A flexible flame-retardant signal transmission cable for automobiles and a preparation method thereof

Abstract

The present application relates to the field of cable technology, and specifically discloses a flexible flame-retardant signal transmission cable for automobiles and a preparation method thereof, comprising an internal conductive wire, a first flexible layer, and a second flexible layer, wherein the first flexible layer is wrapped and bonded to the internal conductive wire, and the second flexible layer is wrapped and bonded to the first flexible layer; the first flexible layer is prepared from the first flexible layer raw material, and the first flexible layer raw material includes carbon fiber, hydroxyethyl cellulose, polyethylene glycol, soft epoxy resin and water; the second flexible layer is prepared from the second flexible layer raw material, and the second flexible layer raw material includes polyurethane, sodium bicarbonate, antimony trioxide and methanol. The cable prepared by the present application has the advantages of being soft and having good flame retardant properties.

Description

Technical Field

[0001] The present application relates to the field of cable technology, and more specifically, to a flexible flame-retardant signal transmission cable for automobiles and a preparation method thereof. Background Art

[0002] When charging an electric vehicle, it must be connected to the charging pile through a cable, and the cable must withstand a high-power current of 10-20kw. In order to avoid the risk of large-scale electric shock, it must have excellent flame retardant properties. And because the internal conductive wire of the cable that withstands high-power electricity is large in diameter and heavy in weight, the flexibility of the cable becomes an effective way to reduce the effort of users when using the cable, so there is an urgent need for a cable that is both flexible and flame retardant.

[0003] The patent with authorization announcement number CN103589056B provides a cold-resistant flame-retardant cable material for electric vehicles, which is made from the following raw materials: tetraphenylethylene, polypropylene resin, SEBS, halogen-free flame retardant, white oil, and additives. The additives are composed of the following materials: maleic anhydride compatibilizer, hindered phenol antioxidant, cold-resistant plasticizer, kaolin, and stearic acid. The preparation steps are as follows: (1) tetraphenylethylene, polypropylene resin, SEBS, and white oil raw materials are mixed in an extruder according to the above-mentioned proportions, stirred for 5-10 minutes, and then allowed to stand for 50-60 minutes; (2) other raw materials are added according to the above-mentioned proportions, mixed and stirred at high speed for 3-5 minutes; (3) granulated by extrusion by an extruder and air-dried.

[0004] The flame retardant effect of the above cable material is achieved only by adding halogen-free flame retardants, and the cable material air-dried after mixing with other components is not soft enough, and has the disadvantages of poor flame retardant effect and softness. Summary of the invention

[0005] In order to solve the above-mentioned problem of poor softness and flame retardancy of the cable, the present application provides a flexible flame retardant signal transmission cable for automobiles and a preparation method thereof.

[0006] The present application provides a flexible flame-retardant signal transmission cable for automobiles, which adopts the following technical solution:

[0007] A flexible flame-retardant signal transmission cable for automobiles comprises an internal conductive wire, a first flexible layer and a second flexible layer, wherein the first flexible layer is wrapped around and bonded to the internal conductive wire, and the second flexible layer is wrapped around and bonded to the first flexible layer; the first flexible layer is prepared from a first flexible layer raw material, which comprises carbon fiber, hydroxyethyl cellulose, polyethylene glycol, soft epoxy resin and water; the second flexible layer is prepared from a second flexible layer raw material, which comprises polyurethane, sodium bicarbonate, antimony trioxide and methanol.

[0008] By adopting the above technical solution, the carbon fiber in the first flexible layer can not only shield electromagnetic radiation, but also has excellent properties of softness, good toughness, friction resistance and good flame retardancy. The soft epoxy resin is coated on the surface of the carbon fiber, which can make the carbon fiber have insulation properties. Hydroxyethyl cellulose and polyethylene glycol are used to evenly disperse the carbon fiber in water, so that the carbon fiber in the first flexible layer is evenly distributed. The main component of the second flexible layer, polyurethane, is a polymer with good flexibility and friction resistance. Sodium bicarbonate can be decomposed to obtain carbon dioxide. Antimony trioxide itself has flame retardant properties. Sodium bicarbonate wrapped in antimony trioxide can store carbon dioxide in the second flexible layer, enhancing the flame retardant properties and softness of the second flexible layer.

