A kind of coating for columnar metal part processing feeding device and its preparation method

Abstract

This invention discloses a coating for a feeding device used in the processing of columnar metal parts and its preparation method, belonging to the field of coating technology. It comprises modified diatomaceous earth, phytosterols, aluminum naphthenate, modified alkyl glycosides, hydrogenated rosin, polyadipate-hydroxyapatite complex, potassium borate, and modified polyglycerol fatty acid ester-calcium stearate complex, etc. The modified diatomaceous earth is modified with a silane coupling agent and aluminum tripolyphosphate and then calcined and cured. The modified alkyl glycosides are obtained by modification with potassium borate. The modified polyglycerol fatty acid ester-calcium stearate complex is modified by cage-type silsesquioxane coating. In preparation, hydrogenated rosin and the polyadipate-hydroxyapatite complex are dispersed by heating, and the modified diatomaceous earth and other components are added sequentially. After cooling, the remaining components are added, followed by grinding, filtration, and degassing to obtain the final product. This coating is suitable for high-cleanliness, lubrication-free dry conveying conditions and possesses excellent properties such as wear resistance, stability, low dust, low precipitation, and antistatic properties.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically a coating for a feeding device used in the processing of columnar metal parts and its preparation method. Background Technology

[0002] In the fields of vacuum equipment and precision instrument manufacturing, precision columnar metal parts to be processed (which will later be used to manufacture vacuum chamber columns, vacuum flange columns, vacuum sealing columns, precision guide columns, positioning columns, etc.) are core basic components that ensure the sealing reliability, motion guidance accuracy, and structural connection stability of vacuum systems. Before entering precision machining equipment such as CNC lathes, machining centers, and precision grinding machines, these precision columnar parts need to rely on a special feeding device to complete orientation and alignment, stable support, smooth conveying, and process transition connection, so as to achieve orderly and controllable feeding of workpieces from storage bins to precision machining stations.

[0003] Among them, the feeding trough (V-shaped material channel), guide plate, and transition slide are the core contact components of the feeding device. Their performance directly determines the workpiece conveying quality and surface protection effect. The three have a clear division of functions: the feeding trough (V-shaped material channel) serves as the main load-bearing and guiding component, providing directional support and double-sided limiting for columnar parts, ensuring that the workpiece slides in a straight line along the preset path, and providing stable material supply for the precision machining station; the guide plate is used to support medium and long columnar precision parts, ensuring that the workpiece slides smoothly and avoids collisions; the transition slide is arranged at each process or conveying connection point to realize the smooth transition of the workpiece across sections and eliminate conveying drop and turning impact.

[0004] Throughout the entire feeding and conveying process, the aforementioned columnar precision metal parts are in close contact with the surfaces of the feeding trough, guide plate, and transition slide, accompanied by repeated sliding and rolling friction. However, these core contact components for feeding often involve direct contact between the metal substrate and the workpiece, or are merely coated with simple protective materials such as ordinary adhesive rubber or conventional polyurethane coatings. Since the workpieces are subsequently used in vacuum equipment, the conveying process must meet high cleanliness and lubrication-free dry conditions. Conventional protective materials are unsuitable for this working condition, presenting the following technical problems: Firstly, to meet vacuum sealing requirements, grease lubrication is strictly prohibited throughout the entire transport process, and the workpiece is in a dry friction environment. Ordinary coatings are prone to wear, powdering, and peeling under long-term repeated dry sliding friction, generating debris and dust. Among them, micron-sized metal shavings are prone to adhesion and accumulation, which not only scratches the precision mirror surface of the workpiece with Ra≤0.4 grade, but also contaminates the vacuum sealing surface and reduces the sealing performance of the vacuum system. At the same time, under unlubricated dry friction conditions, existing conventional coatings are either too hard and have insufficient surface smoothness, or too soft and have poor wear resistance. When transporting ultra-precision cylindrical parts, they are very prone to fine scratches and indentations, which directly affect the surface finishing quality of the workpiece.

