Shield tail lubricating grease for shield machine and preparation method thereof

Abstract

The present invention relates to the technical field of lubricating grease, and in particular to a shield tail lubricating grease for a shield machine and a preparation method thereof, which comprises the following components by weight: 25-55 parts of base oil, 10-25 parts of fiber material, 20-40 parts of filler, 10-30 parts of viscosity promoter and 15-25 parts of lubricant, wherein the lubricant is a modified nano-silicon dioxide-modified graphene composite material. The present invention adopts a shield tail lubricating grease for a shield machine with the above structure and a preparation method thereof, which solves the problems of low lubricity, poor adhesion and low pumping efficiency of the shield tail lubricating grease in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of lubricating grease, in particular to a shield tail lubricating grease for a shield machine and a preparation method thereof. Background Art

[0002] At present, my country's underground transportation is developing rapidly. In order to build underground projects without affecting the existing ground buildings, the commonly used construction methods are shield method or pipe jacking method. Shield machine is a construction machine used in tunnel construction. It can play a supporting role in excavating the stratum and assembling the lining.

[0003] During the construction of the shield machine, shield tail grease is used in the tail sealing device of the shield tunneling machine. It plays the role of lubrication, waterproof sealing, and corrosion prevention. It can effectively isolate groundwater, mud and protect the shield tail brush. It is a key material in the shield construction process and directly affects the safety of construction.

[0004] However, the shield tail grease in the prior art still has the problems of low lubricity, poor adhesion and low pumping efficiency, which cannot effectively reduce the friction between the shield tail and the pipe segment, and affects the waterproof effect and filling effect of the sealing layer. Summary of the invention

[0005] The purpose of the invention is to provide a shield tail lubricating grease for a shield machine and a preparation method thereof, which solves the problems of low lubricity, poor adhesion and low pumping efficiency of the shield tail lubricating grease in the prior art.

[0006] To achieve the above-mentioned purpose, the present invention provides a shield tail lubricating grease for a shield machine, which comprises the following components by weight: 25-55 parts of base oil, 10-25 parts of fiber material, 20-40 parts of filler, 10-30 parts of viscosity promoter and 15-25 parts of lubricant, wherein the lubricant is a modified nano-silicon dioxide-modified graphene composite material.

[0007] Preferably, the base oil is one or more of mineral oil, vegetable oil or synthetic oil. The present invention has no special requirements on the source of the base oil, and commercially available products known to those skilled in the art can be used.

[0008] More preferably, the mineral oil includes one or more of naphthenic base oil and paraffinic base oil.

[0009] More preferably, the vegetable oil includes one or more of corn oil, soybean oil, peanut oil, and castor oil.

[0010] More preferably, the synthetic oil includes one or more of pentaerythritol ester, dioctyl terephthalate, and poly-α-olefin synthetic oil.

[0011] Preferably, the fiber material is degradable wood fiber, and the length of the fiber material is 0.1-2 mm. The present invention has no special requirements on the source of the fiber material, and commercially available products known to those skilled in the art can be used.

[0012] Preferably, the filler includes one or more of light calcium carbonate, bentonite, kaolin, mica, and talc. The present invention has no special requirements on the source of the filler, and commercial products well known to those skilled in the art can be used.

[0013] Preferably, the viscosity promoter is one or more of polyacrylamide, N,N-dimethylacrylamide, 2-hydroxysuccinic acid and 3-hydroxy-1,3,5-pentanetriolic acid. In the present invention, the viscosity of the grease is increased by adding the viscosity promoter, thereby improving the adhesion and sealing of the shield tail grease.

[0014] Preferably, the modified nano-silicon dioxide-modified graphene composite material comprises nano-silicon dioxide modified by a silane coupling agent and multi-layer graphene oxide modified by a silane coupling agent. The present invention uses the modified nano-silicon dioxide-modified graphene composite material as a lubricant, improves the lubricity of the shield tail grease through the lubrication properties of the nano-silicon dioxide and graphene, reduces the friction between the shield tail and the pipe segment, and also improves the pumpability of the shield tail grease.

