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

Abstract

The application provides a 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 comprises, according to mass, 0.2-1 parts of single-walled carbon nanotubes, 1.5-4 parts of an antistatic agent and 0.05-0.3 parts of a MOFs material.The metal salt involved in the MOFs material is an acetylacetone metal salt, and the 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 polyquaternary ammonium salt type antistatic agent.The MOFs-based antistatic agent provided by the application is applied to the polyurea coating, improves the antistatic property of the polyurea coating, reduces the viscosity of the polyurea coating, and the coating strength of the polyurea coating is relatively high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyurea coating, in particular to a MOFs-based antistatic agent, a polyurea coating and a preparation method thereof. BACKGROUND

[0002] Polyurea coating is a new type of solvent-free and pollution-free, two-component rapid curing green coating, mainly composed of polyaspartic ester resin and isocyanate. Through the reaction of the secondary amine group (-NH-) on the polyaspartic ester resin and the -NCO group in the isocyanate, a urea bond (-NHCONH-) is formed, and a three-dimensional network structure is rapidly cross-linked and cured. Polyurea coating exhibits excellent chemical stability, and has good flexibility, high strength, corrosion resistance, aging resistance and other characteristics.

[0003] Antistatic polyurea coating retains the original excellent performance of polyurea coating, and by introducing antistatic agents or conductive fillers and other components, the surface resistivity of the coating is significantly reduced, the electric charge can be quickly released, the surface charge accumulation is effectively avoided, and the antistatic function of the coating is realized. Antistatic coating has been widely used in aerospace industry, petrochemical industry, electronic manufacturing industry, high-end equipment manufacturing field and plastic packaging industry and other important fields.

[0004] However, the addition amount of conductive fillers or antistatic agents used in most antistatic coating researches is relatively high (generally more than 5%). On the one hand, too much conductive filler and antistatic agent can easily cause "agglomeration" in the polymer matrix, which will adversely affect the mechanical and optical properties of the material. On the other hand, a large amount of conductive fillers and antistatic agents will significantly increase the viscosity of the resin, and higher temperature and pressure are required during construction to achieve 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. Carbon nanotubes are modified by a PVP dispersant to enable uniform dispersion of the carbon nanotubes in the water-based polyurea coating, and an antistatic polyurea coating is obtained. The patent improves the compatibility of carbon nanotubes with polyurea coating by using a polyvinylpyrrolidone dispersant containing hydrophilic carboxyl and amino groups to enhance the interfacial interaction between carbon nanotubes and polyurea. However, this preparation process is complicated, 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 problem to be solved to reasonably control the addition amount of conductive fillers and antistatic agents in antistatic polyurea coating 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 background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

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

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

[0010] The antistatic agent is at least one of the following: polyether-type antistatic agent, polyacrylate-type antistatic agent, sulfonic acid derivative-type antistatic agent, and polyquaternary ammonium salt-type antistatic agent.

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

[0012] Component A comprises, by weight, 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 defoamer, 0.4-0.8 parts of leveling agent, and 1.75-5.3 parts of MOFs-based antistatic agent;

[0013] Component B includes an isocyanate curing agent with a viscosity of 30~100 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. After mixing polyaspartic acid ester resin, dispersant, titanium dioxide, defoamer, and leveling agent, stir and disperse at 1000 rpm to 2000 rpm / min for 5 min to 10 min to obtain the first mixture;

[0016] S200. Add single-walled carbon nanotubes and an antistatic agent to the first mixture, and stir and disperse at 3800 rpm to 4600 rpm / min for 15 min to 25 min; then add MOF materials and stir and disperse at 3800 rpm to 4600 rpm / min for 10 min to 15 min; finally, stir and disperse at 200 rpm to 400 rpm / min for 5 min to 10 min to obtain component A.

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

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

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

[0020] S2, uniformly 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 a MOFs raw material;

[0021] S3, ball milling the MOFs raw material for 1-3 h, and then passing through a 100-200 mesh sieve to obtain the MOF material.

[0022] On the basis of the above technical scheme, preferably, in step S2, the heating treatment comprises:

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

[0024] The tube furnace is pumped to a vacuum state, and then heated to 200-225°C at a heating rate of 2-3°C / min, and held for 3-5 h;

[0025] After the vacuum holding is completed, the furnace is cooled to room temperature to obtain the MOFs raw material. On the basis of the above technical scheme, preferably, in step S3, the rotation speed is 150 rpm / min-250 rpm / min during ball milling, the mass ratio of the raw material to the ball milling beads is 0.15-0.25, and the diameter of the ball milling beads is 0.3-10 mm.

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

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

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

[0029] Preferably, the dispersant is a polyacrylic dispersant.

[0030] The polyacrylic dispersant is at least one of poly(methyl acrylate), poly(butyl acrylate), poly(ethyl acrylate) and cross-linked poly(acrylic acid).