[0005] Secondly, the precision columnar components inside vacuum equipment need to operate under ultra-high vacuum conditions, which places stringent requirements on their surfaces for ultra-high cleanliness, low residue, and low outgassing. Conventional organic protective coatings on the surface of the feeding mechanism are prone to leaving volatile components and moisture. Coating debris and dust generated during the conveying process will adhere to the surface of the workpiece. Organic precipitates from the coating and dust will continue to be released and volatilized after entering the vacuum chamber with the workpiece, resulting in a decrease in the vacuum level and deterioration of the cleanliness of the chamber, which will affect the stable operation of the vacuum system.

[0006] Third, the transport of such workpieces needs to be carried out in a high-cleanliness workshop environment, and the dry sliding friction between the workpiece and the ordinary coating surface will continuously generate and accumulate static electricity; conventional coatings lack antistatic ability, on the one hand, they will firmly adsorb impurities such as metal shavings and trace amounts of oil, and on the other hand, they will adsorb nano-sized dust below 0.1μm and submicron dust of 0.1–1μm in the workshop. After these impurities adhere to the sealing surface of the workpiece, conventional wiping processes are difficult to remove them effectively, reducing the product qualification rate.

[0007] Based on this, we developed a special protective coating suitable for feeding troughs, guide plates, and transition slides to solve the above-mentioned technical problems. This coating has significant engineering application value and practical necessity. Summary of the Invention

[0008] The purpose of this invention is to provide a coating and its preparation method for a feeding device for processing columnar metal parts. This invention aims to solve the technical problems of existing coatings having insufficient wear resistance and stability under dry conditions without lubrication, easy dust precipitation that contaminates the vacuum cavity, and easy electrostatic adsorption of dust, thereby meeting the high-cleanliness requirements for conveying precision columnar metal parts.

[0009] The objective of this invention is achieved through the following technical solution: A coating for a feeding device used in machining columnar metal parts comprises the following components in parts by weight: 30-40 parts modified diatomaceous earth, 8-12 parts phytosterols, 5-8 parts aluminum naphthenate, 3-5 parts modified alkyl glycosides, 10-15 parts hydrogenated rosin, 20-25 parts polyadipate-hydroxyapatite complex, 3-5 parts potassium borate, 2-4 parts modified polyglycerol fatty acid ester-calcium stearate complex, and 18-22 parts deionized water; The modified diatomaceous earth is obtained by first modifying diatomaceous earth with a silane coupling agent, then modifying it with aluminum tripolyphosphate complexation passivation, and finally calcining and ripening it. The modified alkyl glycoside is obtained by modifying alkyl glycoside with potassium borate; The modified polyglycerol fatty acid ester-calcium stearate composite is obtained by melt blending polyglycerol fatty acid ester-calcium stearate and then modifying it by coating the surface with cage-type silsesquioxane.

[0010] The coating provided by this invention is suitable for high-cleanliness, lubrication-free dry conveying conditions. It can improve the problems of insufficient wear resistance and stability of existing coatings, easy generation of micro-dust pollution, uneven surface resistance, easy adhesion during long-term friction, and easy release of precipitates into the vacuum cavity. The function or mechanism of the components is as follows: After emulsification, hydrogenated rosin serves as the main film-forming matrix for coatings, forming a continuous phase skeleton for the coating. It provides basic film-forming ability, workability, and substrate adhesion, and provides a uniformly dispersed carrier for each functional component, ensuring the overall structural stability of the coating.

[0011] Diatomaceous earth, as a rigid functional filler, possesses porous adsorption properties, which can adsorb micro-dust generated by dry friction and reduce the free diffusion of micro-dust. Diatomaceous earth is modified with silane coupling agents to improve its compatibility with organic components and reduce particle agglomeration. Then, it is passivated by aluminum tripolyphosphate complexation, where phosphate groups coordinate with silanol groups to block the surface pores and reduce adsorption capacity. Finally, it is calcined and cured at low temperature to promote secondary cross-linking of the surface film, close residual micropores, reduce micro-dust shedding, and reduce the risk of gas release pollution.

