Salt-resistant shield tail sealing grease and preparation method thereof

Abstract

This invention discloses a salt-resistant shield tail sealing grease and its preparation method. By weight, the salt-resistant shield tail sealing grease contains at least the following components: 21 parts acrylamide, 60-65 parts diallyl dimethyl ammonium chloride, 20-25 parts N,N-dimethylacrylamide, 43 parts emulsifier, and 1.6-1.7 parts [unclear - possibly referring to specific components]. In this invention, the emulsifier and diallyl dimethyl ammonium chloride are mixed to obtain solution A, and the initiator and water are mixed to obtain solution B. The diallyl dimethyl ammonium chloride monomer with double bonds is added to the system dropwise, avoiding the random polymerization of acrylamide, diallyl dimethyl ammonium chloride, and N,N-dimethylacrylamide. The above three monomers copolymerize to form a salt-resistant terpolymer. The salt-resistant shield tail sealing grease prepared from the salt-resistant terpolymer has excellent water pressure sealing performance, salt resistance, cone penetration, and pumpability.

Description

Technical Field

[0001] This invention belongs to the field of engineering technology, specifically relating to a salt-resistant shield tail sealing grease and its preparation method. Background Technology

[0002] During shield tunneling, tail sealing grease is used in the tail sealing device of the shield tunneling machine to play a role in lubrication, waterproofing, sealing and corrosion prevention. It can effectively isolate groundwater and mud and protect the tail brush. It is a key material in the shield tunneling process and directly affects the safety of construction.

[0003] Saline strata are widely distributed in my country, especially in the southwest and southeast regions where groundwater and soil have high salt content. These strata contain easily soluble salts such as gypsum, mirabilite, and chlorides. Influenced by these soluble salts, the physical and mechanical properties of the soil and rock masses change significantly with environmental factors such as groundwater, climate, and stress conditions. Correspondingly, their engineering properties exhibit strong solubility, expansibility, corrosivity, and variability. Currently, the development of shield tail sealing greases mainly focuses on improving their high-pressure resistance, high-temperature resistance, and environmental friendliness, with limited research on their salt resistance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing shield tail sealing greases, which lack salt resistance.

[0005] To achieve the above objectives, the present invention provides a salt-resistant tail shield sealing grease, which, by weight, comprises at least the following components:

[0006] Acrylamide: 21 parts;

[0007] diallyl dimethyl ammonium chloride: 60-65 parts;

[0008] N,N-Dimethylacrylamide: 20 to 25 parts;

[0009] Emulsifier: 43 parts;

[0010] Initiator: 1.6 to 1.7 parts.

[0011] Preferably, the emulsifier is selected from octadecyltrimethylammonium bromide.

[0012] Preferably, the initiator is selected from potassium persulfate.

[0013] Preferably, by weight, the salt-resistant shield tail sealing grease further comprises 50 to 75 parts of epoxidized soybean oil and 200 to 300 parts of lithium-based ester.

[0014] Preferably, by weight, the salt-resistant shield tail sealing grease further comprises 2 to 3 parts of defoamer P803, 50 to 70 parts of fine cotton, and 10 to 15 parts of guar gum.

[0015] Preferably, the length of the lint is 25mm to 35mm and the linear density is 2.12 to 1.56 dtex.

[0016] The present invention also provides a method for preparing the salt-resistant shield tail sealing grease as described above, comprising the following steps:

[0017] Step S1: Weigh 43 parts of emulsifier, 21 parts of acrylamide, and 20 to 25 parts of N,N-dimethylacrylamide, add them to a reaction vessel containing 900 parts of water, and continuously purge with nitrogen gas at room temperature before heating.

[0018] Step S2: Mix 43 parts of emulsifier, 60-65 parts of diallyl dimethyl ammonium chloride, and 50 parts of water to obtain solution A. Mix 1.6-1.7 parts of initiator and 50 parts of water to obtain solution B. Add solution A and solution B dropwise into the reaction vessel simultaneously using a peristaltic pump. After the addition is complete, continue the reaction and cool to room temperature to obtain the reaction product.

