, step S4 comprises: S4-1: adding TPU resin, chain extender, coupling agent, lubricant, antioxidant and hexagonal boron nitride / two-dimensional graphene oxide composite heat-conducting material into a banbury mixer, and mixing at 160-180 DEG C and 40-60 rpm; S4-2: discharging the banbury mixer into a granulator for granulation, and vacuum drying the discharge of the granulator to obtain TPU granular material; S4-3: adding the TPU granular material into an extruder to prepare a TPU sheath layer, and performing vacuum sizing adsorption, water cooling and traction winding on the discharge of the extruder to coat the TPU sheath layer on the outer side of the cable core.

[0013] Compared with the prior art, the present application has the following advantages: The high-thermal-conductivity and bending-resistant TPU sheath cable and the manufacturing process thereof provided by the application break through the thermal conductivity while maintaining the flexibility of TPU, fill the technical gap of high-flexibility and high-thermal-conductivity cable sheath, and can meet the needs of high-thermal-conductivity and bending-resistant scenarios such as rail transit high-voltage cables and robot flexible cables. DETAILED DESCRIPTION

[0014] Hereinafter, the application will be further described in conjunction with specific embodiments, and it should be noted that the embodiments described below or the technical features thereof can be combined in any manner to form new embodiments without conflict.

[0015] The application provides a high-thermal-conductivity and bending-resistant TPU sheath cable and a manufacturing process thereof. The high-thermal-conductivity and bending-resistant TPU sheath cable comprises, from inside to outside, a cable conductor, an insulation layer, a shielding layer and a sheath layer, and the sheath layer is prepared from the following components by weight percentage: TPU resin 60-75%, hexagonal boron nitride 20-35%, two-dimensional graphene oxide 1.5-4%, chain extender 0.5-2%, coupling agent 1.5-3.5%, lubricant 1-3%, antioxidant 0.3-1%; wherein the mass ratio of hexagonal boron nitride to two-dimensional graphene oxide is (6-12):1. The TPU resin is thermoplastic polyurethane, which has excellent elasticity and weather resistance.

[0016] In the high-thermal-conductivity and bending-resistant TPU sheath cable of the application, the chain extender is one or more of 1,4-butanediol, ethylene glycol or trimethylolpropane. During processing, the hexagonal boron nitride / two-dimensional graphene oxide filler is easy to cut the TPU molecular chain, resulting in a decrease in elongation at break, so the chain extender is needed to repair the loss of molecular chain, and the chain extender can also control the spacing of crosslinking points to avoid excessive crosslinking leading to a sharp increase in elastic modulus. Therefore, it helps to ensure the flexibility in the case of high filler, and further ensures the bending resistance.

[0017] In the high-thermal-conductivity and bending-resistant TPU sheath cable of the application, the coupling agent is one or more of silane coupling agent KH550, silane coupling agent KH560 or titanate coupling agent NDZ-201.

[0018] In the high-thermal-conductivity and bending-resistant TPU sheath cable of the application, the lubricant contains silicone and zinc stearate, and the mass ratio of silicone to zinc stearate is (1-1.5):1. The lubricant is used to improve the processing performance, including reducing the friction between the melt and the processing equipment, and reducing the friction between the molecular chains, which can improve the melt flowability, reduce the extrusion pressure of the TPU sheath, and make the discharge surface free of sharkskin defects.

[0019] In the high-thermal-conductivity and bending-resistant TPU sheath cable of the embodiment of the present application, the antioxidant comprises a hindered phenolic antioxidant 1010 and a phosphite antioxidant 168, and the mass ratio of the hindered phenolic antioxidant 1010 to the phosphite antioxidant 168 is 1:(1-2). The antioxidant can effectively enhance thermal oxygen stability and improve weather resistance.

[0020] The preferred ratio of the components of the sheath layer of the high-strength and wear-resistant TPU sheath cable of the embodiment can refer to the following scheme.

[0021] Scheme 1: TPU resin 62%, hexagonal boron nitride 30%, two-dimensional graphene oxide 2.5%, chain extender 1.2% (1,4-butanediol), coupling agent 2% (KH550), lubricant 1.8% (the mass ratio of silicone to zinc stearate is 1:1), antioxidant 0.5% (the mass ratio of hindered phenolic antioxidant 1010 to phosphite antioxidant 168 is 1:1).

[0022] Scheme 2: TPU resin 68%, hexagonal boron nitride 23%, two-dimensional graphene oxide 2.5%, chain extender 1.5% (trimethylolpropane), coupling agent 2.5% (NDZ-201), lubricant 2% (the mass ratio of silicone to zinc stearate is 1:1), antioxidant 0.5% (the mass ratio of hindered phenolic antioxidant 1010 to phosphite antioxidant 168 is 1:1).

[0023] In the high-thermal-conductivity and bending-resistant TPU sheath cable of the embodiment of the present application, the hexagonal boron nitride and the two-dimensional graphene oxide are made into a composite thermal conductive material through the following pretreatment steps: (a) dispersing hexagonal boron nitride nanosheets with a particle size of 10-50 nm and two-dimensional graphene oxide with a monolayer thickness of 1 nm in an organic solvent at a mass ratio of (6-12):1 to form a 3-5 wt% suspension; (b) ultrasonic treatment for 40-60 min, and after freeze-drying, heat treatment at 450-550°C for 1.5-3 hours to form a hexagonal boron nitride / two-dimensional graphene oxide composite thermal conductive material.

[0024] During the freeze-drying process, ice crystals grow along the axial direction and expand the layers of hexagonal boron nitride / two-dimensional graphene oxide, forming a three-dimensional through network, greatly improving the porosity, and further greatly improving the thermal conductive path density, that is, the thermal conductive performance.