[0015] The lubricant of the present invention uses multi-layer graphene oxide as a skeleton, and nano-silicon dioxide is grafted onto the surface of the graphene, thereby improving the dispersibility of the graphene in the base grease and avoiding the coagulation or agglomeration of the graphene. In addition, the nano-silicon dioxide and the multi-layer graphene oxide are both grafted and modified by a silane coupling agent, so that the surfaces of the nano-silicon dioxide and the multi-layer graphene oxide have a large number of cross-linking groups. While improving the grafting rate of the nano-silicon dioxide and the graphene, the binding ability of the nano-silicon dioxide and the graphene with the base grease is further improved, thereby strengthening the toughness and bonding strength of the shield tail lubricating grease, that is, improving the adhesion of the shield tail lubricating grease.

[0016] A method for preparing shield tail lubricating grease for a shield machine comprises the following steps:

[0017] (1) first adding a viscosity promoter to a base oil, stirring at room temperature until the base oil and the viscosity promoter are completely mixed, and then stopping stirring to obtain a mixture of the base oil and the viscosity promoter;

[0018] (2) After adding lubricant to the mixture of base oil and viscosity promoter and continuing stirring for 1-1.5 hours, fiber material and filler are added and continuing stirring for 2-3 hours to obtain shield tail grease.

[0019] Preferably, the preparation of the lubricant in (2) comprises the following steps:

[0020] S1 prepares modified nano-silica, disperses nano-silica powder in an ethanol solution to prepare a suspension A, and adds sodium hydroxide to the suspension A to adjust the pH; mixes a silane coupling agent with methyl methacrylate, and drips the mixture into the suspension A, raises the temperature to 80-90° C., disperses the mixture under magnetic stirring for 2-3 hours, and cools the mixture to room temperature to obtain a modified nano-silica suspension;

[0021] S2 prepares modified graphene, adds multilayer graphene oxide to anhydrous ethanol to prepare suspension B, adds oxalic acid to suspension B to adjust pH, mixes silane coupling agent with anhydrous ethanol, and then drops the mixture into suspension B, reacts with magnetic stirring at 40-60° C. for 5-6 hours, and obtains modified multilayer graphene oxide after centrifugation and drying;

[0022] S3: hydrolyzing the modified nano-silica suspension and the modified multilayer graphene oxide in an ethanol solution to obtain a modified graphene composite material loaded with the modified nano-silica.

[0023] Preferably, the solid-liquid ratio of nano-silicon dioxide to ethanol solution in S1 is 1:40-50, the mass fraction of sodium hydroxide is 8%, and the pH is 7-8; the solid-liquid ratio of multilayer graphene oxide to anhydrous ethanol in S2 is 1:40-50, and the pH is 5-6.

[0024] Preferably, the hydrolysis reaction in S3 is to mix the modified nano-silica suspension and the modified multilayer graphene oxide with an ethanol solution, firstly perform a pre-hydrolysis reaction under acidic conditions at 15°C-35°C for 40h-80h, and then continue the hydrolysis reaction under alkaline conditions at 50-80°C for 1h-2h.

[0025] Beneficial effects of the present invention:

[0026] The present invention uses base oil, fiber material and filler as basic raw materials, improves the adhesion of shield tail grease by adding viscosity promoter, improves the lubricity and pumpability of shield tail grease by adding lubricant, and the lubricant used in the present invention is a composite material of nano silicon dioxide modified by silane coupling agent and multilayer graphene oxide modified by silane coupling agent, the lubricity of shield tail grease is improved by nano silicon dioxide and graphene, and graphene is used as a skeleton to load nano silicon dioxide on graphene to improve the dispersibility of graphene and silicon dioxide, nano silicon dioxide and multilayer graphene oxide are both modified by silane coupling agent, further improving the dispersibility of nano silicon dioxide and multilayer graphene oxide, and also improving their ability to combine with basic grease, thereby also improving the adhesion of shield tail grease. That is, the shield tail grease prepared by the present invention has excellent lubricity, pumpability and adhesion, low production cost, and can be widely used in shield engineering.

