Solid conductive powder coating composition and preparation method thereof

Abstract

The invention discloses a solid conductive powder coating composition and a preparation method thereof, and belongs to the technical field of powder coatings. The preparation method comprises the following steps: adding epoxy resin, modified fibers, modified graphene oxide, modified 1, 6-dihydroxynaphthalene, carbon black, 2-methylimidazole, a flatting agent and barium sulfate into a stirrer, mixing at a high speed of 300-400r / min for 5-10min, then putting the mixed material into a double-screw extruder for melt extrusion, tabletting, cooling, crushing and sieving to obtain the solid conductive powder coating composition. The solid conductive powder coating composition disclosed by the invention has good conductivity and also improves the corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of powder coatings, more particularly, relates to a solid-state conductive powder coating composition and a preparation method thereof. BACKGROUND

[0002] Conductive coatings can make the surface of the coated object have a certain degree of conductivity or antistatic ability, which has important application value in the electronic and electrical, communication equipment and other industries. With the improvement of people's requirements for environmental protection, traditional liquid conductive coatings containing solvents are gradually eliminated due to pollution caused by volatile organic compounds, and solid-state powder coatings without solvent emission have become the focus of industry transformation. However, the existing conductive powder coatings are prone to problems such as brittle coating, difficult dispersion, and the like, and the coatings also need to consider basic properties such as adhesion and weather resistance. Therefore, how to avoid this phenomenon is the key to solving the problem. For example, the patent with publication number CN120005488A discloses a powder coating composition with stable antistatic effect and a cured coating thereof. The cured coating has stable and excellent antistatic effect, and is particularly suitable for preparing coating layers on the surfaces of related metal workpieces containing electronic components with high requirements for electrostatic environment. However, the corrosion resistance needs to be improved. SUMMARY

[0003] TECHNICAL PROBLEM

[0004] In view of the deficiencies of the prior art, the present application provides a solid-state conductive powder coating composition and a preparation method thereof. The solid-state conductive powder coating composition of the present application not only has good conductive properties, but also improves the corrosion resistance.

[0005] TECHNICAL SCHEME

[0006] In order to solve the above problems, the technical scheme adopted by the present application is as follows:

[0007] The preparation method of the solid-state conductive powder coating composition of the present application comprises the following steps:

[0008] (1) adding 1,6-dihydroxynaphthalene, epichlorohydrin, tetramethylammonium bromide and sodium hydroxide into a reactor to obtain a crude product, then dissolving the crude product in methyl isobutyl ketone, adding polyethylene glycol and 50% liquid caustic, and reacting to obtain an intermediate 1;

[0009] (2) adding 1,3-dimethyl-6-amino uracil and the intermediate 1 into N,N-dimethylformamide solvent, stirring and reacting to obtain modified 1,6-dihydroxynaphthalene;

[0010] (3) adding graphene oxide into deionized water, ultrasonic dispersion, and dropping L-glutamic acid into the dispersion to obtain modified graphene oxide;

[0011] (4) Recovering polyester fiber clothes waste to obtain fiber material, adding γ-aminopropyl triethoxysilane, hydrolyzing, and reacting to obtain modified fiber;

[0012] (5) Adding epoxy resin, modified fiber, modified graphene oxide, modified 1,6-dihydroxynaphthalene, carbon black, 2-methyl imidazole, leveling agent, and barium sulfate into a blender, mixing at a high speed of 300-400 r / min for 5-10 min, then putting the mixed material into a twin-screw extruder for melt extrusion, tabletting, cooling, crushing, and sieving to obtain a solid conductive powder coating composition.

[0013] Further, in the (1) step, 4.48-4.52 g of 1,6-dihydroxynaphthalene, 51.8-51.9 g of epichlorohydrin, and 0.06-0.07 g of tetramethylammonium bromide are added into a reactor, mixed uniformly, nitrogen is introduced, the temperature is raised to 65-70 °C, 2.68-2.72 g of sodium hydroxide with a molar mass of 40 g / mol is added, and reacted for 2-4 h. After the reaction is completed, filtration, washing, and obtaining a crude product are performed. Then, the crude product is dissolved in 30-35 mL of methyl isobutyl ketone, the temperature is raised to 105-100 °C, 1.04-1.08 g of polyethylene glycol is added, 10-10.5 g of 50% liquid alkali is added dropwise, and the reaction is continued for 3-5 h. After the reaction is completed, washing, removal of the solvent, and distillation are performed to obtain intermediate 1.

[0014] In the above step, the phenolic hydroxyl group in 1,6-dihydroxynaphthalene is activated under the action of alkali to become a nucleophile, attacks epichlorohydrin, and makes it ring-opening to generate a linear chlorohydrin intermediate. The intermediate is activated again under the action of alkali to perform intramolecular cyclization to generate a crude product. The crude product is dissolved in methyl isobutyl ketone, polyethylene glycol is added, the hydroxyl group on the end group of polyethylene glycol can undergo nucleophilic substitution reaction with the residual organic chlorine to generate harmless sodium chloride, thereby reducing the total chlorine content of the product and obtaining high-purity intermediate 1.

