Multifunctional leveling agent for powder coating preparation

Abstract

The application provides a multifunctional leveling agent for powder coating preparation, and belongs to the technical field of powder coating, and a preparation method thereof comprises the following steps: S1, 80-100 parts of isomeric tridecanol polyoxyethylene ether is dissolved in 200-300 parts of deionized water according to weight parts, 6-10 parts of functional calcium carbonate is added, stirring is carried out for 0.5-1.5 hours, 40 parts of acrylate and 2-4 parts of allyl alcohol polyether are added, and a prepolymer liquid is obtained after uniform stirring; S2, 2-4 parts of 5% sodium persulfate aqueous solution is added into a reaction kettle, the temperature is increased to 55-70 DEG C, 1 / 2 weight of the prepolymer liquid obtained in S1 is added dropwise, the dropwise addition is completed in 1-2 hours, constant temperature reaction is carried out for 0.5-1 hour, and an acrylate polymer is obtained; S3, the remaining prepolymer liquid is added dropwise into the acrylate polymer obtained in S2, the dropwise addition is completed in 1-2 hours, heat preservation is carried out for 2-4 hours, then cooling is carried out to room temperature, and filtration is carried out, so that the multifunctional leveling agent is obtained. The leveling agent can improve the appearance of the powder coating, make the powder coating smooth and uniform, has high corrosion resistance, and effectively improves the corrosion defect problem of the powder coating at the edge and corner positions.

Description

Technical Field

[0001] This invention relates to the field of powder coating technology, and more specifically to a multifunctional leveling agent for powder coating preparation. Background Technology

[0002] Powder coatings are solid powder coatings composed of resins, pigments, fillers, and additives. Unlike conventional coatings, powder coatings do not use solvents during application, making them economical, environmentally friendly, safe, and efficient. Powder coating systems are increasingly favored by the market. Leveling agents are a commonly used additive in powder coatings; they reduce the surface tension of the coating liquid, improve its permeability, and enable the coating to form a smooth and even film during the film-forming process.

[0003] When powder coatings are applied to metal surfaces, the corners and edges are often blind spots for spraying. Even if the corners and edges are properly coated, the fluidity of the coating in those areas will be affected, easily leading to uneven coating thickness. Therefore, the coating at the metal corners and edges is often the first to be corroded, and once corrosion occurs, it will quickly spread over a large area, causing damage to the entire coating.

[0004] The reason why coatings at metal edges and corners are prone to corrosion is related to the corrosion resistance of the coating, as well as the flow properties of the coating. Developing a multifunctional leveling agent that can effectively prevent corrosion and has good flow properties is the key to solving this problem. Summary of the Invention

[0005] The purpose of this invention is to provide a multifunctional leveling agent that can improve the appearance of the coating, make the coating surface smooth and uniform, and also has high corrosion resistance, effectively improving the corrosion defects of powder coatings at the edges and corners.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A multifunctional leveling agent for powder coating preparation, the preparation method of which includes the following steps:

[0008] S1. By weight, dissolve 80-100 parts of isomeric tridecyl alcohol polyoxyethylene ether in 200-300 parts of deionized water, add 6-10 parts of functionalized calcium carbonate, stir for 0.5-1.5 hours, add 40 parts of acrylate and 2-4 parts of allyl alcohol polyether, stir evenly to obtain the prepolymer solution.

[0009] S2. Add 2-4 parts of a 5% sodium persulfate aqueous solution to the reactor, heat to 55-70℃, add 1 / 2 weight of the prepolymer obtained in S1 dropwise, and complete the addition in 1-2 hours. React at a constant temperature for 0.5-1 hours to obtain the acrylate polymer.

[0010] S3. Add the remaining prepolymer solution dropwise to the acrylate polymer obtained in S2. The addition is completed in 1-2 hours. Keep it warm for 2-4 hours, then cool it to room temperature and filter it to obtain the multifunctional leveling agent.

[0011] Furthermore, the acrylate is one or a mixture of at least two of methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate.

