Modified carbon black for coating and preparation method thereof

Abstract

The invention relates to the technical field of nano carbon black modification, in particular to modified carbon black for a coating and a preparation method of the modified carbon black, and the modified carbon black comprises the following raw materials in parts by mass: 8-10.4 parts of carbon black particles; 29 to 36 parts of a modified carbon black compound; 13 to 16.2 parts of resin; 63-77 parts of an organic solvent; 3.4 to 5 parts of a wetting agent; 3.8 to 5.6 parts of a dispersant; wherein the modified beta-cyclodextrin in the modified carbon black compound is prepared by the following steps: aminating beta-cyclodextrin, combining the aminated beta-cyclodextrin with ascorbic acid, and compounding the aminated beta-cyclodextrin with carbon black particles subjected to ozonization and acylating chlorination, so as to obtain the modified carbon black compound taking the modified beta-cyclodextrin as a carrier; the modified beta-cyclodextrin can effectively improve the dispersity and stability of the carbon black in the coating, and then the modified beta-cyclodextrin is mixed with the solvent, the resin and other auxiliaries to obtain the modified carbon black with ultraviolet shielding performance and corrosion resistance, and the modified carbon black has wide application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of nano carbon black modification, in particular to modified carbon black for coatings and a preparation method thereof. Background Art

[0002] Carbon black, also known as carbon black, is a light, loose and extremely fine black powder with a very large specific surface area. It is the product of incomplete combustion or thermal decomposition of carbon-containing substances (coal, natural gas, fuel oil, etc.) under insufficient air conditions. Its particles are approximately spherical and can be fused or agglomerated to form three-dimensional bonded dendritic or fibrous aggregates. The main component of carbon black is carbon, and it is the earliest nanomaterial developed and applied by humans.

[0003] Carbon black is mainly divided into pigment carbon black, rubber carbon black and conductive carbon black according to its use. They are widely used in many industrial fields such as rubber, ink, coating, plastic, electronic components, etc., and are one of the most important industrial raw materials in today's life and production. They are widely used in the reinforcement of rubber, especially the tire industry, anti-aging and antistatic of plastic products, lithium battery negative electrode materials, catalyst carriers, printing and dyeing, and biosensors.

[0004] Paint is a general term for liquid or solid materials used to coat surfaces, forming a continuous, firmly adhered protective film or coating. Paint typically consists of a film-forming substance (such as a resin, emulsion, or drying oil), pigments, fillers, solvents, and additives. The film-forming substance is the core component of the paint and determines its basic properties. Pigments and fillers impart color and hiding power to the paint. Solvents dilute the paint and aid application. Additives, such as carbon black, improve its performance.

[0005] In the prior art, patent document CN114989657B discloses a method for preparing modified carbon black for mildew-proof coatings. By attaching a ZnO film layer to the surface of nano-carbon black, the carbon black has a photocatalytic effect. When added to the coating, it has mildew-proof and bactericidal effects, and the photodissolution of ZnO can be effectively inhibited by the action of the coating liquid. The modified carbon black prepared in this invention has a good mildew-proof effect, and the coating liquid can also further extend the action time of the coating, but the anti-ultraviolet performance needs to be further improved.

[0006] Therefore, according to the above-mentioned related technologies, there is an urgent need to develop a modified carbon black for coatings and a preparation method thereof. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a modified carbon black for coatings and a preparation method thereof, so as to solve the problems of poor mildew resistance and UV resistance of carbon black in coatings in the prior art.

[0008] Based on the above objectives, the present invention provides a modified carbon black for coatings and a preparation method thereof.

[0009] A modified carbon black for coatings, comprising the following raw materials in parts by weight:

[0010] 8-10.4 parts of carbon black particles; 29-36 parts of modified carbon black compound; 13-16.2 parts of resin; 63-77 parts of organic solvent; 3.4-5 parts of wetting agent; 3.8-5.6 parts of dispersant;

[0011] The modified carbon black composite is prepared from modified β-cyclodextrin and carbon black particles;

[0012] The modified β-cyclodextrin is prepared from β-cyclodextrin, 3-aminopropyltriethoxysilane and ascorbic acid;

[0013] The carbon black particles are produced by thermal cracking of natural gas and oil products, have a carbon content of ≥98.5%, and a particle size of 100-180 nm.

[0014] Preferably, the preparation method of the modified carbon black composite is as follows:

[0015] Step A1. β-cyclodextrin was added to an ethanol-water solution and ultrasonically dispersed. 3-aminopropyltriethoxysilane was then added dropwise to the dispersion. The mixture was heated to reflux. The resulting product was allowed to stand, the supernatant removed, and the mixture was washed with ethanol 2-3 times. The mixture was then dried at 70-80°C for 20-22 hours to obtain amino-β-cyclodextrin.

