Antistatic coating and preparation process thereof

Abstract

The invention discloses an antistatic coating and a preparation process thereof, and relates to the technical field of coatings. The antistatic coating is prepared from the following components: modified polyurethane emulsion, water-borne epoxy resin, water-borne acrylic resin, modified graphene oxide, a de-foaming agent and de-ionized water, the modified polyurethane emulsion contains a disulfide compound and dihydroxy quaternary ammonium salt; the modified graphene oxide is obtained by modifying cerium oxide and an amino coupling agent. According to the invention, the dihydroxy quaternary ammonium salt is prepared through amidation reaction and quaternization reaction in sequence, and the dihydroxy quaternary ammonium salt and the disulfide are used for modifying polyurethane together, so that the coating is endowed with antistatic and self-repairing properties; ce < 3 + > is loaded on the surface of the graphene oxide to form a more efficient conductive network, the antistatic performance of the coating is further improved, the amino coupling agent is connected with the cerium-loaded graphene oxide and the modified polyurethane to form a complex network structure, the dispersity of the cerium-loaded graphene oxide in the coating is improved, and agglomeration is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, in particular to an antistatic coating and a preparation process thereof. Background Art

[0002] Antistatic coating is a functional coating material applied on non-conductive materials. The conductive agents in the existing technology mainly include antistatic agents and conductive fillers. Conductive fillers such as carbon black, metal powder and conductive polymers have poor dispersion effects and are prone to agglomeration in the coating system, affecting the formation of the conductive network and reducing the antistatic durability. Antistatic agents are easily lost due to friction or cleaning, resulting in a decrease in antistatic performance.

[0003] CN201610622478.7 Graphene oxide-based water-based antistatic coating and its preparation method discloses a water-based antistatic coating with added coupling agent-modified graphene oxide microsheets. Although it can improve the phenomenon of easy agglomeration of graphene oxide, it may easily cause loss due to friction, resulting in performance degradation.

[0004] Therefore, we propose an antistatic coating and a preparation process thereof. Summary of the Invention

[0005] The purpose of the present invention is to provide an antistatic coating and a preparation process thereof to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solution: an antistatic coating, comprising the following components by mass: 35 to 45 parts of modified polyurethane emulsion, 15 to 25 parts of water-based epoxy resin, 10 to 30 parts of water-based acrylic resin, 1 to 5 parts of modified graphene oxide, 0.1 to 0.5 parts of defoaming agent, and 50 to 100 parts of deionized water; The modified polyurethane emulsion contains disulfide compounds and dihydroxy quaternary ammonium salts; The modified graphene oxide is obtained by modifying cerium oxide and an amino coupling agent.

[0007] Furthermore, the defoaming agent is one or a mixture of polyoxypropylene polyoxyethylene glyceryl ether and glyceryl stearate.

[0008] A preparation process of an antistatic coating comprises the following steps: The modified polyurethane emulsion, water-based epoxy resin, water-based acrylic resin, defoaming agent and deionized water are mixed and stirred evenly, and then the modified graphene oxide is added and stirred to obtain an antistatic coating.

[0009] Furthermore, the stirring speed is 1000 rpm to 2000 rpm.

[0010] Furthermore, the modified polyurethane emulsion is prepared by the following process: Step 1: Mix the polyol and the solvent, stir evenly, heat to react, then add isocyanate and dibutyltin dilaurate, stir and react for 2h~3h to obtain a polyurethane prepolymer; Step 2: mixing the disulfide compound, the dihydroxy quaternary ammonium salt and the solvent, adding the mixture to the polyurethane prepolymer while stirring, and heating the mixture for reaction to obtain a modified polyurethane; Step 3: Mix the modified polyurethane with deionized water, stir and emulsify for 1 h to 3 h to obtain a modified polyurethane emulsion.

[0011] Furthermore, in step 1, the mass ratio of polyol, solvent, isocyanate and dibutyltin dilaurate is (5-10): (1-3): (3-5): 0.01; In step 2, the mass ratio of the disulfide compound, the dihydroxy quaternary ammonium salt, the solvent and the polyurethane prepolymer is (1-3): (3-5): (4-6): 10.

[0012] Furthermore, in step 1 and step 2, the process conditions for the heating reaction are: temperature 60°C~80°C, time 1h~2h.

