Water-based adhesive solid lubricating coating based on nano lubricating material and preparation method thereof

Abstract

The invention relates to the technical field of water-based adhesive solid lubricating coatings, in particular to a water-based adhesive solid lubricating coating based on a nano lubricating material and a preparation method. The coating comprises the following components in parts by weight: 10 to 50 parts of a waterborne polyurethane resin binder, 20 to 120 parts of a waterborne polyamide-imide resin binder, 40 to 400 parts of deionized water, 10 to 60 parts of a solid lubricant, 1 to 10 parts of a coating reinforcing agent, 1 to 5 parts of a silicate solution, 0.1 to 4.5 parts of a wetting dispersant, 0.1 to 5 parts of a defoaming agent and 0.05 to 2 parts of a leveling aid. The halloysite and the spherical nano onion carbon material with the carbon shell structure are introduced into the coating, so that the lubricating property of the coating is effectively improved. By selecting a proper surfactant, the dispersity of the nano lubricating material in the water-based adhesive coating is enhanced, so that the green and environment-friendly water-based adhesive solid lubricating coating with excellent tribological performance is prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water-based adhesive solid lubricating coating, in particular to a water-based adhesive solid lubricating coating based on nano-lubricating material and a preparation method thereof. BACKGROUND

[0002] Friction and wear are ubiquitous in industrial production and daily life, and are important causes of energy consumption and economic loss. With the development of science and technology, adhesive solid lubricating coating as a commonly used lubricating protective material has become an effective means to solve the above problems. Adhesive solid lubricating coating effectively reduces friction and wear by mixing different functional components of materials and coating on the surface of parts, and ensures the stable operation of parts under high temperature, high load and severe environment. At present, typical adhesive solid lubricating coatings are mainly divided into two categories: organic solvent type and water-based. The organic solvent type adhesive solid lubricating coating is outstanding due to its excellent adaptability and mechanical properties. Compared with other solid lubricating coatings, it has a longer service life and lower maintenance cost. The above advantages make it widely used in aerospace, automobile industry, electronic equipment, medical devices and other fields.

[0003] However, the organic solvent type adhesive solid lubricating coating also has some deficiencies in practical application. For example, the solvents used by it have high volatility, which not only pollutes the environment, but also is difficult to meet the national environmental emission standards; at present, the commonly used coating preparation methods include spraying, electroplating, roll coating and dipping, etc. The flammable characteristics of volatile organic compounds (VOCs) in these processes may cause fire hazards and other safety hazards; in addition, the solvents and binders used by some coatings have special requirements for storage conditions and waste disposal, which further increases the complexity and cost of material application. Water-based adhesive solid lubricating coating uses water as the dispersion medium, and builds a more safe and environmentally friendly adhesive system. It has the advantages of high safety, energy saving and less environmental pollution in use. Therefore, the research and development of green water-based adhesive solid lubricating coating has become an important direction to promote the sustainable development of the industry.

[0004] At present, water-based adhesive solid lubricating coating still faces some technical problems in practical application which need to be broken through. For example, compared with organic solvent type resin, the adhesive strength and wear resistance of water-based resin still have certain gap; the compatibility of each component in the coating system is difficult to coordinate; in addition, the dispersion stability and wettability of nano-lubricating additives and functional fillers in water-based system are still insufficient. These problems limit the further improvement and wide application of water-based adhesive solid lubricating coating. SUMMARY

[0005] In view of the limitations of existing technologies, this invention provides an aqueous binder-based solid lubricating coating and its preparation method based on nano-lubricating materials. Halloysite and spherical nano-onion carbon materials with a carbon shell structure are introduced into the coating, effectively improving the lubrication performance of the coating. By selecting a suitable surfactant, the dispersibility of the nano-lubricating materials in the aqueous binder-based coating is enhanced, thereby preparing an environmentally friendly aqueous binder-based solid lubricating coating with excellent tribological properties.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A water-based binder solid lubricant coating based on nano-lubricating materials comprises the following components in parts by weight: 10-50 parts of water-based polyurethane resin binder, 20-120 parts of water-based polyamide-imide resin binder, 40-400 parts of deionized water, 10-60 parts of solid lubricant, 1-10 parts of coating strengthener, 1-5 parts of silicate solution, 0.1-4.5 parts of wetting and dispersing agent, 0.1-5 parts of defoamer, and 0.05-2 parts of leveling aid.