[0016] Step A2. Adding amino β-cyclodextrin and ascorbic acid to N,N-dimethylformamide, stirring evenly, then adding N,N′-dicyclohexylcarbodiimide, heating to reflux, filtering, and washing with deionized water to obtain modified β-cyclodextrin;

[0017] Step A3. Add carbon black particles to an oxidation device containing zirconium beads, add deionized water and stir evenly, introduce ozone while stirring to perform a first ozone oxidation, then adjust the pH of the system to 13-14 with saturated sodium hydroxide, perform a second ozone oxidation, and then adjust the pH to 3-4 with concentrated hydrochloric acid. Centrifuge, wash with deionized water, and separate to obtain ozonated carbon black.

[0018] Step A4. Add ozonated carbon black to a round-bottom flask, then add dichloromethane to the flask, and add thionyl chloride thereto under nitrogen protection, heat to react, rotary evaporation, then add N,N-dimethylformamide, and dropwise add modified β-cyclodextrin solution under nitrogen protection, heat to reflux, cool to room temperature and filter, then use N,N-dimethylformamide, anhydrous ethanol, and deionized water to wash in sequence until the filtrate is clear and transparent, dry to constant weight, and obtain a modified carbon black composite.

[0019] Preferably, the dosage ratio of β-cyclodextrin, ethanol aqueous solution and 3-aminopropyltriethoxysilane in step A1 is 0.4-0.5 g:30-40 mL:0.8-1.5 g, and the volume ratio of ethanol to water in the ethanol aqueous solution is 13-16:2-4;

[0020] The frequency of the ultrasonic dispersion is 16-18 kHz and the temperature is 20-30° C., the temperature during the heating reflux is 45-65° C. and the heating time is 11-13 h.

[0021] Preferably, the amount ratio of N,N-dimethylformamide, amino-β-cyclodextrin, ascorbic acid and N,N′-cyclohexylcarbodiimide in step A2 is 40-50 mL: 10.2-12.5 g: 2.3-2.7 g: 0.1-0.16 g;

[0022] The temperature during the heating reflux is 75-82° C. and the time is 5.5-7 h.

[0023] Preferably, the mass ratio of the carbon black particles to deionized water in step A3 is 3.8-4.4:65-80;

[0024] The ozone flow rate during the first ozone oxidation is 1.5-2.5 L / min and the oxidation time is 1-1.5 h;

[0025] During the second ozone oxidation, the flow rate of ozone is 2.5-3 L / min, and the oxidation time is 6.5-7.5 h.

[0026] Preferably, in step A4, the ratio of the amount of ozonated carbon black to dichloromethane, thionyl chloride, N,N-dimethylformamide and modified β-cyclodextrin solution is 3.2-4 g: 12-15 mL: 5.5-7 mL: 28-33 mL: 70-76 mL.

[0027] Preferably, the modified β-cyclodextrin solution in step A4 is obtained by mixing modified β-cyclodextrin and N,N-dimethylformamide in a ratio of 10-15 g: 34-49 mL;

[0028] The temperature during the heating reaction is 40-50°C and the reaction time is 1-1.5h;

[0029] The temperature during the heating reflux is 55-62° C., and the reaction time is 4.5-5.5 h.

[0030] Preferably, the solvent is any one of xylene, acetone, methyl pyruvate, propanol, and naphtha;

[0031] The resin is at least one of phenolic resin, epoxy resin and polyacrylic resin.

[0032] Preferably, the wetting agent is at least one of triethyl phosphate, dimethyl phosphate, and octanolamine;

[0033] The dispersant is any one of polybutyl acrylate, polyisobutyl acrylate, polyvinyl ester and polyvinyl ester.

[0034] A method for preparing modified carbon black for coatings comprises the following steps:

[0035] Add the modified carbon black compound, wetting agent and dispersant to the solvent, stir at a speed of 140-180 rpm for 20-25 minutes, then add carbon black particles and resin and stir for 8-11 minutes to obtain modified carbon black.