[0013] Furthermore, in step 3, the solid content of the modified polyurethane emulsion is 40%.

[0014] Furthermore, in step 1, the polyol is a mixture of one or more of polytetramethylene ether glycol, polycaprolactone polyol, and polyethylene adipate glycol; The isocyanate is a mixture of one or more of hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and tetramethylxylylene diisocyanate.

[0015] Furthermore, the solvent is a mixture of one or more of ethyl acetate, butyl acetate, acetone, toluene, and xylene.

[0016] Furthermore, in step 2, the disulfide compound is one or a mixture of 4,4'-dithiodiphenylamine and 4,4'-diaminodiphenyl disulfide.

[0017] Further, in step 2, the dihydroxy quaternary ammonium salt is prepared by the following process: S1: Mix N,N-dimethyl-1,3-propanediamine, phosphoric acid and ricinoleic acid, adjust the pH to 8.0-8.5, heat in an oil bath for reaction, and distill under reduced pressure to obtain product A; S2: Mix product A with isopropyl tone, stir evenly, add 1,3-dibromo-2,2-dimethoxypropane, heat in a water bath for reaction, distill under reduced pressure, and recrystallize to obtain a dihydroxy quaternary ammonium salt.

[0018] Furthermore, in S1, the mass ratio of N,N-dimethyl-1,3-propylenediamine and phosphoric acid is 10:(0.01~0.05).

[0019] Furthermore, the molar ratio of N,N-dimethyl-1,3-propylenediamine, ricinoleic acid and 1,3-dibromo-2,2-dimethoxypropane is (1-3): (1-3): (0.5-1.5).

[0020] Furthermore, in S2, the mass ratio of product A to isopropyl ketone is 1:(3~8).

[0021] Furthermore, in S1, the process conditions of the oil bath heating reaction are: temperature 135°C~145°C, time 10h~12h.

[0022] Furthermore, in S2, the process conditions of the water bath heating reaction are: temperature 70°C~90°C, time 20h~24h.

[0023] In the above technical solution, the amino group in N,N-dimethyl-1,3-propylenediamine is used to undergo an amidation reaction with the carboxyl group of ricinoleic acid, and then a quaternization reaction is carried out with 1,3-dibromo-2,2-dimethoxypropane to obtain a quaternary ammonium salt containing a dihydroxy group. The cation of the dihydroxy quaternary ammonium salt can be adsorbed on the polyurethane to form a conductive network, giving the polyurethane conductive properties. The hydroxyl group reacts with the isocyanate group in the polyurethane to form a covalent bond, anchoring the dihydroxy quaternary ammonium salt inside the coating, reducing the loss caused by friction or water washing, which causes the problem of decreased antistatic properties. In addition, the dihydroxy quaternary ammonium salt can also be used as a chain extender to adjust the hardness and flexibility of the coating formed after the coating is cured, as well as the bonding strength between the coating and the substrate. The addition of disulfide compounds introduces disulfide bonds, which endow polyurethane with the ability to reversibly break and reorganize, giving it self-repairing properties; disulfide bonds can also absorb ultraviolet energy, reduce the generation of free radicals, reduce the aging rate of the coating under ultraviolet radiation, and extend its service life.

[0024] Furthermore, the preparation method of the modified graphene oxide is as follows: Step A: Graphene oxide, water and ethanol are mixed and ultrasonically dispersed to obtain a graphene oxide dispersion, a cerium salt solution is added, stirred for 1 to 3 hours, allowed to stand for 20 to 24 hours, dialyzed, and freeze-dried to obtain cerium-loaded graphene oxide; Step B: mixing the cerium-loaded graphene oxide with N-N'-dimethylformamide, dispersing the mixture by ultrasonication, adding an amino coupling agent, heating the mixture in an oil bath for reaction, centrifuging, filtering, and freeze-drying the mixture to obtain modified graphene oxide.

[0025] Furthermore, in step A, the mass ratio of graphene oxide, water and ethanol is 1:(4-6):(2-4).

[0026] Furthermore, the volume ratio of the graphene oxide dispersion to the cerium salt solution is 1:(0.5~1).

[0027] Furthermore, in step B, the mass ratio of cerium-loaded graphene oxide, N-N'-dimethylformamide and amino coupling agent is 1: (10-15): (0.05-0.15).

