EPDM (ethylene-propylene-diene monomer) flame-retardant water pipe material for charging pile as well as preparation method and application thereof

Abstract

The invention relates to the technical field of flame-retardant water pipe materials, and particularly discloses an EPDM flame-retardant water pipe material for a charging pile and a preparation method and application of the EPDM flame-retardant water pipe material. The invention discloses an EPDM flame-retardant water pipe material for a charging pile. The EPDM flame-retardant water pipe material comprises the following components: 100 parts of EPDM raw rubber, 40-70 parts of fast extruding furnace black N550, 90-140 parts of a flame retardant, 3-5 parts of a silane coupling agent A-172, 20-40 parts of paraffin oil, 4-8 parts of magnesium oxide, 0.5-1.5 parts of stearic acid, 7-10 parts of peroxide and 1-3 parts of an assistant crosslinking agent. The flame retardant is formed by compounding a phosphorus-nitrogen flame retardant and aluminum hydroxide. The flame-retardant water pipe material provided by the invention is prepared by optimizing a formula, and has excellent performance of wide temperature range stability, mechanical-flame-retardant synergy, sealing and damage resistance.

Description

Technical Field

[0001] This application relates to the technical field of flame-retardant water pipe materials, specifically to an EPDM flame-retardant water pipe material for charging piles, its preparation method, and its application. Background Technology

[0002] As a critical component of the liquid cooling system, cooling water pipes must possess flame-retardant properties (for example, during high-power fast charging, if the cooling water pipes are flammable, they may exacerbate the fire in the event of high temperatures or circuit failures, threatening equipment and personnel safety). While ensuring flame retardancy, cooling water pipes also need to maintain good resilience and strength, without affecting their pressure-bearing, bending / sealing performance within the liquid cooling system. This ensures the stable operation of the cooling circulation system and prevents ruptures or leaks due to deterioration in the pipes' mechanical properties.

[0003] During fast charging, the coolant circulates inside the liquid cooling system, and the pipes come into contact with high temperatures of 50~80℃. In cold regions or winter, the ambient temperature may drop to -30℃ or even lower. The pipes need to maintain stable performance over a wide temperature range and cannot become brittle or softened due to alternating hot and cold temperatures.

[0004] Existing materials cannot simultaneously meet the requirements of multiple performance indicators such as flame retardancy, resilience, and strength, as well as stability under a wide temperature range. Therefore, it is of great significance to develop flame-retardant water pipe materials with excellent comprehensive performance. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides an EPDM flame-retardant water pipe material for charging piles, its preparation method, and its application.

[0006] In the first aspect, this application provides an EPDM flame-retardant water pipe material for charging piles, specifically comprising the following components in parts by weight: 80-120 parts EPDM raw rubber, 40-70 parts fast-extrusion carbon black N550, 90-140 parts flame retardant, 3-5 parts silane coupling agent A-172, 20-40 parts paraffin oil, 4-8 parts magnesium oxide, 0.5-1.5 parts stearic acid, 7-10 parts peroxide, and 1-3 parts crosslinking agent; The flame retardant is composed of phosphorus-nitrogen flame retardants and aluminum hydroxide in a weight ratio of 4~6:5~8.

[0007] The design principle of the technical solution provided in this application is as follows: When meeting the wide-temperature-range requirements of liquid-cooled pipelines in charging piles, optimizing the low-temperature performance of EPDM is crucial due to its good high-temperature resistance and aging resistance, especially its stable performance below 100℃. By using EPDM grades with low ethylene content, the material's flexibility and resistance to embrittlement in low-temperature environments can be effectively improved by utilizing its molecular chain structure characteristics. Specifically, the low ethylene content increases the proportion of propylene units in the EPDM molecular chain, reducing the tendency and crystallinity of the molecular chain, and minimizing the ordered arrangement and hardening of the molecular chain at low temperatures. Simultaneously, the lower ethylene content helps weaken the cohesive forces between molecular chains, allowing them to maintain a relatively free movement at low temperatures. This significantly improves the material's glass transition temperature (Tg) and low-temperature elasticity, ensuring that the liquid-cooled pipelines maintain good flexibility and impact resistance in extreme low-temperature environments of -40℃ and below, avoiding the risk of pipeline rupture due to low-temperature embrittlement, and guaranteeing stable coolant delivery.