[0012] Alkyl glycosides, as dispersants and surfactants, possess surface activity and dispersing properties, which can improve the uniformity of dispersion of various components in coatings. After modification with potassium borate, the borate ions dissociated from potassium borate coordinate with the hydroxyl groups of alkyl glycosides to form stable ionic complexes. This creates continuous ionic conductive channels within the coating, balancing the surface resistivity of the coating, alleviating electrostatic accumulation in the coating, and reducing the risk of dust adsorption in the coating.

[0013] Phytosterols, as lubricating components, can improve coating lubricity and reduce coating friction resistance; aluminum naphthenate, as a stabilizing and densifying agent, can enhance coating density and stability; the combined use of phytosterols and aluminum naphthenate can form a low-friction interface and reduce workpiece sliding resistance.

[0014] The polyadipate-hydroxyapatite composite serves as a flexible-rigid composite reinforcing framework. Polyadipate provides flexibility to the composite, while hydroxyapatite provides rigid support. The combination of polyadipate and hydroxyapatite can improve the heat resistance stability of the coating, alleviate the softening of the substrate caused by long-term dry friction heat accumulation (generally ≤60℃), and reduce the risk of coating debris adhesion.

[0015] In the modified polyglycerol fatty acid ester-calcium stearate composite, polyglycerol fatty acid ester serves as a compatibility and emulsification aid, while calcium stearate acts as a lubricant and stabilizer. After melt blending, the composite is further modified by surface coating with cage-type silsesquioxane, which forms a barrier layer on the surface. This reduces the release of low molecular weight components from the composite and their adhesion to the workpiece surface, preventing them from being released and volatilized after entering the vacuum chamber with the workpiece. The composite also improves the compatibility between phytosterols and aluminum naphthenate, preventing the formation of micro-protrusions on the coating surface.

[0016] In summary, the coating provided by this invention uses hydrogenated rosin as the continuous phase skeleton and diatomaceous earth and polyadipate-hydroxyapatite composite as the reinforcing skeleton. Through the synergistic effect of each functional component, it can be adapted to high-cleanliness, lubrication-free dry conveying conditions, improve the coating's wear resistance and stability, reduce dust release, reduce precipitation, and enhance antistatic uniformity. It also reduces the risk of surface scratches and contamination during the conveying of precision columnar parts, prevents contaminants on the workpiece surface from being introduced into the vacuum cavity and affecting the stability of the vacuum system, and ensures long-term stability.

[0017] Preferably, in the modified diatomaceous earth, the mass ratio of diatomaceous earth, silane coupling agent, and aluminum tripolyphosphate is 100:(1.5-3):(15-25).

[0018] Preferably, the roasting and cooking temperature is 120-140℃ and the time is 40-60 min.

[0019] Preferably, in the polyadipate-hydroxyapatite composite, the mass ratio of polyadipate to hydroxyapatite is (4-6):1.

[0020] Preferably, in the modified polyglycerol fatty acid ester-calcium stearate composite, the mass ratio of polyglycerol fatty acid ester, calcium stearate, and cage-like silsesquioxane is (3-5):1:(0.1-0.3).

[0021] Preferably, the potassium borate has a particle size of 600-800 mesh, and the diatomaceous earth has a particle size of 800-1200 mesh.

[0022] Preferably, in the modified alkyl glycoside, the amount of potassium borate is 3% to 6% of the mass of the alkyl glycoside.

[0023] In addition, to achieve the above objectives, the present invention also provides a method for preparing a coating for a feeding device used in the processing of columnar metal parts. Hydrogenated rosin and a polyadipate-hydroxyapatite composite are added to a dispersion vessel, heated to 40-60°C, and stirred and dispersed. Modified diatomaceous earth, phytosterols, aluminum naphthenate, and deionized water are added sequentially. The temperature is raised to 55-75°C, dispersed, and then cooled to 40-50°C. Modified alkyl glycosides, potassium borate, and a modified polyglycerol fatty acid ester-calcium stearate composite are added. After stirring and dispersing, the coating is ground, filtered, and degassed under vacuum to obtain the finished product.

