Friction pair assembly and compressor

Abstract

The invention relates to the field of compressors, and discloses a friction pair assembly and a compressor. Friction interfaces of the friction pair assembly are filled with the refrigerating machine oil composition added with the specific ionic liquid additive. The ionic liquid additive provided by the invention contains specific anions and cations optimized and improved based on a guanidine structure, and the specific anions and the cations are synergistically applied to the refrigerating machine oil, so that excellent wear resistance and metal stability can be shown, and the ionic liquid additive is suitable for friction pairs formed by various materials and has excellent thermal stability; the ionic liquid additive has the non-volatile characteristic, almost has no vapor pressure, has the characteristics of odorlessness, non-combustibility and the like, is environment-friendly, has good oil solubility in the base oil, and is suitable for being used as an anti-wear additive of the refrigerating machine oil; formula 2.

Description

Technical Field

[0001] This application relates to the field of compressors, and more particularly to a friction pair assembly and a compressor. Background Technology

[0002] Triphenyl thiophosphate (TPPT) and triphenyl phosphate (TPP), commonly used anti-wear additives in refrigeration oils, have been added to the list of Substances of Very High Concern (SVHCs) by the European Chemicals Agency (ECHA), which means that the use of TPPT in refrigeration oils will be restricted.

[0003] Currently, commonly used anti-wear agents in refrigeration oils are tricresyl phosphate (TCP) and diphenyl tert-butylphenyl phosphate. These commonly used anti-wear agents are unstable due to their inherent properties, easily leading to a decrease in anti-wear performance. Furthermore, commonly used phosphate-based anti-wear agents have drawbacks such as toxicity and environmental unfriendliness. With the increasing speed and efficiency of refrigeration compressors, the requirements for the anti-wear performance of refrigeration oils will become increasingly stringent. In the compressor structure, the contact between the vane tip and the outer peripheral surface of the roller is boundary lubrication, which is highly susceptible to wear. To address this, some have proposed coating the friction pair surfaces to improve wear resistance, or using ceramics or engineering plastics with better tribological properties as materials for the vanes and rollers. However, currently used refrigeration oils and their additive systems are developed based on metal systems and have not been optimized for other friction systems.

[0004] Therefore, it is necessary to develop environmentally friendly, highly lubricating anti-wear additives for refrigeration oils, making them suitable for friction pair components made of various materials. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a friction pair assembly that has excellent wear resistance and is suitable for friction pair assemblies made of various materials; Another object of this application is to provide a compressor based on the friction pair assembly described in this application.

[0006] To achieve all or part of the above objectives, as a first aspect of this application, a friction pair assembly is provided, including a first friction member and a second friction member, wherein the first friction member includes a first friction surface, the second friction member includes a second friction surface, and the first friction surface and the second friction surface are relatively slidingly disposed. The friction interface between the first friction surface and the second friction surface is filled with a refrigeration oil composition, the refrigeration oil composition comprising a base oil and an ionic liquid additive, the ionic liquid additive comprising a compound of the general formula shown in Formula 1; [TMG + ][X - Formula 1 Among them, the [TMG]+ The structural formula is shown in Equation 2:

[0007] Formula 2 R1 and R2 are each independently selected from C1 to C2. 10 Alkyl groups; The [X] - [Indicates selected from BF4] - PF6 - CF3SO3 - (CF3SO2)2N - (CF3SO2)3C - SnCl3 - SbF6 - AsF6 - C4F9SO3 - CF3COO - ArSO3 - One or more anions.

[0008] Optionally, R1 and R2 are each independently selected from C4 to C8 alkyl groups.

[0009] Further optionally, R1 and R2 are the same alkyl group.

[0010] Optionally, the [TMG] + It contains any one or more of the following structural formulas:

[0011] Equation 2-1

[0012] Equation 2-2

[0013] Equation 2-3

[0014] Equation 2-4.

[0015] Optionally, the ionic liquid additive includes N,N,N',N'-tetramethyl-N''-N''-dibutylguanidine tetrafluoroborate, N,N,N',N'-tetramethyl-N''-N''-dibutylguanidine hexafluorophosphate, N,N,N',N'-tetramethyl-N''-N''-dihexylguanidine tetrafluoroborate, N,N,N',N'-tetramethyl-N''-N''-dihexylguanidine hexafluorophosphate, and N,N,N',N'-tetramethyl-N''-N''-dioctylguanidine tetrafluoroborate. One or more of the following: acid salt, N,N,N',N'-tetramethyl-N''-N''-dioctylguanidine hexafluorophosphate, N,N,N',N'-tetramethyl-N''-N''-dibutylguanidine trifluoromethyl sulfate, N,N,N',N'-tetramethyl-N''-N''-dihexylguanidine stannous chloride, N,N,N',N'-tetramethyl-N''-N''-dioctylguanidine argon sulfite, and N,N,N',N'-tetramethyl-N''-N''-ditert-butylguanidine tetrafluorophosphate.

