Refrigerant-resistant sealing ring for new energy automobile air conditioner and preparation method of refrigerant-resistant sealing ring

Abstract

The invention relates to the technical field of automobile air conditioner sealing, and particularly discloses a refrigerant-resistant sealing ring for a new energy automobile air conditioner and a preparation method of the refrigerant-resistant sealing ring. The refrigerant-resistant sealing ring for the new energy automobile air conditioner is prepared from nitrile rubber, a vulcanization system, carbon black, graphene nanosheets, a softening plasticizer, a processing aid and a thermoplastic elastomer. Wherein the carbon black and the graphene nanosheets are used as a reinforcing filler of the nitrile rubber, the carbon black and the graphene nanosheets have a remarkable synergistic enhancement effect, the reinforcing effect of the rubber is improved by adding the carbon black, and the mechanical property and the medium-resistant stability of the material can be remarkably improved by adding a small amount of the graphene nanosheets. In addition, thionyl chloride and 3-(4-(hydroxymethyl) phenoxy) phthalonitrile are adopted to perform pretreatment on the graphene nanosheets, so that the dispersity of the graphene nanosheets in the rubber is effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of automobile air-conditioning sealing, and in particular to a refrigerant-resistant sealing ring for a new energy automobile air-conditioning and a preparation method thereof. Background Art

[0002] At present, most of the automotive air-conditioning seals on the market are made of traditional rubber materials. Although they can meet the sealing requirements of general automotive air-conditioning systems, in new energy vehicle air-conditioning systems, due to the use of new environmentally friendly refrigerants, traditional sealing materials often show poor media resistance.

[0003] Environmentally friendly refrigerants are highly corrosive and permeable. Traditional sealing rings are prone to swelling, hardening or cracking when in long-term contact with environmentally friendly refrigerants. Therefore, in order to solve this problem, oil-resistant and chemical-resistant fluororubber or nitrile rubber is usually used as the sealing ring material. Among them, the fluorine element of fluororubber forms a strong chemical bond in the chemical structure, which makes it have excellent resistance to chemical corrosion, but this type of material generally has problems such as difficult processing and high cost; while nitrile rubber has better tolerance to grease and refrigerant media by introducing cyanide groups into its molecular chain, but it has not completely overcome the aging problem of refrigerant resistance. In extreme environments, the performance of nitrile rubber may be reduced, resulting in sealing failure. Summary of the invention

[0004] In order to improve the corrosion resistance and durability of the sealing ring and reduce the failure problem of the sealing ring in extreme environments, the present application provides a refrigerant-resistant sealing ring for new energy vehicle air conditioners and a preparation method thereof.

[0005] In the first aspect, the present application provides a refrigerant-resistant sealing ring for a new energy vehicle air conditioner, which adopts the following technical solution: A refrigerant-resistant sealing ring for a new energy vehicle air conditioner is prepared from the following raw materials in parts by weight: 60-70 parts of nitrile rubber, 10-15 parts of vulcanization system, 16-18 parts of carbon black, 2-4 parts of graphene nanosheets, 6-10 parts of softening plasticizer, 1-2 parts of processing aid, and 8-12 parts of thermoplastic elastomer TPE; The graphene nanosheets are graphene nanosheets pretreated with thionyl chloride and 3-(4-(hydroxymethyl)phenoxy)phthalonitrile, and the weight ratio of the graphene nanosheets, thionyl chloride and 3-(4-(hydroxymethyl)phenoxy)phthalonitrile is 1:(1.2-1.4):(0.1-0.3).

[0006] Preferably, the acrylonitrile content in the nitrile rubber is 28-32%.

[0007] By adopting the above technical scheme, the sealing ring of the present application adopts nitrile rubber as matrix material, and nitrile rubber itself has good oil resistance and chemical resistance, and uses carbon black and graphene nanosheets as reinforcing fillers, and carbon black and graphene nanosheets have significant synergistic enhancement effect, and at the same time, introduce thermoplastic elastomer TPE as blending and modifying component, improve the dimensional stability and resilience of sealing ring in high and low temperature cycle change. Wherein, the addition of carbon black improves the reinforcing effect of rubber, and adds a small amount of graphene nanosheets, can significantly improve the mechanical properties and medium-resistant stability of material, avoid swelling, hardening or cracking phenomenon in material, and, graphene nanosheets can reduce the material easy aging, hardening problem caused by excessive addition of carbon black. And, after the pretreatment of thionyl chloride and 3-(4-(hydroxymethyl) phenoxy) phthalonitrile, graphene nanosheets can form good interface bonding with rubber matrix, effectively prevent the penetration of refrigerant molecules, significantly enhance the ability of sealing ring to resist the erosion of refrigerant of new energy vehicle air conditioner, ensure the sealing and reliability of air conditioning system.

