A compound based on dynamic disulfide bonds, a lubricant, and a preparation method and application thereof

Abstract

The present invention relates to the technical field of lubricating materials, and provides a compound based on a dynamic disulfide bond, a lubricant, and a preparation method and application thereof. The compound based on a dynamic disulfide bond provided by the present invention can achieve efficient capture of a variety of base oils through the ring-opening polymerization of disulfide bonds and the coordination effect of aluminum-carboxyl groups, and can therefore be used as a gel factor or thickener for preparing a gel lubricant or grease. The present invention uses a compound based on a dynamic disulfide bond and a base oil to prepare a lubricant, and the resulting lubricant not only has excellent tribological properties and mechanical strength, but also has good thermal stability, shear thinning and creep recovery characteristics, etc.; at the same time, the lubricant provided by the present invention exhibits excellent adaptability to mechanical forces, can effectively avoid the creep leakage of the lubricant, and has broad application prospects in the field of lubrication.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating materials, and in particular to a compound based on a dynamic disulfide bond, a lubricant, and a preparation method and application thereof. Background Art

[0002] Lubricating materials with excellent synthetic properties are of great significance to improving equipment life and avoiding sudden equipment failure due to material wear.

[0003] Supramolecular gel lubricants have excellent thixotropic properties. They quickly turn into liquid phase when thixotropic or heated by external force, and quickly form gel state when stationary or cooled. They have great potential application value in mechanical sealing and lubrication. Supramolecular gel lubricants also show certain adaptability: under the action of shear force, non-covalent bonds are destroyed and the lubricant turns into sol state; when the shear force is removed, it reassembles and returns to the initial gel state.

[0004] However, current supramolecular gel lubricants are usually physical gels cross-linked by non-covalent bonds. The bond energy of non-covalent bonds is relatively small, and the speed of "breaking" and "binding" is relatively slow. Therefore, the resulting lubricant has low mechanical strength and relatively weak adaptability to mechanical forces. Summary of the invention

[0005] In view of this, the present invention provides a compound based on a dynamic disulfide bond, a lubricant, and a preparation method and application thereof. The compound based on a dynamic disulfide bond provided by the present invention can be used as a gel factor or thickener to prepare a gel lubricant or a lubricating grease, and the obtained gel lubricant and lubricating grease have high mechanical strength, good mechanical adaptability, and excellent tribological properties.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A compound based on a dynamic disulfide bond has a structure shown in any one of Formula I to Formula VI:

[0008]

[0009]

[0010] In Formula II, Formula III and Formula VI, n is independently 2-7.

[0011] The present invention also provides a method for preparing the compound based on dynamic disulfide bonds described in the above scheme, comprising the following steps:

[0012] When the dynamic disulfide bond-based compound has a structure shown in Formula I, the preparation method comprises the following steps: mixing thioctic acid, aluminum isopropoxide and chloroform for reaction to obtain a dynamic disulfide bond-based compound having a structure shown in Formula I; the molar ratio of thioctic acid to aluminum isopropoxide is 3 to 3.1:1;

[0013] When the compound based on the dynamic disulfide bond has a structure shown in Formula II or Formula III, the preparation method comprises the following steps: mixing a long-chain fatty acid, thioctic acid, aluminum isopropoxide and chloroform for reaction to obtain a compound based on the dynamic disulfide bond having a structure shown in Formula II or Formula III; when the compound based on the dynamic disulfide bond has a structure shown in Formula II, the molar ratio of the long-chain fatty acid, thioctic acid and aluminum isopropoxide is 2 to 2.05:1 to 1.05:1; when the compound based on the dynamic disulfide bond has a structure shown in Formula III, the molar ratio of the long-chain fatty acid, thioctic acid and aluminum isopropoxide is 1 to 1.05:2 to 2.05:1;

[0014] When the compound based on the dynamic disulfide bond has a structure shown in Formula IV or Formula V, the preparation method comprises the following steps: mixing thioctic acid, aluminum isopropoxide and chloroform for reaction, mixing the obtained reaction solution with water and continuing the reaction to obtain a compound based on the dynamic disulfide bond having a structure shown in Formula IV or Formula V; when the compound based on the dynamic disulfide bond has a structure shown in Formula IV, the molar ratio of thioctic acid to aluminum isopropoxide is 2 to 2.1:1; when the compound based on the dynamic disulfide bond has a structure shown in Formula V, the molar ratio of thioctic acid to aluminum isopropoxide is 1 to 1.05:1;

[0015] When the compound based on dynamic disulfide bonds has a structure shown in Formula VI, the preparation method comprises the following steps: mixing long-chain fatty acids, thioctic acid, aluminum isopropoxide and chloroform for reaction, mixing the obtained reaction solution with water and continuing the reaction to obtain a compound based on dynamic disulfide bonds having a structure shown in Formula VI; the molar ratio of the long-chain fatty acids, thioctic acid and aluminum isopropoxide is 1 to 1.05:1 to 1.05:1.

[0016] Preferably, the long-chain fatty acid is caprylic acid, capric acid, lauric acid, n-tetradecanoic acid, n-hexadecanoic acid or stearic acid.

