A low-temperature rapid-curing powder coating for robotic arms and its preparation method

Abstract

This invention belongs to the field of coating technology and discloses a low-temperature rapid-curing powder coating for robotic arms and its preparation method. The raw materials of the powder coating, by weight, include: 50-70 parts of hydroxyl polyester resin, 6-10 parts of hydroxyl-terminated polyetherimide resin, 15-25 parts of aliphatic isocyanate curing agent, 6-12 parts of a first filler, 3-6 parts of a second filler, 0.5-1.5 parts of a leveling agent, and 0.3-0.8 parts of a defoamer. The first filler comprises a core and a shell. The core includes zinc-aluminum hydrotalcite and chopped fibers, with the chopped fibers intercalated into the zinc-aluminum hydrotalcite. The shell is a titanate coupling agent. The second filler is ceramic whiskers modified by grafting carboxyl-terminated polyester. This invention provides a low-temperature rapid-curing powder coating suitable for the needs of robotic arms, achieving a synergistic balance between the coating's low-temperature rapid curing characteristics and its comprehensive properties such as high strength, high toughness, excellent wear resistance, and adhesion.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, and specifically relates to a low-temperature rapid curing powder coating for robotic arms and its preparation method. Background Technology

[0002] As a core execution component in the field of intelligent manufacturing, the surface of the metal substrate of the robotic arm usually needs to be coated with powder coating to achieve protective effects such as corrosion resistance, wear resistance, and impact resistance, so as to ensure the long-term stable operation of the robotic arm under high-frequency and high-precision motion conditions.

[0003] Currently, powder coatings used in robotic arms face numerous technical bottlenecks. Conventional low-temperature curing powder coatings often require the introduction of large amounts of flexible resins or toughening components to achieve low-temperature cross-linking properties. This leads to insufficient coating rigidity, making the coating prone to deformation and wear during repeated robotic arm movements, failing to meet the requirements of precision robotic arm components. On the other hand, hard powder coatings, which emphasize mechanical properties, generally suffer from excessively high curing temperatures. High-temperature curing processes can easily damage the thin-walled metal substrate or pre-treatment coating of the robotic arm, affecting the mechanical properties and service life of the substrate. To improve the mechanical properties of the coating, some technical solutions add inorganic fillers to the powder coating. However, traditional inorganic fillers have poor compatibility with the resin matrix, and direct addition can easily lead to filler agglomeration and uneven dispersion, resulting in interface defects within the coating. Under impact or bending, these fillers are prone to cracking and peeling, making it difficult to form a stable protective layer. At the same time, existing technologies for modifying inorganic fillers are relatively simple, often employing simple coupling agent coating treatments. These methods fail to establish strong interactions between the filler and the resin matrix, making it difficult to improve the overall performance of the coating through synergistic effects. Furthermore, the limited crosslinking density of a single resin system makes it difficult to form a dense three-dimensional network structure, which cannot simultaneously meet the requirements of low-temperature rapid curing characteristics and high strength and toughness of the coating, thus restricting the further application of powder coatings in the field of robotic arms. Summary of the Invention

[0004] The present invention aims to improve at least one technical problem in the prior art.

[0005] The first aspect of this invention provides a low-temperature rapid-curing powder coating for robotic arms, comprising the following raw materials by weight: 50-70 parts of hydroxyl polyester resin, 6-10 parts of hydroxyl-terminated polyetherimide resin, 15-25 parts of aliphatic isocyanate curing agent, 6-12 parts of first filler, 3-6 parts of second filler, 0.5-1.5 parts of leveling agent, and 0.3-0.8 parts of defoamer; The first filler includes a core and a shell. The core includes zinc aluminum hydrotalcite and chopped fibers. The chopped fibers are intercalated into the zinc aluminum hydrotalcite. The shell is a titanate coupling agent. The second filler is a ceramic whisker that has been modified by grafting carboxyl-terminated polyester.

