Antistatic coating containing single-walled carbon nanotubes and preparation method thereof

Abstract

The invention relates to the technical field of antistatic coatings, in particular to an antistatic coating containing single-walled carbon nanotubes and a preparation method of the antistatic coating. The method specifically comprises the following steps: step 1, sequentially carrying out acidizing treatment and acylating chlorination treatment on a single-walled carbon nanotube to obtain an acylating chlorination carbon nanotube; step two, (1) initiating polymerization of 1-allyl benzotriazole, N-tert-butylallyl-1-amine and allyl polyglycol ether, so as to obtain a product A; (2) carrying out substitution reaction on the product A and bromomethyl ether to obtain a product B; (3) carrying out a click reaction on the product B and 4, 6-dihydroxy-2-mercaptopyrimidine to obtain a modifier; step 3, performing modification treatment on the acylating chlorination carbon nano tube by using a modifier to obtain a modified carbon nano tube; step 4, uniformly mixing waterborne polyurethane, the modified carbon nanotubes, a curing agent, a coalescing agent, a tackifier, a defoaming agent, a flatting agent and deionized water to obtain the antistatic coating.

Description

Technical Field

[0001] The invention relates to the technical field of antistatic coatings, in particular to an antistatic coating containing single-walled carbon nanotubes and a preparation method thereof. Background Art

[0002] Waterborne polyurethane has the properties of wear resistance, oil resistance, corrosion resistance, compatibility and easy modification, and is widely used in medical equipment, aerospace and other fields. However, since resin materials usually have electrical insulation and extremely high resistivity, polyurethane materials are very likely to cause electrostatic discharge (ESD), destroying the electronic equipment in contact, thereby causing electrostatic discharge hazards, and even causing fires and explosions. This undoubtedly severely limits its application in related fields.

[0003] Carbon nanotubes (CNT), especially single-walled carbon nanotubes (SW-CNT), have special structures and excellent mechanical, optical and electrical properties. Therefore, many researchers use them as conductive materials to prepare antistatic coatings in antistatic applications. However, single-walled carbon nanotubes have fewer active groups, so they interact very weakly with the polymer materials in the resin glue, and usually agglomerate in the resin glue. In order to obtain excellent antistatic properties, carbon nanotubes must be evenly dispersed in the resin glue.

[0004] In summary, the present invention modifies single-walled carbon nanotubes to improve their dispersibility in polyurethane, thereby achieving modification and enhancement of the polyurethane glue to obtain a coating with excellent antistatic properties, which can enhance the application range of polyurethane coatings and has obvious practical significance. Summary of the invention

[0005] The object of the present invention is to provide an antistatic coating containing single-walled carbon nanotubes and a preparation method thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions: An antistatic coating containing single-walled carbon nanotubes comprises the following components: by weight, 40-50 parts of waterborne polyurethane, 1-6 parts of modified carbon nanotubes, 2-5 parts of curing agent, 1-3 parts of film-forming aid, 0.1-0.5 parts of tackifier, 0.1-0.5 parts of defoamer, 0.1-1 parts of leveling agent and 10-20 parts of deionized water.

[0007] Furthermore, the preparation method of the antistatic coating comprises the following steps: Step 1: single-walled carbon nanotubes are subjected to acidification treatment and acyl chloride treatment in sequence to obtain acyl chloride carbon nanotubes; Step 2: (1) 1-allylbenzotriazole, N-tert-butylpropenyl-1-amine and allyl polyethylene glycol ether initiate polymerization to obtain product A; (2) product A undergoes substitution reaction with bromomethyl ether to obtain product B; (3) product B undergoes click reaction with 4,6-dihydroxy-2-mercaptopyrimidine to obtain a modifier; Step 3: modifying the acyl chloride carbon nanotubes with a modifying agent to obtain modified carbon nanotubes; Step 4: Evenly mix the waterborne polyurethane, modified carbon nanotubes, curing agent, film-forming aid, tackifier, defoamer, leveling agent and deionized water to obtain an antistatic coating.

[0008] Furthermore, the preparation method of the chlorinated carbon nanotubes is as follows: (1) adding single-walled carbon nanotubes, concentrated sulfuric acid and concentrated nitric acid into a reaction container, stirring and mixing them evenly, then heating to 50-100°C, soaking them for 1-12 hours, filtering, washing with deionized water until neutral, and drying to obtain acidified carbon nanotubes; (2) adding the acidified carbon nanotubes and dithionyl chloride into a reaction container, stirring and mixing them evenly at room temperature, then heating to 50-70°C, continuing stirring for 1-24 hours, stopping stirring, and finally removing excess dithionyl chloride by rotary evaporation to obtain chlorinated carbon nanotubes.

[0009] Furthermore, the ratio of the single-walled carbon nanotubes, concentrated sulfuric acid and concentrated nitric acid is (1-2) g:30 mL:10 mL; wherein the concentration of the concentrated sulfuric acid is ≥96%, and the concentration of the concentrated nitric acid is ≥68%.

[0010] Furthermore, the ratio of the acidified carbon nanotubes to the dichlorothionyl is (1-5) g:100 mL.

