High-temperature-resistant flame-retardant cable

Abstract

The invention relates to the technical field of cables, and provides a high-temperature-resistant flame-retardant cable which sequentially comprises a conductor, an insulating layer and a sheath layer from inside to outside, and the sheath layer is prepared from the following raw materials in parts by weight: 70 parts of a composite polyethylene material, 6-12 parts of polypropylene, 5-10 parts of an ethylene-vinyl acetate copolymer, 10-20 parts of mullite powder, 1-2 parts of an antioxidant, 1-3 parts of a plasticizer and 8-12 parts of a flame retardant; the preparation method of the composite polyethylene material comprises the following steps: A1, uniformly mixing dolomite powder, melamine phosphate and erythritol, and carrying out ball milling to obtain a blend; a2, the blend and polyethylene are blended and extruded, and the composite polyethylene material is obtained. According to the technical scheme, the problem that the flame retardant property of the cable sheath layer is poor in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and more specifically, to a high-temperature resistant and flame-retardant cable. Background Technology

[0002] With the rapid development of industries such as power and communications, the performance requirements of cables, as an important transmission medium, are increasing, especially in the application of cables in harsh environments such as high temperature and flammability.

[0003] Traditional cable sheaths are mostly made of materials such as polyethylene and polyvinyl chloride. While these materials possess a certain level of insulation and mechanical strength, they are prone to decomposition at high temperatures and have relatively poor flame-retardant properties, making it difficult to meet the safety requirements of special applications. To improve the flame-retardant performance of cables, large amounts of flame retardants, such as magnesium hydroxide and aluminum hydroxide, are typically added to the sheath. However, while adding large amounts of flame retardants can enhance the flame-retardant effect, it can also reduce the stability of the internal structure of the sheath, thereby affecting the overall performance and flame-retardant efficiency of the cable sheath.

[0004] Therefore, developing a high-temperature resistant flame-retardant cable that can reduce the amount of flame retardant used while also giving the cable sheath good flame-retardant properties is of great significance for extending the service life of the cable in high-temperature environments and improving its safety performance. Summary of the Invention

[0005] This invention proposes a high-temperature resistant flame-retardant cable, which solves the problem of poor flame-retardant performance of cable sheath layers in related technologies.

[0006] The technical solution of the present invention is as follows: This invention proposes a high-temperature resistant and flame-retardant cable, comprising, from the inside out, a conductor, an insulation layer, and a sheath layer. The raw material of the sheath layer comprises the following components in parts by weight: The composition includes 70 parts of composite polyethylene material, 6-12 parts of polypropylene, 5-10 parts of ethylene-vinyl acetate copolymer, 10-20 parts of mullite powder, 1-2 parts of antioxidant, 1-3 parts of plasticizer, and 8-12 parts of flame retardant. The preparation method of the composite polyethylene material includes the following steps: A1. Mix dolomite powder, melamine phosphate and erythritol evenly, and ball mill to obtain a blend; A2. The blend is blended with polyethylene and extruded to obtain a composite polyethylene material.

[0007] As a further technical solution, the weight ratio of melamine phosphate, erythritol and dolomite powder is 1:1:2 to 5, for example, it can be 1:1:2, 1:1:2.5, 1:1:3, 1:1:3.5, 1:1:4, 1:1:4.5, 1:1:5, preferably 1:1:3 to 4.

[0008] As a further technical solution, the weight ratio of the polyethylene to the dolomite powder is 20:2 to 5, for example, it can be 20:2, 20:2.5, 20:3, 20:3.5, 20:4, 20:4.5, or 20:5, preferably 20:3 to 4.

[0009] As a further technical solution, in step A1, the ball milling speed is 100~200 rpm, for example, 100 rpm, 120 rpm, 140 rpm, 150 rpm, 160 rpm, 180 rpm, 200 rpm, preferably 100 rpm, 160 rpm, 200 rpm, more preferably 160 rpm, and the ball milling time is 20~40 min, for example, 20 min, 25 min, 30 min, 35 min, 40 min, preferably 20 min, 30 min, 40 min, more preferably 30 min.

[0010] As a further technical solution, the raw material of the sheath layer also includes acetaminobenzoic acid.