[0027] The technical solution of the present invention is further described in detail below through embodiments. DETAILED DESCRIPTION

[0028] The present invention is further described below by way of examples. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs. The above-mentioned features or features mentioned in the specific examples mentioned in the present invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0029] The lubricant used in the present invention is prepared by the following steps:

[0030] S1 prepared modified nano-silica, dispersed nano-silica powder into ethanol solution at a solid-liquid ratio of 1:45 to prepare suspension A, and added 8% sodium hydroxide by mass to suspension A to adjust the pH to 8; mixed silane coupling agent KH560 with methyl methacrylate, and slowly dripped into suspension A, raised to 85°C, dispersed under magnetic stirring for 3h, and cooled to room temperature to obtain modified nano-silica suspension;

[0031] S2 prepares modified graphene, adds multilayer graphene oxide to anhydrous ethanol at a solid-liquid ratio of 1:45 to prepare suspension B, adds oxalic acid to suspension B to adjust the pH to 6, mixes silane coupling agent with anhydrous ethanol, and then drops the mixture into suspension B, reacts at 50° C. with magnetic stirring for 6 h, and obtains modified multilayer graphene oxide after centrifugation and drying;

[0032] S3: Mix the modified nano-silicon dioxide suspension and the modified multilayer graphene oxide with the ethanol solution, pre-hydrolyze for 60 hours at 35°C under acidic conditions, and then continue to hydrolyze for 2 hours at 72°C under alkaline conditions to obtain a modified graphene composite material loaded with modified nano-silicon dioxide, which is the lubricant used in the present invention.

[0033] Example 1

[0034] The invention provides a shield tail lubricating grease for a shield machine, which comprises the following components by weight: 25 parts of cycloalkyl base oil, 10 parts of degradable wood fiber, 20 parts of light calcium carbonate, 10 parts of polyacrylamide and 15 parts of lubricant.

[0035] Example 2

[0036] The invention provides a shield tail lubricating grease for a shield machine, which comprises the following components by weight: 30 parts of soybean oil, 15 parts of degradable wood fiber, 25 parts of light calcium carbonate, 15 parts of polyacrylamide and 20 parts of lubricant.

[0037] Example 3

[0038] The invention provides a shield tail lubricating grease for a shield machine, which comprises the following components by weight: 35 parts of pentaerythritol ester, 20 parts of degradable wood fiber, 30 parts of mica, 20 parts of N,N-dimethylacrylamide and 20 parts of lubricant.

[0039] Example 4

[0040] The invention provides a shield tail lubricating grease for a shield machine, which comprises the following components by weight: 40 parts of paraffin base oil, 25 parts of degradable wood fiber, 35 parts of talcum powder, 25 parts of 2-hydroxysuccinic acid and 20 parts of lubricant.

[0041] Example 5

[0042] The invention provides a shield tail lubricating grease for a shield machine, which comprises the following components by weight: 55 parts of poly-alpha-olefin synthetic oil, 25 parts of degradable wood fiber, 40 parts of talcum powder, 30 parts of 3-hydroxy-1,3,5-pentanetriolic acid and 25 parts of lubricant.

[0043] Example 6

[0044] Based on Example 1, the present invention provides a method for preparing a shield tail lubricating grease for a shield machine, comprising the following steps:

[0045] (1) First, add 10 parts of polyacrylamide to 25 parts of cycloalkyl base oil.

[0046] Stirring at room temperature until the cycloalkyl base oil and the polyacrylamide are completely mixed, then stopping stirring to obtain a mixture of the base oil and the viscosity promoter;

[0047] (2) After adding 15 parts of lubricant to the mixture of base oil and viscosity promoter and continuing to stir for 1.5 hours, 10 parts of degradable wood fiber and 20 parts of light calcium carbonate are added and continuing to stir for 3 hours to obtain shield tail grease.

[0048] Comparative Example 1

[0049] The example 5 was used as a reference, but the difference from the example 5 was that no lubricant was added.