[0008] Fast-extrusion carbon black N550 was selected as the key reinforcing agent to ensure mechanical properties and extrusion molding. Fast-extrusion carbon black N550 possesses moderate structure and suitable particle size, and its unique aggregate morphology can form a uniformly dispersed three-dimensional network structure within the EPDM rubber matrix. During the mixing process, the abundant active sites on the carbon black surface generate strong physical adsorption with the rubber molecular chains, constructing a "filler-rubber" reinforcing network. This significantly improves the tensile strength, tear strength, and fatigue resistance of the material, effectively resisting the external impact of bending and extrusion conditions on the charging pile liquid cooling pipeline. Simultaneously, the structural characteristics of fast-extrusion carbon black N550 endow it with good processing fluidity. During extrusion molding, its moderate structure provides effective reinforcement while avoiding the viscosity surge caused by high-structure carbon black, ensuring stable delivery and uniform plasticization of the rubber compound within the screw extruder, guaranteeing product dimensional accuracy and surface finish. This reinforcing system improves the material's mechanical properties while maintaining excellent extrusion process adaptability, meeting the dual requirements of high-efficiency production and demanding use of charging pile liquid cooling pipelines.

[0009] A flame-retardant system combining phosphorus-nitrogen flame retardants and aluminum hydroxide is employed. When heated, the phosphorus-nitrogen flame retardants release inert gases to dilute flammable gases and promote char formation. Meanwhile, aluminum hydroxide decomposes and absorbs heat upon heating, releasing water vapor to cool the area and improve the density of the char layer. This combination creates a synergistic mechanism of "gas-phase flame retardancy + condensed-phase flame retardancy + cooling and heat absorption," ensuring excellent flame retardancy.

[0010] In the construction of flame-retardant systems, flame retardants, due to their strong surface polarity, have poor compatibility with non-polar rubber matrices and are prone to agglomeration, leading to a decrease in material strength. This solution introduces silane coupling agent surface modification technology to achieve a synergistic improvement in flame retardancy and mechanical properties through molecular-level interface optimization. The alkoxy end of the coupling agent molecule undergoes a dehydration condensation reaction with the hydroxyl group on the flame retardant surface, forming a stable covalent bond; the organic functional group (such as epoxy group) at the other end forms physical entanglement or chemical bonding with the EPDM molecular chain. This modification process constructs a high-strength interfacial transition layer between the flame retardant and the rubber matrix, significantly improving the stress transfer efficiency between the two phases, inhibiting the formation of flame retardant agglomerates, and ensuring that the flame retardant is uniformly dispersed in the rubber network.

[0011] Preferably, the EPDM flame-retardant water pipe material for the charging pile specifically comprises the following components in parts by weight: 90-110 parts EPDM raw rubber, 50-60 parts fast-extruded carbon black N550, 100-130 parts flame retardant, 3.5-4.5 parts silane coupling agent A-172, 25-35 parts paraffin oil, 5-7 parts magnesium oxide, 0.7-1.2 parts stearic acid, 8-9 parts peroxide, and 1.5-2.5 parts crosslinking agent.

[0012] Preferably, the EPDM raw rubber is composed of a mixture of EPDM 8550C and EPDM 2650C in a weight ratio of 1~1.5:1~1.5.

[0013] In one specific implementation, the weight ratio of EPDM 8550C and EPDM 2650C in the EPDM raw rubber can be 1:1, 1:1.2, 1:1.3, 1:1.5, 1.2:1, 1.2:1.3, 1.2:1.5, 1.3:1, 1.3:1.2, 1.3:1.5, 1.5:1, 1.5:1.2, or 1.5:1.3.