[0017] Preferably, when preparing a dynamic disulfide bond-based compound having a structure shown in formula IV, the amount of water used is 15 to 30% of the mass of the aluminum isopropoxide; when preparing a dynamic disulfide bond-based compound having a structure shown in formula V, the amount of water used is 25 to 40% of the mass of the aluminum isopropoxide; when preparing a dynamic disulfide bond-based compound having a structure shown in formula VI, the amount of water used is 15 to 30% of the mass of the aluminum isopropoxide.

[0018] The present invention also provides the use of the dynamic disulfide bond-based compound described in the above scheme or the dynamic disulfide bond-based compound prepared by the preparation method described in the above scheme as a gel factor or thickener in a lubricant.

[0019] The present invention also provides a lubricant, comprising the dynamic disulfide bond-based compound described in the above scheme and a base oil; the lubricant is a gel lubricant or a grease.

[0020] Preferably, the mass fraction of the dynamic disulfide bond-based compound in the lubricant is 1 to 15%.

[0021] Preferably, the base oil is one or more of white oil, ester oil, poly-α-olefin, 500SN, A51, MVI300, 150BS and polyethylene glycol.

[0022] The present invention also provides a method for preparing the lubricant of the above scheme. When the lubricant is a gel lubricant, the preparation method comprises the following steps: heating and mixing the dynamic disulfide bond-based compound and base oil and then cooling to obtain the gel lubricant;

[0023] When the lubricant is grease, and the compound based on dynamic disulfide bonds has a structure shown in Formula I, the preparation method comprises the following steps: heating and mixing aluminum isopropoxide and base oil, mixing the mixture with thioctic acid solution for reaction, cooling the obtained product liquid and grinding it to obtain the grease; the molar ratio of thioctic acid to aluminum isopropoxide is 3 to 3.1:1;

[0024] When the lubricant is grease, and the compound based on dynamic disulfide bonds has a structure shown in formula II or formula III, the preparation method comprises the following steps: heating and mixing aluminum isopropoxide and base oil, mixing the mixture with long-chain fatty acids and thioctic acid solution for reaction, and sequentially heat-insulating, cooling and grinding the resulting product liquid to obtain the grease; when the compound based on dynamic disulfide bonds has a structure shown in formula II, the molar ratio of the long-chain fatty acids, thioctic acid and aluminum isopropoxide is 2.05:1 to 1.05:1; when the compound based on dynamic disulfide bonds has a structure shown in formula III, the molar ratio of the long-chain fatty acids, thioctic acid and aluminum isopropoxide is 1 to 1.05:2 to 2.05:1;

[0025] When the lubricant is grease, and the compound based on dynamic disulfide bonds has a structure shown in Formula IV or Formula V, the preparation method comprises the following steps: heating and mixing aluminum isopropoxide and base oil, mixing the mixture with thioctic acid solution for reaction, mixing the obtained reaction solution with water and continuing the reaction, and sequentially heat-insulating, cooling and grinding the obtained product liquid to obtain the grease; when the compound based on dynamic disulfide bonds has a structure shown in Formula IV, the molar ratio of thioctic acid to aluminum isopropoxide is 2 to 2.1:1; when the compound based on dynamic disulfide bonds has a structure shown in Formula V, the molar ratio of thioctic acid to aluminum isopropoxide is 1 to 1.05:1;

[0026] When the lubricant is grease, and the dynamic disulfide bond-based compound has a structure shown in Formula VI, the preparation method comprises the following steps: heating and mixing aluminum isopropoxide and base oil, mixing the mixture with long-chain fatty acids and thioctic acid solution for reaction, mixing the obtained reaction solution with water and continuing the reaction, and sequentially heat-insulating, cooling and grinding the obtained product solution to obtain the grease; the molar ratio of the long-chain fatty acid, thioctic acid and aluminum isopropoxide is 1 to 1.05:1 to 1.05:1.

[0027] The present invention also provides the use of the lubricant described in the above scheme or the lubricant prepared by the preparation method described in the above scheme in the field of lubrication of mechanical parts.

[0028] The present invention provides a compound based on a dynamic disulfide bond, having a structure shown in any one of Formulas I to VI. The compound based on a dynamic disulfide bond provided by the present invention can achieve efficient capture of a variety of base oils through ring-opening polymerization of disulfide bonds and coordination of aluminum-carboxyl groups, and can therefore be used as a gel factor or thickener for preparing gel lubricants or greases.

[0029] The present invention also provides a lubricant, including a compound based on a dynamic disulfide bond and a base oil. According to different preparation methods, the lubricant can be divided into a gel lubricant and a grease. The present invention uses a compound based on a dynamic disulfide bond and a base oil to prepare a lubricant. The obtained lubricant not only has excellent tribological properties and mechanical strength, but also has good thermal stability, shear thinning and creep recovery characteristics. Based on the shear thinning and creep recovery characteristics, the lubricant provided by the present invention exhibits excellent adaptability to mechanical forces, can effectively avoid the creep leakage of the lubricant, and has broad application prospects in the field of lubrication. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The modulus variation trend of gel lubricant A1 when the stress gradually increases and then decreases;

[0031] Figure 2The modulus variation trend of gel lubricant A1 when stress is alternating between high and low.