[0024] Preferably, the hydrogenated rosin needs to undergo emulsification treatment before use, specifically: first, the hydrogenated rosin is melted, and then 8% to 12% of its mass of fatty alcohol polyoxyethylene ether is added for emulsification.

[0025] Compared with the prior art, the beneficial effects of the present invention are: This invention uses hydrogenated rosin as the continuous film-forming phase framework and constructs a rigid-flexible composite reinforcement system with modified diatomaceous earth and polyadipate-hydroxyapatite composites. Simultaneously, it incorporates functional components such as modified alkyl glycosides, phytosterols, aluminum naphthenate, and modified polyglycerol fatty acid ester-calcium stearate composites. These components synergistically enhance the overall performance of the coating. Experiments show that the wear rate of the coating of this invention is ≤3.5 mg / 10. 4 Secondly, it exhibits excellent dry-state wear resistance and low dust release; the total exudation rate is ≤0.92%, with a low level of small molecule exudation, effectively reducing the risk of gas release contamination in the vacuum chamber; the surface resistivity is ≤3.1×10⁻⁶. 8 Ω The coating exhibits a clean, antistatic properties suitable for clean environments, with a dust adsorption capacity ≤0.24 mg / cm², demonstrating a balanced antistatic and dust-suppressing capacity. Its peel strength is ≤3.1 N / cm, exhibiting good dry-state anti-adhesion performance. Adhesion strength is ≥4.0 MPa, ensuring a strong bond between the coating and the substrate and strong structural stability. This coating is suitable for high-cleanliness, lubrication-free, dry-state conveying conditions of columnar metal parts, effectively reducing the risk of surface scratches and contamination, preventing contaminants from being introduced into the vacuum chamber and affecting system stability, ensuring long-term stability, and meeting the requirements of precision columnar metal parts processing and feeding devices. Detailed Implementation

[0026] Example 1 1. Preparation of non-commercially available components (components whose preparation methods are not mentioned are all commercially available components): (1) Modified diatomaceous earth: The materials were prepared according to the mass ratio of diatomaceous earth (particle size of 800 mesh), silane coupling agent and aluminum tripolyphosphate of 100:2:20. Specifically, the diatomaceous earth was first added to deionized water to prepare a suspension with a mass fraction of 15%, and then ultrasonically dispersed at a power of 300 W and a frequency of 20 kHz for 30 min; then silane coupling agent KH550 was added, the temperature was raised to 70℃, and the mixture was stirred at a constant temperature of 600 r / min for 2 h; then aluminum tripolyphosphate was added, and the mixture was stirred at 600 r / min for 1 h; then the mixture was filtered, the filter cake was washed twice with deionized water, calcined and matured at 130℃ for 50 min, cooled, ground and passed through a 1000 mesh sieve to obtain modified diatomaceous earth.

[0027] (2) Modified alkyl glycosides: Alkyl glycosides (a mixture of C12, C13 and C14 alkyl glycosides in a mass ratio of 6:3:1) were prepared into an aqueous solution with a mass fraction of 50% and dissolved by stirring at 400 r / min at 50℃; then 4.5% of potassium borate (700 mesh particle size) by mass of alkyl glycosides were added, the temperature was raised to 65℃, and the reaction was stirred at 500 r / min for 1.5 h; then the mixture was concentrated under reduced pressure to a solid content of 50%, and after cooling, the modified alkyl glycosides were obtained.

[0028] (3) Polyadipate-hydroxyapatite composite: Polyadipate (selected from polyhexamethylene adipate, molecular weight 2000 Da, hydroxyl value 32 mg KOH / g) and hydroxyapatite (particle size 800 mesh) were prepared at a mass ratio of 5:1. Specifically, the polyadipate was heated to 80°C to melt, and then hydroxyapatite was added. The mixture was stirred at 80°C at 800 r / min for 30 min. After cooling, it was ground and passed through a 1000 mesh sieve to obtain the composite.