[0019] Step S3: Precipitate the reaction product obtained in step S2 with anhydrous ethanol and dry it under vacuum to obtain a salt-resistant terpolymer.

[0020] Step S4: Add 50-75 parts of epoxidized soybean oil, 200-300 parts of lithium-based ester, and 2-3 parts of defoamer P803 to a kneader. Add 40-80 parts of salt-resistant terpolymer, 50-70 parts of fine cotton, and 10-15 parts of guar gum to the kneader for kneading reaction. Mix evenly to obtain salt-resistant shield tail sealing grease.

[0021] Preferably, in step S1, nitrogen gas is continuously introduced and the temperature is raised to 70°C to 80°C.

[0022] Preferably, in step S2, the addition of solution A and solution B is completed within 40 minutes and 45 minutes, respectively.

[0023] Preferably, in step S2, the continued reaction time is 5h to 6h.

[0024] The beneficial effects of this invention are:

[0025] This invention uses acrylamide, diallyl dimethyl ammonium chloride, and N,N-dimethylacrylamide as main raw materials, and octadecyltrimethylammonium bromide as an emulsifier. Under the action of potassium persulfate initiator, a salt-resistant terpolymer is first prepared by copolymerization. The acrylamide and N,N-dimethylacrylamide are emulsified to form an emulsion using an emulsifier. Then, diallyl dimethyl ammonium chloride, a monomer with two double bonds, is added to the above system by gradually adding solution A (a mixed emulsion formed by octadecyltrimethylammonium bromide and diallyl dimethyl ammonium chloride) and solution B (an aqueous solution of the initiator). This avoids the random polymerization of the three monomers. The salt-resistant terpolymer has good thickening properties, temperature resistance, and salt resistance. The prepared salt-resistant tail sealant has better salt resistance and flame retardant properties, improving the adaptability of the tail sealant in saline geological conditions. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to the embodiments.

[0027] This invention provides a salt-resistant shield tail sealing grease, which, by weight, contains at least the following components: 21 parts acrylamide, 60-65 parts diallyl dimethyl ammonium chloride, 20-25 parts N,N-dimethylacrylamide, 43 parts octadecyltrimethylammonium bromide, 1.6-1.7 parts potassium persulfate, 50-75 parts epoxidized soybean oil, 200-300 parts lithium ester, 2-3 parts defoamer P803, 50-70 parts fine cotton, and 10-15 parts guar gum.

[0028] The preparation method of the salt-resistant shield tail sealing grease of the present invention includes the following steps:

[0029] Step S1: Weigh 43 parts of octadecyltrimethylammonium bromide, 21 parts of acrylamide, and 20 to 25 parts of N,N-dimethylacrylamide, and add them to a reaction vessel containing 900 parts of water. The reaction vessel includes a reflux condenser and a thermometer. Nitrogen gas is continuously introduced at room temperature, and then the temperature is raised to 70°C to 80°C.

[0030] Step S2: Mix 43 parts of octadecyltrimethylammonium bromide, 60-65 parts of diallyldimethylammonium chloride, and 50 parts of water to obtain solution A. Mix 1.6-1.7 parts of potassium persulfate (KPS) and 50 parts of water to obtain solution B. Add solutions A and B dropwise into the reaction vessel simultaneously using a peristaltic pump. Control the addition of solution A to be completed within 40 minutes and the addition of solution B to be completed within 45 minutes. After the addition is completed, continue the reaction for 5-6 hours, cool to room temperature, and obtain the reaction product.

[0031] Step S3: Precipitate the reaction product obtained in step S2 with anhydrous ethanol and dry it under vacuum to obtain a salt-resistant terpolymer.

