Double-layer synergetic low-smoke halogen-free flexible cable

Abstract

The invention discloses a double-layer synergistic low-smoke halogen-free flexible cable which comprises a cable conductor, a low-smoke halogen-free polyolefin insulating layer, a shielding layer and a TPU sheath layer which are sequentially coated from inside to outside, the shore A hardness of the low-smoke halogen-free polyolefin insulating layer is 60-70, and the shore A hardness of the TPU sheath layer is 80-90; the double-layer synergistic low-smoke halogen-free flexible cable realizes the full-structure low-smoke halogen-free characteristic based on the coordination of the insulating layer and the sheath layer, has better flexibility, wear resistance and weather resistance, and can be stably used for a long time under severe conditions such as frequent bending, friction or long-term exposure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric wire and cable, in particular to a double-layer synergic low-smoke halogen-free soft cable. BACKGROUND

[0002] The cable is a kind of electric energy or signal transmission device, usually containing conductor, insulation layer, shielding layer and sheath layer structure, the insulation layer is used to cover the conductor to play the role of insulation, the outermost layer of the cable is the sheath layer, which is used to protect the inner layer from external factors. The traditional cable has the following defects: 1) The insulation layer and sheath layer of the traditional cable are mostly made of PVC material, which will produce a large amount of smoke and toxic halides when burning, posing a great threat to personnel life and property, and are not suitable for strict fire-fighting places such as high-rise buildings and subway tunnels; 2) The traditional cable usually has some shortcomings in softness, wear resistance and weather resistance, and is easily damaged in harsh environments such as frequent bending, friction or long-term exposure, with short service life. SUMMARY

[0003] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a double-layer synergic low-smoke halogen-free soft cable, which realizes the low-smoke halogen-free characteristics of the whole structure based on the synergy of the insulation layer and the sheath layer, and has better softness, wear resistance and weather resistance, and can be used stably for a long time under harsh conditions such as frequent bending, friction or long-term exposure.

[0004] The double-layer synergic low-smoke halogen-free soft cable of the present application is realized by the following technical scheme: A double-layer synergic low-smoke halogen-free soft cable, comprising cable conductor, low-smoke halogen-free polyolefin insulation layer, shielding layer and TPU sheath layer covered in turn from inside to outside, the Shore A hardness of the low-smoke halogen-free polyolefin insulation layer is 60-70, and the Shore A hardness of the TPU sheath layer is 80-90.

[0005] Further, the low-smoke halogen-free polyolefin insulation layer is prepared by the following components with weight percentage: Polyolefin resin 65-80%, flexible agent 5-10%, halogen-free flame retardant 15-20%.

[0006] Further, the polyolefin resin is a blend of EVA resin and POE resin, the VA content in the EVA resin is 28-33%, and the mass ratio of EVA resin to POE resin is (1.5-3):1.

[0007] Further, the flexible agent is epoxidized soybean oil.

[0008] Further, the halogen-free flame retardant of the low-smoke halogen-free polyolefin insulation layer comprises magnesium hydroxide and zinc hydroxyl stannate, and the mass ratio of magnesium hydroxide to zinc hydroxyl stannate is (2.2-3.6):1.

[0009] Further, the TPU sheath layer is prepared by using the following components in percentage by weight: TPU resin 60-75%, reinforcing fiber 10-20%, wear-resistant filler 5-15%, antioxidant 0.2-0.5%, lubricant 0.5-1%, and halogen-free flame retardant 5-10%.

[0010] Further, the TPU resin is thermoplastic polyurethane; and the wear-resistant filler is one or more of silicon carbide, aluminum oxide, and silicon dioxide.

[0011] Further, the reinforcing fiber is one or more of glass fiber, carbon fiber, and aramid fiber; the reinforcing fiber is pretreated by plasma and is cut to 0.2-0.8 mm.

[0012] Further, the halogen-free flame retardant of the TPU sheath layer comprises microencapsulated red phosphorus and magnesium hydroxide, and the mass ratio of microencapsulated red phosphorus to magnesium hydroxide is (0.5-0.7):1; the microencapsulated red phosphorus has a particle size of 5-10 μm and is coated with a silane coupling agent on the surface.

[0013] Further, the lubricant comprises silicone and zinc stearate, and the mass ratio of silicone to zinc stearate is (1-1.5):1; and 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).