[0007] Preferably, the components include the following parts by weight: 30 parts of waterborne polyurethane resin binder, 90 parts of waterborne polyamide-imide resin binder, 330 parts of deionized water, 20 parts of solid lubricant, 2 parts of coating strengthening agent, 3 parts of silicate solution, 2.5 parts of wetting and dispersing agent, 3 parts of defoamer, and 1 part of leveling aid; wherein the solid lubricant includes 15 parts of surface-modified nano-onion carbon and 5 parts of halloysite.

[0008] A method for preparing an aqueous binder-type solid lubricating coating based on nano-lubricating materials includes the following steps: (1) First, onion carbon was oxidized with mixed acid to introduce polar functional groups and then dried to obtain nano-onion carbon material preform; then, polyvinylpyrrolidone (PVP), γ-aminopropyltriethoxysilane (APTES) and dibutyltin dilaurate (DBTDL) catalyst were introduced into ethanol solution, and the nano-onion carbon material preform was placed in it and refluxed at 80°C for 8 h. Hydrophilic modification was achieved by silane covalent grafting and PVP coating; after washing and drying, hydrophilic spherical surface-modified nano-onion carbon material was obtained. (2) Preparation of predispersant A: First, the wetting and dispersing agent is mixed with a small amount of deionized water and mechanically stirred for 1 h. Then, the mixed solution is poured into a ball mill jar. Subsequently, the solid lubricant, coating strengthening agent and grinding beads are added to the ball mill jar and ball milled for 3 h to obtain predispersant A for later use. (3) Preparation of predispersant B: Silicate solution, leveling agent, waterborne polyurethane resin binder and waterborne polyamide-imide resin binder and an appropriate amount of deionized water are mixed and mechanically stirred for 0.5 h at 40-60 ℃, and then dispersed with an ultrasonic probe for 0.2 h to prepare predispersant B; (4) Preparation of water-based adhesive solid lubricating coating: Predispersant A and predispersant B are mixed and defoamer is added. The mixture is dispersed at 800-1000 rpm for 1 h and filtered through a 200-mesh filter cloth to finally obtain water-based adhesive solid lubricating coating. (5) Coating preparation: The prepared water-based adhesive solid lubricant coating is uniformly sprayed onto the surface of the pretreated substrate and cured under appropriate temperature conditions to form the desired water-based adhesive solid lubricant coating.

[0009] Preferably, in step (1), the acid in the mixed acid oxidation is a mixture of nitric acid (HNO3), sulfuric acid (H2SO4) and deionized water; the mass ratio of onion carbon, nitric acid (HNO3), sulfuric acid (H2SO4) and deionized water is 1:0.25:0.25:2.5.

[0010] Preferably, in step (1), the mass ratio of the nano-onion carbon material preform, ethanol solution, polyvinylpyrrolidone (PVP), γ-aminopropyltriethoxysilane (APTES), and dibutyltin dilaurate (DBTDL) catalyst is 1:3:0.03:0.04:0.0004.

[0011] Preferably, in step (2), the wetting and dispersing agent is one of polyacrylate and fatty alcohol polyoxyethylene ether, the solid lubricant is the spherical surface-modified nano-onion carbon material with a particle size of 30-60 nm and halloysite with a particle size of 2-8 μm obtained in step (1), and the coating reinforcing agent is one of kaolin and talc with a particle size between 1-5 μm; wherein, the mass ratio of the wetting and dispersing agent to deionized water is 1:200.

[0012] Preferably, in step (3), the silicate solution is at least one of silica sol, nano alumina sol, and sodium silicate solution; the leveling agent is one of polyether modified polydimethylsiloxane and dodecyl alcohol ester; the solid content of the waterborne polyurethane resin adhesive is 40%-70%, and the solid content of the waterborne polyamide-imide resin adhesive is 30%-36%; wherein, the mass ratio of silicate solution, leveling agent, waterborne polyurethane resin adhesive (PU), waterborne polyamide-imide resin adhesive (PAI), and deionized water is 3:1:30:90:100.