[0014] Experimental analysis shows that using EPDM 8550C and EPDM 2650C in the above weight ratio as EPDM raw rubber in this application can further improve the performance of the material.

[0015] Preferably, the flame retardant is composed of a phosphorus-nitrogen flame retardant and aluminum hydroxide in a weight ratio of 4.5~5.5:6~7.

[0016] In one specific implementation, the weight ratio of the phosphorus-nitrogen flame retardant to aluminum hydroxide is 4.5:6, 4.5:7, 5:6, or 5:7. Experimental analysis shows that using phosphorus-nitrogen flame retardants and aluminum hydroxide in the above-mentioned weight ratio as flame retardants can further improve the performance of the material.

[0017] Preferably, the phosphorus-nitrogen flame retardant is nitrogen-phosphorus agent YL-101.

[0018] Preferably, the peroxide is BIPB-40; and the crosslinking agent is TMPTMA.

[0019] Secondly, this application provides a method for preparing the EPDM flame-retardant water pipe material for charging piles, specifically including the following steps in sequence: (1) Mix all the flame retardant, all the paraffin oil, and one-quarter to three-quarters of the amount of silane coupling agent A-172 evenly to form a preliminary mixed slurry; then perform homogenization treatment to obtain a flame retardant pre-dispersion. (2) Add EPDM raw rubber, magnesium oxide and stearic acid to the internal mixer according to the formula ratio, control the temperature at 60~80℃, and after mixing for 20~40s, raise the top plug; (3) Add fast-pressed carbon black N550, flame retardant pre-dispersion and the balance of silane coupling agent to the internal mixer, mix to 100~110℃, raise the top plug 1~2 times in the middle to fully mix the materials evenly. (4) Add peroxide and crosslinking agent to the internal mixer, mix to 115~120℃, and discharge the material; (5) Cool the mixture in a thin pass on the open mill, and then send it to the filter for filtration; (6) Cool the rubber compound to 15~25℃ and then package it.

[0020] Preferably, the process parameters of step (1) are as follows: all the flame retardant, all the paraffin oil, and one-half to two-thirds of the silane coupling agent A-172 are added to a stirring tank at a temperature of 30~40℃ and a rotation speed of 50~100r / min, and stirred and mixed evenly to form a preliminary mixed slurry; then the mixture is transferred to a homogenizer for homogenization to obtain a flame retardant pre-dispersion.

[0021] Preferably, the homogenization process parameters are as follows: first, homogenize for 5 to 20 minutes at a temperature of 30 to 40°C and a working pressure of 30 to 50 MPa; then, homogenize for 20 to 50 minutes at a temperature of 50 to 60°C and a working pressure of 80 to 100 MPa.

[0022] During the experiment, the applicant discovered that by first mixing and homogenizing all the flame retardant, all the paraffin oil, and one-half to two-thirds of the silane coupling agent A-172, and through the impregnation and coupling coating of paraffin oil and silane coupling agent A-172, combined with the homogenization effect of high-speed shearing, the flame retardant is pre-modified by the surface of the silane coupling agent and fully impregnated by the paraffin oil. When this pre-dispersion is added to rubber, it can quickly and uniformly mix with the rubber molecular chains, thereby constructing a high-strength interfacial transition layer, significantly improving the stress transfer efficiency between the two phases, inhibiting the formation of flame retardant agglomerates, and ensuring that the flame retardant is uniformly dispersed in the rubber network. Through the above technical solution, this application can achieve excellent dispersion and good interfacial bonding of the flame retardant in the raw material reaction system, thereby endowing the material product with good mechanical properties and flame retardant properties.