[0032] Step S4: Add 50-75 parts of epoxidized soybean oil, 200-300 parts of lithium-based ester, and 2-3 parts of defoamer P803 to a kneader. Add 40-80 parts of salt-resistant terpolymer, 50-70 parts of fine cotton, and 10-15 parts of guar gum to the kneader for kneading reaction. Mix evenly to obtain salt-resistant shield tail sealing grease.

[0033] As shown in Formula I, this invention uses acrylamide, diallyl dimethyl ammonium chloride, and N,N-dimethylacrylamide as main raw materials, where x, y, and z represent the molar amounts of the three monomers, with x:y:z = 0.3:(0.37–0.4):(0.2–0.25). Using octadecyltrimethylammonium bromide as an emulsifier and potassium persulfate as an initiator, a salt-resistant terpolymer is first prepared by copolymerization. The diallyl dimethyl ammonium chloride monomer, which has double bonds, is then added to the system dropwise, avoiding random polymerization among the three monomers and controlling the amount of diallyl dimethyl ammonium chloride entering the polymer chain. Acrylamide is an aqueous monomer and a key material for synthesizing salt-resistant polymers, possessing flocculation, thickening, drag-reducing, and dispersing properties. Diallyl dimethyl ammonium chloride can enhance the rigidity of the molecular chain and the steric hindrance effect of the side groups, or change the charge and distribution of the branches, thereby increasing the hydrodynamics of the polymer in highly salinized aqueous solutions. N,N-Dimethylacrylamide readily forms polymers with high polymerization degrees, exhibiting properties such as dispersibility, desiccant, protective stability, and adhesiveness.

[0034]

[0035] Example 1

[0036] The preparation method of the salt-resistant shield tail sealing grease provided in this embodiment includes the following steps:

[0037] Step S1: Weigh 43 parts of octadecyltrimethylammonium bromide, 21 parts of acrylamide, and 20 parts of N,N-dimethylacrylamide, and add them to a reaction vessel containing 900 parts of water. The reaction vessel is equipped with a reflux condenser and a thermometer. Nitrogen gas is continuously introduced at room temperature, and then the temperature is raised to 70°C.

[0038] Step S2: Mix 43 parts of octadecyltrimethylammonium bromide, 60 parts of diallyldimethylammonium chloride, and 50 parts of water to obtain solution A. Mix 1.6 parts of potassium persulfate (KPS) and 50 parts of water to obtain solution B. Add solutions A and B dropwise into the reaction vessel simultaneously using a peristaltic pump. Control the addition of solution A to be completed within 40 minutes and the addition of solution B to be completed within 45 minutes. After the addition is completed, continue the reaction for 5 hours and cool to room temperature to obtain the reaction product.

[0039] Step S3: Precipitate the reaction product obtained in step S2 with anhydrous ethanol and dry it under vacuum to obtain a salt-resistant terpolymer.

[0040] Step S4: Add 50 parts of epoxidized soybean oil, 200 parts of lithium-based ester, and 2 parts of defoamer P803 to a kneader. Add 40 parts of salt-resistant terpolymer, 50 parts of fine cotton, and 10 parts of guar gum to the kneader for kneading reaction. Stir for 30 minutes to obtain salt-resistant shield tail sealing grease.

[0041] Example 2

[0042] The preparation method of the salt-resistant shield tail sealing grease provided in this embodiment includes the following steps:

[0043] Step S1: Weigh 43 parts of octadecyltrimethylammonium bromide, 21 parts of acrylamide, and 22.5 parts of N,N-dimethylacrylamide, and add them to a reaction vessel containing 900 parts of water. The reaction vessel includes a reflux condenser and a thermometer. Nitrogen gas is continuously introduced at room temperature, and then the temperature is raised to 70°C.