[0012] Furthermore, the preparation method of the functionalized calcium carbonate is as follows:

[0013] A1. By weight, 10 parts of sodium carbonate and 18-22 parts of calcium nitrate are placed in a ball mill jar, 0.2-1 parts of N,N-diethylethanolamine are added, the mixture is stirred for 0.5-1 h, ball milled, washed with 50 wt% ethanol aqueous solution, and dried to obtain calcium carbonate.

[0014] A2. Add the calcium carbonate obtained in A1 to 60-80 parts of deionized water and stir evenly to obtain a calcium carbonate suspension. Add 5-7 parts of the modification solution, place in a water bath at 60-80℃, stir for 30-45 minutes, wash, filter and dry to obtain modified calcium carbonate.

[0015] A3. By weight, mix 5 parts modified calcium carbonate, 10-30 parts water and 40-80 parts ethylene glycol butyl ether evenly, then add 0.3-0.6 parts carboxylated carbon nanotubes, sonicate for 10-15 minutes, after sonication, heat to 75-85℃, stir for 15-30 minutes, cool to room temperature to obtain product A, then filter, wash and dry product A to obtain functionalized calcium carbonate.

[0016] Furthermore, by weight, the modified solution is composed of 1 part N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and 20-30 parts 50wt% aqueous ethanol solution.

[0017] Furthermore, it is used to prepare powder coatings, which, by mass percentage, comprise the following raw material components: 20%-30% polyester resin, 15%-25% filler, 2%-4% curing agent, 0.5%-1% benzoin, 0.8%-1.2% of the multifunctional leveling agent, 0.5%-2% pigment, 3%-5% functional additives, and the balance epoxy resin.

[0018] Furthermore, the functional additive is potassium fluorozirconate.

[0019] Furthermore, the filler is one or a mixture of at least two of barium sulfate, kaolin, and bentonite.

[0020] Furthermore, the curing agent is one or a mixture of at least two of diethylenetriamine, diethylaminopropylamine, and m-phenylenediamine.

[0021] Furthermore, the pigment is any one of carbon black, iron black, iron red, chrome yellow, and chrome green.

[0022] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0023] 1. This invention utilizes the interactions between various substances and optimizes the preparation process and component ratio. The powder coating prepared using the leveling agent described in this application not only has excellent flow properties and adhesion strength, but also maintains high corrosion resistance in corrosive environments, thus ensuring the surface quality of the coating is not compromised.

[0024] 2. The leveling agent prepared in this invention introduces inorganic filler calcium carbonate as the carrier of the leveling agent, replacing the conventionally used silica, thereby reducing production costs. In addition, through the effective combination of modified polyacrylate and functionalized calcium carbonate, the obtained leveling agent can effectively improve the adhesion, leveling performance and anti-corrosion performance of powder coatings.

[0025] 3. Functionalized calcium carbonate introduces carbon nanotubes, which provide physical protection to the substrate, making the coating denser and preventing corrosion pits caused by uneven coating thickness distribution, thus further improving the corrosion resistance of powder coatings. Detailed Implementation

[0026] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] Example 1: A method for preparing a multifunctional leveling agent for powder coatings is as follows:

[0028] S1: By weight, 100 parts of isomeric tridecyl alcohol polyoxyethylene ether are dissolved in 250 parts of deionized water, then 8 parts of functionalized calcium carbonate are added and stirred for 1 hour. 40 parts of methyl methacrylate and 3 parts of allyl alcohol polyether are added and stirred evenly to obtain the prepolymer solution.

[0029] S2: Add 3 parts of a 5% sodium persulfate deionized water solution to the reactor, heat to 65°C, add 1 / 2 weight of the prepolymer solution dropwise, and complete the addition in 1 hour. React at a constant temperature for 0.5 hours to obtain the acrylate polymer.

[0030] S3: Add the remaining prepolymer solution dropwise to the acrylate polymer. The addition is completed in 1 hour. Keep it warm for 3 hours, then cool to room temperature and filter to obtain the multifunctional leveling agent.

