MOFs-based antistatic agent, polyurea coating and preparation method thereof

Abstract

The invention provides an MOFs-based antistatic agent, a polyurea coating and a preparation method thereof, and relates to the technical field of polyurea coatings. The MOFs-based antistatic agent is prepared from the following components in parts by mass: 0.2 to 1 part of a single-walled carbon nanotube, 1.5 to 4 parts of an antistatic agent and 0.05 to 0.3 part of an MOFs material, metal salt related to the MOFs material is acetylacetone metal salt, and a ligand is 2-methylimidazole; the antistatic agent is at least one of a polyether type antistatic agent, a polyacrylate type antistatic agent, a sulfonic acid derivative type antistatic agent and a polyquaternium type antistatic agent. The MOFs-based antistatic agent provided by the invention is applied to the polyurea coating, so that the antistatic property of the polyurea coating is improved, the viscosity of the polyurea coating is reduced, and the coating strength of the polyurea coating is relatively high.

Description

Technical Field

[0001] The invention relates to the technical field of polyurea coatings, and in particular to a MOFs-based antistatic agent, a polyurea coating and a preparation method thereof. Background Art

[0002] Polyurea coating is a new type of solvent-free, pollution-free, two-component, fast-curing green coating, mainly composed of polyaspartic acid ester resin and isocyanate. The secondary amine group (-NH-) on the polyaspartic acid ester resin reacts with the -NCO group in the isocyanate to form a urea bond (-NHCONH-), which is quickly cross-linked and cured into a three-dimensional network structure. Polyurea coating exhibits excellent chemical stability and has the characteristics of good flexibility, high strength, corrosion resistance, and aging resistance.

[0003] While retaining the original excellent performance of polyurea coatings, antistatic polyurea coatings significantly reduce the surface resistivity of the coatings by introducing antistatic agents or conductive fillers, allowing the charge to be released quickly, effectively avoiding surface charge accumulation, and thus achieving the antistatic function of the coatings. Antistatic coatings have been widely used in many important fields such as the aerospace industry, petrochemical industry, electronic manufacturing, high-end equipment manufacturing, and plastic packaging industry.

[0004] However, the amount of conductive fillers or antistatic agents used in most antistatic coatings is too high (generally more than 5%). On the one hand, too much conductive filler and antistatic agent will easily cause "agglomeration" in the polymer matrix, which will have an adverse effect on the mechanical and optical properties of the material. On the other hand, adding a large amount of conductive fillers and antistatic agents will significantly increase the viscosity of the resin. During the construction process, higher temperature and pressure are required to achieve the ideal spraying fluidity and molding effect, which increases the construction difficulty and cost.

[0005] CN118978848A discloses an antistatic water-based polyurea coating and a preparation method thereof, wherein carbon nanotubes are modified by a PVP dispersant so that the carbon nanotubes can be uniformly dispersed in the water-based polyurea coating to obtain an antistatic polyurea coating. The patent improves the compatibility of carbon nanotubes and polyurea coating by using a polyvinyl pyrrolidone dispersant containing hydrophilic carboxyl and amino groups to enhance the interface between carbon nanotubes and polyurea. However, the preparation process is cumbersome, the reaction conditions are strict, and the yield is low, so it is not suitable for mass production.

[0006] In summary, it is still a technical challenge to reasonably control the amount of conductive fillers and antistatic agents added in antistatic polyurea coatings to ensure the formation of a uniform and stable conductive network while maintaining strong conductive stability.

[0007] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0008] In view of this, the present invention proposes a MOFs-based antistatic agent, a polyurea coating and a preparation method thereof.

[0009] The technical solution of the present invention is implemented as follows: The present invention provides a MOFs-based antistatic agent, which comprises, by weight, 0.2 to 1 parts of single-walled carbon nanotubes, 1.5 to 4 parts of antistatic agents, and 0.05 to 0.3 parts of MOF materials, wherein the metal salt involved in the MOFs material is acetylacetone metal salt, and the ligand is 2-methylimidazole;

[0010] The antistatic agent is at least one of a polyether antistatic agent, a polyacrylate antistatic agent, a sulfonic acid derivative antistatic agent, and a polyquaternary ammonium salt antistatic agent.

[0011] The present invention also provides a MOFs-based antistatic polyurea coating, comprising a component A and a component B, wherein the mass ratio of the component A to the component B is (2-3):1;

[0012] The component A comprises: by weight, 40 to 60 parts of polyaspartic acid ester resin, 0.4 to 1.2 parts of dispersant, 14 to 25 parts of titanium dioxide, 0.4 to 1.4 parts of defoamer, 0.4 to 0.8 parts of leveling agent, and 1.75 to 5.3 parts of MOFs-based antistatic agent;

[0013] The B component includes an isocyanate curing agent, and the viscosity of the isocyanate curing agent is 30 to 100 mPa·s.

[0014] The present invention also provides a method for preparing the above-mentioned MOFs-based antistatic polyurea coating, comprising the following steps:

[0015] S100, mixing polyaspartic acid ester resin, dispersant, titanium dioxide, defoamer, and leveling agent, and stirring and dispersing at 1000 rpm to 2000 rpm / min for 5 min to 10 min to obtain a first mixture;

[0016] S200, adding single-walled carbon nanotubes and antistatic agent to the first mixture, stirring and dispersing at 3800rpm-4600rpm / min for 15min-25min; then adding MOFs material thereto, stirring and dispersing at 3800rpm-4600rpm / min for 10min-15min; finally stirring and dispersing at 200rpm-400rpm / min for 5min-10min to obtain component A;

[0017] S300, mixing component A with component B, stirring and dispersing them at 3800 rpm to 4600 rpm / min for 10 min to 15 min, to obtain a MOFs-based antistatic polyurea coating.

[0018] On the basis of the above technical solution, preferably, the preparation process of the MOF material comprises the following steps:

[0019] S1, mixing the metal salt and the organic ligand in a molar ratio of 1:(2-3), stirring and passing through a 50-100 mesh sieve to obtain a precursor powder;

[0020] S2, evenly spreading the precursor powder obtained in step S1 in a porcelain boat, and then placing the porcelain boat in a tube furnace for heating treatment to obtain MOFs raw materials;

[0021] S3. After ball milling the MOFs raw material for 1 to 3 hours, the raw material is sieved through a 100-200 mesh sieve to obtain the MOFs material.

[0022] Based on the above technical solution, preferably, in step S2, the heating treatment includes:

[0023] A protective atmosphere is introduced into the tubular furnace at a gas flow rate of 150 to 300 cc / min. At the same time, the tubular furnace is heated to 100 to 120°C at a heating rate of 2 to 4°C / min, and the gas inlet valve is closed;

[0024] The tube furnace is evacuated to a vacuum state, and then the temperature is raised to 200-225°C at a heating rate of 2-3°C / min, and kept at this temperature for 3-5 hours;

[0025] After the heat preservation under vacuum is completed, the furnace is cooled to room temperature to obtain the MOFs raw material. Based on the above technical solution, preferably, in step S3, during ball milling, the rotation speed is 150rpm / min to 250rpm / min, the mass ratio of the raw material to the ball milling beads is 0.15 to 0.25; and the diameter of the ball milling beads is 0.3 to 10 mm.

