High-flame-retardant environment-friendly shield tunneling machine hand coating sealing grease and preparation method thereof

Abstract

The invention discloses high-flame-retardant environment-friendly shield tunneling machine hand coating sealing grease and a preparation method thereof, and relates to the technical field of sealing grease materials. The high-flame-retardant environment-friendly shield tunneling machine hand coating sealing grease is prepared from homogeneous emulsified oil, synthetic fibers, plant cellulose, mica powder, a thickening agent, a lubricating agent and calcium carbonate. The homogenized emulsified oil consists of base oil, polyisobutene, a bactericide, purified water, calcium stearate and an emulsifier, wherein the base oil is a vegetable oil mixture. Emulsified oil prepared by a special process is used as base oil and is matched with the filling powder, the thickening agent, the fibers and the lubricating agent for use, so that traditional high-viscosity hydrocarbon oil is avoided. The grease has good density, penetration, volatility, adhesion and water pressure resistance at normal temperature, has excellent flame retardant property, and ensures safe starting of the shield tunneling machine. The introduction of the emulsified oil reduces the production cost, and the vegetable oil component has biodegradability, is environment-friendly, and is beneficial to sustainable development.

Description

Technical Field

[0001] The invention relates to the technical field of sealing grease materials, and in particular to a highly flame-retardant and environment-friendly shield machine hand-coated sealing grease and a preparation method thereof. Background Art

[0002] As a machine widely used in tunnel construction, the shield tail sealing system of the shield machine plays a vital role in the entire construction process. The main function of the shield tail sealing device is to prevent groundwater, mud and other substances from penetrating into the interior of the shield machine, while avoiding corrosion and damage to mechanical equipment. Therefore, the research on the sealing grease of the shield tail of the shield machine has always been an important direction for the development of shield machine technology. Traditional hand-applied shield tail sealing grease is widely used in shield machine construction due to its good adhesion and wear resistance. This type of grease usually has good water resistance and lubrication properties, which can effectively prevent the damage to the shield machine caused by groundwater and soil, and ensure the long-term stable operation of the shield machine.

[0003] However, with the continuous improvement of shield machine technology and environmental protection requirements, traditional hand-applied shield tail sealing grease faces many challenges. The existing grease system is mainly based on high molecular polymers polymerized from polyisocyanates and hydroxyl compounds, supplemented with additives such as rust inhibitors, thickeners, and anti-fall agents to enhance its sealing performance and water shock resistance. However, these traditional grease systems have poor flame retardant properties and low flash points, and are prone to fire risks during operation, especially when manually applied in shield operation wells, which may be carried out simultaneously with other high-temperature operations (such as welding, etc.), posing safety hazards. In addition, the existing grease system may leak when in contact with groundwater and soil, and exist in the underground environment for a long time, seriously affecting the ecological environment. These shortcomings are far from the requirements of modern environmental protection laws and regulations, especially in terms of eco-friendliness and degradability, and it is difficult to meet increasingly stringent environmental protection standards.

[0004] The existing grease system not only has deficiencies in flame retardancy and environmental protection, but also has a high cost. With the gradual tightening of environmental protection regulations, especially the increasingly stringent green environmental protection requirements for grease, the applicability and market competitiveness of traditional hand-applied shield tail sealing grease have been greatly challenged. In addition, traditional grease systems often rely on high-cost raw materials and complex preparation processes, resulting in high overall costs and difficulty in meeting the needs of large-scale applications. In this context, how to reduce costs and improve environmental friendliness while ensuring sealing performance and flame retardancy has become a technical problem that needs to be solved urgently in the field of shield tail sealing grease.

[0005] At present, the research on improving shield tail sealing grease mainly focuses on enhancing the flame retardant properties and environmental friendliness of the grease. Although some studies have introduced emulsified oil systems and improved the performance of grease by adjusting the oil-in-water structure, these solutions have not been able to completely solve all the problems existing in the existing technology. Although the existing emulsified oil system has improved the flame retardant performance to a certain extent, its water-in-oil (O / W) structure still has significant performance degradation and leakage problems when facing water environments such as groundwater and mud.