[0032] Figure 3 This is the thermal gravimetric curve of gel lubricant A1. DETAILED DESCRIPTION

[0033] The present invention provides a compound based on a dynamic disulfide bond, having a structure shown in any one of Formula I to Formula VI:

[0034]

[0035] In Formula II, Formula III and Formula VI, n is independently 2-7.

[0036] In the present invention, n is preferably 2, 3, 4, 5, 6 or 7.

[0037] The present invention also provides a method for preparing the compound based on dynamic disulfide bonds described in the above scheme. Different preparation methods are adopted according to different structural formulas, which are described in detail below.

[0038] In the present invention, when the dynamic disulfide bond-based compound has a structure as shown in Formula I, the preparation method comprises the following steps:

[0039] Thioctic acid, aluminum isopropoxide and chloroform are mixed and reacted to obtain a dynamic disulfide bond-based compound having a structure shown in formula I; the molar ratio of the thioctic acid to the aluminum isopropoxide is 3 to 3.1:1.

[0040] In the present invention, the reaction temperature is preferably 50-60° C., more preferably 52-55° C., and the reaction time is preferably 6 hours. In a specific embodiment of the present invention, lipoic acid is preferably first dissolved in chloroform, and then a chloroform solution of aluminum isopropoxide is added to the obtained lipoic acid solution, and then the reaction is carried out under stirring and heating conditions. After the reaction is completed, the present invention preferably removes the solvent from the obtained product liquid in vacuum to obtain a dynamic disulfide bond-based compound having a structure shown in Formula I.

[0041] In the present invention, when the dynamic disulfide bond-based compound has a structure shown in Formula II or Formula III, the preparation method comprises the following steps:

[0042] Long-chain fatty acids, lipoic acid, aluminum isopropoxide and chloroform are mixed for reaction to obtain a dynamic disulfide bond-based compound having a structure shown in Formula II or Formula III; when the dynamic disulfide bond-based compound has a structure shown in Formula II, the molar ratio of the long-chain fatty acid, lipoic acid and aluminum isopropoxide is 2 to 2.05:1 to 1.05:1, preferably 2:1:1; when the dynamic disulfide bond-based compound has a structure shown in Formula III, the molar ratio of the long-chain fatty acid, lipoic acid and aluminum isopropoxide is 1 to 1.05:2 to 2.05:1, preferably 1:2:1.

[0043] In the present invention, when preparing a dynamic disulfide bond-based compound having a structure shown in Formula II or Formula III, the specific operating steps, operating conditions and post-treatment methods are the same as those when preparing a dynamic disulfide bond-based compound having a structure shown in Formula I, only long-chain fatty acids are added; in a specific embodiment of the present invention, it is preferred to first dissolve the long-chain fatty acids and lipoic acid in chloroform, and then add a chloroform solution of aluminum isopropoxide to the obtained mixed solution for reaction.

[0044] In the present invention, when the dynamic disulfide bond-based compound has a structure shown in Formula IV or Formula V, the preparation method comprises the following steps:

[0045] Thioctic acid, aluminum isopropoxide and chloroform are mixed for reaction (recorded as the first reaction), and the obtained reaction solution is mixed with water and then continued to react (recorded as the second reaction) to obtain a dynamic disulfide bond-based compound having a structure shown in Formula IV or Formula V; when the dynamic disulfide bond-based compound has a structure shown in Formula IV, the molar ratio of thioctic acid to aluminum isopropoxide is 2 to 2.1:1, and more preferably is 2:1; when the dynamic disulfide bond-based compound has a structure shown in Formula V, the molar ratio of thioctic acid to aluminum isopropoxide is 1 to 1.05:1, and preferably is 1:1.

[0046] In the present invention, the temperature of the first reaction is preferably 50-60°C, more preferably 52-55°C, and the time of the first reaction is preferably 6h; the time of the second reaction is preferably 50-60°C, more preferably 52-55°C, and the time of the second reaction is preferably 1h. In the present invention, when preparing a compound based on a dynamic disulfide bond having a structure shown in Formula IV, the amount of water used is preferably 15-30% of the mass of the aluminum isopropoxide, more preferably 20-25%; when preparing a compound based on a dynamic disulfide bond having a structure shown in Formula V, the amount of water used is preferably 25-40% of the mass of the aluminum isopropoxide, more preferably 30-35%. In a specific embodiment of the present invention, it is preferred to first dissolve lipoic acid in chloroform, then add a chloroform solution of aluminum isopropoxide, and perform the first reaction under stirring and heating conditions. After the first reaction is completed, water is directly added to the obtained reaction solution, and the second reaction is continued under heating and stirring conditions; after the second reaction is completed, the present invention preferably removes the solvent from the obtained product liquid under vacuum to obtain a compound based on a dynamic disulfide bond having a structure shown in Formula IV or Formula V.

[0047] In the present invention, when the compound based on dynamic disulfide bonds has a structure shown in Formula VI, the preparation method comprises the following steps: mixing long-chain fatty acids, lipoic acid, aluminum isopropoxide and chloroform for reaction, mixing the obtained reaction solution with water and continuing the reaction to obtain a compound based on dynamic disulfide bonds having a structure shown in Formula VI; the molar ratio of the long-chain fatty acids, lipoic acid and aluminum isopropoxide is 1 to 1.05:1 to 1.05:1, preferably 1:1:1.