[0025] The manufacturing process of the high-thermal-conductivity and bending-resistant TPU sheath cable of the embodiment of the present application comprises the following steps S1-S4.

[0026] S1, preparing a cable conductor; S2, preparing a single-core or multi-core insulated conductor, the single-core insulated conductor being obtained by coating an outer side of a single cable conductor with an insulating layer, and the multi-core insulated conductor being obtained by twisting a plurality of single-core insulated conductors; S3, braiding a shielding layer and coating an outer side of the single-core or multi-core insulated conductor to obtain a cable core; S4, preparing a TPU sheath layer and coating an outer side of the cable core.

[0027] The step S4 comprises: S4-1, adding TPU resin, chain extender, coupling agent, lubricant, antioxidant, and hexagonal boron nitride / two-dimensional graphene oxide composite heat-conducting material into a mixing mill (for example, a Banbury type mixing mill), and mixing at 160-180 DEG C and 40-60 rpm; S4-2, discharging the mixing mill into a granulator (for example, a double screw granulator) to cut the particles, and performing vacuum drying treatment on the discharge of the granulator to obtain TPU granular material; S4-3, adding the TPU granular material into an extruder (for example, a two-stage co-rotating double screw extruder) to prepare a TPU sheath layer, and performing vacuum sizing adsorption, water cooling shaping and traction winding on the discharge of the extruder to coat the TPU sheath layer on the outer side of the cable core.

[0028] In summary, the high-heat-conducting and bend-resistant TPU sheath cable and the manufacturing process thereof provided by the embodiments of the present application can break through the heat-conducting performance while maintaining the flexibility of TPU, fill the technical gap of high-flexibility and high-heat-conducting cable sheath, and meet the needs of high-heat-dissipation and bend-resistance in scenarios such as rail transit high-voltage cables and robot flexible cables.

[0029] The above embodiments are only preferred embodiments of the present application, and cannot be used to limit the scope of protection of the present application. Any non-substantial changes and replacements made by those skilled in the art on the basis of the present application are within the scope of protection of the present application.

Claims

1. A high thermal conductivity and bend-resistant TPU sheathed cable, characterized in that, The cable comprises, from the inside out, a cable conductor, an insulation layer, a shielding layer, and a sheath layer, wherein the sheath layer is prepared using the following components in weight percentage: The composition of TPU resin is 60-75%, hexagonal boron nitride is 20-35%, two-dimensional graphene oxide is 1.5-4%, chain extender is 0.5-2%, coupling agent is 1.5-3.5%, lubricant is 1-3%, and antioxidant is 0.3-1%. The mass ratio of hexagonal boron nitride to two-dimensional graphene oxide is (6-12):

1.

2. The high thermal conductivity and bend-resistant TPU sheathed cable as described in claim 1, characterized in that, The chain extender is one or more of 1,4-butanediol, ethylene glycol, or trimethylolpropane.

3. The high thermal conductivity and bend-resistant TPU sheathed cable as described in claim 1, characterized in that, The coupling agent is one or more of the following: silane coupling agent KH550, silane coupling agent KH560, or titanate coupling agent NDZ-201.

4. The high thermal conductivity and bend-resistant TPU sheathed cable as described in claim 1, characterized in that, The lubricant contains silicone and zinc stearate, and the mass ratio of silicone to zinc stearate is (1~1.5):

1.

5. The high thermal conductivity and bend-resistant TPU sheathed cable as described in claim 1, characterized in that, The antioxidant comprises hindered phenolic antioxidant 1010 and phosphite antioxidant 168, and the mass ratio of hindered phenolic antioxidant 1010 to phosphite antioxidant 168 is 1:(1~2).

6. The high thermal conductivity and bend-resistant TPU sheathed cable as described in any one of claims 1 to 5, characterized in that, The hexagonal boron nitride and two-dimensional graphene oxide are processed into a composite thermally conductive material through the following pretreatment steps: (a) Hexagonal boron nitride nanosheets with a particle size of 10-50 nm and two-dimensional graphene oxide with a single layer thickness of 1 nm are dispersed in an organic solvent at a mass ratio of (6-12):1 to form a 3-5 wt% suspension. (b) The material is ultrasonically treated for 40 to 60 minutes and then freeze-dried before being heat-treated at 450 to 550°C for 1.5 to 3 hours to form a hexagonal boron nitride / two-dimensional graphene oxide composite thermal conductive material.

7. A manufacturing process for a high thermal conductivity and bend-resistant TPU sheathed cable as described in claim 6, characterized in that, The manufacturing process includes the following steps: S1. Prepare the cable conductor; S2. Prepare single-core or multi-core insulated conductors. A single-core insulated conductor is obtained by covering the outside of a single cable conductor with an insulation layer, and a multi-core insulated conductor is obtained by stranding multiple single-core insulated conductors. S3. A braided shielding layer is wrapped around the outside of a single-core or multi-core insulated conductor to obtain a cable core; S4. Prepare the TPU sheath layer and wrap it around the outside of the cable core.

8. The manufacturing process of the high thermal conductivity and bend-resistant TPU sheathed cable as described in claim 7, characterized in that, Step S4 includes: S4-1: Add TPU resin, chain extender, coupling agent, lubricant, antioxidant, and hexagonal boron nitride / two-dimensional graphene oxide composite thermal conductive material to a mixer and mix them at 160~180℃ and 40~60 rpm. S4-2: The material discharged from the internal mixer enters the granulator for pelletizing. The material discharged from the granulator is then vacuum dried to obtain TPU granular material. S4-3: TPU granules are added to an extruder to prepare a TPU sheath layer. After the TPU sheath layer is discharged from the extruder, it undergoes vacuum sizing adsorption, water cooling shaping, and traction winding to cover the outside of the cable core.