[0009] Optionally, the first flexible layer raw material includes the following components in parts by weight: 20-30 parts of carbon fiber, 1-3 parts of hydroxyethyl cellulose, 2-4 parts of polyethylene glycol, 5-15 parts of soft epoxy resin and 50-70 parts of water.

[0010] By adopting the above technical scheme, the main component carbon fiber ensures the flame retardancy, softness and wear resistance of the first flexible layer. A small amount of soft epoxy resin can wrap the carbon fiber while reducing the weight of the cable, making the carbon fiber insulating. Even smaller amounts of hydroxyethyl cellulose and polyethylene glycol can reduce the weight of the cable while improving the uniformity of the distribution of carbon fiber in the first flexible layer.

[0011] Optionally, the second flexible layer raw material includes the following components in parts by weight: 30-40 parts of polyurethane, 5-10 parts of sodium bicarbonate, 16-19 parts of antimony trioxide and 20-40 parts of methanol.

[0012] By adopting the above technical solution, sodium bicarbonate is insoluble in methanol, so when methanol is used as a solvent, sodium bicarbonate can be dispersed and maintain its original small particle state, and antimony trioxide is also insoluble in methanol, so antimony trioxide will be further adsorbed on the surface of sodium bicarbonate. After the solvent is removed, sodium bicarbonate wrapped in antimony trioxide is formed. The sodium bicarbonate wrapped in antimony trioxide is added to the main component polyurethane. When external heating is applied, the sodium bicarbonate decomposes into carbon dioxide gas, and the carbon dioxide gas and antimony trioxide simultaneously play a flame retardant role; and the gas properties of carbon dioxide further increase the softness of the second flexible layer.

[0013] Optionally, the first flexible layer is provided with one or more layers, and the second flexible layer is provided with one or more layers, and the first flexible layer and the second flexible layer are alternately wrapped and bonded to the internal conductive wire in sequence.

[0014] By adopting the above technical solution, the first flexible layer and the second flexible layer are alternately wrapped and bonded, so that the first flexible layer and the second flexible layer with different functions are integrally formed, thereby reducing the volume of the cable. After the cable is folded multiple times, there will be no misalignment and friction between the first flexible layer and the second flexible layer, thereby reducing the force on the cable when it is folded and extending the service life of the cable.

[0015] Optionally, the length of the carbon fiber is 3-10 mm.

[0016] By adopting the above technical solution, shorter carbon fibers can be more evenly dispersed in the first flexible layer, and arranged in staggered directions in the first flexible layer, so that the tensile force of the carbon fibers in the first flexible layer extends in all directions, thereby enhancing the softness and toughness of the first flexible layer.

[0017] Optionally, the antimony trioxide is coated with sodium bicarbonate.

[0018] By adopting the above technical solution, antimony trioxide is coated with sodium bicarbonate. When the external temperature is high, the sodium bicarbonate decomposes to produce carbon dioxide. The carbon dioxide is a gas, which not only enhances the softness of the second flexible layer, but also plays a flame retardant role together with antimony trioxide.

[0019] Optionally, the particle size of the antimony trioxide is smaller than that of the sodium bicarbonate.

[0020] By adopting the above technical solution, the particle size of antimony trioxide is smaller than that of sodium bicarbonate, which is beneficial to increase the contact area between antimony trioxide and sodium bicarbonate particles on irregular surfaces, so that antimony trioxide can form a sphere around sodium bicarbonate, increase the uniformity of sodium bicarbonate and antimony trioxide in the second flexible layer, ensure that the contact area between antimony trioxide and polyurethane is maximized, and make it difficult for carbon dioxide gas decomposed by sodium bicarbonate to overflow, and evenly store it in the second flexible layer, so as to maximize the flame retardant effect of sodium bicarbonate and antimony trioxide.

[0021] In a second aspect, the present application provides a method for preparing a flexible flame-retardant signal transmission cable for automobiles, which adopts the following technical solution.

[0022] A method for preparing a flexible flame-retardant signal transmission cable for automobiles comprises the following steps: using a multi-layer co-extrusion extruder to simultaneously extrude a first flexible layer raw material and a second flexible layer raw material at 160-180° C. to form an internal conductive wire sequentially coated with the first flexible layer and the second flexible layer, thereby obtaining a flexible flame-retardant signal transmission cable for automobiles.