[0028] Furthermore, the process conditions of ultrasonic dispersion are: ultrasonic frequency 60kHz~100kHz, time 0.5h~1.5hh.

[0029] Furthermore, the freeze-drying process conditions are: temperature -30°C to -40°C, time 20h to 30h.

[0030] Furthermore, in step B, the process conditions of the oil bath heating reaction are: temperature 120° C. to 130° C., time 12 h to 24 h.

[0031] Furthermore, in step B, the centrifugal process conditions are: rotation speed 3000r / min~6000r / min, time 5min~10min.

[0032] Furthermore, in step A, the cerium salt solution is prepared by mixing the cerium salt with deionized water, and the concentration is 3 mg / mL to 8 mg / mL.

[0033] Furthermore, the cerium salt is cerium nitrate or cerium chloride; The amino coupling agent is one or both of γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane.

[0034] In the above technical solution, Ce 3+ Loaded on the surface of graphene oxide, using Ce 3+ The redox properties of CeO promote the charge transfer between graphene oxide and the matrix, which is conducive to forming a more efficient conductive network and improving the antistatic performance of the coating; 3+ The empty orbitals can form coordination bonds with the carboxyl groups in graphene oxide, enhancing the interfacial bonding and improving the stability of the conductive network. In addition, cerium salt has a certain hygroscopicity, which can help graphene oxide maintain its conductivity in a humid environment. The cerium-loaded graphene oxide is then modified using an amino coupling agent. On the one hand, the cerium-loaded graphene oxide and modified polyurethane are connected by covalent bonds to form a complex network structure, reducing mobility and loss. On the other hand, the dispersion of the cerium-loaded graphene oxide in the coating is improved, agglomeration is reduced, and the conductive performance is further improved.

[0035] Compared with the prior art, the present invention has the following beneficial effects: 1. By preparing a dihydroxy quaternary ammonium salt, it is adsorbed on the polyurethane through cations to form a conductive network, giving the polyurethane conductive properties. The hydroxyl group reacts with the isocyanate group in the polyurethane to form a covalent bond, anchoring the dihydroxy quaternary ammonium salt inside the coating, reducing the loss caused by friction or water washing, which causes the problem of decreased antistatic properties. In addition, the dihydroxy quaternary ammonium salt can also be used as a chain extender to adjust the hardness and flexibility of the coating formed after the coating is cured, as well as the bonding strength between the coating and the substrate; Disulfide bonds are also introduced into polyurethane to give it the ability to reversibly break and reorganize, giving it self-repairing properties; disulfide bonds can also absorb ultraviolet energy, reduce the generation of free radicals, reduce the aging rate of the coating under ultraviolet radiation, and extend its service life.

[0036] 2. First, pass Ce 3+ Loaded on the surface of graphene oxide, using Ce 3+ The redox properties of graphene oxide promote the charge transfer between graphene oxide and the matrix, which is conducive to the formation of a more efficient conductive network. 3+ The empty orbitals can form coordination bonds with the carboxyl groups in graphene oxide, enhancing the interfacial bonding and improving the stability of the conductive network. The hygroscopicity of cerium salt helps graphene oxide maintain its conductivity in a humid environment, further improving the antistatic properties of the coating. The cerium-loaded graphene oxide is then modified using an amino coupling agent. On the one hand, the cerium-loaded graphene oxide and modified polyurethane are connected by covalent bonds to form a complex network structure, reducing mobility and loss. On the other hand, the dispersion of the cerium-loaded graphene oxide in the coating is improved, agglomeration is reduced, and the conductive properties of the coating are improved. DETAILED DESCRIPTION