[0016] Optionally, the materials of the first friction element and the second friction element are independently selected from one or more of metals, ceramics, and engineering plastics. Further optionally, the metal is selected from one or more of steel, copper, cast iron, and alloys; the ceramic is selected from Si3N4, ZrO2, Al2O3, or ceramic composites based on any combination thereof; and the engineering plastic is selected from one or more of polyetheretherketone, polytetrafluoroethylene, polyimide, polyamide-imide, polyphenylene sulfide, and glass fiber / carbon fiber reinforced engineering plastics.

[0017] Optionally, the first friction surface of the first friction element and / or the second friction surface of the second friction element are provided with a coating film; the coating film is selected from inorganic coating film, organic coating film or composite coating film; The organic coating is selected from one or more of polytetrafluoroethylene coating, polyimide coating, polyamide-imide coating, and polyetheretherketone coating; the inorganic coating is selected from one or more of graphite film, diamond-like carbon film, chromium film, nickel film, molybdenum film, phosphorus film, and sulfur film; the composite coating is selected from one or more of polytetrafluoroethylene + graphite composite coating, polyetheretherketone + carbon fiber composite coating, and polytetrafluoroethylene + polyetheretherketone composite coating.

[0018] Optionally, the refrigeration oil composition includes a base oil, an ionic liquid additive in a content of 0.1-5%, and any one or more components selected from the following: Metal deactivators, antioxidants, anti-wear additives, acid scavengers, and antifoaming agents.

[0019] As a second aspect of this application, a compressor is provided, including the friction pair assembly described in this application.

[0020] This application describes a refrigeration oil composition containing a specific ionic liquid additive at the friction interface of a friction pair component. This ionic liquid additive comprises a specific anion and a cation optimized based on a guanidine structure. The synergistic effect of these two additives in refrigeration oil results in excellent anti-wear performance and metal stability. It is suitable for friction pairs formed from various materials and exhibits excellent thermal stability. Furthermore, the ionic liquid additive described in this application is non-volatile, has almost no vapor pressure, and is odorless, non-flammable, and environmentally friendly. It also has good oil solubility in the base oil, making it suitable as an anti-wear additive for refrigeration oil. Detailed Implementation

[0021] This application discloses a friction pair assembly and a compressor. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired result. It is particularly important to note that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this application. The products and processes described in this application have been described through preferred embodiments. Those skilled in the art can obviously modify or appropriately change and combine the products and processes described herein without departing from the content, spirit, and scope of this application to realize and apply the technology of this application. Obviously, the described embodiments are only some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application.

[0022] It should be noted that, in this document, relational terms such as "first" and "second," "step 1" and "step 2," and "(1)" and "(2)" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Moreover, the embodiments and features described in this application can be combined with each other without conflict.

[0023] Ionic liquids are organic salts that are liquid at room temperature, composed of organic cations and inorganic or organic anions. As a novel type of polar solvent, ionic liquids possess virtually no vapor pressure, are non-flammable, non-volatile, exhibit excellent chemical and thermal stability, are recyclable, and environmentally friendly; therefore, they are considered "green" chemical solvents and can be used to replace traditional volatile and toxic solvents. The properties of ionic liquids can be altered by selecting different anions, cations, and side-chain substituents.

[0024] Existing commonly used refrigeration oils and their additive systems are environmentally unfriendly and are generally based on metal systems, lacking optimization for other friction pairs. Consequently, they cannot fully exert their anti-wear and friction-reducing effects in other friction pairs. To address these shortcomings, in the first aspect of this application, a friction pair assembly is provided, including a first friction element and a second friction element. The first friction element includes a first friction surface, and the second friction element includes a second friction surface, wherein the first friction surface and the second friction surface are configured to slide relative to each other. The friction interface between the first friction surface and the second friction surface is filled with a refrigeration oil composition, the refrigeration oil composition comprising a base oil and an ionic liquid additive, the ionic liquid additive comprising a compound of the general formula shown in Formula 1; [TMG + ][X - Formula 1 Among them, the [TMG] + The structural formula is shown in Equation 2:

[0025] Formula 2 R1 and R2 are each independently selected from C1 to C2. 10 The alkyl group has a carbon number of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or any value between two of these. The alkyl group can be a straight-chain alkyl group or a branched alkyl group, including but not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, etc. The [X] - [Indicates selected from BF4] - PF6 - CF3SO3 - (CF3SO2)2N - (CF3SO2)3C - SnCl3 - SbF6 - AsF6 - C4F9SO3 - CF3COO- ArSO3 - One or more anions. In some embodiments of this application, the [X] - [Selected from BF4] - PF6 - CF3SO3 - SnCl3 - Any one of them.

[0026] The ionic liquid additive described in this application exhibits excellent anti-wear and friction-reducing properties, especially in friction pairs containing inorganic or organic coatings, or where the friction pair materials are engineering plastics, ceramics, or similar materials. The ionic liquid additive itself carries a negative charge, which readily combines with the positively charged points of the friction pair during friction, forming a stable and structurally ordered transition state. This transition state plays a role in reducing friction and resisting wear during friction, and it can form in various friction pairs such as steel / steel, steel / copper, steel / ceramic, and ceramic / ceramic.