[0006] The low-temperature rapid-curing powder coating for robotic arms provided in this application uses hydroxyl polyester resin as the main film-forming substance, which can impart basic mechanical properties and cross-linking reactivity to the coating. An aliphatic isocyanate curing agent, as a cross-linking component, can react with the hydroxyl groups in the resin matrix to achieve low-temperature curing of the coating, balancing curing efficiency and substrate performance protection. The first filler adopts a core-shell structure design. The core consists of zinc-aluminum hydrotalcite (ZALT) and chopped fibers. ZALT, as a layered matrix, provides stable intercalation space for the chopped fibers. Its layered structure also improves the coating's weather resistance and dimensional stability. The chopped fibers intercalate into the interlayer voids of ZALT, leveraging the support of the layered structure to provide skeletal reinforcement, significantly improving the coating's impact resistance and toughness. A titanate coupling agent forms a shell layer; one end of its molecular chain can bind to the active groups on the surface of ZALT and chopped fibers, while the other end can react with the functional groups of the resin matrix, effectively improving the compatibility between the inorganic filler and the organic resin matrix, reducing interface defects, and preventing filler agglomeration. The second filler is a ceramic whisker modified with terminal carboxyl polyester grafting. The grafted terminal carboxyl polyester segments can form molecular entanglement with the resin matrix, enhancing the interfacial bonding between the filler and the resin. The rigidity of the ceramic whiskers themselves further improves the mechanical strength and wear resistance of the coating. Leveling agents and defoamers, as functional additives, can respectively improve the surface smoothness of the coating and eliminate bubbles generated during the curing process, ensuring the appearance quality and performance of the coating. The hydroxyl-terminated polyether imide resin, as a bridging resin, contains terminal hydroxyl groups that can synergistically react with the hydroxyl groups of the hydroxyl polyester resin to undergo a crosslinking reaction with the aliphatic isocyanate curing agent. At the same time, the imide groups on the molecular chain can form a stable bond with the active groups of the titanate coupling agent in the shell layer of the first filler and the terminal carboxyl polyester segments grafted on the surface of the second filler. The components work synergistically to construct a three-dimensional network. The hydroxyl polyester resin and the hydroxyl-terminated polyetherimide resin first form a basic resin network through the cross-linking effect of the curing agent. The first filler is bonded to the resin network with the help of the shell titanate coupling agent. The intercalated short chopped fibers become rigid support nodes in the network. The end-carboxyl polyester segments on the surface of the second filler are not only molecularly entangled with the resin network, but also connected to the first filler through the bridging effect of the hydroxyl-terminated polyetherimide resin. Finally, a dense three-dimensional network is formed in which the resin matrix and the two fillers are closely interwoven and mutually anchored. This allows the powder coating to have both the characteristics of low-temperature rapid curing and the ability to form a high-strength and high-toughness coating that meets the requirements of robotic arms.

[0007] Preferably, the mass ratio of the zinc-aluminum hydrotalcite, the chopped fiber, and the titanate coupling agent is (60-75):(20-30):(5-10).

[0008] Preferably, the chopped fibers include at least one of chopped glass fibers, chopped basalt fibers, and chopped quartz fibers.

[0009] Preferably, the titanate coupling agent comprises at least one of isopropyl dioleoyloxy (dioctylphosphoyloxy) titanate, isopropyl tris (dioctyl pyrophosphoyloxy) titanate, isopropyl tris (dioctyl phosphoyloxy) titanate, tetraisopropyl di (dioctyl phosphite) titanate, and bis(dioctyloxy pyrophosphoyl) ethylene titanate.

[0010] The preparation method of the first filler described above includes the following steps: The zinc-aluminum hydrotalcite and lignin sulfonate were dispersed in water, the pH was adjusted to 9-10, and the mixture was stirred at 60℃-80℃ for 1-2 hours. Then the short-cut fibers were added, and the mixture was ultrasonically dispersed at 80℃-90℃ for 3-4 hours. The mixture was filtered, and the solid product was washed and dried to obtain the core. The core is added to an ethanol solution of the titanate coupling agent, stirred at 50℃-60℃ for 2-3 hours, filtered, and the solid obtained is dried to obtain the first filler.