[0011] Furthermore, the preparation method of the modifier is as follows: (1) adding 1-allylbenzotriazole, N-tert-butylpropenyl-1-amine, allyl polyethylene glycol ether and deionized water into a reaction container, introducing nitrogen, and stirring for 1-2 hours to obtain a reaction solution; (2) maintaining stirring, heating the reaction solution to 50-80° C., and then uniformly adding an initiator to the reaction solution within 0.5-2 hours. After the addition is completed, continuing the reaction for 0.5-2 hours, terminating the reaction, and removing the deionized water by vacuum distillation to obtain a product A; (3) adding the product A and methyl bromide to anhydrous ethanol. , reflux reaction at 70-85°C for 6-24h, terminate the reaction, remove anhydrous ethanol and excess bromomethyl ether by vacuum distillation, add sodium hydroxide aqueous solution, adjust the solution pH to 6.8-7.2, and finally separate and dry to obtain product B; (4) add product B, 4,6-dihydroxy-2-mercaptopyrimidine, photoinitiator and anhydrous ethanol into a reaction vessel, stir and mix evenly, and irradiate under ultraviolet light at 350-370nm for 1-20min to terminate the reaction, and finally remove anhydrous ethanol by vacuum distillation to obtain a modifier.

[0012] Furthermore, the mass ratio of the 1-allylbenzotriazole, N-tert-butylpropenyl-1-amine, allyl polyethylene glycol ether and initiator is (1-2):(1-2):3:(0.15-0.3).

[0013] Furthermore, the mass ratio of the product A to methyl bromide is 5:2.

[0014] Furthermore, the mass ratio of the product B, 4,6-dihydroxy-2-mercaptopyrimidine and the photoinitiator is 5:(1~2):(0.15~0.3).

[0015] Furthermore, the preparation method of the modified carbon nanotubes is: adding acyl chloride carbon nanotubes, a modifier and ethyl acetate into a reaction container, reflux reacting at 70-90° C. for 24-72 hours, and finally filtering, washing and drying to obtain the modified carbon nanotubes.

[0016] Furthermore, the mass ratio of the acyl chloride carbon nanotubes to the modifier is 1:(0.1-0.5).

[0017] Furthermore, the preparation method of the antistatic coating is as follows: (1) adding waterborne polyurethane, modified carbon nanotubes, film-forming aid, tackifier, defoamer, leveling agent and deionized water into a reaction container, and stirring and mixing for 1 to 3 hours; (2) adding a curing agent to (1), stirring and mixing for 0.5 to 1 hour, and obtaining the antistatic coating.

[0018] Furthermore, the film-forming aid includes but is not limited to any one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether and ethylene glycol.

[0019] Furthermore, the viscosity enhancer is a cellulose thickener.

[0020] Furthermore, the curing agent is an amine curing agent.

[0021] The scheme is designed to enhance the antistatic performance of waterborne polyurethane coatings by introducing single-walled carbon nanotubes, but single-walled carbon nanotubes usually show agglomeration in resin solutions. If single-walled carbon nanotubes are directly added to waterborne polyurethane, the modification of waterborne polyurethane cannot be truly and effectively achieved. Therefore, the present invention is designed to modify the single-walled carbon nanotubes so that their dispersion performance in waterborne polyurethane is enhanced, and at the same time, some other relevant important properties of waterborne polyurethane coatings can be improved as much as possible, thereby improving the anti-aging properties, adhesion strength, etc. of the coating obtained by coating.