[0048] In the present invention, when preparing a dynamic disulfide bond-based compound having a structure shown in Formula VI, the specific operating steps, operating conditions and post-treatment methods are the same as those when preparing a dynamic disulfide bond-based compound having a structure shown in Formula I, only long-chain fatty acids are added, and the amount of water is changed; in a specific embodiment of the present invention, it is preferred to first dissolve long-chain fatty acids and lipoic acid in chloroform, then add a chloroform solution of aluminum isopropoxide, and perform a first reaction under stirring and heating conditions. After the first reaction is completed, water is directly added to the resulting reaction solution, and the second reaction is continued under heating and stirring conditions. In the present invention, when preparing a dynamic disulfide bond-based compound having a structure shown in Formula VI, the amount of water is preferably 15 to 30% of the mass of the aluminum isopropoxide, and more preferably 20 to 25%.

[0049] In the present invention, the long-chain fatty acid is preferably caprylic acid, capric acid, lauric acid, n-tetradecanoic acid, n-hexadecanoic acid or stearic acid, preferably stearic acid; details will not be given in detail later.

[0050] The present invention also provides the use of the dynamic disulfide bond-based compound described in the above scheme or the dynamic disulfide bond-based compound prepared by the preparation method described in the above scheme as a gelling factor or thickening agent in a lubricant; in the present invention, the lubricant includes a gel lubricant or a grease, and when the dynamic disulfide bond-based compound is used to prepare a gel lubricant, the dynamic disulfide bond-based compound plays the role of a gelling factor, and when the dynamic disulfide bond-based compound is used to prepare a grease, the dynamic disulfide bond-based compound plays the role of a thickening agent.

[0051] The present invention also provides a lubricant, comprising the dynamic disulfide bond-based compound described in the above scheme and a base oil; the lubricant is a gel lubricant or a grease.

[0052] In the present invention, the mass fraction of the compound based on dynamic disulfide bonds in the lubricant is preferably 1 to 15%, more preferably 3 to 12%, and the remainder is base oil.

[0053] In the present invention, the base oil is preferably one or more of white oil, ester oil, poly-α-olefin, 500SN, A51, MVI300, 150BS and polyethylene glycol (PEG); the PEG is preferably PEG200 and / or PEG400.

[0054] The present invention also provides a method for preparing the lubricant described in the above scheme. The lubricant provided by the present invention is divided into a gel lubricant and a grease. The preparation methods are described below respectively.

[0055] In the present invention, when the lubricant is a gel lubricant, the preparation method comprises the following steps: heating and mixing the dynamic disulfide bond-based compound and base oil (referred to as the first heating and mixing) and then cooling to obtain the gel lubricant.

[0056] In the present invention, the temperature of the first heating and mixing is preferably 145-165°C, more preferably 150-160°C, and the insulation time of the first heating and mixing is preferably 15-25min, more preferably 18-22min; the first heating and mixing is preferably carried out under stirring conditions; after the heating and mixing is completed, the obtained mixed liquid is naturally cooled to room temperature.

[0057] In the present invention, when the lubricant is grease, it is prepared by directly synthesizing a thickener in situ in the base oil, which is described in detail below.

[0058] In the present invention, when the lubricant is grease, and the dynamic disulfide bond-based compound has a structure shown in Formula I, the preparation method comprises the following steps:

[0059] Aluminum isopropoxide and base oil are heated and mixed (referred to as the second heating and mixing), the mixture is mixed with thioctic acid solution for reaction, and the resulting product liquid is sequentially kept warm, cooled and ground to obtain the grease; the molar ratio of thioctic acid to aluminum isopropoxide is 3 to 3.1:1, preferably 3:1.

[0060] In the present invention, the temperature of the second heating and mixing is preferably 120-130° C., and the second heating and mixing is preferably performed under stirring conditions. The present invention has no special requirements for the time of the second heating and mixing, as long as the aluminum isopropoxide can be completely dissolved.

[0061] After the aluminum isopropoxide is completely dissolved, the present invention preferably adds a thioctic acid solution to the system for reaction; the solvent of the thioctic acid solution is preferably dichloromethane or chloroform, more preferably dichloromethane; the reaction temperature is preferably 75-85° C., and the reaction time is preferably 5-15 min; the insulation temperature is preferably 130-150° C., more preferably 135-145° C., and the insulation time is preferably 5-10 min, more preferably 6-8 min; the cooling is preferably naturally cooled to room temperature; the grinding is preferably carried out using a three-roll mill, and the number of grinding times is preferably 3 times.

[0062] In the present invention, when the lubricant is grease, and the compound based on dynamic disulfide bonds has a structure shown in Formula II or Formula III, the preparation method comprises the following steps: heating and mixing aluminum isopropoxide and base oil, mixing the mixture with long-chain fatty acids and thioctic acid solution for reaction, and sequentially heat-insulating, cooling and grinding the resulting product liquid to obtain the grease; when the compound based on dynamic disulfide bonds has a structure shown in Formula II, the molar ratio of the long-chain fatty acids, thioctic acid and aluminum isopropoxide is 2 to 2.05:1 to 1.05:1, preferably 2:1:1; when the compound based on dynamic disulfide bonds has a structure shown in Formula III, the molar ratio of the long-chain fatty acids, thioctic acid and aluminum isopropoxide is 1 to 1.05:2 to 2.05:1, preferably 1:2:1.