[0037] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0038] In the following specific embodiments, Waterborne epoxy resin, EP137, was sourced from Shanghai Yantai E-Commerce Co., Ltd.; Water-based acrylic resin, model HY1330, from Shandong Haoyao New Materials Co., Ltd. The defoaming agent is polyoxypropylene polyoxyethylene glycerol ether, model GPE-3000; The polyol is polytetramethylene ether glycol with a molecular weight of 2000; Isocyanate is isophorone diisocyanate, sourced from Shanghai Hongzhuang Chemical Technology Co., Ltd. The solvent was acetone, which was sourced from Nanjing Runsheng Petrochemical Co., Ltd. The disulfide compound was 4,4'-diphenyldisulfide, which was obtained from Wuhan Linsheng Technology Co., Ltd.; Graphene oxide, 3 μm in diameter; The cerium salt solution is a cerium nitrate solution, and the preparation method is as follows: cerium nitrate and deionized water are mixed in a ratio of (3-8) mg:1 mL, and stirred evenly to obtain a cerium nitrate solution; Cerium nitrate, sourced from Zhiheng Zhiyuan Chemical; The amino coupling agent was γ-aminopropyltrimethoxysilane, which was obtained from Yunsheng Chemical (Shandong) Co., Ltd. Waterborne polyurethane, solid content 40%, sourced from Anhui Feimiao Chemical Co., Ltd.; Example 1: A process for preparing an antistatic coating, comprising the following steps: (1) Preparation of modified polyurethane emulsion: S1: N,N-dimethyl-1,3-propylenediamine, phosphoric acid and ricinoleic acid were mixed, the pH was adjusted to 8.5, the mixture was heated in an oil bath for reaction, and vacuum distillation was performed to obtain product A; S2: Product A was mixed with isopropyl ketone in a mass ratio of 1:3, stirred evenly, 1,3-dibromo-2,2-dimethoxypropane was added, the mixture was heated in a water bath for reaction, vacuum distillation was performed, and recrystallization was performed to obtain a dihydroxy quaternary ammonium salt; in S1, the mass ratio of N,N-dimethyl-1,3-propylenediamine and phosphoric acid was 10:0.05; the molar ratio of N,N-dimethyl-1,3-propylenediamine, ricinoleic acid and 1,3-dibromo-2,2-dimethoxypropane was 3:3:1.5; in S1, the process conditions for the oil bath heating reaction were: temperature 145°C, time 12 h; in S2, the process conditions for the water bath heating reaction were: temperature 90°C, time 24 h; Step 1: Mix polytetramethylenediol and acetone, stir evenly, heat to react, then add isophorone diisocyanate and dibutyltin dilaurate, stir and react for 3 hours to obtain a polyurethane prepolymer; Step 2: Mix 4,4'-dithiodiphenylamine, dihydroxy quaternary ammonium salt and acetone, add them to the polyurethane prepolymer while stirring, heat and react to obtain a modified polyurethane; Step 3: Mix the modified polyurethane with deionized water, stir and emulsify for 3 hours to obtain a modified polyurethane emulsion; in step 1, the mass ratio of polytetramethylenediol, acetone, isophorone diisocyanate and dibutyltin dilaurate is 10:3:5:0.01; in step 2, the mass ratio of 4,4'-dithiodiphenylamine, dihydroxy quaternary ammonium salt, acetone and polyurethane prepolymer is 3:5:6:10; the process conditions of the heating reaction are: temperature 80°C, time 2 hours; in step 3, the solid content of the modified polyurethane emulsion is 40%; (2) Preparation of modified graphene: Step A: Graphene oxide, water and ethanol were mixed in a mass ratio of 1:6:4, ultrasonically dispersed to obtain a graphene oxide dispersion, 8 mg / mL cerium nitrate solution was added, stirred for 3 h, allowed to stand for 24 h, dialyzed, and freeze-dried to obtain cerium-loaded graphene oxide; Step B: Cerium-loaded graphene oxide was mixed with N-N'-dimethylformamide, ultrasonically dispersed, γ-aminopropyltrimethoxysilane was added, heated in an oil bath for reaction, centrifuged, filtered, and freeze-dried to obtain modified graphene oxide; Graphene oxide dispersion was mixed with cerium nitrate solution ... modified graphene oxide. The volume ratio of the solution is 1:1; in step B, the mass ratio of cerium-loaded graphene oxide, N-N'-dimethylformamide, and γ-aminopropyltrimethoxysilane is 1:10:0.15; the process conditions for ultrasonic dispersion are: ultrasonic frequency 100 kHz, time 1.5; the process conditions for freeze-drying are: temperature -30°C, time 30 hours; in step B, the process conditions for oil bath heating reaction are: temperature 130°C, time 24 hours; in step B, the process conditions for centrifugation are: speed 6000 r / min, time 10 minutes; (3) Preparation of antistatic coating: The modified polyurethane emulsion, water-based epoxy resin, water-based acrylic resin, polyoxypropylene polyoxyethylene glycerol ether and deionized water are mixed and stirred evenly, and then modified graphene oxide is added, and the mixture is stirred at a speed of 2000 rpm to obtain an antistatic coating; the antistatic coating includes the following components by mass: 45 parts of modified polyurethane emulsion, 25 parts of water-based epoxy resin, 30 parts of water-based acrylic resin, 5 parts of modified graphene oxide, 0.5 parts of polyoxypropylene polyoxyethylene glycerol ether, and 100 parts of deionized water.