[0022] In the present invention, 1-allylbenzotriazole, N-tert-butylpropenyl-1-amine and allyl polyethylene glycol ether are initiated to polymerize to prepare product A; wherein N-tert-butylpropenyl-1-amine introduces a secondary amine structure (-NH-) into product A, which can then undergo a substitution reaction with -Br in bromomethyl ether to prepare product B; finally, 4,6-dihydroxy-2-mercaptopyrimidine is added to prepare a modifier through a click reaction; finally, the treated single-walled carbon nanotubes (acyl chloride carbon nanotubes) are modified by the modifier to obtain modified carbon nanotubes with a quaternary ammonium salt structure. The quaternary ammonium salt structure on the modified carbon nanotubes can further enhance the antistatic property of the waterborne polyurethane coating; in addition, the modified carbon nanotubes also contain benzotriazole structure, a large number of ether bonds and hydroxyl groups. The benzotriazole structure can improve the anti-ultraviolet oxidation performance of the waterborne polyurethane coating, so that the cured waterborne polyurethane coating can maintain stable performance for a long time and improve its application life (anti-aging performance is enhanced). In addition, the benzotriazole structure also has dispersing and antistatic effects; the abundant ether bonds can cooperate with the quaternary ammonium salt structure and the benzotriazole structure to further enhance the antistatic property of the waterborne polyurethane coating, and at the same time, it can also cooperate with the hydroxyl and benzotriazole structures to enhance the dispersibility of the modified carbon nanotubes in the waterborne polyurethane, and also make the modified carbon nanotubes and the waterborne polyurethane more closely connected, which plays a certain role in the adhesion firmness of the coating.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention solves the defects of poor dispersibility and easy agglomeration of single-walled carbon nanotubes in waterborne polyurethane coatings by modifying single-walled carbon nanotubes, so that the coating exhibits excellent antistatic properties; 2. Since the benzotriazole structure introduced into the single-walled carbon nanotubes has anti-ultraviolet oxidation effect, it improves the anti-ultraviolet oxidation performance of waterborne polyurethane coatings, enhances the anti-aging performance of the coating to a certain extent, and increases its application life; 3. As the dispersibility of single-walled carbon nanotubes is improved and the modified carbon nanotubes are more closely connected with waterborne polyurethane, the strength of the coating obtained by final coating and curing and its connection with the substrate are also significantly improved. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that the purchase manufacturers of all the raw materials involved in the present invention are not subject to any special restrictions, and exemplary examples include: single-walled carbon nanotube model SWCNT-005, purity 99.99%, item number: AM-C6-067-1, tube diameter 5nm, purchased from Yamei Nano Technology Co., Ltd.; 1-allylbenzotriazole purity 98%, CAS number: 52298-91-6, methyl bromide purity 98%, all purchased from JACS-Zhengzhou Jacks Chemical Products Co., Ltd.; N-tert-butylpropenyl-1-amine purity 98%, CAS number: 16386-68-3, curing agent is ethyl Diamine, CAS number: 6780-13-8, all purchased from Shanghai Dingmiao Chemical Technology Co., Ltd.; allyl polyethylene glycol ether purity 95%, item number: 1371135, CAS number: 56641-05-5, purchased from Beijing Tianyi Yongchang Chemical Technology Co., Ltd.; 4,6-dihydroxy-2-mercaptopyrimidine purity 98%, CAS number: 956086-95-6, purchased from Ester (Chengdu) Biopharmaceutical Co., Ltd.; waterborne polyurethane model DB3520, solid content 35±2%, purchased from Wuhan Double Bond Chem Sealing Materials Co., Ltd.; photoinitiator model IHT-PI EMK, purity 99%, and thickener carboxymethyl cellulose, purity 99%, were purchased from Hubei Yongkuo Technology Co., Ltd.; ethylene glycol monomethyl ether, purity 99%, was purchased from Shanghai Jinjinle Industrial Co., Ltd.; defoamer model DE-H055 was purchased from Yueguan New Materials Co., Ltd.; leveling agent model PU-202 was purchased from Lugong Auxiliary Agent Company; the following parts are by weight, 10g each.

[0026] Example 1: A method for preparing an antistatic coating containing single-walled carbon nanotubes: Step 1: Preparation of chlorinated carbon nanotubes: (1) Add 10 parts of single-walled carbon nanotubes, 2 L of 98 wt% concentrated sulfuric acid and 0.667 L of 68 wt% concentrated nitric acid into a reaction container, stir and mix evenly, then heat to 80°C, soak for 6 hours, and finally filter, wash and dry to obtain acidified carbon nanotubes; (2) Add 8 parts of acidified carbon nanotubes and 2 L of dithionyl chloride into a reaction container, stir and mix evenly at room temperature, then heat to 55°C, continue stirring for 12 hours, stop stirring, and finally remove excess dithionyl chloride by rotary evaporation to obtain chlorinated carbon nanotubes; Step 2: Preparation of modifier: (1) Add 1.5 parts of 1-allylbenzotriazole, 1.5 parts of N-tert-butylpropenyl-1-amine, 3 parts of allyl polyethylene glycol ether and 10 parts of deionized water into a reaction container, introduce nitrogen, and stir for 2 hours to obtain a reaction solution; (2) Keep stirring and heat the reaction solution to 70°C, then uniformly add a 10 wt% aqueous solution of ammonium persulfate (prepared by adding 0.22 parts of ammonium persulfate to deionized water) to the reaction solution within 2 hours. After the addition is complete, continue the reaction for 2 hours, terminate the reaction, and finally remove the deionized water by vacuum distillation to obtain product A; (3) Mix 4 parts of product A and 1. 6 parts of methyl bromide are added to 15 parts of anhydrous ethanol, and the mixture is refluxed at 80°C for 18 hours to terminate the reaction. The anhydrous ethanol and excess methyl bromide are removed by vacuum distillation, and a 10 wt % sodium hydroxide aqueous solution is added thereto to adjust the pH value of the solution to 7.0. The mixture is separated and dried to obtain product B. (4) 4 parts of product B, 1.2 parts of 4,6-dihydroxy-2-mercaptopyrimidine, 0.2 parts of a photoinitiator and 10 parts of anhydrous ethanol are added to a reaction container, stirred and mixed evenly, and irradiated under ultraviolet light at 350 nm for 10 minutes to terminate the reaction. The anhydrous ethanol is removed by vacuum distillation to obtain a modifier. Step 3: Preparation of modified carbon nanotubes: 5 parts of acyl chloride carbon nanotubes, 1.2 parts of modifier and 20 parts of ethyl acetate are added into a reaction container, refluxed at 80° C. for 48 hours, and finally filtered, washed and dried to obtain modified carbon nanotubes; Step 4: Preparation of antistatic coating: (1) Add 48 parts of waterborne polyurethane, 4 parts of modified carbon nanotubes, 2 parts of ethylene glycol monomethyl ether, 0.3 parts of carboxymethyl cellulose, 0.3 parts of DE-H055 defoamer, 0.6 parts of PU-202 leveling agent and 15 parts of deionized water into a reaction container and stir for 3 hours; (2) Add 4 parts of ethylenediamine to (1) and stir for 1 hour to obtain an antistatic coating.