[0011] As a further technical solution, the amount of para-acetaminobenzoic acid added is 10% to 20% of the weight of mullite powder, for example, it can be 10%, 12%, 14%, 15%, 16%, 18%, or 20%, preferably 14% to 18%.

[0012] As a further technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 330, preferably antioxidant 168.

[0013] As a further technical solution, the plasticizer includes one or more of diisodecyl phthalate, dioctyl adipate, and diisononyl phthalate, preferably diisodecyl phthalate.

[0014] As a further technical solution, the flame retardant includes one or both of magnesium hydroxide and aluminum hydroxide.

[0015] As a further technical solution, the material of the conductor is one of aluminum alloy and copper alloy, preferably aluminum alloy; The insulation layer is a polyvinyl chloride insulation layer.

[0016] This invention also proposes a method for preparing a high-temperature resistant and flame-retardant cable, comprising the following steps: S1. The insulating layer is extruded and wrapped around the outside of the conductor to form an insulating layer; S2. The composite polyethylene material, polypropylene, ethylene-vinyl acetate copolymer, mullite powder, antioxidant, plasticizer, and flame retardant are blended and extruded to coat the outside of the insulation layer to obtain the high-temperature resistant flame-retardant cable.

[0017] This invention also proposes a method for preparing a high-temperature resistant and flame-retardant cable, comprising the following steps: B1. The insulating layer is extruded and wrapped around the outside of the conductor to form an insulating layer; B2. Dissolve acetaminobenzoic acid in ethanol, add mullite powder, disperse evenly, concentrate, and dry to obtain a mixture of mullite powder; B3. A mixture of composite polyethylene material, polypropylene, ethylene-vinyl acetate copolymer, mullite powder, antioxidant, plasticizer, and flame retardant is blended and extruded onto the outside of the insulation layer to obtain the high-temperature resistant flame-retardant cable.

[0018] In the sheath layer of the high-temperature flame-retardant cable of this invention, mullite powder is first mixed with acetaminobenzoic acid, which enhances the interaction between the mullite powder and the components in the sheath layer, thereby forming a more dense and stable sheath layer with a superior internal structure. This effectively improves the mechanical strength of the sheath layer of the high-temperature flame-retardant cable. Furthermore, by optimizing the ratio of acetaminobenzoic acid to mullite powder, when the amount of acetaminobenzoic acid added is 14% to 18% of the weight of the mullite powder, the mechanical strength of the sheath layer of the high-temperature flame-retardant cable can be further improved, achieving a tensile strength of 25.6 to 26.2 MPa.

[0019] As a further technical solution, in step B2, when the dispersion is uniform, it is done by stirring at a speed of 300-500 rpm, such as 300 rpm, 350 rpm, 400 rpm, 450 rpm, or 500 rpm, preferably 400 rpm, and for a stirring time of 30-50 min, such as 30 min, 35 min, 40 min, 45 min, or 50 min, preferably 40 min.

[0020] The working principle and beneficial effects of this invention are as follows: In the sheath layer of the high-temperature flame-retardant cable of this invention, dolomite powder, melamine phosphate, and erythritol are mixed and then blended with polyethylene to obtain a composite polyethylene material. Using this composite material as the main base material of the sheath layer effectively improves the flame-retardant performance of the high-temperature flame-retardant cable sheath layer. Melamine phosphate, erythritol, and polyethylene substrate have good compatibility under high-temperature conditions. Firstly, the blending of melamine phosphate, erythritol, and dolomite powder improves the dispersibility of dolomite powder in the polyethylene substrate. Under high-temperature conditions, melamine phosphate and erythritol can form a carbon layer in the polyethylene substrate. The non-combustible gas generated by the dolomite powder under high-temperature conditions promotes the foaming of the carbon layer, thereby forming a denser carbon layer on the surface. This gives the polyethylene substrate good heat insulation capabilities and reduces, to some extent, the defect of easy decomposition of the polyethylene substrate itself at high temperatures. In the sheath layer of the high-temperature flame-retardant cable of the present invention, composite polyethylene material is used as the base material, combined with polypropylene, ethylene-vinyl acetate copolymer, mullite powder, antioxidant and plasticizer. While reducing the amount of flame retardant in the sheath layer, the sheath layer of the high-temperature flame-retardant cable can also have good flame-retardant performance. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] In the following examples and comparative examples, the polyethylene was DMDA-8008H; melamine phosphate, CAS number 15541-60-3, was purchased from Wuhan Shuer Biotechnology Co., Ltd.; erythritol had an active ingredient content of 99%; the dolomite powder had an average particle size of 10 μm; the ethylene-vinyl acetate copolymer was EVA 150W; the mullite powder had an average particle size of 45 μm; the insulation layer was a polyvinyl chloride insulation layer; and the conductor was an aluminum alloy conductor.