[0011] It should be noted that in the preparation of the first filler, the alkaline environment promotes the full ionization of the sulfonic acid groups on the lignin sulfonate molecular chain into negatively charged anions. These anions can undergo ion exchange reactions with the anions originally present in the interlayer of zinc-aluminum hydrotalcite, thereby effectively widening the interlayer spacing of zinc-aluminum hydrotalcite and facilitating the subsequent insertion of chopped fibers into the interlayer voids. After the addition of chopped fibers, the polar groups such as hydroxyl groups on the lignin sulfonate molecular chain can undergo physical adsorption and hydrogen bonding with the active groups on the surface of the chopped fibers, acting as a connecting bridge between zinc-aluminum hydrotalcite and chopped fibers, reducing the interfacial tension between them, and guiding the chopped fibers to be uniformly dispersed and embedded in the widened hydrotalcite interlayer.

[0012] Preferably, the grafting rate of the end-carboxyl polyester is 25%-40%.

[0013] Preferably, the ceramic whiskers include at least one of silicon carbide whiskers, silicon nitride whiskers, and alumina whiskers.

[0014] The preparation method of the second filler described above includes the following steps: The ceramic whiskers were ultrasonically dispersed in xylene solvent, and then the carboxyl-terminated polyester and initiator were added. The mixture was reacted at 85°C-95°C for 4-6 hours under a nitrogen atmosphere. After filtration, the solid product was dried to obtain the second filler.

[0015] Preferably, the particle size of the first filler is 5μm-20μm, and the particle size of the second filler is 1μm-5μm.

[0016] Preferably, the aliphatic isocyanate curing agent comprises one of ε-caprolactam-blocked HDI trimer, ε-caprolactam-blocked IPDI trimer, phenol-blocked HDI trimer, and butanone oxime-blocked HDI biuret.

[0017] Preferably, the leveling agent includes at least one of leveling agent F-400, leveling agent F-401, and leveling agent DH 4036.

[0018] Preferably, the defoaming agent includes at least one of benzoin, polyether-modified polysiloxane defoaming agent, and organosilicone defoaming agent.

[0019] A second aspect of this invention provides a method for preparing the aforementioned low-temperature rapid-curing powder coating for robotic arms, comprising the following steps: The raw materials are added to a high-speed mixer and stirred, then fed into a twin-screw extruder through a feed port for melt extrusion, cooling, tableting, crushing, and sieving to obtain the low-temperature rapid-curing powder coating for robotic arms.

[0020] The stirring speed is 500rpm-700rpm, and the time is 5min-10min.

[0021] The melt extrusion temperature is 100℃-110℃, and the screw speed is 250rpm-350rpm.

[0022] The beneficial effects of this invention are as follows: This invention provides a low-temperature, rapid-curing powder coating suitable for the needs of robotic arms, achieving a synergistic balance between the coating's low-temperature rapid-curing characteristics and its comprehensive properties such as high strength, high toughness, excellent wear resistance, and adhesion. This invention relies on the skeletal reinforcement effect of the core-shell intercalation structure of the first filler, the interfacial compatibility and rigidity enhancement effect of the end-carboxyl polyester graft modification of the second filler, and the bridging and cross-linking effect of the end-hydroxyl polyetherimide resin. This allows a dense and stable three-dimensional network structure to be formed between the resin matrix and the inorganic filler, significantly improving the interfacial bonding force and comprehensive mechanical properties of the coating. This results in a coating with excellent impact resistance, bending resistance, and wear resistance, suitable for the high-frequency, high-precision operation conditions of robotic arms, ensuring the stability and protective properties of the coating for long-term use. The comprehensive performance of the coating meets the professional application requirements of robotic arms, significantly enhancing the application value of powder coatings in the field of robotic arm protection in intelligent manufacturing, and possessing good technical practicality and scalability. Detailed Implementation

[0023] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the description of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims. Example 1

[0024] A low-temperature rapid-curing powder coating for robotic arms comprises the following raw materials by weight: 60 parts of hydroxyl polyester resin, 8 parts of hydroxyl-terminated polyetherimide resin, 20 parts of aliphatic isocyanate curing agent (ε-caprolactam-blocked HDI trimer), 10 parts of first filler, 5 parts of second filler, 1 part of leveling agent (leveling agent F-400), and 0.5 parts of defoamer (benzoin).

