A nitrile rubber and ethylene propylene diene rubber blended material, a preparation method and application thereof

Abstract

This invention discloses a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber, its preparation method, and its application. It relates to the field of rubber material blending and modification technology. By weight, the blend comprises the following components: 100 parts nitrile rubber masterbatch; 30-50 parts EPDM rubber masterbatch; 0.4-0.6 parts stearic acid; 3-5 parts zinc oxide; 1-3 parts antioxidant; 10-20 parts plasticizer; 20-40 parts flame retardant; 10-30 parts modified basalt fiber; 10-30 parts carbon black; 2-6 parts sulfur; and 1-3 parts vulcanizing agent. The modified basalt fiber is a composite modified fiber obtained by modifying basalt fiber with a coupling agent and then combining it with carbon nanotube-based calcined products (BNCNTs). The invention also proposes a preparation method for this blend, solving the problem in existing nitrile rubber and EPDM rubber blends where significant polarity differences between the two lead to phase separation and insufficient interfacial bonding strength.

Description

Technical Field

[0001] This invention relates to the field of rubber material blending and modification technology, specifically to a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber, its preparation method, and its application. Background Technology

[0002] Nitrile butadiene rubber (NBR), a synthetic rubber containing polar cyano groups, exhibits excellent oil resistance, abrasion resistance, and mechanical strength due to the weak interaction between the cyano groups in its molecular chain and oily media. It is widely used in petrochemical, automotive parts, and other applications where it comes into contact with oily media. However, due to its molecular structure, NBR has extremely poor ozone aging resistance, is prone to oxidative degradation leading to product cracking, and has insufficient flame retardancy, posing safety hazards in high-temperature or open-flame environments. This significantly limits its application in outdoor settings and applications requiring high flame retardancy.

[0003] Ethylene propylene diene monomer (EPDM) rubber is a non-polar rubber copolymerized from ethylene, propylene, and a small amount of non-conjugated diene. Its saturated molecular chain structure endows it with excellent weather resistance, ozone resistance, and flame retardant properties, enabling it to work stably for long periods in complex outdoor environments and high-temperature conditions, and its production cost is relatively low. However, due to the lack of polar groups, EPDM rubber has significantly insufficient oil resistance and mechanical strength, making it unsuitable for use in sealing, transmission, and other components that come into contact with oily media.

[0004] To achieve complementary performance, blending nitrile rubber (NBR) with ethylene propylene diene monomer (EPDM) rubber has become an important technological direction in the rubber industry. By rationally controlling the blending ratio, it is possible to obtain composite rubber materials that combine excellent oil resistance, weather resistance, and mechanical strength, while optimizing the overall cost of the products. This has significant application value in key areas such as automotive sealing strips, engine compartment hoses, and industrial seals. However, the polarity of NBR and the non-polarity of EPDM rubber differ significantly, resulting in extremely poor compatibility when blended. The interfacial tension between the two phases is high, and the bonding strength is weak. Phase separation easily occurs during mixing, vulcanization, and use, causing a significant decrease in the mechanical properties and media resistance stability of the blended rubber, failing to achieve the expected performance. This problem has become the core bottleneck restricting the industrial application of this blending technology.

[0005] To address the aforementioned compatibility issues, existing technologies have proposed various improvement schemes, including adding compatibilizers, optimizing the vulcanization system, employing dynamic vulcanization, and special processing techniques. Among these, the compatibilizer method introduces compatibility mediators such as maleic anhydride-grafted ethylene propylene diene monomer (EPDM-g-MAH) and chlorinated polyethylene (CPE) to reduce the interfacial energy between the two phases. However, the introduction of compatibilizers often sacrifices some inherent properties of the rubber material, and compatibility is significantly affected by the blending ratio. The dynamic vulcanization method, by crosslinking one phase of rubber during blending to form a micron-scale dispersed phase, can improve phase stability, but the process control is complex and places stringent requirements on equipment shear forces.

[0006] Patent application CN109135072A discloses a method for modifying blended rubber based on supercritical carbon dioxide technology. This technology involves treating EPDM / nitrile rubber with supercritical carbon dioxide before vulcanization. Utilizing the unique solubility and diffusion properties of supercritical fluids, the blended rubber foams and expands, increasing the contact area between the two phases and improving compatibility and co-vulcanization performance. While this technology has shown some effectiveness under laboratory conditions, it suffers from inherent technical drawbacks: supercritical carbon dioxide technology requires high pressure and specific temperature environments, placing extremely high demands on the pressure resistance and sealing of equipment, resulting in high equipment investment costs; furthermore, the temperature and pressure parameters during the supercritical treatment process are highly sensitive to precision control, leading to cumbersome equipment maintenance procedures and significant energy consumption, making it difficult to meet the needs of large-scale industrial production and limiting its widespread application in actual production.