[0015] Further, in the (2) step, 6.42-6.46 g of 1,3-dimethyl-6-amino uracil and 4.53-4.57 g of intermediate 1 are added into 40-50 mL of N,N-dimethylformamide solvent, mixed under stirring, and reacted at 50-70 °C for 6-8 h. After the reaction is completed, cooling to room temperature, washing, and drying are performed, and purification is performed to obtain modified 1,6-dihydroxynaphthalene.

[0016] In the above step, the amino group in 1,3-dimethyl-6-amino uracil has a lone pair of electrons and has strong nucleophilicity, which attacks the carbon atom of the epoxy group to cause ring-opening of the epoxy ring to form modified 1,6-dihydroxynaphthalene with ether-amine structure.

[0017] Further, in the (3) step, 0.7-0.8 g of graphene oxide is added to 155-160 mL of deionized water, ultrasonic dispersion is carried out for 25-30 min to obtain a dispersion liquid, 2.5-2.54 g of L-glutamic acid is dissolved in 50-55 mL of 0.1 mol / L sodium hydroxide solution, mechanical stirring is carried out for 15-20 min, after stirring, it is added dropwise into the dispersion liquid, ultrasonic dispersion is continued for 15-20 min, stirring is carried out at room temperature under nitrogen protection for 22-26 h, after the reaction is completed, washing is carried out, vacuum drying is carried out at 45-50 DEG C, grinding is carried out, and modified graphene oxide is obtained.

[0018] In the above step, the amino group of L-glutamic acid attacks the epoxy group on the graphene oxide as a nucleophile under alkaline conditions, causes ring opening of the epoxy ring to form an ether-amine structure, grafts L-glutamic acid onto the graphene oxide, and obtains modified graphene oxide.

[0019] Further, in the (4) step, polyester fiber clothing waste is recovered, is crushed to a length of 0.5-1 mm to obtain a fiber material, 28-30 mL of ethanol is added to a reactor, the solution pH is adjusted with glacial acetic acid, then 9-10 mL of gamma-aminopropyl triethoxysilane is added, hydrolysis is carried out for 10-14 h, after the hydrolysis is completed, 7.6-7.7 g of the fiber material is added, is mixed uniformly, stirring reaction is carried out for 8-12 h, after the reaction is completed, suction filtration is carried out, vacuum drying is carried out at 100-105 DEG C for 10-12 h, and modified fiber is obtained.

[0020] In the above step, the triethoxysilyl group in the gamma-aminopropyl triethoxysilane reacts with the hydroxyl group on the fiber material after hydrolysis, is grafted onto the fiber material, and forms modified fiber with an amino group on the surface.

[0021] Further, in the (5) step, the weight parts of the components are as follows: 40-50 parts of epoxy resin, 1-3 parts of modified fiber, 2-3 parts of modified graphene oxide, 1-1.5 parts of modified 1,6-dihydroxynaphthalene, 1-1.5 parts of carbon black, 1-2 parts of 2-methylimidazole, 0.2-0.3 parts of a leveling agent, and 1-3 parts of barium sulfate.

[0022] Further, in the (5) step, the extrusion temperature is 90-110 DEG C.

[0023] The application also protects a solid-state conductive powder coating composition prepared by the preparation method in any one of the above.

[0024] Beneficial technical effects

[0025] Compared with the prior art, the beneficial effects of the application are as follows:

[0026] (1) The epoxy resin can form a stable crosslinking network with modified fiber, modified graphene oxide and modified 1,6-dihydroxynaphthalene. The modified 1,6-dihydroxynaphthalene has a rigid naphthalene ring and a uracil ring, and the uracil ring is a strong multiple hydrogen bond donor and acceptor, which can form an extremely firm and dense hydrogen bond network on the surface of the metal substrate, thereby improving the physical properties and corrosion resistance of the coating. After the graphene oxide is modified by L-glutamic acid, the amine group and part of the polar groups in the graphene oxide form covalent bonds with the epoxy groups in the epoxy resin, which can improve the dispersibility of the graphene oxide and increase the crosslinking density of the epoxy resin, effectively expand or block the diffusion path of the corrosion medium, thereby achieving the effect of corrosion resistance. Moreover, as the main conductive filler, the graphene can construct an efficient conductive network after its dispersibility is improved, and the carbon black as an auxiliary conductive filler can fill the gaps between the graphene and improve the uniformity of the conductive performance and the conductivity of the coating. The modified fiber material can play the advantages of fiber toughening and wear resistance, thereby enhancing the physical properties of the coating, and the modified fiber material can be better crosslinked with the epoxy resin, thereby enhancing the barrier corrosion effect.

[0027] (2) The solid-state conductive powder coating composition of the present application is obtained by the preparation method of the present application and has all the beneficial effects of the preparation method of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the reaction synthesis formula of modified 1,6-dihydroxynaphthalene.