[0013] Preferably, in step (4), the defoamer is one of silicone defoamer, fatty acid ester defoamer, and polyether defoamer; the filter cloth has a sieve particle size of 200#.

[0014] Preferably, in step (5), the surface of the substrate is subjected to sandblasting to remove dirt, ultrasonic cleaning and drying treatment; the curing conditions are: surface drying at room temperature for 3 hours, then heat drying in an oven at 80-130 ℃ for 2 hours, and finally heat curing at 180-210 ℃; the coating thickness ranges from 10 to 80 μm.

[0015] The beneficial effects of this invention, a water-based binder solid lubricating coating based on nano-lubricating materials and its preparation method, are as follows: 1. This invention selects waterborne polyurethane resin (PU) and waterborne polyamide-imide (PAI) as binders. These materials not only have a wide temperature range and excellent corrosion resistance, but can also be dispersed with water in any proportion, significantly improving environmental friendliness and operational safety.

[0016] 2. The coating preparation process is simple. Only appropriate surface modification of the solid lubricant is required, and good dispersion can be achieved by combining physical dispersion methods such as grinding and ultrasound. There is no need to introduce complex chemical reaction processes, thereby improving the controllability and repeatability of the preparation process.

[0017] 3. Halloysite, as a lubricating additive, is a naturally occurring, inexpensive, and non-toxic nanoparticle. Onion-shaped carbon nanomaterials, with their excellent self-lubricating properties, endow the coating with outstanding tribological properties.

[0018] 4. This coating is widely applicable to special scenarios and extreme working conditions such as space environments and weaponry, significantly extending the service life of equipment, thereby reducing costs and minimizing resource waste.

[0019] 5. Compared with other lubrication methods, this coating has a significant advantage in terms of economy, effectively reducing maintenance and production costs. With its green and environmentally friendly characteristics and superior performance, water-based bonded solid lubricating coatings show broad application prospects. Attached Figure Description

[0020] Figure 1 The graph shows the coefficient of friction of the bonded solid lubricating coating provided in Example 1 as a function of time. Figure 2 The graph shows the coefficient of friction of the bonded solid lubricating coating provided in Example 2 as a function of time. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0022] This invention provides the following technical solution: A water-based binder solid lubricant coating based on nano-lubricating materials comprises the following components in parts by weight: 10-50 parts of water-based polyurethane resin binder, 20-120 parts of water-based polyamide-imide resin binder, 40-400 parts of deionized water, 10-60 parts of solid lubricant, 1-10 parts of coating strengthener, 1-5 parts of silicate solution, 0.1-4.5 parts of wetting and dispersing agent, 0.1-5 parts of defoamer, and 0.05-2 parts of leveling aid.

[0023] The optimal formulation comprises the following components in parts by weight: 30 parts of waterborne polyurethane resin binder, 90 parts of waterborne polyamide-imide resin binder, 330 parts of deionized water, 20 parts of solid lubricant, 2 parts of coating strengthening agent, 3 parts of silicate solution, 2.5 parts of wetting and dispersing agent, 3 parts of defoamer, and 1 part of leveling aid; wherein the solid lubricant comprises 15 parts of surface-modified nano-onion carbon and 5 parts of halloysite.