[0023] During the homogenization process, appropriately increasing the temperature can reduce the viscosity of paraffin oil, which helps the material flow and particle breakage; however, the temperature should not be too high, otherwise it may affect the stability of the coupling agent or cause the paraffin oil to volatilize.

[0024] Thirdly, this application provides the application of the aforementioned EPDM flame-retardant water pipe material for charging piles in flame-retardant materials.

[0025] In summary, the technical solution of this application has the following effects: The flame-retardant water pipe material provided in this application has excellent comprehensive performance through optimized formula composition, breaking through the three major industry bottlenecks of "wide temperature range stability, mechanical-flame retardant synergy, and sealing and damage resistance", providing a high-performance and high-reliability solution for liquid cooling heat dissipation systems. Specifically: (1) Wide temperature range stability: This material maintains good resilience in the range of -40~80℃, avoiding hardening and cracking or softening deformation caused by alternating hot and cold temperatures, and ensuring stable transmission of coolant. (2) Guaranteed strength: It can meet the tensile strength ≥10MPa and can be used under complex working conditions. (3) High efficiency flame retardant performance: It adopts a compound system of phosphorus and nitrogen flame retardants and aluminum hydroxide, combined with silane coupling agent interface modification technology, to meet the UL94 V-0 flame retardant requirements under the premise of ensuring performance, significantly reducing the fire risk of charging pile liquid cooling system. (4) Excellent anti-aging performance: After the aging test conditions of 80℃×100h, this material maintains good tensile strength, low temperature resilience and flame retardant performance. Detailed Implementation

[0026] The present application will be further described in detail below with reference to embodiments, comparative examples and performance test results. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0027] Example

[0028] Examples 1-3 Examples 1-3 respectively provide an EPDM flame-retardant water pipe material for charging piles and its preparation method.

[0029] The preparation method of EPDM flame-retardant water pipe material for charging piles in the above embodiments is as follows: (1) All the flame retardant (composed of nitrogen-phosphorus agent YL-101 and aluminum hydroxide in a weight ratio of 4.5:7), all the paraffin oil (P-2286T; provided by Hebei Aidi'er Composite Materials Co., Ltd.), and two-thirds of the silane coupling agent A-172 were added to a stirred tank at a temperature of 35℃ and a speed of 80r / min. The mixture was stirred for 15min and mixed evenly to form a preliminary slurry. Then, it was transferred to a homogenizer for homogenization to obtain a pre-dispersion of the flame retardant. The homogenization process parameters were as follows: first, homogenize at a temperature of 35℃ and a working pressure of 40MPa for 10min; then, homogenize at a temperature of 55℃ and a working pressure of 90MPa for 30min. Among them, the flame retardant nitrogen-phosphorus agent YL-101 was provided by Dangshan Shilihe New Material Technology Co., Ltd.

[0030] (2) Add EPDM raw rubber (composed of EPDM 8550C and EPDM2650C mixed in a weight ratio of 1:1), magnesium oxide and stearic acid to the internal mixer according to the formula ratio, control the temperature at 70℃, and after mixing for 30 seconds, raise the top plug. (3) Add fast-pressed carbon black N550, flame retardant pre-dispersion and the balance of silane coupling agent to the internal mixer, mix to 100~110℃, raise the top plug twice in the middle to fully mix the materials evenly. (4) Add BIPB-40 peroxide and TMPTMA crosslinking agent to the internal mixer, mix at 115~120℃, and discharge the material; (5) Cool the mixture in a thin pass on the open mill, and then send it to the filter for filtration; (6) Cool the rubber compound to 15~25℃ and then package it.

[0031] Table 1. Amounts of each raw material component in Examples 1-3 and Comparative Example 1

[0032] Examples 4-8 Examples 4-8 respectively provide an EPDM flame-retardant water pipe material for charging piles and its preparation method.

[0033] The difference between the above embodiments and Embodiment 1 is that the types of EPDM raw rubber or flame retardants are different, as detailed below.