[0031] The preparation method of functionalized calcium carbonate consists of the following steps:

[0032] A1. By weight, 10 parts of sodium carbonate and 20 parts of calcium nitrate were placed in a ball mill jar, and 0.5 parts of N,N-diethylethanolamine were added. After stirring for 0.5 hours, the mixture was ball milled, washed with 50wt% ethanol aqueous solution, and dried to obtain calcium carbonate.

[0033] A2. The calcium carbonate obtained in this example is added to 70 parts of deionized water and stirred evenly to obtain a calcium carbonate suspension. 6 parts of the modified solution are added, and the mixture is placed in a 70°C water bath and stirred for 30 minutes. The mixture is then washed, filtered, and dried to obtain modified calcium carbonate.

[0034] A3. By weight, mix 5 parts of the modified calcium carbonate obtained in this example, 20 parts of water and 60 parts of ethylene glycol butyl ether evenly, then add 0.5 parts of carboxylated carbon nanotubes, sonicate for 10 minutes, after sonication, heat to 80°C, stir for 20 minutes, cool to room temperature, filter, wash and dry to obtain functionalized calcium carbonate.

[0035] The modified solution is composed of 1 part N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and 25 parts 50wt% aqueous ethanol solution by weight.

[0036] The powder coating is composed of the following raw materials by weight percentage: 25% polyester resin, 20% filler, 3% curing agent, 0.5% benzoin, 1% leveling agent, 0.5% pigment, 4% functional additives, and the balance being epoxy resin.

[0037] The filler is barium sulfate, the curing agent is diethylenetriamine, the pigment is carbon black, the functional additive is potassium fluorozirconate, and the leveling agent is the multifunctional leveling agent obtained in this embodiment.

[0038] The preparation method of the powder coating includes the following steps:

[0039] B1. Take polyester resin, filler, curing agent, benzoin, leveling agent, pigment, functional additives and epoxy resin, and put them into the mixing tank for premixing to obtain a premix;

[0040] B2. The premix is ​​fed into a twin-screw extruder for extrusion, tableting, crushing, and sieving to obtain the powder coating. The final powder coating has a particle size of 25-80 μm.

[0041] Example 2: A method for preparing a multifunctional leveling agent for powder coating is as follows: S1: By weight, 80 parts of isomeric tridecyl alcohol polyoxyethylene ether are dissolved in 200 parts of deionized water, then 6 parts of functionalized calcium carbonate are added and stirred for 1.5 h, then 40 parts of methyl methacrylate and 2 parts of allyl alcohol polyether are added and stirred evenly to obtain a prepolymer solution.

[0042] S2: Add 2 parts of a 5% sodium persulfate deionized water solution to the reactor, heat to 70°C, add 1 / 2 weight of the prepolymer solution dropwise, and complete the addition in 1 hour. React at a constant temperature for 1 hour to obtain the acrylate polymer.

[0043] S3: Add the remaining prepolymer solution dropwise to the acrylate polymer. The addition is completed in 1 hour. Keep it warm for 4 hours, then cool to room temperature and filter to obtain the multifunctional leveling agent.

[0044] The preparation method of functionalized calcium carbonate consists of the following steps:

[0045] A1. By weight, 10 parts of sodium carbonate and 18 parts of calcium nitrate were placed in a ball mill jar, and 0.2 parts of N,N-diethylethanolamine were added. After stirring for 1 hour, the mixture was ball milled, washed with 50wt% ethanol aqueous solution, and dried to obtain calcium carbonate.

[0046] A2. Add the calcium carbonate obtained in this example to 60 parts of deionized water and stir evenly to obtain a calcium carbonate suspension. Add 5 parts of the modification solution, place in an 80°C water bath, stir for 45 minutes, wash, filter and dry to obtain modified calcium carbonate.