[0029] Figure 2 is the nuclear magnetic hydrogen spectrum of intermediate 1.

[0030] Figure 3 is the nuclear magnetic hydrogen spectrum of modified 1,6-dihydroxynaphthalene. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application is described clearly and completely. Obviously, the described embodiments are part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in 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.

[0032] In order to better understand the above technical scheme, the above technical scheme will be described in detail in combination with the drawings in the specification and specific embodiments.

[0033] The reagents used in the following specific embodiments are analytical pure, and the other:

[0034] Epoxy resin: the grade is E-44, and the manufacturer is Hubei Wanye Pharmaceutical Co., Ltd.;

[0035] Graphene oxide: industrial grade, code XFSG01, flake diameter < 20 um, thickness ≤ 5 nm, manufacturer Nanjing Xianfeng Nanometer Material Technology Co., Ltd.

[0036] Carbon black: brand vulcan xc-72r, manufacturer Cabot Corporation;

[0037] Leveling agent: brand GLP788, manufacturer Ningbo Nanhai Chemical Co., Ltd.

[0038] Example 1

[0039] The embodiment provides a solid-state conductive powder coating composition, and a preparation method thereof specifically comprises the following steps:

[0040] (1) 4.48 g of 1,6-dihydroxynaphthalene, 51.8 g of epichlorohydrin, 0.06 g of tetramethylammonium bromide are added into a reactor, mixed uniformly, nitrogen is introduced, the temperature is raised to 65 DEG C, then 2.68 g of sodium hydroxide with a molar mass of 40 g / mol is added, and reaction is carried out for 2 h; after reaction, filtration, washing, and obtaining a crude product, the crude product is dissolved in 30 mL of methyl isobutyl ketone, the temperature is raised to 105 DEG C, 1.04 g of polyethylene glycol is added, 10 g of 50% liquid alkali is added dropwise, and reaction is continued for 3 h; after reaction, washing, removal of solvent, and distillation, an intermediate 1 is obtained;

[0041] Figure 2 The intermediate 1 is a nuclear magnetic hydrogen spectrum, and as shown in Figure 2 It can be seen that there are obvious [-O-CH2-] characteristic peaks at δ=3.9-4.3, which indicates that 1,6-dihydroxynaphthalene and epichlorohydrin successfully react to obtain the intermediate 1;

[0042] (2) 6.42 g of 1,3-dimethyl-6-amino uracil, 4.53 g of the intermediate 1 are added into 40 mL of N,N-dimethylformamide solvent, stirring and mixing, reaction is carried out at 50 DEG C for 6 h; after reaction, cooling to room temperature, washing and drying, and purification, modified 1,6-dihydroxynaphthalene is obtained;

[0043] Figure 3 The modified 1,6-dihydroxynaphthalene is a nuclear magnetic hydrogen spectrum, and as shown in Figure 3 It can be seen that there are obvious [-OH] characteristic peaks at δ=5.3-5.4 and [-NH-] characteristic peaks at δ=10.9-11, which indicates that 1,3-dimethyl-6-amino uracil and the intermediate 1 successfully react to obtain the modified 1,6-dihydroxynaphthalene;

[0044] (3) 0.7 g of graphene oxide was added to 155 mL of deionized water and ultrasonically dispersed for 25 min to obtain a dispersion liquid, 2.5 g of L-glutamic acid was dissolved in 50 mL of 0.1 mol / L sodium hydroxide solution, mechanically stirred for 15 min, and then added dropwise to the dispersion liquid after stirring, and ultrasonically dispersed for 15 min, stirred at room temperature under nitrogen protection for 22 h, after the reaction was completed, washed, vacuum dried at 45℃, ground, and modified graphene oxide was obtained;

[0045] (4) The polyester fiber clothing waste was recovered, crushed to a length of 0.5 mm to obtain a fiber material, 28 mL of ethanol was added to a reactor, the solution pH was adjusted to 3 with glacial acetic acid, then 9 mL of γ-aminopropyl triethoxysilane was added, hydrolyzed for 10 h, after the hydrolysis was completed, 7.6 g of the fiber material was added, mixed uniformly, and stirred for 8 h, after the reaction was completed, suction filtration was performed, and vacuum drying was performed at 100℃ for 10 h to obtain modified fibers;

[0046] (5) 40 parts by weight of epoxy resin, 1 part by weight of modified fiber, 2 parts by weight of modified graphene oxide, 1 part by weight of modified 1,6-dihydroxynaphthalene, 1 part by weight of carbon black, 1 part by weight of 2-methylimidazole, 0.2 parts by weight of leveling agent, and 1 part by weight of barium sulfate were added to a blender, mixed at a high speed of 300 r / min for 5 min, then the mixed material was placed into a twin-screw extruder for melt extrusion, the extrusion temperature was 90℃, and after tabletting and cooling, crushing, and sieving, a solid-state conductive powder coating composition was obtained.

