Self-adaptive expansion type shield tail sealing grease and preparation method thereof

Abstract

The invention discloses self-adaptive expansion type shield tail sealing grease and a preparation method thereof, and relates to the technical field of shield tail sealing grease, the self-adaptive expansion type shield tail sealing grease is composed of base oil, an expanding agent, a thickening and tackifying agent, a reinforcing agent, a filling agent and a modified additive; the expanding agent is composed of carboxymethyl cellulose, modified polyvinyl alcohol and modified sodium polyacrylate according to the mass ratio of (3-5): (4-7): (4-8); the self-adaptive expansion type shield tail sealing grease can make contact with underground water and shield tail slurry to achieve spontaneous expansion, the volume of the expanded shield tail sealing grease is about 1.2-1.5 times that of the shield tail sealing grease before expansion, a sealing cavity can be fully filled with the expanded shield tail sealing grease, the pressure of the sealing cavity can be increased so as to resist external grouting pressure and water and soil pressure, and the sealing effect is good. The pressure loss of the sealing cavity is compensated, the pumping frequency and pressure of shield tail sealing grease are reduced, and the grease consumption is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shield tail sealing grease, in particular to a self-adaptive expansion type shield tail sealing grease and a preparation method thereof. BACKGROUND

[0002] Shield tunneling construction is an important construction method in rail transit construction. In shield tunneling construction, shield tail sealing is a key link, and the quality of sealing directly affects the safety of construction. Shield tail sealing grease, as a sealing material for the shield tail during shield tunneling, can effectively prevent underground water, slurry and the like from entering the inside of the shield machine. In existing tunnel projects, the sealing cavity pressure can only be maintained by continuously injecting grease into the sealing cavity. In shield tunneling projects, the shield tunneling posture will be adjusted according to engineering needs. When the shield posture changes, the size of the shield tail grease sealing cavity will also change. An increased sealing cavity will cause the sealing cavity pressure to be rapidly lost, and underground water and shield tail slurry will seep in. Therefore, it is of great practical significance to develop a sealing grease that can expand and adapt to the sealing cavity pressure. SUMMARY

[0003] To solve the problem that the sealing cavity pressure can only be maintained by continuously injecting grease into the sealing cavity in tunnel projects, the purpose of the present application is to provide a self-adaptive expansion type shield tail sealing grease and a preparation method thereof. The obtained sealing grease can self-adaptively expand according to the change in the size of the sealing cavity. Underground water and slurry entering the sealing cavity will cause the sealing grease to rapidly expand, quickly fill the increased sealing cavity, restore the sealing cavity pressure, and prevent further leakage of liquid.

[0004] To achieve the above-mentioned purpose, the present application is implemented through the following technical solutions: A self-adaptive expansion type shield tail sealing grease, consisting of the following raw materials in parts by weight: 250-380 parts of base oil, 110-200 parts of an expansion agent, 120-250 parts of a thickening and viscosity increasing agent, 10-90 parts of a reinforcing agent, 250-350 parts of a filler and 15-30 parts of a modified additive. The expansion agent is composed of carboxymethyl cellulose, modified polyvinyl alcohol and modified sodium polyacrylate in a mass ratio of 3-5:4-7:4-8. The modified polyvinyl alcohol is prepared according to the following steps: Polyvinyl alcohol is dissolved in dimethyl sulfoxide, and p-toluenesulfonic acid and stearic acid are added thereto. The mixture is stirred and reacted at 85-90℃ for 6-8 hours, and then cooled to 50-60℃. The crude modified polyvinyl alcohol is obtained. The obtained crude modified polyvinyl alcohol is added to stirred acetone, and the precipitated product in the acetone is filtered out. The precipitated product is vacuum dried at 55-65℃ for 5-7 hours to obtain the modified polyvinyl alcohol. The mass ratio of polyvinyl alcohol, dimethyl sulfoxide, p-toluenesulfonic acid, stearic acid and acetone is 1:8-10:0.12-0.8:0.15-0.3:10-20. The modified sodium polyacrylate is a cross-linked sodium polyacrylate modified by a silane coupling agent.

[0005] Preferably, the silane coupling agent is hexadecyl trimethoxysilane.