[0023] Example 1 The preparation method of composite polyethylene material includes the following steps: A1. Mix 8 parts dolomite powder, 4 parts melamine phosphate and 4 parts erythritol evenly, and ball mill at 100 rpm for 40 min to obtain a blend; A2. Blend the blend with 80 parts of polyethylene, extrude, and obtain a composite polyethylene material; A high-temperature resistant and flame-retardant cable includes the following steps: S1. The raw material of the insulating layer is extruded and coated on the outside of the aluminum alloy conductor to form a polyvinyl chloride insulating layer; S2. 70 parts of composite polyethylene material, 6 parts of polypropylene, 5 parts of ethylene-vinyl acetate copolymer, 10 parts of mullite powder, 1 part of antioxidant 168, 1 part of diisodecyl phthalate, and 8 parts of magnesium hydroxide are blended and extruded onto the outside of the polyvinyl chloride insulation layer to obtain a high-temperature resistant flame-retardant cable.

[0024] Example 2 The preparation method of composite polyethylene material includes the following steps: A1. Mix 8 parts dolomite powder, 4 parts melamine phosphate and 4 parts erythritol evenly, and ball mill at 160 rpm for 30 min to obtain a blend; A2. Blend the blend with 80 parts of polyethylene, extrude, and obtain a composite polyethylene material; A high-temperature resistant and flame-retardant cable includes the following steps: S1. The raw material of the insulating layer is extruded and coated on the outside of the aluminum alloy conductor to form a polyvinyl chloride insulating layer; S2. 70 parts of composite polyethylene material, 10 parts of polypropylene, 8 parts of ethylene-vinyl acetate copolymer, 20 parts of mullite powder, 1.5 parts of antioxidant 168, 1.5 parts of diisodecyl phthalate, and 10 parts of aluminum hydroxide are blended and extruded onto the outside of the polyvinyl chloride insulation layer to obtain a high-temperature resistant flame-retardant cable.

[0025] Example 3 The preparation method of composite polyethylene material includes the following steps: A1. Mix 8 parts dolomite powder, 4 parts melamine phosphate and 4 parts erythritol evenly, and ball mill at 200 rpm for 20 min to obtain a blend; A2. Blend the blend with 80 parts of polyethylene, extrude, and obtain a composite polyethylene material; A high-temperature resistant and flame-retardant cable includes the following steps: S1. The raw material of the insulating layer is extruded and coated on the outside of the aluminum alloy conductor to form a polyvinyl chloride insulating layer; S2. 70 parts of composite polyethylene material, 12 parts of polypropylene, 10 parts of ethylene-vinyl acetate copolymer, 20 parts of mullite powder, 2 parts of antioxidant 168, 3 parts of diisodecyl phthalate, and 12 parts of aluminum hydroxide are blended and extruded onto the outside of the polyvinyl chloride insulation layer to obtain a high-temperature resistant flame-retardant cable.

[0026] Example 4 The only difference between this embodiment and Embodiment 2 is that in the preparation method of the composite polyethylene material in this embodiment, the amount of dolomite powder added is 12 parts.

[0027] Example 5 The only difference between this embodiment and Embodiment 2 is that in the preparation method of the composite polyethylene material in this embodiment, the amount of dolomite powder added is 16 parts.

[0028] Example 6 The only difference between this embodiment and Embodiment 2 is that in the preparation method of the composite polyethylene material in this embodiment, the amount of dolomite powder added is 20 parts.