[0027] Example 2: A method for preparing an antistatic coating containing single-walled carbon nanotubes: Step 1: Preparation of chlorinated carbon nanotubes: (1) Add 10 parts of single-walled carbon nanotubes, 2 L of 98 wt% concentrated sulfuric acid and 0.667 L of 68 wt% concentrated nitric acid into a reaction container, stir and mix evenly, then heat to 80°C, soak for 6 hours, and finally filter, wash and dry to obtain acidified carbon nanotubes; (2) Add 8 parts of acidified carbon nanotubes and 2 L of dithionyl chloride into a reaction container, stir and mix evenly at room temperature, then heat to 55°C, continue stirring for 12 hours, stop stirring, and finally remove excess dithionyl chloride by rotary evaporation to obtain chlorinated carbon nanotubes; Step 2: Preparation of a modifier: (1) Add 1 part of 1-allylbenzotriazole, 1 part of N-tert-butylpropenyl-1-amine, 3 parts of allyl polyethylene glycol ether and 10 parts of deionized water into a reaction container, introduce nitrogen, and stir for 1 hour to obtain a reaction solution; (2) Keep stirring and heat the reaction solution to 50°C, then uniformly add a 10 wt% aqueous solution of ammonium persulfate (prepared by adding 0.22 parts of ammonium persulfate to deionized water) to the reaction solution within 0.5 hours. After the addition is complete, continue the reaction for 0.5 hours to terminate the reaction. Finally, remove the deionized water by vacuum distillation to obtain product A; (3) Mix 4 parts of product A and 1 .6 parts of methyl bromide are added to 15 parts of anhydrous ethanol, and the mixture is refluxed at 70°C for 6 hours to terminate the reaction. The anhydrous ethanol and excess methyl bromide are removed by vacuum distillation, and a 10 wt % aqueous sodium hydroxide solution is added thereto to adjust the pH value of the solution to 7.0. Finally, the mixture is separated and dried to obtain product B; (4) 4 parts of product B, 0.8 parts of 4,6-dihydroxy-2-mercaptopyrimidine, 0.2 parts of a photoinitiator and 10 parts of anhydrous ethanol are added to a reaction container, stirred and mixed evenly, and irradiated under 350 nm ultraviolet light for 1 minute to terminate the reaction. Finally, the anhydrous ethanol is removed by vacuum distillation to obtain a modifier; Step 3: Preparation of modified carbon nanotubes: 5 parts of acyl chloride carbon nanotubes, 0.5 parts of modifier and 20 parts of ethyl acetate are added into a reaction container, refluxed at 70° C. for 24 hours, and finally filtered, washed and dried to obtain modified carbon nanotubes; Step 4: Preparation of antistatic coating: (1) Add 48 parts of waterborne polyurethane, 4 parts of modified carbon nanotubes, 2 parts of ethylene glycol monomethyl ether, 0.3 parts of carboxymethyl cellulose, 0.3 parts of DE-H055 defoamer, 0.6 parts of PU-202 leveling agent and 15 parts of deionized water into a reaction container and stir for 3 hours; (2) Add 4 parts of ethylenediamine to (1) and stir for 1 hour to obtain an antistatic coating.

[0028] Example 3: A method for preparing an antistatic coating containing single-walled carbon nanotubes: Step 1: Preparation of chlorinated carbon nanotubes: (1) Add 10 parts of single-walled carbon nanotubes, 2 L of 98 wt% concentrated sulfuric acid and 0.667 L of 68 wt% concentrated nitric acid into a reaction container, stir and mix evenly, then heat to 80°C, soak for 6 hours, and finally filter, wash and dry to obtain acidified carbon nanotubes; (2) Add 8 parts of acidified carbon nanotubes and 2 L of dithionyl chloride into a reaction container, stir and mix evenly at room temperature, then heat to 55°C, continue stirring for 12 hours, stop stirring, and finally remove excess dithionyl chloride by rotary evaporation to obtain chlorinated carbon nanotubes; Step 2: Preparation of a modifier: (1) Add 2 parts of 1-allylbenzotriazole, 2 parts of N-tert-butylpropenyl-1-amine, 3 parts of allyl polyethylene glycol ether and 10 parts of deionized water into a reaction container, introduce nitrogen, and stir for 2 hours to obtain a reaction solution; (2) Keep stirring and heat the reaction solution to 70°C, then uniformly add a 10 wt% aqueous solution of ammonium persulfate (prepared by adding 0.22 parts of ammonium persulfate to deionized water) to the reaction solution within 2 hours. After the addition is complete, continue the reaction for 2 hours to terminate the reaction. Finally, remove the deionized water by vacuum distillation to obtain product A; (3) Mix 4 parts of product A and 1.6 parts of 1.5 parts of methyl bromide are added to 15 parts of anhydrous ethanol, and the mixture is refluxed at 80°C for 24 hours to terminate the reaction. The anhydrous ethanol and excess methyl bromide are removed by vacuum distillation, and a 10 wt % aqueous sodium hydroxide solution is added thereto to adjust the pH value of the solution to 7.0. The mixture is separated and dried to obtain product B. (4) 4 parts of product B, 1.6 parts of 4,6-dihydroxy-2-mercaptopyrimidine, 0.2 parts of a photoinitiator and 10 parts of anhydrous ethanol are added to a reaction container, stirred and mixed evenly, and irradiated under 350 nm ultraviolet light for 20 minutes to terminate the reaction. The anhydrous ethanol is removed by vacuum distillation to obtain a modifier. Step 3: preparing modified carbon nanotubes: adding 5 parts of acyl chloride carbon nanotubes, 2.5 parts of modifier and 20 parts of ethyl acetate into a reaction container, reflux reaction at 80° C. for 72 hours, and finally filtering, washing and drying to obtain modified carbon nanotubes; Step 4: Preparation of antistatic coating: (1) Add 48 parts of waterborne polyurethane, 4 parts of modified carbon nanotubes, 2 parts of ethylene glycol monomethyl ether, 0.3 parts of carboxymethyl cellulose, 0.3 parts of DE-H055 defoamer, 0.6 parts of PU-202 leveling agent and 15 parts of deionized water into a reaction container and stir for 3 hours; (2) Add 4 parts of ethylenediamine to (1) and stir for 1 hour to obtain an antistatic coating.