[0008] Preferably, the graphene nanosheets are pretreated by the following method: (1) adding graphene nanosheets to mixed acid, ultrasonically dispersing at 45-55° C. for 3-4 hours, washing to neutrality, and drying to obtain oxidized graphene nanosheets; (2) mixing the oxidized graphene nanosheets with thionyl chloride, adding a catalyst, stirring and refluxing at 45-55° C. for 2-3 hours, and distilling and recovering the thionyl chloride after the reaction to obtain chlorinated graphene nanosheets; (3) Dissolving 3-(4-(hydroxymethyl)phenoxy)phthalonitrile in a solvent, mixing with the chlorinated graphene nanosheets, stirring and reacting at room temperature for 3-4 hours, washing 2-3 times, and vacuum drying to obtain pretreated graphene nanosheets.

[0009] Preferably, the mixed acid in step (1) is prepared by mixing concentrated H2SO4:HNO3 in a volume ratio of 3:1.

[0010] By adopting the above technical scheme, because graphene nano sheet has larger surface area, cause graphene nano sheet to be easily stacked together, reunion is serious, thus cause the performance degradation of material.Therefore, by thionyl chloride and 3-(4-(hydroxymethyl) phenoxy) phthalonitrile, graphene nano sheet is pre-treated, graphene nano sheet is changed into disordered state, to reduce the reunion of graphene nano sheet, thus can be evenly dispersed in rubber matrix.And, there is cyano group on the surface of modified graphene nano sheet, can react with acrylonitrile butadiene rubber, make graphene nano sheet and acrylonitrile butadiene rubber generation chemical bonding action, form organic-inorganic hybrid reinforcement system, acrylonitrile butadiene rubber plays a good reinforcement effect.

[0011] Preferably, the graphene nanosheet has a diameter of 5-10 μm, a thickness of 10-20 nm, and a specific surface area of ​​120-150 m 2 / g.

[0012] By adopting the above technical solution, graphene nanosheets with a diameter of 5-10μm and a thickness of 10-20nm can be more evenly dispersed in the rubber matrix, reducing the agglomeration state of the graphene nanosheets, reducing gaps and defects, and improving the density of the sealing ring, so that the sealing ring has excellent corrosion resistance to resist the erosion of the refrigerant.

[0013] Preferably, the catalyst in step (2) and the solvent in step (3) are both DMF.

[0014] By adopting the above technical solution, N,N-dimethylformamide is used as a carrier or solvent of the catalyst in the reaction, providing a contact area between the reactants and enhancing the catalytic effect. Among them, N,N-dimethylformamide contains aldehyde groups and dimethylamine groups in its molecular structure, which serve as functional group donors in the reaction.

[0015] Preferably, the vulcanization system includes a vulcanizing agent and an accelerator, wherein the vulcanizing agent is obtained by mixing CZ and DZ in a weight ratio of (3-4): (4-6); and the accelerator is DM.

[0016] By adopting the above technical solution, the vulcanization system can form a uniform and stable cross-linked network structure during the rubber vulcanization process, thereby improving the strength and elasticity of the sealing ring. Among them, the appropriate amount of CZ and DZ mixed can ensure that the vulcanization reaction is complete, and will not cause excessive cross-linking and cause the material to become brittle and hard. In addition, adding accelerator DM can accelerate the vulcanization reaction and shorten the vulcanization time.

[0017] Preferably, the softening plasticizer is bio-based DOTP.

[0018] By adopting the above technical solutions, compared with traditional petroleum-based plasticizers, bio-based DOTP is easier to be decomposed by microorganisms and has a lower risk of long-term pollution to the environment.