[0025] The first filler comprises a core and a shell. The core consists of zinc-aluminum hydrotalcite and chopped glass fibers, with the chopped glass fibers intercalated into the zinc-aluminum hydrotalcite. The shell is isopropyltris(dioctylpyrophosphate)titanate. The mass ratio of zinc-aluminum hydrotalcite, chopped glass fibers, and isopropyltris(dioctylpyrophosphate)titanate is 70:25:5. The preparation method of the first filler includes the following steps: dispersing zinc-aluminum hydrotalcite and sodium lignin sulfonate in water, adjusting the pH to 9.5, stirring at 70°C for 1.5 h, then adding chopped glass fibers, ultrasonically dispersing for 15 min, stirring at 85°C for 3.5 h, filtering, washing and drying the solid product to obtain the core; adding the core to an ethanol solution of 3% isopropyltris(dioctylpyrophosphate)titanate, stirring at 55°C for 2.5 h, filtering, drying the solid product to obtain the first filler; the particle size of the first filler is 10 μm.

[0026] The second filler is silicon carbide whiskers grafted with carboxyl-terminated polybutylene terephthalate, with a grafting rate of 35%. The preparation method of the second filler includes the following steps: adding silicon carbide whiskers to xylene solvent and ultrasonically dispersing for 20 min, then adding carboxyl-terminated polybutylene terephthalate and an initiator (benzoyl peroxide), reacting at 90°C for 5 h under a nitrogen atmosphere, filtering, taking the solid product and drying to obtain the second filler; the particle size of the second filler is 3 μm.

[0027] The method for preparing low-temperature rapid-curing powder coating for this robotic arm includes the following steps: The raw materials are added to a high-speed mixer and mixed (mixing speed is 600 rpm, time is 6 min). Then, they are fed into a twin-screw extruder through the feed port for melt extrusion (melt extrusion temperature is 105℃, screw speed is 300 rpm). After cooling, the material is pressed into sheets, crushed, and sieved to obtain a low-temperature rapid curing powder coating for robotic arms. Example 2

[0028] A low-temperature rapid-curing powder coating for robotic arms comprises the following raw materials by weight: 55 parts of hydroxyl polyester resin, 7 parts of hydroxyl-terminated polyetherimide resin, 18 parts of aliphatic isocyanate curing agent (butanone oxime-blocked HDI biuret), 8 parts of first filler, 4 parts of second filler, 0.8 parts of leveling agent (leveling agent F-400), and 0.4 parts of defoamer (benzoin).

[0029] The first filler comprises a core and a shell. The core consists of zinc-aluminum hydrotalcite and chopped basalt fibers, with the chopped fibers intercalated into the zinc-aluminum hydrotalcite. The shell is bis(dioctyloxypyrophosphate) ethylene titanate. The mass ratio of zinc-aluminum hydrotalcite, chopped basalt fibers, and bis(dioctyloxypyrophosphate) ethylene titanate is 65:28:7. The preparation method of the first filler includes the following steps: dispersing zinc-aluminum hydrotalcite and sodium lignosulfonate in water, adjusting the pH to 9, stirring at 65°C for 2 hours, then adding chopped basalt fibers, ultrasonically dispersing for 15 minutes, stirring at 80°C for 4 hours, filtering, washing and drying the solid product to obtain the core; adding the core to an ethanol solution of 4% bis(dioctyloxypyrophosphate) ethylene titanate, stirring at 50°C for 3 hours, filtering, and drying the solid product to obtain the first filler; the particle size of the first filler is 8 μm.

[0030] The second filler is silicon nitride whiskers grafted with carboxyl-terminated polybutylene terephthalate, with a grafting rate of 30%. The preparation method of the second filler includes the following steps: adding silicon nitride whiskers to xylene solvent and ultrasonically dispersing for 25 min, then adding carboxyl-terminated polybutylene terephthalate and an initiator (benzoyl peroxide), reacting at 85°C for 6 h under a nitrogen atmosphere, filtering, taking the solid product and drying to obtain the second filler; the particle size of the second filler is 2 μm.

[0031] The method for preparing low-temperature rapid-curing powder coating for this robotic arm includes the following steps: The raw materials are added to a high-speed mixer and mixed (mixing speed is 550 rpm, time is 5 min). Then, they are fed into a twin-screw extruder through the feed port for melt extrusion (melt extrusion temperature is 100℃, screw speed is 280 rpm). After cooling, the material is pressed into sheets, crushed, and sieved to obtain a low-temperature rapid curing powder coating for robotic arms. Example 3

[0032] A low-temperature rapid-curing powder coating for robotic arms comprises the following raw materials by weight: 70 parts of hydroxyl polyester resin, 10 parts of hydroxyl-terminated polyetherimide resin, 25 parts of aliphatic isocyanate curing agent (ε-caprolactam-blocked IPDI trimer), 12 parts of first filler, 6 parts of second filler, 1.5 parts of leveling agent (leveling agent F-400), and 0.8 parts of defoamer (benzoin).