[0024] This invention also discloses a method for preparing an aqueous binder solid lubricating coating based on nano-lubricating materials, comprising the following steps: (1) First, onion carbon was oxidized with mixed acid to introduce polar functional groups and then dried to obtain nano-onion carbon material preform; then, polyvinylpyrrolidone (PVP), γ-aminopropyltriethoxysilane (APTES) and dibutyltin dilaurate (DBTDL) catalyst were introduced into ethanol solution, and the nano-onion carbon material preform was placed in it and refluxed at 80°C for 8 h. Hydrophilic modification was achieved by silane covalent grafting and PVP coating; after washing and drying, hydrophilic spherical surface-modified nano-onion carbon material with uniform surface modification and excellent dispersion stability was obtained. (2) Preparation of predispersant A: First, the wetting and dispersing agent is mixed with a small amount of deionized water and mechanically stirred for 1 h. Then, the mixed solution is poured into a ball mill jar. Subsequently, the solid lubricant, coating strengthening agent and grinding beads are added to the ball mill jar and ball milled for 3 h to obtain a uniform predispersant A for later use. (3) Preparation of predispersant B: Silicate solution, leveling agent, waterborne polyurethane resin adhesive (PU) and waterborne polyamide-imide resin adhesive (PAI) and an appropriate amount of deionized water are mixed and mechanically stirred for 0.5 h at 40-60 ℃, and then dispersed with an ultrasonic probe for 0.2 h to prepare predispersant B; (4) Preparation of water-based adhesive solid lubricating coating: Pre-dispersion liquid A and pre-dispersion liquid B are mixed and defoamer is added. The mixture is dispersed at a speed of 800-1000 rpm for 1 h and filtered through a 200-mesh filter cloth to finally obtain a uniform water-based adhesive solid lubricating coating. (5) Coating preparation: The prepared water-based adhesive solid lubricant coating is uniformly sprayed onto the surface of the pretreated substrate and cured under appropriate temperature conditions to form the desired water-based adhesive solid lubricant coating.

[0025] Specifically, in step (1), the acid in the mixed acid oxidation is a mixture of nitric acid (HNO3), sulfuric acid (H2SO4) and deionized water; the mass ratio of onion carbon, nitric acid (HNO3), sulfuric acid (H2SO4) and deionized water is 1:0.25:0.25:2.5.

[0026] Specifically, in step (1), the mass ratio of the nano-onion carbon material preform, ethanol solution, polyvinylpyrrolidone (PVP), γ-aminopropyltriethoxysilane (APTES), and dibutyltin dilaurate (DBTDL) catalyst is 1:3:0.03:0.04:0.0004.

[0027] Specifically, in step (2), the wetting and dispersing agent is one of polyacrylate or fatty alcohol polyoxyethylene ether, the solid lubricant is the spherical surface-modified nano-onion carbon material with a particle size of 30-60 nm and halloysite with a particle size of 2-8 μm obtained in step (1), and the coating reinforcing agent is one of kaolin or talc with a particle size between 1-5 μm; wherein, the mass ratio of the wetting and dispersing agent to deionized water is 1:200.

[0028] Specifically, in step (3), the silicate solution is at least one of silica sol, nano alumina sol, and sodium silicate solution; the leveling agent is one of polyether modified polydimethylsiloxane and dodecyl alcohol ester; the solid content of the waterborne polyurethane resin adhesive is 40%-70%, and the solid content of the waterborne polyamide-imide resin adhesive is 30%-36%; wherein, the mass ratio of silicate solution, leveling agent, waterborne polyurethane resin adhesive (PU), waterborne polyamide-imide resin adhesive (PAI), and deionized water is 3:1:30:90:100.

[0029] Specifically, in step (4), the defoamer is one of the following: silicone defoamer, fatty acid ester defoamer, and polyether defoamer; the filter cloth has a sieve particle size of 200#.

[0030] Specifically, in step (5), the surface of the substrate is subjected to sandblasting to remove dirt, ultrasonic cleaning and drying treatment; the curing conditions are: surface drying at room temperature for 3 hours, then heat drying in an oven at 80-130 ℃ for 2 hours, and finally heating and curing at 180-210 ℃; the coating thickness ranges from 10 to 80 μm.