[0019] Preferably, the processing aid includes at least one of an antioxidant, an anti-aging agent, a curing agent, and a release agent.

[0020] By adopting the above technical solution and adding the above processing aids, an auxiliary role is played, so that the sealing ring material is more in line with actual needs and the practical performance of the sealing ring is improved.

[0021] In the second aspect, the present application provides a method for preparing a refrigerant-resistant sealing ring for a new energy vehicle air conditioner, which adopts the following technical solution: A method for preparing a refrigerant-resistant sealing ring for a new energy vehicle air conditioner comprises the following steps: S1: weighing raw materials according to the component ratio, melt-mixing nitrile rubber, thermoplastic elastomer TPE, carbon black, graphene nanosheets, softening plasticizer and processing aid at 145-155°C to obtain a premix; then, mixing the premix with a vulcanization system, vulcanizing at 130-170°C, and extruding and granulating after the reaction is completed to obtain refrigerant-resistant rubber particles; S2: Inject the refrigerant-resistant rubber particles into the mold using a molding device to obtain a sealing ring blank; place the sealing ring blank in a high-pressure reactor, introduce supercritical N2, foam and mold it in an environment with a pressure of 20-28Mpa, and keep it warm for 1-2h to obtain a refrigerant-resistant sealing ring for new energy vehicle air conditioners.

[0022] Preferably, the vulcanization in step S1 includes a first vulcanization and a second vulcanization performed sequentially, wherein the first vulcanization temperature is 150-170°C, the time is 10-20 min, and the pressure is 12-15 MPa; the second vulcanization temperature is 130-150°C, the time is 30-40 min, and the pressure is 8-10 MPa.

[0023] By adopting the above technical solution, the above preparation method can evenly disperse carbon black and graphene nanosheets in the rubber matrix. After foaming, the obtained sealing ring has excellent durability and can resist failure problems caused by extreme environments. In addition, the sealing ring of the present application adopts a nitrogen foaming process to form closed micropores with a diameter of about 5μm inside the sealing ring, thereby forming a micro-nanostructure composite material, which not only reduces the overall density of the sealing ring, but also improves its thermal insulation performance.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: The sealing ring of the present application adopts nitrile rubber as matrix material, and nitrile rubber itself has good oil resistance and chemical resistance, and uses carbon black and graphene nanosheet as reinforcing filler, and carbon black and graphene nanosheet have significant synergistic enhancement effect, and at the same time, introduce thermoplastic elastomer TPE as blending and modifying component, improve the dimensional stability and resilience of sealing ring in high and low temperature cycle change. Wherein, the addition of carbon black improves the reinforcing effect of rubber, and adds a small amount of graphene nanosheet, can significantly improve the mechanical properties and medium-resistant stability of material, avoid swelling, hardening or cracking phenomenon in material, and, graphene nanosheet can reduce the material easy aging, hardening problem caused by excessive addition of carbon black. And, graphene nanosheet after the pretreatment of thionyl chloride and 3-(4-(hydroxymethyl) phenoxy) phthalonitrile, can form good interface with rubber matrix, effectively prevent the penetration of refrigerant molecules, significantly enhance the ability of sealing ring to resist the erosion of refrigerant of new energy vehicle air conditioner, ensure the sealing and reliability of air conditioning system. DETAILED DESCRIPTION

[0025] The present application is further described in detail below with reference to the embodiments.

[0026] Preparation Example Preparation Example 1 Pretreatment of graphene nanosheets: (1) adding 20 g of graphene nanosheets into 100 ml of mixed acid (prepared by mixing concentrated H2SO4:HNO3 in a volume ratio of 3:1), ultrasonically dispersing at 45°C for 3 h, washing to neutrality, and drying to obtain oxidized graphene nanosheets; (2) mixing the oxidized graphene nanosheets with 24 g of thionyl chloride, adding N,N-dimethylformamide, stirring and refluxing at 45° C. for 2 h, and distilling and recovering the thionyl chloride after the reaction to obtain chlorinated graphene nanosheets; (3) 4 g of 3-(4-(hydroxymethyl)phenoxy)phthalonitrile was dissolved in N,N-dimethylformamide, and then mixed with the chlorinated graphene nanosheets, stirred and reacted at room temperature for 3 h, washed twice, and vacuum dried to obtain pretreated graphene nanosheets.