[0039] Example 2: A process for preparing an antistatic coating, comprising the following steps: (1) Preparation of modified polyurethane emulsion: S1: N,N-dimethyl-1,3-propylenediamine, phosphoric acid and ricinoleic acid were mixed, the pH was adjusted to 8.3, the mixture was heated in an oil bath for reaction, and vacuum distillation was performed to obtain product A; S2: Product A was mixed with isopropyl ketone in a mass ratio of 1:5, stirred evenly, 1,3-dibromo-2,2-dimethoxypropane was added, the mixture was heated in a water bath for reaction, vacuum distillation was performed, and recrystallization was performed to obtain a dihydroxy quaternary ammonium salt; in S1, the mass ratio of N,N-dimethyl-1,3-propylenediamine and phosphoric acid was 10:0.03; the molar ratio of N,N-dimethyl-1,3-propylenediamine, ricinoleic acid and 1,3-dibromo-2,2-dimethoxypropane was 2:2:1.0; in S1, the process conditions for the oil bath heating reaction were: temperature 140°C, time 11 h; in S2, the process conditions for the water bath heating reaction were: temperature 80°C, time 22 h; Step 1: Mix polytetramethylene glycol with acetone, stir evenly, heat to react, then add isophorone diisocyanate and dibutyltin dilaurate, stir and react for 2.5 hours to obtain a polyurethane prepolymer; Step 2: Mix 4,4'-dithiodiphenylamine, dihydroxy quaternary ammonium salt and acetone, add them to the polyurethane prepolymer while stirring, heat and react to obtain a modified polyurethane; Step 3: Mix the modified polyurethane with deionized water, stir and emulsify for 2 hours to obtain to a modified polyurethane emulsion; in step 1, the mass ratio of polytetramethylene glycol, acetone, isophorone diisocyanate and dibutyltin dilaurate is 8:2:4:0.01; in step 2, the mass ratio of 4,4'-dithiodiphenylamine, dihydroxy quaternary ammonium salt, acetone and polyurethane prepolymer is 2:4:5:10; the process conditions of the heating reaction are: temperature 70°C, time 1.5h; in step 3, the solid content of the modified polyurethane emulsion is 40%; (2) Preparation of modified graphene: Step A: Graphene oxide, water and ethanol were mixed in a mass ratio of 1:5:3, ultrasonically dispersed to obtain a graphene oxide dispersion, added with a cerium nitrate solution having a concentration of 5 mg / mL, stirred for 2 h, allowed to stand for 22 h, dialyzed, and freeze-dried to obtain cerium-loaded graphene oxide; Step B: Cerium-loaded graphene oxide was mixed with N-N'-dimethylformamide, ultrasonically dispersed, γ-aminopropyltrimethoxysilane was added, heated in an oil bath for reaction, centrifuged, filtered, and freeze-dried to obtain modified graphene oxide; The graphene oxide dispersion was mixed with the cerium nitrate solution. The volume ratio of the liquid is 1:0.8; in step B, the mass ratio of cerium-loaded graphene oxide, N-N'-dimethylformamide and γ-aminopropyltrimethoxysilane is 1:12:0.10; the process conditions for ultrasonic dispersion are: ultrasonic frequency 80 kHz, time 1.0 h; the process conditions for freeze-drying are: temperature -35°C, time 25 h; in step B, the process conditions for oil bath heating reaction are: temperature 125°C, time 18 h; in step B, the process conditions for centrifugation are: speed 4500 r / min, time 7 min; (3) Preparation of antistatic coating: The modified polyurethane emulsion, water-based epoxy resin, water-based acrylic resin, polyoxypropylene polyoxyethylene glycerol ether and deionized water are mixed and stirred evenly, and then modified graphene oxide is added and stirred at a speed of 1500 rpm to obtain an antistatic coating; the antistatic coating includes the following components by mass: 40 parts of modified polyurethane emulsion, 20 parts of water-based epoxy resin, 20 parts of water-based acrylic resin, 3 parts of modified graphene oxide, 0.3 parts of polyoxypropylene polyoxyethylene glycerol ether and 75 parts of deionized water.

