Low-pressure-change sealing ring applied to new energy air conditioner and preparation method of low-pressure-change sealing ring

Abstract

The invention relates to the field of fluororubber sealing materials, and discloses a low-pressure-change sealing ring applied to a new energy air conditioner and a preparation method of the low-pressure-change sealing ring. The low-pressure-change sealing ring applied to the new energy air conditioner is prepared from the following raw materials in parts by weight: 50-60 parts of pretreated fluororubber, 30-40 parts of EPDM rubber, 25-35 parts of filler, 5-10 parts of a plasticizer, 4-8 parts of a cross-linking agent, 3-6 parts of a vulcanizing agent and 1-3 parts of an anti-aging agent. The pretreated fluororubber is prepared by mixing fluororubber, liquid polyisoprene rubber, a vinyl dimethyl terminated dimethyl-methyl trifluoropropyl polysiloxane copolymer and allyl glycidyl ether. The sealing ring prepared by the invention is applied to a new energy automobile air conditioner, has relatively low cost and low-temperature-resistant stability, can keep relatively good low-compression deformation when being used under the condition of a long-term refrigerant, and is good in sealing stability.

Description

Technical Field

[0001] The present application relates to the field of fluororubber sealing materials, and more specifically, to a low-pressure variable sealing ring used in new energy air conditioners and a preparation method thereof. Background Art

[0002] The sealing ring of the air conditioner of new energy vehicles is one of the key components to ensure the normal operation of the air conditioning system. During the operation of the air conditioning system of new energy vehicles, the refrigerant and other fluids will generate a certain pressure during the circulation process. The sealing ring needs to be able to withstand this pressure without leakage. Therefore, the sealing ring needs to have sufficient low compression deformation capacity and mechanical properties to ensure that it can still maintain a good sealing effect under high pressure, high temperature and refrigerant environment.

[0003] In order to improve the above performance of the sealing ring, fluororubber is generally used as the main material of the sealing ring, and then compounded with fillers and other additives to prepare the sealing ring. Although fluororubber has good aging resistance in the complex environment of high temperature and high pressure, it can maintain good low compression deformation performance.

[0004] However, the overall cost of fluororubber is relatively high, and its temperature resistance is relatively low in a low-temperature refrigerant environment. The resulting sealing ring is costly and prone to deformation and cracking in a low-temperature environment, which reduces the sealing stability of the sealing ring in a refrigerant environment. Summary of the invention

[0005] In order to solve the problem that sealing rings made of fluororubber as the main material are high in cost and are prone to deformation and cracking in low temperature environments, thereby reducing the sealing stability of the sealing rings in refrigerant environments, the present application provides a low-pressure variable sealing ring for use in new energy air conditioners and a preparation method thereof.

[0006] In the first aspect, the present application provides a low-pressure variable sealing ring applied to a new energy air conditioner, which adopts the following technical solution: A low-pressure variable sealing ring used in new energy air conditioners is prepared from the following raw materials in parts by weight: Pre-treated fluororubber 50-60 parts EPDM rubber 30-40 parts Filler 25-35 parts Plasticizer 5-10 parts Crosslinking agent 4-8 parts 3-6 parts of vulcanizing agent 1-3 parts of antioxidant; The pretreated fluororubber is prepared by mixing fluororubber, liquid polyisoprene rubber, vinyl dimethyl-terminated dimethyl-methyl trifluoropropyl polysiloxane copolymer and allyl glycidyl ether.

[0007] By adopting the above technical scheme, the present application adopts pre-treated fluororubber and EPDM rubber for compounding, and the two produce good synergistic effect, so that the sealing ring can reduce the cost while giving the sealing ring excellent low temperature resistance, so that the sealing ring has a lower compression deformation rate in the cold environment of the refrigerant, and is not easy to crack, so that the sealing ring can maintain good sealing stability. Due to the low compatibility of fluororubber and EPDM rubber, by introducing liquid polyisoprene rubber, vinyl dimethyl-terminated dimethyl-methyl trifluoropropyl polysiloxane copolymer and allyl glycidyl ether into fluororubber, the obtained pre-treated fluororubber and EPDM rubber have good compatibility and dispersion uniformity, and can further undergo cross-linking reaction under the action of vulcanizing agent and cross-linking agent, so as to improve the cross-linking structure density of the sealing ring, and the whole system does not need to add additional compatibilizer, so as to improve the low compression deformation ability of the obtained sealing ring under low temperature conditions, so that the sealing ring can still maintain a good sealing effect after long-term work. The filler further reinforces the mechanical strength and wear resistance of the sealing ring. Plasticizers can improve the processing performance of various raw materials in the system and further improve the comprehensive performance of the sealing ring. The sealing ring prepared in this application is used in the air-conditioning system of new energy vehicles, has good resistance to low-temperature refrigerants, and can maintain good long-term sealing stability and reliability.