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

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

[0033] 1. The novel MOFs-based antistatic agent comprises several different micro-nano antistatic fillers, including single-walled carbon nanotubes, polymeric permanent liquid antistatic agents and MOFs materials. The nanoscale MOFs material has a hydrophilic group and can be adsorbed on the single-walled carbon nanotubes, improving the compatibility of the carbon nanotubes with the resin, so that the novel antistatic agent has good dispersibility in the resin and reduces the viscosity of the coating; at the same time, the nanoscale MOFs material can be filled in the conductive network built by the fibrous one-dimensional nanomaterial single-walled carbon nanotubes and the polymeric permanent liquid antistatic agent, and synergistically acts with the single-walled carbon nanotubes and the polymeric permanent liquid antistatic agent having excellent conductivity coefficient, so as to improve the antistatic performance of the novel antistatic agent.

[0034] 2. In the preparation of the MOFs-based antistatic polyurea coating, the method of adding the novel MOFs-based antistatic agent in stages is adopted. First, long-sized single-walled carbon nanotubes and polymeric permanent liquid antistatic agents are added to the polyaspartic ester resin, and both are uniformly dispersed in the polyaspartic ester resin to build a basic conductive network; second, nanoscale MOF materials are added, which can be adsorbed on the single-walled carbon nanotubes and filled in the conductive network and polyaspartic ester resin material that has been built, connecting the remaining dispersed single-walled carbon nanotubes and antistatic agents, ensuring that all fillers can be uniformly dispersed in the polyaspartic ester resin material, and finally forming a 3D continuous and uniform conductive network that is interconnected, so as to make the polyurea coating have better antistatic effect. At the same time, the antistatic performance of the coating layer formed by the polyurea coating can be improved with a small amount of MOFs-based antistatic agent, the viscosity of the coating layer is reduced, and the production cost and construction cost of the polyurea coating are reduced.

[0035] 3. The MOFs material adopted in the application is prepared by the all-solid-phase synthesis process independently created by the Functional Hybrid Materials Laboratory of Wuhan University of Technology, and has the advantages of short synthesis cycle, high yield, mass production, green and pollution-free, etc.

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

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

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

[0039] Figure 2 For some embodiments of the present disclosure, a flow chart of the preparation of the MOFs-based antistatic polyurea coating.

[0040] Figure 3 For an embodiment of the present disclosure, a schematic diagram of the MOFs-based antistatic polyurea coating.

[0041] Figure 4 For an embodiment of the present disclosure, a schematic diagram of the coating layer formed by the MOFs-based antistatic polyurea coating. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

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

[0044] In this embodiment, by adding a MOFs material in 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 the formation of a uniform and continuous conductive network in the polyurea coating, and realizes the stability of the conductive network. See Figure 1The red line with the arrow shows a conductive pathway formed by single-walled carbon nanotubes, antistatic agents, and MOF materials in the polyurea coating. Simultaneously, the porous structure of the MOF materials can adsorb moisture and gases from the environment, reducing the concentration of charge on the coating surface and acting as a charge shield and dispersion agent.

[0045] In some embodiments of this disclosure, the antistatic agent can be a polymeric permanent liquid antistatic agent. Polymeric permanent liquid antistatic agents have a long-lasting antistatic effect and can form a three-dimensional ion-conducting network structure in the polyurea coating matrix, reducing the volume resistivity of the polyurea coating matrix itself, and are less affected by ambient humidity.

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

[0047] For example, the polyether-type antistatic agent can be polyether-L44 produced by Haian (Linyi) Guoli Chemical Co., Ltd., whose main component is propylene glycol block polyether.

[0048] For example, the polyacrylate antistatic agent can be the JL-WT1 type or JL-WT1 type produced by Shandong Juli Antistatic Technology Co., Ltd., whose main component is polyallylamine hydrochloride.

[0049] For example, a sulfonic acid derivative type antistatic agent can be sodium dodecylbenzenesulfonate produced by Jinan Shengming Chemical Co., Ltd.

[0050] For example, the polyquaternary ammonium salt type antistatic agent can 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] This disclosure also provides a MOFs-based antistatic polyurea coating, comprising component A and component B, wherein the mass ratio of component A to component B is (2~3):1; component A comprises, 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 defoamer, and 0.4~0.8 parts of leveling agent; the MOFs-based antistatic agent comprises, by mass, 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; component B comprises an isocyanate curing agent, wherein the viscosity of the isocyanate curing agent is 30~100 mPa·s.

[0052] In this embodiment, the addition of MOFs material increases the formation of conductive network in the polyurea coating, and the polyurea coating can achieve higher antistatic property at a lower amount of antistatic filler (single-walled carbon nanotubes, antistatic agent and MOFs material). The amount of antistatic filler is not too high, which avoids the agglomeration of polyaspartic acid resin matrix and adversely affects the mechanical and optical properties of the polyurea coating. At the same time, too much antistatic filler is avoided, which increases the viscosity of the polyaspartic acid resin, and higher temperature and pressure conditions are required to achieve ideal spraying fluidity and forming effect during use, increasing the construction difficulty and cost.