[0023] By adopting the above technical solution, the first flexible layer and the second flexible layer are extruded simultaneously through a multi-layer co-extrusion extruder. In the final cable, the first flexible layer and the second flexible layer are bonded to each other, the flame retardancy and softness of the cable are integrated, and internal misalignment friction will not occur due to bending of the cable, thereby reducing the stress on the cable when it is used.

[0024] Optionally, the preparation method of the first flexible layer includes the following steps: stirring carbon fiber, hydroxyethyl cellulose, polyethylene glycol and water evenly, then adding soft epoxy resin, stirring evenly, filtering to remove water, and obtaining the first flexible layer raw material.

[0025] By adopting the above technical scheme, hydroxyethyl cellulose and polyethylene glycol are first added to water to make the carbon fiber evenly dispersed in the water; then the soft epoxy resin is added to the water. Since the soft epoxy resin is insoluble in water, the soft epoxy resin will adhere to the surface of the carbon fiber during stirring, and gradually form carbon fiber coated with soft epoxy resin. While ensuring that the carbon fiber plays its own role, the insulation of the carbon fiber is guaranteed to the greatest extent. The first flexible layer finally obtained can better shield electromagnetic radiation, and has good softness, friction resistance, flame retardancy and insulation.

[0026] Optionally, the preparation method of the second flexible layer includes the following steps: mixing sodium bicarbonate and methanol and stirring them evenly, then adding antimony trioxide, mixing and stirring, and removing methanol to obtain fireproof particles; mixing polyurethane and fireproof particles to obtain the raw material of the second flexible layer.

[0027] By adopting the above technical scheme, firstly, sodium bicarbonate is dispersed with methanol. Since sodium bicarbonate is insoluble in methanol, sodium bicarbonate will appear in small particles; then antimony trioxide is added. Antimony trioxide is also insoluble in methanol. Therefore, under stirring, antimony trioxide will gradually adsorb on the surface of sodium bicarbonate to form fireproof particles; finally, polyurethane is mixed with the fireproof particles, so that the fireproof particles are evenly distributed in the polyurethane, and the polyurethane can fill the remaining gaps between the antimony trioxide particles, so that the carbon dioxide gas decomposed by sodium bicarbonate is not easy to overflow and can be stored in the second flexible layer, thereby increasing the softness of the second flexible layer and enhancing the flame retardant effect of the second flexible layer.

[0028] In summary, this application has the following beneficial effects:

[0029] 1. In the first flexible layer of the present application, the soft epoxy resin is coated on the surface of the carbon fiber, which can make the carbon fiber have insulating properties and make the carbon fiber evenly distributed in the first flexible layer; the main component of the second flexible layer, polyurethane, is a polymer with good flexibility and friction resistance, sodium bicarbonate can be decomposed to obtain carbon dioxide gas, antimony trioxide itself has flame retardant properties, and sodium bicarbonate wrapped in antimony trioxide can store carbon dioxide gas in the second flexible layer, thereby enhancing the flame retardant properties and softness of the second flexible layer.

[0030] 2. In the present application, the contact area between antimony trioxide and the irregular surface of sodium bicarbonate particles is large, and antimony trioxide can form a sphere around sodium bicarbonate, increasing the uniformity of sodium bicarbonate and antimony trioxide in the second flexible layer, maximizing the contact area between antimony trioxide and polyurethane, and the carbon dioxide gas decomposed by sodium bicarbonate is difficult to overflow and is evenly stored in the second flexible layer, which can maximize the flame retardant effect of sodium bicarbonate and antimony trioxide.

[0031] 3. In the present application, the first flexible layer and the second flexible layer are extruded simultaneously through a multi-layer co-extrusion extruder, and the first flexible layer and the second flexible layer are bonded to each other, so that the flame retardancy and softness of the cable are integrated; therefore, the prepared cable will not have internal misalignment and friction due to bending, and when the user pulls the cable, the force on the cable can be reduced, thereby extending the service life of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic cross-sectional view of the flexible flame-retardant signal transmission cable for automobiles prepared in Example 8.

[0033] Figure numerals: 1. internal conductive line; 2. first flexible layer; 3. second flexible layer. DETAILED DESCRIPTION

[0034] The raw materials of the examples and comparative examples of the present application can all be purchased commercially.

[0035] Carbon fiber, model: DER732; soft epoxy resin, model: ZK2812; sodium bicarbonate, purity, 99%; antimony trioxide, purity, 99.5%; hydroxyethyl cellulose, product number: 8.22063; polyethylene glycol, product number: 8.07491; methanol, analytical grade.