[0008] Preferably, the pretreated fluororubber is prepared from the following raw materials in parts by weight: Fluororubber 80-100 parts Liquid polyisoprene rubber 20-30 parts 8-12 parts of vinyl dimethyl-terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer Allyl glycidyl ether 5-8 parts.

[0009] Preferably, the pretreated fluororubber is prepared by the following steps: mixing fluororubber, liquid polyisoprene rubber, vinyl dimethyl-terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer and allyl glycidyl ether at a temperature of 120-130° C. for 1-2 hours to prepare the pretreated fluororubber.

[0010] By adopting the above technical scheme, the present application mixes liquid polyisoprene rubber, vinyl dimethyl-terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer and allyl glycidyl ether with fluororubber in preferably preferred amounts, pretreats the fluororubber, and adds a silane copolymer having a vinyl long-chain structure and a fluorine group on the side chain and allyl glycidyl ether having a vinyl and flexible ether segment to the fluororubber system, which can produce a good synergistic effect with the liquid polyisoprene rubber, be interwoven and dispersed in the fluororubber system, and improve the compatibility of the entire fluororubber system with EPDM rubber. Under the action of a vulcanizing agent and a cross-linking agent, the components can be uniformly mixed and fully cross-linked, thereby improving the flexibility and density of the molecular structure of the obtained sealing ring, thereby improving the low compression deformation and sealing stability of the obtained sealing ring in a low temperature environment; mixing under preferably mixing conditions can further improve the uniform mixing of the components, thereby improving the comprehensive performance of the obtained pretreated fluororubber.

[0011] Preferably, the filler is one or a combination of carbon black, calcium carbonate and talc.

[0012] By adopting the above technical solution and selecting one or a combination of carbon black, calcium carbonate and talcum powder as filler, the mechanical strength and wear resistance of the sealing ring can be significantly improved.

[0013] Preferably, the plasticizer is any one of paraffin oil, dioctyl phthalate and dioctyl terephthalate.

[0014] By adopting the above technical solution and selecting any one of paraffin oil, dioctyl phthalate and dioctyl terephthalate as a plasticizer, the flexibility and processing performance of the sealing ring can be effectively improved, making it less likely to crack in a low temperature environment, thereby enhancing the overall stability and service life of the sealing ring.

[0015] Preferably, the crosslinking agent is composed of triallyl isocyanurate and tetraallyl silane in a weight ratio of (2-3):1.

[0016] By adopting the above technical solution, using triallyl isocyanurate and tetraallyl silane in a preferred weight ratio as cross-linking agents, it can be further cross-linked with the pretreated fluororubber and EPDM system to further improve the low-temperature sealing performance of the prepared sealing ring.

[0017] Preferably, the vulcanizing agent is 2,4-di-tert-butyl cumene peroxide and / or dicumyl peroxide.

[0018] By adopting the above technical solution and using 2,4-di-tert-butyl cumyl peroxide and / or dicumyl peroxide as a vulcanizing agent, the crosslinking density and vulcanization efficiency of the sealing ring can be effectively improved, thereby enhancing the mechanical strength and low temperature resistance of the sealing ring.

[0019] Preferably, the antioxidant is one or a combination of antioxidant 445, antioxidant 4010, and antioxidant 4020.

[0020] By adopting the above technical solution, the above antioxidant has good anti-aging performance, can improve the sealing stability of the prepared sealing ring under the long-term circulation conditions of low-temperature refrigerant, and improve the service life of the sealing ring.

[0021] In a second aspect, the present application provides a method for preparing a low-pressure variable sealing ring used in a new energy air conditioner, using the following technical solution: A method for preparing a low-pressure variable sealing ring used in a new energy air conditioner comprises the following steps: S1. Mixing: Mixing the pretreated fluororubber, EPDM rubber, filler, plasticizer, crosslinking agent and antioxidant to obtain a mixed material; S2, slicing: cooling to a temperature less than 90°C, adding a vulcanizing agent to the mixed material, mixing, tableting, extruding, slicing, and obtaining a preformed sheet; S3, compression molding: the prefabricated sheet is compression molded and vulcanized, and punched to obtain a low-pressure variable sealing ring.