[0027] Meanwhile, the ionic liquid additive of this application possesses excellent thermal stability due to the conjugation of three N atoms in its cation, with positive charges distributed across the three N atoms and the central carbon. It maintains good anti-wear properties even at high temperatures. Furthermore, the ionic liquid additive described in this application is non-volatile, has virtually no vapor pressure, and is odorless and non-flammable, making it environmentally friendly. It also exhibits good oil solubility in the base oil, making it suitable as an additive for refrigeration oils.

[0028] In some embodiments of this application, R1 and R2 are each independently selected from C4-C8 alkyl groups, and the number of carbon atoms can be 4, 5, 6, 7, 8, or any value between two of these. The alkyl group can be a straight-chain alkyl group or a branched alkyl group, including but not limited to n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, etc. In other embodiments of this application, for the convenience of the reaction, R1 and R2 are the same alkyl group.

[0029] In some embodiments of this application, the [TMG] + It contains any one or more of the following structural formulas:

[0030] Formula 2-1 (N,N,N',N'-Tetramethyl-N''-N''-Dibutylguanidine cation)

[0031] Formula 2-2 (N,N,N',N'-tetramethyl-N''-N''-dihexylguanidine cation)

[0032] Formula 2-3 (N,N,N',N'-Tetramethyl-N''-N''-Dioctylguanidine cation)

[0033] Formula 2-4 (N,N,N',N'-Tetramethyl-N''-N''-Di-tert-butylguanidine cation) In some embodiments of this application, the ionic liquid additive includes N,N,N',N'-tetramethyl-N''-N''-dibutylguanidine tetrafluoroborate, N,N,N',N'-tetramethyl-N''-N''-dibutylguanidine hexafluorophosphate, N,N,N',N'-tetramethyl-N''-N''-dihexylguanidine tetrafluoroborate, N,N,N',N'-tetramethyl-N''-N''-dihexylguanidine hexafluorophosphate, and N,N,N',N'-tetramethyl-N''-N''-dioctyl One or more of the following: guanidine tetrafluoroborate, N,N,N',N'-tetramethyl-N''-N''-dioctylguanidine hexafluorophosphate, N,N,N',N'-tetramethyl-N''-N''-dibutylguanidine trifluoromethyl sulfate, N,N,N',N'-tetramethyl-N''-N''-dihexylguanidine stannous chloride, N,N,N',N'-tetramethyl-N''-N''-dioctylguanidine argon sulfite, and N,N,N',N'-tetramethyl-N''-N''-ditert-butylguanidine tetrafluorophosphate.

[0034] In some embodiments of this application, the materials of the first friction element and the second friction element are independently selected from one or more of metal, ceramic, and engineering plastics. The first friction element and the second friction element may be made of the same material or different materials.

[0035] In other embodiments of this application, the metal is selected from one or more of steel, copper, cast iron, and alloys; wherein the alloys include, but are not limited to, Fe-based alloys, Al-based alloys, Cu-based alloys, etc.

[0036] The ceramic is selected from Si3N4, ZrO2, Al2O3, or ceramic composites based on any combination thereof; the engineering plastic is selected from polyetheretherketone, polytetrafluoroethylene, polyimide, polyamide-imide, polyphenylene sulfide, and any one or more of the above engineering plastics reinforced with glass fiber / carbon fiber.

[0037] In some embodiments of this application, the first friction member and the second friction member can be two friction members that are arbitrarily configured to form a friction pair in the compressor and are relatively slidingly arranged, for example: (1) Rollers and cylinder, more specifically the outer surface of the rollers and the inner surface of the cylinder. Driven by an eccentric shaft (or the eccentric part of the crankshaft), the rollers roll eccentrically on the inner wall of the cylinder. The volume of the working chamber formed between them changes periodically, thereby completing the intake, compression and exhaust processes.

[0038] (2) The slide and the roller, more specifically the head (tip) of the slide and the outer circle of the roller, the head of the slide is always in close contact with the outer circle surface of the roller, and slides back and forth as the roller rotates. Together they separate the intake chamber and the compression chamber.

[0039] (3) Rollers and crankshaft, more specifically the inner surface of the rollers and the outer surface of the eccentric portion of the crankshaft, with the inner bore of the rollers fitted onto the eccentric portion of the crankshaft. When the crankshaft rotates, it drives the rollers through its eccentric portion. They are usually fitted with sliding bearings. For example, upper flange bearings and lower flange bearings, which can also include friction pairs formed between bearings, between the lower end face of the rollers and the end face of the lower flange, and between the thrust face of the crankshaft and the end face of the lower flange.

[0040] (4) Sliding vane and sliding vane groove: The sliding vane performs high-speed reciprocating linear motion in a narrow groove on the cylinder or pump body. This is the most important friction pair of the sliding vane, which is very sensitive to friction, wear and lubrication.