[0047] A3. By weight, mix 5 parts of the modified calcium carbonate obtained in this example, 10 parts of water and 40 parts of ethylene glycol butyl ether evenly, then add 0.3 parts of carboxylated carbon nanotubes, sonicate for 10 min, after sonication, heat to 85°C, stir for 15 min, cool to room temperature, filter, wash and dry to obtain functionalized calcium carbonate.

[0048] The modified solution is composed of 1 part N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and 20 parts 50wt% aqueous ethanol solution, by weight.

[0049] The powder coating is composed of the following raw materials by weight percentage: 25% polyester resin, 20% filler, 3% curing agent, 0.5% benzoin, 1% leveling agent, 0.5% pigment, 4% functional additives, and the balance being epoxy resin.

[0050] The filler is kaolin, the curing agent is diethylaminopropylamine, the pigment is iron black, the functional additive is potassium fluorozirconate, and the leveling agent is the multifunctional leveling agent obtained in this embodiment.

[0051] The preparation method of the powder coating includes the following steps:

[0052] B1: Take polyester resin, filler, curing agent, benzoin, leveling agent, pigment, functional additives and epoxy resin, and then put them into a mixing tank for premixing to obtain a premix;

[0053] B2: The premix is ​​fed into a twin-screw extruder and subjected to extrusion, tableting, crushing and sieving in sequence to obtain the powder coating. The final powder coating has a particle size of 25-80μm.

[0054] Example 3: A method for preparing a multifunctional leveling agent for powder coatings is as follows:

[0055] S1: By weight, 100 parts of isomeric tridecyl alcohol polyoxyethylene ether are dissolved in 250 parts of deionized water, then 8 parts of functionalized calcium carbonate are added and stirred for 1 hour. 40 parts of methyl methacrylate and 3 parts of allyl alcohol polyether are added and stirred evenly to obtain the prepolymer solution.

[0056] S2: Add 3 parts of a 5% sodium persulfate deionized water solution to the reactor, heat to 65°C, add 1 / 2 weight of the prepolymer solution dropwise, and complete the addition in 1 hour. React at a constant temperature for 0.5 hours to obtain the acrylate polymer.

[0057] S3: Add the remaining prepolymer solution dropwise to the acrylate polymer. The addition is completed in 1 hour. Keep it warm for 3 hours, then cool to room temperature and filter to obtain the multifunctional leveling agent.

[0058] The preparation method of functionalized calcium carbonate consists of the following steps:

[0059] A1: By weight, 10 parts sodium carbonate and 20 parts calcium nitrate were placed in a ball mill jar, and 0.5 parts N,N-diethylethanolamine were added. After stirring for 0.5 hours, the mixture was ball milled, washed with 50wt% ethanol aqueous solution, and dried to obtain calcium carbonate.

[0060] A2: Add the calcium carbonate obtained in this example to 70 parts of deionized water and stir evenly to obtain a calcium carbonate suspension. Add 6 parts of the modification solution, place in a 70°C water bath, stir for 30 minutes, wash, filter, and dry to obtain modified calcium carbonate.

[0061] A3: By weight, 5 parts of the modified calcium carbonate obtained in this example, 20 parts of water and 60 parts of ethylene glycol butyl ether are mixed evenly, and then 0.5 parts of carboxylated carbon nanotubes are added. The mixture is sonicated for 10 minutes. After sonication, it is heated to 80°C and stirred for 20 minutes. After cooling to room temperature, it is filtered, washed and dried to obtain functionalized calcium carbonate.

[0062] The modified solution is composed of 1 part N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and 25 parts 50wt% aqueous ethanol solution by weight.

[0063] The powder coating is composed of the following raw materials by weight percentage: 25% polyester resin, 20% filler, 3% curing agent, 0.5% benzoin, 1% leveling agent, 0.5% pigment, 4% functional additives, and the balance being epoxy resin.

[0064] The filler is bentonite, the curing agent is m-phenylenediamine, the pigment is iron oxide red, the functional additive is potassium fluorozirconate, and the leveling agent is the multifunctional leveling agent obtained in this embodiment.