[0026] On the basis of the above technical solution, preferably, the length of the single-walled carbon nanotube is 5 to 20 μm, and the diameter of the single-walled carbon nanotube along a cross section perpendicular to the length direction is 1 to 1.8 nm.

[0027] On the basis of the above technical solution, preferably, the isocyanate curing agent is 4,4'-dicyclohexylmethane diisocyanate.

[0028] On the basis of the above technical solution, preferably, the acetylacetonate metal salt is zinc acetylacetonate or cobalt acetylacetonate.

[0029] On the basis of the above technical solution, preferably, the dispersant is a polyacrylic acid dispersant;

[0030] The polyacrylic acid dispersant is at least one of polymethyl acrylate, polybutyl acrylate, polyethyl acrylate and cross-linked polyacrylic acid.

[0031] More preferably, the leveling agent is polyether-modified siloxane.

[0032] The MOFs-based antistatic agent, polyurea coating and preparation method thereof of the present invention have the following beneficial effects compared with the prior art:

[0033] 1. The novel MOFs-based antistatic agent proposed in the present invention is composed of several micro-nano antistatic fillers of different morphologies, including single-walled carbon nanotubes, polymer permanent liquid antistatic agents and MOFs materials. Nano-scale MOFs materials have hydrophilic groups and can be adsorbed on single-walled carbon nanotubes, which improves the compatibility of carbon nanotubes with resins, makes the novel antistatic agent have good dispersibility in the resin, and reduces the viscosity of the coating; at the same time, nano-scale MOFs materials can be filled in the conductive network constructed by fibrous one-dimensional nanomaterial single-walled carbon nanotubes and polymer permanent liquid antistatic agents, and synergize with single-walled carbon nanotubes with excellent conductivity and polymer permanent liquid antistatic agents to improve the antistatic performance of the novel antistatic agent.

[0034] 2. The present invention adopts a method of mixing and adding a new MOFs-based antistatic agent in stages when preparing MOFs-based antistatic polyurea coatings. First, single-walled carbon nanotubes with longer sizes and polymer permanent liquid antistatic agents are added to polyaspartic acid resins, and the two are evenly dispersed in the polyaspartic acid resin to construct a basic conductive network; secondly, nano-scale MOF materials are added, and the MOF materials can be adsorbed on the single-walled carbon nanotubes and filled in the conductive network and polyaspartic acid resin materials that have been built, and the remaining dispersed single-walled carbon nanotubes and antistatic agents are connected to ensure that all fillers can be evenly dispersed in the polyaspartic acid resin material, and finally form an interconnected 3D continuous and uniform conductive network, so that the polyurea coating has a better antistatic effect. At the same time, the antistatic performance of the coating formed by the polyurea coating can be improved when the amount of MOFs-based antistatic agent added is small, the viscosity of the coating can be reduced, and the production cost and construction cost of the polyurea coating can be reduced.

[0035] 3. The MOFs material used in the present invention is prepared by an all-solid-phase synthesis process originally developed by the Functional Hybrid Materials Laboratory of Wuhan University of Technology, and has the advantages of short synthesis cycle, high yield, mass production, and being green and pollution-free.

[0036] 4. The MOFs-based antistatic polyurea coating of the present invention is a solvent-free, two-component green coating with a simple preparation method and low cost, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 Schematic diagram of the conductive network in MOFs-based polyurea coating in some embodiments of the present disclosure.

[0039] Figure 2 The present invention is a flow chart for preparing MOFs-based antistatic polyurea coatings in some embodiments of the present invention.

[0040] Figure 3 This is a schematic diagram of a MOFs-based antistatic polyurea coating in one embodiment of the present disclosure.

[0041] Figure 4 This is a schematic diagram of a coating formed by a MOFs-based antistatic polyurea coating in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0042] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] An embodiment of the present disclosure provides a MOFs-based antistatic agent, which includes, by mass, 0.2 to 1 parts of single-walled carbon nanotubes, 1.5 to 4 parts of antistatic agents, and 0.05 to 0.3 parts of MOFs materials. The MOFs material is ZIF-8 or ZIF-67, the metal salt involved is acetylacetonate metal salt, and the ligand is 2-methylimidazole.

[0044] In this embodiment, by adding MOFs material to the polyurea coating, more contact points are provided for the conductive filler (single-walled carbon nanotubes) and the antistatic agent, which promotes the uniform dispersion of the single-walled carbon nanotubes and the antistatic agent, and is conducive to forming a uniform and continuous conductive network in the polyurea coating, thereby achieving the stability of the conductive network. Figure 1The red line with an arrow shows a conductive path formed by single-walled carbon nanotubes, antistatic agents and MOFs materials in polyurea coatings. At the same time, the porous structure of MOFs materials can absorb moisture and gas in the environment, reduce the concentration of charges on the coating surface, and play a role in charge shielding and dispersion.

[0045] In some embodiments of the present disclosure, the antistatic agent may be a polymer permanent liquid antistatic agent. The polymer permanent liquid antistatic agent has a long-lasting antistatic effect and can form a three-dimensional ion conductive network structure in the matrix of the polyurea coating, thereby reducing the volume resistivity of the polyurea coating matrix itself and being less affected by environmental humidity.

[0046] In some examples, the antistatic agent may be at least one of a polyether antistatic agent, a polyacrylate antistatic agent, a sulfonic acid derivative antistatic agent, and a polyquaternary ammonium salt antistatic agent.

[0047] Exemplarily, the polyether antistatic agent may be polyether-L44 produced by Hai'an (Linyi) Guoli Chemical Co., Ltd., the main component of which is propylene glycol block polyether.

[0048] Exemplarily, the polyacrylate antistatic agent may be JL-WT1 type or JL-WT1 type produced by Shandong Juli Antistatic Technology Co., Ltd., the main component of which is polyallylamine hydrochloride.

[0049] For example, the sulfonic acid derivative antistatic agent may be sodium dodecylbenzene sulfonate produced by Jinan Shengming Chemical Co., Ltd.

[0050] Exemplarily, the polyquaternary ammonium salt antistatic agent may be antistatic agent SN produced by Hubei Kewode Chemical Co., Ltd. or KJ-208 produced by Quanzhou Fengze District Kejun Chemical Co., Ltd., the main component of which is octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate.

