High-strength bolt surface treatment agent based on MXene directional arrangement and treatment process

Abstract

The invention discloses a high-strength bolt surface treatment agent based on MXene directional arrangement and a treatment process. The high-strength bolt surface treating agent is prepared by using hyperbranched polyurethane modified MXene filler and solid lubricating filler as lubricating components and using fluorocarbon resin as a bonding and fixing component. Wherein the MXene filler can be directionally arranged on the surface of the high-strength bolt under a spraying treatment process with an electric field to form a two-dimensional filler array, and the solid lubricating filler is dispersed in the array, so that the aggregation of the two-dimensional filler is effectively prevented, and the dispersion lubricating performance of the solid lubricating filler in a system is enhanced; and the uniformity of the torque coefficient of the bolt after surface treatment is improved. The treatment process shows more stable friction performance and weather resistance to the external environment under different environment temperature and humidity conditions. The surface treatment agent and the treatment process have excellent use performance, and are of great significance to related technical progress and industrial development.

Description

Technical Field

[0002] The present invention belongs to the technical field of fine polymer materials and metal surface treatment, and specifically relates to the preparation of a high-strength bolt surface treatment agent based on MXene directional arrangement and its application in the fields of construction, industrial storage tanks, transportation infrastructure, small components, wind power main agent, etc. for bolt connection secondary surface treatment. Background Art

[0004] The use of high-strength bolts for steel structure connection has the advantages of simple construction, good force performance, removable and replaceable, and fatigue resistance. It has been widely used in steel structure projects such as buildings, bridges, and large machinery at home and abroad. The connection quality of high-strength bolt connections is directly related to the overall stability and safety of the steel structure and must be strictly controlled. Among them, the axial pretension when the bolt is tightened has a direct impact on the connection quality of the bolt pair. It must be controlled within a certain range. Too high or too low will cause safety hazards. In the most widely used torque method bolt connection construction, construction personnel use torque wrenches to determine the tightening torque when tightening the bolts to carry out construction, but the pretension value cannot be directly obtained in this process. Therefore, the correspondence between the tightening torque and the pretension is very important. Under the condition of a certain nominal diameter of the thread, the torque coefficient is the key to controlling the pretension through the construction torque. Due to different production quality, connection methods and surface friction conditions, the torque coefficient value of high-strength bolts generally varies in the range of 0.1~0.45. In order to better control the bolt pretension during construction, it is essential to strictly control the torque coefficient parameters of high-strength bolt connections.

[0005] The control of friction and lubrication properties on the bolt surface is the key to controlling the stability of the torque coefficient of high-strength bolted connections. In order to make the torque coefficient meet the standard requirements, special surface lubrication treatment is required for high-strength bolted connections. Commonly used methods include post-processing technologies in the form of phosphorus saponification treatment, polymer latex film, semi-solid polymer film, galvanized layer, etc., which can effectively ensure that the torque coefficient of the same batch of high-strength bolted connections can be controlled within a smaller range that meets the standards. For example, patent CN109554652B discloses a bolt surface treatment process, which improves the effect of bolt electrogalvanizing surface treatment by ultrasonic cleaning, nitrogen environment heating and other methods. Patent CN115584156B discloses a bolt connection surface anti-corrosion lubrication coating material and preparation method, which combines surface anti-corrosion treatment and lubrication by layered impregnation of zinc-aluminum powder coating and MoS2 lubricating liquid. Patent CN116921182B discloses a method for processing the torque coefficient of chromium-free anti-corrosion high-strength bolts. By sequentially coating an anti-corrosion coating and a composite grease on the surface of the bolt, a high-strength bolt with high weather resistance, wear resistance and corrosion resistance is prepared while having a relatively stable torque coefficient.

[0006] From the above description, it can be seen that the surface treatment methods of high-strength bolt connection pairs that have been studied have good practical value. However, from the perspective of overall technical development, the surface treatment methods of high-strength bolt connection pairs still face some problems. The most significant problem is that the torque coefficient of the treated bolts will also change with the changes in ambient temperature and humidity. For example, the torque coefficient of the bolts treated with phosphorus saponification will generally change by 6%~7% with every 10°C change in temperature. Therefore, when facing an environment with a large temperature difference and humidity difference, the torque coefficient is also difficult to guarantee, and the torque coefficient needs to be measured at different temperatures, which affects the construction efficiency and economic cost. Secondly, because the determination of the torque coefficient usually consumes a large number of bolts, the torque coefficient of the bolt cannot be guaranteed after the bolt is tightened once under the traditional treatment process, resulting in a lot of waste. Therefore, based on relevant research, further developing new high-strength bolt surface treatment agents and treatment processes, further improving the uniformity of the torque coefficient of high-strength bolts after surface treatment, reducing the sensitivity of the torque coefficient to ambient temperature and humidity, and improving the torque stability under two or more tightening conditions are of great significance for promoting the further development of related technologies, improving the construction efficiency of building steel structures, reducing construction costs, and promoting industry progress. Summary of the invention

[0008] The purpose of the present invention is to solve the above problems and provide a high-strength bolt surface treatment agent and treatment process based on MXene directional arrangement.

[0009] The high-strength bolt surface treatment agent based on MXene directional arrangement described in the present invention is a suspension dispersion composed of a two-dimensional MXene filler, a solid lubricating filler, a bonding agent, a solvent and an additive; wherein the two-dimensional MXene filler is a two-dimensional MXene filler whose surface is modified by hyperbranched polyurethane; wherein the size of the solid lubricating filler is 1 μm ~3 μm; wherein the bonding agent is a mixture of a fluorocarbon resin and a latent curing agent; and the mass ratio of the two-dimensional MXene filler, the solid lubricating filler, the bonding agent, the solvent and the additive is 1: (3.5~5): (5.4~7.2): (10~15): (0.05~0.3).