[0027] Preparation Example 2 Pretreatment of graphene nanosheets: (1) 30 g of graphene nanosheets were added to 100 ml of mixed acid (prepared by mixing concentrated H2SO4:HNO3 in a volume ratio of 3:1), ultrasonically dispersed at 50°C for 3.5 h, washed to neutrality, and dried to obtain oxidized graphene nanosheets; (2) mixing the oxidized graphene nanosheets with 39 g of thionyl chloride, adding N,N-dimethylformamide, stirring and refluxing at 50° C. for 2.5 h, and distilling and recovering the thionyl chloride after the reaction to obtain chlorinated graphene nanosheets; (3) 5 g of 3-(4-(hydroxymethyl)phenoxy)phthalonitrile was dissolved in N,N-dimethylformamide, and then mixed with the chlorinated graphene nanosheets, stirred and reacted at room temperature for 3.5 h, washed 3 times, and vacuum dried to obtain pretreated graphene nanosheets.

[0028] Preparation Example 3 Pretreatment of graphene nanosheets: (1) adding 40 g of graphene nanosheets into 100 ml of mixed acid (prepared by mixing concentrated H2SO4:HNO3 in a volume ratio of 3:1), ultrasonically dispersing at 55°C for 4 h, washing to neutrality, and drying to obtain oxidized graphene nanosheets; (2) mixing the oxidized graphene nanosheets with 56 g of thionyl chloride, adding N,N-dimethylformamide, stirring and refluxing at 55° C. for 3 h, and distilling and recovering the thionyl chloride after the reaction to obtain chlorinated graphene nanosheets; (3) 6 g of 3-(4-(hydroxymethyl)phenoxy)phthalonitrile was dissolved in N,N-dimethylformamide, and then mixed with the chlorinated graphene nanosheets, stirred and reacted at room temperature for 4 hours, washed 3 times, and vacuum dried to obtain pretreated graphene nanosheets.

[0029] Preparation Example 4 The difference between this preparation example and preparation example 2 is that an equal amount of benzonitrile is used instead of 3-(4-(hydroxymethyl)phenoxy)phthalonitrile. Example

[0030] Example 1 A refrigerant-resistant sealing ring for an air conditioner of a new energy vehicle comprises the following raw materials: 600 g of nitrile rubber (with an acrylonitrile content of 28%), 40 g of a vulcanizing agent CZ, 60 g of a vulcanizing agent DZ, 10 g of an accelerator DM, 160 g of carbon black (MA100 from Mitsubishi, Japan), 20 g of graphene nanosheets (prepared in Preparation Example 1), 60 g of dioctyl terephthalate, 2 g of an antioxidant (bis(4-toluene yellow acid) imide), 8 g of an antioxidant RD, and 80 g of a thermoplastic elastomer TPE (PolyOne G7660-1).

[0031] The method for preparing the refrigerant-resistant sealing ring for the air conditioner of a new energy vehicle in this embodiment comprises the following steps: First, the raw materials were weighed according to the component ratio, and nitrile rubber, thermoplastic elastomer TPE, carbon black, graphene nanosheets, dioctyl terephthalate, bis(4-toluene yellow acid)imide and antioxidant RD were melt-kneaded at 145°C to obtain a premix; then, the premix was evenly mixed with vulcanizer CZ, vulcanizer DZ and accelerator DM, and the first vulcanization was carried out at 150°C and 12MPa for 10 minutes, and then the second vulcanization was carried out at 130°C and 8MPa for 30 minutes. After the reaction was completed, the refrigerant-resistant rubber particles were extruded and granulated to obtain refrigerant-resistant rubber particles; then, the refrigerant-resistant rubber particles were injected into the mold by a molding equipment to obtain a sealing ring blank; finally, the sealing ring blank was placed in a high-pressure reactor, supercritical N2 was introduced, foamed and molded in an environment with a pressure of 20Mpa, and kept warm for 1 hour to obtain a refrigerant-resistant sealing ring for new energy vehicle air conditioners.