[0065] The preparation method of the powder coating is the same as in Example 1.

[0066] Example 4: A method for preparing a multifunctional leveling agent for powder coatings is as follows:

[0067] S1: By weight, 90 parts of isomeric tridecyl alcohol polyoxyethylene ether are dissolved in 250 parts of deionized water, then 7 parts of functionalized calcium carbonate are added and stirred for 1 hour. 40 parts of methyl methacrylate and 3 parts of allyl alcohol polyether are added and stirred evenly to obtain the prepolymer solution.

[0068] S2: Add 3 parts of a 5% sodium persulfate deionized water solution to the reactor, heat to 65°C, add 1 / 2 weight of the prepolymer solution dropwise, and complete the addition in 1 hour. React at a constant temperature for 0.5 hours to obtain the acrylate polymer.

[0069] S3: Add the remaining prepolymer solution dropwise to the acrylate polymer. The addition is completed in 1 hour. Keep it warm for 3 hours, then cool to room temperature and filter to obtain the multifunctional leveling agent.

[0070] The preparation method of functionalized calcium carbonate consists of the following steps:

[0071] A1: By weight, 10 parts of sodium carbonate and 19 parts of calcium nitrate were placed in a ball mill jar, and 0.7 parts of N,N-diethylethanolamine were added. After stirring for 0.5 hours, the mixture was ball milled, washed with 50wt% ethanol aqueous solution, and dried to obtain calcium carbonate.

[0072] A2: Add the calcium carbonate obtained in this example to 65 parts of deionized water and stir evenly to obtain a calcium carbonate suspension. Add 6 parts of the modification solution, place in a 70°C water bath, stir for 30 minutes, wash, filter and dry to obtain modified calcium carbonate.

[0073] A3: By weight, 5 parts of the modified calcium carbonate obtained in this example, 15 parts of water and 50 parts of ethylene glycol butyl ether are mixed evenly, and then 0.4 parts of carboxylated carbon nanotubes are added. The mixture is sonicated for 10 minutes. After sonication, it is heated to 80°C and stirred for 20 minutes. After cooling to room temperature, it is filtered, washed and dried to obtain functionalized calcium carbonate.

[0074] The modified solution is composed of 1 part N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and 25 parts 50wt% aqueous ethanol solution by weight.

[0075] The powder coating is composed of the following raw materials by weight percentage: 25% polyester resin, 20% filler, 3% curing agent, 0.5% benzoin, 1% leveling agent, 0.5% pigment, 4% functional additives, and the balance being epoxy resin.

[0076] The filler is kaolin, the curing agent is diethylaminopropylamine, the pigment is iron black, the functional additive is potassium fluorozirconate, and the leveling agent is the multifunctional leveling agent obtained in this embodiment.

[0077] The preparation method of the powder coating is the same as in Example 1.

[0078] Example 5: A method for preparing a multifunctional leveling agent for powder coatings is as follows:

[0079] S1: By weight, 90 parts of isomeric tridecyl alcohol polyoxyethylene ether are dissolved in 260 parts of deionized water, then 8 parts of functionalized calcium carbonate are added and stirred for 1.5 hours. 40 parts of methyl methacrylate and 4 parts of allyl alcohol polyether are added and stirred evenly to obtain a prepolymer solution.

[0080] S2: Add 4 parts of a 5% sodium persulfate deionized water solution to the reactor, heat to 60°C, add 1 / 2 weight of the prepolymer solution dropwise, and complete the addition in 1.5 h. React at a constant temperature for 1 h to obtain the acrylate polymer.

[0081] S3: Add the remaining prepolymer solution dropwise to the acrylate polymer. The addition is completed in 2 hours. Keep it warm for 4 hours, then cool it to room temperature and filter it to obtain the multifunctional leveling agent.

[0082] The preparation method of functionalized calcium carbonate consists of the following steps:

[0083] A1: By weight, 10 parts of sodium carbonate and 19 parts of calcium nitrate were placed in a ball mill jar, and 1 part of N,N-diethylethanolamine was added. After stirring for 1 hour, the mixture was ball milled, washed with 50wt% ethanol aqueous solution, and dried to obtain calcium carbonate.