[0014] Compared with the prior art, the present application has the following advantages: The double-layer synergistic low-smoke halogen-free flexible cable provided by the present application has a low-smoke halogen-free polyolefin insulation layer, and the polyolefin insulation layer produces less smoke and no toxic halide when burning, compared with a traditional PVC insulation layer; the TPU sheath layer produces less smoke and no toxic halide when burning, compared with a traditional PVC sheath layer; the TPU sheath layer has advantages in wear resistance and weather resistance, compared with the traditional PVC sheath layer; the polyolefin insulation layer has a Shore A hardness of 60-70, has super flexibility, and can closely fit the deformation of the cable conductor and absorb the bending stress of the conductor; and the Shore A hardness of the TPU sheath layer is 80-90, which is in a range that balances rigidity and flexibility, and can adapt to frequent bending use scenarios and balance wear resistance and external load dispersion performance.

[0015] From the above, the double-layer synergistic low-smoke halogen-free soft cable of the present application realizes the low-smoke halogen-free characteristics of the whole structure based on the cooperation of the insulation layer and the sheath layer, and has better softness, wear resistance and weather resistance, and can be used stably for a long time under harsh conditions such as frequent bending, friction or long-term exposure. DETAILED DESCRIPTION

[0016] In the following, the present 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.

[0017] The embodiment of the present application provides a double-layer synergistic low-smoke halogen-free soft cable. The double-layer synergistic low-smoke halogen-free soft cable comprises a cable conductor, a low-smoke halogen-free polyolefin insulation layer, a shielding layer and a TPU sheath layer which are sequentially covered from inside to outside, the Shore A hardness of the low-smoke halogen-free polyolefin insulation layer is 60-70, and the Shore A hardness of the TPU sheath layer is 80-90. The cable conductor plays a role in transmitting power or signals, the low-smoke halogen-free polyolefin insulation layer plays a role in insulation, the shielding layer is used to improve the anti-interference ability and electromagnetic shielding performance of the cable, and the TPU sheath layer plays a role in isolating the external environment to protect the inner layer structure.

[0018] The Shore A hardness of the low-smoke halogen-free polyolefin insulation layer is selected to be 60-70, so that the insulation layer has super-soft characteristics and can closely fit the cable conductor to deform and absorb the bending stress of the conductor. The Shore A hardness of the TPU sheath layer is selected to be 80-90, which is in the interval of considering rigidity and flexibility, and can adapt to the use scene of frequent bending, and also can consider wear resistance and the performance of dispersing external load.

[0019] In the double-layer synergistic low-smoke halogen-free soft cable of the embodiment of the present application, the low-smoke halogen-free polyolefin insulation layer is prepared by using the following components in weight percentage: Polyolefin resin 65-80%, flexible agent 5-10%, halogen-free flame retardant 15-20%. Specifically, the polyolefin resin uses a blend of EVA resin and POE resin, the VA content in the EVA resin is 28-33%, and the mass ratio of the EVA resin to the POE resin is (1.5-3):1. The EVA resin used in this embodiment has better dispersing force, which helps the uniform dispersion of the halogen-free flame retardant, and the POE resin has lower hardness than the EVA resin, which can improve the softness; therefore, the polyolefin resin uses a blend of EVA resin and POE resin, which can consider the dispersion of the flame retardant and the improvement of the softness.

[0020] In the double-layer synergistic low-smoke halogen-free soft cable of the embodiment of the present application, the flexible agent uses epoxidized soybean oil (ESO), which has the advantage of green environmental protection.

[0021] In the double-layer synergistic low-smoke halogen-free soft cable of the embodiment of the present application, the components of the halogen-free flame retardant of the low-smoke halogen-free polyolefin insulation layer comprise magnesium hydroxide and zinc hydroxyl stannate, and the mass ratio of the magnesium hydroxide to the zinc hydroxyl stannate is (2.2~3.6):1. The zinc hydroxyl stannate and the magnesium hydroxide synergistically achieve long-acting flame retardation, the decomposition temperature of the zinc hydroxyl stannate is lower than that of the magnesium hydroxide, temperature gradient control can prolong the flame retardation time, the zinc hydroxyl stannate has the effect of inhibiting smoke, and the magnesium hydroxide can dehydrate and absorb heat, thereby achieving excellent flame-retardant and smoke-inhibiting effects.