[0007] In summary, there is still a lack of a technical solution for nitrile rubber / ethylene propylene diene monomer (EPDM) blends that balance modification effects, process simplicity, and industrial feasibility. How to effectively improve the compatibility of the two rubbers and obtain blended rubber materials with balanced performance while reducing technical barriers and production costs has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber, its preparation method, and its application, in order to solve the technical problem in the prior art where the blend of nitrile rubber and EPDM rubber is prone to phase separation due to the significant difference in polarity between the two, resulting in insufficient interfacial bonding strength of the blend.

[0009] This invention is achieved through the following technical solution:

[0010] A blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber, comprising the following components by weight:

[0011] 100 parts of nitrile rubber masterbatch;

[0012] 30-50 parts of EPDM rubber masterbatch;

[0013] Stearic acid 0.4~0.6 parts;

[0014] 3-5 parts zinc oxide;

[0015] Anti-aging agent 1-3 parts;

[0016] Plasticizer 10-20 parts;

[0017] 20-40 parts flame retardant;

[0018] 10-30 parts of modified basalt fiber;

[0019] 10-30 parts carbon black;

[0020] Sulfur 2-6 parts;

[0021] 1-3 parts of vulcanizing agent;

[0022] The modified basalt fiber is a composite modified fiber obtained by modifying basalt fiber with a coupling agent and then combining it with carbon nanotube-based calcined products (BNCNTs).

[0023] Furthermore, the plasticizer is an aryl / alkylaryl phosphate or an alkyl phosphate. Triphenyl phosphate (TPP) is preferred, as it has good compatibility, flame retardancy, and electrical insulation properties.

[0024] Furthermore, the acrylonitrile content of the nitrile rubber is >30%; the ethylene content of the EPDM rubber is >60%.

[0025] Furthermore, the antioxidant is selected from one of 4010Na, 4020, and DTPD.

[0026] Furthermore, the vulcanizing agent is selected from one of TMTD, TBzTD, and DPTT.

[0027] Furthermore, the modified basalt fiber is obtained by the following steps:

[0028] a. Cut basalt fibers into 2-4 mm short fibers, disperse them, and dry them at 110-130℃ for 2-4 h. After cooling, add 0.5-1.5 wt% coupling agent solution, stir at room temperature for 1-2 h, filter, and dry at 70-90℃ for 2-4 h to obtain preliminary modified basalt fibers.

[0029] b. Disperse carbon nanotubes and boric acid in deionized water at a mass ratio of 2:4~6, sonicate for 0.5~1.5h, centrifuge and air dry, then mix carbon nanotubes, boric acid and ammonium chloride at a mass ratio of 2:4~6:8~12, heat to 700~900℃ at a rate of 5~15℃ / min under an inert gas atmosphere for 20~40min, hold for 1~3h, and cool with the furnace to obtain BNCNTs;

[0030] c. Dissolve BNCNTs and preliminarily modified basalt fibers in an ethanol-water solution at a mass ratio of 1:20~28, alternately sonicate for 5~15 min and stir in a water bath at 60~100℃ for 5~15 min, repeat the filtration and cooling process to obtain modified basalt fibers.

[0031] Furthermore, in step a, the basalt fibers have a diameter ≤12μm and a density of approximately 2.6~2.8g / cm³. 3 Tensile strength greater than 1000MPa.

[0032] Furthermore, in step a, the coupling agent is selected from one of KH560, KH550, and KH792; the solvent of the coupling agent solution is a mixed solution of ethanol and deionized water.

[0033] In step c, the ultrasonic frequency is 40~100kHz.

[0034] A method for preparing a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber as described above includes the following steps:

[0035] S1. Plasticize the nitrile rubber masterbatch on a two-roll mill at 50-60℃ and 50-100rpm for 5-10 minutes;

[0036] S2. Add EPDM rubber masterbatch and mix for 4-6 minutes at 50-60℃ and 40-60 rpm on a two-roll mill.