[0051] The embodiment of the present disclosure also provides a MOFs-based antistatic polyurea coating, including component A and component B, the mass ratio of component A to component B is (2-3):1; the component A includes: by mass, 40-60 parts of polyaspartic acid ester resin, 0.4-1.2 parts of dispersant, 14-25 parts of titanium dioxide, 0.4-1.4 parts of defoaming agent, 0.4-0.8 parts of leveling agent, the MOFs-based antistatic agent includes: 0.2-1 parts of single-walled carbon nanotubes, 1.5-4 parts of antistatic agent, and 0.05-0.3 parts of MOFs material; the component B includes an isocyanate curing agent, and the viscosity of the isocyanate curing agent is 30-100 mPa·s.

[0052] In this embodiment, due to the addition of MOFs materials, the formation of a conductive network in the polyurea coating is increased, and a higher antistatic property of the polyurea coating can be achieved under the premise of a lower amount of antistatic filler (single-walled carbon nanotubes, antistatic agent and MOFs materials). Avoid adding too much antistatic filler, which will cause agglomeration in the polyaspartic acid resin matrix, and have an adverse effect on the mechanical and optical properties of the polyurea coating. At the same time, avoid adding too much antistatic filler, which will increase the viscosity of the polyaspartic acid resin. During use, higher temperature and pressure conditions are required to achieve ideal spray fluidity and molding effects, which increases the difficulty and cost of construction.

[0053] In one embodiment of the present disclosure, the polyaspartic acid resin is at least one of polyaspartic acid resin F420, polyaspartic acid resin F520 and polyaspartic acid resin F220 prepared by Shenzhen Feiyang Junyan New Materials Co., Ltd.

[0054] In one embodiment of the present disclosure, the length of the single-walled carbon nanotube is 5 to 20 μm, and the diameter of the single-walled carbon nanotube along the cross section perpendicular to the length direction is 1 to 1.8 nm. The single-walled carbon nanotube can form a good conductive network in the matrix of the polyurea coating and has good conductive properties. For example, the length of the single-walled carbon nanotube can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm or 20 μm; the diameter of the single-walled carbon nanotube along the cross section perpendicular to the length direction can be 1 nm, 1.3 nm, 1.5 nm, 1.7 nm or 1.8 nm.

[0055] For example, the average length of the single-walled carbon nanotube is 8 μm, and the average diameter of the single-walled carbon nanotube along the cross section perpendicular to the length direction is 1.7 nm. For example, the single-walled carbon nanotube can be produced by Okoshiel Trading (Shenzhen) Co., Ltd.

[0056] In one example, the isocyanate curing agent is 4,4'-dicyclohexylmethane diisocyanate.

[0057] In one embodiment of the present disclosure, the dispersant may be a polyacrylic acid dispersant. The polyacrylic acid dispersant can form a protective layer on the polymer chains in component A, thereby reducing the aggregation tendency of the polymer. In some examples, the polyacrylic acid dispersant may be at least one of polymethyl acrylate (PMA), polybutyl acrylate (PBA), polyethyl acrylate (PAEb), or cross-linked polyacrylic acid (gPAA).

[0058] In one embodiment of the present disclosure, the leveling agent may be a polyether-modified siloxane. The polyether-modified siloxane may reduce the surface tension of the prepared polyurea coating, prevent shrinkage cavities, improve the surface flow state of the polyurea coating, and improve the smoothness and gloss of the formed coating surface. The polyether-modified siloxane may be at least one of BYK-302, BYK-331, BYK-333, and BYK-335 of BYK.

[0059] In one embodiment of the present disclosure, the defoaming agent may be at least one of BYK-A535, BYK-A500, BYK-A501, BYK-A550, and BYK-A555 produced by BYK.

[0060] In one embodiment of the present disclosure, the preparation process of the MOFs material comprises the following steps:

[0061] S1, mixing the metal salt and the organic ligand in a molar ratio of 1:(2-3), stirring and passing through a 50-100 mesh sieve to obtain a precursor powder;

[0062] S2, evenly spreading the precursor powder obtained in step S1 in a porcelain boat, and then placing the porcelain boat in a tube furnace for heating treatment to obtain MOFs raw materials;

[0063] S3. After ball milling the MOFs raw material for 1 to 3 hours, the ball mill passes through a 100-200 mesh sieve to obtain the MOFs material.

[0064] The present embodiment adopts the full solid phase synthesis process to prepare MOFs material, and the preparation is solvent-free throughout, short time consumption, high yield, and pollution-free. The prepared MOFs material is added to the conductive network of polyaspartic acid resin, which can provide more contact points for single-walled carbon nanotubes and antistatic agents, and build a more continuous, uniform and stable conductive network. It is also possible to make the MOFs material adsorbed on single-walled carbon nanotubes and filled in polyaspartic acid resin based on the hydrophilicity of MOFs material, improve the compatibility of single-walled carbon nanotubes with polyaspartic acid resin and the dispersibility of single-walled carbon nanotubes in polyaspartic acid resin, prevent single-walled carbon nanotubes and antistatic agents from agglomerating in polyaspartic acid resin, thereby reducing the viscosity of the coating and improving antistatic properties.

[0065] In a specific embodiment, the metal salt of acetylacetonate is one of zinc acetylacetonate and cobalt acetylacetonate. Zinc acetylacetonate and 2-methylimidazole can be used to synthesize ZIF-8; cobalt acetylacetonate and 2-methylimidazole can be used to synthesize ZIF-67.

[0066] In one embodiment of the present disclosure, in step S2, the heating treatment includes: introducing a protective atmosphere into the tubular furnace, with a gas flow rate of 150 to 300 cc / min, while the tubular furnace is heated to 100 to 120°C at a heating rate of 2 to 4°C / min, and the air inlet valve is closed; the tubular furnace is evacuated to a vacuum state, and then heated to 200 to 225°C at a heating rate of 2 to 3°C / min, and kept warm for 3 to 5 hours; after the insulation under vacuum is completed, the furnace is cooled to room temperature to obtain MOFs raw materials.

[0067] For example, before the tube furnace is evacuated, the gas flow rate is 150cc / min, 170cc / min, 190cc / min, 220cc / min, 240cc / min, 260cc / min, 280cc / min or 300cc / min; the heating rate of the tube furnace can be 2℃ / min, 2.5℃ / min, 3℃ / min, 3.5℃ / min or 4℃ / min. It should be noted that heating to 100-120℃ means heating to within the temperature range. For example, heating to 98℃ or 122℃ is achievable in the process. In the actual process, the temperature can fluctuate within a certain range, and the fluctuation can be understood as meeting the above temperature limit.

[0068] For example, the heating rate of the tubular furnace before vacuuming the tubular furnace can be 2°C / min, 2.2°C / min, 2.4°C / min, 2.6°C / min, 2.8°C / min or 3°C / min; the insulation time after heating can be 3h, 3.5h, 4h, 4.5h or 5h.