[0010] The two-dimensional MXene filler in the high-strength bolt surface treatment agent is at least one of Ti3C2, Ta4C3, Mo2C, NbC, V2C, and Ti3CN, which are prepared by chemical etching using the corresponding MAX phase, and the number of layers is 4 to 10; the hyperbranched polyurethane is a hyperbranched polyurethane molecule with a large number of terminal amine groups obtained by reacting diisocyanate and trifunctional polyol in dimethylformamide at a molar ratio of 2.1:1 and a concentration of 5%, and then adding diethylenetriamine for end-capping; wherein the diisocyanate is at least one of toluene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate, and the polyol is at least one of tripolyether polyol, tripolyester polyol and trimethylolmethane; the branching degree of the hyperbranched polyurethane is 0.4 to 0.8, and the number average molecular weight is 6000 to 8000 Da.

[0011] The solid lubricating filler in the high-strength bolt surface treatment agent is at least one of CaF2, MoS2, graphite, boron nitride, and PTFE; the fluorocarbon resin in the adhesive fixative is at least one of water-based or solvent-based polyvinylidene fluoride resin, polytrifluorochloroethylene-vinyl ether resin, and polytetrafluorochloroethylene-vinyl ether resin; the latent curing agent is a low-temperature blocked isocyanate curing agent; and the mass ratio of the fluorocarbon resin to the latent curing agent is 1:(0.15~0.32).

[0012] The solvent in the high-strength bolt surface treatment agent is at least one of water, methanol, ethanol, formic acid, and benzyl alcohol; the auxiliary agent is at least one of a dispersant, a defoamer, a leveling agent, and a rheology regulator, and the rheology regulator is at least one of bentonite, hydrated magnesium silicate, fumed silica, and polymer wax.

[0013] The preparation method of the high-strength bolt surface treatment agent is as follows:

[0014] (1) Modification of two-dimensional MXene filler: soak the two-dimensional MXene filler in a modification solution containing a double-bond silane coupling agent at room temperature for 18 hours, and then place the silane-modified two-dimensional filler into the prepared hyperbranched polyurethane solution for reaction for 24 hours to obtain a hyperbranched polyurethane-modified two-dimensional MXene filler; wherein the modification solution is composed of 90% alcohol solvent, 9% ammonia water and 1% double-bond silane coupling agent, the alcohol solvent is at least one of methanol, ethanol, isopropanol and n-butanol, and the double-bond silane coupling agent is at least one of methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and vinyltrimethoxyethoxysilane.

[0015] (2) Slurry dispersion: Weigh appropriate amounts of each component, use a high-speed disperser to disperse and mix the two-dimensional MXene filler with part of the adhesive and solvent at 3-5 m / s for 20 min, and then perform ultrasonic treatment for 6-8 min to obtain mixture A; stir the solid lubricating filler, additive and the remaining part of the adhesive and solvent at room temperature and disperse them in a ball mill for 4 h to obtain mixture B; add mixture A to mixture B at a linear speed of 6-10 m / s and disperse for 5-10 min until the system is uniform and stable to obtain a high-strength bolt surface treatment agent.

[0016] The surface treatment process of high-strength bolts based on the high-strength bolt surface treatment agent is as follows: (1) Cleaning: Use hot water at 60~70℃ to prepare a hot solution containing a surfactant cleaning agent, and adjust the pH value of the solution to 9~10. Place the bolt in the hot solution and use ultrasonic cleaning for 30 minutes, then rinse the surface solution with warm water and dry it at room temperature; (2) Spraying: Use a high-performance electrostatic spray machine to evenly spray the surface treatment agent on the surface of the high-strength bolt; (3) Curing: Put the sprayed bolt in an oven to dry and cure for 2 h~3 h to obtain a surface-treated high-strength bolt with a stable torque coefficient. The spray thickness of the surface treatment agent is 10 μm~20 μm, and the curing temperature of the surface treatment agent is 80℃~120℃.

[0017] The positive effects of the high-strength bolt surface treatment agent based on MXene directional arrangement of the present invention are:

[0018] In the high-strength bolt surface treatment agent of the present invention, a two-dimensional MXene filler with rich amino groups on the surface is introduced and dispersed together with a conventional solid lubricating filler. Since the two-dimensional few-layer MXene filler is a layered structure similar to an accordion, the weak van der Waals force between the layers has a higher tribochemical activity. The contact surface and collision probability of the two-dimensional MXene filler in common friction with the solid lubricating filler are greater, resulting in a better synergistic friction effect. In addition, since the system uses a proton solvent, the two-dimensional MXene filler with rich amino groups on the surface will generate positive charges therein, and it can be effectively arranged in a directional manner in the electric field of electrostatic spraying to form a two-dimensional MXene filler array, which can effectively prevent the aggregation of the two-dimensional filler, and effectively enhance the dispersion and lubrication properties of the solid lubricating filler in the entire system, improve the uniformity of the torque coefficient of the bolt after surface treatment, and reduce the thickness of the surface modified layer and the amount of lubricant. In addition, the formation of a regular array effectively reduces the friction damage of the surface modified layer during the bolt tightening process, which also enables the high-strength bolt to have a certain repeated tightening performance, which can effectively reduce the bolt loss during the test process.