[0041] In some embodiments of this application, the first friction surface of the first friction member and / or the second friction surface of the second friction member are provided with a coating film; the coating film is selected from inorganic coating film, organic coating film or composite coating film; In other embodiments of this application, the organic coating film is selected from one or more of polytetrafluoroethylene coating film, polyimide coating film, polyamide-imide coating film, and polyetheretherketone coating film; The inorganic coating is selected from one or more of graphite film, diamond-like carbon film, chromium film, nickel film, molybdenum film, phosphorus film, and sulfur film; the inorganic coating can be formed by physical vapor deposition (PVD), chemical vapor deposition (CVD), thermal spraying, or electroplating. The composite coating is selected from one or more of the following: polytetrafluoroethylene + graphite composite coating, polyetheretherketone + carbon fiber composite coating, and polytetrafluoroethylene + polyetheretherketone composite coating.

[0042] In some embodiments of this application, a method for preparing the ionic liquid additive of this application is provided, including: Using tetramethylguanidine and haloalkanes as reactants, the reaction is carried out under alkaline and phase transfer catalyst conditions to generate N,N,N',N'-tetramethyl-N''-N''-dialkyl halide. The product is then subjected to a metathesis reaction with an anionic inorganic salt to obtain the ionic liquid additive. The haloalkane includes C1~C12. 10One or more of the haloalkanes, the specific haloalkanes to be selected can refer to the selection of substituents for the cations in the ionic liquid additives; the anion includes BF4. - PF6 - CF3SO3 - (CF3SO2)2N - (CF3SO2)3C - SnCl3 - SbF6 - AsF6 - C4F9SO3 - CF3COO - ArSO3 - One or more of the following can be selected: the specific anion selection can be referenced in the selection of anions in ionic liquid additives.

[0043] In some embodiments of this application, the base includes potassium carbonate, the phase transfer catalyst includes tetrabutylammonium bromide, and the molar ratio of the tetramethylguanidine to the haloalkane is 1:1 to 5, for example 1:1, 1:2, 1:3, 1:4, 1:5 or any ratio between the two.

[0044] In some embodiments of this application, the haloalkane includes bromoalkane, such as n-butane bromo, n-hexane bromo, n-octane bromo, tert-butyl bromide, etc., and the anionic inorganic salt includes anionic sodium salt, such as sodium hexafluorophosphate, sodium tetrafluoroborate, sodium trifluoromethyl sulfate, sodium stannous chloride, etc.

[0045] In some embodiments of this application, the refrigeration oil composition includes a base oil, an ionic liquid additive in an amount of 0.1 to 5%, and any one or more components selected from the following: Metal deactivators, antioxidants, anti-wear additives, acid scavengers, and antifoaming agents.

[0046] The ionic liquid additive is selected from one or more of the ionic liquid additives described in this application. When using multiple ionic liquid additives, the proportion between them is not limited. The amount of the ionic liquid additive is 0.1% to 5%, for example, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any value between any two. Wherein, if the amount of the ionic liquid additive added is less than 0.1%, the lubricating performance of the refrigeration oil will not be significantly improved; when the amount added is greater than 5%, the lubricity commensurate with the amount added cannot be obtained, and the metal stability will decrease.

[0047] In some embodiments of this application, the base oil comprises one or more selected from polyalkylene glycols, polyvinyl ethers, polyol esters, and mineral oils. The amount of base oil used is based on the total amount of refrigeration oil and is optionally 90 wt% or more, more preferably 95 wt% or more. In other embodiments of this application, the kinematic viscosity of the base oil at 40°C is preferably 5 to 150 mmHg. 2 The viscosity index is preferably 70 or higher; the pour point is preferably below -10℃, more preferably below -20℃; and the flash point is preferably above 180℃, more preferably above 200℃. Base oils with these parameters exhibit moderate working viscosity (viscosity, viscosity index), good low-temperature fluidity (pour point), and good high-temperature stability (flash point), making them preferred choices for refrigeration oils.

[0048] The polyol ester is formed by esterification of a polyol with an organic acid. The polyol is selected from one or more of pentaerythritol, dipentaerythritol, neopentyl glycol, trimethylolpropane, and trimethylolethane. The organic acid is selected from one or more of C5-C9 straight-chain or branched, saturated or unsaturated fatty acids, more preferably a mixture of C5, C8, and C9 straight-chain or branched fatty acids. Further, the fatty acid is selected from n-valeric acid, 2-ethylpropionic acid, 2-methylbutyric acid, 3-methylbutyric acid, n-octanoic acid, 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, and 5-methylheptanoic acid. One or more of the following: acid, 5-methylheptanoic acid, 2-ethylhexanoic acid, 3-ethylhexanoic acid, 4-ethylhexanoic acid, 5-ethylhexanoic acid, n-nonanoic acid, 2-methyloctanoic acid, 3-methyloctanoic acid, 4-methyloctanoic acid, 5-methyloctanoic acid, 6-methyloctanoic acid, 7-methyloctanoic acid, 2-ethylheptanoic acid, 3-ethylheptanoic acid, 4-ethylheptanoic acid, 5-ethylheptanoic acid, 3,5,5-trimethylhexanoic acid, 3,4,5-trimethylhexanoic acid, 2-ethyl-3-methylhexanoic acid, 2-ethyl-4-methylhexanoic acid, and 2-ethyl-5-methylhexanoic acid.