[0033] The first filler comprises a core and a shell. The core consists of zinc-aluminum hydrotalcite and chopped quartz fibers, with the chopped fibers intercalated into the zinc-aluminum hydrotalcite. The shell is isopropyl dioleoyloxy (dioctyl phosphate oxy) titanate. The mass ratio of zinc-aluminum hydrotalcite, chopped quartz fibers, and isopropyl dioleoyloxy (dioctyl phosphate oxy) titanate is 75:20:5. The preparation method of the first filler includes the following steps: dispersing zinc-aluminum hydrotalcite and sodium lignin sulfonate in water, adjusting the pH to 10, stirring at 75°C for 1 hour, then adding chopped quartz fibers, ultrasonically dispersing for 20 minutes, stirring at 90°C for 3 hours, filtering, washing and drying the solid product to obtain the core; adding the core to an ethanol solution of 5% isopropyl dioleoyloxy (dioctyl phosphate oxy) titanate, stirring at 60°C for 2 hours, filtering, drying the solid product to obtain the first filler; the particle size of the first filler is 15 μm.

[0034] The second filler is alumina whiskers grafted with carboxyl-terminated polybutylene terephthalate (PPT), with a grafting rate of 40%. The preparation method of the second filler includes the following steps: alumina whiskers are ultrasonically dispersed in xylene solvent for 18 min, then PPT and initiator (benzoyl peroxide) are added, and the mixture is reacted at 95 °C for 4 h under a nitrogen atmosphere. After filtration, the solid product is dried to obtain the second filler. The particle size of the second filler is 5 μm.

[0035] The method for preparing low-temperature rapid-curing powder coating for this robotic arm includes the following steps: The raw materials are added to a high-speed mixer and mixed (mixing speed is 700 rpm, time is 10 min). Then, they are fed into a twin-screw extruder through the feed port for melt extrusion (melt extrusion temperature is 110℃, screw speed is 350 rpm). After cooling, the material is pressed into sheets, crushed, and sieved to obtain a low-temperature rapid curing powder coating for robotic arms. Example 4

[0036] A low-temperature, rapid-curing powder coating for robotic arms differs from Example 1 in that the mass ratio of zinc-aluminum hydrotalcite, chopped glass fiber, and isopropyltris(dioctylpyrophosphate)titanate is 80:15:5. Everything else is the same as in Example 1. Example 5

[0037] A low-temperature, rapid-curing powder coating for robotic arms differs from Example 1 in that the mass ratio of zinc-aluminum hydrotalcite, chopped glass fiber, and isopropyltris(dioctylpyrophosphate)titanate is 55:40:10. Everything else is the same as in Example 1. Example 6

[0038] A low-temperature, rapid-curing powder coating for robotic arms differs from Example 1 in that the mass ratio of zinc-aluminum hydrotalcite, chopped glass fiber, and isopropyltris(dioctylpyrophosphate)titanate is 60:25:20. Everything else is the same as in Example 1. Example 7

[0039] A low-temperature, rapid-curing powder coating for robotic arms differs from Example 1 in that the grafting rate of carboxyl-terminated polybutylene terephthalate is 20%. All other aspects are the same as in Example 1. Example 8

[0040] A low-temperature, rapid-curing powder coating for robotic arms differs from Example 1 in that the grafting rate of carboxyl-terminated polybutylene terephthalate is 45%. All other aspects are the same as in Example 1. Comparative Example 1

[0041] A powder coating differs from Example 1 in that it does not contain the first filler in its raw materials. Otherwise, it is the same as Example 1. Comparative Example 2

[0042] A powder coating differs from Example 1 in that it does not contain a second filler in its raw materials. Otherwise, it is the same as Example 1. Comparative Example 3