[0031] The specific embodiments of the present invention will be described below with reference to the above technical solutions: Example 1: Weigh out 30 g of waterborne polyurethane resin, 90 g of waterborne polyamide-imide, 35 g of surface-modified nano-onion carbon, 15 g of halloysite, 2.5 g of wetting agent, 3 g of silica sol, 2 g of functional filler (i.e., coating strengthener), 1 g of leveling agent, 3 g of defoamer, and 330 g of deionized water. First, mix the wetting agent, nano-onion carbon, halloysite, functional filler, and a small amount of deionized water, mechanically stir for 40 min, and disperse using a ball mill for 2 h to obtain a pre-dispersion. Then, mix the waterborne polyurethane resin, waterborne polyamide-imide, silica sol, leveling agent, and the remaining deionized water, mechanically stir for 0.5 h, and ultrasonically disperse for 10 min to obtain a resin matrix system. Slowly add the pre-dispersion to the matrix system, stir at high speed until homogeneous, and then add the defoamer to obtain a uniform waterborne composite coating. Apply the coating evenly to a cleaned metal substrate by spraying, dry at room temperature, and then heat-cur in an oven to obtain a composite adhesive solid lubricating coating. The obtained coating was subjected to a sliding friction and wear test with a load of 5 N, a sliding frequency of 4 Hz, an amplitude of 4 mm, and a test duration of 1800 s. The results are as follows: Figure 1 As shown, the coefficient of friction of the coating is stable at about 0.18, exhibiting excellent self-lubricating properties.

[0032] Example 2: The material weighing and mixing ratios are the same as in Example 1, and the coating preparation process is identical. The difference lies in: The treated metal substrate was fixed on a spin coater, and the prepared water-based coating was dropped onto the center of the substrate. The coating was then spin-coated at 2000 rpm for 30 seconds to form a uniform coating. After standing at room temperature for 10 minutes, it was pre-cured at 80 °C, and finally heat-cured in a 210 °C oven for 2 hours to obtain a composite solid lubricating coating. Figure 2 As shown, under the same friction test conditions, the coating prepared by spin coating method has a uniform thickness and a friction coefficient that is slightly lower than that of the sprayed sample, remaining stable between 0.1 and 0.15, exhibiting better surface uniformity and wear resistance.

[0033] This invention employs a water-based coating with water as the dispersion medium, replacing traditional organic solvent systems, significantly reducing volatile organic compound (VOC) emissions and improving environmental friendliness and operational safety. By surface-modifying the solid lubricant, its dispersibility and stability in the water-based system are effectively improved, avoiding agglomeration and ensuring coating uniformity and reliability. The preparation process of this invention is based on a water-based system, with a simple flow involving only mixing, coating, and curing steps, resulting in low cost and suitability for large-scale production. More importantly, the prepared green composite bonded solid lubricant coating not only possesses excellent friction-reducing and wear-resistant properties but also withstands high temperatures (300°C) and high vacuum (100°C) without damage. -3 Even under extreme environments such as Pa, it can still maintain good lubrication and protection effects, effectively extending the service life of the substrate.

Claims

1. Waterborne adhesive solid lubricating coating based on nanolubricating materials, characterized by: The water-based adhesive solid lubricating coating composition comprises the following components in parts by weight: water-based polyurethane resin binder 10-50 parts, water-based polyamide-imide resin binder 20-120 parts, deionized water 40-400 parts, solid lubricant 10-60 parts, coating strengthening agent 1-10 parts, silicate solution 1-5 parts, wetting dispersant 0.1-4.5 parts, defoaming agent 0.1-5 parts, and leveling aid 0.05-2 parts.

2. The aqueous, binder solid lubricating coating based on nanolubricating materials according to claim 1, characterized by: The water-based adhesive solid lubricating coating composition comprises the following components in parts by weight: water-based polyurethane resin binder 30 parts, water-based polyamide-imide resin binder 90 parts, deionized water 330 parts, solid lubricant 20 parts, coating strengthening agent 2 parts, silicate solution 3 parts, wetting dispersant 2.5 parts, defoaming agent 3 parts, and leveling aid 1 part; wherein the solid lubricant comprises surface-modified nano-onion carbon 15 parts and halloysite 5 parts.