[0049] The polyethylene ether is preferably a polymer having one or more structural units as shown in Formula 3 below:

[0050] Formula 3 In Equation 3, R 1b R 2b and R 3b Each can independently represent a hydrocarbon group with 1 to 8 hydrogen or carbon atoms, for example, a value with 1, 2, 3, 4, 5, 6, 7, 8 hydrogen or carbon atoms, or any value between both. R 4b R represents a divalent hydrocarbon group with 2 to 10 carbon atoms, for example, a carbon number of 2, 3, 4, 5, 6, 7, 8, 9, 10, or any value between these two. 5bThis represents a hydrocarbon group with 1 to 10 carbon atoms, for example, a carbon number of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or any value between these two ranges. r represents OR. 4b The number of repeating units represents an integer from 0 to 10, preferably an integer from 0 to 5, more preferably an integer from 0 to 3, and even more preferably 0. It should be noted that multiple ORs exist in the structural unit shown in the above general formula 3. 4b In the case of multiple ORs 4b They can be the same or different.

[0051] The polyalkylene glycol is preferably a polymer having one or more structural units as shown in Formula 4 below: R 1c -[(OR 2c )f-OR 3c g-type 4 In Equation 4, R 1c R represents a residue of a compound having 1 to 10 hydrogen atoms, an alkyl group having 2 to 10 carbon atoms, an acyl group having 2 to 8 carbon atoms, or 2 to 8 hydroxyl groups. 2c R represents an alkylene group having 2 to 4 carbon atoms. 3c It represents an alkyl group with 1 to 10 carbon atoms or an acyl group with 2 to 10 carbon atoms, f represents an integer from 1 to 80, and g represents an integer from 1 to 8.

[0052] In the above general formula 4, R 1c R 3c The alkyl group can be any of the following: straight-chain, branched, or cyclic. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 6. When the number of carbon atoms in the alkyl group is greater than 10, the compatibility with the working medium tends to decrease.

[0053] Additionally, by R 1c R 3c The alkyl portion of the acyl group can be linear, branched, or cyclic. The number of carbon atoms in the acyl group is preferably 2 to 10, more preferably 2 to 6. When the number of carbon atoms in the acyl group is greater than 10, the compatibility with the working medium decreases, and phase separation may sometimes occur.

[0054] In the case of R 1c R 3c When all represented groups are alkyl or acyl groups, R 1c R 3c The groups represented can be the same or different. Furthermore, when g is 2 or more, multiple groups in the same molecule can be represented by R. 1c R 3c The groups represented can be the same or different.

[0055] By R1c When the represented group is a residue of a compound having 2 to 8 hydroxyl groups, the compound can be either chain-like or cyclic.

[0056] It should be noted that in the above general formula 4, the number of carbon atoms or hydrogen atoms of each substituent and the number representing the repeating unit can be any integer or any range of two integers within their respective ranges, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or any point between any two.

[0057] The mineral oil is preferably obtained through the following process: Oil obtained by atmospheric distillation of crude oil based on alkane, intermediate base, or cycloalkane systems, or by vacuum distillation of the residual oil obtained from atmospheric distillation of crude oil, followed by solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrogenation purification, and then further purification; or Oils produced by isomerizing mineral oil-based waxes; or Oils and the like are produced by isomerizing GTLWAX (gas-to-liquid wax) manufactured using processes such as the Fischer-Tropsch process.

[0058] In some embodiments of this application, the refrigeration oil composition may be further supplemented with antioxidants to improve its antioxidant properties. The antioxidants include, but are not limited to, phenolic antioxidants and amine antioxidants. The phenolic antioxidants include, but are not limited to, 2,6-di-tert-butyl-p-cresol (DBPC) and 2,6-di-tert-butyl... Phenol, 4,4'-methylenebis(2,6-di-tert-butyl) Phenol, etc. The amine-based antioxidants include, but are not limited to, phenyl-α-naphthylamines, dialkylated diphenylamines, etc. One antioxidant may be used alone, or two or more may be used in combination.

[0059] In some embodiments of this application, the refrigeration oil composition may be further supplemented with anti-wear additives to improve stability. These anti-wear additives include, but are not limited to, triphenyl phosphate, tricresyl phosphate, and diphenyl-p-tert-butylphenyl phosphate. These anti-wear additives may be used alone or in combination of two or more.

[0060] In some embodiments of this application, the refrigeration oil composition may be further supplemented with acid scavengers to improve stability. The acid scavengers include, but are not limited to, epoxy compounds (epoxy-based acid scavengers). These epoxy compounds include, but are not limited to, glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, aryl ethylene oxide compounds, alkyl ethylene oxide compounds, alicyclic ethylene oxide compounds, epoxidized fatty acid monoesters, epoxidized vegetable oils, etc. These acid scavengers may be used alone or in combination of two or more.