[0084] A2: Add the calcium carbonate obtained in this example to 75 parts of deionized water and stir evenly to obtain a calcium carbonate suspension. Add 7 parts of the modification solution, place in an 80°C water bath, stir for 40 minutes, wash, filter, and dry to obtain modified calcium carbonate.

[0085] A3: By weight, 5 parts of the modified calcium carbonate obtained in this example, 25 parts of water and 70 parts of ethylene glycol butyl ether are mixed evenly, and then 0.6 parts of carboxylated carbon nanotubes are added. The mixture is sonicated for 15 minutes. After sonication, it is heated to 85°C and stirred for 30 minutes. After cooling to room temperature, it is filtered, washed and dried to obtain functionalized calcium carbonate.

[0086] The modified solution is composed of 1 part N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and 25 parts 50wt% aqueous ethanol solution by weight.

[0087] The filler is a mixture of barium sulfate and kaolin, with a mass ratio of barium sulfate to kaolin of 1:1. The curing agent is diethylenetriamine, the pigment is iron oxide red, the functional additive is potassium fluorozirconate, and the leveling agent is the multifunctional leveling agent obtained in this embodiment.

[0088] The preparation method of the powder coating is the same as in Example 1.

[0089] Example 6: A method for preparing a multifunctional leveling agent for powder coatings is as follows:

[0090] S1: By weight, dissolve 100 parts of isomeric tridecyl alcohol polyoxyethylene ether in 200 parts of deionized water, then add 9 parts of functionalized calcium carbonate, stir for 1.5 h, add 40 parts of methyl methacrylate and 2 parts of allyl alcohol polyether, stir evenly to obtain the prepolymer solution.

[0091] S2: Add 4 parts of a 5% sodium persulfate deionized water solution to the reactor, heat to 70°C, add 1 / 2 weight of the prepolymer solution dropwise, and complete the addition in 1 hour. React at a constant temperature for 0.5 hours to obtain the acrylate polymer.

[0092] S3: Add the remaining prepolymer solution dropwise to the acrylate polymer. The addition is completed in 1 hour. Keep it warm for 3 hours, then cool to room temperature and filter to obtain the multifunctional leveling agent.

[0093] The preparation method of functionalized calcium carbonate consists of the following steps:

[0094] A1. By weight, 10 parts of sodium carbonate and 21 parts of calcium nitrate were placed in a ball mill jar, and 0.8 parts of N,N-diethylethanolamine were added. After stirring for 0.8 hours, the mixture was ball milled, washed with 50wt% ethanol aqueous solution, and dried to obtain calcium carbonate.

[0095] A2. Add the calcium carbonate obtained in this example to 70 parts of deionized water and stir evenly to obtain a calcium carbonate suspension. Add 7 parts of the modification solution, place in a 70°C water bath, stir for 30 minutes, wash, filter and dry to obtain modified calcium carbonate.

[0096] A3. By weight, 5 parts of the modified calcium carbonate obtained in this example, 30 parts of water and 55 parts of ethylene glycol butyl ether are mixed evenly, and then 0.5 parts of carboxylated carbon nanotubes are added. The mixture is sonicated for 10 minutes. After sonication, it is heated to 80°C and stirred for 20 minutes. After cooling to room temperature, it is filtered, washed and dried to obtain functionalized calcium carbonate.

[0097] The modified solution is composed of 1 part N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and 25 parts 50wt% aqueous ethanol solution by weight.

[0098] The powder coating is composed of the following raw materials by weight percentage: 25% polyester resin, 20% filler, 3% curing agent, 0.5% benzoin, 1% leveling agent, 0.5% pigment, 4% functional additives, and the balance being epoxy resin.