[0022] By adopting the above technical scheme, the preparation method of mixing, slicing and molding is used, which has good operability and can produce low-pressure variable sealing rings with relatively low cost and excellent low-temperature adaptability, which are suitable for various working conditions of new energy vehicle air-conditioning systems.

[0023] Preferably, the mixing temperature in step S1 is 130-145°C, and the vulcanization temperature in step S3 is 170-180°C.

[0024] By adopting the above technical solution, the optimal mixing temperature can effectively improve the compatibility and uniform dispersion of pre-treated fluororubber and EPDM rubber, thereby enhancing the overall mechanical properties and low compression deformation capacity of the sealing ring. The optimal vulcanization temperature can make the system fully react to form a stable network cross-linking structure, further improve the heat resistance and anti-aging performance of the sealing ring, and ensure that it can still maintain a good sealing effect under high temperature, high pressure and refrigerant environment.

[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. The composite use of pretreated fluororubber and EPDM rubber significantly improves the low-temperature resistance of the sealing ring, and is compounded with fillers, plasticizers, cross-linking agents, vulcanizers and antioxidants. The sealing ring prepared in this way still maintains excellent elasticity and mechanical strength under low-temperature conditions in a refrigerant environment, and is not easy to deform and crack after long-term use.

[0026] 2. By introducing liquid polyisoprene rubber, vinyl dimethyl-terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer and allyl glycidyl ether into fluororubber, the obtained pretreated fluororubber has good compatibility and dispersion uniformity with EPDM rubber, and can further undergo cross-linking reaction under the action of vulcanizing agent and cross-linking agent, thereby improving the density of the cross-linking structure of the sealing ring. The entire system does not require the addition of additional compatibilizers, thereby improving the low compression deformation ability of the obtained sealing ring under low temperature conditions, so that the sealing ring can still maintain a good sealing effect after working for a long time.

[0027] 3. Using triallyl isocyanurate and tetraallyl silane in a preferred weight ratio as a crosslinking agent, it can be further crosslinked with the pretreated fluororubber and EPDM system to further improve the low-temperature sealing performance of the obtained sealing ring. DETAILED DESCRIPTION

[0028] The present application is further described in detail below with reference to the embodiments.

[0029] The following are the sources and specifications of some raw materials of this application. The raw materials used in the preparation examples and embodiments of this application can be obtained from the market, including but not limited to the raw materials of the following models and manufacturers. Raw materials with equivalent performance can be used: 1. Fluororubber: Chemours, USA, FKM AL-300; 2. EPDM rubber: ARLANXEO, 10660C; 3. Liquid polyisoprene rubber: manufacturer: Langbowan, molecular weight 30,000; 4. Vinyl dimethyl terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer: Sysbo silicone, VF6960; 5. Carbon black: N550 carbon black, particle size 20-80nm; 6. Paraffin oil: Model KP6030.

[0030] Preparation example of pretreated fluororubber Preparation Example 1 Preparation Example 1 discloses a pretreated fluororubber prepared by the following steps: Using a two-roll mixer, 8 kg of fluororubber, 2 kg of liquid polyisoprene rubber, 0.8 kg of vinyl dimethyl-terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer and 0.8 kg of allyl glycidyl ether were mixed at a temperature of 120° C. for 2 hours to prepare a pretreated fluororubber.

[0031] Preparation Example 2-3 The difference between Preparation Example 2-3 and Preparation Example 1 is that the amount of raw materials used and the preparation conditions are different, see Table 1 below for details.

[0032] Table 1 Parameters of Preparation Examples 1-3 Preparation Comparative Example 1 The difference between Preparation Comparative Example 1 and Preparation Example 1 is that the liquid polyisoprene rubber is replaced by fluororubber in an equal amount, and the rest is the same as Preparation Example 1.

[0033] Preparation Comparative Example 2 The difference between Preparation Comparative Example 2 and Preparation Example 1 is that the vinyl dimethyl-terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer is replaced by an equal amount of vinyl trimethoxysilane, and the rest is the same as Preparation Example 1.

[0034] Preparation Comparative Example 3 The difference between Preparation Comparative Example 2 and Preparation Example 1 is that an equal amount of allyl glycidyl ether is replaced by polyethylene glycol 800, and the rest is the same as Preparation Example 1.