[0029] Example 7 The only difference between this embodiment and Embodiment 5 is that the preparation method of the high-temperature resistant flame-retardant cable in this embodiment is different, specifically: B1. The raw material of the insulation layer is extruded and coated on the outside of the aluminum alloy conductor to form a polyvinyl chloride insulation layer; B2. Dissolve 2 parts of acetaminobenzoic acid in 50 parts of ethanol, add 20 parts of mullite powder, stir at 400 rpm for 40 min to disperse evenly, concentrate, and dry to obtain a mullite powder mixture. B3. 70 parts of composite polyethylene material, 10 parts of polypropylene, 8 parts of ethylene-vinyl acetate copolymer, 20 parts of mullite powder mixture, 1.5 parts of antioxidant 168, 1.5 parts of diisodecyl phthalate, and 10 parts of aluminum hydroxide are blended and extruded onto the outside of the polyvinyl chloride insulation layer to obtain a high-temperature resistant flame-retardant cable.

[0030] Example 8 The only difference between this embodiment and Embodiment 7 is that in the preparation method of the high-temperature flame-retardant cable in this embodiment, the amount of acetaminobenzoic acid added is 2.8 parts.

[0031] Example 9 The only difference between this embodiment and Embodiment 7 is that in the preparation method of the high-temperature flame-retardant cable in this embodiment, the amount of acetaminobenzoic acid added is 3.6 parts.

[0032] Example 10 The only difference between this embodiment and Embodiment 7 is that in the preparation method of the high-temperature flame-retardant cable in this embodiment, the amount of acetaminobenzoic acid added is 4 parts.

[0033] Example 11 The only difference between this embodiment and Embodiment 5 is that the preparation method of the high-temperature resistant flame-retardant cable in this embodiment is different, specifically: B1. The raw material of the insulation layer is extruded and coated on the outside of the aluminum alloy conductor to form a polyvinyl chloride insulation layer; B2. 70 parts of composite polyethylene material, 10 parts of polypropylene, 8 parts of ethylene-vinyl acetate copolymer, 20 parts of mullite powder, 2 parts of para-acetaminobenzoic acid, 1.5 parts of antioxidant 168, 1.5 parts of diisodecyl phthalate, and 10 parts of aluminum hydroxide are blended and extruded onto the outside of a polyvinyl chloride insulation layer to obtain a high-temperature resistant flame-retardant cable.

[0034] Comparative Example 1 The only difference between this comparative example and Example 2 is that the preparation method of the composite polyethylene material in this comparative example is different, specifically: A1. Mix 8 parts dolomite powder and 8 parts melamine phosphate evenly, and ball mill at 160 rpm for 30 min to obtain a blend; A2. Blend the blend with 80 parts of polyethylene, extrude, and obtain a composite polyethylene material.

[0035] Comparative Example 2 The only difference between this comparative example and Example 2 is that the preparation method of the composite polyethylene material in this comparative example is different, specifically: A1. Mix 8 parts dolomite powder and 8 parts erythritol evenly, and ball mill at 160 rpm for 30 min to obtain a blend; A2. Blend the blend with 80 parts of polyethylene, extrude, and obtain a composite polyethylene material.

[0036] Comparative Example 3 The only difference between this comparative example and Example 2 is that the preparation method of the composite polyethylene material in this comparative example is different, specifically: A1. Mix 8 parts of melamine phosphate and 8 parts of erythritol evenly, and ball mill at 160 rpm for 30 min to obtain a blend; A2. Blend the blend with 80 parts of polyethylene, extrude, and obtain a composite polyethylene material.

[0037] Comparative Example 4 The only difference between this comparative example and Example 2 is that the preparation method of the composite polyethylene material in this comparative example is different, specifically: A1. Ball mill 8 parts of dolomite powder at 160 rpm for 30 min to obtain the pretreated material; A2. The pretreated material is blended with 80 parts of polyethylene and extruded to obtain a composite polyethylene material.

[0038] Comparative Example 5 The only difference between this comparative example and Example 2 is that, in this comparative example, the composite polyethylene material is replaced with an equal amount of polyethylene.