[0044] Step S2: Mix 43 parts of octadecyltrimethylammonium bromide, 63 parts of diallyldimethylammonium chloride, and 50 parts of water to obtain solution A. Mix 1.65 parts of potassium persulfate (KPS) and 50 parts of water to obtain solution B. Add solutions A and B dropwise into the reaction vessel simultaneously using a peristaltic pump. Control the addition of solution A to be completed within 40 minutes and the addition of solution B to be completed within 45 minutes. After the addition is completed, continue the reaction for 5.5 hours, cool to room temperature, and obtain the reaction product.

[0045] Step S3: Precipitate the reaction product obtained in step S2 with anhydrous ethanol and dry it under vacuum to obtain a salt-resistant terpolymer.

[0046] Step S4: Add 65 parts of epoxidized soybean oil, 250 parts of lithium-based ester, and 2.5 parts of defoamer P803 to a kneader. Add 60 parts of salt-resistant terpolymer, 60 parts of fine cotton, and 12.5 parts of guar gum to the kneader for kneading reaction. Stir for 30 minutes to obtain salt-resistant shield tail sealing grease.

[0047] Example 3

[0048] The preparation method of the salt-resistant shield tail sealing grease provided in this embodiment includes the following steps:

[0049] Step S1: Weigh 43 parts of octadecyltrimethylammonium bromide, 21 parts of acrylamide, and 25 parts of N,N-dimethylacrylamide, and add them to a reaction vessel containing 900 parts of water. The reaction vessel includes a reflux condenser and a thermometer. Nitrogen gas is continuously introduced at room temperature, and then the temperature is raised to 70°C.

[0050] Step S2: Mix 43 parts of octadecyltrimethylammonium bromide, 65 parts of diallyldimethylammonium chloride, and 50 parts of water to obtain solution A. Mix 1.7 parts of potassium persulfate (KPS) and 50 parts of water to obtain solution B. Add solutions A and B dropwise into the reaction vessel simultaneously using a peristaltic pump. Control the addition of solution A to be completed within 40 minutes and the addition of solution B to be completed within 45 minutes. After the addition is completed, continue the reaction for 6 hours and cool to room temperature to obtain the reaction product.

[0051] Step S3: Precipitate the reaction product obtained in step S2 with anhydrous ethanol and dry it under vacuum to obtain a salt-resistant terpolymer.

[0052] Step S4: Add 75 parts of epoxidized soybean oil, 300 parts of lithium-based ester, and 3 parts of defoamer P803 to a kneader. Add 80 parts of salt-resistant terpolymer, 70 parts of fine cotton, and 15 parts of guar gum to the kneader for kneading reaction. Stir for 30 minutes to obtain salt-resistant shield tail sealing grease.

[0053] Example 4

[0054] The preparation method of the salt-resistant shield tail sealing grease provided in this embodiment includes the following steps:

[0055] Step S1: Weigh 43 parts of octadecyltrimethylammonium bromide, 21 parts of acrylamide, and 22.5 parts of N,N-dimethylacrylamide, and add them to a reaction vessel containing 900 parts of water. The reaction vessel includes a reflux condenser and a thermometer. Nitrogen gas is continuously introduced at room temperature, and then the temperature is raised to 70°C.

[0056] Step S2: Mix 43 parts of octadecyltrimethylammonium bromide, 63 parts of diallyldimethylammonium chloride, and 50 parts of water to obtain solution A. Mix 1.65 parts of potassium persulfate (KPS) and 50 parts of water to obtain solution B. Add solutions A and B dropwise into the reaction vessel simultaneously using a peristaltic pump. Control the addition of solution A to be completed within 40 minutes and the addition of solution B to be completed within 45 minutes. After the addition is completed, continue the reaction for 5.5 hours, cool to room temperature, and obtain the reaction product.

[0057] Step S3: Precipitate the reaction product obtained in step S2 with anhydrous ethanol and dry it under vacuum to obtain a salt-resistant terpolymer.