[0053] In an 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 Feiyangjun New Material Co., Ltd.

[0054] In an embodiment of the present disclosure, the length of the single-walled carbon nanotube is 5-20 µm, and the diameter of the single-walled carbon nanotube along the cross section perpendicular to the length direction is 1-1.8 nm. The single-walled carbon nanotube can form a good conductive network in the matrix of the polyurea coating and has good conductive performance. 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; and 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 Okoshi Ai Trade (Shenzhen) Co., Ltd.

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

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

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

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

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

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

[0062] S2, uniformly 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 a MOFs raw material;

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

[0064] The MOFs material is prepared by a full solid-phase synthesis process in this embodiment. The preparation process is solvent-free, time-saving, high-yield, and pollution-free. The MOFs material prepared is added to the conductive network of the polyaspartic acid ester resin, which can provide more contact points for the single-walled carbon nanotubes and the antistatic agent, and build a more continuous, uniform, and stable conductive network. In addition, based on the hydrophilicity of the MOFs material, the MOFs material is adsorbed on the single-walled carbon nanotubes and filled in the polyaspartic acid ester resin, which improves the compatibility of the single-walled carbon nanotubes and the polyaspartic acid ester resin and the dispersibility of the single-walled carbon nanotubes in the polyaspartic acid ester resin, and prevents the single-walled carbon nanotubes and the antistatic agent from agglomerating in the polyaspartic acid ester resin, thereby reducing the viscosity of the coating and improving the antistatic property.

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

[0066] In an embodiment of the present disclosure, in step S2, the heating treatment comprises: introducing a protective atmosphere into the tube furnace at a gas flow rate of 150-300 cc / min, and heating the tube furnace to 100-120°C at a heating rate of 2-4°C / min, and then closing the gas inlet valve; vacuumizing the tube furnace, and then heating the tube furnace to 200-225°C at a heating rate of 2-3°C / min, and holding for 3-5 h; and after the holding under vacuum, cooling the tube furnace to room temperature to obtain the MOFs raw material.

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

[0068] For example, before vacuumizing the tube furnace, the heating rate of the tube 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; and the holding time after heating can be 3 h, 3.5 h, 4 h, 4.5 h or 5 h.

[0069] In an embodiment of the present disclosure, in step S3, during ball milling, the rotation speed is 150-250 rpm / min, the mass ratio of the MOFs raw material to the ball milling beads is 0.15-0.25, and the diameter of the ball milling beads is 0.3-10 mm. Too many ball milling beads can cause excessive grinding of the MOFs raw material and increase energy consumption; on the contrary, too much MOFs raw material can cause insufficient grinding. If the diameter of the ball milling beads is too large, the impact force on the MOFs raw material is large, which can easily crush the MOFs raw material, but it is difficult to grind finely and there are dead angles in grinding. If the diameter of the ball milling beads is too small, the impact frequency is high, which is good for grinding the small MOFs raw material, but the impact force is small, which is not good for grinding the large MOFs raw material.

[0070] The present disclosure also provides a preparation method of the MOFs-based antistatic polyurea coating as described above, as shown in the following scheme: Figure 2 The method comprises the following steps:

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

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

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

[0074] In the preparation of the polyurea coating, the single-walled carbon nanotubes with excellent electrical conductivity, the high-molecular liquid antistatic agent, and the MOFs material with a special structure are uniformly dispersed in the curing system of the polyaspartic ester resin by high-speed dispersion, the MOFs material with a high specific surface area and a multi-pore structure acts as a bridge to connect the basic conductive network built by the fibrous one-dimensional nanomaterial single-walled carbon nanotubes and the low-molecular chain high-molecular liquid antistatic agent, which ensures that all the antistatic fillers are uniformly dispersed in the polyaspartic ester resin and can form a complete and continuous three-dimensional conductive network, improving the comprehensive performance of the material. At the same time, the antistatic performance of the coating can be improved, the viscosity of the coating can be reduced, and the production cost and construction cost of the coating can be reduced with a small amount of fillers.

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

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

[0077] Example 1

[0078] (1) Preparation of MOFs material

[0079] S1, zinc acetylacetonate and 2-methylimidazole were placed in a three-necked flask in a molar ratio of 1:3, and the mixture was stirred manually for 5 min to achieve a fine powder state with uniform color and no obvious particles, and then sieved through a 50-mesh sieve to obtain a precursor powder.

[0080] S2, the precursor powder obtained in step S1 was uniformly spread in a porcelain boat, and the porcelain boat was placed in a tube furnace for pyrolysis treatment to obtain MOFs raw materials. The heating treatment included: (1) a protective atmosphere was introduced into the tube furnace at a gas flow rate of 200 cc / min, and the protective atmosphere was argon; at the same time, the tube furnace was heated to 100°C at a heating rate of 3°C / min, and the gas inlet valve was closed; (2) the tube furnace was evacuated to a vacuum state, and then heated to 200°C at a heating rate of 2.5°C / min, and held for 4 h; (3) after the holding under vacuum was completed, the furnace was cooled to room temperature to obtain the MOFs raw materials.