[0069] In one embodiment of the present disclosure, in step S3, during ball milling, the rotation speed is 150rpm / min to 250rpm / min, the mass ratio of MOFs raw materials to ball milling beads is 0.15 to 0.25; the diameter of the ball milling beads is 0.3 to 10mm. Too many ball milling beads may cause excessive grinding of MOFs raw materials and increase energy consumption; conversely, if there are too many MOFs raw materials, it may lead to insufficient grinding. If the diameter of the ball milling beads is too large, the impact force on the MOFs raw materials is large, and the MOFs raw materials can be easily crushed, but it is difficult to grind them finely, and there are easy to be grinding dead corners; if the diameter of the ball milling beads is too small, the number of collisions is large, which has a great effect on the grinding of fine MOFs raw materials, but its impact force is small, and it is difficult to grind larger MOFs raw materials.

[0070] The present disclosure also provides a method for preparing the above-mentioned MOFs-based antistatic polyurea coating, such as Figure 2 As shown, the method comprises the following steps:

[0071] S100, mixing polyaspartic acid ester resin, dispersant, titanium dioxide, defoamer, and leveling agent, and stirring and dispersing at 1000 rpm to 2000 rpm / min for 5 min to 10 min to obtain a first mixture;

[0072] S200, adding single-walled carbon nanotubes and antistatic agent to the first mixture, stirring and dispersing at 3800rpm-4600rpm / min for 15min-25min; then adding MOFs material thereto, stirring and dispersing at 3800rpm-4600rpm / min for 10min-15min; finally stirring and dispersing at 200rpm-400rpm / min for 5min-10min to obtain component A;

[0073] S300, mixing component A with component B containing an isocyanate curing agent in a mass ratio of (2-3):1, stirring and dispersing at 3800 rpm-4600 rpm / min for 10 min-15 min, to obtain a MOFs-based antistatic polyurea coating.

[0074] When preparing polyurea coatings, single-walled carbon nanotubes with excellent conductive properties, polymer liquid antistatic agents and MOFs materials with special structures are evenly dispersed in the curing system of polyaspartic acid ester resin through high-speed dispersion, and MOFs materials with high specific surface area and porous structure act as a bridge to connect the basic conductive network built by fibrous one-dimensional nanomaterial single-walled carbon nanotubes and low-molecular chain polymer liquid antistatic agents. This ensures that all antistatic fillers are evenly dispersed in the polyaspartic acid ester resin and can form a complete and continuous three-dimensional conductive network, thereby improving the comprehensive performance of the material. At the same time, it can improve the antistatic performance of the coating with less filler addition, reduce the viscosity of the coating, and reduce the production cost and construction cost of the coating.

[0075] In one embodiment of the present disclosure, in step S100, the stirring and dispersing is performed using a disperser, and the disperser includes a dispersion tank with a cooling system; after the polyaspartic acid ester resin, dispersant, titanium dioxide, defoaming agent, and leveling agent are mixed, the mixture is stirred and dispersed at 15 to 25° C.; and the influence of heat generated during high-speed stirring on the polyaspartic acid ester resin with additives is avoided.

[0076] The MOFs-based antistatic polyurea coating provided by the present disclosure is further described below in conjunction with specific examples.

[0077] Example 1

[0078] (1) Preparation of MOFs materials

[0079] S1. Place zinc acetylacetonate and 2-methylimidazole in a three-necked flask at a molar ratio of 1:3, stir and mix manually for 5 minutes to obtain a fine powder with uniform color and no obvious particles, and pass through a 50-mesh sieve to obtain a precursor powder.

[0080] S2. Evenly spread the precursor powder obtained in step S1 in a porcelain boat, and then place the porcelain boat in a tube furnace for pyrolysis treatment to obtain MOFs raw materials. The heating treatment includes: (1) introducing a protective atmosphere into the tube furnace, with a gas flow rate of 200cc / min, and the protective atmosphere is argon; at the same time, the tube furnace is heated to 100°C at a heating rate of 3°C / min, and the air inlet valve is closed; (2) the tube furnace is evacuated to a vacuum state, and then heated to 200°C at a heating rate of 2.5°C / min, and kept warm for 4 hours; (3) after the vacuum insulation is completed, the furnace is cooled to room temperature to obtain MOFs raw materials.

[0081] S3. The MOFs raw material was ball-milled at a speed of 200 rpm / min (the mass ratio of the raw material to the ball milling beads was 0.2; the diameter of the ball milling beads was 5 mm) for 2 h, and then passed through a 200-mesh sieve to obtain the MOFs material.

[0082] (2) Preparation of MOFs-based antistatic polyurea coatings

[0083] S100, 40 parts of polyaspartic acid resin F420 (Shenzhen Feiyang Junyan New Materials Co., Ltd.), 1 part of dispersant polymethyl acrylate (PMA), 20 parts of titanium dioxide, 1 part of defoamer BYK-A535 (Bick, Germany), 0.5 part of leveling agent BYK-302 (Bick, Germany) are added to the dispersion tank of the high-speed disperser in sequence, and the high-speed disperser is stirred and dispersed for 10 minutes under the condition that the speed of the high-speed disperser is 2000rpm / min, so that the additives are evenly dispersed in the polyaspartic acid resin to obtain a first mixture. Wherein, the dispersion tank of the high-speed disperser has a cooling system, so that the temperature in the dispersion tank is 15-25°C during the stirring and dispersing process.

[0084] S200. Add 0.3 parts of single-walled carbon nanotubes (the average length of the single-walled carbon nanotubes is 8 μm, and the average diameter of the cross section perpendicular to the length is 1 nm) and 1.8 parts of antistatic agent polyether-L44 (Haian (Linyi) Guoli Chemical Co., Ltd.) to the first mixture, adjust the speed of the high-speed disperser to 4000 rpm / min, stir and disperse for 25 minutes, then add 0.06 parts of MOFs material (prepared in this embodiment), adjust the speed of the high-speed disperser to 4000 rpm / min, stir and disperse for 15 minutes; then adjust the speed of the high-speed disperser to 200 rpm / min, stir and disperse for 5 minutes to defoam, and obtain component A.

[0085] S300, adding component A and component B (curing agent: 4,4'-dicyclohexylmethane diisocyanate) into a dispersion tank of a high-speed disperser in batches according to a mass ratio of 2:1, stirring and dispersing at 4000 rpm / min for 10 minutes, and obtaining a MOFs-based antistatic polyurea coating defined as polyurea coating 1, such as Figure 3 shown.

[0086] Example 2

[0087] The difference from Example 1 is that when preparing the MOFs material, the molar ratio of zinc acetylacetonate to 2-methylimidazole is 1:2. The prepared MOFs-based antistatic polyurea coating is defined as polyurea coating 2.

[0088] Example 3

[0089] The difference from Example 1 is that when preparing the MOFs material, the molar ratio of zinc acetylacetonate to 2-methylimidazole is 1:2.5. The prepared MOFs-based antistatic polyurea coating is defined as polyurea coating 3.

[0090] Example 4

[0091] (1) Preparation of MOFs materials

[0092] S1. Place zinc acetylacetonate and 2-methylimidazole in a three-necked flask at a molar ratio of 1:2.2, stir and mix manually for 5 minutes to achieve a fine powder state with uniform color and no obvious particles, and pass through a 100-mesh sieve to obtain a precursor powder.