[0006] In order to deal with the above problems, the present invention proposes a shield tail sealing grease based on an oil-in-water structured emulsified oil, and focuses on improving its flame retardancy, water shock resistance, pumping performance and environmental friendliness. By optimizing the structure and formula of the emulsified oil system, the grease has better environmental performance and a higher safety factor while ensuring the excellent performance of traditional grease. In particular, in solving the problems of low flame retardancy and poor environmental performance in the prior art, the technical means adopted by the present invention have important breakthrough significance, and will provide a feasible technical path for the green and environmentally friendly development of shield tail sealing grease. Summary of the invention

[0007] Aiming at the poor flame retardancy and high cost of hand-applied sealing grease at the tail of a shield machine, the present invention introduces water-in-oil structured emulsified oil into the shield tail sealing grease of the shield machine, thereby providing a hand-applied shield tail sealing grease of the shield machine with high flame retardancy, good water shock resistance and sealing performance, excellent pumpability, environmental friendliness and low cost, and a preparation method thereof.

[0008] In order to achieve the above-mentioned object of the invention, the present invention is implemented by the following technical solutions:

[0009] A highly flame-retardant and environment-friendly shield machine hand-coated sealing grease comprises, by weight, 25-35 parts of homogeneous emulsified oil, 0.5-1.5 parts of synthetic fiber, 1-2 parts of plant cellulose, 3-10 parts of mica powder, 5-10 parts of thickener, 0.5-1 part of lubricant and 30-60 parts of calcium carbonate.

[0010] Preferably, the homogenized emulsified oil comprises the following components in parts by weight: 10-20 parts of base oil, 10-20 parts of polyisobutylene, 1-2 parts of fungicide, 20-30 parts of purified water, 5-10 parts of calcium stearate, and 3-5 parts of emulsifier.

[0011] Preferably, the base oil is a mixture of soybean oil, rapeseed oil, vegetable oil or more;

[0012] Preferably, the molecular weight of the polyisobutylene is 10-50 million;

[0013] Preferably, the pure water is filtered soft water;

[0014] Preferably, the emulsifier is a Span series W / O type special emulsifier;

[0015] Preferably, the calcium stearate is calcium stearate larger than 1000 mesh;

[0016] Preferably, the bactericide is a common food bactericide.

[0017] Preferably, the plant cellulose is a mixture of one or more of wood fiber, cotton fiber, hemp fiber and bamboo fiber, and the length of the plant fiber is ≤0.5 mm.

[0018] Preferably, the synthetic fiber is a mixture of one or more of polyester fiber, nylon fiber, acrylic fiber, and polypropylene fiber, and the length of the synthetic fiber is ≤5 mm and the diameter is 10 microns to 50 microns.

[0019] Preferably, the calcium carbonate is one or more of light calcium carbonate and heavy calcium carbonate, and the size of the calcium carbonate is 400-1000 mesh.

[0020] Preferably, the mica powder is a mixed silicate powder of 300-500 mesh.

[0021] Preferably, the lubricant is a higher fatty acid ethoxylate.

[0022] Preferably, the thickener is one or more of kaolin, bentonite, chlorinated paraffin and carrageenan.

[0023] The present invention also provides a method for preparing the highly flame-retardant and environmentally friendly shield machine hand-coated sealing grease according to the above-mentioned method, which comprises adding synthetic fiber, plant cellulose, mica powder, thickener, and lubricant to homogenized emulsified oil and stirring evenly for 15-20 minutes, and then evenly adding calcium carbonate in batches during the stirring process, stirring until a uniform off-white viscous paste-like mixture is obtained.

[0024] Preferably, the preparation method of the homogeneous emulsified oil is: base oil, polyisobutylene, fungicide, purified water, calcium stearate and emulsifier are stirred at a high speed of 500-600 r / min for 30 minutes to obtain the homogeneous emulsified oil.

[0025] The technical solution provided by the present invention brings beneficial effects:

[0026] Emulsified oil produced by a special process is used as the base oil of the shield tail sealing grease, and is used in combination with filling powder, thickener, fiber, and lubricant. No traditional high-viscosity hydrocarbon oil is added to the formula, and a shield tail sealing grease product with good performance is prepared: its density is 1.5g / cm3 at 25°C, and the cone penetration (0.1mm) is 190-210 at 25°C. The volatility (80°C±1°C, 5h) is less than or equal to 1.5%. It does not flow at 50°C for 24h, and does not lose after being impacted by a water flow of 0.02MPa for 20min. The adhesion time of a normal metal plate at 25°C is greater than 60 minutes, and there is no water leakage for 10min under a water pressure of 34bar. The unique flame retardant performance of the product ensures the safety index of the shield machine at the start.