[0032] Example 2 A refrigerant-resistant sealing ring for an air conditioner of a new energy vehicle comprises the following raw materials: 650g of nitrile rubber (with an acrylonitrile content of 30%), 30g of a vulcanizing agent CZ, 70g of a vulcanizing agent DZ, 20g of an accelerator DM, 170g of carbon black (Japan's Mitsubishi MA100), 30g of graphene nanosheets (prepared in Preparation Example 2), 80g of dioctyl terephthalate, 3g of an antioxidant (bis(4-toluene yellow acid) imide), 9g of an antioxidant RD, and 100g of a thermoplastic elastomer TPE (PolyOne G7660-1).

[0033] The method for preparing the refrigerant-resistant sealing ring for the air conditioner of a new energy vehicle in this embodiment comprises the following steps: First, the raw materials were weighed according to the component ratio, and nitrile rubber, thermoplastic elastomer TPE, carbon black, graphene nanosheets, dioctyl terephthalate, bis(4-toluene yellow acid)imide and antioxidant RD were melt-kneaded at 150°C to obtain a premix; then, the premix was evenly mixed with vulcanizer CZ, vulcanizer DZ and accelerator DM, and the first vulcanization was carried out at 160°C and 14MPa for 15 minutes, and then the second vulcanization was carried out at 140°C and 9MPa for 35 minutes. After the reaction was completed, the refrigerant-resistant rubber particles were extruded and granulated to obtain refrigerant-resistant rubber particles; then, the refrigerant-resistant rubber particles were injected into the mold by a molding equipment to obtain a sealing ring blank; finally, the sealing ring blank was placed in a high-pressure reactor, supercritical N2 was introduced, foamed and molded in an environment with a pressure of 24Mpa, and kept warm for 1.5 hours to obtain a refrigerant-resistant sealing ring for new energy vehicle air conditioners.

[0034] Example 3 A refrigerant-resistant sealing ring for an air conditioner of a new energy vehicle comprises the following raw materials: 700 g of nitrile rubber (with an acrylonitrile content of 32%), 40 g of a vulcanizing agent CZ, 80 g of a vulcanizing agent DZ, 30 g of an accelerator DM, 180 g of carbon black (MA100 from Mitsubishi, Japan), 40 g of graphene nanosheets (prepared in Preparation Example 3), 100 g of dioctyl terephthalate, 4 g of an antioxidant (bis(4-toluene yellow acid) imide), 10 g of an antioxidant RD, and 120 g of a thermoplastic elastomer TPE (PolyOne G7660-1).

[0035] The method for preparing the refrigerant-resistant sealing ring for the air conditioner of a new energy vehicle in this embodiment comprises the following steps: First, the raw materials were weighed according to the component ratio, and nitrile rubber, thermoplastic elastomer TPE, carbon black, graphene nanosheets, dioctyl terephthalate, bis(4-toluene yellow acid)imide and antioxidant RD were melt-kneaded at 155°C to obtain a premix; then, the premix was evenly mixed with vulcanizer CZ, vulcanizer DZ and accelerator DM, and the first vulcanization was carried out at 170°C and 15MPa for 20 minutes, and then the second vulcanization was carried out at 150°C and 10MPa for 40 minutes. After the reaction was completed, the refrigerant-resistant rubber particles were extruded and granulated to obtain refrigerant-resistant rubber particles; then, the refrigerant-resistant rubber particles were injected into the mold by a molding equipment to obtain a sealing ring blank; finally, the sealing ring blank was placed in a high-pressure reactor, supercritical N2 was introduced, foamed and molded in an environment with a pressure of 28Mpa, and kept warm for 2 hours to obtain a refrigerant-resistant sealing ring for new energy vehicle air conditioners.

[0036] Example 4 The difference between this embodiment and embodiment 2 is that the acrylonitrile content in the nitrile rubber is 20%.

[0037] Comparative Example Comparative Example 1 A refrigerant-resistant sealing ring for a new energy vehicle air conditioner, which differs from Example 2 in that the graphene nanosheets are the graphene nanosheets prepared in Preparation Example 4.

[0038] Comparative Example 2 A refrigerant-resistant sealing ring for a new energy vehicle air conditioner, which differs from Example 2 in that the graphene nanosheets are graphene nanosheets that have not been pretreated.