[0050] The performance test was performed on the shield tail lubricating grease prepared in Examples 1-5 and Comparative Example 1. The performance test results are shown in Table 1.

[0051] Table 1 Performance data of Examples 1-5 and Comparative Example 1

[0052]

[0053] It can be seen from Table 1 that the shield tail grease prepared by the present invention has excellent pumping performance, greatly reduces the problem of clogging of the grease injection pipe during the use of the shield machine, improves work efficiency, and also has excellent adhesion and stability. The droop value at 50°C and 5h is less than 0.2mm; at 38°C and 2.8bar pressure, the wash-out amount after water washing for 5min is less than 2%.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A shield tail lubricating grease for a shield machine, characterized in that: The composition comprises the following components by weight: 25-55 parts of base oil, 10-25 parts of fiber material, 20-40 parts of filler, 10-30 parts of viscosity promoter and 15-25 parts of lubricant, wherein the lubricant is a modified nano-silicon dioxide-modified graphene composite material; the modified nano-silicon dioxide-modified graphene composite material is nano-silicon dioxide modified by a silane coupling agent and multi-layer graphene oxide modified by a silane coupling agent; The preparation of lubricant is as follows: S1 prepares modified nano-silica, disperses nano-silica powder in an ethanol solution to prepare a suspension A, and adds sodium hydroxide to the suspension A to adjust the pH; mixes a silane coupling agent with methyl methacrylate, and drips the mixture into the suspension A, raises the temperature to 80-90° C., disperses the mixture under magnetic stirring for 2-3 hours, and cools the mixture to room temperature to obtain a modified nano-silica suspension; S2 prepares modified graphene, adds multilayer graphene oxide to anhydrous ethanol to prepare suspension B, adds oxalic acid to suspension B to adjust pH, mixes silane coupling agent with anhydrous ethanol, and then drops the mixture into suspension B, reacts with magnetic stirring at 40-60° C. for 5-6 hours, and obtains modified multilayer graphene oxide after centrifugation and drying; S3: hydrolyzing the modified nano-silicon dioxide suspension and the modified multilayer graphene oxide in an ethanol solution to obtain a modified graphene composite material loaded with modified nano-silicon dioxide; The solid-liquid ratio of nano-silicon dioxide to ethanol solution in S1 is 1:40-50, the mass fraction of sodium hydroxide is 8%, and the pH value is 7-8; The solid-liquid ratio of multilayer graphene oxide to anhydrous ethanol in S2 is 1:40-50, and the pH value is 5-6; The hydrolysis reaction in S3 is to mix the modified nano-silica suspension and the modified multilayer graphene oxide with the ethanol solution, firstly perform a pre-hydrolysis reaction at 15°C-35°C for 40h-80h under acidic conditions, and then continue the hydrolysis reaction at 50-80°C for 1h-2h under alkaline conditions.

2. The shield tail lubricating grease for a shield machine according to claim 1, characterized in that: The base oil is one or more of mineral oil, vegetable oil, and synthetic oil.

3. The shield tail lubricating grease of a shield machine according to claim 1, characterized in that: The fiber material is degradable wood fiber, and the length of the fiber material is 0.1-2 mm.

4. The shield tail lubricating grease of a shield machine according to claim 1, characterized in that: The filler includes one or more of light calcium carbonate, bentonite, kaolin, mica and talc.

5. The shield tail lubricating grease of a shield machine according to claim 1, characterized in that: The viscosity promoter is one or more of polyacrylamide, N,N-dimethylacrylamide, 2-hydroxysuccinic acid, and 3-hydroxy-1,3,5-pentanetriolic acid.

6. A method for preparing a shield tail lubricating grease for a shield machine as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: (1) first adding a viscosity promoter to a base oil, stirring at room temperature until the base oil and the viscosity promoter are completely mixed, and then stopping stirring to obtain a mixture of the base oil and the viscosity promoter; (2) After adding lubricant to the mixture of base oil and viscosity promoter and continuing stirring for 1-1.5 hours, fiber material and filler are added and continuing stirring for 2-3 hours to obtain shield tail grease.

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