[0037] S3. Stearic acid, zinc oxide, antioxidant and plasticizer are added in sequence. After each addition of a component, the mixture is mixed for 4 to 6 minutes on a two-roll mill at 50 to 60°C and 40 to 60 rpm.

[0038] S4. Add flame retardant and mix for 7-9 minutes on a two-roll open mill at 60-70℃ and 40-60 rpm.

[0039] S5. Add modified basalt fiber and carbon black. After each addition of a component, mix them for 7-9 minutes on a two-roll mill at 65-75°C and 40-60 rpm.

[0040] S6. Add the premixed sulfur and vulcanizing agent, and mix them on a two-roll mill at 35~45℃ and 40~60rpm for 4~6 minutes to obtain the compound.

[0041] S7. Pass the compounded rubber through a two-roll mill 8-12 times, then perform the first stage of vulcanization by hot pressing in a flat vulcanizing machine, and then perform the second stage of vulcanization to obtain the blended material.

[0042] Furthermore, in step S7, the hot-pressing temperature of the first stage of vulcanization is 130~170℃, the pressure is 5~15MPa, and the vulcanization time is determined based on the vulcanization characteristic value TC90 measured by the rotorless vulcanizer.

[0043] Furthermore, in step S7, the temperature of the second-stage vulcanization is 140~180℃, and the vulcanization time is 0.5~1.5h.

[0044] The application of a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber in sealing of aviation hydraulic systems and rubber products for cable sheathing, wherein the blend of nitrile rubber and EPDM rubber is the aforementioned material, or a blend of nitrile rubber and EPDM rubber prepared by the aforementioned preparation method.

[0045] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0046] I. This invention proposes a blend of nitrile butadiene rubber (NBR) and ethylene propylene diene monomer (EPDM) rubber, which can significantly improve the mechanical properties of the blended rubber. Basalt fibers (BFs) are surface-modified using coupling agents such as KH560, and then composited with carbon nanotube-based calcined products (BNCNTs) to obtain a BFs-BNCNTs composite filler. The tensile strength of the NBR / EPDM blended rubber filled with this filler can reach 17.1~17.9 MPa. Simultaneously, relying on the synergistic effect of van der Waals forces and charge transfer, the composite filler achieves a tight bond with the rubber matrix at both the molecular and macroscopic scales, further enhancing the overall mechanical properties of the material. This NBR / EPDM blend can be used in the preparation of flame-retardant and wear-resistant rubber products.

[0047] II. This invention proposes a blend of nitrile butadiene rubber (NBR) and ethylene propylene diene monomer (EPDM) rubber, which can improve the interfacial compatibility of the blend system and reduce the risk of phase separation. The specific surface area of ​​the BFs-BNCNTs composite filler is significantly increased, enabling it to form a tight bond with the NBR / EPDM blend rubber through van der Waals forces, and also to form a stable bond with the blend rubber through charge transfer of pyridine nitrogen and boron elements on the filler surface. This effectively reduces the risk of phase separation of the blend rubber at the interfacial bonding level and improves the structural stability of the material.

[0048] Thirdly, this invention proposes a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber, which can impart excellent flame retardant properties to the blend. The boron element in BFs-BNCNTs can generate boron oxides under high-temperature conditions. This product can synergistically interact with flame retardants such as SFR-3B to construct a multi-layered flame retardant barrier. Simultaneously, BFs themselves possess inert properties, which can further inhibit the spread of flame and improve the flame retardant safety performance of the material.

[0049] IV. This invention proposes a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber, which can significantly enhance the wear resistance of the material. Utilizing the high strength and high modulus properties of BFs-BNCNTs, combined with the reinforcing effect of carbon black (such as N330), a hard phase dispersion network can be formed in the rubber matrix, effectively resisting stress concentration problems that occur during wear, thereby greatly improving the wear resistance of the blended rubber.

[0050] V. In this invention, a method for preparing a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber is proposed, which is beneficial for preparing materials that have oil resistance, wear resistance, weather resistance, heat resistance, excellent mechanical strength, and flame retardant properties, and the material properties are stable. Attached Figure Description

[0051] Figure 1 This is a scanning electron microscope image of the nitrile rubber and ethylene propylene diene monomer (EPDM) rubber blend material of the present invention. Detailed Implementation

[0052] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0053] In the following examples, the modified basalt fibers used were all obtained using the following preparation method:

[0054] a. Basalt fibers (BFs) with a diameter of less than 12 μm are cut into short fibers of 2-4 mm. After being broken up by a crusher, they are dried in a forced-air oven at 110-130℃ for 2-4 hours to remove surface moisture. After cooling, 0.5-1.5 wt% of KH560 coupling agent solution is added. After sealing, the mixture is stirred at room temperature for 1-2 hours, filtered, and then dried in an oven at 70-90℃ for 2-4 hours. After removal, it is sealed and stored to obtain the preliminary modified basalt fiber BFs-KH560.