[0022] The preferable ratio of the components of the low-smoke halogen-free polyolefin insulation layer of the embodiment of the present application can refer to the following schemes: Scheme 1: polyolefin resin 75% (EVA resin 50%+POE resin 25%); flexibility agent 8%; halogen-free flame retardant 17% (magnesium hydroxide 12%+zinc hydroxyl stannate 5%); Scheme 2: polyolefin resin 70% (EVA resin 50%+POE resin 20%); flexibility agent 10%; halogen-free flame retardant 20% (magnesium hydroxide 14%+zinc hydroxyl stannate 6%).

[0023] The low-smoke halogen-free polyolefin insulation layer of the embodiment of the present application can be prepared by using common process flows such as banburying, granulating, extruding, water cooling and solidifying.

[0024] In the double-layer synergistic low-smoke halogen-free soft cable of the embodiment of the present application, the TPU sheath layer is prepared by using the following components with the weight percentage: TPU resin 60~75%, reinforcing fiber 10~20%, wear-resistant filler 5~15%, antioxidant 0.2~0.5%, lubricant 0.5~1% and halogen-free flame retardant 5~10%. The TPU resin is thermoplastic polyurethane; the wear-resistant filler is one or more of silicon carbide, aluminum oxide or silicon dioxide. Specifically, the wear-resistant filler, the reinforcing fiber and the like can possibly improve the hardness of the sheath layer, and therefore the Shore A hardness of the TPU resin can be selected as 80~85, with the purpose of leaving a certain buffering space.

[0025] In the double-layer synergistic low-smoke halogen-free soft cable of the embodiment of the present application, the reinforcing fiber is one or more of glass fiber, carbon fiber or aramid fiber; the reinforcing fiber is pretreated by plasma and is cut short to 0.2~0.8mm. The reinforcing fiber is used to improve the tensile strength and tear resistance of the TPU sheath layer, and the fiber length is moderate, which does not easily cause low reinforcing efficiency due to ineffective stress transmission caused by being too short, and does not easily cause aggregation during processing, thereby causing internal defects of the sheath layer; after the plasma treatment, the strong combination of the fiber and the TPU matrix can inhibit the expansion of micro-cracks, the enhanced interface combination can improve the performance retention rate of the TPU sheath layer in a humid heat environment, and the weather resistance is improved.

[0026] In the double-layer synergistic low-smoke halogen-free soft cable of the embodiment of the present application, the halogen-free flame retardant of the TPU sheath layer comprises microencapsulated red phosphorus and magnesium hydroxide, and the mass ratio of the microencapsulated red phosphorus to the magnesium hydroxide is (0.5-0.7):1; wherein the particle size of the microencapsulated red phosphorus is 5-10 μm, and the surface is coated with silane coupling agent. When the particle size is <5 μm, it is easy to agglomerate, which can cause uneven dispersion; when the particle size is >10 μm, the specific surface area is insufficient, and the release rate of phosphorus is slow; therefore, the particle size is 5-10 μm, which takes into account uniform dispersion and release rate, and improves the flame retardant performance. The traditional flame retardant can easily cause a significant decrease in the tensile strength of the sheath layer after being added, however, the red phosphorus coated with silane coupling agent can improve the compatibility with the TPU matrix, which can effectively reduce the decrease in the tensile strength caused by the addition of the flame retardant, and realize the balance between the tensile strength and the flame retardant performance. The microencapsulated red phosphorus and the magnesium hydroxide can synergistically improve the oxygen index, the microcapsule structure can inhibit the oxidation of red phosphorus to generate PH3 and other toxic gases, and the microcapsule structure can also delay the hydrolysis of red phosphorus, improve the performance retention rate in a humid and hot environment, and improve the weather resistance.

[0027] In the double-layer synergistic low-smoke halogen-free soft cable of the embodiment of the present application, the lubricant comprises silicone and zinc stearate, and the mass ratio of the silicone to the 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.

[0028] In the double-layer synergistic low-smoke halogen-free soft cable of the embodiment of the present application, the antioxidant comprises hindered phenolic antioxidant 1010 and 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 the thermal oxygen stability and effectively improve the weather resistance.

[0029] The preferred ratio of the components of the TPU sheath layer of the embodiment of the present application can refer to the following schemes: Scheme 1: TPU resin 70%, aramid fiber 12%, silicon carbide 9%, antioxidant 0.3% (1010 / 168=1:2), lubricant 0.7% (silicone 0.4%+zinc stearate 0.3%), halogen-free flame retardant 8% (microencapsulated red phosphorus 3%+magnesium hydroxide 5%); Scheme 2: TPU resin 65%, aramid fiber 12%, carbon fiber 6%, silicon carbide 6%, antioxidant 0.4% (1010 / 168=1:2), lubricant 0.6% (silicone 0.3%+zinc stearate 0.3%), halogen-free flame retardant 10% (microencapsulated red phosphorus 4%+magnesium hydroxide 6%).