[0029] (4) Modified polyglycerol fatty acid ester-calcium stearate composite: The materials were prepared in a mass ratio of polyglycerol fatty acid ester, calcium stearate, and cage-like silsesquioxane of 4:1:0.2. Specifically, the polyglycerol fatty acid ester and calcium stearate were heated to 120°C to melt and stirred at 600 r / min for 20 min; then cooled to 80°C, and cage-like silsesquioxane (selected from epoxy-based cage-like silsesquioxane, EP-POSS) and 5% by mass of cage-like silsesquioxane silane coupling agent KH560 were added and stirred at 800 r / min for 30 min; after cooling, the mixture was ground and passed through a 400-mesh sieve to obtain the modified composite.

[0030] 2. Coating preparation: Take 35 parts by weight of modified diatomaceous earth, 10 parts by weight of phytosterol (selected from β-sitosterol, purity ≥95%), 6.5 parts by weight of aluminum naphthenate (aluminum content 5%, acid value 75 mg KOH / g), 4 parts by weight of modified alkyl glycoside (based on solid active ingredient), 12.5 parts by weight of hydrogenated rosin (softening point 85℃, acid value 165 mg KOH / g, degree of hydrogenation ≥95%), 22.5 parts by weight of polyadipate-hydroxyapatite complex, 4 parts by weight of potassium borate, 3 parts by weight of modified polyglycerol fatty acid ester-calcium stearate complex, and 20 parts by weight of deionized water. Specifically: First, hydrogenated rosin is heated to 100℃ and melted. Then, 10% of its mass of fatty alcohol polyoxyethylene ether (AEO-9) is added, and the mixture is emulsified at 90℃ and 800 r / min for 20 min to prepare a rosin emulsion. Next, the rosin emulsion and polyadipate-hydroxyapatite complex are added to a dispersion vessel, heated to 50℃, and stirred at 600 r / min for 20 min. Then, modified diatomaceous earth, phytosterols, aluminum naphthenate, and deionized water are added sequentially, and the mixture is heated to 65℃ and dispersed at 1200 r / min for 40 min. Then, the mixture is cooled to 45℃, and modified alkyl glycosides, potassium borate, and modified polyglycerol fatty acid ester-calcium stearate complex are added, and stirred at 800 r / min for 25 min. Finally, the mixture is sand-milled, filtered through a 200-mesh sieve, and degassed under vacuum at 0.08 MPa for 15 min to obtain the finished coating.

[0031] Example 2 Compared to Example 1, only the parameters mentioned below have been adjusted; the unadjusted parameters are the same as in Example 1: 1. Preparation of non-commercially available components.

[0032] (1) Modified diatomaceous earth: The materials are taken in a mass ratio of diatomaceous earth, silane coupling agent KH550 and aluminum tripolyphosphate of 100:1.5:15.

[0033] (2) Modified alkyl glycosides: Take 3% of the mass of potassium borate as alkyl glycosides.

[0034] (3) Polyadipate-hydroxyapatite composite: The materials were taken at a mass ratio of 4:1 between polyadipate and hydroxyapatite.

[0035] (4) Modified polyglycerol fatty acid ester-calcium stearate complex: The materials are taken in a mass ratio of polyglycerol fatty acid ester, calcium stearate and cage-type silsesquioxane of 3:1:0.1.

[0036] 2. Coating preparation: Take 30 parts by weight of modified diatomaceous earth, 8 parts by weight of phytosterol, 5 parts by weight of aluminum naphthenate, 3 parts by weight of modified alkyl glycoside, 10 parts by weight of hydrogenated rosin, 20 parts by weight of polyadipate-hydroxyapatite complex, 3 parts by weight of potassium borate, 2 parts by weight of modified polyglycerol fatty acid ester-calcium stearate complex and 18 parts by weight of deionized water.

[0037] Example 3 Compared to Example 1, only the parameters mentioned below have been adjusted; the unadjusted parameters are the same as in Example 1: 1. Preparation of non-commercially available components (1) Modified diatomaceous earth: The materials were taken in a mass ratio of diatomaceous earth, silane coupling agent KH550 and aluminum tripolyphosphate of 100:3:25. During the preparation process, the calcination conditions were changed to 140℃ for 60 min, while the other parameters remained unchanged.