[0058] Step S4: Add 50 parts of epoxidized soybean oil, 200 parts of lithium-based ester, and 2 parts of defoamer P803 to a kneader. Add 40 parts of salt-resistant terpolymer, 50 parts of fine cotton, and 10 parts of guar gum to the kneader for kneading reaction. Stir for 30 minutes to obtain salt-resistant shield tail sealing grease.

[0059] Example 5

[0060] The preparation method of the salt-resistant shield tail sealing grease provided in this embodiment includes the following steps:

[0061] Step S1: Weigh 43 parts of octadecyltrimethylammonium bromide, 21 parts of acrylamide, and 22.5 parts of N,N-dimethylacrylamide, and add them to a reaction vessel containing 900 parts of water. The reaction vessel includes a reflux condenser and a thermometer. Nitrogen gas is continuously introduced at room temperature, and then the temperature is raised to 70°C.

[0062] Step S2: Mix 43 parts of octadecyltrimethylammonium bromide, 63 parts of diallyldimethylammonium chloride, and 50 parts of water to obtain solution A. Mix 1.65 parts of potassium persulfate (KPS) and 50 parts of water to obtain solution B. Add solutions A and B dropwise into the reaction vessel simultaneously using a peristaltic pump. Control the addition of solution A to be completed within 40 minutes and the addition of solution B to be completed within 45 minutes. After the addition is completed, continue the reaction for 5.5 hours, cool to room temperature, and obtain the reaction product.

[0063] Step S3: Precipitate the reaction product obtained in step S2 with anhydrous ethanol and dry it under vacuum to obtain a salt-resistant terpolymer.

[0064] Step S4: Add 75 parts of epoxidized soybean oil, 300 parts of lithium-based ester, and 3 parts of defoamer P803 to a kneader. Add 80 parts of salt-resistant terpolymer, 70 parts of fine cotton, and 15 parts of guar gum to the kneader for kneading reaction. Stir for 30 minutes to obtain salt-resistant shield tail sealing grease.

[0065] Comparative Example 1

[0066] This comparative example is based on Example 2, but without the addition of a salt-resistant terpolymer; the remaining steps are the same as in Example 2.

[0067] Add 65 parts of epoxidized soybean oil, 250 parts of lithium-based ester, and 2.5 parts of defoamer P803 to a kneader. Add 60 parts of fine cotton and 12.5 parts of guar gum to the kneader for kneading reaction. Stir for 30 minutes to obtain salt-resistant shield tail sealing grease.

[0068] Comparative Example 2

[0069] This comparative example is based on Example 2, with the addition of salt-resistant polyacrylamide with a molecular weight of 25 million, and the remaining steps are the same as in Example 2.

[0070] Add 65 parts of epoxidized soybean oil, 250 parts of lithium-based ester, and 2.5 parts of defoamer P803 to a kneader. Add 60g of salt-resistant polyacrylamide, 60 parts of fine cotton, and 12.5 parts of guar gum to the kneader for kneading reaction. Stir for 30 minutes to obtain salt-resistant shield tail sealing grease.

[0071] Comparative Example 3

[0072] This comparative example is based on Example 2 without the addition of N,N-dimethylacrylamide.

[0073] Step S1: Weigh 43 parts of octadecyltrimethylammonium bromide and 21 parts of acrylamide, and add them to a reaction vessel containing 900 parts of water. The reaction vessel includes a reflux condenser and a thermometer. Nitrogen gas is continuously introduced at room temperature, and then the temperature is raised to 70°C.

[0074] Step S2: Mix 43 parts of octadecyltrimethylammonium bromide, 63 parts of diallyldimethylammonium chloride, and 50 parts of water to obtain solution A. Mix 1.65 parts of potassium persulfate (KPS) and 50 parts of water to obtain solution B. Add solutions A and B dropwise into the reaction vessel simultaneously using a peristaltic pump. Control the addition of solution A to be completed within 40 minutes and the addition of solution B to be completed within 45 minutes. After the addition is completed, continue the reaction for 5.5 hours, cool to room temperature, and obtain the reaction product.