[0006] Preferably, the modified sodium polyacrylate is prepared by the following steps: The cross-linked sodium polyacrylate after drying treatment and anhydrous toluene are mixed, stirred and uniformly mixed, and then heated to 80-85 DEG C. Hexadecyl trimethoxysilane is added dropwise under stirring, the dropwise adding speed is 0.2-0.4 ml / s, after the dropwise adding is completed, constant temperature stirring is carried out for 6-8 hours, the solid product is separated by suction filtration, and vacuum drying is carried out at 60-70 DEG C for 10-12 hours to obtain the modified sodium polyacrylate. The mass ratio of the cross-linked sodium polyacrylate after drying treatment, anhydrous toluene and hexadecyl trimethoxysilane is 1:10-15:0.01-0.03.

[0007] Preferably, the base oil is composed of epoxy soybean oil and 150N mineral oil according to the mass ratio of 3-7:3-7.

[0008] Preferably, the thickening and viscosity increasing agent is composed of polyisobutylene, lithium magnesium silicate and polymerized rosin according to the mass ratio of 6-13:2-5:4-7.

[0009] Preferably, the reinforcing agent is composed of kapok fiber and polypropylene fiber according to the mass ratio of 3-30:2-15.

[0010] Preferably, the filler is composed of expanded perlite, calcium carbonate and acrylic bentonite according to the mass ratio of 3-5:18-25:3-5.

[0011] Preferably, the modified additive is composed of a titanate coupling agent and zinc stearate according to the mass ratio of 1-2:1-5.

[0012] Preferably, the viscosity of 1% aqueous solution of carboxymethyl cellulose at 25 DEG C is 180-220 mPa s.

[0013] The application also includes a preparation method of the self-adaptive expansion type shield tail sealing grease, which comprises the following steps: The modified additive 15-30 parts by weight, the thickening and tackifying agent 120-250 parts by weight are added into the base oil 250-380 parts by weight, the temperature is raised to 85-95 DEG C, and stirring is carried out for 20-40 minutes, and the temperature is lowered to 30-40 DEG C to obtain a mixture; the expanding agent 110-200 parts by weight is added into the mixture and stirred uniformly, the reinforcing agent 10-90 parts by weight and the filler 250-350 parts by weight are added into the mixture in sequence and stirred uniformly to obtain the self-adapting expanding shield tail sealing grease.

[0014] Preferably, the rotating speed during stirring is 125-300 rpm.

[0015] Compared with the prior art, the self-adapting expanding shield tail sealing grease has the following advantages: The self-adapting expanding shield tail sealing grease can contact with underground water and shield tail slurry, and can realize self-expansion, and the volume after expansion is about 1.3 times of the volume before expansion, the shield tail sealing grease after expansion can fully fill the sealing cavity and increase the pressure of the sealing cavity to resist external grouting pressure and water and soil pressure, compensate the pressure loss of the sealing cavity, reduce the pumping frequency and pressure of the shield tail sealing grease, and reduce the consumption of the grease.

[0016] The self-adapting expanding shield tail sealing grease can realize the size change of the self-adapting shield tail sealing cavity, and the underground water and slurry entering the sealing cavity can make the sealing grease rapidly expand, rapidly fill the increased sealing cavity, restore the pressure of the sealing cavity, and prevent further leakage of the liquid. DETAILED DESCRIPTION

[0017] The purpose of the present application is to provide a self-adapting expanding shield tail sealing grease and a preparation method thereof, which is realized by the following technical scheme: The carboxymethyl cellulose selected in the embodiment of the present application has a viscosity of 200 mPa·s in a 1% aqueous solution at 25 DEG C, the alcoholysis degree of the polyvinyl alcohol is 98-100%, the mesh number of the sodium polyacrylate is 400 meshes, the molecular weight of the polyisobutylene is 2400, the mesh number of the magnesium lithium silicate is 325 meshes, the softening point of the polymerized rosin is 90 DEG C, the density of the titanate coupling agent is about 0.946 g / cm3, the mesh number of the zinc stearate is 325 meshes, the fiber length of the kapok fiber is 4-8 mm, the fiber length of the polypropylene fiber is 6-13 mm, the mesh number of the calcium carbonate is 400 meshes, and the mesh number of the expanded perlite is 325 meshes.

[0018] The acrylic bentonite is purchased from the BYK company, and the model is OPTIGEL CK.