[0040] Example 3: A process for preparing an antistatic coating, comprising the following steps: (1) Preparation of modified polyurethane emulsion: S1: N,N-dimethyl-1,3-propylenediamine, phosphoric acid and ricinoleic acid were mixed, the pH was adjusted to 8.0, the mixture was heated in an oil bath for reaction, and vacuum distillation was performed to obtain product A; S2: Product A was mixed with isopropyl ketone in a mass ratio of 1:8, stirred evenly, 1,3-dibromo-2,2-dimethoxypropane was added, the mixture was heated in a water bath for reaction, vacuum distillation was performed, and recrystallization was performed to obtain a dihydroxy quaternary ammonium salt; in S1, the mass ratio of N,N-dimethyl-1,3-propylenediamine and phosphoric acid was 10:0.01; the molar ratio of N,N-dimethyl-1,3-propylenediamine, ricinoleic acid and 1,3-dibromo-2,2-dimethoxypropane was 1:1:0.5; in S1, the process conditions for the oil bath heating reaction were: temperature 135°C, time 10 h; in S2, the process conditions for the water bath heating reaction were: temperature 70°C, time 20 h; Step 1: Mix polytetramethylene glycol and acetone, stir evenly, heat to react, then add isophorone diisocyanate and dibutyltin dilaurate, stir and react for 2 hours to obtain a polyurethane prepolymer; Step 2: Mix 4,4'-dithiodiphenylamine, dihydroxy quaternary ammonium salt and acetone, add them to the polyurethane prepolymer while stirring, heat and react to obtain a modified polyurethane; Step 3: Mix the modified polyurethane with deionized water, stir and emulsify for 1 hour to obtain a modified polyurethane emulsion; in step 1, the mass ratio of polytetramethylene glycol, acetone, isophorone diisocyanate and dibutyltin dilaurate is 5:1:3:0.01; in step 2, the mass ratio of 4,4'-dithiodiphenylamine, dihydroxy quaternary ammonium salt, acetone and polyurethane prepolymer is 1:3:4:10; the process conditions of the heating reaction are: temperature 60°C, time 1 hour; in step 3, the solid content of the modified polyurethane emulsion is 40%; (2) Preparation of modified graphene: Step A: Graphene oxide, water and ethanol were mixed in a mass ratio of 1:6:4, ultrasonically dispersed to obtain a graphene oxide dispersion, 3 mg / mL cerium nitrate solution was added, stirred for 3 h, allowed to stand for 24 h, dialyzed, and freeze-dried to obtain cerium-loaded graphene oxide; Step B: Cerium-loaded graphene oxide was mixed with N-N'-dimethylformamide, ultrasonically dispersed, γ-aminopropyltrimethoxysilane was added, heated in an oil bath for reaction, centrifuged, filtered, and freeze-dried to obtain modified graphene oxide; The graphene oxide dispersion was mixed with cerium nitrate solution. The volume ratio of the liquid is 1:0.5; in step B, the mass ratio of cerium-loaded graphene oxide, N-N'-dimethylformamide and γ-aminopropyltrimethoxysilane is 1:15:0.05; the process conditions of ultrasonic dispersion are: ultrasonic frequency 60 kHz, time 0.5 h; the process conditions of freeze drying are: temperature -40 ° C, time 20 h; in step B, the process conditions of oil bath heating reaction are: temperature 120 ° C, time 12 h; in step B, the process conditions of centrifugation are: speed 3000 r / min, time 5 min; (3) Preparation of antistatic coating: The modified polyurethane emulsion, water-based epoxy resin, water-based acrylic resin, polyoxypropylene polyoxyethylene glycerol ether and deionized water are mixed and stirred evenly, and then modified graphene oxide is added and stirred at a speed of 1000 rpm to obtain an antistatic coating; the antistatic coating includes the following components by mass: 35 parts of modified polyurethane emulsion, 15 parts of water-based epoxy resin, 10 parts of water-based acrylic resin, 1 part of modified graphene oxide, 0.1 part of polyoxypropylene polyoxyethylene glycerol ether, and 50 parts of deionized water.