[0063] In the present invention, when the compound based on dynamic disulfide bonds has a structure shown in Formula II or Formula III, the preparation method of the grease is basically the same as when the compound based on dynamic disulfide bonds has a structure shown in Formula I, only long-chain fatty acids are added, and other operating conditions remain unchanged; in a specific embodiment of the present invention, it is preferred that after aluminum isopropoxide is completely dissolved in the base oil, long-chain fatty acids are added to the system, and the reaction is carried out at 120-130°C for 5-15min (preferably 10min), and then the temperature of the reaction system is reduced to 85-90°C, and thioctic acid solution is added to react for 5-15min (preferably 10min), and after the reaction is completed, the reaction is kept warm, cooled and ground.

[0064] In the present invention, when the lubricant is grease, and the compound based on dynamic disulfide bonds has a structure shown in Formula IV or Formula V, the preparation method comprises the following steps: heating and mixing aluminum isopropoxide and base oil, mixing the mixture with thioctic acid solution for reaction, mixing the obtained reaction solution with water and continuing the reaction, and sequentially heat-insulating, cooling and grinding the obtained product liquid to obtain the grease; when the compound based on dynamic disulfide bonds has a structure shown in Formula IV, the molar ratio of thioctic acid to aluminum isopropoxide is 2 to 2.1:1, preferably 2:1; when the compound based on dynamic disulfide bonds has a structure shown in Formula V, the molar ratio of thioctic acid to aluminum isopropoxide is 1 to 1.05:1, preferably 1:1.

[0065] In the present invention, when the compound based on dynamic disulfide bonds has a structure shown in Formula IV or Formula V, the preparation method of the grease is the same as when the compound based on dynamic disulfide bonds has a structure shown in Formula I, except that the steps of mixing the obtained reaction solution with water and continuing the reaction are added, and the insulation time is extended, while other conditions remain unchanged; in the present invention, the temperature for continuing the reaction after adding water is preferably 75-85°C, and the reaction time is preferably 5-15min; the insulation time is preferably 10-15min, and the insulation temperature is the same as the above-mentioned scheme, which will not be repeated here. The present invention removes excess water by insulation; the amount of water used is the same as the amount of water used in the above-mentioned preparation of the compound with dynamic disulfide bonds having a structure shown in Formula IV or Formula V, which will not be repeated here.

[0066] In the present invention, when the lubricant is grease, and the dynamic disulfide bond-based compound has a structure shown in Formula VI, the preparation method comprises the following steps: heating and mixing aluminum isopropoxide and base oil, mixing the mixture with a long-chain fatty acid and a thioctic acid solution for reaction, mixing the obtained reaction solution with water and continuing the reaction, cooling the obtained product solution and grinding it to obtain the grease; the molar ratio of the long-chain fatty acid, thioctic acid and aluminum isopropoxide is 1 to 1.05:1 to 1.05:1, and more preferably 1:1:1.

[0067] In the present invention, when the compound based on dynamic disulfide bonds has a structure shown in Formula VI, the preparation method of the grease is basically the same as when the compound based on dynamic disulfide bonds has a structure shown in Formula IV or Formula V, only long-chain fatty acids are added, and other operating conditions remain unchanged; in a specific embodiment of the present invention, it is preferred that after aluminum isopropoxide is completely dissolved in the base oil, long-chain fatty acids are added to the system, and the reaction is carried out at 120-130°C for 5-15 minutes, and then the temperature of the reaction system is reduced to 85-90°C, and thioctic acid solution is added to react. After the reaction is completed, the obtained reaction solution is mixed with water and the reaction is continued, and then the obtained product liquid is kept warm, cooled and ground.

[0068] The present invention also provides the use of the lubricant described in the above scheme or the lubricant prepared by the preparation method described in the above scheme in the field of mechanical parts lubrication. The present invention has no special requirements on the type of the mechanical parts, and any common mechanical parts in the field can be used, such as wind power bearings; the present invention has no special requirements on the specific method of the application, and a method familiar to those skilled in the art can be used.

[0069] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0070] Example 1

[0071] Lipoic acid (0.01 mol) and stearic acid (0.02 mol) were dissolved in chloroform (50 mL), and a solution of aluminum isopropoxide (0.01 mol) in chloroform (50 mL) was added to the above solution, and heated to 55° C. under stirring conditions, and reacted for 6 hours. After the reaction was completed, the solvent was removed in vacuo to obtain a gel factor (having a structure shown in Formula II).

[0072] 0.5 g of gel factor and 9.5 g of base oil PAO10 were heated to 160° C., stirred and mixed for 20 min to obtain an oil solution, which was then cooled to room temperature to obtain a gel lubricant, which was recorded as A1.

[0073] Example 2

[0074] The preparation method of the gel factor is the same as that in Example 1.