[0055] b. Disperse carbon nanotubes (CNTs) with an outer diameter of 4-6 nm and boric acid (H3BO3) in 40-60 mL of deionized water at a mass ratio of 2:5, and sonicate for 0.5-1.5 h. After centrifugation and cooling, mix the sample with ammonium chloride at a mass ratio of (NH4Cl) CNTs:H3BO3:NH4Cl=2:5:10, place it in a quartz boat, put it in a tube furnace, and purge it with an argon atmosphere for 20-40 min to ensure that the air in the tube furnace is completely removed. Then, heat it to 700-900℃ at a rate of 5-15℃ / min, hold it for 1-3 h, and cool it to room temperature with the furnace to obtain boron and nitrogen co-doped carbon nanotubes, denoted as BNCNTs.

[0056] c. Dissolve BNCNTs and BFs-KH560 in a mixture of ethanol (25 mL) and deionized water (25 mL) at a certain ratio (BNCNTs: BFs-KH560 = 1:24). After sonication for 5-15 min, place the mixture in a water bath at 60-100℃ and stir magnetically for 5-15 min. Repeat the sonication and water bath cycles 4-8 times each. After filtration and cooling, obtain BFs-BNCNTs.

[0057] In this invention, the coupling agent can be selected from one of KH560, KH550, and KH792. In the following embodiments, KH560 is used as an example to further illustrate this scheme.

[0058] In this invention, the antioxidant can be selected from one of 4010Na, 4020, and DTPD. In the following examples, 4010Na is used as an example for testing.

[0059] In this invention, the acrylonitrile content of the nitrile rubber masterbatch is >30%, and NBR1032, NBR1041, NBR1042, and NBR1051 can be selected. In the following examples, NBR1032 is used as an example for testing.

[0060] In this invention, the ethylene content of the EPDM masterbatch is >60%, and one of EPDM7001, EPDM5600, and EPDM5702 can be selected. In the following examples, EPDM5702 is used as an example for testing.

[0061] In this invention, the plasticizer is selected from aryl / alkylaryl phosphates or alkyl phosphates, preferably triphenyl phosphate (TPP), which has good compatibility, flame retardancy, and electrical insulation properties. The following examples use TPP, which has both flame retardant and plasticizing functions, as an example for testing.

[0062] Extensive testing has verified that in the rubber material formulation of this invention, when the amount of TPP is less than 10 parts, the Mooney viscosity of the rubber compound is too high, resulting in poor processing performance; when it is more than 20 parts, it leads to a decrease in mechanical properties such as tensile strength and abrasion resistance. Therefore, in the following embodiments, the preferred amount of TPP is 15 parts.

[0063] In the rubber material formulation of this invention, carbon black serves both as a colorant and a reinforcing agent. When its dosage is less than 10 parts, the reinforcing effect is insufficient, and the material strength is low; when the dosage is more than 30 parts, agglomeration easily occurs, and the dispersibility deteriorates. Therefore, in the embodiments, the preferred dosage of carbon black is 20 parts.

[0064] Example 1

[0065] A method for preparing a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber includes the following steps:

[0066] S1. Prepare the raw materials according to the weight ratio of each raw material in Table 1 below, and set them aside for later use;

[0067] Table 1

[0068]

[0069] S2. Plasticize the nitrile rubber masterbatch on a two-roll mill at 55°C and 50 rpm for 5 minutes.

[0070] S3. Add EPDM rubber masterbatch and mix for 5 minutes on a two-roll mill at 55°C and 50 rpm.

[0071] S4. Stearic acid, zinc oxide, antioxidant, and triphenyl phosphate plasticizer are added in sequence. After each component is added, the mixture is kneaded for 5 minutes on a two-roll mill at 55°C and 50 rpm.

[0072] S5. Add flame retardant and mix for 8 minutes on a two-roll open mill at 65°C and 50 rpm.