[0036] The present application is further described in detail below in conjunction with embodiments and comparative examples.

[0037] Example 1

[0038] A method for preparing a flexible flame-retardant signal transmission cable for automobiles comprises the following steps:

[0039] Step 1, preparing the first flexible layer raw material: 20g of carbon fiber with a length of 3-10mm, 3g of hydroxyethyl cellulose, 2g of polyethylene glycol and 50g of water are stirred at 60°C at a speed of 300rpm for 30min, and then 15g of soft epoxy resin is added dropwise at a speed of 1μL / s. After the addition is completed, stirring is continued at 40°C at a speed of 500rpm for 24h, and a filter with a pore size of 0.1mm is used to filter and remove water to obtain the first flexible layer raw material;

[0040] Step 2, prepare the second flexible layer raw material: mix 10g of sodium bicarbonate with a particle size of 10-20 mesh with 40g of methanol, stir at 500rpm at 4°C for 1h, then add 16g of antimony trioxide with a particle size of 20-30nm, stir at 500rpm at 4°C for 2.5h to obtain a fire-retardant particle precursor solution; centrifuge the fire-retardant particle precursor solution at 1000rpm at 4°C to remove methanol to obtain fire-retardant particles; stir 30g of polyurethane and fire-retardant particles at 30rpm at room temperature for 2h to obtain the second flexible layer raw material.

[0041] Step 3, using a multi-layer co-extrusion extruder, and referring to the QC / T1037-2016 standard, the first flexible layer raw material and the second flexible layer raw material are extruded simultaneously at 165°C, and then immediately cooled by water to form an internal conductive wire 1 covered with the first flexible layer 2 and the second flexible layer 3 in sequence, to obtain a flexible flame-retardant signal transmission cable for automobiles.

[0042] Example 2

[0043] A method for preparing a flexible flame-retardant signal transmission cable for automobiles comprises the following steps:

[0044] Step 1, preparing the first flexible layer raw material: 30g of carbon fiber with a length of 3-10mm, 1g of hydroxyethyl cellulose, 4g of polyethylene glycol and 70g of water are stirred at 300rpm for 30min at 60°C, and then 5g of soft epoxy resin is added dropwise at a speed of 1μL / s. After the addition is completed, stirring is continued at 40°C at a speed of 500rpm for 24h, and a filter with a pore size of 0.1mm is used to filter and remove water to obtain the first flexible layer raw material;

[0045] Step 2, prepare the second flexible layer raw material: mix 8g of sodium bicarbonate with a particle size of 10-20 mesh with 30g of methanol, stir at 500rpm at 4°C for 1h, then add 17g of antimony trioxide with a particle size of 20-30nm, stir at 500rpm at 4°C for 2.5h to obtain a fire-retardant particle precursor solution; centrifuge the fire-retardant particle precursor solution at 1000rpm at 4°C to remove methanol to obtain fire-retardant particles; stir 35g of polyurethane and fire-retardant particles at 30rpm at room temperature for 2h to obtain the second flexible layer raw material.

[0046] Step 3, using a multi-layer co-extrusion extruder, and referring to the QC / T1037-2016 standard, the first flexible layer raw material and the second flexible layer raw material are extruded simultaneously at 165°C, and then immediately cooled by water to form an internal conductive wire 1 covered with the first flexible layer 2 and the second flexible layer 3 in sequence, to obtain a flexible flame-retardant signal transmission cable for automobiles.

[0047] Example 3

[0048] A method for preparing a flexible flame-retardant signal transmission cable for automobiles comprises the following steps:

[0049] Step 1, preparing the first flexible layer raw material: 25g of carbon fiber with a length of 3-10mm, 2g of hydroxyethyl cellulose, 3g of polyethylene glycol and 60g of water are stirred at 300rpm for 30min at 60°C, and then 10g of soft epoxy resin is added dropwise at a speed of 1μL / s. After the addition is completed, stirring is continued at 40°C at a speed of 500rpm for 24h, and a filter with a pore size of 0.1mm is used to filter and remove water to obtain the first flexible layer raw material;

[0050] Step 2, prepare the second flexible layer raw material: mix 10g of sodium bicarbonate with a particle size of 10-20 mesh with 40g of methanol, stir at 500rpm at 4°C for 1h, then add 16g of antimony trioxide with a particle size of 20-30nm, stir at 500rpm at 4°C for 2.5h to obtain a fire-retardant particle precursor liquid; centrifuge the fire-retardant particle precursor liquid at 1000rpm at 4°C to remove methanol to obtain fire-retardant particles; stir 30g of polyurethane and fire-retardant particles at 30rpm at room temperature for 2h to obtain the second flexible layer raw material.