[0029] Based on Example 1, a control experiment was carried out, specifically Comparative Examples 1 to 5, as described below: Comparative Example 1: Comparative Example 1 is based on Example 1, with the following adjustments: single-walled carbon nanotubes are not treated, and other processes remain unchanged, specifically: A method for preparing an antistatic coating containing single-walled carbon nanotubes: Step 1: Preparation of modifier: (1) Add 1.5 parts of 1-allylbenzotriazole, 1.5 parts of N-tert-butylpropenyl-1-amine, 3 parts of allyl polyethylene glycol ether and 10 parts of deionized water into a reaction container, introduce nitrogen, and stir for 2 hours to obtain a reaction solution; (2) Keep stirring and heat the reaction solution to 70°C, then uniformly add a 10 wt% aqueous solution of ammonium persulfate (prepared by adding 0.22 parts of ammonium persulfate to deionized water) to the reaction solution within 2 hours. After the addition is complete, continue the reaction for 2 hours, terminate the reaction, and finally remove the deionized water by vacuum distillation to obtain product A; (3) Mix 4 parts of product A and 1. 6 parts of methyl bromide are added to 15 parts of anhydrous ethanol, and the mixture is refluxed at 80°C for 18 hours to terminate the reaction. The anhydrous ethanol and excess methyl bromide are removed by vacuum distillation, and a 10 wt % sodium hydroxide aqueous solution is added thereto to adjust the pH value of the solution to 7.0. The mixture is separated and dried to obtain product B. (4) 4 parts of product B, 1.2 parts of 4,6-dihydroxy-2-mercaptopyrimidine, 0.2 parts of a photoinitiator and 10 parts of anhydrous ethanol are added to a reaction container, stirred and mixed evenly, and irradiated under ultraviolet light at 350 nm for 10 minutes to terminate the reaction. The anhydrous ethanol is removed by vacuum distillation to obtain a modifier. Step 2: Preparation of modified carbon nanotubes: 5 parts of single-walled carbon nanotubes, 1.2 parts of a modifier and 20 parts of ethyl acetate were added into a reaction vessel, refluxed at 80° C. for 48 hours, and finally filtered, washed and dried to obtain modified carbon nanotubes; Step 4: Preparation of antistatic coating: (1) Add 48 parts of waterborne polyurethane, 4 parts of modified carbon nanotubes, 2 parts of ethylene glycol monomethyl ether, 0.3 parts of carboxymethyl cellulose, 0.3 parts of DE-H055 defoamer, 0.6 parts of PU-202 leveling agent and 15 parts of deionized water into a reaction container and stir for 3 hours; (2) Add 4 parts of ethylenediamine to (1) and stir for 1 hour to obtain an antistatic coating.