[0019] In addition, since fluorocarbon resin is used as a bonding agent in the system, the addition of high-fluorine-containing materials makes it show more stable surface lubrication performance under different ambient temperature and humidity conditions, and also significantly enhances the system's weather resistance to the external environment. In addition, the rich amino groups on the surface of the two-dimensional MXene filler can effectively react with the blocked isocyanate curing agent during the high-temperature curing process, so that the two-dimensional filler has a more beneficial bonding performance with the bonding and fixing substrate. Therefore, it has a better sealing function and has a better effect on the corrosion protection of the substrate. The effectiveness time of the bolts after surface treatment is significantly increased.

[0020] From the above description, it can be seen that the high-strength bolt surface treatment agent technology has a clear mechanism of action, a simple production process, excellent product performance, strong durability, low cost, and is suitable for large-scale production applications. It is of great significance for the preparation, research and development of bolt connection sub-surface treatment materials with low environmental temperature and humidity sensitivity and their promotion in related application fields. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to specific embodiments.

[0023] Example 1: A high-strength bolt surface treatment agent I based on MXene directional arrangement and its treatment process:

[0024] (1) The few-layer two-dimensional Ti3CN filler was immersed in a modification solution containing a double-bond silane coupling agent at room temperature for 18 h, and then the modified Ti3CN filler was placed in a terminal amine hyperbranched polyurethane solution with a branching degree of 0.6 and a molecular weight of 7000 prepared by using TDI and a trifunctional polyether polyol with a molecular weight of 500 and reacted for 24 h to obtain a hyperbranched macromolecular modified two-dimensional Ti3CN filler T1;

[0025] (2) After mixing 1 part of two-dimensional Ti3CN filler T1 with 3 parts of a bonding agent composed of solvent-based polytrifluorochloroethylene-vinyl ether resin and solvent-based low-temperature blocked isocyanate and 5 parts of ethanol, the mixture was dispersed and mixed in a high-speed disperser at 5 m / s for 20 min, followed by ultrasonic treatment for 8 min to obtain a mixture A1; 3.8 parts of PTFE micropowder, 0.05 parts of dispersant, 0.05 parts of defoaming agent, 3.2 parts of bonding agent and 8.2 parts of ethanol were stirred evenly at room temperature and then ground and dispersed in a ball mill for 4 h to obtain a mixture B1; the A1 mixture was added to the B1 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent I.

[0026] (3) The bolts were placed in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and cleaned using ultrasound for 30 min. The surface solution was rinsed with warm water and then dried. A high-performance electrostatic spray machine was then used to evenly spray the surface treatment agent I onto the surface of the high-strength bolts. The spray layer thickness was 15 μm. The sprayed bolts were placed in an oven at a temperature of 80°C for drying and curing for 2 h to obtain surface-treated high-strength bolts with a stable torque coefficient.

[0027] Example 2: A high-strength bolt surface treatment agent II based on MXene directional arrangement and its treatment process:

[0028] (1) The few-layer two-dimensional Ti3C2 filler was immersed in a modification solution containing a double-bond silane coupling agent at room temperature for 18 h, and then the modified Ti3C2 filler was placed in a terminal amine-group hyperbranched polyurethane solution with a branching degree of 0.7 and a molecular weight of 6500 prepared by using IPDI and a trifunctional polyester polyol with a molecular weight of 600 and reacted for 24 h to obtain a hyperbranched macromolecular modified two-dimensional Ti3C2 filler T2;

[0029] (2) After mixing 1 part of two-dimensional Ti3C2 filler T2 with 3 parts of adhesive and fixing agent composed of water-based polyvinylidene fluoride resin and water-based low-temperature blocked isocyanate and 5 parts of water, the mixture was dispersed and mixed in a high-speed disperser at 5 m / s for 20 min, and then ultrasonically treated for 6 min to obtain an A2 mixture; 4.2 parts of MoS2 micropowder, 0.05 parts of leveling agent, 0.05 parts of defoaming agent, 0.1 parts of thixotropic agent, 4.05 parts of adhesive and fixing agent and 7.5 parts of water were stirred evenly at room temperature and then ground and dispersed in a ball mill for 4 h to obtain a B2 mixture; the A2 mixture was added to the B2 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent II.

[0030] (3) Place the bolt in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and use ultrasonic cleaning for 30 min. Rinse the surface solution with warm water and dry it. Then use a high-performance electrostatic spray machine to evenly spray the surface treatment agent II onto the surface of the high-strength bolt with a spray layer thickness of 15 μm. Place the sprayed bolt in an oven at a temperature of 110°C and dry and cure it for 2 h to obtain a surface-treated high-strength bolt with a stable torque coefficient.

[0031] Example 3: A high-strength bolt surface treatment agent III based on MXene directional arrangement and its treatment process:

[0032] (1) The few-layer two-dimensional NbC filler was immersed in a modification solution containing a double-bond silane coupling agent at room temperature for 18 h, and then the modified NbC filler was placed in a terminal amine hyperbranched polyurethane solution with a branching degree of 0.5 and a molecular weight of 6300 prepared by using HDI and a ternary polycaprolactone polyol with a molecular weight of 700 and reacted for 24 h to obtain a hyperbranched macromolecular modified two-dimensional NbC filler T3;

[0033] (2) After 1 part of two-dimensional NbC filler T3 was mixed with 3 parts of a bonding agent composed of solvent-based polytetrafluoroethylene-vinyl ether resin and solvent-based low-temperature blocked isocyanate and 5 parts of methanol, the mixture was dispersed and mixed at 5 m / s for 20 min using a high-speed disperser, followed by ultrasonic treatment for 6 min to obtain a mixture A3; 4.5 parts of graphite powder, 0.05 parts of dispersant, 0.05 parts of thixotropic agent, 3.15 parts of bonding agent and 9 parts of methanol were stirred evenly at room temperature and then ground and dispersed in a ball mill for 4 h to obtain a mixture B3; the A3 mixture was added to the B3 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent III.