[0051] Step 3, using a multi-layer co-extrusion extruder, and referring to the QC / T1037-2016 standard, the first flexible layer raw material and the second flexible layer raw material are extruded simultaneously at 165°C, and then immediately cooled by water to form an internal conductive wire 1 covered with the first flexible layer 2 and the second flexible layer 3 in sequence, to obtain a flexible flame-retardant signal transmission cable for automobiles.

[0052] Example 4

[0053] The difference from Example 3 is that the length of the carbon fiber in step 1 is 3-10 cm.

[0054] Example 5

[0055] The difference from Example 3 is that the antimony trioxide in step 2 is replaced by chlorinated paraffin of equal weight and equal particle size.

[0056] Example 6

[0057] The difference from Example 5 is that the soft epoxy resin is not added dropwise in step 1. The specific steps of step 1 are as follows:

[0058] Step 1, prepare the first flexible layer raw material: stir 25g carbon fiber, 2g hydroxyethyl cellulose, 3g polyethylene glycol and 60g water at 60°C at 300rpm for 30min, then directly add 10g soft epoxy resin. After the addition is completed, continue stirring at 40°C at 500rpm for 24h, filter with a filter with a pore size of 0.1mm to remove water, and obtain the first flexible layer raw material.

[0059] Example 7

[0060] The difference from Example 3 is that the order of adding raw materials in step 1 and step 2 is different; the specific steps are as follows:

[0061] A method for preparing a flexible flame-retardant signal transmission cable for automobiles comprises the following steps:

[0062] Step 1, preparing the first flexible layer raw material: 25g carbon fiber, 2g hydroxyethyl cellulose, 3g polyethylene glycol, 10g soft epoxy resin and 60g water are stirred at 60°C at a speed of 300rpm for 30min, and then stirred at 40°C at a speed of 500rpm for 24h, and filtered through a filter with a pore size of 0.1mm to remove water, to obtain the first flexible layer raw material;

[0063] Step 2, prepare the raw material for the second flexible layer: mix 10g of sodium bicarbonate with a particle size of 10-20 mesh, 16g of antimony trioxide with a particle size of 20-30nm and 40g of methanol, and stir at 500rpm for 3.5h at a temperature of 4°C to obtain a fire-retardant particle precursor liquid; centrifuge the fire-retardant particle precursor liquid at a speed of 1000rpm at a temperature of 4°C to remove methanol to obtain fire-retardant particles; stir 30g of polyurethane and fire-retardant particles at a speed of 30rpm at room temperature for 2h to obtain the raw material for the second flexible layer.

[0064] Step 3, using a multi-layer co-extrusion extruder, and referring to the QC / T1037-2016 standard, the first flexible layer raw material and the second flexible layer raw material are extruded simultaneously at 165°C, and then immediately cooled by water to form an internal conductive wire 1 covered with the first flexible layer 2 and the second flexible layer 3 in sequence, to obtain a flexible flame-retardant signal transmission cable for automobiles.

[0065] Example 8

[0066] The difference from Example 3 is that the extrusion method in step 3 is different, that is, four-layer extrusion, the first flexible layer 2 and the second flexible layer 3 are two layers each, and the wrapping layers from the inner conductive wire 1 to the outer layer are the first flexible layer 2, the second flexible layer 3, the first flexible layer 2 and the second flexible layer 3 in sequence; the specific steps of step 3 are as follows:

[0067] Step 3, using a multi-layer co-extruder, and referring to the QC / T1037-2016 standard, two layers of the first flexible layer raw material and two layers of the second flexible layer raw material are extruded at 165°C, and then immediately cooled by water to form an inner conductive wire 1 (such as Figure 1 As shown), a flexible flame-retardant signal transmission cable for automobiles is obtained.