[0075] Heat 0.5 g gel factor and 9.5 g base oil 500SN to 160 ° C and stir for 20 min to obtain SG 21 The oil solution was cooled to room temperature to obtain a gel lubricant, which was recorded as A2.

[0076] Example 3

[0077] Thioctic acid (0.01 mol) and stearic acid (0.01 mol) were dissolved in chloroform (50 mL), and a solution of aluminum isopropoxide (0.01 mol) in chloroform (50 mL) was added to the solution, and the mixture was heated to 55° C. under stirring and reacted for 6 h. Then, 0.4 g of water was added to the mixed solution, and the mixture was heated and stirred for 1 h. After the reaction was completed, the solvent was removed in vacuo to obtain a gel factor (having a structure shown in Formula VI).

[0078] Heat 0.5 g gel factor and 9.5 g base oil 500SN to 160 ° C and stir for 20 min to obtain SG 21 The oil solution was cooled to room temperature to obtain a supramolecular gel lubricant, which was designated as A3.

[0079] Example 4

[0080] Thioctic acid (0.03 mol) was dissolved in chloroform (50 mL), and a solution of aluminum isopropoxide (0.01 mol) in chloroform (50 mL) was added to the solution, and the mixture was heated to 55° C. under stirring and reacted for 6 hours. After the reaction was completed, the solvent was removed in vacuo to obtain a gel factor (having a structure shown in Formula I).

[0081] 0.5 g of gel factor and 9.5 g of base oil PEG400 were heated to 160° C., stirred and mixed for 20 min to obtain an oil solution, which was cooled to room temperature to obtain a supramolecular gel lubricant, which was recorded as A4.

[0082] Example 5

[0083] Thioctic acid (0.02 mol) and stearic acid (0.01 mol) were dissolved in chloroform (50 mL), and a solution of aluminum isopropoxide (0.01 mol) in chloroform (50 mL) was added to the solution, and the mixture was heated to 55° C. under stirring and reacted for 6 hours. After the reaction was completed, the solvent was removed in vacuo to obtain a gel factor (having a structure shown in Formula III).

[0084] 0.5 g of gel factor and 9.5 g of base oil PEG400 were heated to 160° C., stirred and mixed for 20 min to obtain an oil solution, and cooled to room temperature to obtain a gel lubricant, which was recorded as A5.

[0085] Example 6

[0086] Add aluminum isopropoxide (0.01 mol) and 60 g of base oil PAO10 to a 250 mL beaker and heat to 125 ° C while stirring. After the aluminum isopropoxide is completely dissolved, add stearic acid (0.02 mol) to the beaker, react for 10 minutes, and then reduce the heating temperature to 80 ° C. Dissolve lipoic acid (0.01 mol) in dichloromethane (20 mL), add the lipoic acid solution to the beaker, and react for 10 minutes. Raise the temperature to 140 ° C and keep warm for 8 minutes. Then, cool to room temperature and grind three times with a three-roll mill to obtain a grease, which is recorded as B1.

[0087] Example 7

[0088] Add aluminum isopropoxide (0.01 mol) and 60 g of base oil 500SN to a 250 mL beaker and heat to 125 ° C while stirring. After the aluminum isopropoxide is completely dissolved, add stearic acid (0.02 mol) to the beaker, react for 10 minutes, and then reduce the heating temperature to 80 ° C. Dissolve thioctic acid (0.01 mol) in dichloromethane (20 mL), add the thioctic acid solution to the beaker, and react for 10 minutes. Raise the temperature to 140 ° C and keep warm for 8 minutes. Then, cool to room temperature and grind three times with a three-roll mill to obtain a grease, which is recorded as B2.

[0089] Example 8

[0090] Add aluminum isopropoxide (0.01 mol) and 60 g of base oil PEG400 to a 250 mL beaker and heat to 125 ° C while stirring. Dissolve lipoic acid (0.02 mol) in dichloromethane (20 mL). After the aluminum isopropoxide in the beaker is completely dissolved, reduce the heating temperature to 80 ° C, and add the lipoic acid solution to the beaker. After reacting for 10 minutes, add 0.4 g of water and continue to react for 10 minutes. After the reaction is completed, heat to 140 ° C to remove excess water and keep warm for 12 minutes. Then, cool to room temperature and grind three times with a three-roll mill to obtain grease, recorded as B3.

[0091] Example 9

[0092] Add aluminum isopropoxide (0.01 mol) and 60 g of base oil PEG400 to a 250 mL beaker and heat to 125 ° C while stirring. Dissolve lipoic acid (0.01 mol) in dichloromethane (20 mL). After the aluminum isopropoxide in the beaker is completely dissolved, reduce the heating temperature to 80 ° C, and add the lipoic acid solution to the beaker. After reacting for 10 minutes, add 0.7 g of water and continue to react for 10 minutes. After the reaction is completed, heat to 140 ° C to remove excess water and keep warm for 12 minutes. Then, cool to room temperature and grind three times with a three-roll mill to obtain grease, recorded as B4.