[0019] The carboxymethyl cellulose, the modified polyvinyl alcohol and the modified sodium polyacrylate are used in a mass ratio of 3-5:4-7:4-8 to obtain the expanding agent. The expanding mechanism is as follows: Carboxymethyl cellulose, modified polyvinyl alcohol, and modified sodium polyacrylate cooperate with each other to achieve the self-adaptive expansion effect of rapid response, effective support, and pressure supplement. Carboxymethyl cellulose (CMC) with the best hydrophilicity first rapidly absorbs water, and the osmotic pressure generated by the sodium carboxylate groups on the molecular chain of CMC actively captures water molecules. The long-chain fiber structure of CMC stretches after absorbing water and is intertwined with each other through interchain hydrogen bonds to form the initial three-dimensional network structure of the entire expansion system. The sodium polyacrylate modified by hexadecyl trimethoxysilane is slowly activated in the network established by CMC and absorbs a large amount of water by using its own sodium carboxylate groups. At the same time, the hydrophobic siloxane limits the unlimited swelling of the sodium polyacrylate chain and prevents the system from collapsing in water; on the other hand, it converts the expansion force of the sodium polyacrylate into a sustained opening of the entire gel network, making the expansion body more strong and elastic and increasing the pressure of the grease sealing cavity. The remaining hydrophilic hydroxyl groups on the molecular chain of the modified polyvinyl alcohol further attract water and improve the expansion capacity of the material. At the same time, the hydrophobic long alkane chains brought by the modification spontaneously gather together in water through hydrophobic interaction to form physical crosslinking points similar to hydrophobic microzones. These microzones enhance the mechanical toughness of the gel and constitute a water barrier to effectively slow down the diffusion of water and maintain the stability of the expansion body.

[0020] The application will be further described below in combination with specific examples. Example 1

[0021] A self-adaptive expansion type shield tail sealing grease is composed of the following raw materials: 250 kg of base oil, 110 kg of expansion agent, 120 kg of thickening and tackifying agent, 10 kg of reinforcing agent, 250 kg of filler, and 15 kg of modified additive; The base oil is composed of epoxy soybean oil and 150N mineral oil in a mass ratio of 3:7; The thickening and tackifying agent is composed of polyisobutylene, magnesium lithium silicate, and polymerized rosin in a mass ratio of 6:2:7; The reinforcing agent is composed of kapok fiber and polypropylene fiber in a mass ratio of 3:15; The filler is composed of expanded perlite, calcium carbonate, and acrylic bentonite in a mass ratio of 3:18:5; The modified additive is composed of titanium ester coupling agent and zinc stearate in a mass ratio of 1:5; The expansion agent is composed of carboxymethyl cellulose, modified polyvinyl alcohol, and modified sodium polyacrylate in a mass ratio of 3:4:4; The modified polyvinyl alcohol is prepared according to the following steps: The polyvinyl alcohol is dissolved in dimethyl sulfoxide, p-toluenesulfonic acid and stearic acid are added thereto, and the mixture is stirred and reacted at 85℃ for 6 hours, and then cooled to 50℃ to obtain crude modified polyvinyl alcohol; the crude modified polyvinyl alcohol is added to stirred acetone, and the precipitated product is filtered out, and then vacuum dried at 55℃ for 5 hours to obtain modified polyvinyl alcohol; The mass ratio of polyvinyl alcohol, dimethyl sulfoxide, p-toluenesulfonic acid, stearic acid and acetone is 1:8:0.12:0.15:10; The modified sodium polyacrylate is a cross-linked sodium polyacrylate modified by a silane coupling agent, and is prepared according to the following steps: The cross-linked sodium polyacrylate after drying treatment and anhydrous toluene are mixed and stirred uniformly, heated to 80℃, and then hexadecyl trimethoxysilane is added dropwise thereto at a speed of 0.2ml / s, and then stirred at constant temperature for 8 hours after the addition is completed, and then the solid product is separated by suction filtration, and then vacuum dried at 60℃ for 10 hours to obtain modified sodium polyacrylate; the mass ratio of the cross-linked sodium polyacrylate after drying treatment, anhydrous toluene and hexadecyl trimethoxysilane is 1:10:0.01. Example 2