[0035] Preparation Comparative Example 4 The difference between Preparation Comparative Example 4 and Preparation Example 1 is that an equal amount of allyl glycidyl ether is replaced by a vinyl dimethyl-terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer, and the rest is the same as Preparation Example 1. Example

[0036] Example 1 Example 1 discloses a low-pressure variable sealing ring used in a new energy air conditioner, which is prepared by the following steps: S1. Mixing: Using a two-roll mixer, 5 kg of pretreated fluororubber prepared in Preparation Example 1, 4 kg of EPDM rubber, 2.5 kg of carbon black as a filler, 0.5 kg of paraffin oil as a plasticizer, 0.4 kg of triallyl isocyanurate as a cross-linking agent, and 0.1 kg of antioxidant 445 were mixed at a mixing temperature of 130° C. for 3 h to obtain a mixture; S2, slicing: cooling to 89°C, adding 0.3 kg of 2,4-di-tert-butyl peroxide isopropylbenzene as a vulcanizing agent to the mixture obtained in step S1, mixing, and tableting after mixing for 10 minutes, and slicing to obtain a preformed sheet; S3, compression molding: put the prefabricated sheet into the mold of the molding vulcanizer, close the mold for compression vulcanization molding, control the vulcanization temperature to 170°C, vulcanize for 10 minutes, take it out and use stamping equipment to punch out the scraps to obtain a low-pressure variable sealing ring.

[0037] Example 2-3 The difference between Example 2-3 and Example 1 is that the amount of raw materials used and the preparation conditions are different, see Table 2 below for details.

[0038] Table 2 Parameters of Examples 1-3 Example 4 The difference between Example 4 and Example 1 is that the cross-linking agent is different. The cross-linking agent in Example 4 is composed of triallyl isocyanurate and tetraallyl silane in a weight ratio of 2:1. The rest is the same as Example 1.

[0039] Example 5 The difference between Example 5 and Example 1 is that the cross-linking agent is different. The cross-linking agent in Example 5 is composed of triallyl isocyanurate and tetraallyl silane in a weight ratio of 3:1. The rest is the same as Example 1.

[0040] Comparative Example Comparative Examples 1-4 The difference between Comparative Examples 1-4 and Example 1 is that the sources of the pretreated fluororubber are different, see Table 3 below for details.

[0041] Table 3 Sources of pretreated fluororubbers of comparative examples 1-4 Comparative Example Pre-treated fluororubber source Comparative Example 1 Preparation Comparative Example 1 Comparative Example 2 Preparation Comparative Example 2 Comparative Example 3 Preparation Comparative Example 3 Comparative Example 4 Preparation Comparative Example 4 Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the pretreated fluororubber is replaced by fluororubber in equal amounts. The fluororubber is commercially available and has the same source as the fluororubber in Preparation Example 1. The rest is the same as Example 1.

[0042] Performance testing The performance of the sealing rings prepared in Examples 1-5 and Comparative Examples 1-5 was tested as follows: a low-pressure variable sealing ring with an inner diameter of 15 mm and a cross-sectional diameter of 1.8 mm was used as a test sample for testing.

[0043] 1. Refrigerant compression deformation test: The low-pressure transformer sealing ring was immersed in pressurized liquefied HFC-134a refrigerant for 72 hours. After being taken out, the compression deformation rate (unit: %) of the low-pressure transformer sealing ring was tested according to the test method in GB / T 7759-2015, and the test results were tested and recorded.

[0044] 2. Low temperature compression deformation test: Place the low-pressure transformer sealing ring in a refrigerator at -40°C for 72 hours. After taking it out and restoring it to 25°C, refer to the test method in GB / T7759-2015 to test the compression deformation rate (unit: %) of the low-pressure transformer sealing ring, observe whether the surface is cracked, and test and record the test results.

[0045] The following are the performance test data of the low pressure variable sealing rings of Examples 1-5 and Comparative Examples 1-5, see Table 4 below for details.