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

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

[0083] S100, 40 parts of polyaspartic ester resin F420 (Shenzhen Feiyangjun New Material Co., Ltd.), 1 part of dispersant polyacrylate (PMA), 20 parts of titanium white, 1 part of defoamer BYK-A535 (Bayer, Germany), and 0.5 parts of leveling agent BYK-302 (Bayer, Germany) were sequentially added to the dispersion tank of a high-speed disperser, and stirred and dispersed for 10 min at a speed of 2000 rpm / min to uniformly disperse the additives in the polyaspartic ester resin, to obtain a first mixture. The dispersion tank of the high-speed disperser has a cooling system, so that the temperature in the dispersion tank during stirring and dispersion is 15-25°C.

[0084] S200, 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 direction is 1 nm) and 1.8 parts of antistatic agent polyether-L44 (Hai'an (Linyi) Guolike Chemical Co., Ltd.) were added to the first mixture, the speed of the high-speed disperser was adjusted to 4000 rpm / min, and stirred and dispersed for 25 min, then 0.06 parts of MOFs material (prepared in this example) was added, the speed of the high-speed disperser was adjusted to 4000 rpm / min, and stirred and dispersed for 15 min; then the speed of the high-speed disperser was adjusted to 200 rpm / min, and stirred and dispersed for 5 min for defoaming to obtain component A.

[0085] S300, the A component and the B component (curing agent: 4,4'-dicyclohexyl methane diisocyanate) are added into the dispersion tank of the high-speed dispersion machine in batches according to the mass ratio of 2:1, and stirred and dispersed at 4000 rpm / min for 10 min to obtain the MOFs-based antistatic polyurea coating, which is defined as polyurea coating 1, as shown in Figure 3 .

[0086] Example 2

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

[0088] Example 3

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

[0090] Example 4

[0091] (1) Preparation of MOFs material

[0092] S1, zinc acetylacetonate and 2-methylimidazole are placed in a three-necked flask in a molar ratio of 1:2.2, and stirred manually for 5 min to obtain a fine powder state with uniform color and no obvious particles, and then sieved through a 100-mesh sieve to obtain a precursor powder.

[0093] S2, the precursor powder obtained in step S1 is uniformly spread in a porcelain boat, and then the porcelain boat is placed in a tube furnace for pyrolysis treatment to obtain a MOFs raw material. The heating treatment includes: (1) a protective atmosphere is introduced into the tube furnace, the gas flow rate is 150 cc / 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 gas inlet valve is closed; (2) the tube furnace is pumped to a vacuum state, and then heated to 225°C at a heating rate of 2°C / min, and kept for 3 h; (3) after the vacuum heat preservation is completed, the furnace is cooled to room temperature to obtain the MOFs raw material.

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

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

[0096] S100, 54 parts of polyaspartic ester resin F520 (Shenzhen Feiyangjun New Material Co., Ltd.), 1 part of dispersant polybutyl acrylate (PBA), 18 parts of titanium white, 1.4 parts of defoamer BYK-A501 (Germany BYK), 0.6 parts of leveling agent BYK-333 (Germany BYK) were added into the dispersion tank of a high-speed disperser in turn, and stirred and dispersed at a speed of 2000 rpm / min for 10 min, so that the additives were uniformly dispersed in the polyaspartic ester resin to obtain a first mixture. The dispersion tank of the high-speed disperser has a cooling system, so that the temperature in the dispersion tank during stirring and dispersion is 15-25°C.

[0097] S200, 0.3 parts of single-walled carbon nanotubes (average length of single-walled carbon nanotubes is 10 µm, average diameter of cross section perpendicular to length direction is 1.6 nm) and 3.7 parts of antistatic agent SN (Hubei Kovod Chemical Co., Ltd.) were added into the first mixture, the speed of the high-speed disperser was adjusted to 4000 rpm / min, and stirred and dispersed for 25 min. Then 0.24 parts of MOFs material (prepared in this example) was added, the speed of the high-speed disperser was adjusted to 4000 rpm / min, and stirred and dispersed for 15 min. Then the speed of the high-speed disperser was adjusted to 200 rpm / min, and stirred and dispersed for 5 min for defoaming to obtain component A.

[0098] S300, component A and component B (curing agent: 4,4'-dicyclohexyl methane diisocyanate) were added into the dispersion tank of a high-speed disperser in batches according to a mass ratio of 2.7:1, and stirred and dispersed at a speed of 4000 rpm / min for 10 min to obtain MOFs-based antistatic polyurea coating, which is defined as polyurea coating 4.

[0099] Example 5

[0100] MOFs material was prepared

[0101] S1, cobalt acetylacetonate and 2-methylimidazole were placed in a three-necked flask according to a molar ratio of 1:2.8, and stirred manually for 5 min to obtain a fine powder state with uniform color and no obvious particles, and then sieved through an 80-mesh sieve to obtain a precursor powder.