[0039] Comparative Example 3 A refrigerant-resistant sealing ring for a new energy vehicle air conditioner, which differs from Example 2 in that an equal amount of zinc oxide is used instead of graphene nanosheets.

[0040] Comparative Example 4 A refrigerant-resistant sealing ring for a new energy vehicle air conditioner, which differs from Example 2 in that no carbon black is added.

[0041] Comparative Example 5 A refrigerant-resistant sealing ring for a new energy vehicle air conditioner, which differs from Example 2 in that no graphene nanosheets are added.

[0042] Comparative Example 6 A refrigerant-resistant sealing ring for a new energy vehicle air conditioner, which differs from Example 2 in that no carbon black and graphene nanosheets are added.

[0043] Performance testing The refrigerant-resistant sealing rings for new energy vehicle air conditioners prepared in Examples 1-4 and Comparative Examples 1-6 were subjected to compression set test, tensile strength test, elongation at break test, weather resistance test, and high and low temperature resistance test. The test results are recorded in Table 1.

[0044] Compression set: According to GB / T7759.2-2014 standard, it is expressed by testing its compression set percentage at 0℃ / 72 hours.

[0045] Tensile strength and elongation at break: The tensile strength and elongation at break were tested according to ASTM-D3574-08.

[0046] Weather resistance: According to GB T 3511-2018 and GB / T16422.2-2014, irradiate the sample for 168 hours, test and calculate the performance retention percentage of its tensile strength in %.

[0047] High and low temperature resistance test: The refrigerant-resistant sealing ring for new energy vehicle air conditioning prepared in the embodiments and comparative examples was placed in a 100°C environment for 5 hours, then placed in a -20°C environment for 5 hours, and cycled 100 times. The tensile strength performance retention percentage was tested and calculated in %.

[0048] Table 1 According to the data in Example 2 and Example 4 and Table 1, the acrylonitrile content in the nitrile rubber used in this application is 28-32%, which can maintain good low-temperature flexibility and elasticity, and can also maintain good medium tolerance. The acrylonitrile content in the nitrile rubber of Example 4 is 20%, and compared with Example 2, the medium tolerance and flexibility of the sealing ring are both reduced.

[0049] According to the data in Example 2, Comparative Example 1 and Table 1, it can be seen that the effect of pre-treating the graphene nanosheets with benzonitrile is not as good as that with 3-(4-(hydroxymethyl)phenoxy)phthalonitrile, so that the dispersion effect of the graphene nanosheets in Comparative Example 1 is not obvious. On the contrary, the graphene nanosheets in Example 2 can well react with the nitrile rubber to form a chemical bond, uniformly dispersed in the rubber matrix, and form an organic-inorganic hybrid reinforcement system, thereby playing a good reinforcing role.

[0050] According to the data in Example 2, Comparative Example 2 and Table 1, after the graphene nanosheets are pretreated with thionyl chloride and 3-(4-(hydroxymethyl)phenoxy)phthalonitrile, the graphene nanosheets are changed from a stacked state to a disordered dispersion state, so as to reduce the agglomeration of the graphene nanosheets, so that they can be evenly dispersed in the rubber matrix, reduce the voids and defects in the material, improve the density of the sealing ring, and make the sealing ring have excellent corrosion resistance to resist the erosion of the refrigerant.

[0051] According to the data in Example 2, Comparative Example 3 and Table 1, the dielectric tolerance of the sealing ring is poor when zinc oxide is filled in the nitrile rubber matrix. After the graphene nanosheets are pretreated with thionyl chloride and 3-(4-(hydroxymethyl)phenoxy)phthalonitrile, they can form a good interface with the rubber matrix, effectively preventing the penetration of refrigerant molecules, significantly enhancing the ability of the sealing ring to resist the erosion of refrigerant in the air conditioner of new energy vehicles, and ensuring the sealing and reliability of the air conditioning system.

[0052] According to the data in Example 2, Comparative Examples 4-6 and Table 1, it can be seen that carbon black and graphene nanosheets have a significant synergistic enhancement effect when used as reinforcing fillers for nitrile rubber. Among them, the addition of carbon black improves the reinforcing effect of rubber, and the addition of a small amount of graphene nanosheets can significantly improve the mechanical properties and medium resistance stability of the material, avoid swelling, hardening or cracking of the material, and the graphene nanosheets can reduce the occurrence of the problem of easy aging and hardening of the material caused by excessive addition of carbon black.