[0047] Example 2

[0048] The present embodiment provides a solid-state conductive powder coating composition, and a preparation method thereof specifically includes the following steps:

[0049] (1) 4.52 g of 1,6-dihydroxynaphthalene, 51.9 g of epichlorohydrin, and 0.07 g of tetramethylammonium bromide were added to a reactor, mixed uniformly, nitrogen was introduced, and the temperature was raised to 70℃, then 2.72 g of sodium hydroxide with a molar mass of 40 g / mol was added, reacted for 4 h, after the reaction was completed, filtration was performed, and the crude product was washed to obtain a crude product, then the crude product was dissolved in 35 mL of methyl isobutyl ketone, the temperature was raised to 110℃, 1.08 g of polyethylene glycol was added, and 10.5 g of 50% liquid alkali was added dropwise, and the reaction was continued for 5 h, after the reaction was completed, washing was performed, the solvent was removed, and distillation was performed to obtain an intermediate 1;

[0050] (2) 6.46 g of 1,3-dimethyl-6-amino uracil and 4.57 g of the intermediate 1 were added to 50 mL of N,N-dimethylformamide solvent, stirred and mixed, reacted at 70℃ for 8 h, after the reaction was completed, the temperature was cooled to room temperature, washing and drying were performed, and purification was performed to obtain modified 1,6-dihydroxynaphthalene;

[0051] (3) 0.8 g of graphene oxide was added to 160 mL of deionized water and ultrasonically dispersed for 30 min to obtain a dispersion liquid, 2.54 g of L-glutamic acid was dissolved in 55 mL of 0.1 mol / L sodium hydroxide solution, mechanically stirred for 20 min, and then added dropwise to the dispersion liquid after stirring, and ultrasonically dispersed for 20 min, stirred at room temperature under nitrogen protection for 26 h, after the reaction was completed, washed, vacuum dried at 50°C, ground, and modified graphene oxide was obtained;

[0052] (4) The polyester fiber clothing waste was recovered, crushed to a length of 1 mm to obtain a fiber material, 30 mL of ethanol was added to a reactor, the solution pH was adjusted to 3 with glacial acetic acid, then 10 mL of γ-aminopropyl triethoxysilane was added, and hydrolysis was performed for 14 h, after the hydrolysis was completed, 7.7 g of the fiber material was added, mixed uniformly, and stirred for 12 h, after the reaction was completed, suction filtration was performed, and vacuum drying was performed at 105°C for 12 h to obtain modified fibers;

[0053] (5) 50 parts by weight of epoxy resin, 3 parts by weight of modified fibers, 3 parts by weight of modified graphene oxide, 1.5 parts by weight of modified 1,6-dihydroxynaphthalene, 1.5 parts by weight of carbon black, 2 parts by weight of 2-methylimidazole, 0.3 parts by weight of a leveling agent, and 3 parts by weight of barium sulfate were added to a blender and mixed at a high speed of 400 r / min for 10 min, then the mixed material was placed into a twin-screw extruder and melt-extruded at an extrusion temperature of 110°C, and after tabletting and cooling, the material was crushed, sieved, and a solid-state conductive powder coating composition was obtained.

[0054] Example 3

[0055] The present embodiment provides a solid-state conductive powder coating composition, and a preparation method thereof specifically includes the following steps:

[0056] (1) 4.5 g of 1,6-dihydroxynaphthalene, 51.85 g of epoxy chloropropane, and 0.06 g of tetramethylammonium bromide were added to a reactor, mixed uniformly, nitrogen was introduced, and the temperature was raised to 68°C, then 2.7 g of sodium hydroxide with a molar mass of 40 g / mol was added, and the reaction was performed for 3 h, after the reaction was completed, filtration was performed, and the product was washed to obtain a crude product, then the crude product was dissolved in 33 mL of methyl isobutyl ketone, the temperature was raised to 108°C, 1.06 g of polyethylene glycol was added, and 10.2 g of 50% liquid alkali was added dropwise, and the reaction was continued for 4 h, after the reaction was completed, the product was washed, the solvent was removed, and distillation was performed to obtain an intermediate 1;

[0057] (2) 6.44 g of 1,3-dimethyl-6-aminoformyluracil and 4.55 g of the intermediate 1 were added to 45 mL of N,N-dimethylformamide solvent, the mixture was stirred, reacted at 60°C for 7 h, after the reaction was completed, it was cooled to room temperature, washed and dried, purified to obtain modified 1,6-dihydroxynaphthalene;

[0058] (3) 0.75 g of graphene oxide was added to 158 mL of deionized water, ultrasonic dispersion was performed for 28 min to obtain a dispersion liquid, 2.52 g of L-glutamic acid was dissolved in 52 mL of 0.1 mol / L sodium hydroxide solution, mechanical stirring was performed for 18 min, after stirring, it was added dropwise to the dispersion liquid, ultrasonic dispersion was continued for 18 min, stirring was performed at room temperature under nitrogen protection for 24 h, after the reaction was completed, it was washed, vacuum dried at 48°C, and ground to obtain modified graphene oxide;