[0073] S6. Add modified basalt fiber and carbon black. After each addition of a component, mix for 8 minutes on a two-roll mill at 70°C and 50 rpm.

[0074] S7. Add premixed sulfur and tetramethylthiuram disulfide vulcanizing agent, and mix for 5 minutes on a two-roll mill at 40°C and 50 rpm to obtain NBR / EPDM compound.

[0075] S8. After passing the NBR / EPDM compound through a two-roll mill 10 times, the compound is sheeted and hot-pressed into samples using a flat vulcanizing machine. The vulcanization temperature is 150℃, and the vulcanization time is determined based on the vulcanization characteristic parameter TC90 measured by a rotorless vulcanizer (TC90 is tested according to GB / T 16584 and is the time required for the rubber to reach 90% of its maximum shear torque, usually considered the optimal vulcanization time). The vulcanization pressure is 10MPa. Subsequently, a two-stage vulcanization is carried out at 160℃ for 1 hour to finally obtain the NBR / EPDM blend vulcanizate material.

[0076] Example 2

[0077] A method for preparing a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber includes the following steps:

[0078] S1. Prepare the raw materials according to the weight ratio of each raw material in Table 2 below, and set aside for later use;

[0079] Table 2

[0080]

[0081] S2. Plasticize the nitrile rubber masterbatch on a two-roll mill at 55°C and 50 rpm for 5 minutes.

[0082] S3. Add EPDM rubber masterbatch and mix for 5 minutes on a two-roll mill at 55°C and 50 rpm.

[0083] S4. Stearic acid, zinc oxide, antioxidant, and triphenyl phosphate plasticizer are added in sequence. After each component is added, the mixture is kneaded for 5 minutes on a two-roll mill at 55°C and 50 rpm.

[0084] S5. Add flame retardant and mix for 8 minutes on a two-roll open mill at 65°C and 50 rpm.

[0085] S6. Add modified basalt fiber and carbon black. After each addition of a component, mix for 8 minutes on a two-roll mill at 70°C and 50 rpm.

[0086] S7. Add premixed sulfur and tetramethylthiuram disulfide vulcanizing agent, and mix for 5 minutes on a two-roll mill at 40°C and 50 rpm to obtain NBR / EPDM compound.

[0087] S8. After passing the NBR / EPDM compound through a two-roll mill 10 times, sheet it out and hot-press it into samples using a flat vulcanizing machine. The vulcanization temperature was 150℃, the vulcanization time was determined based on the vulcanization characteristic parameter TC90 measured by a rotorless vulcanizing instrument, and the vulcanization pressure was 10MPa. Subsequently, a two-stage vulcanization process was performed at 160℃ for 1 hour to finally obtain the NBR / EPDM blend vulcanizate material. (Reference) Figure 1 , Figure 1 This is a scanning electron microscope image of a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber.

[0088] Example 3

[0089] A method for preparing a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber includes the following steps:

[0090] S1. Prepare the raw materials according to the weight ratio of each raw material in Table 3 below, and set aside for later use;

[0091] Table 3

[0092]

[0093] S2. Plasticize the nitrile rubber masterbatch on a two-roll mill at 55°C and 50 rpm for 5 minutes.

[0094] S3. Add EPDM rubber masterbatch and mix for 5 minutes on a two-roll mill at 55°C and 50 rpm.

[0095] S4. Stearic acid, zinc oxide, antioxidant, and triphenyl phosphate plasticizer are added in sequence. After each component is added, the mixture is kneaded for 5 minutes on a two-roll mill at 55°C and 50 rpm.

[0096] S5. Add flame retardant and mix for 8 minutes on a two-roll open mill at 65°C and 50 rpm.

[0097] S6. Add modified basalt fiber and carbon black. After each addition of a component, mix for 8 minutes on a two-roll mill at 70°C and 50 rpm.

[0098] S7. Add premixed sulfur and tetramethylthiuram disulfide vulcanizing agent, and mix for 5 minutes on a two-roll mill at 40°C and 50 rpm to obtain NBR / EPDM compound.

[0099] S8. After passing the NBR / EPDM compound through a two-roll mill 10 times, the compound is sheeted and hot-pressed into samples using a flat vulcanizing machine. The vulcanization temperature is 150℃, the vulcanization time is determined based on the vulcanization characteristic parameter TC90 measured by a rotorless vulcanizing instrument, and the vulcanization pressure is 10MPa. Subsequently, a two-stage vulcanization is carried out at 160℃ for 1 hour to finally obtain the NBR / EPDM blend vulcanizate material.