[0030] Comparative Example 2: Comparative Example 2 is based on Example 1, with the following adjustments: 1-allylbenzotriazole is not added during the preparation of the modifier, and other processes remain unchanged, specifically: A method for preparing an antistatic coating containing single-walled carbon nanotubes: Step 1: Preparation of chlorinated carbon nanotubes: (1) Add 10 parts of single-walled carbon nanotubes, 2 L of 98 wt% concentrated sulfuric acid and 0.667 L of 68 wt% concentrated nitric acid into a reaction container, stir and mix evenly, then heat to 80°C, soak for 6 hours, and finally filter, wash and dry to obtain acidified carbon nanotubes; (2) Add 8 parts of acidified carbon nanotubes and 2 L of dithionyl chloride into a reaction container, stir and mix evenly at room temperature, then heat to 55°C, continue stirring for 12 hours, stop stirring, and finally remove excess dithionyl chloride by rotary evaporation to obtain chlorinated carbon nanotubes; Step 2: Preparation of a modifier: (1) Add 2 parts of N-tert-butylpropenyl-1-amine, 4 parts of allyl polyethylene glycol ether and 10 parts of deionized water into a reaction container, introduce nitrogen, and stir for 2 hours to obtain a reaction solution; (2) Keep stirring and heat the reaction solution to 70°C, then uniformly add a 10 wt% aqueous solution of ammonium persulfate (prepared by adding 0.22 parts of ammonium persulfate to deionized water) to the reaction solution over 2 hours. After the addition is complete, continue the reaction for 2 hours, terminate the reaction, and finally remove the deionized water by vacuum distillation to obtain product A; (3) Add 4 parts of product A and 1.6 parts of methyl bromide into 15 parts of anhydrous ethanol, reflux reaction at 80°C for 18 hours, terminate the reaction, remove the anhydrous ethanol and excess bromomethyl ether by vacuum distillation, add 10wt% sodium hydroxide aqueous solution, adjust the solution pH to 7.0, and finally separate and dry to obtain product B; (4) add 4 parts of product B, 1.2 parts of 4,6-dihydroxy-2-mercaptopyrimidine, 0.2 parts of photoinitiator and 10 parts of anhydrous ethanol into a reaction container, stir and mix evenly, and irradiate under 350nm ultraviolet light for 10 minutes to terminate the reaction, and finally remove the anhydrous ethanol by vacuum distillation to obtain a modifier; Step 3: Preparation of modified carbon nanotubes: 5 parts of acyl chloride carbon nanotubes, 1.2 parts of modifier and 20 parts of ethyl acetate are added into a reaction container, refluxed at 80° C. for 48 hours, and finally filtered, washed and dried to obtain modified carbon nanotubes; Step 4: Preparation of antistatic coating: (1) Add 48 parts of waterborne polyurethane, 4 parts of modified carbon nanotubes, 2 parts of ethylene glycol monomethyl ether, 0.3 parts of carboxymethyl cellulose, 0.3 parts of DE-H055 defoamer, 0.6 parts of PU-202 leveling agent and 15 parts of deionized water into a reaction container and stir for 3 hours; (2) Add 4 parts of ethylenediamine to (1) and stir for 1 hour to obtain an antistatic coating.

[0031] Comparative Example 3: Comparative Example 3 is based on Example 1, with the following adjustments: N-tert-butylpropenyl-1-amine is not added during the preparation of the modifier, and other processes remain unchanged, specifically: A method for preparing an antistatic coating containing single-walled carbon nanotubes: Step 1: Preparation of chlorinated carbon nanotubes: (1) Add 10 parts of single-walled carbon nanotubes, 2 L of 98 wt% concentrated sulfuric acid and 0.667 L of 68 wt% concentrated nitric acid into a reaction container, stir and mix evenly, then heat to 80°C, soak for 6 hours, and finally filter, wash and dry to obtain acidified carbon nanotubes; (2) Add 8 parts of acidified carbon nanotubes and 2 L of dithionyl chloride into a reaction container, stir and mix evenly at room temperature, then heat to 55°C, continue stirring for 12 hours, stop stirring, and finally remove excess dithionyl chloride by rotary evaporation to obtain chlorinated carbon nanotubes; Step 2: Preparation of a modifier: (1) Add 2 parts of 1-allylbenzotriazole, 4 parts of allyl polyethylene glycol ether and 10 parts of deionized water into a reaction container, introduce nitrogen, and stir for 2 hours to obtain a reaction solution; (2) Keep stirring and heat the reaction solution to 70°C, then uniformly add a 10 wt% aqueous solution of ammonium persulfate (prepared by adding 0.22 parts of ammonium persulfate to deionized water) to the reaction solution over 2 hours. After the addition is complete, continue the reaction for 2 hours, terminate the reaction, and finally remove the deionized water by vacuum distillation to obtain product A; (3) Add 4 parts of product A and 1.6 parts of methyl bromide to 1 5 parts of anhydrous ethanol, reflux reaction at 80°C for 18 hours, terminate the reaction, remove the anhydrous ethanol and excess bromomethyl ether by vacuum distillation, add 10wt% sodium hydroxide aqueous solution, adjust the solution pH to 7.0, and finally separate and dry to obtain product B; (4) add 4 parts of product B, 1.2 parts of 4,6-dihydroxy-2-mercaptopyrimidine, 0.2 parts of photoinitiator and 10 parts of anhydrous ethanol into a reaction container, stir and mix evenly, and irradiate under 350nm ultraviolet light for 10 minutes to terminate the reaction, and finally remove the anhydrous ethanol by vacuum distillation to obtain a modifier; Step 3: Preparation of modified carbon nanotubes: 5 parts of acyl chloride carbon nanotubes, 1.2 parts of modifier and 20 parts of ethyl acetate are added into a reaction container, refluxed at 80° C. for 48 hours, and finally filtered, washed and dried to obtain modified carbon nanotubes; Step 4: Preparation of antistatic coating: (1) Add 48 parts of waterborne polyurethane, 4 parts of modified carbon nanotubes, 2 parts of ethylene glycol monomethyl ether, 0.3 parts of carboxymethyl cellulose, 0.3 parts of DE-H055 defoamer, 0.6 parts of PU-202 leveling agent and 15 parts of deionized water into a reaction container and stir for 3 hours; (2) Add 4 parts of ethylenediamine to (1) and stir for 1 hour to obtain an antistatic coating.