[0039] Experimental Example 1 Three samples were cut from the sheath of the high-temperature flame-retardant cables prepared in Examples 1-6 and Comparative Examples 1-5 to form Type IV oxygen index samples. The oxygen index was tested according to the method in GB / T 2406.2-2009 "Determination of burning behavior by oxygen index method for plastics - Part 2: Room temperature test". The diffusion ignition method was used in the test. The test result is the average value of the three samples. The test results are shown in Table 1.

[0040] Table 1. Flame retardant performance test results of Examples 1-6 and Comparative Examples 1-5

[0041] Compared with Comparative Examples 1-5, the oxygen index of the sheath layer of the high-temperature flame-retardant cable prepared in Examples 1-6 was improved, indicating that after mixing and treating dolomite powder, melamine phosphate and erythritol, and then blending them with polyethylene to obtain a composite polyethylene material, the flame-retardant performance of the sheath layer of the high-temperature flame-retardant cable can be effectively improved.

[0042] Experiment Example 2 Three samples were cut from the sheath of the high-temperature resistant and flame-retardant cables prepared in Examples 5 and 7-11. The samples were prepared into dumbbell-shaped specimens with a thickness of 2 mm according to the method in GB / T 2951.11-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers - Part 11: General Test Methods for Thickness and Dimensional Measurement and Mechanical Properties Test". The tensile strength was tested and the test results are shown in Table 2.

[0043] Table 2. Test results of tensile strength of sheath layer

[0044] Compared with Examples 5 and 11, the tensile strength of the sheath layer of the high-temperature flame-retardant cable prepared in Examples 7-10 is improved. This indicates that when acetaminobenzoic acid is added to the sheath layer of the high-temperature flame-retardant cable, the mechanical strength of the sheath layer of the high-temperature flame-retardant cable can be improved by first mixing acetaminobenzoic acid and mullite powder, and then mixing the mullite powder mixture with other components in the sheath layer, so that its tensile strength can reach more than 24.0 MPa.

[0045] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature resistant and flame-retardant cable, comprising, from the inside out, a conductor, an insulation layer, and a sheath layer, characterized in that, The raw material of the sheath layer comprises the following components in parts by weight: The composition includes 70 parts of composite polyethylene material, 6-12 parts of polypropylene, 5-10 parts of ethylene-vinyl acetate copolymer, 10-20 parts of mullite powder, 1-2 parts of antioxidant, 1-3 parts of plasticizer, and 8-12 parts of flame retardant. The preparation method of the composite polyethylene material includes the following steps: A1. Mix dolomite powder, melamine phosphate and erythritol evenly, and ball mill to obtain a blend; A2. The blend is blended with polyethylene and extruded to obtain a composite polyethylene material.

2. The high-temperature resistant flame-retardant cable according to claim 1, characterized in that, The weight ratio of melamine phosphate, erythritol and dolomite powder is 1:1:2~5.

3. The high-temperature resistant flame-retardant cable according to claim 1, characterized in that, The weight ratio of the polyethylene to the dolomite powder is 20:2~5.

4. The high-temperature resistant flame-retardant cable according to claim 1, characterized in that, In step A1, the ball milling speed is 100~200 rpm and the ball milling time is 20~40 min.

5. The high-temperature resistant flame-retardant cable according to claim 1, characterized in that, The raw material of the sheath layer also includes acetaminobenzoic acid.

6. A high-temperature resistant flame-retardant cable according to claim 5, characterized in that, The amount of para-acetaminobenzoic acid added is 10% to 20% of the weight of the mullite powder.

7. The high-temperature resistant flame-retardant cable according to claim 1, characterized in that, The antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 330.

8. A high-temperature resistant flame-retardant cable according to claim 1, characterized in that, The plasticizer includes one or more of diisodecyl phthalate, dioctyl adipate, and diisononyl phthalate.

9. A high-temperature resistant flame-retardant cable according to claim 1, characterized in that, The flame retardant includes one or both of magnesium hydroxide and aluminum hydroxide.

10. A high-temperature resistant flame-retardant cable according to claim 1, characterized in that, The conductor is made of either an aluminum alloy or a copper alloy. The insulation layer is a polyvinyl chloride insulation layer.

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