[0093] S2. Evenly spread the precursor powder obtained in step S1 in a porcelain boat, and then place the porcelain boat in a tube furnace for pyrolysis treatment to obtain MOFs raw materials. The heating treatment includes: (1) introducing a protective atmosphere into the tube furnace, with a gas flow rate of 150cc / min, and the protective atmosphere is argon; at the same time, the tube furnace is heated to 120°C at a heating rate of 4°C / min, and the air inlet valve is closed; (2) the tube furnace is evacuated to a vacuum state, and then heated to 225°C at a heating rate of 2°C / min, and kept warm for 3 hours; (3) after the vacuum insulation is completed, the furnace is cooled to room temperature to obtain MOFs raw materials.

[0094] S3. The MOFs raw material was ball-milled at a speed of 150 rpm / min (the mass ratio of the raw material to the ball milling beads was 0.25; the diameter of the ball milling beads was 0.3 mm) for 1 h, and then passed through a 100-mesh sieve to obtain the MOFs material.

[0095] (2) Preparation of MOFs-based antistatic polyurea coatings

[0096] S100, 54 parts of polyaspartic acid resin F520 (Shenzhen Feiyang Junyan New Materials Co., Ltd.), 1 part of dispersant polybutyl acrylate (PBA), 18 parts of titanium dioxide, 1.4 parts of defoamer BYK-A501 (Bick, Germany), 0.6 parts of leveling agent BYK-333 (Bick, Germany) are added to the dispersion tank of the high-speed disperser in sequence, and the high-speed disperser is stirred and dispersed for 10 minutes under the condition that the speed of the high-speed disperser is 2000rpm / min, so that the additives are evenly dispersed in the polyaspartic acid resin to obtain a first mixture. Wherein, the dispersion tank of the high-speed disperser has a cooling system, so that the temperature in the dispersion tank is 15-25°C during the stirring and dispersing process.

[0097] S200. Add 0.3 parts of single-walled carbon nanotubes (the average length of the single-walled carbon nanotubes is 10 μm, and the average diameter of the section perpendicular to the length is 1.6 nm) and 3.7 parts of antistatic agent SN (Hubei Kewode Chemical Co., Ltd.) to the first mixture, adjust the speed of the high-speed disperser to 4000 rpm / min, stir and disperse for 25 minutes, add 0.24 parts of MOFs material (prepared in this embodiment), adjust the speed of the high-speed disperser to 4000 rpm / min, stir and disperse for 15 minutes; then adjust the speed of the high-speed disperser to 200 rpm / min, stir and disperse for 5 minutes to defoam, and obtain component A.

[0098] S300. Add component A and component B (curing agent: 4,4'-dicyclohexylmethane diisocyanate) into the dispersion tank of a high-speed disperser in batches at a mass ratio of 2.7:1, and stir and disperse for 10 minutes at 4000 rpm / min to obtain a MOFs-based antistatic polyurea coating defined as polyurea coating 4.

[0099] Example 5

[0100] (1) Preparation of MOFs materials

[0101] S1. Place cobalt acetylacetonate and 2-methylimidazole in a three-necked flask at a molar ratio of 1:2.8, stir and mix manually for 5 minutes to achieve a fine powder state with uniform color and no obvious particles, and pass through an 80-mesh sieve to obtain a precursor powder.

[0102] S2. Evenly spread the precursor powder obtained in step S1 in a porcelain boat, and then place the porcelain boat in a tube furnace for pyrolysis treatment to obtain MOFs raw materials. The heating treatment includes: (1) introducing a protective atmosphere into the tube furnace, with a gas flow rate of 150cc / min, and the protective atmosphere is argon; at the same time, the tube furnace is heated to 120°C at a heating rate of 3.5°C / min, and the air inlet valve is closed; (2) the tube furnace is evacuated to a vacuum state, and then heated to 210°C at a heating rate of 2.2°C / min, and kept warm for 4 hours; (3) after the vacuum insulation is completed, the furnace is cooled to room temperature to obtain MOFs raw materials.

[0103] S3. The MOFs raw material was ball-milled at a speed of 250 rpm / min (the mass ratio of the raw material to the ball milling beads was 0.15; the diameter of the ball milling beads was 10 mm) for 3 h, and then passed through a 120-mesh sieve to obtain the MOFs material.

[0104] (2) Preparation of MOFs-based antistatic polyurea coatings

[0105] S100, add 60 parts of polyaspartic acid resin F220 (Shenzhen Feiyang Junyan New Materials Co., Ltd.), 1.2 parts of dispersant polyethyl acrylate, 25 parts of titanium dioxide, 1.4 parts of defoamer BYK-A555 (Bick, Germany), and 0.8 parts of leveling agent BYK-335 (Bick, Germany) to the dispersion tank of the high-speed disperser in sequence, and stir and disperse for 8 minutes under the condition that the high-speed disperser speed is 1500rpm / min, so that the additives are evenly dispersed in the polyaspartic acid resin to obtain the first mixture. Wherein, the dispersion tank of the high-speed disperser has a cooling system, so that the temperature in the dispersion tank is 15-25°C during the stirring and dispersing process.

[0106] S200. Add 1 part of single-walled carbon nanotubes (the average length of the single-walled carbon nanotubes is 5 μm, and the average diameter of the section perpendicular to the length is 1.8 nm) and 4 parts of antistatic agent SN (Hubei Kewode Chemical Co., Ltd.) to the first mixture, adjust the speed of the high-speed disperser to 4600 rpm / min, stir and disperse for 20 minutes, then add 0.3 parts of MOFs material (prepared in this embodiment), adjust the speed of the high-speed disperser to 4600 rpm / min, stir and disperse for 10 minutes; then adjust the speed of the high-speed disperser to 300 rpm / min, stir and disperse for 10 minutes to defoam, and obtain component A.

[0107] S300, adding component A and component B (curing agent: 4,4'-dicyclohexylmethane diisocyanate) into a dispersion tank of a high-speed disperser in batches according to a mass ratio of 3:1, stirring and dispersing at 4000 rpm / min for 10 minutes, and obtaining a MOFs-based antistatic polyurea coating defined as polyurea coating 5.

[0108] Example 6

[0109] (1) Preparation of MOFs materials

[0110] S1. Place zinc acetylacetonate and 2-methylimidazole in a three-necked flask at a molar ratio of 1:2, stir and mix manually for 5 minutes to obtain a fine powder with uniform color and no obvious particles, and pass through a 60-mesh sieve to obtain a precursor powder.