[0068] Example 9

[0069] The difference from Example 3 is that the extrusion method in step 3 is different, that is, six-layer extrusion, the first flexible layer 2 and the second flexible layer 3 each have three layers, and the wrapping layers from the inner conductive wire 1 to the outer layer are the first flexible layer 2, the second flexible layer 3, the first flexible layer 2, the second flexible layer 3, the first flexible layer 2 and the second flexible layer 3; the specific steps of step 3 are as follows:

[0070] Step 3, using a multi-layer co-extrusion extruder, and referring to the QC / T1037-2016 standard, three layers of the first flexible layer raw material and three layers of the second flexible layer raw material are extruded simultaneously at 165°C, and then immediately cooled by water to form an internal conductive wire 1 which is sequentially coated with the first flexible layer 2, the second flexible layer 3, the first flexible layer 2, the second flexible layer 3, the first flexible layer 2 and the second flexible layer 3, to obtain a flexible flame-retardant signal transmission cable for automobiles.

[0071] Comparative Example 1

[0072] The difference from Example 3 is that no soft epoxy resin is added in step 1.

[0073] Comparative Example 2

[0074] The difference from Example 3 is that sodium bicarbonate is not added in step 2.

[0075] Comparative Example 3

[0076] The difference from Example 3 is that antimony trioxide is not added in step 2.

[0077] Comparative Example 4

[0078] The difference from Example 3 is that the raw materials of step 1 and step 2 are mixed together; the specific steps are as follows:

[0079] A method for preparing a flexible flame-retardant signal transmission cable for automobiles comprises the following steps:

[0080] Step 1, preparing a transmission cable layer raw material: 25g of carbon fiber, 2g of hydroxyethyl cellulose, 3g of polyethylene glycol, 10g of soft epoxy resin, 60g of water, 10g of sodium bicarbonate with a particle size of 10-20 mesh, 40g of methanol and 16g of antimony trioxide with a particle size of 20-30nm are stirred at 4°C at a speed of 500rpm for 30h, and filtered through a filter with a pore size of 0.1mm to remove water and methanol to obtain a signal transmission cable layer raw material;

[0081] Step 2, using a single-layer co-extrusion extruder, and referring to the QC / T1037-2016 standard, the signal cable layer raw material is extruded at 165° C., and then immediately cooled by water to form an internal conductive wire 1 coated with a transmission cable layer, thereby obtaining a flexible flame-retardant signal transmission cable for automobiles.

[0082] Comparative Example 5

[0083] The difference from Example 3 is that the extrusion temperature in step 3 is different; the specific steps are as follows:

[0084] Step 3, using a multi-layer co-extrusion extruder, and referring to the QC / T1037-2016 standard, the first flexible layer raw material and the second flexible layer raw material are extruded simultaneously at 250°C, and then immediately cooled by water to form an internal conductive wire 1 covered with the first flexible layer 2 and the second flexible layer 3 in sequence, to obtain a flexible flame-retardant signal transmission cable for automobiles.

[0085] Comparative Example 6

[0086] The difference from Example 3 is that the extrusion temperature in step 3 is different; the specific steps are as follows:

[0087] Step 3, using a multi-layer co-extrusion extruder, and referring to the QC / T1037-2016 standard, the first flexible layer raw material and the second flexible layer raw material are extruded simultaneously at 150°C, and then immediately cooled by water to form an internal conductive wire 1 covered with the first flexible layer 2 and the second flexible layer 3 in sequence, to obtain a flexible flame-retardant signal transmission cable for automobiles.

[0088] Performance testing:

[0089] Detection method:

[0090] The cable ends prepared in the present application are cut off as the standard cable products of the present application. The cable ends are used for performance parameter testing, so there are no internal conductive wires.

[0091] Low temperature winding test: According to the specification CQC1105-2015 "Technical Specifications for Cables for Electric Vehicle Conductive Charging Systems Part 3: Cables for DC Charging Systems", a low temperature winding test at -40°C is conducted to observe whether the cable has cracks;

[0092] Low temperature tensile test: According to the specification CQC1105-2015 "Technical Specifications for Cables for Electric Vehicle Conductive Charging Systems Part 3: Cables for DC Charging Systems", a low temperature tensile test at -40°C was conducted to test the elongation at break;

[0093] Oxygen index test: The so-called oxygen index (OI) refers to the minimum oxygen concentration required to maintain the combustion of the sample, according to the specification (GB2466-80);

[0094] Oxygen index (OI) = oxygen flow (L / min) / (oxygen flow (L / min) + nitrogen flow (L / min))

[0095] ×100%; the larger the OI, the better the flame retardancy;

[0096] The test results are in Table 1 below:

[0097] Table 1 Cable flexibility and flame retardancy test table

[0098]

[0099] Combining the data of Examples 1, 2, and 3, it can be seen that the only difference between Examples 1, 2, and 3 is the different raw material composition ratios. The standard sample of Example 3 has a higher elongation at break and an oxygen index than the standard samples of Examples 1 and 2. Therefore, the raw material ratio of Example 3 is the optimal ratio for preparing the standard sample of the cable of this application.