[0100] Comparative Example 1

[0101] The only difference between this comparative example and Example 2 is that no modified basalt fiber was added. The specific raw material ratio is shown in Table 4.

[0102] Table 4

[0103]

[0104] This comparative example uses the same preparation method as Example 2 to prepare a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber.

[0105] Comparative Example 2

[0106] The only difference between this comparative example and Example 2 is that a small amount of modified basalt fiber was added. The specific raw material ratio is shown in Table 5.

[0107] Table 5

[0108]

[0109] This comparative example uses the same preparation method as Example 2 to prepare a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber.

[0110] Comparative Example 3

[0111] The only difference between this comparative example and Example 2 is that 32 parts of modified basalt fiber were added. The specific raw material ratio is shown in Table 6.

[0112] Table 6

[0113]

[0114] This comparative example uses the same preparation method as Example 2 to prepare a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber.

[0115] The nitrile rubber and EPDM rubber blends obtained in Examples 1-3 and Comparative Examples 1-3 were then tested, and the test results are shown in Table 7.

[0116] The relevant testing methods, reference standards, and testing equipment are as follows:

[0117] The hardness test method is based on GB / T 531.1, and the equipment is a digital Shore A hardness tester (SHYC80A); the tensile stress-strain property (elongation at break and tensile strength) test method is based on GB / T 528, and the equipment is an electronic universal testing machine (E43.104); the abrasion resistance (wear loss) test method is based on GB / T 9867, and the equipment is a rotary roller abrasion tester (HY-766B); the flammability (flame retardancy) test method is based on GB / T 10707, and the equipment is an oxygen index tester (ZY6155).

[0118] Table 7

[0119]

[0120] As shown in Table 7, the hardness of the nitrile rubber and EPDM rubber blends prepared in Examples 1-3 are all >65 Shore A, the elongation at break is all >550%, and the tensile strength is all >17 MPa, indicating that the blends prepared using this formulation possess excellent comprehensive mechanical properties. Compared to Comparative Example 1 without BFs-BNCNTs, its elongation at break is lower than 550% and its tensile strength is lower than 17 MPa, showing significantly inferior mechanical properties compared to the examples. This fully demonstrates that the addition of BFs-BNCNTs in this formulation plays a crucial role in improving the mechanical properties of the blends. Such nitrile rubber and EPDM rubber blends can be used in seals for aerospace hydraulic systems and in rubber products for cable sheaths.

[0121] The abrasion loss of the nitrile rubber and ethylene propylene diene monomer (EPDM) blends prepared in Examples 1-3 was all less than 100 mm. 3 This indicates that the blend material prepared using this formulation has excellent wear resistance.

[0122] The flame retardant performance of the nitrile rubber and ethylene propylene diene monomer (EPDM) blends prepared in Examples 1-3 all reached V-0, indicating that the blends prepared using this formulation have excellent flame retardant properties.

[0123] To further investigate the role of BFs-BNCNTs in the formulation of this invention, comparative example 2 (with a small amount of BFs-BNCNTs added) and comparative example 3 (with an excessive amount of BFs-BNCNTs added) were designed for comparison with Example 2. Table 7 shows that adding a small amount of BFs-BNCNTs can slightly enhance the mechanical properties of the blend and reduce wear, but the overall mechanical properties are not excellent enough (e.g., hardness is 64 Shore A), limiting its application areas. Adding an excessive amount of BFs-BNCNTs increases the risk of fiber agglomeration in the blend, leading to decreased mechanical properties of the interfacial defect material and accelerated wear.

[0124] Furthermore, as can be seen from the comparison between Comparative Example 1 and Examples 1-3, and Comparative Examples 2 and 3,

[0125] The addition of BFs-BNCNTs components can improve flame retardant properties.