[0038] (2) Modified alkyl glycosides: The amount of potassium borate was 6% of the mass of the alkyl glycoside, and the rest of the preparation was the same as in Example 1.

[0039] (3) Polyadipate-hydroxyapatite composite: The materials were prepared in the same way as in Example 1, with a mass ratio of polyadipate to hydroxyapatite of 6:1.

[0040] (4) Modified polyglycerol fatty acid ester-calcium stearate complex: The polyglycerol fatty acid ester, calcium stearate and cage-type silsesquioxane were prepared in a mass ratio of 5:1:0.3, and the rest of the preparation was the same as in Example 1.

[0041] 2. Coating preparation: Take 40 parts by weight of modified diatomaceous earth, 12 parts by weight of phytosterol, 8 parts by weight of aluminum naphthenate, 5 parts by weight of modified alkyl glycoside, 15 parts by weight of hydrogenated rosin, 25 parts by weight of polyadipate-hydroxyapatite complex, 5 parts by weight of potassium borate, 4 parts by weight of modified polyglycerol fatty acid ester-calcium stearate complex and 22 parts by weight of deionized water.

[0042] Comparative Example 1 Compared with Example 1, only the modified diatomaceous earth was replaced with an equal mass of unmodified diatomaceous earth, while the other raw material ratios and preparation processes were the same as in Example 1.

[0043] Comparative Example 2 Compared with Example 1, the roasting and aging process was omitted in the preparation of modified diatomaceous earth, while the remaining raw material ratios and preparation processes were the same as in Example 1.

[0044] Comparative Example 3 Compared with Example 1, the aluminum tripolyphosphate complexation process was omitted in the preparation of modified diatomaceous earth, while the remaining raw material ratios and preparation processes were the same as in Example 1.

[0045] Comparative Example 4 Compared with Example 1, only the polyadipate-hydroxyapatite composite was replaced with an equal mass of pure polyadipate, while the other raw material ratios and preparation processes were the same as in Example 1.

[0046] Comparative Example 5 Compared with Example 1, only the modified alkyl glycoside was replaced with an equal mass of unmodified alkyl glycoside, while the other raw material ratios and preparation processes were the same as in Example 1.

[0047] Comparative Example 6 Compared with Example 1, only the modified polyglycerol fatty acid ester-calcium stearate complex was replaced with an equal mass of unmodified polyglycerol fatty acid ester-calcium stearate complex (melt blending only, without adding cage-like silsesquioxanes), while the other raw material ratios and preparation processes were the same as in Example 1.

[0048] Comparative Example 7 Compared with Example 1, the phytosterol component was directly removed, while the remaining raw material ratios and preparation processes were the same as in Example 1.

[0049] Experimental Example The coatings prepared in Examples 1-3 and Comparative Examples 1-7 were uniformly coated onto the surface of Q235 ordinary carbon steel substrates, with substrate dimensions uniformly set at 100 mm × 100 mm × 3 mm. A spray coating process was used, controlling the dry film thickness to 500 μm with an error range of ±20 μm. After coating, the samples were placed in a cleanroom environment with a temperature of 25℃, relative humidity of 50%, and a cleanliness level of 10,000 for 7 days. After the coating was fully cured, the following performance tests were conducted. All performance tests were repeated three times, and the average value was taken. The test results are shown in Table 1.

[0050] (1) Wear resistance stability and dust release test (dry accelerated friction method): A reciprocating wear resistance testing machine was used. The test environment was room temperature 25℃, dry and without lubrication. A 45# steel friction head was selected, with a contact area of ​​1 cm². The test load was set to 5 N, the reciprocating speed to 100 times / min, and the reciprocating stroke to 50 mm. 10,000 reciprocating friction cycles were performed continuously. After the test, the mass difference of the sample before and after the test was weighed using a precision electronic balance (accuracy 0.1 mg) to calculate the coating wear rate.