[0061] In some embodiments of this application, the refrigeration oil composition may be further supplemented with metal deactivators to protect the metals in the refrigeration system from corrosion. These metal deactivators include, but are not limited to, benzotriazole and its derivatives, thiadiazole and its derivatives, and heterocyclic compounds. The benzotriazole and its derivatives include, but are not limited to, methyltriazole (TTZ), N,N'-dialkylaminomethylenetriazole, and N,N'-di(2-ethylhexyl)-methyl-1H-benzotriazole-1-methylamine; the thiadiazole and its derivatives include, but are not limited to, thiadiazole polysulfides, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercaptobenzothiazole, and sodium 2-mercaptobenzothiazole. These metal deactivators may be used alone or in combination of two or more.

[0062] In some embodiments of this application, the refrigeration oil composition may be further supplemented with an antifoaming agent to improve its antifoaming performance. The antifoaming agents include, but are not limited to, silicone-based and non-silicone-based agents. Silicone-based antifoaming agents include, but are not limited to, dimethyl silicone oil. Non-silicone-based antifoaming agents include, but are not limited to, homopolymers or copolymers of acrylates or methacrylates. These antifoaming agents may be used alone or in combination of two or more.

[0063] In some embodiments of this application, the amount of additives such as metal deactivators, antioxidants, anti-wear additives, acid scavengers, and antifoaming agents is not particularly limited, but preferably the content is less than 5 wt% based on the total amount of the refrigeration oil composition.

[0064] In the comparative experiments provided in this application, unless otherwise specified, all experimental conditions and materials remain consistent to ensure comparability. Furthermore, all materials used in this application are commercially available.

[0065] The following provides a further description of a friction pair assembly and a compressor provided in this application.

[0066] Example 1: Preparation of N,N,N',N'-Tetramethyl-N''-N''-Dibutylguanidine Tetrafluoroborate Tetramethylguanidine (40 mmol), tetrabutylammonium bromide (0.8 mmol), and n-butane bromide (120 mmol) were dissolved in 80 mL of acetonitrile, followed by the addition of potassium carbonate (40 mmol). The mixture was heated under reflux for 15 hours. After the reaction was complete, the mixture was cooled to room temperature, and 200 mL of water and 4 mL of 25% wt NaOH aqueous solution were added. The mixture was then extracted with petroleum ether and washed with water. 40 mL of saturated sodium bromide aqueous solution was added to the aqueous phase, and the mixture was extracted with dichloromethane. The dichloromethane was dried overnight. After pumping dryness, guanidine bromide (pale yellow colloidal substance) was obtained.

[0067] Dissolve 0.02 mol of guanidine bromide in 20 mL of distilled water. Add 40 mL of an aqueous solution containing 0.025 mol of sodium tetrafluoroborate dropwise while stirring. Stir at room temperature for 24 h, separate the oil layer, dissolve it in 20 mL of CH₂Cl₂, wash with distilled water, and dry the organic phase with anhydrous Na₂SO₄. Remove the solvent by rotary evaporation, and then pump at 100 °C for 6 h to obtain N,N,N',N'-tetramethyl-N''-N''-dibutylguanidine tetrafluoroborate ionic liquid additive.

[0068] The reaction formula is as follows:

[0069] 1 HNMR(CDCl3400MHz): 3.180(m, 4H), 3.006(S, 6H), 2.969(s, 6H), 1.897(m,2H), 1.598(m, 2H), 1.475(m, 4H), 0.959(t,J=14.4Hz;6H); 13 C NMR (CDCl3): 13.580, 19.798, 29.453, 40.053, 49.148.

[0070] Example 2: Preparation of N,N,N',N'-Tetramethyl-N''-N''-Dibutylguanidine hexafluorophosphate The synthesis was carried out according to the process of Example 1, except that the aqueous solution of sodium tetrafluoroborate was replaced with an aqueous solution of sodium hexafluorophosphate; 1 HNMR(CDCl3300MHz): 3.177(m, 4H), 2.972(s,6H), 2.947(s,6H), 1.661(m,2H), 1.466(m, 2H), 1.315(m, 4H), 0.960(t,J=14.7Hz;6H); 13CNMR(CDCl3): 13.562,19.504, 29.454, 39.931, 40.023, 49.222, 163.176.

[0071] Example 3: Preparation of N,N,N',N'-Tetramethyl-N''-N''-Dihexylguanidine tetrafluoroborate The synthesis was carried out according to the process of Example 1, except that n-bromobutane was replaced with n-bromohexane; 1 HNMR(CDCl3400MHz): 3.164(m, 4H), 3.013(s, 6H), 2.969(s, 6H), 1.616(s,2H),1.473(s, 2H), 1.415(m, 12H), 0.906(t, J = 12.4Hz; 6H); 13 C NMR(CDCl3): 13.915, 22.404, 26.348, 27.479, 31.312, 40.156, 49.468.

[0072] Example 4: Preparation of N,N,N',N'-Tetramethyl-N''-N''-Dihexylguanidine hexafluorophosphate The synthesis was carried out according to the process of Example 1, except that n-butane bromide was replaced with n-hexane bromide, and the aqueous solution of sodium tetrafluoroborate was replaced with the aqueous solution of sodium hexafluorophosphate. 1 HNMR(CDCl3400MHz): 3.156(s, 2H), 3.060(m, 2H), 2.983(s, 6H), 2.949(s,6H), 1.619(s, 2H), 1.457(s, 2H), 1.297(m, 12H), 0.904(t, J=13.2Hz; 6H); 13 C NMR(CDCl3): 13.558, 22.408, 26.302, 27.456, 31.293, 40.102, 49.582.