[0053] 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 refrigerant-resistant sealing ring for a new energy vehicle air conditioner, characterized in that: The invention is prepared from the following raw materials by weight: 60-70 parts of nitrile rubber, 10-15 parts of vulcanization system, 16-18 parts of carbon black, 2-4 parts of graphene nanosheets, 6-10 parts of softening plasticizer, 1-2 parts of processing aid, and 8-12 parts of thermoplastic elastomer TPE; The graphene nanosheets are graphene nanosheets pretreated with thionyl chloride and 3-(4-(hydroxymethyl)phenoxy)phthalonitrile, and the weight ratio of the graphene nanosheets, thionyl chloride and 3-(4-(hydroxymethyl)phenoxy)phthalonitrile is 1:(1.2-1.4):(0.1-0.3).

2. A refrigerant-resistant sealing ring for a new energy vehicle air conditioner according to claim 1, characterized in that: The graphene nanosheets are pretreated by the following method: (1) adding graphene nanosheets to mixed acid, dispersing them ultrasonically at 45-55°C for 3-4 hours, washing them until they are neutral, and drying them to obtain oxidized graphene nanosheets; (2) mixing the oxidized graphene nanosheets with thionyl chloride, adding a catalyst, stirring and refluxing at 45-55° C. for 2-3 hours, and distilling and recovering the thionyl chloride after the reaction to obtain chlorinated graphene nanosheets; (3) Dissolving 3-(4-(hydroxymethyl)phenoxy)phthalonitrile in a solvent, mixing with the chlorinated graphene nanosheets, stirring and reacting at room temperature for 3-4 hours, washing 2-3 times, and vacuum drying to obtain pretreated graphene nanosheets.

3. A refrigerant-resistant sealing ring for a new energy vehicle air conditioner according to claim 2, characterized in that: The graphene nanosheet has a diameter of 5-10 μm, a thickness of 10-20 nm, and a specific surface area of ​​120-150 m 2 / g.

4. A refrigerant-resistant sealing ring for a new energy vehicle air conditioner according to claim 2, characterized in that: The catalyst in step (2) and the solvent in step (3) are both DMF.

5. The refrigerant-resistant sealing ring for a new energy vehicle air conditioner according to claim 1, characterized in that: The vulcanization system includes a vulcanizing agent and an accelerator. The vulcanizing agent is obtained by mixing CZ and DZ in a weight ratio of (3-4): (4-6); and the accelerator is DM.

6. The refrigerant-resistant sealing ring for a new energy vehicle air conditioner according to claim 1, characterized in that: The softening plasticizer adopts bio-based DOTP.

7. The refrigerant-resistant sealing ring for a new energy vehicle air conditioner according to claim 1, characterized in that: The processing aid includes at least one of an antioxidant, an anti-aging agent, a curing agent, and a release agent.

8. A method for preparing a refrigerant-resistant sealing ring for a new energy vehicle air conditioner according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: weighing raw materials according to the component ratio, melt-mixing nitrile rubber, thermoplastic elastomer TPE, carbon black, graphene nanosheets, softening plasticizer and processing aid at 145-155°C to obtain a premix; then, mixing the premix with a vulcanization system, vulcanizing at 130-170°C, and extruding and granulating after the reaction is completed to obtain refrigerant-resistant rubber particles; S2: Inject the refrigerant-resistant rubber particles into the mold using a molding device to obtain a sealing ring blank; place the sealing ring blank in a high-pressure reactor, introduce supercritical N2, foam and mold it in an environment with a pressure of 20-28Mpa, and keep it warm for 1-2h to obtain a refrigerant-resistant sealing ring for new energy vehicle air conditioners.

9. The method for preparing a refrigerant-resistant sealing ring for a new energy vehicle air conditioner according to claim 8, characterized in that: The vulcanization in step S1 includes a first vulcanization and a second vulcanization performed sequentially, wherein the first vulcanization temperature is 150-170° C., the time is 10-20 min, and the pressure is 12-15 MPa; the second vulcanization temperature is 130-150° C., the time is 30-40 min, and the pressure is 8-10 MPa.

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