3. The coating preparation method of the water-based cohesive solid lubricating coating based on nanolubricating materials according to claim 1, characterized by: The method comprises the following steps: (1) first, the onion carbon is oxidized by mixed acid to introduce polar functional groups, and then dried to obtain a nano-onion carbon material preform; then, polyvinylpyrrolidone, γ-aminopropyl triethoxysilane and dibutyltin dilaurate catalyst are introduced into the nano-onion carbon material preform in an ethanol solution, and refluxed at 80℃ for 8 hours to realize hydrophilic modification through silane covalent grafting and PVP coating; after washing and drying, a hydrophilic spherical surface-modified nano-onion carbon material is obtained; (2) preparation of pre-dispersion A: first, the wetting dispersant is mixed with a small amount of deionized water, and mechanically stirred for 1 hour; then, the mixed solution is poured into a ball mill tank; then, the solid lubricant, the coating strengthening agent and the grinding beads are added into the ball mill tank, and ball milling is carried out for 3 hours to obtain the pre-dispersion A, which is ready for use; (3) preparation of pre-dispersion B: the silicate solution, the leveling aid, the water-based polyurethane resin binder, the water-based polyamide-imide resin binder and the appropriate amount of deionized water are mixed, and mechanically stirred at 40-60℃ for 0.5 hours; then, the pre-dispersion B is prepared by ultrasonic probe dispersion for 0.2 hours; (4) preparation of the water-based adhesive solid lubricating coating: the pre-dispersion A and the pre-dispersion B are mixed, and the defoaming agent is added, and dispersed at a speed of 800-1000 rpm for 1 hour, and filtered through a 200-mesh filter cloth, to obtain the water-based adhesive solid lubricating coating; (5) coating preparation: the prepared water-based adhesive solid lubricating coating is uniformly sprayed on the surface of the substrate after surface pretreatment, and is cured under appropriate temperature conditions to form the required water-based adhesive solid lubricating coating.

4. The coating preparation method of the water-based cohesive solid lubricating coating based on nanolubricating materials according to claim 3, characterized by: In the step (1), the acid in the mixed acid oxidation is a mixture of nitric acid, sulfuric acid and deionized water; the mass ratio of onion carbon, nitric acid, sulfuric acid and deionized water is 1:0.25:0.25:2.

5.

5. The coating preparation method of the water-based cohesive solid lubricating coating based on nanolubricating materials according to claim 3, characterized by: In the step (1), the mass ratio of the nano-onion carbon material preform, the ethanol solution, the polyvinylpyrrolidone, the γ-aminopropyl triethoxysilane and the dibutyltin dilaurate catalyst is 1:3:0.03:0.04:0.0004.

6. The coating preparation method of water-based adhesive solid lubricating coating based on nanolubricating material according to claim 3, characterized by: The wetting dispersant is one of polyacrylate, fatty alcohol polyoxyethylene ether, the solid lubricant is the spherical surface modified nano onion carbon material with particle size of 30-60 nm and halloysite with particle size of 2-8 μm obtained in step (1), the coating strengthening agent is one of kaolin and talcum powder with particle size of 1-5 μm; wherein, the mass ratio of the wetting dispersant to deionized water is 1:

200.

7. The coating preparation method of water-based adhesive solid lubricating coating based on nanolubricating material according to claim 3, characterized by: In the step (3), the silicate solution is at least one of silica sol, nano alumina sol and sodium silicate solution; the leveling aid is one of polyether modified polydimethylsiloxane and lauryl alcohol ester; the solid content of the water-based polyurethane resin binder is 40%-70%, and the solid content of the water-based polyamide-imide resin binder is 30%-36%; wherein, the mass ratio of the silicate solution, the leveling aid, the water-based polyurethane resin binder, the water-based polyamide-imide resin binder and deionized water is 3:1:30:90:

100.

8. The coating preparation method of the water-based cohesive solid lubricating coating based on nanolubricating materials according to claim 3, characterized by: In the step (4), the defoaming agent is one of silicone defoaming agent, fatty acid ester defoaming agent and polyether defoaming agent; the filter cloth screen particle size is 200#.

9. The coating preparation method of the water-based cohesive solid lubricating coating based on nanolubricating materials according to claim 3, characterized by: In the step (5), the substrate surface is treated by sand blasting, ultrasonic cleaning and drying; the curing conditions are: 3 h of surface drying at room temperature, then placed in an oven for heat preservation and drying at 80-130 ℃ for 2 h, and finally heated and cured at 180-210 ℃; the coating thickness is in the range of 10-80 μm.

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