[0051] (2) Low precipitation performance test (isotropic accelerated precipitation method): The sample to be tested was suspended in a clean, sealed glass container with a volume of 5 L and placed in a 60℃ constant temperature oven for 24 h to simulate long-term use and the micro-heat conditions in the workshop, thereby accelerating the evaluation of the tendency of small molecules to precipitate from the coating. After the heat preservation was completed, the condensate on the inner wall of the container and the precipitate on the sample surface were collected and weighed using a precision electronic balance (accuracy 0.1 mg) to calculate the total precipitation rate (total mass of precipitate / initial mass of coating × 100%).

[0052] (3) Antistatic performance and dust adsorption test: ① Antistatic performance: Using a high resistivity meter, the surface resistivity of the coating was tested at room temperature of 25℃ and relative humidity of 50%. The test voltage was 500 V. Three different locations were tested for each sample, and the average value was taken. ② Dust adsorption performance: The sample was placed horizontally in a dust test chamber. 0.1-1 μm submicron talc powder was introduced into the chamber, and the dust concentration was controlled at 10 mg / m³. The sample was left to stand for 24 h at 25℃ and relative humidity of 50%. After the test, the surface dust of the sample was gently swept with a soft brush. The mass difference of the sample before and after the test was weighed using a precision electronic balance (accuracy 0.1 mg) to calculate the amount of dust adsorbed.

[0053] (4) Dry-state anti-adhesion performance test (constant temperature and pressure method): Take two identical test samples, with the coated surfaces facing each other, apply a uniform pressure of 1 kg / cm², and place them in a constant temperature oven at 50℃ for 24 h to simulate long-term contact conditions and accelerate the evaluation of the coating's anti-adhesion tendency. After the heat preservation period, allow them to cool naturally to room temperature, and use a tensile testing machine to peel them at a uniform speed of 50 mm / min. Record the maximum peel force and convert it into peel strength (N / cm).

[0054] (5) Coating adhesion test (pull-off method): Performed in accordance with the standard of "Pull-off Adhesion Test of Paints and Varnishes". A metal test column with a diameter of 20 mm was attached to the coating surface and cured with high-strength adhesive for 24 h. The coating was then stretched at a uniform speed at room temperature of 25℃ using a pull-off adhesion tester. The maximum tensile force at which the coating was damaged was recorded and the adhesion strength (MPa) was calculated.

[0055] Table 1: Performance Test Results As can be seen from Table 1: Examples 1-3 show that, under the synergistic effect of modified diatomaceous earth, polyadipate-hydroxyapatite, and modified alkyl glycosides, the prepared coatings exhibited wear rates ≤3.5 mg / 10⁻⁶. 4Secondly, it exhibits good dry-state wear resistance and low dust release; the total exudation rate is ≤0.92%, with a low level of small molecule exudation, which can reduce the risk of gas release pollution in the vacuum chamber; the surface resistivity is ≤3.1×10⁻⁶. 8 Ω cm, within the antistatic range suitable for clean environments, dust adsorption capacity ≤0.24 mg / cm², with a balanced antistatic and dust suppression adsorption capacity; peel strength ≤3.1 N / cm, good dry-state anti-adhesion performance; adhesion strength ≥4.0 MPa, the coating is firmly bonded to the substrate and has strong structural stability. Overall, it can be adapted to high-cleanliness, lubrication-free dry-state conveying conditions for columnar metal parts, effectively reducing the risk of workpiece scratches, contamination and vacuum system gas release.

[0056] In Comparative Example 1, the unmodified diatomaceous earth resulted in poor interfacial compatibility and unsealed micropores, leading to increased wear and precipitation rates, increased dust adsorption, and a significant decrease in wear resistance and low precipitation performance. In Comparative Example 2, the modified diatomaceous earth was not calcined and matured, leaving many residual micropores and insufficient cross-linking, resulting in poor wear resistance, high dust adsorption, and easy dust shedding after long-term use. In Comparative Example 3, the modified diatomaceous earth was not subjected to aluminum tripolyphosphate complexation passivation, resulting in insufficient pore sealing, increased precipitates, decreased antistatic stability, and increased risk of gas release in a vacuum environment. In Comparative Example 4, the absence of a hydroxyapatite rigid reinforcing phase resulted in insufficient heat resistance and wear resistance of the coating, and frictional heat accumulation easily softened the coating, leading to an increased wear rate. In Comparative Example 5, the alkyl glycoside was not modified with potassium borate, resulting in high hydrophilic activity and uneven surface resistivity, leading to significant electrostatic enrichment, a substantial increase in dust adsorption, and a decrease in cleanliness assurance capabilities. In Comparative Example 6, the modified polyglycerol fatty acid ester-calcium stearate complex was not coated with cage-like silsesquioxane, making it easy for small molecules to migrate and precipitate, leading to an increase in the total precipitation rate and a greater risk of vacuum gas release. In Comparative Example 7, the lack of phytosterol lubricating components resulted in high dry friction resistance, easy interface adhesion, increased peel strength, and workpiece conveying prone to jamming and surface damage.