[0043] A powder coating differs from Example 1 in that it does not contain hydroxyl-terminated polyetherimide resin in its raw materials. Otherwise, it is the same as Example 1. Comparative Example 4

[0044] A powder coating differs from Example 1 in that the first filler does not include a shell layer. Otherwise, it is the same as Example 1. Comparative Example 5

[0045] A powder coating differs from Example 1 in that the core of the first filler is zinc-aluminum hydrotalcite. Otherwise, it is the same as Example 1. Comparative Example 6

[0046] A powder coating differs from Example 1 in that the core of the first filler is aluminum hydroxide. Otherwise, it is the same as Example 1. Comparative Example 7

[0047] A powder coating differs from Example 1 in that the shell layer of the first filler is γ-aminopropyltriethoxysilane. Otherwise, it is the same as Example 1. Comparative Example 8

[0048] A powder coating differs from Example 1 in that the second filler is silicon carbide whiskers. Otherwise, it is the same as Example 1. Comparative Example 9

[0049] A powder coating differs from Example 1 in that the second filler is silicon carbide whiskers grafted with polyacrylate resin. Otherwise, it is the same as Example 1.

[0050] The coatings prepared in the examples and comparative examples were sprayed onto the surface of the substrate, and the performance of the coatings obtained after curing was tested, as shown in Table 1.

[0051] Table 1

[0052] Referring to the data in Table 1, compared with Example 1, Comparative Example 1, due to the absence of the first filler, lost the skeletal support and interfacial anchoring effect provided by the core-shell intercalation filler. The resin matrix lacked an effective inorganic reinforcing phase, directly leading to a significant decrease in the coating's mechanical strength, toughness, and wear resistance. Adhesion also deteriorated significantly, making it unable to withstand the impact and bending during the robot's movements. Comparative Example 2, lacking the second filler, lacked the rigidity reinforcement and wear resistance of ceramic whiskers. Although it retained the skeletal support of the first filler, its overall hardness and wear resistance decreased significantly, and its toughness weakened considerably. While its performance was better than Comparative Example 1, it fell far short of the excellent level of Example 1. Comparative Example 3, lacking the addition of terminal hydroxyl polyetherimide resin, lost the cross-linking effect of the resin as a bridge. The resin matrix and filler could not form a tight bond, resulting in the resin and filler failing to effectively construct a dense three-dimensional network structure. The overall mechanical properties and toughness of the coating significantly deteriorated. In Comparative Example 4, the first filler lacked a shell layer coated with titanate coupling agent, significantly reducing the compatibility between the inorganic core and the organic resin matrix. This resulted in a substantial increase in interfacial defects, leading to a marked decrease in coating adhesion and toughness, and weakening of wear resistance due to the reduced interfacial bonding. In Comparative Example 5, the first filler core did not undergo chopped fiber intercalation. The reinforcing effect of the chopped fibers could not be fully realized thanks to the layered structure of the zinc-aluminum hydrotalcite. While the coating's impact strength and toughness were slightly better than in Comparative Example 4, they were still far lower than in Example 1, clearly demonstrating the crucial role of the intercalation structure in the reinforcing effect of the first filler. Comparative Example 6 lacked both the layered structure of zinc-aluminum hydrotalcite and the synergistic effect of chopped fiber intercalation. The filler was merely a single inorganic powder, resulting in a fundamentally different reinforcing effect compared to the core-shell intercalated first filler of this invention. Ultimately, this led to a significant deterioration in the coating's mechanical properties and toughness, and a substantial decrease in wear resistance. In Comparative Example 7, the shell titanate coupling agent of the first filler was replaced with a silane coupling agent (γ-aminopropyltriethoxysilane). This coupling agent had poor interfacial modification effect on the core composed of zinc-aluminum hydrotalcite and chopped fibers in this invention, failing to effectively improve the bonding force between the inorganic filler and the organic resin. Interfacial defects between the filler and the resin remained, resulting in decreased coating adhesion and toughness, and an inability to form a stable interfacial bond. In Comparative Example 8, the second filler was not modified with end-carboxyl polyester grafting. The compatibility between the ceramic whiskers and the resin matrix was poor, leading to agglomeration and defects within the coating. The stiffness-enhancing effect of the whiskers could not be effectively realized, ultimately resulting in a significant decrease in the coating's adhesion, toughness, and wear resistance. In Comparative Example 9, the grafting material of the second filler was replaced with polyacrylate resin. This resin had poor structural compatibility with the main resin of this invention, and the grafted segments could not form effective molecular entanglement with the main resin. The interfacial bonding force between the filler and the resin was insufficient. This result fully demonstrates the crucial role of end-carboxyl polyester grafting in improving the compatibility and performance of the second filler with the resin matrix.