[0100] The difference between Example 4 and Example 3 is that the length of the chopped carbon fiber in Example 4 is 3-10 cm, while the length of the chopped carbon fiber in Example 3 is 3-10 mm. It can be seen from the data in Table 1 that the elongation at break of the standard cable sample prepared in Example 4 is lower than that of the standard cable sample prepared in Example 3, and the oxygen index of the standard cable sample prepared in Example 4 is lower than that of the standard cable sample prepared in Example 3; this proves that the chopped carbon fiber in the present application cannot be replaced by a longer carbon fiber.

[0101] The difference between Example 5 and Example 3 is that the fireproof material of Example 5 is chlorinated paraffin, while the fireproof material of Example 3 is antimony trioxide. It can be seen from the data in Table 1 that the elongation at break of the standard cable sample prepared in Example 5 is lower than that of the standard cable sample prepared in Example 3, and the oxygen index of the standard cable sample prepared in Example 5 is lower than that of the standard cable sample prepared in Example 3; this proves that the antimony trioxide in this application cannot be replaced by other fireproof materials.

[0102] The difference between Example 6 and Example 3 is that the soft epoxy resin in Example 6 is added directly in its entirety, while the soft epoxy resin in Example 3 is added dropwise; it can be seen from the data in Table 1 that the elongation at break of the standard cable sample prepared in Example 6 is lower than that of the standard cable sample prepared in Example 3, and the oxygen index of the standard cable sample prepared in Example 6 is lower than that of the standard cable sample prepared in Example 3; this proves that, in the step of preparing the standard cable sample in the present application, the change in the addition method of the soft epoxy resin will affect the performance of the prepared standard cable sample.

[0103] The difference between Example 7 and Example 5 is that, compared with the preparation steps of Example 5, Example 7 does not carry out step by step in step 1 and step 2; it can be seen from the data in Table 1 that the elongation at break of the standard cable sample prepared in Example 7 is lower than the elongation at break of the standard cable sample prepared in Example 3, and the oxygen index of the standard cable sample prepared in Example 7 is lower than the oxygen index of the standard cable sample prepared in Example 3; it is proved that the preparation steps of the present application cannot be changed at will, and changing the preparation steps will affect the structure of the final prepared standard cable sample, thereby reducing the performance of the standard cable sample.

[0104] Compared with Example 3, in Step 3, Examples 8 and 9 have four, six and three extruded layers, respectively. It can be seen from the data in Table 1 that the elongation at break of the standard cable samples prepared in Examples 9 and 3 is lower than the elongation at break of the standard cable sample prepared in Example 8, and the oxygen index of the standard cable samples prepared in Examples 9 and 3 is lower than the oxygen index of the standard cable sample prepared in Example 8. This proves that the more layers the cable in this application has, the better, and the optimal number of layers is 4.

[0105] Compared with Example 3, Comparative Example 1 does not add soft epoxy resin, and the microstructure of the standard cable sample prepared in Comparative Example 1 is different from the microstructure of the standard sample prepared in Example 3; it can be seen from the data in Table 1 that the elongation at break of the standard cable sample prepared in Comparative Example 1 is lower than the elongation at break of the standard cable sample prepared in Example 3, and the oxygen index of the standard cable sample prepared in Comparative Example 1 is lower than the oxygen index of the standard cable sample prepared in Example 3, and there are slight cracks on the surface at low temperature; it is proved that the addition of soft epoxy resin in this application is indispensable.

[0106] Compared with Example 3, Comparative Examples 2 and 3 do not add sodium bicarbonate and antimony trioxide respectively; it can be seen from the data in Table 1 that the elongation at break of the standard cable samples prepared in Comparative Examples 2 and 3 is lower than the elongation at break of the standard cable samples prepared in Example 3, and the oxygen index of the standard cable samples prepared in Comparative Examples 2 and 3 is much lower than the oxygen index of the standard cable samples prepared in Example 3; it is proved that sodium bicarbonate and antimony trioxide in the present application are very important for the flame retardant properties of the standard cable samples, and the preparation of the standard cable samples is essential.