[0059] (4) Polyester fiber clothing waste was recovered, and was crushed to a length of 0.8 mm to obtain fiber material, 29 mL of ethanol was added to a reactor, the solution pH was adjusted to 3 with glacial acetic acid, then 9.5 mL of γ-aminopropyl triethoxysilane was added, hydrolysis was performed for 12 h, after the hydrolysis was completed, 7.65 g of the fiber material was added, mixed uniformly, and stirring was performed for 10 h, after the reaction was completed, it was suction filtered, and vacuum dried at 102°C for 11 h to obtain modified fiber;

[0060] (5) 45 parts by weight of epoxy resin, 2 parts by weight of modified fiber, 2 parts by weight of modified graphene oxide, 1.2 parts by weight of modified 1,6-dihydroxynaphthalene, 1 part by weight of carbon black, 1.5 parts by weight of 2-methylimidazole, 0.2 parts by weight of leveling agent, and 2 parts by weight of barium sulfate were added to a stirrer, high-speed mixing was performed at 350 r / min for 8 min, then the mixed material was placed into a twin-screw extruder for melt extrusion, the extrusion temperature was 100°C, after tabletting and cooling, crushing, and sieving, a solid-state conductive powder coating composition was obtained.

[0061] Example 4

[0062] The present embodiment provides a solid-state conductive powder coating composition, and a preparation method thereof specifically includes the following steps:

[0063] (1) 4.49 g of 1,6-dihydroxynaphthalene, 51.82 g of epichlorohydrin, and 0.06 g of tetramethylammonium bromide were added to a reactor, mixed uniformly, nitrogen was introduced, and the temperature was raised to 66°C, then 2.69 g of sodium hydroxide with a molar mass of 40 g / mol was added, and reacted for 2 h, after the reaction was completed, it was filtered and washed to obtain a crude product, then the crude product was dissolved in 31 mL of methyl isobutyl ketone, the temperature was raised to 106°C, 1.05 g of polyethylene glycol was added, and 10.1 g of 50% liquid alkali was added dropwise, and the reaction was continued for 3 h, after the reaction was completed, it was washed, the solvent was removed, and distillation was performed to obtain the intermediate 1;

[0064] (2) 6.43 g of 1,3-dimethyl-6-aminoformyluracil and 4.54 g of intermediate 1 were added to 42 mL of N,N-dimethylformamide solvent, the mixture was stirred, reacted at 55°C for 6 h, after the reaction was completed, it was cooled to room temperature, washed and dried, and purified to obtain modified 1,6-dihydroxynaphthalene;

[0065] (3) 0.72 g of graphene oxide was added to 156 mL of deionized water, ultrasonic dispersion was performed for 26 min to obtain a dispersion liquid, 2.51 g of L-glutamic acid was dissolved in 51 mL of 0.1 mol / L sodium hydroxide solution, mechanical stirring was performed for 16 min, after stirring, it was added dropwise to the dispersion liquid, ultrasonic dispersion was continued for 16 min, stirring was performed at room temperature under nitrogen protection for 23 h, after the reaction was completed, it was washed, vacuum dried at 46°C, and ground to obtain modified graphene oxide;

[0066] (4) polyester fiber clothing waste was recovered, and was crushed to a length of 0.6 mm to obtain fiber material, 28.5 mL of ethanol was added to a reactor, the solution pH was adjusted to 3 with glacial acetic acid, then 9.2 mL of γ-aminopropyl triethoxysilane was added, hydrolysis was performed for 11 h, after the hydrolysis was completed, 7.62 g of the fiber material was added, mixed uniformly, and stirring was performed for 9 h, after the reaction was completed, it was suction filtered, and vacuum dried at 101°C for 10 h to obtain modified fiber;

[0067] (5) 42 parts by weight of epoxy resin, 1 part by weight of modified fiber, 2 parts by weight of modified graphene oxide, 1 part by weight of modified 1,6-dihydroxynaphthalene, 1 part by weight of carbon black, 2 parts by weight of 2-methylimidazole, 0.2 parts by weight of leveling agent, and 2 parts by weight of barium sulfate were added to a stirrer, high-speed mixing was performed at 320 r / min for 6 min, then the mixed material was placed into a twin-screw extruder for melt extrusion, the extrusion temperature was 95°C, after tabletting and cooling, crushing, and sieving, a solid-state conductive powder coating composition was obtained.