[0073] Example 5: Preparation of N,N,N',N'-Tetramethyl-N''-N''-Dioctylguanidine Tetrafluoroborate The synthesis was carried out according to the process of Example 1, except that n-butane bromide was replaced with n-octane bromide; 1HNMR(CDCl3400MHz): 3.167(m,4H), 3.005(s, 6H), 2.965(s, 6H), 1.620(s,2H), 1.459(s, 2H), 1.282(m, 20H), 0.896(t, J = 13.6Hz; 6H); 13 C NMR (CDCl3): 13.951, 22.482, 26.603, 27.424, 29.003, 29.072, 31.613, 40.099, 49.371, 163.168.

[0074] Example 6: Preparation of N,N,N',N'-Tetramethyl-N''-N''-Dioctylguanidine hexafluorophosphate The synthesis was carried out according to the process of Example 1, except that bromobutane was replaced with bromooctane and the aqueous solution of sodium tetrafluoroborate was replaced with the aqueous solution of sodium hexafluorophosphate. 1 HNMR(CDCl3300MHz): 3.147(m, 2H), 3.064(s, 2H), 2.956(s, 6H), 2.922(s,6H), 1.659 (s, 2H), 1.422 (s, 2H), 1.247(m, 20H), 0.874(t, J = 12.9Hz; 6H); 13 CNMR (CDCl3): 14.023, 22.528, 26.611, 27.447, 29.038, 29.095, 31.651, 40.004, 49.463, 163.168.

[0075] Example 7: Preparation of N,N,N',N'-Tetramethyl-N''-N''-Dibutylguanidine Trifluoromethyl Sulfate The synthesis was carried out according to the process of Example 1, except that the aqueous solution of sodium tetrafluoroborate was replaced with an aqueous solution of sodium trifluoromethyl sulfate.

[0076] Example 8: Preparation of N,N,N',N'-Tetramethyl-N''-N''-Dihexylguanidine stannous chloride salt The synthesis was carried out according to the process of Example 1, except that n-butane bromide was replaced with n-hexane bromide, and the aqueous solution of sodium tetrafluoroborate was replaced with an aqueous solution of sodium stannous chloride.

[0077] Example 9: Preparation of N,N,N',N'-Tetramethyl-N''-N''-Di-tert-butylguanidine tetrafluoroborate The synthesis was carried out according to the process of Example 1, except that bromobutane was replaced with tert-butyl bromide.

[0078] Example 10: Refrigeration Oil (1) Base oil The base oil is a polyol ester, specifically an ester synthesized from pentaerythritol and two fatty acids. Its specific composition and performance parameters are shown in Table 1.

[0079] Table 1

[0080] (2) Ionic liquid additives One or more of the ionic liquid additives synthesized in Examples 1-9, 0.1-5 wt%.

[0081] (3) Antioxidants 2,6-Di-tert-butyl-p-cresol; (4) Acid scavenger Neocarboxylic acid glycidyl ester (5) Metal deactivators N,N'-Dialkylaminomethylenetriazole Comparative Example 1: Commercially available tricresyl phosphate (TCP) Comparative Example 2: Commercially available 1-hexyl-3-methylimidazolium tetrafluoroborate (CAS#: 244193-50-8) Comparative Example 3: N,N,N',N'-Tetramethyl-N''-N''-Dibutylguanidine nitrate was prepared and synthesized according to the process in Example 1, except that the aqueous solution of sodium tetrafluoroborate was replaced with an aqueous solution of sodium nitrate.

[0082] Experimental example: (1) Thermal stability analysis Thermal stability analysis was performed on a thermogravimetric analyzer (TGA) under the following conditions: Temperature range: 40-600℃ Heating rate: 10℃ / min Nitrogen flow rate: 50 mL / min The thermal stability of a sample is evaluated by the initial decomposition temperature after the experiment; the higher the initial decomposition temperature, the better the thermal stability.

[0083] Table 2

[0084] As can be seen from Table 2 above, the initial thermal decomposition temperature of the ionic liquid additives in this application is higher than 320℃, which is higher than that of tricresyl phosphate TCP, a commonly used additive in refrigeration oil, and much higher than the operating temperature of refrigeration oil, thus exhibiting good thermal stability.

[0085] (2) Falex ring block test and metal stability test The samples from the examples and comparative examples were used as additives to compose refrigeration oil compositions, and experiments were conducted on their anti-wear properties.

[0086] 1. Falex ring block test The test was conducted according to the following standard: ASTM D2714 - Standard Test Methods for Calibration and Operation of the FALEX Ring and Block Friction Testing Machine and Wear Testing Machine. Test materials: ring specimens were made of cast iron, and block specimens were made of steel, Si3N4, PEEK, and DLC (steel with a DLC coating on the surface). Test start temperature: 25℃ Test duration: 1 hour Speed: 1000 rpm Load: 100 lbf The wear resistance is evaluated by the wear mark width (μm) of the test block sample. The smaller the wear mark width, the better the wear resistance.