[0041] Comparative Example 1: Using Example 1 as a comparison, the graphene oxide is not modified, and the other conditions remain unchanged. An antistatic coating includes the following components by mass: 45 parts of modified polyurethane emulsion, 25 parts of water-based epoxy resin, 30 parts of water-based acrylic resin, 5 parts of graphene oxide, 0.5 parts of polyoxypropylene polyoxyethylene glycerol ether, and 100 parts of deionized water.

[0042] Comparative Example 2: Using Example 1 as a comparison, instead of using modified polyurethane emulsion, commercially available water-based polyurethane is used, and other conditions remain unchanged. An antistatic coating includes the following components by mass: 45 parts of water-based polyurethane, 25 parts of water-based epoxy resin, 30 parts of water-based acrylic resin, 5 parts of modified graphene oxide, 0.5 parts of polyoxypropylene polyoxyethylene glycerol ether, and 100 parts of deionized water.

[0043] Comparative Example 3: Using Example 1 as a comparison, the graphene oxide is not modified, and the modified polyurethane emulsion is not used. The other conditions remain unchanged. An antistatic coating includes the following components by mass: 45 parts of water-based polyurethane, 25 parts of water-based epoxy resin, 30 parts of water-based acrylic resin, 5 parts of graphene oxide, 0.5 parts of polyoxypropylene polyoxyethylene glycerol ether, and 100 parts of deionized water.

[0044] experiment: Surface resistance test: Take the antistatic coating obtained in the examples and comparative examples and use a high resistance meter MCP-HT450 at 25°C and a relative humidity of 60% to test the surface resistance. Adhesion and wear resistance test: The antistatic coatings obtained in the examples and comparative examples were evenly coated on a substrate with a coating thickness of 0.5 mm. Adhesion and wear resistance tests were performed according to GBT 22374-2008. During the wear test, the load applied to the specimen was 750 g and the number of frictions was 500 times; The following table shows the performance test results of the obtained antistatic coating;

[0045] Based on the data in the above table, we can draw the following conclusions: In contrast to Example 1, the surface resistivity of the graphene oxide was improved without modification of the graphene oxide in Example 1, indicating that the antistatic performance was reduced because Ce 3+ Loading on the surface of graphene oxide can promote the charge transfer between graphene oxide and the matrix, which is conducive to the formation of a more efficient conductive network. 3+ The empty orbitals can form coordination bonds with the carboxyl groups in graphene oxide, enhancing the interfacial bonding force and improving the stability of the conductive network. Then, the amino coupling agent is used for modification. On the one hand, the cerium-loaded graphene oxide and the modified polyurethane are connected by covalent bonds to form a complex network structure, which reduces the mobility and loss. On the other hand, the dispersion of the cerium-loaded graphene oxide in the coating is improved, the agglomeration is reduced, and the conductive performance is further improved. In contrast to Example 1, Comparative Example 2 does not use a modified polyurethane emulsion, and the antistatic performance decreases, the adhesion grade decreases, and the wear quality increases, indicating that the wear resistance of the coating decreases. This is because the cations of the prepared dihydroxy quaternary ammonium salt can be adsorbed on the polyurethane to form a conductive network, giving the polyurethane conductive properties. The dihydroxy quaternary ammonium salt can also be used as a chain extender to adjust the hardness, flexibility, and bonding strength between the coating and the substrate formed after the coating is cured. The introduction of disulfide bonds gives the polyurethane reversible fracture and recombination capabilities, so that it has self-repairing properties and enhances wear resistance. In contrast to Example 1, in Comparative Example 3, graphene oxide was not modified and modified polyurethane emulsion was not used, and all properties were reduced. In summary, it can be explained that the setting of the materials and process parameters used in this application can promote the improvement of the antistatic performance, wear resistance and adhesion of the obtained antistatic coating.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. An antistatic coating, characterized in that: The invention comprises the following components by weight: 35 to 45 parts of modified polyurethane emulsion, 15 to 25 parts of waterborne epoxy resin, 10 to 30 parts of waterborne acrylic resin, 1 to 5 parts of modified graphene oxide, 0.1 to 0.5 parts of defoaming agent, and 50 to 100 parts of deionized water; The modified polyurethane emulsion contains disulfide compounds and dihydroxy quaternary ammonium salts; The modified graphene oxide is obtained by modifying cerium oxide and a coupling agent.