[0034] (3) Place the bolt in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and use ultrasonic cleaning for 30 min. Rinse the surface solution with warm water and dry it. Then use a high-performance electrostatic spray machine to evenly spray the surface treatment agent III onto the surface of the high-strength bolt with a spray layer thickness of 18 μm. Place the sprayed bolt in an oven at a temperature of 90°C and dry and cure it for 2 h to obtain a surface-treated high-strength bolt with a stable torque coefficient.

[0035] Example 4: A high-strength bolt surface treatment agent IV based on MXene directional arrangement and its treatment process:

[0036] (1) The few-layer two-dimensional Ta4C3 filler was immersed in a modification solution containing a double-bond silane coupling agent at room temperature for 18 h, and then the modified Ta4C3 filler was placed in a terminal amine hyperbranched polyurethane solution with a branching degree of 0.6 and a molecular weight of 7500 prepared by using TDI and a terpolymer polyol with a molecular weight of 500 for 24 h to obtain a hyperbranched macromolecular modified two-dimensional Ta4C3 filler T4;

[0037] (2) After mixing 1 part of two-dimensional Ta4C3 filler T4 with 3 parts of adhesive and fixing agent composed of water-based polytrifluorochloroethylene-vinyl ether resin and water-based low-temperature blocked isocyanate and 5 parts of water, the mixture was dispersed and mixed using a high-speed disperser at 5 m / s for 20 min, and then ultrasonically treated for 6 min to obtain an A4 mixture; 4 parts of PTFE micropowder, 0.05 parts of dispersant, 0.05 parts of leveling agent, 0.05 parts of defoaming agent, 3.8 parts of adhesive and fixing agent and 7 parts of water were stirred evenly at room temperature and then ground and dispersed using a ball mill for 4 h to obtain a B4 mixture; the A4 mixture was added to the B4 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent IV.

[0038] (3) Place the bolt in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and use ultrasonic cleaning for 30 min. Rinse the surface solution with warm water and dry it. Then use a high-performance electrostatic spray machine to evenly spray the surface treatment agent IV onto the surface of the high-strength bolt with a spray layer thickness of 15 μm. Place the sprayed bolt in an oven at a temperature of 105°C and dry and cure it for 2 h to obtain a surface-treated high-strength bolt with a stable torque coefficient.

[0039] Example 5: A high-strength bolt surface treatment agent V based on MXene directional arrangement and its treatment process:

[0040] (1) The few-layer two-dimensional V2C filler was immersed in a modification solution containing a double-bond silane coupling agent at room temperature for 18 h, and then the modified V2C filler was placed in a terminal amine hyperbranched polyurethane solution with a branching degree of 0.6 and a molecular weight of 7000 prepared by using IPDI and a ternary polyether polyol with a molecular weight of 700 for 24 h to obtain a hyperbranched macromolecular modified two-dimensional V2C filler T5;

[0041] (2) After mixing 1 part of two-dimensional V2C filler T5 with 3 parts of adhesive and fixing agent composed of solvent-based polyvinylidene fluoride resin and solvent-based low-temperature blocked isocyanate and 5 parts of benzyl alcohol, the mixture was dispersed and mixed at 5 m / s for 20 min using a high-speed disperser, followed by ultrasonic treatment for 6 min to obtain an A5 mixture; 4.8 parts of boron nitride powder, 0.05 parts of leveling agent, 0.05 parts of defoaming agent, 3.7 parts of adhesive and fixing agent and 8.5 parts of benzyl alcohol were stirred evenly at room temperature and then ground and dispersed in a ball mill for 4 h to obtain a B5 mixture; the A5 mixture was added to the B5 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent V.

[0042] (3) Place the bolt in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and use ultrasonic cleaning for 30 min. Rinse the surface solution with warm water and dry it. Then use a high-performance electrostatic spray machine to evenly spray the surface treatment agent V onto the surface of the high-strength bolt with a spray layer thickness of 15 μm. Place the sprayed bolt in an oven at a temperature of 105°C and dry and cure it for 2 h to obtain a surface-treated high-strength bolt with a stable torque coefficient.

[0043] Example 6: A high-strength bolt surface treatment agent VI based on MXene directional arrangement and its treatment process:

[0044] (1) The few-layer two-dimensional Ti3C2 filler was immersed in a modification solution containing a double-bond silane coupling agent at room temperature for 18 h, and then the modified Ti3C2 filler was placed in a terminal amine-group hyperbranched polyurethane solution with a branching degree of 0.5 and a molecular weight of 6500 prepared by using HDI and a trifunctional polyether polyol with a molecular weight of 600 for 24 h to obtain a hyperbranched macromolecular modified two-dimensional Ti3C2 filler T6;

[0045] (2) After mixing 1 part of two-dimensional Ti3C2 filler T6 with 3 parts of adhesive and fixing agent composed of water-based polytrifluorochloroethylene-vinyl ether resin and water-based low-temperature blocked isocyanate and 5 parts of water, the mixture was dispersed and mixed in a high-speed disperser at 5 m / s for 20 min, and then ultrasonically treated for 6 min to obtain an A6 mixture; 4.2 parts of MoS2 micropowder, 0.05 parts of defoaming agent, 0.1 parts of thixotropic agent, 3.4 parts of adhesive and fixing agent and 9.7 parts of water were stirred evenly at room temperature and then ground and dispersed in a ball mill for 4 h to obtain a B6 mixture; the A6 mixture was added to the B6 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent VI.