[0087] 2. Experimental Results Table 3

[0088] Table 4

[0089] Table 5

[0090] As can be seen from the results in Tables 3 to 5, the refrigeration oil composition of this application (experimental groups 1-11) exhibits excellent tribological properties under different friction pairs, with significantly better anti-wear and friction reduction properties than the control group. The advantages are even more pronounced in friction pairs such as Si3N4-cast iron, PEEK-cast iron, and DLC-cast iron.

[0091] Compared with the control groups 3 and 4, the wear resistance of experimental groups 1, 2 and 3 was significantly worse than that of Example 1, indicating that the improvement in wear resistance at low content was not significant. The wear resistance of control group 4 was not significantly improved compared with experimental group 3, but was slightly lower, indicating that excessively high content could not achieve wear resistance commensurate with the expected addition amount.

[0092] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A friction pair assembly, characterized in that, It includes a first friction element and a second friction element, wherein the first friction element includes a first friction surface and the second friction element includes a second friction surface, and the first friction surface and the second friction surface are configured to slide relative to each other. The friction interface between the first friction surface and the second friction surface is filled with a refrigeration oil composition, the refrigeration oil composition comprising a base oil and an ionic liquid additive, the ionic liquid additive comprising a compound of the general formula shown in Formula 1; [TMG + ][X - Formula 1 Among them, the [TMG] + The structural formula is shown in Equation 2: Formula 2 R1 and R2 are each independently selected from C1 to C2. 10 Alkyl groups; The [X] - [Indicates selected from BF4] - PF6 - CF3SO3 - (CF3SO2)2N - (CF3SO2)3C - SnCl3 - SbF6 - AsF6 - C4F9SO3 - CF3COO - ArSO3 - One or more anions.

2. The friction pair assembly according to claim 1, characterized in that, R1 and R2 are each independently selected from C4 to C8 alkyl groups.

3. The friction pair assembly according to claim 1 or 2, characterized in that, R1 and R2 are the same alkyl group.

4. The friction pair assembly according to claim 1, characterized in that, The [TMG] + It contains any one or more of the following structural formulas: Equation 2-1 Equation 2-2 Equation 2-3 Equation 2-4.

5. The friction pair assembly according to any one of claims 1-4, characterized in that, The ionic liquid additives include N,N,N',N'-tetramethyl-N''-N''-dibutylguanidine tetrafluoroborate, N,N,N',N'-tetramethyl-N''-N''-dibutylguanidine hexafluorophosphate, N,N,N',N'-tetramethyl-N''-N''-dihexylguanidine tetrafluoroborate, N,N,N',N'-tetramethyl-N''-N''-dihexylguanidine hexafluorophosphate, and N,N,N',N'-tetramethyl-N''-N''-dioctylguanidine tetrafluoroborate. One or more of the following: N,N,N',N'-tetramethyl-N''-N''-dioctylguanidine hexafluorophosphate, N,N,N',N'-tetramethyl-N''-N''-dibutylguanidine trifluoromethyl sulfate, N,N,N',N'-tetramethyl-N''-N''-dihexylguanidine stannous chloride, N,N,N',N'-tetramethyl-N''-N''-dioctylguanidine argon sulfite, and N,N,N',N'-tetramethyl-N''-N''-ditert-butylguanidine tetrafluorophosphate.

6. The friction pair assembly according to claim 1, characterized in that, The materials of the first friction component and the second friction component are independently selected from any one or more of metal, ceramic, and engineering plastic.

7. The friction pair assembly according to claim 6, characterized in that, The metal is selected from one or more of steel, copper, cast iron, and alloys; the ceramic is selected from Si3N4, ZrO2, Al2O3, or ceramic composites based on any combination thereof; the engineering plastic is selected from one or more of polyetheretherketone, polytetrafluoroethylene, polyimide, polyamide-imide, polyphenylene sulfide, and glass fiber / carbon fiber reinforced engineering plastics.

8. The friction pair assembly according to claim 1, 6, or 7, characterized in that, The first friction surface of the first friction component and / or the second friction surface of the second friction component are provided with a coating film; the coating film is selected from inorganic coating film, organic coating film or composite coating film; The organic coating is selected from one or more of polytetrafluoroethylene coating, polyimide coating, polyamide-imide coating, and polyetheretherketone coating; the inorganic coating is selected from one or more of graphite film, diamond-like carbon film, chromium film, nickel film, molybdenum film, phosphorus film, and sulfur film; the composite coating is selected from one or more of polytetrafluoroethylene + graphite composite coating, polyetheretherketone + carbon fiber composite coating, and polytetrafluoroethylene + polyetheretherketone composite coating.

9. The friction pair assembly according to claim 1, characterized in that, The refrigeration oil composition comprises a base oil, an ionic liquid additive at a content of 0.1-5%, and any one or more components selected from the following: Metal deactivators, antioxidants, anti-wear additives, acid scavengers, and antifoaming agents.

10. A compressor, characterized in that, Includes the friction pair assembly as described in any one of claims 1-9.

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