[0102] S2, spread the precursor powder obtained in step S1 evenly in a porcelain boat, and then place the porcelain boat in a tube furnace for pyrolysis treatment to obtain MOFs raw material. The heating treatment comprises: (1) introduce a protective atmosphere into the tube furnace, the gas flow rate is 150 cc / min, 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 gas inlet valve is closed; (2) vacuumize the tube furnace, and then heat to 210°C at a heating rate of 2.2°C / min, and keep for 4h; (3) after the vacuum heat preservation is completed, cool down to room temperature with the furnace, and obtain the MOFs raw material.

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

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

[0105] S100, add 60 parts of polyaspartic acid ester resin F220 (Shenzhen Feiyangjun New Material Co., Ltd.), 1.2 parts of dispersant polyacrylic acid ethyl ester, 25 parts of titanium white, 1.4 parts of defoaming agent BYK-A555 (Germany BYK), and 0.8 parts of leveling agent BYK-335 (Germany BYK) into a dispersion tank of a high-speed dispersion machine in sequence, and stir and disperse under the condition that the rotation speed of the high-speed dispersion machine is 1500 rpm / min and the stirring and dispersing time is 8 min, so that the additives are uniformly dispersed in the polyaspartic acid ester resin, and a first mixture is obtained. The dispersion tank of the high-speed dispersion machine 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 5µm, and the average diameter of the cross section perpendicular to the length direction is 1.8 nm) and 4 parts of antistatic agent SN (Hubei Kovod Chemical Co., Ltd.) into the first mixture, adjust the rotation speed of the high-speed dispersion machine to 4600 rpm / min, stir and disperse for 20 min, then add 0.3 parts of the MOFs material (prepared in this embodiment) into the mixture, adjust the rotation speed of the high-speed dispersion machine to 4600 rpm / min, stir and disperse for 10 min, then adjust the rotation speed of the high-speed dispersion machine to 300 rpm / min, stir and disperse for 10 min for defoaming, and obtain component A.

[0107] S300, add component A and component B (curing agent: 4,4'-dicyclohexyl methane diisocyanate) into the dispersion tank of the high-speed dispersion machine in batches according to a mass ratio of 3:1, stir and disperse for 10 min under the condition that the rotation speed is 4000 rpm / min, and obtain MOFs-based antistatic polyurea coating, which is defined as polyurea coating 5.

[0108] Example 6

[0109] (1) Preparation of MOFs material

[0110] S1, zinc acetylacetonate and 2-methylimidazole were placed in a three-necked flask in a molar ratio of 1:2, and the mixture was stirred manually for 5 min to achieve a fine powder state with uniform color and no obvious particles, and then sieved through a 60-mesh sieve to obtain a precursor powder.

[0111] S2, the precursor powder obtained in step S1 was uniformly spread in a porcelain boat, and the porcelain boat was placed in a tube furnace for pyrolysis treatment to obtain a MOFs raw material. The heating treatment included: (1) a protective atmosphere was introduced into the tube furnace at a gas flow rate of 300 cc / min, and the protective atmosphere was argon; at the same time, the tube furnace was heated to 110°C at a heating rate of 2°C / min, and the gas inlet valve was closed; (2) the tube furnace was evacuated to a vacuum state, and then heated to 200°C at a heating rate of 3°C / min, and held for 3.5 h; (3) after the vacuum holding was completed, the furnace was cooled to room temperature, and the MOFs raw material was obtained.

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

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

[0114] S100, 40 parts of polyaspartic acid ester resin F420 (Shenzhen Feiyangjun New Material Co., Ltd.), 1 part of dispersant polyacrylate (PMA), 20 parts of titanium white, 0.4 parts of defoamer BYK-A535 (Germany BYK), and 0.4 parts of leveling agent BYK-302 (Germany BYK) were sequentially added to the dispersion tank of a high-speed dispersion machine, and stirred and dispersed for 5 min at a speed of 1000 rpm / min to uniformly disperse the additives in the polyaspartic acid ester resin, to obtain a first mixture. The dispersion tank of the high-speed dispersion machine has a cooling system, so that the temperature in the dispersion tank during stirring and dispersion is 15-25°C.

[0115] S200, 0.2 parts of single-walled carbon nanotubes (average length of single-walled carbon nanotubes is 10 pm, average diameter of cross section perpendicular to length direction is 1.5 nm), 1.5 parts of antistatic agent polyether-L44 (Hai'an (Linyi) Guolili Chemical Co., Ltd.) were added in the first mixture, the rotating speed of high-speed dispersion machine was adjusted to 3800 rpm / min, and stirring and dispersion were performed for 15 min, then 0.05 parts of MOFs material (prepared in the embodiment) was added, the rotating speed of high-speed dispersion machine was adjusted to 3800 rpm / min, and stirring and dispersion were performed for 10 min; then the rotating speed of high-speed dispersion machine was adjusted to 400 rpm / min, defoaming was performed by stirring and dispersion for 8 min, and A component was obtained.