[0099] The filler is a mixture of barium sulfate, kaolin, and bentonite, with a mass ratio of 1:1:1. The curing agent is diethylenetriamine, the pigment is carbon black, the functional additive is potassium fluorozirconate, and the leveling agent is the multifunctional leveling agent obtained in this embodiment.

[0100] The preparation method of the powder coating is the same as in Example 1.

[0101] Comparative Example 1: Unlike Example 1, in the preparation method of the leveling agent in Comparative Example 1, allyl alcohol polyether is not added. Specifically, instead of adding 40 parts of methyl methacrylate and 3 parts of allyl alcohol polyether, 43 parts of methyl methacrylate are added.

[0102] Comparative Example 2: Unlike Example 1, the preparation method of functionalized calcium carbonate in Comparative Example 2 changed the modifying solution. Specifically, the modifying solution was a mixture of 1 part aniline methyltriethoxysilane and 25 parts 50 wt% aqueous ethanol solution.

[0103] Comparative Example 3: Unlike Example 1, in the preparation method of functionalized calcium carbonate in Comparative Example 3, carboxylated carbon nanotubes were replaced with graphene oxide.

[0104] Comparative Example 4: Unlike Example 1, in the preparation method of the leveling agent in Comparative Example 4, allyl alcohol polyether is not added. Specifically, the addition of 40 parts of methyl methacrylate and 3 parts of allyl alcohol polyether is replaced by the addition of 43 parts of methyl methacrylate. In addition, in the preparation method of functionalized calcium carbonate, carboxylated carbon nanotubes are replaced with graphene oxide.

[0105] The corresponding powder coatings were prepared according to the methods described in the examples and comparative examples. The obtained powder coatings were sprayed onto stainless steel plates by electrostatic spraying and then baked for 10 minutes to obtain a dry film thickness of 90 μm. The performance of the coatings in each comparative example and example was tested, and the test results are shown in Table 1.

[0106] 1. Adhesion: Tested according to the test method in GB / T 17748-2016;

[0107] 2. Leveling grade: The leveling grade is based on JB / T 3998-1999, and then compared with the leveling standard comparison board for powder coating. There are 10 standard comparison boards, and the corresponding leveling grades are 1-10, with grade 1 being the worst and grade 10 being the best.

[0108] 3. Corrosion resistance: Salt spray test was conducted according to the test method in national standard GB / T 1771-2007. The time for blistering or peeling of the coating at the edges and corners was observed. The test results are shown in Table 1.

[0109] Table 1

[0110]

[0111]

[0112] According to the adhesion, leveling grade, and salt spray resistance time of the powder coatings in Examples 1-6 in Table 1, it can be seen that the adhesion, leveling grade, and salt spray resistance time of the powder coatings in Examples 1-6 are all excellent.

[0113] In Example 1, the adhesion, leveling grade, and salt spray resistance time of the powder coating were 0, 10, and 488 hours, respectively.

[0114] In Comparative Example 1, the adhesion of the powder coating was grade 2 and the leveling grade was grade 7. In the preparation method of the leveling agent in Comparative Example 1, allyl alcohol polyether was not added, but 43 parts of methyl methacrylate were added. This shows that allyl alcohol polyether can improve the dispersion ability of the leveling agent in the powder coating and the degree of crosslinking with various substances in the powder coating, thereby improving the leveling and adhesion of the powder coating.

[0115] In Comparative Example 2, the leveling grade of the powder coating was 7 and the salt spray resistance time was 416h. In the preparation method of functionalized calcium carbonate in Comparative Example 2, the modifying liquid was a mixture of 1 part aniline methyltriethoxysilane and 25 parts 50wt% ethanol aqueous solution. Compared with Example 1, this shows that the modifying liquid affects the corrosion resistance and leveling grade of the powder coating.

[0116] In Comparative Example 3, the adhesion of the powder coating was 3 and the salt spray resistance time was 393h. Carboxylated carbon nanotubes can improve the dispersion performance of carbon nanotubes and effectively prevent the aggregation of carbon nanotubes. Compared with Example 1, it shows that carboxylated carbon nanotubes can improve the adhesion and salt spray resistance time of the powder coating.