[0111] S2. Evenly spread the precursor powder obtained in step S1 in a porcelain boat, and then place the porcelain boat in a tube furnace for pyrolysis treatment to obtain MOFs raw materials. The heating treatment includes: (1) introducing a protective atmosphere into the tube furnace, with a gas flow rate of 300cc / min, and the protective atmosphere is argon; at the same time, the tube furnace is heated to 110°C at a heating rate of 2°C / min, and the air inlet valve is closed; (2) the tube furnace is evacuated to a vacuum state, and then heated to 200°C at a heating rate of 3°C / min, and kept warm for 3.5 hours; (3) after the vacuum insulation is completed, the furnace is cooled to room temperature to obtain MOFs raw materials.

[0112] S3. The MOFs raw material was ball-milled at a speed of 180 rpm / min (the mass ratio of the raw material to the ball milling beads was 0.21; the diameter of the ball milling beads was 8 mm) for 2 h, and then passed through a 160-mesh sieve to obtain the MOFs material.

[0113] (2) Preparation of MOFs-based antistatic polyurea coating 6

[0114] S100, 40 parts of polyaspartic acid resin F420 (Shenzhen Feiyang Junyan New Materials Co., Ltd.), 1 part of dispersant polymethyl acrylate (PMA), 20 parts of titanium dioxide, 0.4 parts of defoamer BYK-A535 (Bick, Germany), 0.4 parts of leveling agent BYK-302 (Bick, Germany) are added to the dispersion tank of the high-speed disperser in sequence, and the high-speed disperser is stirred and dispersed for 5 minutes under the condition that the speed of the high-speed disperser is 1000rpm / min, so that the additives are evenly dispersed in the polyaspartic acid resin to obtain a first mixture. Wherein, the dispersion tank of the high-speed disperser has a cooling system, so that the temperature in the dispersion tank is 15-25°C during the stirring and dispersing process.

[0115] S200. Add 0.2 parts of single-walled carbon nanotubes (the average length of the single-walled carbon nanotubes is 10 μm, and the average diameter of the section perpendicular to the length is 1.5 nm) and 1.5 parts of antistatic agent polyether-L44 (Haian (Linyi) Guoli Chemical Co., Ltd.) to the first mixture, adjust the speed of the high-speed disperser to 3800 rpm / min, stir and disperse for 15 minutes, then add 0.05 parts of MOFs material (prepared in this embodiment), adjust the speed of the high-speed disperser to 3800 rpm / min, stir and disperse for 10 minutes; then adjust the speed of the high-speed disperser to 400 rpm / min, stir and disperse for 8 minutes to defoam, and obtain component A.

[0116] S300. Add component A and component B (curing agent: 4,4'-dicyclohexylmethane diisocyanate) into a dispersion tank of a high-speed disperser in batches at a mass ratio of 2.5:1, and stir and disperse for 10 minutes at 4000 rpm / min to obtain a MOFs-based antistatic polyurea coating defined as polyurea coating 6.

[0117] Example 7

[0118] S1. Place zinc acetylacetonate and 2-methylimidazole in a three-necked flask at a molar ratio of 1:2.6, stir and mix manually for 5 minutes to obtain a fine powder with uniform color and no obvious particles, and pass through a 70-mesh sieve to obtain a precursor powder.

[0119] S2. Evenly spread the precursor powder obtained in step S1 in a porcelain boat, and then place the porcelain boat in a tube furnace for pyrolysis treatment to obtain MOFs raw materials. The heating treatment includes: (1) introducing a protective atmosphere into the tube furnace, with a gas flow rate of 250cc / min, and the protective atmosphere is argon; at the same time, the tube furnace is heated to 100°C at a heating rate of 2.5°C / min, and the air inlet valve is closed; (2) the tube furnace is evacuated to a vacuum state, and then heated to 220°C at a heating rate of 2.8°C / min, and kept warm for 5 hours; (3) after the vacuum insulation is completed, the furnace is cooled to room temperature to obtain MOFs raw materials.

[0120] S3. The MOFs raw material was ball-milled at a speed of 220 rpm / min (the mass ratio of the raw material to the ball milling beads was 0.18; the diameter of the ball milling beads was 1 mm) for 3 h, and then passed through a 200-mesh sieve to obtain the MOFs material.

[0121] (2) Preparation of MOFs-based antistatic polyurea coatings

[0122] S100, 54 parts of polyaspartic acid resin F520 (Shenzhen Feiyang Junyan New Materials Co., Ltd.), 0.4 parts of dispersant polybutyl acrylate (PBA), 14 parts of titanium dioxide, 1.4 parts of defoamer BYK-A501 (Bick, Germany), 0.6 parts of leveling agent BYK-333 (Bick, Germany) are added to the dispersion tank of the high-speed disperser in sequence, and the high-speed disperser is stirred and dispersed for 10 minutes under the condition that the speed of the high-speed disperser is 2000rpm / min, so that the additives are evenly dispersed in the polyaspartic acid resin to obtain a first mixture. Wherein, the dispersion tank of the high-speed disperser has a cooling system, so that the temperature in the dispersion tank is 15-25°C during the stirring and dispersing process.

[0123] S200. Add 0.8 parts of single-walled carbon nanotubes (the average length of the single-walled carbon nanotubes is 20 μm, and the average diameter of the section perpendicular to the length is 1.6 nm) and 2.5 parts of antistatic agent SN (Hubei Kewode Chemical Co., Ltd.) to the first mixture, adjust the speed of the high-speed disperser to 4000 rpm / min, stir and disperse for 25 minutes, then add 0.24 parts of MOFs material (prepared in this embodiment), adjust the speed of the high-speed disperser to 4000 rpm / min, stir and disperse for 15 minutes; then adjust the speed of the high-speed disperser to 200 rpm / min, stir and disperse for 5 minutes to defoam, and obtain component A.

[0124] S300, adding component A and component B (curing agent: 4,4'-dicyclohexylmethane diisocyanate) in batches according to a mass ratio of 2.7:1 into a dispersion tank of a high-speed disperser, stirring and dispersing at 4000 rpm / min for 10 minutes, and obtaining a MOFs-based antistatic polyurea coating defined as polyurea coating 4. Comparative Example 1

[0125] The difference between Comparative Example 1 and Example 1 is that in step S200, 2.16 parts of carbon black are added to the first mixture and then stirred and dispersed. The remaining operations and component parameters are the same as those of Example 1, and the prepared polyurea coating is defined as polyurea coating C1.

[0126] Comparative Example 2

[0127] The difference between Comparative Example 2 and Example 1 is that in step S200, 2.16 parts of reduced graphene oxide (particle size 10 μm) are added to the first mixture and then stirred and dispersed. The remaining operations and component parameters are the same as those of Example 1, and the prepared polyurea coating is defined as polyurea coating C2.

[0128] Comparative Example 3

[0129] The difference between Comparative Example 3 and Example 1 is that in step S200, 2.16 parts of reduced graphene oxide (particle size 15 μm) are added to the first mixture and then stirred and dispersed. The remaining operations and component parameters are the same as those in Example 1, and the prepared polyurea coating is defined as polyurea coating C3.