Claims

1. A coating for a feeding device used in machining columnar metal parts is characterized in that, Includes the following components by weight: 30-40 parts modified diatomaceous earth, 8-12 parts phytosterols, 5-8 parts aluminum naphthenate, 3-5 parts modified alkyl glycosides, 10-15 parts hydrogenated rosin, 20-25 parts polyadipate-hydroxyapatite complex, 3-5 parts potassium borate, 2-4 parts modified polyglycerol fatty acid ester-calcium stearate complex, and 18-22 parts deionized water; The modified diatomaceous earth is obtained by first modifying diatomaceous earth with a silane coupling agent, then modifying it with aluminum tripolyphosphate complexation passivation, and finally calcining and ripening it. The modified alkyl glycoside is obtained by modifying alkyl glycoside with potassium borate; The modified polyglycerol fatty acid ester-calcium stearate composite is obtained by melt blending polyglycerol fatty acid ester-calcium stearate and then modifying it by coating the surface with cage-type silsesquioxane.

2. The coating for a feeding device for machining columnar metal parts according to claim 1, characterized in that, In the modified diatomaceous earth, the mass ratio of diatomaceous earth, silane coupling agent, and aluminum tripolyphosphate is 100:(1.5-3):(15-25).

3. The coating for a feeding device for machining columnar metal parts according to claim 2, characterized in that, The roasting and aging temperature is 120-140℃, and the time is 40-60 minutes.

4. The coating for a feeding device for machining columnar metal parts according to claim 1, characterized in that, In the polyadipate-hydroxyapatite composite, the mass ratio of polyadipate to hydroxyapatite is (4-6):

1.

5. The coating for a feeding device for machining columnar metal parts according to claim 1, characterized in that, In the modified polyglycerol fatty acid ester-calcium stearate composite, the mass ratio of polyglycerol fatty acid ester, calcium stearate, and cage-like silsesquioxane is (3-5):1:(0.1-0.3).

6. The coating for a feeding device for machining columnar metal parts according to claim 1, characterized in that, Potassium borate has a particle size of 600–800 mesh, while diatomaceous earth has a particle size of 800–1200 mesh.

7. The coating for a feeding device for machining columnar metal parts according to claim 1, characterized in that, In the modified alkyl glycoside, the amount of potassium borate is 3% to 6% of the mass of the alkyl glycoside.

8. A method for preparing the coating for a feeding device for machining columnar metal parts as described in any one of claims 1-7, characterized in that, Hydrogenated rosin and polyadipate-hydroxyapatite complex are added to a dispersion vessel, heated to 40-60℃, stirred and dispersed, and then modified diatomaceous earth, phytosterol, aluminum naphthenate, and deionized water are added in sequence. The temperature is raised to 55-75℃, dispersed, and then cooled to 40-50℃. Modified alkyl glycoside, potassium borate, and modified polyglycerol fatty acid ester-calcium stearate complex are added, stirred and dispersed, and then ground, filtered, and vacuum degassed to obtain the finished coating.

9. The method for preparing the coating for the feeding device used in machining columnar metal parts according to claim 8, characterized in that: The hydrogenated rosin needs to undergo emulsification treatment before use. Specifically, the hydrogenated rosin is first melted, and then 8% to 12% of its mass of fatty alcohol polyoxyethylene ether is added for emulsification.

Images