[0046] (3) Place the bolt in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and use ultrasonic cleaning for 30 min. Rinse the surface solution with warm water and dry it. Then use a high-performance electrostatic spray machine to evenly spray the surface treatment agent VI onto the surface of the high-strength bolt with a spray layer thickness of 18 μm. Place the sprayed bolt in an oven at a temperature of 110°C and dry and cure it for 2 h to obtain a surface-treated high-strength bolt with a stable torque coefficient.

[0047] Example 7: A high-strength bolt surface treatment agent VII based on MXene directional arrangement and its treatment process:

[0048] (1) The few-layer two-dimensional Mo2C filler was immersed in a modification solution containing a double-bond silane coupling agent at room temperature for 18 h, and then the modified Mo2C filler was placed in a terminal amine hyperbranched polyurethane solution with a branching degree of 0.7 and a molecular weight of 7500 prepared by using TDI and a trifunctional polyether polyol with a molecular weight of 500 and reacted for 24 h to obtain a hyperbranched macromolecular modified two-dimensional Mo2C filler T7;

[0049] (2) After mixing 1 part of two-dimensional Mo2C filler T7 with 3 parts of adhesive and fixing agent composed of water-based polytetrafluoroethylene-vinyl ether resin and water-based low-temperature blocked isocyanate and 5 parts of water, the mixture was dispersed and mixed in a high-speed disperser at 5 m / s for 20 min, and then ultrasonically treated for 6 min to obtain an A7 mixture; 4.5 parts of CaF2 micropowder, 0.05 parts of leveling agent, 0.05 parts of dispersant, 4 parts of adhesive and fixing agent and 8 parts of water were stirred evenly at room temperature and then ground and dispersed in a ball mill for 4 h to obtain a B7 mixture; the A7 mixture was added to the B7 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent VII.

[0050] (3) Place the bolt in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and use ultrasonic cleaning for 30 min. Rinse the surface solution with warm water and dry it. Then use a high-performance electrostatic spray machine to evenly spray the surface treatment agent VII onto the surface of the high-strength bolt with a spray layer thickness of 15 μm. Place the sprayed bolt in an oven at a temperature of 110°C and dry and cure it for 2 h to obtain a surface-treated high-strength bolt with a stable torque coefficient.

[0051] Example 8: A high-strength bolt surface treatment agent VIII based on MXene directional arrangement and its treatment process:

[0052] (1) The few-layer two-dimensional Ti3C2 filler was immersed in a modification solution containing a double-bond silane coupling agent at room temperature for 18 h, and then the modified Ti3C2 filler was placed in a terminal amine hyperbranched polyurethane solution with a branching degree of 0.6 and a molecular weight of 7000 prepared by using IPDI and a trifunctional polyether polyol with a molecular weight of 600 for 24 h to obtain a hyperbranched macromolecular modified two-dimensional Ti3C2 filler T8;

[0053] (2) After mixing 1 part of two-dimensional Ti3C2 filler T8 with 3 parts of an adhesive consisting of a solvent-based polyvinylidene fluoride resin and a solvent-based low-temperature blocked isocyanate and 5 parts of ethanol, the mixture was dispersed and mixed using a high-speed disperser at 5 m / s for 20 min, and then ultrasonically treated for 6 min to obtain an A8 mixture; 4.3 parts of PTFE micropowder, 0.05 parts of a dispersant, 0.05 parts of a defoaming agent, 0.05 parts of a leveling agent, 3.4 parts of an adhesive and a fixative and 6 parts of ethanol were stirred evenly at room temperature and then ground and dispersed using a ball mill for 4 h to obtain a B8 mixture; the A8 mixture was added to the B8 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent VIII.

[0054] (3) Place the bolt in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and use ultrasonic cleaning for 30 min. Rinse the surface solution with warm water and dry it. Then use a high-performance electrostatic spray machine to evenly spray the surface treatment agent VIII onto the surface of the high-strength bolt with a spray layer thickness of 15 μm. Place the sprayed bolt in an oven at a temperature of 85°C and dry and cure it for 2 h to obtain a surface-treated high-strength bolt with a stable torque coefficient.

[0055] Comparative Example 1: Conventional phosphorus saponification treatment of high-strength bolts

[0056] A certain brand of high-strength bolts currently on the market that have been treated with phosphorus saponification were taken and their performance was compared with that of the example.

[0057] Comparative Example 2: High-strength bolts treated with commercially available solid lubricants

[0058] A commercially available solid dry film lubricant of a certain brand was used as a surface treatment agent to perform surface immersion treatment on high-strength bolts and then compared with the example.

[0059] Comparative Example 3: Surface treatment agent IX prepared from pure solid lubricating micropowder and its treatment process.

[0060] (1) 5.2 parts of MoS2 powder, 0.05 parts of leveling agent, 0.05 parts of defoaming agent, 0.1 parts of thixotropic agent, 7.05 parts of adhesive fixing agent composed of water-based polyvinylidene fluoride resin and water-based low-temperature blocked isocyanate, and 12.5 parts of water were stirred evenly at room temperature and then ground and dispersed in a ball mill for 4 h to obtain high-strength bolt surface treatment agent IX.

[0061] (2) Place the bolt in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and use ultrasonic cleaning for 30 min. Rinse the surface solution with warm water and dry it. Then use a high-performance electrostatic spray machine to evenly spray the surface treatment agent IX onto the surface of the high-strength bolt with a spray layer thickness of 15 μm. Place the sprayed bolt in an oven at a temperature of 110°C and dry and cure it for 2 h to obtain a surface-treated high-strength bolt with a stable torque coefficient.

[0062] Comparative Example 4: Surface treatment agent X prepared from pure Mxene filler and its treatment process.