[0130] Comparative Example 4

[0131] The difference between Comparative Example 4 and Example 1 is that in step S200, 2.16 parts of reduced graphene oxide (particle size 30 μm) are added to the first mixture and then stirred and dispersed. The remaining operations and component parameters are the same as those in Example 1, and the prepared polyurea coating is defined as polyurea coating C4.

[0132] Comparative Example 5

[0133] The difference between Comparative Example 5 and Example 1 is that in step S200, 2.16 parts of multi-walled carbon nanotubes are added to the first mixture and then stirred and dispersed. The remaining operations and component parameters are the same as those of Example 1, and the prepared polyurea coating is defined as polyurea coating C5.

[0134] Comparative Example 6

[0135] The difference between Comparative Example 6 and Example 1 is that in step S200, 2.16 parts of carbon nanotube slurry (solid content of carbon nanotube slurry is 5 wt%) is added to the first mixture and then stirred and dispersed. The remaining operations and component parameters are the same as those of Example 1, and the prepared polyurea coating is defined as polyurea coating C6.

[0136] Comparative Example 7

[0137] The difference between Comparative Example 7 and Example 1 is that in step S200, 2.16 parts of silver-coated copper powder (containing 3% silver) is added to the first mixture and then stirred and dispersed. The remaining operations and component parameters are the same as those of Example 1, and the prepared polyurea coating is defined as polyurea coating C7.

[0138] Comparative Example 8

[0139] The difference between Comparative Example 8 and Example 1 is that the antistatic agent and MOFs material are missing, and in step S200, 0.6 parts of single-walled carbon nanotubes are added to the first mixture and then stirred and dispersed. The remaining operations and processes are the same as those in Example 1, and the prepared polyurea coating is defined as polyurea coating C8.

[0140] Comparative Example 9

[0141] The difference between Comparative Example 9 and Example 1 is that the amount of the antistatic agent exceeds the specified range, and in step S200, after adding 0.3 parts of single-walled carbon nanotubes, 5.4 parts of the antistatic agent and 0.06 parts of the MOFs material to the first mixture, stirring and dispersing is performed. The remaining operations and component parameters are the same as those in Example 1, and the prepared MOFs-based antistatic polyurea coating is defined as polyurea coating C9.

[0142] Comparative Example 10

[0143] The difference between Comparative Example 10 and Example 1 is that the amount of MOFs material exceeds the specified range, and in step S200, after adding 0.3 parts of single-walled carbon nanotubes, 1.8 parts of antistatic agent and 0.38 parts of MOFs material to the first mixture, stirring and dispersing are performed. The remaining operations and component parameters are the same as those in Example 1, and the prepared MOFs-based antistatic polyurea coating is defined as polyurea coating C10.

[0144] Comparative Example 11

[0145] The difference between Comparative Example 11 and Example 1 is that: MOFs material is missing, and in step S200, 0.3 parts of single-walled carbon nanotubes and 1.8 parts of antistatic agent are added to the first mixture, followed by stirring and dispersion. The remaining operations and component parameters are the same as those of Example 2, and the prepared polyurea coating is defined as polyurea coating C11.

[0146] Comparative Example 12

[0147] The difference between Comparative Example 12 and Example 1 is that the MOFs material is replaced with zeolite, and in step S200, 0.3 parts of single-walled carbon nanotubes, 1.8 parts of antistatic agent and 0.06 parts of zeolite are added to the first mixture, and then stirred and dispersed. The remaining operations and component parameters are the same as those in Example 1, and the prepared polyurea coating is defined as polyurea coating C12.

[0148] Comparative Example 13

[0149] The difference between Comparative Example 13 and Example 1 is that the length and diameter of the single-walled carbon nanotubes exceed the specified range. In step S200, 0.3 parts of single-walled carbon nanotubes (ultra-high purity single-walled carbon nanotubes SWCNT, model: JC-NTS01, length>90μm, outer diameter 1.5-1.8nm), polyether-L44 (Haian (Linyi) Guoli Chemical Co., Ltd.), and 0.06 parts of MOFs material (prepared in Example 1) are added to the first mixture and stirred and dispersed. The remaining operations and component parameters are the same as those in Example 1, and the prepared MOFs-based antistatic polyurea coating is defined as polyurea coating C13.

[0150] The polyurea coatings 1-7 prepared in the above examples 1-7 and the polyurea coatings C1-C13 prepared in the comparative examples 1-13 were coated on the surface of the same substrate to form coatings of the same thickness, and then dried to perform performance tests. Figure 4 The coating formed by the polyurea coating 1 prepared in Example 1 is schematically shown. The performance test includes:

[0151] Surface resistance: Use HIMA AS982 surface resistance tester or Japan Sanliang SR110 tester for measurement, and take the average value of three points of the surface resistance of the coating on the same sample as the test result.

[0152] Flame retardant performance: tested according to UL94 standard.

[0153] Adhesion grade: Tested in accordance with GB / T9286-1998.

[0154] Weather resistance: Tested in accordance with GB / T16259, using a UVB-313 accelerated weathering test chamber.

[0155] Pencil hardness grade: Tested according to the pencil method GBT6739-1996.

[0156] Impact strength: Tested in accordance with GB / T1732.

[0157] Salt spray resistance: Tested in accordance with GB / T1771-2007.

[0158] Stability: The surface resistance of the sample coating is measured after 300 days of storage.

[0159] Viscosity: Use Brookfield DV2T viscometer to measure the viscosity of the coating at 25°C, and take the average of three viscosities as the test result.

[0160] The test results are shown in Table 1.

[0161] Table 1. Summary of test results of polyurea coatings prepared in Examples and Comparative Examples

[0162]

[0163] The antistatic performance can be evaluated by the surface resistance value of the coating formed by the polyurea coating; the lower the surface resistance value, the better the conductive performance of the coating to static electricity, that is, the better the antistatic effect. Conversely, the higher the surface resistance value, the worse the antistatic performance. As shown in Table 1, from the above experimental results, it can be seen that compared with the test results of the comparative example, the surface resistance of the coating prepared by the polyurea coatings 1-7 obtained by the preparation method of the MOFs-based antistatic polyurea coating provided by the present disclosure is 8×10 6Ω or less, with excellent antistatic properties. At the same time, by doping with porous MOFs materials, the electrostatic conductivity of the prepared coating is improved while the viscosity of the coating at room temperature is greatly reduced.

[0164] Compared with Example 1, Comparative Examples 1-4 do not add antistatic fillers (such as conductive single-walled carbon nanotubes, antistatic agents and MOFs materials), and only add carbon black with larger particle size and redox graphene of different sizes. Due to the poor dispersion of carbon black and redox graphene in the first mixture, the viscosity of the coating increases, and no uniform conductive and thermal conductive network is formed. The surface resistance of the coating is significantly lower than that of Example 1.