[0032] Comparative Example 4: Comparative Example 4 is based on Example 1, with the following adjustments: no allyl polyglycol ether is added during the preparation of the modifier, and other processes remain unchanged, specifically: A method for preparing an antistatic coating containing single-walled carbon nanotubes: Step 1: Preparation of chlorinated carbon nanotubes: (1) Add 10 parts of single-walled carbon nanotubes, 2 L of 98 wt% concentrated sulfuric acid and 0.667 L of 68 wt% concentrated nitric acid into a reaction container, stir and mix evenly, then heat to 80°C, soak for 6 hours, and finally filter, wash and dry to obtain acidified carbon nanotubes; (2) Add 8 parts of acidified carbon nanotubes and 2 L of dithionyl chloride into a reaction container, stir and mix evenly at room temperature, then heat to 55°C, continue stirring for 12 hours, stop stirring, and finally remove excess dithionyl chloride by rotary evaporation to obtain chlorinated carbon nanotubes; Step 2: Preparation of a modifier: (1) Add 3 parts of 1-allylbenzotriazole, 3 parts of N-tert-butylpropenyl-1-amine and 10 parts of deionized water into a reaction container, introduce nitrogen, and stir for 2 hours to obtain a reaction solution; (2) Keep stirring and heat the reaction solution to 70°C, then uniformly add a 10 wt% aqueous solution of ammonium persulfate (prepared by adding 0.22 parts of ammonium persulfate to deionized water) to the reaction solution over 2 hours. After the addition is complete, continue the reaction for 2 hours, terminate the reaction, and finally remove the deionized water by vacuum distillation to obtain product A; (3) Add 4 parts of product A and 1.6 parts of methyl bromide to (4) adding 4 parts of product B, 1.2 parts of 4,6-dihydroxy-2-mercaptopyrimidine, 0.2 parts of photoinitiator and 10 parts of anhydrous ethanol into a reaction container, stirring and mixing, and irradiating under 350nm ultraviolet light for 10min to terminate the reaction. Finally, removing the anhydrous ethanol by vacuum distillation to obtain a modifier. Step 3: Preparation of modified carbon nanotubes: 5 parts of acyl chloride carbon nanotubes, 1.2 parts of modifier and 20 parts of ethyl acetate are added into a reaction container, refluxed at 80° C. for 48 hours, and finally filtered, washed and dried to obtain modified carbon nanotubes; Step 4: Preparation of antistatic coating: (1) Add 48 parts of waterborne polyurethane, 4 parts of modified carbon nanotubes, 2 parts of ethylene glycol monomethyl ether, 0.3 parts of carboxymethyl cellulose, 0.3 parts of DE-H055 defoamer, 0.6 parts of PU-202 leveling agent and 15 parts of deionized water into a reaction container and stir for 3 hours; (2) Add 4 parts of ethylenediamine to (1) and stir for 1 hour to obtain an antistatic coating.

[0033] Comparative Example 5: Comparative Example 5 is based on Example 1, with the following adjustments: single-walled carbon nanotubes are directly added to the coating, and the rest remain unchanged, specifically: A method for preparing an antistatic coating containing single-walled carbon nanotubes: Step 1: Preparation of antistatic coating: (1) Add 48 parts of waterborne polyurethane, 4 parts of single-walled carbon nanotubes, 2 parts of ethylene glycol monomethyl ether, 0.3 parts of carboxymethyl cellulose, 0.3 parts of DE-H055 defoamer, 0.6 parts of PU-202 leveling agent and 15 parts of deionized water into a reaction container and stir for 3 hours; (2) Add 4 parts of ethylenediamine to (1) and stir for 1 hour to obtain an antistatic coating.

[0034] Performance test: (1) The antistatic coatings prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were placed for 7 days and their status was observed; (2) Each antistatic coating was evenly coated on a PET film using a TQC VF1502 Baker coater, and the coating wet weight was controlled at 6±0.2 g / m 2 , and ensure that the coating film has no shrinkage cavities, and after coating, place it at 100°C for drying to obtain an antistatic coating; perform relevant performance tests on the antistatic coating, and the specific test items and methods are as follows: ① Antistatic performance: Use GM3111 surface resistance meter to test the surface resistance of antistatic coating, test 3 times and take the average value; use surface resistance to characterize the antistatic performance of antistatic coating, the lower the surface resistance, the better the antistatic performance; ② Anti-peeling performance: stick a 20cm×20cm transparent tape on the antistatic coating, pull it, and observe whether it falls off; ③ Anti-aging performance: Use UVA340Lamp to irradiate the antistatic coating for 72 hours; then continue to use 20cm×20cm transparent tape to stick on the antistatic coating, pull it, and observe whether it falls off; the specific test results are shown in Table 1 below: Table 1

[0035] Result analysis: From the test results in Table 1, it can be seen that the modified carbon nanotubes prepared in the present invention by acidifying and chlorinating single-walled carbon nanotubes and then modifying them with a modifier have obvious improvements in the antistatic property and dispersibility of waterborne polyurethane coatings; in addition, from the results of adhesion fastness, the modified carbon nanotubes also have a certain degree of influence on the adhesion performance of the antistatic coating; in particular, the benzotriazole structure on the modified carbon nanotubes has a significant effect on the aging resistance of the antistatic coating.

[0036] In summary, the present invention prepares an antistatic coating containing highly dispersed single-walled carbon nanotubes, which not only exhibits excellent antistatic properties, but also has excellent aging resistance, and the coating obtained by coating has a longer application life.