2. A preparation process for an antistatic coating, characterized in that: The following steps are involved: The modified polyurethane emulsion, water-based epoxy resin, water-based acrylic resin, defoamer and deionized water are mixed and stirred evenly, and then the modified graphene oxide is added and stirred to obtain an antistatic coating; The modified polyurethane emulsion is prepared by the following steps: Step 1: Mix the polyol and the solvent, stir evenly, heat to react, then add isocyanate and dibutyltin dilaurate, stir and react for 2h~3h to obtain a polyurethane prepolymer; Step 2: mixing the disulfide compound, the dihydroxy quaternary ammonium salt and the solvent, adding the mixture to the polyurethane prepolymer while stirring, and heating the mixture for reaction to obtain a modified polyurethane; Step 3: Mix the modified polyurethane with deionized water, stir and emulsify for 1 h to 3 h to obtain a modified polyurethane emulsion.

3. The process for preparing an antistatic coating according to claim 2, wherein: In step 2, the dihydroxy quaternary ammonium salt is prepared by the following process: S1: Mix N,N-dimethyl-1,3-propanediamine, phosphoric acid and ricinoleic acid, adjust the pH to 8.0-8.5, heat in an oil bath for reaction, and distill under reduced pressure to obtain product A; S2: Mix product A with isopropyl tone, stir evenly, add 1,3-dibromo-2,2-dimethoxypropane, heat in a water bath for reaction, distill under reduced pressure, and recrystallize to obtain a dihydroxy quaternary ammonium salt.

4. The process for preparing an antistatic coating according to claim 2, wherein: The preparation method of the modified graphene oxide is as follows: Step A: Graphene oxide, water and ethanol are mixed and ultrasonically dispersed to obtain a graphene oxide dispersion, a cerium salt solution is added, stirred for 1 to 3 hours, allowed to stand for 20 to 24 hours, dialyzed, and freeze-dried to obtain cerium-loaded graphene oxide; Step B: mixing the cerium-loaded graphene oxide with N-N'-dimethylformamide, dispersing the mixture by ultrasonication, adding an amino coupling agent, heating the mixture in an oil bath for reaction, centrifuging, filtering, and freeze-drying the mixture to obtain modified graphene oxide.

5. The process for preparing an antistatic coating according to claim 2, wherein: In step 1, the mass ratio of polyol, solvent, isocyanate and dibutyltin dilaurate is (5-10): (1-3): (3-5): 0.01; In step 2, the mass ratio of the disulfide compound, the dihydroxy quaternary ammonium salt, the solvent and the polyurethane prepolymer is (1-3): (3-5): (4-6):

10.

6. The process for preparing an antistatic coating according to claim 3, wherein: In S1, the mass ratio of N,N-dimethyl-1,3-propylenediamine and phosphoric acid is 10:(0.01~0.05); The molar ratio of N,N-dimethyl-1,3-propylenediamine, ricinoleic acid and 1,3-dibromo-2,2-dimethoxypropane is (1~3):(1~3):(0.5~1.5).

7. The process for preparing an antistatic coating according to claim 4, wherein: In step A, the mass ratio of graphene oxide, water and ethanol is 1:(4-6):(2-4); In step B, the mass ratio of cerium-supported graphene oxide, N-N'-dimethylformamide, and amino coupling agent is 1:(10-15):(0.05-0.15); The volume ratio of graphene oxide dispersion to cerium salt solution is 1:(0.5~1).

8. The process for preparing an antistatic coating according to claim 4, wherein: The cerium salt solution is prepared by mixing cerium salt with deionized water, and the concentration is 3 mg / mL to 8 mg / mL; The cerium salt is cerium nitrate or cerium chloride.

9. The process for preparing an antistatic coating according to claim 2, wherein: The polyol is a mixture of one or more of polytetramethylene ether glycol, polycaprolactone polyol, and polyethylene adipate glycol; The isocyanate is a mixture of one or more of hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and tetramethylxylylene diisocyanate.

10. The process for preparing an antistatic coating according to claim 2, wherein: The disulfide compound is one of 4,4'-dithiodiphenylamine and 4,4'-diaminodiphenyl disulfide, or a mixture of the two.

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