[0165] Comparative Examples 5-7 are compared with Example 1. Multi-walled carbon nanotubes, carbon nanotube slurry with low solid content and silver-coated copper powder are added. The dispersion of these components is poor, which increases the viscosity of the coating. At the same time, due to the small amount of addition and the lack of MOFs material-mediated connection, a uniform conductive and thermal conductive network cannot be formed, and the surface resistance of the coating is also lower than that of Example 1.

[0166] Compared with Example 1, Comparative Example 8 adds an excess of single-walled carbon nanotubes; Comparative Example 9 adds an excess of antistatic agent; Comparative Example 10 adds an excess of MOFs material compared with Example 1. From the test results in Table 1, it can be seen that the mechanical properties of the prepared polyurea coatings C8, C9 and C10 are slightly improved compared with polyurea coating 1, but the surface resistance and coating viscosity are greatly increased, that is, the antistatic property is reduced. This is because excessive addition of antistatic fillers will form agglomerates in the polyurea coating, causing the antistatic fillers to be unevenly dispersed in the resin matrix (first mixture), increasing the resistance of the resin matrix, thereby affecting the effective transmission of electrostatic charges by the conductive network, and the antistatic performance of the coating formed by the polyurea coating is reduced, and the viscosity will also increase, which in turn affects the processing performance of the coating.

[0167] Compared with Example 1, in Comparative Examples 11-12, due to the absence of MOFs materials, the conductive network in the coating formed by the polyurea coating is incomplete, resulting in a significant increase in surface resistance. At the same time, due to the lack of MOFs materials, the single-walled carbon nanotubes and antistatic agents have poor compatibility with the resin and poor dispersibility, which reduces the antistatic properties of the coating.

[0168] Comparative Example 13 Compared with Example 1, the conductivity of the coating formed by the polyurea coating C13 is reduced. This may be because the single-walled carbon nanotubes are relatively long, and the dispersion effect in the formed polyurea coating is poor, making it difficult to form a conductive network. By using shorter single-walled carbon nanotubes, the reinforcement structure formed in the coating is more uniform and dense, which helps to improve the mechanical properties of the coating, such as tensile strength and tear strength. At the same time, the conductive network formed by the shorter single-walled carbon nanotubes in the coating may be more complete. As the length of the single-walled carbon nanotubes used increases, the conductivity of the formed coating will also decrease.

[0169] It should be noted that, although the steps of the method for preparing the MOFs-based antistatic polyurea coating in the present disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in this specific order, or that all the steps shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps, etc.

[0170] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A MOFs-based antistatic agent, characterized in that: The MOFs-based antistatic agent comprises, by mass, 0.2 to 1 parts of single-walled carbon nanotubes, 1.5 to 4 parts of antistatic agent and 0.05 to 0.3 parts of MOFs material, wherein the metal salt involved in the MOFs material is acetylacetone metal salt, and the ligand is 2-methylimidazole; The antistatic agent is at least one of a polyether antistatic agent, a polyacrylate antistatic agent, a sulfonic acid derivative antistatic agent, and a polyquaternary ammonium salt antistatic agent.

2. A MOFs-based antistatic polyurea coating, characterized in that: It includes component A and component B, and the mass ratio of component A to component B is (2-3):1; According to the mass, the component A comprises: 40 to 60 parts of polyaspartic acid ester resin, 0.4 to 1.2 parts of dispersant, 14 to 25 parts of titanium dioxide, 0.4 to 1.4 parts of defoamer, 0.4 to 0.8 parts of leveling agent, and 1.75 to 5.3 parts of the MOFs-based antistatic agent according to claim 1; The B component includes an isocyanate curing agent, and the viscosity of the isocyanate curing agent is 30 to 100 mPa·s.

3. The method for preparing the MOFs-based antistatic polyurea coating according to claim 2, characterized in that: The following steps are involved: S100, mixing polyaspartic acid ester resin, dispersant, titanium dioxide, defoamer, and leveling agent, and stirring and dispersing at 1000 rpm to 2000 rpm / min for 5 min to 10 min to obtain a first mixture; S200, adding single-walled carbon nanotubes and antistatic agent to the first mixture, stirring and dispersing at 3800rpm-4600rpm / min for 15min-25min; then adding MOFs material thereto, stirring and dispersing at 3800rpm-4600rpm / min for 10min-15min; finally stirring and dispersing at 200rpm-400rpm / min for 5min-10min to obtain component A; S300, mixing component A with component B, stirring and dispersing them at 3800 rpm to 4600 rpm / min for 10 min to 15 min, to obtain a MOFs-based antistatic polyurea coating.

4. The method for preparing the MOFs-based antistatic polyurea coating according to claim 2, characterized in that: The preparation process of the MOFs material comprises the following steps: S1, mixing the metal salt and the organic ligand in a molar ratio of 1:(2-3), stirring and passing through a 50-100 mesh sieve to obtain a precursor powder; S2, evenly spreading the precursor powder obtained in step S1 in a porcelain boat, and then placing the porcelain boat in a tube furnace for heating treatment to obtain MOFs raw materials; S3. After ball milling the MOFs raw material for 1 to 3 hours, the raw material is sieved through a 100-200 mesh sieve to obtain the MOFs material.

5. The method for preparing the MOFs-based antistatic polyurea coating according to claim 3, characterized in that: In step S2, the heating treatment includes: A protective atmosphere is introduced into the tubular furnace at a gas flow rate of 150 to 300 cc / min. At the same time, the tubular furnace is heated to 100 to 120°C at a heating rate of 2 to 4°C / min, and the gas inlet valve is closed; The tube furnace is evacuated to a vacuum state, and then the temperature is raised to 200-225°C at a heating rate of 2-3°C / min, and kept at this temperature for 3-5 hours; After the heat preservation under vacuum is completed, the furnace is cooled to room temperature to obtain MOFs raw materials.

6. The method for preparing the MOFs-based antistatic polyurea coating according to claim 3, characterized in that: In step S3, during ball milling, the rotation speed is 150 rpm / min to 250 rpm / min, the mass ratio of MOFs raw materials to ball milling beads is 0.15 to 0.25; and the diameter of the ball milling beads is 0.3 to 10 mm.

7. The method for preparing the MOFs-based antistatic polyurea coating according to any one of claim 3, characterized in that: The single-walled carbon nanotube has a length of 5 to 20 μm and a diameter of 1 to 1.8 nm.

8. The method for preparing the MOFs-based antistatic polyurea coating according to any one of claim 3, characterized in that: The isocyanate curing agent is 4,4'-dicyclohexylmethane diisocyanate.

9. The method for preparing the MOFs-based antistatic polyurea coating according to any one of claim 3, characterized in that: The metal salt of acetylacetonate is zinc acetylacetonate or cobalt acetylacetonate.

10. The method for preparing the MOFs-based antistatic polyurea coating according to any one of claim 3, characterized in that: The dispersant is at least one of polymethyl acrylate, polybutyl acrylate, polyethyl acrylate and cross-linked polyacrylic acid; The leveling agent is polyether modified siloxane.

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