[0034] In Example 4: the EPDM raw rubber was composed of EPDM 8550C and EPDM 2650C in a weight ratio of 1.5:1.

[0035] In Example 5: the EPDM raw rubber was composed of EPDM 8550C and EPDM 2650C in a weight ratio of 3:1.

[0036] In Example 6: The flame retardant is composed of nitrogen-phosphorus agent YL-101 and aluminum hydroxide in a weight ratio of 5.5:6.

[0037] In Example 7: The flame retardant is composed of nitrogen-phosphorus agent YL-101 and aluminum hydroxide in a weight ratio of 6:5.

[0038] In Example 8: The flame retardant is composed of ammonium polyphosphate and aluminum hydroxide in a weight ratio of 4.5:7.

[0039] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0040] Examples 9-12 Examples 9-12 respectively provide an EPDM flame-retardant water pipe material for charging piles and its preparation method.

[0041] The difference between the above embodiment and embodiment 1 is that the process parameters of step (1) are different, as shown below.

[0042] In Example 9: The raw materials in step (1) are: the total amount of flame retardant (composed of nitrogen and phosphorus agent YL-101 and aluminum hydroxide compounded in a weight ratio of 4.5:7), the total amount of paraffin oil, and half of the amount of silane coupling agent A-172 (i.e., 2g).

[0043] In Example 10: the raw materials in step (1) are: the total amount of flame retardant (composed of nitrogen and phosphorus agent YL-101 and aluminum hydroxide in a weight ratio of 4.5:7), the total amount of paraffin oil, and one-quarter of the amount of silane coupling agent A-172 (i.e., 1g).

[0044] In Example 11: the raw materials in step (1) are: all the flame retardant (composed of nitrogen and phosphorus agent YL-101 and aluminum hydroxide in a weight ratio of 4.5:7), all the paraffin oil, and three-quarters of the amount of silane coupling agent A-172 (i.e., 3g).

[0045] In Example 12: In step (1), the process parameters for homogenization are: first, homogenize for 10 min at a temperature of 45℃ and a working pressure of 60MPa; then, homogenize for 30 min at a temperature of 45℃ and a working pressure of 70MPa.

[0046] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0047] Comparative Example Comparative Example 1 Comparative Example 1 provides an EPDM flame-retardant water pipe material for charging piles and its preparation method.

[0048] The difference between Comparative Example 1 and Example 1 is that the amounts of flame retardant, silane coupling agent A-172, and paraffin oil are different, as shown in Table 1.

[0049] All other process parameters in the above comparative examples are the same as those in Example 1.

[0050] Comparative Example 2 Comparative Example 2 provides an EPDM flame-retardant water pipe material for charging piles and its preparation method.

[0051] The difference between Comparative Example 2 and Example 1 is that the preparation method of the EPDM flame-retardant water pipe material for the charging pile is different. The flame retardant, paraffin oil, and a portion of the silane coupling agent A-172 were not mixed in advance to prepare a pre-dispersion; the details are as follows.

[0052] (1) Add EPDM raw rubber (composed of EPDM 8550C and EPDM2650C mixed in a weight ratio of 1:1), magnesium oxide and stearic acid to the internal mixer according to the formula ratio, control the temperature at 70℃, and raise the top plug after mixing for 30 seconds. (2) Add fast-pressed carbon black N550, flame retardant (composed of nitrogen and phosphorus agent YL-101 and aluminum hydroxide compounded in a weight ratio of 4.5:7), paraffin oil, and silane coupling agent A-172 to the internal mixer and mix to 100~110℃. Raise the top plug twice in the middle to fully mix the materials evenly. (3) Add BIPB-40 peroxide and TMPTMA crosslinking agent to the internal mixer, mix at 115~120℃, and discharge the material; (4) Cool the mixture in a thin pass on the open mill, and then send it to the filter for filtration; (5) Cool the rubber compound to 15~25℃ and then package it.