[0063] (1) 5.2 parts of two-dimensional Ti3C2 filler T2, 0.05 parts of leveling agent, 0.05 parts of defoaming agent, 0.1 parts of thixotropic agent, 7.05 parts of adhesive fixing agent composed of water-based polyvinylidene fluoride resin and water-based low-temperature blocked isocyanate, and 12.5 parts of water were mixed, dispersed and mixed in a high-speed disperser at 5 m / s for 20 min, and then ultrasonically treated for 6 min to obtain a high-strength bolt surface treatment agent X.

[0064] (2) The bolts were placed in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and ultrasonically cleaned for 30 min. The surface solution was rinsed with warm water and dried. The surface treatment agent X was then sprayed evenly onto the surface of the high-strength bolt using a high-performance electrostatic spray machine. The spray layer thickness was 15 μm. The sprayed bolts were placed in an oven at a temperature of 110°C for drying and curing for 2 h to obtain surface-treated high-strength bolts with a stable torque coefficient.

[0065] Comparative Example 5: Surface treatment agent XI prepared from unmodified Mxene filler and its treatment process.

[0066] (1) 1 part of unmodified hyperbranched polyurethane few-layer two-dimensional Ti3C2 was mixed with 3 parts of a bonding agent composed of solvent-based polyvinylidene fluoride resin and solvent-based low-temperature blocked isocyanate and 5 parts of ethanol, and the mixture was dispersed and mixed in a high-speed disperser at 5 m / s for 20 min, followed by ultrasonic treatment for 6 min to obtain an A9 mixture; 4.3 parts of PTFE micropowder, 0.05 parts of dispersant, 0.05 parts of defoaming agent, 0.05 parts of leveling agent, 3.4 parts of bonding agent and 6 parts of ethanol were stirred evenly at room temperature and then ground and dispersed in a ball mill for 4 h to obtain a B9 mixture; the A9 mixture was added to the B9 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent XI.

[0067] (2) The bolts were placed in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and cleaned using ultrasound for 30 min. The surface solution was rinsed with warm water and then dried. A high-performance electrostatic spray machine was then used to evenly spray the surface treatment agent XI onto the surface of the high-strength bolts with a spray layer thickness of 15 μm. The sprayed bolts were placed in an oven at a temperature of 85°C for drying and curing for 2 h to obtain surface-treated high-strength bolts with a stable torque coefficient.

[0068] Comparative Example 6: High-strength bolt surface treatment agent and treatment process using conventional surface treatment methods.

[0069] (1) Place the bolt in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and use ultrasonic cleaning for 30 min. Rinse the surface solution with warm water and dry it. Then use an air spray gun to evenly spray the surface treatment agent VII on the surface of the high-strength bolt with a spray layer thickness of 15 μm. Place the sprayed bolt in an oven at a temperature of 110°C and dry and cure it for 2 h to obtain a surface-treated high-strength bolt with a stable torque coefficient.

[0070] Comparative Example 7: Surface treatment agent XII prepared using large-size solid lubricant filler and its treatment process.

[0071] (1) One part of two-dimensional NbC filler T3 was mixed with 3 parts of a bonding agent composed of solvent-based polytetrafluoroethylene-vinyl ether resin and solvent-based low-temperature blocked isocyanate and 5 parts of methanol, and the mixture was dispersed and mixed at 5 m / s for 20 min using a high-speed disperser, followed by ultrasonic treatment for 6 min to obtain an A10 mixture. 4.5 parts of 20 μm graphite powder, 0.05 parts of a dispersant, 0.05 parts of a thixotropic agent, 3.15 parts of a bonding agent and 9 parts of methanol were stirred evenly at room temperature and then ground and dispersed in a ball mill for 4 h to obtain a B10 mixture. The A10 mixture was added to the B10 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent XII.

[0072] (2) Place the bolt in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and use ultrasonic cleaning for 30 min. Rinse the surface solution with warm water and dry it. Then use a high-performance electrostatic spray machine to evenly spray the surface treatment agent XII onto the surface of the high-strength bolt with a spray layer thickness of 18 μm. Place the sprayed bolt in an oven at a temperature of 90°C and dry and cure it for 2 h to obtain a surface-treated high-strength bolt with a stable torque coefficient.

[0073] Comparative Example 8: Surface treatment agent XIII prepared using polyurethane resin as a bonding and fixing agent and its treatment process.

[0074] (1) After 1 part of two-dimensional Ta4C3 filler T4 was mixed with 3 parts of an adhesive consisting of a waterborne polyurethane resin and a waterborne low-temperature blocked isocyanate and 5 parts of water, the mixture was dispersed and mixed at 5 m / s for 20 min using a high-speed disperser, followed by ultrasonic treatment for 6 min to obtain an A11 mixture; 4 parts of PTFE micropowder, 0.05 parts of a dispersant, 0.05 parts of a leveling agent, 0.05 parts of a defoaming agent, 3.8 parts of an adhesive and a fixative and 7 parts of water were stirred uniformly at room temperature and then ground and dispersed in a ball mill for 4 h to obtain a B11 mixture; the A11 mixture was added to the B11 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent XIII.

[0075] (2) The bolts were placed in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and cleaned using ultrasound for 30 min. The surface solution was rinsed with warm water and dried. The surface treatment agent XIII was then sprayed evenly onto the surface of the high-strength bolt using a high-performance electrostatic spray machine with a spray layer thickness of 15 μm. The sprayed bolts were placed in an oven at a temperature of 105°C and dried and cured for 2 h to obtain surface-treated high-strength bolts with a stable torque coefficient.