[0116] S300, A component and B component (curing agent: 4,4'-dicyclohexyl methane diisocyanate) were added into a dispersion tank of high-speed dispersion machine in batches according to a mass ratio of 2.5:1, stirring and dispersion were performed for 10 min under the condition of 4000 rpm / min, and MOFs-based antistatic polyurea coating was obtained, which was defined as polyurea coating 6.

[0117] Example 7

[0118] S1, zinc acetylacetonate and 2-methylimidazole were placed in a three-necked flask according to a molar ratio of 1:2.6, manual stirring was performed for 5 min to obtain a fine powder state with uniform color and no obvious particles, and the precursor powder was obtained by passing through a 70-mesh sieve.

[0119] S2, the precursor powder obtained in step S1 was uniformly spread in a porcelain boat, and the porcelain boat was placed in a tube furnace for pyrolysis treatment to obtain MOFs raw material. The heating treatment included: (1) a protective atmosphere was introduced into the tube furnace, the gas flow rate was 250 cc / min, the protective atmosphere was argon, and the tube furnace was heated to 100°C at a heating rate of 2.5°C / min, and the gas inlet valve was closed; (2) the tube furnace was pumped to a vacuum state, and then heated to 220°C at a heating rate of 2.8°C / min, and kept for 5 h; (3) after the vacuum heat preservation was completed, the furnace was cooled to room temperature, and the MOFs raw material was obtained.

[0120] S3, the MOFs raw material was ball milled at a rotating speed of 220 rpm / min (mass ratio of raw material to ball milling beads was 0.18; diameter of 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 coating

[0122] S100, 54 parts of polyaspartic ester resin F520 (Shenzhen Feiyangjun New Material Co., Ltd.), 0.4 parts of dispersant polybutyl acrylate (PBA), 14 parts of titanium white, 1.4 parts of defoamer BYK-A501 (Germany BYK), and 0.6 parts of leveling agent BYK-333 (Germany BYK) were sequentially added to the dispersion tank of a high-speed disperser, and stirred and dispersed at a speed of 2000 rpm / min for 10 min to uniformly disperse the additives in the polyaspartic ester resin, to obtain a first mixture. The dispersion tank of the high-speed disperser has a cooling system, so that the temperature in the dispersion tank during stirring and dispersion is 15-25°C.

[0123] S200, 0.8 parts of single-walled carbon nanotubes (average length of single-walled carbon nanotubes is 20 pm, and average diameter of the cross section perpendicular to the length direction is 1.6 nm) and 2.5 parts of antistatic agent SN (Hubei Kovod Chemical Co., Ltd.) were added to the first mixture, the speed of the high-speed disperser was adjusted to 4000 rpm / min, and stirred and dispersed for 25 min. Then 0.24 parts of MOFs material (prepared in this example) was added, the speed of the high-speed disperser was adjusted to 4000 rpm / min, and stirred and dispersed for 15 min. Then the speed of the high-speed disperser was adjusted to 200 rpm / min, and stirred and dispersed for 5 min for defoaming to obtain component A.

[0124] S300, component A and component B (curing agent: 4,4'-dicyclohexyl methane diisocyanate) were added to the dispersion tank of the high-speed disperser in batches according to a mass ratio of 2.7:1, stirred and dispersed at 4000 rpm / min for 10 min to obtain MOFs-based antistatic polyurea coating, which is defined as polyurea coating 4.

[0125] The difference between Comparative Example 1 and Example 1 is that in step S200, 2.16 parts of carbon black is added to the first mixture and stirred and dispersed. The rest of the 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 pm) is added to the first mixture and stirred and dispersed. The rest of the 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] Comparative Example 3 differs from Example 1 in that in step S200, 2.16 parts of reduced graphene oxide (particle size 15 pm) is added to the first mixture and stirred to disperse. The remaining operations and component parameters are the same as Example 1, and the polyurea coating prepared is defined as polyurea coating C3.

[0130] Comparative Example 4

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

[0132] Comparative Example 5

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

[0134] Comparative Example 6

[0135] Comparative Example 6 differs from Example 1 in 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 stirred to disperse. The remaining operations and component parameters are the same as Example 1, and the polyurea coating prepared is defined as polyurea coating C6.

[0136] Comparative Example 7

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

[0138] Comparative Example 8

[0139] Comparative Example 8 differs from Example 1 in that the antistatic agent and MOFs material are absent, and in step S200, 0.6 parts of single-walled carbon nanotubes is added to the first mixture and stirred to disperse. The remaining operations and component parameters are the same as Example 1, and the polyurea coating prepared is defined as polyurea coating C8.

[0140] Comparative Example 9

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

[0142] Comparative Example 10

[0143] Comparative Example 10 differs from Example 1 in that the amount of MOFs material exceeds the defined range, 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 is performed. The remaining operations and component parameters are the same as in Example 1, the MOFs-based antistatic polyurea coating obtained in the preparation is defined as polyurea coating C10.