[0126] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber, characterized in that, By weight, it comprises the following components: 100 parts of nitrile rubber masterbatch; 30-50 parts of EPDM rubber masterbatch; Stearic acid 0.4~0.6 parts; 3-5 parts zinc oxide; Anti-aging agent 1-3 parts; Plasticizer 10-20 parts; 20-40 parts flame retardant; 10-30 parts of modified basalt fiber; 10-30 parts carbon black; Sulfur 2-6 parts; 1-3 parts of vulcanizing agent; The modified basalt fiber was obtained using the following steps: a. Cut basalt fibers into 2-4 mm short fibers, disperse them, and dry them at 110-130℃ for 2-4 h. After cooling, add 0.5-1.5 wt% coupling agent solution, stir at room temperature for 1-2 h, filter, and dry at 70-90℃ for 2-4 h to obtain preliminary modified basalt fibers. b. Disperse carbon nanotubes and boric acid in deionized water at a mass ratio of 2:4~6, sonicate for 0.5~1.5h, centrifuge and air dry, then mix carbon nanotubes, boric acid and ammonium chloride at a mass ratio of 2:4~6:8~12, heat to 700~900℃ at a rate of 5~15℃ / min under an inert gas atmosphere for 20~40min, hold for 1~3h, and cool with the furnace to obtain BNCNTs; c. Dissolve BNCNTs and preliminarily modified basalt fibers in an ethanol-water solution at a mass ratio of 1:20~28, alternately sonicate for 5~15 min and stir in a water bath at 60~100℃ for 5~15 min, repeat the filtration and cooling process to obtain modified basalt fibers.

2. The nitrile rubber and ethylene propylene diene monomer (EPDM) blend material according to claim 1, characterized in that: The acrylonitrile content of the nitrile rubber is >30%; the ethylene content of the ethylene propylene diene monomer (EPDM) rubber is >60%.

3. The nitrile rubber and ethylene propylene diene monomer (EPDM) rubber blend material according to claim 1, characterized in that: The antioxidant is selected from one of 4010Na, 4020, and DTPD.

4. The nitrile rubber and ethylene propylene diene monomer (EPDM) rubber blend material according to claim 1, characterized in that: The vulcanizing agent is selected from TMTD, TBzTD, and DPTT.

5. The nitrile rubber and ethylene propylene diene monomer (EPDM) rubber blend material according to claim 1, characterized in that: In step a, the basalt fibers have a diameter ≤12μm and a density of 2.6~2.8g / cm³. 3 Tensile strength greater than 1000MPa.

6. The nitrile rubber and ethylene propylene diene monomer (EPDM) rubber blend material according to claim 1, characterized in that: In step a, the coupling agent is selected from one of KH560, KH550, and KH792; the solvent of the coupling agent solution is a mixed solution of ethanol and deionized water. In step c, the ultrasonic frequency is 40~100kHz.

7. A method for preparing a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber as described in claim 1, characterized in that, Includes the following steps: S1. Plasticize the nitrile rubber masterbatch on a two-roll mill at 50~60℃ and 50~100rpm for 5~10min; S2. Add EPDM rubber masterbatch and mix on a two-roll mill at 50-60℃ and 40-60rpm for 4-6 minutes. S3. Add stearic acid, zinc oxide, antioxidant, and plasticizer in sequence. After each addition of a component, mix on a two-roll mill at 50-60°C and 40-60 rpm for 4-6 minutes. S4. Add flame retardant and mix for 7-9 minutes on a two-roll open mill at 60-70℃ and 40-60 rpm. S5. Add modified basalt fiber and carbon black. After each addition of a component, mix them for 7-9 minutes on a two-roll mill at 65-75°C and 40-60 rpm. S6. Add the premixed sulfur and vulcanizing agent, and mix them on a two-roll mill at 35~45℃ and 40~60rpm for 4~6 minutes to obtain the compound. S7. Pass the compounded rubber through a two-roll mill 8-12 times, then perform the first stage of vulcanization by hot pressing in a flat vulcanizing machine, and then perform the second stage of vulcanization to obtain the blended material.

8. The preparation method according to claim 7, characterized in that: In step S7, the hot pressing temperature of the first stage of vulcanization is 130~170℃, and the pressure is 5~15MPa.

9. The preparation method according to claim 7, characterized in that: In step S7, the temperature of the two-stage vulcanization is 140~180℃, and the vulcanization time is 0.5~1.5h.

10. The application of a blend of nitrile rubber and ethylene propylene diene monomer (EPDM) rubber in seals for aerospace hydraulic systems and rubber products for cable sheaths, characterized in that: The nitrile rubber and ethylene propylene diene monomer (EPDM) blend material is the material according to any one of claims 1 to 6, or the nitrile rubber and EPDM blend material prepared by any one of the preparation methods in claims 7 to 9.

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