[0068] Example 5

[0069] The present embodiment provides a solid-state conductive powder coating composition, and a preparation method thereof specifically includes the following steps:

[0070] (1) 4.51 g of 1,6-dihydroxynaphthalene, 51.88 g of epichlorohydrin, 0.07 g of tetramethylammonium bromide were added to a reactor, mixed uniformly, nitrogen was introduced, and the temperature was raised to 69°C, then 2.71 g of sodium hydroxide with a molar mass of 40 g / mol was added, and reacted for 4 h, after the reaction was completed, filtration, washing, to obtain a crude product, then the crude product was dissolved in 34 mL of methyl isobutyl ketone, the temperature was raised to 109°C, 1.07 g of polyethylene glycol was added, 10.4 g of 50% liquid alkali was added dropwise, and the reaction was continued for 5 h, after the reaction was completed, washing, removal of solvent, distillation, to obtain intermediate 1;

[0071] (2) 6.45 g of 1,3-dimethyl-6-amino uracil, 4.56 g of intermediate 1 were added to 48 mL of N,N-dimethylformamide solvent, stirred and mixed, reacted at 65°C for 8 h, after the reaction was completed, cooled to room temperature, washed and dried, purified to obtain modified 1,6-dihydroxynaphthalene;

[0072] (3) 0.78 g of graphene oxide was added to 158 mL of deionized water, ultrasonic dispersion for 29 min to obtain a dispersion liquid, 2.53 g of L-glutamic acid was dissolved in 54 mL of 0.1 mol / L sodium hydroxide solution, mechanical stirring for 19 min, after stirring, it was added dropwise to the dispersion liquid, and ultrasonic dispersion was continued for 19 min, stirring at room temperature under nitrogen protection for 25 h, after the reaction was completed, washing, vacuum drying at 49°C, grinding, to obtain modified graphene oxide;

[0073] (4) The polyester fiber clothing waste was recovered, crushed to a length of 0.9 mm to obtain a fiber material, 29.5 mL of ethanol was added to a reactor, the solution pH was adjusted to 3 with glacial acetic acid, then 9.8 mL of γ-aminopropyl triethoxysilane was added, hydrolysis for 13 h, after the hydrolysis was completed, 7.68 g of the fiber material was added, mixed uniformly, and stirred for 11 h, after the reaction was completed, suction filtration, vacuum drying at 104°C for 12 h, to obtain modified fiber;

[0074] (5) 48 parts by weight of epoxy resin, 2 parts by weight of modified fiber, 3 parts by weight of modified graphene oxide, 1.5 parts by weight of modified 1,6-dihydroxynaphthalene, 1.5 parts by weight of carbon black, 2 parts by weight of 2-methyl imidazole, 0.3 parts by weight of leveling agent, 2 parts by weight of barium sulfate were added to a stirrer, high-speed mixing at 380 r / min for 9 min, then the mixed material was put into a twin-screw extruder for melt extrusion, the extrusion temperature was 105°C, after tabletting and cooling, crushing, sieving, to obtain a solid-state conductive powder coating composition.

[0075] Comparative Example 1

[0076] The comparative example 1 provides a solid-state conductive powder coating composition, which is prepared by taking the following raw materials: 40 parts by weight of epoxy resin, 1 part by weight of modified fiber, 2 parts by weight of modified graphene oxide, 1 part by weight of intermediate 1, 1 part by weight of carbon black, 1 part by weight of 2-methylimidazole, 0.2 parts by weight of leveling agent, and 1 part by weight of barium sulfate are added into a blender, mixed at a high speed of 300 r / min for 5 min, and then the mixed materials are put into a twin-screw extruder for melt extrusion at an extrusion temperature of 90°C. After tabletting and cooling, the materials are crushed and sieved to obtain the solid-state conductive powder coating composition.

[0077] The comparative example 1 and the solid-state conductive powder coating composition of example 1 have basically the same composition, and the main difference is that the intermediate 1 obtained in step (1) is used to replace the modified 1,6-dihydroxynaphthalene.

[0078] Comparative example 2

[0079] The comparative example 1 provides a solid-state conductive powder coating composition, which is prepared by taking the following raw materials: 40 parts by weight of epoxy resin, 1 part by weight of modified fiber, 2 parts by weight of modified graphene oxide, 1 part by weight of intermediate 1, 1 part by weight of carbon black, 1 part by weight of 2-methylimidazole, 0.2 parts by weight of leveling agent, and 1 part by weight of barium sulfate are added into a blender, mixed at a high speed of 300 r / min for 5 min, and then the mixed materials are put into a twin-screw extruder for melt extrusion at an extrusion temperature of 90°C. After tabletting and cooling, the materials are crushed and sieved to obtain the solid-state conductive powder coating composition.

[0080] The comparative example 1 and the solid-state conductive powder coating composition of example 1 have basically the same composition, and the main difference is that the intermediate 1 obtained in step (1) is used to replace the modified 1,6-dihydroxynaphthalene.

[0081] Comparative example 3

[0082] The comparative example 1 provides a solid-state conductive powder coating composition, which is prepared by taking the following raw materials: 40 parts by weight of epoxy resin, 1 part by weight of modified fiber, 2 parts by weight of modified graphene oxide, 1 part by weight of intermediate 1, 1 part by weight of carbon black, 1 part by weight of 2-methylimidazole, 0.2 parts by weight of leveling agent, and 1 part by weight of barium sulfate are added into a blender, mixed at a high speed of 300 r / min for 5 min, and then the mixed materials are put into a twin-screw extruder for melt extrusion at an extrusion temperature of 90°C. After tabletting and cooling, the materials are crushed and sieved to obtain the solid-state conductive powder coating composition.