[0144] Comparative Example 11

[0145] Comparative Example 11 differs from Example 1 in that the MOFs material is missing, in step S200, after adding 0.3 parts of single-walled carbon nanotubes and 1.8 parts of antistatic agent to the first mixture, stirring and dispersing is performed. The remaining operations and component parameters are the same as in Example 2, the polyurea coating obtained in the preparation is defined as polyurea coating C11.

[0146] Comparative Example 12

[0147] Comparative Example 12 differs from Example 1 in that the MOFs material is replaced by a zeolite, in step S200, after adding 0.3 parts of single-walled carbon nanotubes, 1.8 parts of antistatic agent and 0.06 parts of zeolite to the first mixture, stirring and dispersing is performed. The remaining operations and component parameters are the same as in Example 1, the polyurea coating obtained in the preparation is defined as polyurea coating C12.

[0148] Comparative Example 13

[0149] Comparative Example 13 differs from Example 1 in that the length and diameter of the single-walled carbon nanotubes exceed the defined range, in step S200, after adding 0.3 parts of single-walled carbon nanotubes (ultra-high-purity single-walled carbon nanotubes SWCNT, type JC-NTS01, length > 90 pm, outer diameter 1.5-1.8 nm), polyether-L44 (Hai'an (Linyi) Guolike Chemical Co., Ltd.), 0.06 parts of MOFs material (obtained in the preparation of Example 1), stirring and dispersing is performed. The remaining operations and component parameters are the same as in Example 1, the MOFs-based antistatic polyurea coating obtained in the preparation is defined as polyurea coating C13.

[0150] The polyurea coatings 1-7 prepared in the above Examples 1-7, the polyurea coatings C1-C13 prepared in Comparative Examples 1-13 were coated on the surface of the same substrate to form a coating layer with the same thickness, and then dried and tested for performance. For example, the surface resistance of the coating layer was tested. Figure 4 The coating layer formed by the polyurea coating 1 prepared in Example 1 is schematically shown. The performance testing included:

[0151] Surface resistance: The surface resistance of the coating layer was measured using a Sigmus AS982 surface resistance tester or a Sanquan SR110 tester, and the average value of three points on the same coating surface was taken as the test result.

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

[0153] Adhesion level: tested according to GB / T9286-1998.

[0154] Weather resistance: tested according to GB / T16259, using a UVB-313 type weather resistance accelerated aging test chamber.

[0155] Pencil hardness level: tested according to the pencil method GB / T6739-1996.

[0156] Impact strength: tested according to GB / T1732.

[0157] Salt spray resistance: tested according to GB / T1771-2007.

[0158] Stability: the surface resistance of the coating layer was measured after the sample was placed for 300 days.

[0159] Viscosity: the viscosity of the coating at 25°C was measured using a Brookfield DV2T viscometer, and the average value of three viscosity values was taken 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 layer formed by the polyurea coating; the lower the surface resistance value, the better the conductive performance of the coating layer to static electricity, that is, the better the antistatic effect. Conversely, the higher the surface resistance value, the worse the antistatic performance. As can be seen from Table 1, the coating layers prepared from the polyurea coatings 1-7 obtained by the preparation method of the MOFs-based antistatic polyurea coating provided in the present disclosure in Examples 1 to 7 have a surface resistance of 8 x 10 6Ω, which has excellent antistatic properties. At the same time, by doping porous MOFs materials, the prepared coating has improved static electricity conduction properties while greatly reducing the viscosity of the coating at room temperature.

[0164] Comparative Examples 1-4 do not add antistatic fillers (such as conductive single-walled carbon nanotubes, antistatic agents and MOFs materials), but only add carbon black with a larger particle size and different size reduced graphene oxide. Due to the poor dispersibility of carbon black and reduced graphene oxide in the first mixture, the viscosity of the coating increases, and a uniform conductive and thermal network is not formed, and the surface resistance of the coating layer is significantly lower than that of Example 1.

[0165] Comparative Examples 5-7 add multi-walled carbon nanotubes, carbon nanotube paste with low solid content and silver-coated copper powder. The dispersibility 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 mediation and connection of MOFs materials, a uniform conductive and thermal network cannot be formed, and the surface resistance of the coating layer is also lower than that of Example 1.

[0166] Comparative Example 8 adds an excess of single-walled carbon nanotubes compared to Example 1; Comparative Example 9 adds an excess of antistatic agent compared to Example 1; and Comparative Example 10 adds an excess of MOFs material compared to Example 1. As can be seen from the test results in Table 1, the polyurea coatings C8, C9 and C10 prepared have slightly improved mechanical properties compared to polyurea coating 1, but the surface resistance and coating viscosity have increased significantly, that is, the antistatic property has decreased. This is because the addition of too much antistatic filler will form agglomerates in the polyurea coating, which will cause the antistatic filler to be unevenly dispersed in the resin matrix (the first mixture), increasing the resistance of the resin matrix, thereby affecting the effective transmission of static electricity by the conductive network. The antistatic properties of the coating formed by the polyurea coating decrease, and the viscosity also increases, which affects the processing performance of the coating.