[0053] The amount of raw materials used in Comparative Example 2 is the same as that in Example 1.

[0054] The amount of raw materials used in Comparative Example 2 is the same as that in Example 1.

[0055] Comparative Examples 3-5 Comparative Examples 3-5 respectively provide an EPDM flame-retardant water pipe material for charging piles and its preparation method.

[0056] The difference between the above comparative example and Example 1 is as follows:

[0057] In Comparative Example 3, the flame retardant was composed of pentaerythritol phosphate and aluminum hydroxide in a weight ratio of 1:6.

[0058] In Comparative Example 4: the raw materials in step (1) are: all the flame retardant, all the paraffin oil, and one-eighth of the amount of silane coupling agent A-172 (i.e., 0.5g).

[0059] In Comparative Example 5: the raw materials in step (1) are: all the flame retardant, all the paraffin oil, and seven-eighths of the amount of silane coupling agent A-172 (i.e., 3.5g).

[0060] All other process parameters in the above comparative examples are the same as those in Example 1.

[0061] Performance testing Material properties: The properties of EPDM flame-retardant water pipe material for charging piles were determined under vulcanization conditions of 160℃×30min.

[0062] (1) Tensile strength: The tensile strength of the material shall be tested in accordance with the provisions of GB / T 528.

[0063] (2) Low temperature resilience: According to the test method of GB / T 7758, the low temperature resilience TR10 is tested.

[0064] (3) Flame retardancy rating: The flame retardancy rating of the material is tested in accordance with UL94.

[0065] (4) Anti-aging properties: Under the anti-aging test conditions of 80℃×100h, the tensile strength, low temperature resilience and flame retardant grade of the material are measured to evaluate the anti-aging properties.

[0066] Test results are shown in Table 2.

[0067] Table 2 Performance test results of EPDM flame-retardant water pipe material used in charging piles in the examples and comparative examples

[0068] As can be seen from the test results in Table 2 above, the flame-retardant water pipe material prepared by the technical solution provided in this application through optimized formula composition has excellent properties such as wide temperature range stability, mechanical-flame retardant synergy, sealing and damage resistance, and anti-aging performance.

[0069] By comparing the test results of Examples 1-3 and Comparative Example 1, it can be seen that the dosage of each raw material component has a significant impact on the performance of the flame-retardant water pipe material. In Comparative Example 1, the dosage of each raw material component was mismatched, resulting in a material with poor mechanical properties. In contrast, the present application, by precisely matching the dosage of each raw material component, produces a finished material with excellent performance.

[0070] By comparing the test results of Examples 1, 4-8, and Comparative Example 3, it can be seen that the ratio of EPDM8550C and EPDM2650C or the type of flame retardant in the EPDM raw rubber composition has a significant impact on the performance of flame-retardant water pipe materials. This application utilizes a phosphorus-nitrogen flame retardant and aluminum hydroxide compounded in a weight ratio of 4-6:5-8 to form a flame retardant, and EPDM raw rubber composed of a mixture of EPDM8550C and EPDM2650C in a weight ratio of 1-1.5:1-1.5 to simultaneously improve the overall performance of the material.

[0071] By comparing the test results of Examples 1, 9-12, and Comparative Examples 2, 4-5, it can be seen that the preparation method of flame-retardant water pipe material has a significant impact on the material performance. In this application, a flame-retardant pre-dispersion is prepared by first mixing and homogenizing all the flame retardant, all the paraffin oil, and one-half to two-thirds of the silane coupling agent A-172, and then adding it to the rubber reaction system. This can achieve excellent dispersion and good interfacial bonding of the flame retardant in the raw material reaction system, thereby endowing the material product with good mechanical properties, flame retardant properties, and anti-aging properties.