[0083] The comparative example 1 and the solid-state conductive powder coating composition of example 1 have basically the same composition, and the main difference is that the intermediate 1 obtained in step (1) is used to replace the modified 1,6-dihydroxynaphthalene.

[0084] Comparative example 4

[0085] The comparative example 1 provides a solid-state conductive powder coating composition, which is prepared by adding 40 parts by weight of epoxy resin, 1 part by weight of modified fiber, 2 parts by weight of modified graphene oxide, 1 part by weight of modified 1,6-dihydroxynaphthalene, 0.5 part by weight of carbon black, 1 part by weight of 2-methylimidazole, 0.2 part by weight of leveling agent, 1 part by weight of barium sulfate into a blender, mixing at a high speed of 300 r / min for 5 min, then putting the mixed materials into a twin-screw extruder for melt extrusion, the extrusion temperature is 90°C, after tabletting and cooling, crushing, sieving, a solid-state conductive powder coating composition is obtained.

[0086] The solid-state conductive powder coating composition of the comparative example 1 and the example 1 are basically the same in proportion, the main difference is that the weight part of the carbon black is 0.5 parts.

[0087] Performance test:

[0088] The same aluminum plate is selected as the substrate, and the solid-state conductive powder coating compositions prepared in examples 1-5 and comparative examples 1-4 are cured by baking heating, wherein the heating temperature is 200°C and the heating time is 20 min, and the performance of the obtained coating is tested.

[0089] (1) Physical property test: the adhesion of the coating is tested according to GB / T9286-1998; the impact resistance of the coating is tested according to GB / T1732; and the wear resistance of the coating is tested according to GB / T1768-2006 (1 kg, CS10 wheel, 1500 r). The test results are shown in Table 1.

[0090] Table 1: Physical property test

[0091]

[0092]

[0093] It can be seen from Table 1 that the coating obtained by curing the solid-state conductive powder coating compositions prepared in examples 1-5 has good physical properties.

[0094] (2) Conductive property test: the surface resistance of the coating is tested according to GB / T1410-2006. The test results are shown in Table 2.

[0095] Table 2: Conductive property test

[0096]

[0097]

[0098] As can be seen from Table 2, the coating layer obtained by curing the solid conductive powder coating composition prepared in Examples 1-5 has good conductive performance.

[0099] (3) Corrosion resistance test: the corrosion resistance of the coating layer was tested according to GB / T1771, the coating layer was exposed to a neutral salt spray environment formed by atomizing a 5% sodium chloride aqueous solution at a constant temperature of 35±2℃, and after 1000h, the maximum rust width of rust extending from the edge to the inside of the coating layer was tested. The test results are shown in Table 3.

[0100] Table 3: Corrosion resistance test

[0101] Item Maximum width of rust (mm) Example 1 0.6 Example 2 0.5 Example 3 0.6 Example 4 0.6 Example 5 0.5 Comparative Example 1 1.2 Comparative Example 2 1.3 Comparative Example 3 0.8 Comparative Example 4 0.6

[0102] As can be seen from Table 3, the coating layer obtained by curing the solid conductive powder coating composition prepared in Examples 1-5 has good corrosion resistance.

[0103] As can be seen from the comparison, the coating layer obtained in Comparative Example 1 lacks the rigid and polar uracil ring structure, and the multiple polar functional groups on the 1,3-dimethyl-6-amino uracil molecule can form strong hydrogen bonds with the epoxy resin, and this hydrogen bond network can improve the adhesion between the coating layer and the substrate, improve the adhesion of the coating layer in a humid environment, prevent the spread of corrosive media on the coating layer, and the uracil ring can provide lone pair electrons to coordinate with the metal surface to form a protective film, thereby playing a corrosion protection role. Therefore, the physical property data of the coating layer of Comparative Example 1 all decreased, and the maximum rust width significantly increased. The coating layer obtained in Comparative Example 2 lacks L-glutamic acid modification of the graphene oxide, which can cause a decrease in the dispersibility of the graphene oxide and a decrease in the crosslinking density of the epoxy resin. Therefore, the physical property data of the coating layer of Comparative Example 2 all decreased, the surface resistance increased, and the maximum rust width significantly increased. The coating layer obtained in Comparative Example 3 is modified with fiber material, the interfacial adhesion strength of the fiber material and the epoxy resin decreases, and the corrosive medium can penetrate into the surface of the substrate. Therefore, the physical property data of the coating layer of Comparative Example 2 all decreased, and the maximum rust width increased slightly. The coating layer obtained in Comparative Example 4 has a reduced amount of carbon black, which cannot sufficiently fill the gaps of the graphene oxide, resulting in insufficient lapping between the graphene oxide and the surface resistance increasing.

[0104] It should be noted that in this document, the terms “comprising”, “including”, or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or equipment. Without more limitations, the element defined by the statement “comprising a…”, does not exclude the presence of additional identical elements in the process, method, article or equipment including the element.