[0076] Comparative Example 9: High-strength bolt surface treatment agent XIV with very few layers of MXene oriented and its treatment process:

[0077] (1) A two-dimensional Ti3C2 filler with very few layers (mainly single and double layers) was immersed in a modification solution containing a double-bond silane coupling agent at room temperature for 18 h, and then the modified Ti3C2 filler was placed in a terminal amine-group hyperbranched polyurethane solution with a branching degree of 0.5 and a molecular weight of 6500 prepared by using HDI and a trifunctional polyether polyol with a molecular weight of 600 and reacted for 24 h to obtain a hyperbranched macromolecular modified two-dimensional Ti3C2 filler T9;

[0078] (2) After mixing 1 part of two-dimensional Ti3C2 filler T6 with 3 parts of an adhesive consisting of water-based polytrifluorochloroethylene-vinyl ether resin and water-based low-temperature blocked isocyanate and 5 parts of water, the mixture was dispersed and mixed in a high-speed disperser at 5 m / s for 20 min, followed by ultrasonic treatment for 6 min to obtain an A12 mixture; 4.2 parts of MoS2 micropowder, 0.05 parts of a defoaming agent, 0.1 parts of a thixotropic agent, 3.4 parts of an adhesive and a fixing agent and 9.7 parts of water were stirred evenly at room temperature and then ground and dispersed in a ball mill for 4 h to obtain a B12 mixture; the A12 mixture was added to the B12 mixture at a linear speed of 8 m / s and dispersed for 10 min until the system was uniform and stable to obtain a high-strength bolt surface treatment agent XIV.

[0079] (3) The bolts were placed in a hot solution containing a surfactant detergent at a pH of 9-10 and a temperature of 60-70°C and cleaned using ultrasound for 30 min. The surface solution was rinsed with warm water and dried. A high-performance electrostatic spray machine was then used to evenly spray the surface treatment agent XIV onto the surface of the high-strength bolts. The spray layer thickness was 18 μm. The sprayed bolts were placed in an oven at a temperature of 110°C for drying and curing for 2 h to obtain surface-treated high-strength bolts with a stable torque coefficient.

[0080] Effect description:

[0081] The high-strength bolt surface treatment agent based on MXene directional arrangement prepared in Examples 1-8 of the present invention and its treatment process were used to perform surface treatment modification on high-strength bolts and the performance test was compared with the comparative bolts of Comparative Examples 1-9. The torque coefficient of the bolts at different temperatures was tested. The test standard was based on GB / T 1231-2024 "High-strength large hexagonal bolt connection for steel structure". The tightening speed was 8 rpm. The test results were expressed as the average value and standard deviation of the torque coefficient. Eight parallel specimens were made for each group of samples. The test results are shown in Table 1.

[0082] Table 1 Test results of torque coefficient of high strength bolts

[0083]

[0084] From the data in Table 1, it can be seen that the high-strength bolt surface treatment agent based on MXene directional arrangement prepared by the embodiment of this patent and its treatment process can control the torque coefficient of the bolt within a very stable range, and the torque coefficient test results of the bolt in high and low temperature environments can be maintained at a level close to the room temperature test results, which effectively ensures the stability of high-strength bolts in on-site construction in an environment with large changes in ambient temperature, and greatly improves the durability and safety of bolted components. The test results confirm that the embodiments of the present invention have strong practical value.

[0085] In contrast, it can be seen that comparative example 1 uses the commonly used phosphorus saponification method to treat the bolt surface. Although it also has good effects under normal temperature conditions, its torque coefficient increases rapidly with the decrease of ambient temperature, reaching 0.185 at -20°C, which exceeds the specified torque coefficient range. Therefore, this causes a great obstacle to its bolt construction in different environments. Although the commercially available solid dry film lubricant used in comparative example 2 can slightly reduce the stability sensitivity of the torque coefficient, its overall friction performance is still insufficient, so its overall torque is relatively large and exceeds the specified range at low temperatures.

[0086] In Comparative Example 3, pure solid lubricant components were used for surface treatment. Although solid lubricants and fluorocarbon resin components were also used, the lubrication performance was also insufficient due to the lack of the two-dimensional filler component, and the performance was only slightly higher than that of commercially available solid dry film lubricants. In Comparative Example 4, a surface modifier prepared from pure modified MXene two-dimensional fillers was used for treatment. It can be seen that due to the introduction of a large number of directional two-dimensional fillers, its lubrication performance exceeded the requirements, the torque coefficient was lower than the standard requirements, and due to the lack of a large number of stable solid lubricating fillers, its temperature stability was also lower than that of the embodiment, so the performance was not suitable.

[0087] For Comparative Examples 5 and 6, since two-dimensional fillers with unmodified surface amino groups are used or spraying is not performed under electric field conditions, the directional arrangement tendency of the two-dimensional fillers is greatly reduced compared to the embodiments, which also results in the inability to form a two-dimensional filler array. Therefore, its lubrication performance and stability performance are reduced compared to the embodiments.

[0088] In Comparative Example 7, since larger solid lubricating particles are used, it is difficult for them to be evenly distributed in the array of two-dimensional fillers during the surface distribution process. Therefore, the overall distribution characteristics are similar to the random distribution, which is very different from the embodiment. Therefore, the performance is close to Comparative Examples 5 and 6. In Comparative Example 8, since polyurethane resin is used as a bonding agent, its temperature stability is significantly lower than that of fluorocarbon resin, and its lubrication performance is also insufficient. In Comparative Example 9, since very few layers of MXene are used as fillers, its interlayer friction performance is significantly reduced, and the insufficient lubrication performance leads to a significant increase in the torque coefficient, and the overall torque coefficient stability is also significantly reduced.