[0046] Table 4 Performance data of low pressure variable sealing rings of Examples 1-5 and Comparative Examples 1-5 Combining Examples 1-3 and Comparative Examples 1-5 and Table 4, it can be concluded that the sealing ring prepared using the pretreated fluororubber of the present application has good refrigerant low-temperature stability. In Comparative Example 5, the pretreated fluororubber is replaced with commercially available fluororubber in equal amounts, and the refrigerant resistance compression deformation rate and low-temperature compression deformation rate of the prepared sealing ring are significantly improved, and obvious cracking occurs. It may be because the compatibility of fluororubber and EPDM rubber is not good, which reduces the overall performance of the prepared sealing ring. Compared with Comparative Examples 1-4, Example 1 further optimizes the pretreated fluororubber, and uses liquid polyisoprene rubber, vinyl dimethyl-terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer and allyl glycidyl ether for compounding and mixing with fluororubber. The refrigerant resistance compression deformation rate and low-temperature compression deformation rate of the sealing ring prepared in this way are significantly reduced. In Comparative Examples 1-4, the amount or components of each component are changed, and the performance of the sealing ring prepared is reduced. This may be because the synergistic effect of liquid polyisoprene rubber, vinyl dimethyl-terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer and allyl glycidyl ether is reduced, thereby reducing the cross-linking performance of the fluororubber and EPDM rubber system, resulting in reduced performance of the sealing ring prepared, and partial cracking occurs.

[0047] Combining Examples 1-3 and Examples 4-5 and Table 4, it can be concluded that further optimizing the components and ratios of the cross-linking agent can further improve the low compression performance of the obtained sealing ring. Compared with Example 1, the refrigerant resistance compression deformation rate and low temperature compression deformation rate of the obtained sealing ring in Example 4-5 are reduced, which may be because the preferred weight ratio of triallyl isocyanurate and tetraallyl silane has a good synergistic effect, further improving the cross-linking performance of the system, so that the structural density of the obtained sealing ring is further improved.

[0048] 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 low-pressure variable sealing ring used in new energy air conditioners, characterized in that: Made from the following raw materials in parts by weight: Pre-treated fluororubber 50-60 parts EPDM rubber 30-40 parts Filler 25-35 parts Plasticizer 5-10 parts Crosslinking agent 4-8 parts 3-6 parts of vulcanizing agent 1-3 parts of antioxidant; The pretreated fluororubber is prepared by mixing fluororubber, liquid polyisoprene rubber, vinyl dimethyl-terminated dimethyl-methyl trifluoropropyl polysiloxane copolymer and allyl glycidyl ether.

2. According to claim 1, a low-pressure variable sealing ring used in a new energy air conditioner is characterized in that: The pretreated fluororubber is prepared from the following raw materials in parts by weight: Fluororubber 80-100 parts Liquid polyisoprene rubber 20-30 parts 8-12 parts of vinyl dimethyl-terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer Allyl glycidyl ether 5-8 parts.

3. A low-pressure variable sealing ring used in a new energy air conditioner according to claim 2, characterized in that: The pretreated fluororubber is prepared by the following steps: The pretreated fluororubber is prepared by mixing fluororubber, liquid polyisoprene rubber, vinyl dimethyl-terminated dimethyl-methyltrifluoropropyl polysiloxane copolymer and allyl glycidyl ether at a temperature of 120-130° C. for 1-2 hours.

4. A low-pressure variable sealing ring used in a new energy air conditioner according to claim 1, characterized in that: The filler is one or a combination of carbon black, calcium carbonate and talcum powder.

5. The low-pressure variable sealing ring used in a new energy air conditioner according to claim 1 is characterized in that: The plasticizer is any one of paraffin oil, dioctyl phthalate and dioctyl terephthalate.

6. A low-pressure variable sealing ring used in a new energy air conditioner according to claim 1, characterized in that: The crosslinking agent is composed of triallyl isocyanurate and tetraallyl silane in a weight ratio of (2-3):

1.

7. A low-pressure variable sealing ring used in a new energy air conditioner according to claim 1, characterized in that: The vulcanizing agent is 2,4-di-tert-butyl cumene peroxide and / or dicumyl peroxide.

8. The low-pressure variable sealing ring used in a new energy air conditioner according to claim 1 is characterized in that: The antioxidant is one or a combination of antioxidant 445, antioxidant 4010, and antioxidant 4020.

9. A method for preparing a low-pressure variable sealing ring used in a new energy air conditioner according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Mixing: Mixing the pretreated fluororubber, EPDM rubber, filler, plasticizer, crosslinking agent and antioxidant to obtain a mixed material; S2, slicing: cooling to a temperature less than 90°C, adding a vulcanizing agent to the mixed material, mixing, tableting, extruding, slicing, and obtaining a preformed sheet; S3, compression molding: the prefabricated sheet is compression molded and vulcanized, and punched to obtain a low-pressure variable sealing ring.

10. The method for preparing a low-pressure variable sealing ring used in a new energy air conditioner according to claim 9, characterized in that: The mixing temperature in the step S1 is 130-145°C, and the vulcanization temperature in the step S3 is 170-180°C.

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