[0022] An adaptive expansion type shield tail sealing grease is composed of base oil 380kg, expanding agent 200kg, thickening and tackifying agent 250kg, reinforcing agent 90kg, filler 350kg and modified additive 30kg; The base oil is composed of epoxy soybean oil and 150N mineral oil according to a mass ratio of 7:3; The thickening and tackifying agent is composed of polyisobutylene, magnesium lithium silicate and polymerized rosin according to a mass ratio of 13:5:4; The reinforcing agent is composed of kapok fiber and polypropylene fiber according to a mass ratio of 15:1; The filler is composed of expanded perlite, calcium carbonate and acrylic bentonite according to a mass ratio of 5:25:3; The modified additive is composed of titanate coupling agent and zinc stearate according to a mass ratio of 2:1; The expanding agent is composed of carboxymethyl cellulose, modified polyvinyl alcohol and modified sodium polyacrylate according to a mass ratio of 5:7:8; The modified polyvinyl alcohol is prepared according to the following steps: The polyvinyl alcohol is dissolved in dimethyl sulfoxide, p-toluenesulfonic acid and stearic acid are added thereto, and the mixture is stirred and reacted at 85℃ for 6 hours, and then cooled to 50℃ to obtain crude modified polyvinyl alcohol; the crude modified polyvinyl alcohol is added to stirred acetone, and the precipitated product is filtered out, and then vacuum dried at 55℃ for 5 hours to obtain modified polyvinyl alcohol; The mass ratio of polyvinyl alcohol, dimethyl sulfoxide, p-toluenesulfonic acid, stearic acid and acetone is 1:10:0.8:0.3:20; The modified sodium polyacrylate is a cross-linked sodium polyacrylate modified by a silane coupling agent, and is prepared according to the following steps: The cross-linked sodium polyacrylate after drying treatment and anhydrous toluene are mixed, stirred and uniformly mixed, and then heated to 85°C. Hexadecyl trimethoxysilane is added dropwise under stirring, the dropping speed is 0.4ml / s, after the dropping is completed, constant temperature stirring is carried out for 6 hours, the solid product is separated by suction filtration, and then vacuum drying is carried out at 70°C for 10 hours to obtain the modified sodium polyacrylate. The mass ratio of the cross-linked sodium polyacrylate after drying treatment, anhydrous toluene and hexadecyl trimethoxysilane is 1:15:0.03. Example 3

[0023] An adaptive expansion type shield tail sealing grease is composed of base oil 300kg, expanding agent 140kg, thickening and tackifying agent 220kg, reinforcing agent 80kg, filler 280kg and modified additive 16kg; The base oil is composed of epoxy soybean oil and 150N mineral oil according to a mass ratio of 4:6; The thickening and tackifying agent is composed of polyisobutylene, lithium magnesium silicate and polymerized rosin according to a mass ratio of 7:3:5; The reinforcing agent is composed of kapok fiber and polypropylene fiber according to a mass ratio of 5:8; The filler is composed of expanded perlite, calcium carbonate and acrylic bentonite according to a mass ratio of 1:5:1; The modified additive is composed of titanate coupling agent and zinc stearate according to a mass ratio of 3:4; The expanding agent is composed of carboxymethyl cellulose, modified polyvinyl alcohol and modified sodium polyacrylate according to a mass ratio of 4:5:7; The modified polyvinyl alcohol is prepared according to the following steps: Polyvinyl alcohol is dissolved in dimethyl sulfoxide, p-toluenesulfonic acid and stearic acid are added, stirring reaction is carried out at 86°C for 7 hours, the temperature is lowered to 52°C, and the crude modified polyvinyl alcohol is obtained. The obtained crude modified polyvinyl alcohol is added to stirring acetone, the precipitated product in acetone is filtered out, and the precipitated product is vacuum dried at 56°C for 5.5 hours to obtain the modified polyvinyl alcohol; The mass ratio of polyvinyl alcohol, dimethyl sulfoxide, p-toluenesulfonic acid, stearic acid and acetone is 1:8.5:0.3:0.2:12; The modified sodium polyacrylate is a cross-linked sodium polyacrylate modified by a silane coupling agent, and is prepared according to the following steps: The cross-linked sodium polyacrylate after drying treatment and anhydrous toluene are mixed, stirred and uniformly mixed, heated to 82℃, and hexadecyl trimethoxysilane is added dropwise thereto under stirring, the dropping speed is 0.25ml / s, after the dropping is completed, constant temperature stirring is carried out for 6.5 hours, the solid product is separated by suction filtration, and vacuum drying is carried out at 62℃ for 10.5 hours to obtain modified sodium polyacrylate; wherein the mass ratio of the cross-linked sodium polyacrylate after drying treatment, anhydrous toluene and hexadecyl trimethoxysilane is 1:12:0.02. Example 4