[0107] Compared with Example 3, Comparative Example 4 does not distinguish between the first flexible layer and the second flexible layer, but mixes all the raw materials to prepare the signal transmission cable layer raw material, and directly extrude a single layer of the raw material to cover the internal conductive wire; it can be seen from the data in Table 1 that the elongation at break of the standard cable sample prepared in Comparative Example 4 is lower than the elongation at break of the standard cable sample prepared in Example 3, and the oxygen index of the standard cable sample prepared in Comparative Example 4 is lower than the oxygen index of the standard cable sample prepared in Example 3, and there are more cracks on the bending surface at low temperature; it proves that the preparation steps and the number of extrusion layers of this application are very important.

[0108] Compared with Example 3, in step 3, the extrusion temperatures of Comparative Examples 5 and 6 are 250°C, 150°C, and 165°C, respectively; it can be seen from the data in Table 1 that the elongation at break of the standard cable samples prepared in Comparative Examples 5 and 6 is lower than that of the standard cable samples prepared in Example 3, and the oxygen index of the standard cable samples prepared in Comparative Examples 5 and 6 is lower than that of the standard cable samples prepared in Example 3; it is proved that the extrusion temperature of the preparation step of the present application will affect the structure of the standard cable material, thereby affecting the performance of the standard cable sample material, and therefore, the extrusion temperature of the present application cannot be changed over a large range.

[0109] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A flexible flame-retardant signal transmission cable for automobiles, characterized in that: The invention comprises an internal conductive wire (1), one or more first flexible layers (2), and one or more second flexible layers (3), wherein the first flexible layer (2) is wrapped on the internal conductive wire (1), the second flexible layer (3) is wrapped on the first flexible layer (2) and bonded, and other first flexible layers (2) and second flexible layers (3) are alternately wrapped and bonded; the first flexible layer (2) is prepared from a first flexible layer raw material, which comprises carbon fiber, hydroxyethyl cellulose, polyethylene glycol, soft epoxy resin, and water; the second flexible layer (3) is prepared from a second flexible layer raw material, which comprises polyurethane, sodium bicarbonate, antimony trioxide, and methanol; The length of the carbon fiber is 3-10 mm; The antimony trioxide is coated with sodium bicarbonate; The first flexible layer raw material includes the following materials in parts by weight: 20-30 parts of carbon fiber, 1-3 parts of hydroxyethyl cellulose, 2-4 parts of polyethylene glycol, 5-15 parts of soft epoxy resin and 50-70 parts of water; The second flexible layer raw material includes the following substances in parts by weight: 30-40 parts of polyurethane, 5-10 parts of sodium bicarbonate, 16-19 parts of antimony trioxide and 20-40 parts of methanol.

2. The flexible flame-retardant signal transmission cable for automobiles according to claim 1, characterized in that: The particle size of the antimony trioxide is smaller than that of the sodium bicarbonate.

3. A method for preparing a flexible flame-retardant signal transmission cable for automobiles as claimed in any one of claims 1 to 2, characterized in that: The following steps are involved: A multi-layer co-extrusion extruder is used to extrude the first flexible layer raw material and the second flexible layer raw material simultaneously at 160-180° C. to form an internal conductive wire (1) covered with the first flexible layer (2) and the second flexible layer (3) in sequence, thereby obtaining a flexible flame-retardant signal transmission cable for automobiles.

4. The method for preparing a flexible flame-retardant signal transmission cable for automobiles according to claim 3, characterized in that: The preparation method of the first flexible layer raw material comprises the following steps: carbon fiber, hydroxyethyl cellulose, polyethylene glycol and water are stirred evenly, then soft epoxy resin is added, stirred evenly, filtered to remove water, and the first flexible layer raw material is obtained.

5. The method for preparing a flexible flame-retardant signal transmission cable for automobiles according to claim 3, characterized in that: The preparation method of the second flexible layer raw material includes the following steps: mixing sodium bicarbonate and methanol evenly, then adding antimony trioxide, mixing and stirring, and removing methanol to obtain fireproof particles; mixing polyurethane and fireproof particles to obtain the second flexible layer raw material.

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