[0075] Step S3: Precipitate the reaction product obtained in step S2 with anhydrous ethanol and dry it under vacuum to obtain a salt-resistant terpolymer.

[0076] Step S4: Add 75 parts of epoxidized soybean oil, 300 parts of lithium-based ester, and 3 parts of defoamer P803 to a kneader. Add 80 parts of salt-resistant terpolymer, 70 parts of fine cotton, and 15 parts of guar gum to the kneader for kneading reaction. Stir for 30 minutes to obtain salt-resistant shield tail sealing grease.

[0077] Comparative Example 4

[0078] This comparative example uses octadecyl methacrylate instead of N,N-dimethylacrylamide, based on Example 2.

[0079] Step S1: Weigh 43 parts of octadecyltrimethylammonium bromide, 21 parts of acrylamide, and 22.5 parts of octadecyl methacrylate, and add them to a reaction vessel containing 900 parts of water. The reaction vessel includes a reflux condenser and a thermometer. Nitrogen gas is continuously introduced at room temperature, and then the temperature is raised to 70°C.

[0080] Step S2: Mix 43 parts of octadecyltrimethylammonium bromide, 63 parts of diallyldimethylammonium chloride, and 50 parts of water to obtain solution A. Mix 1.65 parts of potassium persulfate (KPS) and 50 parts of water to obtain solution B. Add solutions A and B dropwise into the reaction vessel simultaneously using a peristaltic pump. Control the addition of solution A to be completed within 40 minutes and the addition of solution B to be completed within 45 minutes. After the addition is completed, continue the reaction for 5.5 hours, cool to room temperature, and obtain the reaction product.

[0081] Step S3: Precipitate the reaction product obtained in step S2 with anhydrous ethanol and dry it under vacuum to obtain a salt-resistant terpolymer.

[0082] Step S4: Add 75 parts of epoxidized soybean oil, 300 parts of lithium-based ester, and 3 parts of defoamer P803 to a kneader. Add 80 parts of salt-resistant terpolymer, 70 parts of fine cotton, and 15 parts of guar gum to the kneader for kneading reaction. Stir for 30 minutes to obtain salt-resistant shield tail sealing grease.

[0083] Comparative Example 5

[0084] This comparative example uses CONDAT (model WR89NG) shield tail sealing grease.

[0085] Comparative Example 6

[0086] This comparative example uses BASF (model MEYCO-TSG) shield tail sealing grease.

[0087] The performance of the salt-resistant shield tail sealing greases prepared in Examples 1-5 and Comparative Examples 1-6 was tested, and the test results are shown in Table 1.

[0088] Table 1 Performance Tests of Salt-Resistant Tail Sealing Grease

[0089]

[0090] Pumpability refers to whether the sealing grease has good properties such as being able to pass smoothly through the delivery pipeline without clogging, segregation, or viscoplasticity.

[0091] Cone penetration refers to the depth to which a cone falls into a sample under specified load, time, and temperature conditions. It is an indicator of the consistency and hardness of sealing grease. The greater the cone penetration, the softer the sealing grease, and vice versa.