[0027] The introduction of emulsified oil has greatly reduced the production cost of shield tail sealing grease. In addition, vegetable oils are biodegradable and will not pollute the soil and groundwater, which is conducive to sustainable development. It will not cause soil pollution.

[0028] The shield tail sealing grease for hand-coated shields prepared by the present invention has excellent water pressure sealing resistance, pumping performance and lubrication performance of traditional greases. In addition, the water-in-oil (W / O) structure formed after the base oil is emulsified improves the flame retardant performance of the grease, thereby greatly improving the safety index of the project during use and storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a photo of the emulsified oil of an embodiment of the present invention;

[0030] Figure 2 This is a photo of hand-applied sealing grease for a highly flame-retardant and environment-friendly shield machine according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0032] Example 1

[0033] The components of the shield tail sealing grease are: 300kg of homogeneous emulsified oil, 10kg of PP fiber (length ≤5mm, diameter 10-50 microns), 10kg of bamboo cellulose (≤0.5mm), 40kg of 52# liquid chlorinated paraffin, 40kg of mica powder (300-500 mesh), 5kg of higher fatty acid ethoxylate, and 550kg of light calcium carbonate powder.

[0034] Preparation method: Mix the homogenized emulsified oil, bamboo cellulose, PP fiber and mica powder, stir for 10 minutes, then add 52# liquid chlorinated paraffin and higher fatty acid ethoxylates, stir for 20 minutes, add light calcium carbonate powder in 4 batches during the stirring process (add in small amounts continuously), stir for not less than 40 minutes, until a uniform off-white viscous mixture is obtained.

[0035] Preparation method of homogeneous emulsified oil: 45 kg of soybean oil, 36 kg of polyisobutylene (molecular weight of 20 million), 4.5 kg of Nafur lC1038 fungicide, 78 kg of filtered soft water, 21 kg of calcium stearate (500-1000 mesh), and 13.5 kg of Span 80 emulsifier are stirred in a 600 r / min high-speed shearing machine for 30 minutes to obtain a homogeneous emulsified oil.

[0036] Example 2

[0037] The preparation method is the same as that in Example 1, except that the components of the shield tail sealing grease are: 300 kg of homogeneous emulsified oil, 5 kg of PP fiber (length ≤ 5 mm, diameter 10 microns-50 microns), 15 kg of bamboo cellulose (≤ 0.5 mm), 50 kg of 52# liquid chlorinated paraffin, 30 kg of mica powder (300-500 mesh), 5 kg of higher fatty acid ethoxylates, and 600 kg of light calcium carbonate powder.

[0038] Example 3

[0039] The preparation method is the same as that in Example 1, except that the components of the shield tail sealing grease are: 280 kg of homogeneous emulsified oil, 7 kg of PP fiber (length ≤ 5 mm, diameter 10 microns-50 microns), 13 kg of lignocellulose (≤ 0.5 mm), 40 kg of 52# liquid chlorinated paraffin, 100 kg of mica powder (300-500 mesh), 5 kg of higher fatty acid ethoxylate, 300 kg of light calcium carbonate powder and 200 kg of heavy calcium carbonate.

[0040] Example 4

[0041] It was prepared according to the same preparation method as in Example 1, except that the components of the shield tail sealing grease were: 280 kg of homogeneous emulsified oil, 9 kg of PP fiber (length ≤ 5 mm, diameter 10 microns-50 microns), 11 kg of lignocellulose (≤ 0.5 mm), 40 kg of 52# liquid chlorinated paraffin, 30 kg of mica powder (300-500 mesh), 5 kg of higher fatty acid ethoxylate, 300 kg of light calcium carbonate powder, and 200 kg of talc.

[0042] Preparation method: Mix emulsified oil, bamboo cellulose, PP fiber and mica powder, stir for 20 minutes, then add 52# liquid chlorinated paraffin and higher fatty acid ethoxylate, stir for 20 minutes, add light calcium carbonate powder and talcum powder in 4 batches during the stirring process (add in small amounts continuously), stir for not less than 30 minutes, until a uniform off-white viscous mixture is obtained.

[0043] Example 5

[0044] It was prepared according to the same preparation method as in Example 1, except that the components of the shield tail sealing grease were: 290 kg of homogeneous emulsified oil, 8 kg of PP fiber (length ≤ 5 mm, diameter 10 microns-50 microns), 12 kg of lignocellulose (≤ 0.5 mm), 20 kg of carrageenan, 20 kg of kaolin, 30 kg of mica powder (300-500 mesh), 5 kg of higher fatty acid ethoxylates, 300 kg of light calcium carbonate powder, and 200 kg of heavy calcium carbonate.