[0117] In Comparative Example 4, the powder coating had an adhesion of 4, a salt spray resistance time of 284, and a leveling grade of 6. Based on Comparative Examples 1, 3, and 1, it can be seen that the participation of allyl alcohol polyether and carboxylated carbon nanotubes in the preparation method of the present invention has a synergistic effect in improving the adhesion, salt spray resistance, and leveling properties of the powder coating.

[0118] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A multifunctional leveling agent for powder coating preparation, characterized in that, Its preparation method includes the following steps: S1. By weight, dissolve 80-100 parts of isomeric tridecyl alcohol polyoxyethylene ether in 200-300 parts of deionized water, add 6-10 parts of functionalized calcium carbonate, stir for 0.5-1.5 hours, add 40 parts of acrylate and 2-4 parts of allyl alcohol polyether, stir evenly to obtain the prepolymer solution. S2. Add 2-4 parts of a 5% sodium persulfate aqueous solution to the reactor, heat to 55-70℃, add 1 / 2 weight of the prepolymer obtained in S1 dropwise, and complete the addition in 1-2 hours. React at a constant temperature for 0.5-1 hours to obtain the acrylate polymer. S3. Add the remaining prepolymer solution dropwise to the acrylate polymer obtained in S2. The addition is completed in 1-2 hours. Keep it warm for 2-4 hours, then cool it to room temperature and filter it to obtain the multifunctional leveling agent. The preparation method of the functionalized calcium carbonate is as follows: A1. By weight, 10 parts of sodium carbonate and 18-22 parts of calcium nitrate are placed in a ball mill jar, 0.2-1 parts of N,N-diethylethanolamine are added, the mixture is stirred for 0.5-1 h, ball milled, washed with 50wt% ethanol aqueous solution, and dried to obtain calcium carbonate. A2. Add the calcium carbonate obtained in A1 to 60-80 parts of deionized water and stir evenly to obtain a calcium carbonate suspension. Add 5-7 parts of the modification solution, place in a water bath at 60-80℃, stir for 30-45 minutes, wash, filter and dry to obtain modified calcium carbonate. A3. By weight, mix 5 parts modified calcium carbonate, 10-30 parts water and 40-80 parts ethylene glycol butyl ether evenly, then add 0.3-0.6 parts carboxylated carbon nanotubes, sonicate for 10-15 min, after sonication, heat to 75-85℃, stir for 15-30 min, cool to room temperature to obtain product A, then filter, wash and dry product A to obtain functionalized calcium carbonate. The modified solution, by weight, is a mixture of 1 part N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane and 20-30 parts 50wt% aqueous ethanol solution.

2. The multifunctional leveling agent for powder coating preparation according to claim 1, characterized in that, The acrylate is one or a mixture of at least two of the following: methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate.

3. A multifunctional leveling agent for powder coating preparation according to claim 1 or 2, characterized in that, It is used to prepare powder coatings, which, by mass percentage, comprise the following raw material components: 20%-30% polyester resin, 15%-25% filler, 2%-4% curing agent, 0.5%-1% benzoin, 0.8%-1.2% of the multifunctional leveling agent, 0.5%-2% pigment, 3%-5% functional additives, and the balance epoxy resin.

4. The multifunctional leveling agent for powder coating preparation according to claim 3, characterized in that, The functional additive is potassium fluorozirconate.

5. The multifunctional leveling agent for powder coating preparation according to claim 3, characterized in that, The filler is one or a mixture of at least two of barium sulfate, kaolin, and bentonite.

6. The multifunctional leveling agent for powder coating preparation according to claim 3, characterized in that, The curing agent is one or a mixture of at least two of diethylenetriamine, diethylaminopropylamine, and m-phenylenediamine.

7. The multifunctional leveling agent for powder coating preparation according to claim 3, characterized in that, The pigment is any one of carbon black, iron black, iron red, chrome yellow, and chrome green.

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