[0105] The above examples are only used to illustrate the technical solutions of the present application, but not to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

[0106] Those skilled in the art should understand that the above only describes several specific embodiments of the present application, but not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications and improvements that do not exceed the scope of the claims should be considered as the protection scope of the present application.

Claims

1. A method for preparing a solid conductive powder coating composition, characterized in that, Includes the following steps: (1) Add 1,6-dihydroxynaphthalene, epichlorohydrin, tetramethylammonium bromide and sodium hydroxide to the reactor, react to obtain crude product, then dissolve the crude product in methyl isobutyl ketone, add polyethylene glycol and 50% liquid alkali, react to obtain intermediate 1; (2) Add 1,3-dimethyl-6-aminourea pyrimidine and intermediate 1 to N,N-dimethylformamide solvent, stir and react to obtain modified 1,6-dihydroxynaphthalene; (3) Add graphene oxide to deionized water, disperse it by ultrasonication, add L-glutamic acid dropwise to the dispersion, and react to obtain modified graphene oxide. (4) Recycle polyester fiber clothing waste to obtain fiber material, add γ-aminopropyltriethoxysilane, hydrolyze, and react to obtain modified fiber; (5) Add epoxy resin, modified fiber, modified graphene oxide, modified 1,6-dihydroxynaphthalene, carbon black, 2-methylimidazole, leveling agent and barium sulfate into a mixer and mix at high speed of 300-400 r / min for 5-10 min. Then put the mixed material into a twin-screw extruder for melt extrusion, press and cool, crush and sieve to obtain a solid conductive powder coating composition.

2. The method for preparing the solid conductive powder coating composition according to claim 1, characterized in that, In step (1), 4.48-4.52g of 1,6-dihydroxynaphthalene, 51.8-51.9g of epichlorohydrin, and 0.06-0.07g of tetramethylammonium bromide are added to the reactor, mixed evenly, nitrogen gas is introduced, and the temperature is raised to 65-70℃. Then, 2.68-2.72g of sodium hydroxide with a molar mass of 40g / mol is added, and the reaction is carried out for 2-4h. After the reaction is completed, the mixture is filtered, washed, and the crude product is obtained. The crude product is then dissolved in 30-35mL of methyl isobutyl ketone, the temperature is raised to 105-100℃, 1.04-1.08g of polyethylene glycol is added, and 10-10.5g of 50% liquid alkali is added dropwise. The reaction is continued for 3-5h. After the reaction is completed, the mixture is washed, the solvent is removed, and the mixture is distilled to obtain intermediate 1.

3. The method for preparing the solid conductive powder coating composition according to claim 1, characterized in that, In step (2), 6.42-6.46 g of 1,3-dimethyl-6-aminourea pyrimidine and 4.53-4.57 g of intermediate 1 are added to 40-50 mL of N,N-dimethylformamide solvent, stirred and mixed, and reacted at 50-70 °C for 6-8 h. After the reaction is completed, the mixture is cooled to room temperature, washed and dried, and purified to obtain modified 1,6-dihydroxynaphthalene.

4. The method for preparing the solid conductive powder coating composition according to claim 1, characterized in that, In step (3), 0.7-0.8 g of graphene oxide is added to 155-160 mL of deionized water and ultrasonically dispersed for 25-30 min to obtain a dispersion. 2.5-2.54 g of L-glutamic acid is dissolved in 50-55 mL of 0.1 mol / L sodium hydroxide solution and mechanically stirred for 15-20 min. After stirring, the solution is added dropwise to the dispersion and ultrasonically dispersed for another 15-20 min. The mixture is stirred for 22-26 h at room temperature under nitrogen protection. After the reaction is complete, the mixture is washed, vacuum dried at 45-50 °C, and ground to obtain modified graphene oxide.

5. The method for preparing the solid conductive powder coating composition according to claim 1, characterized in that, In step (4), waste polyester fiber clothing is recycled, crushed to a length of 0.5-1 mm to obtain fiber material, 28-30 mL of ethanol is added to the reactor, the pH of the solution is adjusted with glacial acetic acid, and then 9-10 mL of γ-aminopropyltriethoxysilane is added. Hydrolysis is carried out for 10-14 h. After hydrolysis, 7.6-7.7 g of fiber material is added, mixed evenly, and stirred for 8-12 h. After the reaction is completed, the mixture is filtered and vacuum dried at 100-105 °C for 10-12 h to obtain modified fiber.

6. The method for preparing the solid conductive powder coating composition according to claim 1, characterized in that, The weight parts of each component in step (5) are as follows: 40-50 parts epoxy resin, 1-3 parts modified fiber, 2-3 parts modified graphene oxide, 1-1.5 parts modified 1,6-dihydroxynaphthalene, 1-1.5 parts carbon black, 1-2 parts 2-methylimidazole, 0.2-0.3 parts leveling agent, and 1-3 parts barium sulfate.

7. The method for preparing the solid conductive powder coating composition according to claim 1, characterized in that, The extrusion temperature in step (5) is 90-110℃.

8. A solid conductive powder coating composition, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.

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