[0024] An adaptive expansion type shield tail sealing grease is composed of base oil 320kg, expanding agent 180kg, thickening and tackifying agent 150kg, reinforcing agent 20kg, filler 320kg and modified additive 28kg; The base oil is composed of epoxy soybean oil and 150N mineral oil according to a mass ratio of 5:6; The thickening and tackifying agent is composed of polyisobutylene, magnesium lithium silicate and polymerized rosin according to a mass ratio of 8:3:5; The reinforcing agent is composed of kapok fiber and polypropylene fiber according to a mass ratio of 20:7; The filler is composed of expanded perlite, calcium carbonate and acrylic bentonite according to a mass ratio of 4:22:3; The modified additive is composed of titanium ester coupling agent and zinc stearate according to a mass ratio of 8:15; The expanding agent is composed of carboxymethyl cellulose, modified polyvinyl alcohol and modified sodium polyacrylate according to a mass ratio of 4:6:5; The modified polyvinyl alcohol is prepared according to the following steps: Polyvinyl alcohol is dissolved in dimethyl sulfoxide, p-toluenesulfonic acid and stearic acid are added thereto, stirring reaction is carried out at 88℃ for 7.5 hours, the temperature is lowered to 58℃, and the crude modified polyvinyl alcohol is obtained; the obtained crude modified polyvinyl alcohol is added to stirring acetone, the precipitated product in acetone is filtered out, and the precipitated product is vacuum dried at 62℃ for 6.5 hours to obtain modified polyvinyl alcohol; The mass ratio of polyvinyl alcohol, dimethyl sulfoxide, p-toluenesulfonic acid, stearic acid and acetone is 1:9.5:0.5:0.18:18; The modified sodium polyacrylate is cross-linked sodium polyacrylate modified by silane coupling agent, and is prepared according to the following steps: The cross-linked sodium polyacrylate after drying treatment and anhydrous toluene are mixed, stirred and uniformly mixed, heated to 84℃, and hexadecyl trimethoxysilane is added dropwise thereto at a dropwise adding speed of 0.35ml / s, after the dropwise adding is completed, constant temperature stirring is carried out for 7.5 hours, the solid product is separated by suction filtration, and vacuum drying is carried out at 68℃ for 11.5 hours to obtain modified sodium polyacrylate; wherein the mass ratio of the cross-linked sodium polyacrylate after drying treatment, anhydrous toluene and hexadecyl trimethoxysilane is 1:14:0.025. Example 5

[0025] An adaptive expansion type shield tail sealing grease is composed of base oil 300kg, expansion agent 150kg, thickening and tackifying agent 200kg, reinforcing agent 50kg, filler 300kg and modified additive 20kg; The base oil is composed of epoxy soybean oil and 150N mineral oil according to a mass ratio of 4:5; The thickening and tackifying agent is composed of polyisobutylene, magnesium lithium silicate and polymerized rosin according to a mass ratio of 12:4:5; The reinforcing agent is composed of kapok fiber and polypropylene fiber according to a mass ratio of 25:7; The filler is composed of expanded perlite, calcium carbonate and acrylic bentonite according to a mass ratio of 1:5:1; The modified additive is composed of titanium ester coupling agent and zinc stearate according to a mass ratio of 3:8; The expansion agent is composed of carboxymethyl cellulose, modified polyvinyl alcohol and modified sodium polyacrylate according to a mass ratio of 4:5:6; The modified polyvinyl alcohol is prepared according to the following steps: Polyvinyl alcohol is dissolved in dimethyl sulfoxide, p-toluenesulfonic acid and stearic acid are added thereto, stirring reaction is carried out at 88℃ for 7 hours, the temperature is lowered to 55℃, and the crude modified polyvinyl alcohol is obtained; the obtained crude modified polyvinyl alcohol is added to stirring acetone, the precipitated product in the acetone is filtered out, and the precipitated product is vacuum dried at 60℃ for 6 hours to obtain modified polyvinyl alcohol; The mass ratio of polyvinyl alcohol, dimethyl sulfoxide, p-toluenesulfonic acid, stearic acid and acetone is 1:9:0.5:0.2:15; The modified sodium polyacrylate is cross-linked sodium polyacrylate modified by silane coupling agent, and is prepared according to the following steps: The cross-linked sodium polyacrylate after drying treatment and anhydrous toluene are mixed, stirred and uniformly mixed, heated to 84°C, and hexadecyl trimethoxysilane is added dropwise thereto under stirring, the dropping speed is 0.3ml / s, after the dropping is completed, constant temperature stirring is carried out for 7 hours, the solid product is separated by suction filtration, vacuum drying is carried out at 65°C for 11 hours, and the modified sodium polyacrylate is obtained; wherein the mass ratio of the cross-linked sodium polyacrylate after drying treatment, anhydrous toluene and hexadecyl trimethoxysilane is 1:12:0.02. Example 6