[0045] Preparation method: Mix the emulsified oil, cellulose, PP fiber and mica powder, stir for 10 minutes, then add carrageenan, kaolin and higher fatty acid ethoxylates, stir for 20 minutes, add light calcium carbonate powder and heavy calcium carbonate in 4 batches during the stirring process (add in small amounts continuously), and stir for no less than 30 minutes until a uniform off-white viscous mixture is obtained.

[0046] Example 6

[0047] It was prepared according to the same preparation method as in Example 1, except that the components of the shield tail sealing grease were: 290 kg of homogeneous emulsified oil, 10 kg of PP fiber (length ≤ 5 mm, diameter 10 microns-50 microns), 10 kg of lignocellulose (≤ 0.5 mm), 20 kg of carrageenan, 30 kg of bentonite, 32 kg of mica powder (300-500 mesh), 5 kg of higher fatty acid ethoxylates, 300 kg of light calcium carbonate powder, and 300 kg of heavy calcium carbonate.

[0048] Preparation method: Mix the emulsified oil, cellulose, PP fiber and mica powder, stir for 10 minutes, then add carrageenan, bentonite and higher fatty acid ethoxylates, stir for 10 minutes, add light calcium carbonate powder and heavy calcium carbonate in 4 batches during the stirring process (add in small amounts continuously), and stir for no less than 30 minutes until a uniform off-white viscous mixture is obtained.

[0049] Example 7

[0050] The preparation was carried out in the same manner as in Example 6, except that in the preparation method of the homogenized emulsified oil, the base oil was rapeseed oil.

[0051] Example 8

[0052] The preparation was carried out in the same manner as in Example 6, except that in the preparation method of the homogenized emulsified oil, the base oil was a mixture of soybean oil and rapeseed oil in a mass ratio of 1:1.

[0053] Example 9

[0054] The preparation method is the same as that of Example 6, except that in the preparation method of the homogeneous emulsified oil, 10 parts of base oil and 30 parts of purified water are used.

[0055] Example 10

[0056] The preparation was carried out in the same manner as in Example 6, except that, in the preparation method of the homogenized emulsified oil, 20 parts of base oil and 20 parts of purified water were used.

[0057] Comparative Example 1

[0058] The difference from Example 6 is that the homogenized emulsified oil is replaced by paraffin oil, and other parameters remain unchanged.

[0059] Comparative Example 2

[0060] The difference from Example 6 is that the preparation method is: homogenize emulsified oil, PP fiber, bentonite, mica powder, carrageenan, bentonite, and higher fatty acid ethoxylates, stir until uniform, add light calcium carbonate powder and heavy calcium carbonate, add in small amounts continuously, stir until the filling powder is dispersed, stir evenly, add wood cellulose, and stir for not less than 30 minutes to obtain the finished product.

[0061] Experimental test:

[0062] 1. Cone penetration: refers to the depth of the cone falling into the sample under the specified load, time and temperature conditions, and its unit is 0.1mm. It is an indicator of the lubrication consistency and hardness of the beam. The larger the cone penetration value, the softer the grease, and vice versa. It refers to the depth of a certain mass of cone released from the cone penetration instrument at 25°C and the cone penetrates the sample to be tested within 5 seconds after falling.

[0063] 2. Sag value: It is an indicator of the heat resistance and rheological properties of the sealing paste. The test method is to fill the sealing paste in a metal groove with openings at both ends, place it vertically and horizontally for a period of time at a specified temperature, and measure its sagging distance. Generally, the sagging value of the sealing paste is required to be no more than 3 or 4 mm.

[0064] The performance of the shield tail sealing grease obtained in each embodiment and comparative example is shown in Table 1:

[0065] Table 1 Experimental data

[0066]

[0067]

[0068] From the results in Table 1, it can be seen that the shield tail sealing grease in Examples 1 to 10 has good sealing performance, no sagging at 50°C for 24h, no loss at 0.02MPa for 20min, long metal plate adhesion time, excellent flame retardant performance, and can meet the shield tail construction requirements. However, the corresponding parameters in Comparative Example 1 and Comparative Example 2 are reduced and cannot meet the actual shield construction requirements. This is because the ratio of the synthetic emulsified oil, plant fiber and other components in the present invention and the synergistic effect of the preparation method are achieved. For example, in Comparative Example 1, when the synthetic emulsified oil is replaced with a common base oil-paraffin oil, and no high-viscosity oil is added, the sealing performance of the shield tail sealing oil and the adhesion performance with the metal are greatly reduced; as in Comparative Example 2, even if the formula of the present invention is adopted and the original preparation method is adopted, the performance of the shield tail sealing grease prepared is not as good as the performance of the shield tail sealing grease prepared by the method of the present invention.