[0053] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A low-temperature, rapid-curing powder coating for robotic arms, characterized in that, The raw materials, by weight, include: 50-70 parts of hydroxyl polyester resin, 6-10 parts of hydroxyl-terminated polyetherimide resin, 15-25 parts of aliphatic isocyanate curing agent, 6-12 parts of first filler, 3-6 parts of second filler, 0.5-1.5 parts of leveling agent, and 0.3-0.8 parts of defoamer; The first filler includes a core and a shell. The core includes zinc aluminum hydrotalcite and chopped fibers. The chopped fibers are intercalated into the zinc aluminum hydrotalcite. The shell is a titanate coupling agent. The second filler is a ceramic whisker that has been modified by grafting carboxyl-terminated polyester.

2. The low-temperature rapid-curing powder coating for robotic arms according to claim 1, characterized in that, The mass ratio of the zinc-aluminum hydrotalcite, the chopped fiber, and the titanate coupling agent is (60-75):(20-30):(5-10).

3. The low-temperature rapid-curing powder coating for robotic arms according to claim 1, characterized in that, The chopped fibers include at least one of chopped glass fibers, chopped basalt fibers, and chopped quartz fibers; And / or, the titanate coupling agent comprises at least one of isopropyl dioleoyloxy (dioctylphosphoyloxy) titanate, isopropyl tris (dioctyl pyrophosphoyloxy) titanate, isopropyl tris (dioctyl phosphoyloxy) titanate, tetraisopropyl di (dioctyl phosphite) titanate, and bis(dioctyloxy pyrophosphoyl) ethylene titanate.

4. The low-temperature rapid-curing powder coating for robotic arms according to claim 1, characterized in that, The preparation method of the first filler includes the following steps: The zinc-aluminum hydrotalcite and lignin sulfonate were dispersed in water, the pH was adjusted to 9-10, and the mixture was stirred at 60℃-80℃ for 1-2 hours. Then the short-cut fibers were added, and the mixture was ultrasonically dispersed at 80℃-90℃ for 3-4 hours. The mixture was filtered, and the solid product was washed and dried to obtain the core. The core is added to an ethanol solution of the titanate coupling agent, stirred at 50℃-60℃ for 2-3 hours, filtered, and the solid obtained is dried to obtain the first filler.

5. The low-temperature rapid-curing powder coating for robotic arms according to claim 1, characterized in that, The grafting rate of the end-carboxyl polyester is 25%-40%.

6. The low-temperature rapid-curing powder coating for robotic arms according to claim 1, characterized in that, The ceramic whiskers include at least one of silicon carbide whiskers, silicon nitride whiskers, and alumina whiskers.

7. The low-temperature rapid-curing powder coating for robotic arms according to claim 1, characterized in that, The particle size of the first filler is 5μm-20μm, and the particle size of the second filler is 1μm-5μm.

8. The low-temperature rapid-curing powder coating for robotic arms according to claim 1, characterized in that, The aliphatic isocyanate curing agent includes one of ε-caprolactam-blocked HDI trimer, ε-caprolactam-blocked IPDI trimer, phenol-blocked HDI trimer, and butanone oxime-blocked HDI biuret.

9. A method for preparing a low-temperature rapid-curing powder coating for a robotic arm as described in any one of claims 1 to 8, characterized in that, Includes the following steps: The raw materials are added to a high-speed mixer and stirred, then fed into a twin-screw extruder through a feed port for melt extrusion, cooling, tableting, crushing, and sieving to obtain the low-temperature rapid-curing powder coating for robotic arms.

10. The method for preparing low-temperature rapid-curing powder coating for robotic arms according to claim 9, characterized in that, The stirring speed is 500rpm-700rpm, and the time is 5min-10min; And / or, the melt extrusion temperature is 100℃-110℃, and the screw speed is 250rpm-350rpm.

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