[0089] In addition, the anti-corrosion performance and repeated tightening performance of the embodiments and comparative examples were also tested. The test results show that after 1500 hours of salt spray treatment, the embodiments can still maintain a good torque coefficient control effect, which is due to the good protective performance of the fluororesin and the strong barrier performance of the two-dimensional filler array. However, in comparative examples 1, 2 and 8, the long-term anti-corrosion performance is obviously insufficient due to the lack of fluororesin. In terms of repeated tightening, after one tightening, the undamaged bolts treated by the embodiments can be tightened a second time and maintain relatively close test results, while the comparative examples cannot maintain the stability of the torque coefficient again.

[0090] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A high-strength bolt surface treatment agent based on MXene directional arrangement, characterized in that The invention relates to a suspension dispersion composed of a two-dimensional MXene filler, a solid lubricating filler, a bonding agent, a solvent and an additive; wherein the two-dimensional MXene filler is a two-dimensional MXene filler whose surface is modified by a hyperbranched polyurethane; wherein the size of the solid lubricating filler is 1 μm to 3 μm; wherein the bonding agent is a mixture of a fluorocarbon resin and a latent curing agent; wherein the mass ratio of the two-dimensional MXene filler, the solid lubricating filler, the bonding agent, the solvent and the additive is 1: (3.5~5): (5.4~7.2): (10~15): (0.05~0.3).

2. According to the high-strength bolt surface treatment agent based on MXene directional arrangement according to claim 1, it is characterized in that The two-dimensional MXene filler is at least one of Ti3C2, Ta4C3, Mo2C, NbC, V2C, and Ti3CN prepared by chemical etching using the corresponding MAX phase, and the number of layers is 4 to 10; the hyperbranched polyurethane is a hyperbranched polyurethane molecule with a large number of terminal amine groups obtained by reacting diisocyanate and trifunctional polyol in dimethylformamide at a molar ratio of 2.1:1 and a concentration of 5%, and then adding diethylenetriamine for end-capping; wherein the diisocyanate is at least one of toluene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate, and the polyol is at least one of trivalent polyether polyol, trivalent polyester polyol, trivalent polycaprolactone polyol and trimethylolmethane; the branching degree of the hyperbranched polyurethane is 0.4 to 0.8, and the number average molecular weight is 6000-8000 Da.

3. According to the high-strength bolt surface treatment agent based on MXene directional arrangement according to claim 1, it is characterized in that The solid lubricating filler is at least one of CaF2, MoS2, graphite, boron nitride, and PTFE; the fluorocarbon resin in the adhesive fixative is at least one of water-based or solvent-based polyvinylidene fluoride resin, polytrifluorochloroethylene-vinyl ether resin, and polytetrafluorochloroethylene-vinyl ether resin; the latent curing agent is a low-temperature blocked isocyanate curing agent; and the mass ratio of the fluorocarbon resin to the latent curing agent is 1:(0.15~0.32).

4. According to claim 1, a high-strength bolt surface treatment agent based on MXene directional arrangement, characterized in that The solvent is at least one of water, methanol, ethanol, formic acid and benzyl alcohol; the auxiliary agent is at least one of a dispersant, a defoamer, a leveling agent and a thixotropic agent.

5. According to the high-strength bolt surface treatment agent based on MXene directional arrangement according to claim 1, characterized in that Prepared by the following steps: (1) Modification of two-dimensional MXene filler: soak the two-dimensional MXene filler in a modification solution containing a double-bond silane coupling agent at room temperature for 18 hours, and then place the silane-modified two-dimensional filler into the prepared hyperbranched polyurethane solution for reaction for 24 hours to obtain a hyperbranched polyurethane-modified two-dimensional MXene filler; wherein the modification solution is composed of 90% alcohol solvent, 9% ammonia water and 1% double-bond silane coupling agent, the alcohol solvent is at least one of methanol, ethanol, isopropanol and n-butanol, and the double-bond silane coupling agent is at least one of methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and vinyltrimethoxyethoxysilane; (2) Slurry dispersion: Weigh appropriate amounts of each component, use a high-speed disperser to disperse and mix the two-dimensional MXene filler with part of the adhesive and solvent at 3-5 m / s for 20 min, and then perform ultrasonic treatment for 6-8 min to obtain mixture A; stir the solid lubricating filler, additive and the remaining part of the adhesive and solvent at room temperature and disperse them in a ball mill for 4 h to obtain mixture B; add mixture A to mixture B at a linear speed of 6-10 m / s and disperse for 5-10 min until the system is uniform and stable to obtain a high-strength bolt surface treatment agent.

6. According to the treatment process of a high-strength bolt surface treatment agent based on MXene directional arrangement as described in claim 1, it is characterized in that The treatment process includes the following steps: (1) Cleaning: Use hot water at 60~70℃ to prepare a hot solution containing a surfactant cleaning agent, and adjust the pH value of the solution to 9~10. Place the bolt in the hot solution and use ultrasonic cleaning for 30 minutes. Rinse the surface solution with warm water and dry it at room temperature. (2) Spraying: Use a high-performance electrostatic spray machine to evenly spray the surface treatment agent onto the surface of the high-strength bolt. (3) Curing: Place the sprayed bolt in an oven to dry and cure for 2h~3h to obtain a surface-treated high-strength bolt with a stable torque coefficient.

7. According to the treatment process of a high-strength bolt surface treatment agent based on MXene directional arrangement as described in claim 1, it is characterized in that The spraying thickness of the surface treatment agent is 10 μm~20 μm, and the curing temperature of the surface treatment agent is 80℃~120℃.

8. Application of a high-strength bolt surface treatment agent based on MXene directional arrangement according to claim 1 for bolt connection secondary surface treatment in the fields of construction, industrial storage tanks, transportation infrastructure, small components, wind power main agent, etc.

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