[0030] The preparation of the TPU sheath layer of the embodiment of the present application can adopt common process flows such as banburying granulation, extruder extrusion, water cooling solidification, etc.

[0031] In summary, the double-layer synergistic low-smoke halogen-free soft cable of the present application realizes the low-smoke halogen-free characteristics of the whole structure based on the synergy of the insulation layer and the sheath layer, and has better softness, wear resistance and weather resistance, and can be used stably for a long time under harsh conditions such as frequent bending, friction or long-term exposure.

[0032] The above-mentioned embodiments are only preferred embodiments of the present application, and cannot be used to limit the protection scope of the present application, and any non-essential changes and replacements made by those skilled in the art on the basis of the present application shall fall within the protection scope of the present application.

Claims

1. A double-layer coordinated low-smoke halogen-free flexible cable, characterized in that: The cable comprises a cable conductor, a low-smoke halogen-free polyolefin insulation layer, a shielding layer and a TPU sheath layer which are sequentially coated from the inside to the outside. The Shore A hardness of the low-smoke halogen-free polyolefin insulation layer is 60-70, and the Shore A hardness of the TPU sheath layer is 80-90.

2. The double-layer cooperative low-smoke zero-halogen flexible cable according to claim 1, characterized in that: The low-smoke halogen-free polyolefin insulation layer is prepared using the following components in percentage by weight: Polyolefin resin 65~80%, flexible agent 5~10%, halogen-free flame retardant 15~20%.

3. The double-layer cooperative low-smoke zero-halogen flexible cable according to claim 2, characterized in that: The polyolefin resin is a blend of EVA resin and POE resin, the VA content in the EVA resin is 28-33%, and the mass ratio of the EVA resin to the POE resin is (1.5-3):

1.

4. The double-layer cooperative low-smoke zero-halogen flexible cable according to claim 2, characterized in that: The softener is epoxidized soybean oil.

5. The double-layer cooperative low-smoke zero-halogen flexible cable according to claim 2, characterized in that: The components of the halogen-free flame retardant of the low-smoke halogen-free polyolefin insulation layer include magnesium hydroxide and zinc hydroxystannate, and the mass ratio of magnesium hydroxide to zinc hydroxystannate is (2.2-3.6):

1.

6. The double-layer coordinated low-smoke zero-halogen flexible cable according to claim 1, characterized in that: The TPU sheath layer is prepared using the following components in percentage by weight: TPU resin 60~75%, reinforcing fiber 10~20%, wear-resistant filler 5~15%, antioxidant 0.2~0.5%, lubricant 0.5~1% and halogen-free flame retardant 5~10%.

7. The double-layer coordinated low-smoke zero-halogen flexible cable according to claim 6, characterized in that: The TPU resin is thermoplastic polyurethane; the wear-resistant filler is one or more of silicon carbide, aluminum oxide or silicon dioxide.

8. The double-layer coordinated low-smoke zero-halogen flexible cable according to claim 6, characterized in that: The reinforcing fibers are one or more of glass fibers, carbon fibers, or aramid fibers; the reinforcing fibers are plasma pretreated and cut to a length of 0.2 to 0.8 mm.

9. The double-layer coordinated low-smoke zero-halogen flexible cable according to claim 6, characterized in that: The halogen-free flame retardant of the TPU sheath layer comprises components including microencapsulated red phosphorus and magnesium hydroxide, and the mass ratio of the microencapsulated red phosphorus to the magnesium hydroxide is (0.5-0.7):1; wherein the particle size of the microencapsulated red phosphorus is 5-10 μm, and the surface is coated with a silane coupling agent.

10. The double-layer coordinated low-smoke zero-halogen flexible cable according to claim 6, characterized in that: The lubricant comprises silicone and zinc stearate, and the mass ratio of silicone to zinc stearate is (1-1.5):1; the antioxidant comprises hindered phenol antioxidant 1010 and phosphite antioxidant 168, and the mass ratio of hindered phenol antioxidant 1010 to phosphite antioxidant 168 is 1:(1-2).