[0069] The environmentally friendly hand-applied shield grease prepared by the present invention is prepared by mixing and stirring a biodegradable aqueous emulsion, biodegradable fibers, inorganic fillers and various environmentally friendly additives. The grease has no harmful effects on the quality of soil and groundwater after use, and its natural degradation rate is much better than that of existing grease types. The density, cone penetration, high-pressure water sealing, water scouring resistance, evaporation loss and wear resistance have been studied, and its performance is better than that of ordinary shield grease.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A highly flame-retardant and environmentally friendly shield machine hand-applied sealing grease, characterized in that: The components include, by weight: 25-35 parts of homogenized emulsified oil, 0.5-1.5 parts of synthetic fiber, 1-2 parts of plant cellulose, 3-10 parts of mica powder, 5-10 parts of thickener, 0.5-1 part of lubricant and 30-60 parts of calcium carbonate.

2. The highly flame-retardant and environmentally friendly shield machine hand-applied sealing grease according to claim 1 is characterized in that: The homogenized emulsified oil comprises the following components in parts by weight: 10-20 parts of base oil, 10-20 parts of polyisobutylene, 1-2 parts of fungicide, 20-30 parts of purified water, 5-10 parts of calcium stearate, and 3-5 parts of emulsifier. The base oil is a mixture of one or more of soybean oil, rapeseed oil and vegetable oil; The molecular weight of the polyisobutylene is 10-50 million; The purified water is filtered soft water; The emulsifier is a Span series W / O type special emulsifier; The calcium stearate is greater than 1000 meshes; The bactericide is a common food bactericide.

3. The highly flame-retardant and environmentally friendly shield machine hand-applied sealing grease according to claim 1 is characterized in that: The plant cellulose is a mixture of one or more of wood cellulose, cotton cellulose, hemp cellulose and bamboo cellulose, and the length of the plant cellulose is ≤0.5 mm.

4. The highly flame-retardant and environmentally friendly shield machine hand-applied sealing grease according to claim 1 is characterized in that: The synthetic fiber is a mixture of one or more of polyester fiber, nylon fiber, acrylic fiber, and polypropylene fiber. The length of the synthetic fiber is ≤5 mm, and the diameter is 10 microns to 50 microns.

5. The highly flame-retardant and environmentally friendly shield machine hand-applied sealing grease according to claim 1 is characterized in that: The calcium carbonate is one or more of light calcium carbonate, heavy calcium carbonate and talcum powder, and the size of the calcium carbonate is 400-1000 mesh.

6. The highly flame-retardant and environmentally friendly shield machine hand-applied sealing grease according to claim 1 is characterized in that: The size of the mica powder is 300-500 mesh.

7. The highly flame-retardant and environmentally friendly shield machine hand-applied sealing grease according to claim 1 is characterized in that: The lubricant is a higher fatty acid ethoxylate.

8. The highly flame-retardant and environmentally friendly shield machine hand-applied sealing grease according to claim 1 is characterized in that: The thickener is one or more of kaolin, bentonite, chlorinated paraffin and carrageenan.

9. A method for preparing the highly flame-retardant and environmentally friendly shield machine hand-coated sealing grease according to any one of claims 1 to 8, characterized in that: Add synthetic fiber, plant cellulose, mica powder, thickener and lubricant to the homogenized emulsified oil and stir evenly for 15-20 minutes. Add calcium carbonate evenly in batches during the stirring process and stir to obtain a uniform off-white viscous paste-like mixture.

10. The method for preparing highly flame-retardant and environment-friendly shield machine hand-applied sealing grease according to claim 9, characterized in that: The preparation method of the homogeneous emulsified oil is as follows: base oil, polyisobutylene, bactericide, purified water, calcium stearate and emulsifier are subjected to high-speed shear stirring at 500-600 r / min for 30 minutes to obtain the homogeneous emulsified oil.

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