[0092] According to the test results in Table 1, the volatility of the salt-resistant shield tail sealing greases prepared in Examples 1-5 is 1.0%-1.7%, the droop value is 0.7-1.2, the cone penetration is 230-245 without the addition of sodium chloride solution, the pumpability is 46-52, and the water resistance is 4MPa without leakage. After adding 1.5wt% saturated sodium chloride solution to the salt-resistant shield tail sealing grease and mixing evenly, except for Example 2 where the performance remains unchanged, the cone penetration and pumpability of the others slightly increase. In Comparative Example 1, no salt-resistant polymer was added, and its cone penetration decreased significantly while its pumpability increased. In Comparative Example 2, after the addition of salt-resistant polyacrylamide, its cone penetration and pumpability decreased, indicating that the addition of salt-resistant polyacrylamide caused the grease system to harden. After the addition of sodium chloride, due to the presence of sodium ions, the conformation of the polymer changed, resulting in a decrease in polymer viscosity, a decrease in cone penetration, and an increase in pumpability, but leakage occurred in terms of water pressure resistance. Compared with Comparative Example 2, the sealing greases of Comparative Examples 3 and 4 are significantly better than those of Comparative Example 2; the performance of the salt-resistant sealing greases of Examples 1 to 5 is significantly better than that of the comparative examples; the performance of the salt-resistant sealing grease prepared in Example 2 of this invention reaches the performance of the sealing greases of foreign products CONDAT (Comparative Example 5) and BASF (Comparative Example 6), indicating that the salt-resistant shield tail sealing grease prepared in this invention has better performance.

[0093] In summary, the salt-resistant tail sealant of the present invention comprises at least the monomers acrylamide, diallyl dimethyl ammonium chloride, and N,N-dimethylacrylamide. Using the above three monomers as the main components and octadecyltrimethylammonium bromide as the emulsifier, a salt-resistant terpolymer is first prepared under the action of potassium persulfate as the initiator. The diallyl dimethyl ammonium chloride monomer with double bonds is added to the system by gradually adding dropwise, avoiding the random polymerization of the three monomers. The salt-resistant tail sealant prepared in this way has better cone penetration, pumpability, salt resistance, and water pressure resistance, and is suitable for high-salt areas.

[0094] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A salt-resistant shield tail sealing grease, characterized in that, The preparation method of the salt-resistant shield tail sealing grease includes the following steps: Step S1: Weigh 43 parts of emulsifier, 21 parts of acrylamide, and 20 to 25 parts of N,N-dimethylacrylamide, add them to a reaction vessel containing 900 parts of water, and continuously purge with nitrogen gas at room temperature before heating. Step S2: Mix 43 parts of emulsifier, 60-65 parts of diallyl dimethyl ammonium chloride, and 50 parts of water to obtain solution A. Mix 1.6-1.7 parts of initiator and 50 parts of water to obtain solution B. Add solution A and solution B dropwise into the reaction vessel simultaneously using a peristaltic pump. After the addition is complete, continue the reaction and cool to room temperature to obtain the reaction product. Step S3: Precipitate the reaction product obtained in step S2 with anhydrous ethanol and dry it under vacuum to obtain a salt-resistant terpolymer. Step S4: Add 50-75 parts of epoxidized soybean oil, 200-300 parts of lithium-based ester, and 2-3 parts of defoamer P803 to a kneader. Add 40-80 parts of salt-resistant terpolymer, 50-70 parts of fine cotton, and 10-15 parts of guar gum to the kneader for kneading reaction. Mix evenly to obtain salt-resistant shield tail sealing grease.

2. The salt-resistant shield tail sealing grease as described in claim 1, characterized in that, The emulsifier is selected from octadecyltrimethylammonium bromide.

3. The salt-resistant shield tail sealing grease as described in claim 1, characterized in that, The initiator is selected from potassium persulfate.

4. The salt-resistant shield tail sealing grease as described in claim 1, characterized in that, The length of the fine cotton is 25mm to 35mm, and the linear density is 2.12 to 1.56 dtex.

5. The salt-resistant shield tail sealing grease as described in claim 1, characterized in that, In step S1, nitrogen gas is continuously introduced and the temperature is raised to 70℃~80℃.

6. The salt-resistant shield tail sealing grease as described in claim 1, characterized in that, In step S2, the addition of solution A and solution B is controlled to be completed within 40 minutes and 45 minutes, respectively.

7. The salt-resistant shield tail sealing grease as described in claim 1, characterized in that, In step S2, the continued reaction time is 5h to 6h.

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