[0026] The preparation method of the self-adaptive expansion type shield tail sealing grease described in Example 1 comprises the following steps: The 15kg modified additive, 120kg thickening and tackifying agent are added into 250kg base oil, heated to 85°C, stirred at 125rpm for 40 minutes, cooled to 30°C, and a mixture is obtained; 110kg expanding agent is added into the mixture and stirred uniformly at 125rpm, 10kg reinforcing agent and 250kg filler are sequentially added into the mixture and stirred uniformly at 125rpm, and the self-adaptive expansion type shield tail sealing grease is obtained. Example 7

[0027] The preparation method of the self-adaptive expansion type shield tail sealing grease described in Example 2 comprises the following steps: The 30kg modified additive, 250kg thickening and tackifying agent are added into 380kg base oil, heated to 95°C, stirred at 300rpm for 20 minutes, cooled to 40°C, and a mixture is obtained; 200kg expanding agent is added into the mixture and stirred uniformly at 300rpm, 90kg reinforcing agent and 350kg filler are sequentially added into the mixture and stirred uniformly at 300rpm, and the self-adaptive expansion type shield tail sealing grease is obtained. Example 8

[0028] The preparation method of the self-adaptive expansion type shield tail sealing grease described in Example 3 comprises the following steps: The 16kg modified additive, 220kg thickening and tackifying agent are added into 300kg base oil, heated to 90°C, stirred at 200rpm for 25 minutes, cooled to 32°C, and a mixture is obtained; 140kg expanding agent is added into the mixture and stirred uniformly at 150rpm, 80kg reinforcing agent and 280kg filler are sequentially added into the mixture and stirred uniformly at 180rpm, and the self-adaptive expansion type shield tail sealing grease is obtained. Example 9

[0029] The preparation method of the self-adaptive expansion type shield tail sealing grease described in Example 4 comprises the following steps: To 320 kg base oil, 28 kg modified additive, 150 kg thickening and tackifying agent are added, the temperature is raised to 88 DEG C, stirring at 150 rpm for 35 minutes, the temperature is lowered to 36 DEG C, to obtain a mixture; To the mixture, 180 kg of the expanding agent is added, stirring at 220 rpm until uniform, 20 kg of the reinforcing agent and 320 kg of the filler are added in turn, stirring at 250 rpm until uniform, to obtain the self-adapting expanding shield tail sealing grease. Example 10

[0030] The preparation method of the self-adapting expanding shield tail sealing grease described in Example 5, comprising the following steps: To 300 kg base oil, 20 kg modified additive, 200 kg thickening and tackifying agent are added, the temperature is raised to 90 DEG C, stirring at 200 rpm for 30 minutes, the temperature is lowered to 35 DEG C, to obtain a mixture; To the mixture, 150 kg of the expanding agent is added, stirring at 200 rpm until uniform, 50 kg of the reinforcing agent and 300 kg of the filler are added in turn, stirring at 200 rpm until uniform, to obtain the self-adapting expanding shield tail sealing grease.

[0031] The self-adapting expanding shield tail sealing grease obtained in Examples 6-10 is subjected to performance testing, wherein the pumpability, water pressure resistance and cone penetration are detected according to T / CC 8-2023 method, and the expansion rate is detected according to the following method: a certain mass of shield tail sealing grease sample is added to the expansion degree measuring tube, compacted and the pre-expansion volume is read. Then 2 times the mass of the sample of water is added, and after standing for 1 h, the post-expansion volume is read, and the expansion rate = (post-expansion volume-pre-expansion volume) / pre-expansion volume. The results are shown in Table 1.