[0072] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. An EPDM flame-retardant water pipe material for charging piles, characterized in that, Specifically, it includes the following components in parts by weight: 100 parts EPDM raw rubber, 40-70 parts fast-extrusion carbon black N550, 90-140 parts flame retardant, 3-5 parts silane coupling agent A-172, 20-40 parts paraffin oil, 4-8 parts magnesium oxide, 0.5-1.5 parts stearic acid, 7-10 parts peroxide, and 1-3 parts co-crosslinking agent; The flame retardant is composed of phosphorus-nitrogen flame retardants and aluminum hydroxide in a weight ratio of 4~6:5~8.

2. The EPDM flame-retardant water pipe material for charging piles according to claim 1, characterized in that, Specifically, it includes the following components by weight: 100 parts EPDM raw rubber, 50-60 parts fast-extrusion carbon black N550, 100-130 parts flame retardant, 3.5-4.5 parts silane coupling agent A-172, 25-35 parts paraffin oil, 5-7 parts magnesium oxide, 0.7-1.2 parts stearic acid, 8-9 parts peroxide, and 1.5-2.5 parts crosslinking agent.

3. The EPDM flame-retardant water pipe material for charging piles according to claim 1, characterized in that, The EPDM raw rubber is composed of a mixture of EPDM 8550C and EPDM 2650C in a weight ratio of 1~1.5:1~1.

5.

4. The EPDM flame-retardant water pipe material for charging piles according to claim 1, characterized in that, The flame retardant is composed of a phosphorus-nitrogen flame retardant and aluminum hydroxide in a weight ratio of 4.5~5.5:6~7.

5. The EPDM flame-retardant water pipe material for charging piles according to claim 1, characterized in that, The phosphorus-nitrogen flame retardant is nitrogen-phosphorus agent YL-101.

6. The EPDM flame-retardant water pipe material for charging piles according to claim 1, characterized in that, The peroxide is BIPB-40; the crosslinking agent is TMPTMA.

7. A method for preparing EPDM flame-retardant water pipe material for charging piles as described in any one of claims 1 to 6, characterized in that, Specifically, the following steps are performed sequentially: (1) Mix all the flame retardant, all the paraffin oil, and one-quarter to three-quarters of the amount of silane coupling agent A-172 evenly to form a preliminary mixed slurry; then perform homogenization treatment to obtain a flame retardant pre-dispersion. (2) Add EPDM raw rubber, magnesium oxide and stearic acid to the internal mixer according to the formula ratio, control the temperature at 60~80℃, and after mixing for 20~40s, raise the top plug; (3) Add fast-pressed carbon black N550, flame retardant pre-dispersion and the balance of silane coupling agent to the internal mixer, mix to 100~110℃, raise the top plug 1~2 times in the middle to fully mix the materials evenly. (4) Add peroxide and crosslinking agent to the internal mixer, mix to 115~120℃, and discharge the material; (5) Cool the mixture in a thin pass on the open mill, and then send it to the filter for filtration; (6) Cool the rubber compound to 15~25℃ and then package it.

8. The method for preparing EPDM flame-retardant water pipe material for charging piles according to claim 7, characterized in that, The process parameters for step (1) are as follows: all the flame retardant, all the paraffin oil, and one-half to two-thirds of the silane coupling agent A-172 are added to a stirring tank at a temperature of 30~40℃ and a rotation speed of 50~100r / min, and stirred and mixed evenly to form a preliminary mixed slurry; then it is transferred to a homogenizer for homogenization to obtain a flame retardant pre-dispersion.

9. The method for preparing EPDM flame-retardant water pipe material for charging piles according to claim 7, characterized in that, The homogenization process parameters are as follows: first, homogenize for 5-20 minutes at a temperature of 30-40℃ and a working pressure of 30-50MPa; then, homogenize for 20-50 minutes at a temperature of 50-60℃ and a working pressure of 80-100MPa.

10. The application of the EPDM flame-retardant water pipe material for charging piles as described in any one of claims 1 to 6 in flame-retardant materials.

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