[0037] 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing an antistatic coating containing single-walled carbon nanotubes, characterized in that: The following steps are involved: Step 1: single-walled carbon nanotubes are subjected to acidification treatment and acyl chloride treatment in sequence to obtain acyl chloride carbon nanotubes; Step 2: (1) 1-allylbenzotriazole, N-tert-butylpropenyl-1-amine and allyl polyethylene glycol ether initiate polymerization to obtain product A; (2) product A undergoes substitution reaction with bromomethyl ether to obtain product B; (3) product B undergoes click reaction with 4,6-dihydroxy-2-mercaptopyrimidine to obtain a modifier; Step 3: modifying the acyl chloride carbon nanotubes with a modifying agent to obtain modified carbon nanotubes; Step 4: Evenly mix the waterborne polyurethane, modified carbon nanotubes, curing agent, film-forming aid, tackifier, defoamer, leveling agent and deionized water to obtain an antistatic coating.

2. The method for preparing an antistatic coating containing single-walled carbon nanotubes according to claim 1, characterized in that: The preparation method of the acyl chloride carbon nanotubes is: (1) adding single-walled carbon nanotubes, concentrated sulfuric acid and concentrated nitric acid into a reaction container, stirring and mixing them evenly, then heating to 50-100° C., soaking for 1-12 hours, filtering, washing and drying to obtain acidified carbon nanotubes; (2) Add the acidified carbon nanotubes and dichlorothionyl into a reaction vessel, stir and mix them evenly at room temperature, then raise the temperature to 50-70°C, continue stirring for 1-24 hours, stop stirring, and obtain acyl chloride carbon nanotubes by rotary evaporation.

3. The method for preparing an antistatic coating containing single-walled carbon nanotubes according to claim 2, characterized in that: The ratio of the single-walled carbon nanotubes, concentrated sulfuric acid and concentrated nitric acid is (1-2) g:30 mL:10 mL; the ratio of the acidified carbon nanotubes and dichlorothionyl is (1-5) g:100 mL.

4. The method for preparing an antistatic coating containing single-walled carbon nanotubes according to claim 1, characterized in that: The preparation method of the modifier is: (1) adding 1-allylbenzotriazole, N-tert-butylpropenyl-1-amine, allyl polyethylene glycol ether and deionized water into a reaction container, introducing nitrogen gas, and stirring for 1 to 2 hours to obtain a reaction solution; (2) Keep stirring, raise the temperature of the reaction solution to 50-80°C, then uniformly add the initiator to the reaction solution over 0.5-2 hours. After the addition is complete, continue the reaction for 0.5-2 hours, terminate the reaction, and obtain product A by vacuum distillation; (3) Add product A and bromomethyl ether to anhydrous ethanol, reflux for reaction at 70-85°C for 6-24 hours, terminate the reaction, remove anhydrous ethanol and excess bromomethyl ether by vacuum distillation, add sodium hydroxide aqueous solution, adjust the pH value of the solution to 6.8-7.2, separate and dry to obtain product B; (4) Add product B, 4,6-dihydroxy-2-mercaptopyrimidine, a photoinitiator and anhydrous ethanol into a reaction container, stir and mix evenly, and irradiate under ultraviolet light at 350-370 nm for 1-20 min to terminate the reaction. Then, distill under reduced pressure to obtain a modifier.

5. The method for preparing an antistatic coating containing single-walled carbon nanotubes according to claim 4, characterized in that: The mass ratio of the 1-allylbenzotriazole, N-tert-butylpropenyl-1-amine, allyl polyethylene glycol ether and the initiator is (1-2):(1-2):3:(0.15-0.3); the mass ratio of the product A and methyl bromide is 5:2; the mass ratio of the product B, 4,6-dihydroxy-2-mercaptopyrimidine and the photoinitiator is 5:(1-2):(0.15-0.3).

6. The method for preparing an antistatic coating containing single-walled carbon nanotubes according to claim 1, characterized in that: The preparation method of the modified carbon nanotubes comprises: adding acyl chloride carbon nanotubes, a modifier and ethyl acetate into a reaction container, performing reflux reaction at 70-90° C. for 24-72 hours, and finally filtering, washing and drying to obtain the modified carbon nanotubes.

7. The method for preparing an antistatic coating containing single-walled carbon nanotubes according to claim 6, characterized in that: The mass ratio of the acyl chloride carbon nanotubes to the modifier is 1:(0.1-0.5).

8. The method for preparing an antistatic coating containing single-walled carbon nanotubes according to claim 1, characterized in that: The preparation method of the antistatic coating is: (1) Add waterborne polyurethane, modified carbon nanotubes, film-forming agent, tackifier, defoamer, leveling agent and deionized water into a reaction vessel and stir for 1 to 3 hours; (2) Add curing agent to (1), stir and mix for 0.5 to 1 hour to obtain an antistatic coating.

9. The method for preparing an antistatic coating containing single-walled carbon nanotubes according to claim 1, characterized in that: The film-forming aid includes any one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether and ethylene glycol; the viscosity enhancer is a cellulose thickener; and the curing agent is an amine curing agent.

10. The antistatic coating prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The antistatic coating comprises the following components: by weight, 40-50 parts of waterborne polyurethane, 1-6 parts of modified carbon nanotubes, 2-5 parts of curing agent, 1-3 parts of film-forming aid, 0.1-0.5 parts of tackifier, 0.1-0.5 parts of defoamer, 0.1-1 parts of leveling agent and 10-20 parts of deionized water.

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