[0032] Table 1 Performance test results of the self-adapting expanding shield tail sealing grease obtained in Examples 6-10 Pumpability (g / min) Swelling ratio (%) Water pressure resistance (MPa) Taper (0.1 mm) Example 6 36.1 18.5 6.5 218.7 Example 7 19.8 35.1 7.7 204.5 Example 8 27.1 28.5 7.5 209.7 Example 9 30.2 25.2 7.0 212.2 Example 10 28.4 37.4 7.0 205.1 As can be seen from the results in Table 1, the self-adapting expanding shield tail sealing grease has good pumpability, water pressure resistance and cone penetration, and can contact with underground water and shield tail slurry to realize self-expansion, and the volume after expansion is about 1.3 times that before expansion.

Claims

1. An adaptive expansion type shield tail sealing grease, characterized in that: By weight, it is composed of the following raw materials: 250-380 parts base oil, 110-200 parts expander, 120-250 parts thickener and viscous agent, 10-90 parts reinforcing agent, 250-350 parts filler and 15-30 parts modifying additive. The expanding agent is composed of carboxymethyl cellulose, modified polyvinyl alcohol, and modified sodium polyacrylate in a mass ratio of 3~5:4~7:4~8; The modified polyvinyl alcohol was prepared according to the following steps: Polyvinyl alcohol was dissolved in dimethyl sulfoxide, p-toluenesulfonic acid and stearic acid were added, and the mixture was stirred at 85-90°C for 6-8 hours. The mixture was then cooled to 50-60°C to obtain crude modified polyvinyl alcohol. The obtained crude modified polyvinyl alcohol was added to acetone under stirring, and the precipitate was filtered out. The precipitate was then vacuum dried at 55-65°C for 5-7 hours to obtain modified polyvinyl alcohol. The mass ratio of polyvinyl alcohol, dimethyl sulfoxide, p-toluenesulfonic acid, stearic acid, and acetone is 1:8~10:0.12~0.8:0.15~0.3:10~20; The modified sodium polyacrylate is a cross-linked sodium polyacrylate modified with a silane coupling agent.

2. The adaptive expansion shield tail sealing grease according to claim 1, characterized in that: The silane coupling agent is hexadecyltrimethoxysilane.

3. The adaptive expansion shield tail sealing grease according to claim 1, characterized in that: The modified sodium polyacrylate is prepared according to the following steps: The dried cross-linked sodium polyacrylate and anhydrous toluene were mixed and stirred until homogeneous. The mixture was heated to 80-85°C, and hexadecyltrimethoxysilane was added dropwise at a rate of 0.2-0.4 ml / s while stirring. After the addition was complete, the mixture was stirred at a constant temperature for 6-8 hours. The solid product was separated by filtration and then dried under vacuum at 60-70°C for 10-12 hours to obtain modified sodium polyacrylate. The mass ratio of the dried cross-linked sodium polyacrylate, anhydrous toluene, and hexadecyltrimethoxysilane is 1:10~15:0.01~0.

03.

4. The adaptive expansion shield tail sealing grease according to claim 1, characterized in that: The base oil is composed of epoxidized soybean oil and 150N mineral oil in a mass ratio of 3~7:3~7.

5. The adaptive expansion shield tail sealing grease according to claim 1, characterized in that: The thickening and tackifying agent is composed of polyisobutylene, lithium magnesium silicate, and polymeric rosin in a mass ratio of 6~13:2~5:4~7.

6. The adaptive expansion shield tail sealing grease according to claim 1, characterized in that: The reinforcing agent is composed of kapok fiber and polypropylene fiber in a mass ratio of 3~30:2~15.

7. The adaptive expansion shield tail sealing grease according to claim 1, characterized in that: The filler is composed of expanded perlite, calcium carbonate and acrylic bentonite in a mass ratio of 3~5:18~25:3~5.

8. The adaptive expansion shield tail sealing grease according to claim 1, characterized in that: The modified additive is composed of titanate coupling agent and zinc stearate in a mass ratio of 1~2:1~5.

9. The method for preparing an adaptive expansion type shield tail sealing grease according to claim 1, characterized in that: Includes the following steps: By weight, add 15-30 parts of modified additive and 120-250 parts of thickener to 250-380 parts of base oil, heat to 85-95℃, stir for 20-40 minutes, and cool to 30-40℃ to obtain a mixture; add 110-200 parts of expander to the mixture and stir until homogeneous; then add 10-90 parts of reinforcing agent and 250-350 parts of filler to the mixture and stir until homogeneous to obtain an adaptive expansion shield tail sealing grease.

10. The method for preparing an adaptive expansion type shield tail sealing grease according to claim 9, characterized in that: The stirring speed should be 125~300 rpm when mixing.