[0093] Performance Test:

[0094] 1. Friction coefficient test

[0095] The friction and wear performance of each gel lubricant and grease was evaluated using the SRV-IV micro-vibration friction and wear tester produced by the German Optimol Grease Company, and compared with PAO10, 500SN, and PEG400. Among them, the friction pair of the SRV-IV micro-vibration friction and wear tester is a bearing steel ball and a bearing steel disk, and the test conditions are: temperature 25°C, frequency 25Hz, amplitude 1mm, load 300N, and test time 30min.

[0096] Table 1 Average friction coefficient of base oil and gel lubricants and greases obtained in Examples 1 to 9

[0097]

[0098]

[0099] It can be seen from the results in Table 1 that the gel lubricant and grease prepared by the present invention exhibit excellent lubrication performance and significantly reduce the average friction coefficient compared with pure base oil.

[0100] 2. Dropping point and cone penetration test of grease

[0101] The dropping point and cone penetration test results of the greases prepared in Examples 6 to 9 are shown in Table 2. The dropping point test method is GB / T 3498, and the working cone penetration test method is GB / T 3498-2008.

[0102] Table 3 Cone penetration and dropping point of grease B1 to B4

[0103] Sample No. <![CDATA[B1]]> <![CDATA[B2]]> <![CDATA[B3]]> <![CDATA[B4]]> Dropping point(℃) 141 139 161 155 Working cone penetration (0.1mm) 225 219 308 313

[0104] It can be seen from the data in Table 2 that the grease provided by the present invention has high high temperature resistance and high consistency, and can meet the use requirements.

[0105] 3. Mechanical adaptability test

[0106] The mechanical adaptability of the lubricant gel A1 prepared in Example 1 was evaluated using a HAAKE MARS RS6000 rheometer.

[0107] The modulus change of the gel lubricant A1 during stress scanning was tested, where the stress gradually increased from 1Pa to high shear stress (3000Pa) and then gradually decreased to 1Pa, shear frequency: 5Hz; test temperature: 20℃; the test results are as follows Figure 1 As shown. Figure 1 It can be seen that when the shear stress is greater than the intersection point, the G′ of the gel lubricant A1 is lower than G", and it turns into a sol state. Subsequently, in the process of the shear stress gradually decreasing from high stress to 0.1Pa, both G′ and G" gradually increase, and an intersection point appears again. This shows that after the gel lubricant A1 is transformed into a sol state under high shear stress, it gradually returns to the gel state as the shear stress decreases.

[0108] Figure 2 The modulus change of the gel lubricant A1 when high and low shear stresses are alternating (shear frequency: 5 Hz; temperature: 20°C). Figure 3It can be seen that G' of gel lubricant A1 is higher than G" under low shear stress conditions, and G' is lower than G" under high shear stress conditions. This shows that when gel lubricant A1 experiences high shear stress, the gel structure is destroyed and transformed into a sol state; while under low shear stress, it gradually self-assembles and returns to a gel state.

[0109] The above modulus variation trends with stress all indicate that the gel lubricant of the present invention is structurally destroyed under high shear stress, causing it to transform into a sol, and can be reassembled under low shear stress and recover to a gel state in a relatively short period of time, proving its high adaptability to shear force. At the same time, the higher storage modulus confirms its high mechanical strength.

[0110] 4. Thermal stability test

[0111] Figure 3 This is the thermal gravimetric curve of gel lubricant A1 obtained by testing with STA449F3. Its thermal decomposition starting temperature is above 200°C, which is similar to that of base oil PAO10, confirming its excellent thermal stability.

[0112] In addition, the same mechanical adaptability test and thermal stability test were performed on lubricants A2, A3, A4, A5, B1, B2, B3, and B4, and the results showed that the obtained lubricants all had excellent mechanical adaptability and thermal stability.

[0113] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A compound based on a dynamic disulfide bond, characterized in that: It has a structure shown in any one of Formula I to Formula VI: In Formula II, Formula III and Formula VI, n is independently 2-7.

2. The method for preparing the compound based on dynamic disulfide bonds according to claim 1, comprising the following steps: When the dynamic disulfide bond-based compound has a structure shown in Formula I, the preparation method comprises the following steps: mixing thioctic acid, aluminum isopropoxide and chloroform for reaction to obtain a dynamic disulfide bond-based compound having a structure shown in Formula I; the molar ratio of thioctic acid to aluminum isopropoxide is 3 to 3.1:1; When the compound based on the dynamic disulfide bond has a structure shown in Formula II or Formula III, the preparation method comprises the following steps: mixing a long-chain fatty acid, thioctic acid, aluminum isopropoxide and chloroform for reaction to obtain a compound based on the dynamic disulfide bond having a structure shown in Formula II or Formula III; when the compound based on the dynamic disulfide bond has a structure shown in Formula II, the molar ratio of the long-chain fatty acid, thioctic acid and aluminum isopropoxide is 2 to 2.05:1 to 1.05:1; when the compound based on the dynamic disulfide bond has a structure shown in Formula III, the molar ratio of the long-chain fatty acid, thioctic acid and aluminum isopropoxide is 1 to 1.05:2 to 2.05:1; When the compound based on the dynamic disulfide bond has a structure shown in Formula IV or Formula V, the preparation method comprises the following steps: mixing thioctic acid, aluminum isopropoxide and chloroform for reaction, mixing the obtained reaction solution with water and continuing the reaction to obtain a compound based on the dynamic disulfide bond having a structure shown in Formula IV or Formula V; when the compound based on the dynamic disulfide bond has a structure shown in Formula IV, the molar ratio of thioctic acid to aluminum isopropoxide is 2 to 2.1:1; when the compound based on the dynamic disulfide bond has a structure shown in Formula V, the molar ratio of thioctic acid to aluminum isopropoxide is 1 to 1.05:1; When the compound based on dynamic disulfide bonds has a structure shown in Formula VI, the preparation method comprises the following steps: mixing long-chain fatty acids, thioctic acid, aluminum isopropoxide and chloroform for reaction, mixing the obtained reaction solution with water and continuing the reaction to obtain a compound based on dynamic disulfide bonds having a structure shown in Formula VI; the molar ratio of the long-chain fatty acids, thioctic acid and aluminum isopropoxide is 1 to 1.05:1 to 1.05:

1.

3. The preparation method according to claim 2, characterized in that: The long-chain fatty acid is caprylic acid, capric acid, lauric acid, n-tetradecanoic acid, n-hexadecanoic acid or stearic acid.

4. The preparation method according to claim 2 or 3, characterized in that: When preparing a dynamic disulfide bond-based compound having a structure shown in formula IV, the amount of water used is 15 to 30% of the mass of the aluminum isopropoxide; when preparing a dynamic disulfide bond-based compound having a structure shown in formula V, the amount of water used is 25 to 40% of the mass of the aluminum isopropoxide; when preparing a dynamic disulfide bond-based compound having a structure shown in formula VI, the amount of water used is 15 to 30% of the mass of the aluminum isopropoxide.

5. Use of the dynamic disulfide bond-based compound according to claim 1 or the dynamic disulfide bond-based compound prepared by the preparation method according to any one of claims 2 to 4 as a gel factor or thickener in a lubricant.

6. A lubricant, characterized in that: It comprises the dynamic disulfide bond-based compound according to claim 1 and a base oil; the lubricant is a gel lubricant or a grease.

7. The lubricant according to claim 6, characterized in that The mass fraction of the compound based on dynamic disulfide bonds in the lubricant is 1-15%.

8. The lubricant according to claim 6, characterized in that The base oil is one or more of white oil, ester oil, poly-α-olefin, 500SN, A51, MVI300, 150BS and polyethylene glycol.

9. The method for preparing the lubricant according to any one of claims 6 to 8, characterized in that: When the lubricant is a gel lubricant, the preparation method comprises the following steps: heating and mixing the dynamic disulfide bond-based compound and base oil and then cooling to obtain the gel lubricant; When the lubricant is grease, and the compound based on dynamic disulfide bonds has a structure shown in Formula I, the preparation method comprises the following steps: heating and mixing aluminum isopropoxide and base oil, mixing the mixture with thioctic acid solution for reaction, cooling the obtained product liquid and grinding it to obtain the grease; the molar ratio of thioctic acid to aluminum isopropoxide is 3 to 3.1:1; When the lubricant is grease, and the compound based on dynamic disulfide bonds has a structure shown in formula II or formula III, the preparation method comprises the following steps: heating and mixing aluminum isopropoxide and base oil, mixing the mixture with long-chain fatty acids and thioctic acid solution for reaction, and sequentially heat-insulating, cooling and grinding the resulting product liquid to obtain the grease; when the compound based on dynamic disulfide bonds has a structure shown in formula II, the molar ratio of the long-chain fatty acids, thioctic acid and aluminum isopropoxide is 2.05:1 to 1.05:1; when the compound based on dynamic disulfide bonds has a structure shown in formula III, the molar ratio of the long-chain fatty acids, thioctic acid and aluminum isopropoxide is 1 to 1.05:2 to 2.05:1; When the lubricant is grease, and the compound based on dynamic disulfide bonds has a structure shown in Formula IV or Formula V, the preparation method comprises the following steps: heating and mixing aluminum isopropoxide and base oil, mixing the mixture with thioctic acid solution for reaction, mixing the obtained reaction solution with water and continuing the reaction, and sequentially heat-insulating, cooling and grinding the obtained product liquid to obtain the grease; when the compound based on dynamic disulfide bonds has a structure shown in Formula IV, the molar ratio of thioctic acid to aluminum isopropoxide is 2 to 2.1:1; when the compound based on dynamic disulfide bonds has a structure shown in Formula V, the molar ratio of thioctic acid to aluminum isopropoxide is 1 to 1.05:1; When the lubricant is grease, and the dynamic disulfide bond-based compound has a structure shown in Formula VI, the preparation method comprises the following steps: heating and mixing aluminum isopropoxide and base oil, mixing the mixture with long-chain fatty acids and thioctic acid solution for reaction, mixing the obtained reaction solution with water and continuing the reaction, and sequentially heat-insulating, cooling and grinding the obtained product solution to obtain the grease; the molar ratio of the long-chain fatty acid, thioctic acid and aluminum isopropoxide is 1 to 1.05:1 to 1.05:

1.

10. Use of the lubricant according to any one of claims 6 to 8 or the lubricant prepared by the preparation method according to claim 9 in the field of lubrication of mechanical parts.

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