[0167] Comparative Examples 11-12 do not add MOFs materials compared to Example 1, and the conductive network in the coating formed by the polyurea coating is incomplete, which causes the surface resistance to increase significantly. At the same time, the lack of MOFs materials also leads to poor compatibility and dispersion of single-walled carbon nanotubes and antistatic agents with the resin, which reduces the antistatic properties of the coating.

[0168] Comparative Example 13 and Example 1, the conductive property of the coating formed by polyurea coating C13 is decreased, which can be attributed to the fact that the single-walled carbon nanotubes have a relatively large length, and the dispersing effect is poor in the formed polyurea coating, and it is difficult to form a conductive network. However, when shorter single-walled carbon nanotubes are used, the reinforcing structure formed in the coating is more uniform and compact, which is helpful to improve the mechanical properties of the coating, such as tensile strength and tear strength. At the same time, the shorter single-walled carbon nanotubes can form a more perfect conductive network in the coating, and as the length of the single-walled carbon nanotubes is increased, the conductive property of the formed coating will also be decreased.

[0169] It is 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 can be omitted, a plurality of steps can be combined into one step, and / or one step can be divided into a plurality of steps, etc.

[0170] The above description is merely preferred embodiments of the present application, but not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall fall within the protection scope of the present application.

Claims

1. A process for the preparation of MOFs based antistatic polyurea coating characterized in that, The method comprises the following steps: S100, mixing polyaspartic ester resin, dispersant, titanium white, defoaming agent and leveling agent, stirring and dispersing at 1000 rpm-2000 rpm for 5 min-10 min to obtain a first mixture; S200, adding single-walled carbon nanotubes and antistatic agent to the first mixture, stirring and dispersing at 3800 rpm-4600 rpm for 15 min-25 min; then adding MOFs material, stirring and dispersing at 3800 rpm-4600 rpm for 10 min-15 min; finally stirring and dispersing at 200 rpm-400 rpm for 5 min-10 min to obtain component A; S300, mixing component A and component B, stirring and dispersing at 3800 rpm-4600 rpm for 10 min-15 min to obtain MOFs-based antistatic polyurea coating; The single-walled carbon nanotubes, the antistatic agent and the MOFs material constitute a MOFs-based antistatic agent, and the components of the MOFs-based antistatic agent include 0.2-1 part of single-walled carbon nanotubes, 1.5-4 parts of antistatic agent and 0.05-0.3 parts of MOFs material according to mass fraction; The metal salt of the MOFs material is an acetylacetone metal salt, and the ligand is 2-methylimidazole; The antistatic agent is at least one of polyether antistatic agent, polyacrylate antistatic agent, sulfonic acid derivative antistatic agent and polyquaternary ammonium salt antistatic agent; The length of the single-walled carbon nanotubes is 5-20 µm, and the diameter is 1-1.8 nm; The component B includes an isocyanate curing agent.

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

3. The process for the preparation of MOFs based antistatic polyurea coating as claimed in claim 1, wherein, The preparation process of the MOFs material comprises the following steps: S1, mixing a metal salt and an organic ligand according to a molar ratio of 1:(2-3), stirring and then passing through a 50-100 mesh sieve to obtain a precursor powder; S2, uniformly 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 a MOFs raw material; S3, ball milling the MOFs raw material for 1-3 h, and then passing through a 100-200 mesh sieve to obtain a MOFs material.

4. The process for the preparation of MOFs based antistatic polyurea coatings according to claim 3, characterized in that, In step S2, the heating treatment comprises: A protective atmosphere is introduced into the tube furnace at a gas flow rate of 150-300 cc / min, and the tube furnace is heated at a heating rate of 2-4 ℃ / min to 100-120 ℃, and the gas inlet valve is closed; The tube furnace is pumped to a vacuum state, and then heated at a heating rate of 2-3 ℃ / min to 200-225 ℃, and held for 3-5 h; After the holding under vacuum is completed, the furnace is cooled to room temperature to obtain the MOFs raw material.

5. The process for the preparation of MOFs based antistatic polyurea coating according to claim 3, characterized in that, In step S3, the rotation speed is 150 rpm-250 rpm, the mass ratio of MOFs raw material to ball milling beads is 0.15-0.25, and the diameter of the ball milling beads is 0.3-10 mm.

6. The process for the preparation of MOFs based antistatic polyurea coating according to claim 1, characterized in that, The isocyanate curing agent is 4,4'-dicyclohexyl methane diisocyanate.

7. The process for the preparation of MOFs based antistatic polyurea coating according to any one of claims 1 to 5, characterized in that, The acetylacetone metal salt is zinc acetylacetone or cobalt acetylacetone.

8. The process for the preparation of MOFs based antistatic polyurea coating according to any one of claims 1 to 5, characterized in that, The dispersant is at least one of poly(methyl acrylate), poly(butyl acrylate), poly(ethyl acrylate) and cross-linked poly(acrylic acid); The leveling agent is a polyether-modified siloxane.

Images