[0036] Beneficial effects of the present invention:

[0037] The present invention provides a modified carbon black for coatings and a preparation method thereof. The present invention obtains a modified carbon black with ultraviolet shielding and corrosion resistance by mixing carbon black particles with a modified carbon black compound, a resin, a wetting agent, a dispersant and a solvent. The modified β-cyclodextrin in the modified carbon black compound is prepared by combining the β-cyclodextrin with ascorbic acid after amination, and then compounding the modified carbon black particles with ozonation and chlorination to obtain a modified carbon black compound with the modified β-cyclodextrin as a carrier. The ascorbic acid itself has antioxidant and light-proof properties, which further improves the stability, corrosion resistance and overall ultraviolet resistance of the aminated β-cyclodextrin. The dispersibility of the modified carbon black particles in the coating is improved, and thus the ultraviolet shielding performance thereof is further improved. The modified β-cyclodextrin provides a relatively stable environment for the carbon black particles. Compared with the prior art, the modified carbon black compound has broad application prospects. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0039] The sources and properties of some of the raw materials used in the present invention are as follows:

[0040] APTES was purchased from Hangzhou Jessica Chemical Co., Ltd.; ρ-cyclodextrin was purchased from Nanjing Bermuda Biotechnology Co., Ltd.; N,N-dimethylformamide was purchased from Aladdin Co., Ltd.; ascorbic acid was purchased from Shanghai Yuanye Biotechnology Co., Ltd.; N,N′-dicyclohexylcarbodiimide was purchased from Beijing Biolab Technology Co., Ltd.; and thionyl chloride was purchased from Jinan Century Tongda Chemical Co., Ltd.

[0041] Example 1: A method for preparing modified carbon black for coatings, comprising the following steps:

[0042] S1. Add 0.4 g of β-cyclodextrin to 30 mL of ethanol-water solution (volume ratio of ethanol to water is 13:2). Ultrasonic dispersion is performed at 16 kHz and 20°C. Then, 0.8 g of 3-aminopropyltriethoxysilane is added dropwise to the dispersion. The mixture is heated under reflux at 45°C for 11 h. The resulting product is allowed to stand, the supernatant removed, and the product is washed twice with ethanol. The product is then dried at 70°C for 20 h to obtain amino-β-cyclodextrin.

[0043] S2. To 40 mL of N,N-dimethylformamide, 10.2 g of amino-modified β-cyclodextrin and 2.3 g of ascorbic acid were added, stirred, and then 0.1 g of N,N′-dicyclohexylcarbodiimide was added. The mixture was heated at reflux at 75°C for 5.5 h, filtered, and washed with deionized water to obtain modified β-cyclodextrin.

[0044] S3. 3.8 g of carbon black particles were added to an oxidation device containing zirconium beads, 65 g of deionized water was added and stirred, and ozone was introduced while stirring. The ozone flow rate was 1.5 L / min and the oxidation time was 1 h. The first ozone oxidation was performed, and then the pH value of the system was easily adjusted to 13 with saturated sodium hydroxide. The second ozone oxidation was performed at an ozone flow rate of 2.5 L / min and the oxidation time was 6.5 h. The pH was then adjusted to 3 with concentrated hydrochloric acid, centrifuged, washed with deionized water, and separated to obtain ozonated carbon black;

[0045] S4. Add 3.2 g of ozonated carbon black to a round-bottom flask, then add 12 mL of dichloromethane to the flask, and under nitrogen protection, add 5.5 mL of thionyl chloride. Heat the reaction at 40°C for 1 h, rotary evaporate, add 28 mL of N,N-dimethylformamide, and dropwise add 70 mL of modified β-cyclodextrin solution under nitrogen protection, wherein the ratio of modified β-cyclodextrin to N,N-dimethylformamide is 10 g:34 mL. Heat and reflux at 55°C for 4.5 h, cool to room temperature, filter, and then wash with N,N-dimethylformamide, anhydrous ethanol, and deionized water in sequence until the filtrate is clear and transparent. Dry and weigh to obtain a modified carbon black composite.

[0046] S5. To 63 g of xylene, 29 g of a modified carbon black composite, 3.4 g of triethyl phosphate, and 3.8 g of polybutyl acrylate were added, and the mixture was stirred at 140 rpm for 20 min. Then, 8 g of carbon black particles and 13 g of phenolic resin were added and stirred for 8 min to obtain modified carbon black.

[0047] Example 2: A method for preparing modified carbon black for coatings, comprising the following steps:

[0048] S1. Add 0.42 g of β-cyclodextrin to 32 mL of ethanol-water solution (volume ratio of ethanol to water is 14:2). Ultrasonic dispersion is performed at 16 kHz and 22°C. Then, 0.9 g of 3-aminopropyltriethoxysilane is added dropwise to the dispersion. The mixture is heated under reflux at 47°C for 11.5 h. The resulting product is allowed to stand, the supernatant removed, and the mixture is washed with ethanol 2-3 times. The mixture is then dried at 72°C for 20.5 h to obtain amino-β-cyclodextrin.

[0049] S2. To 42 mL of N,N-dimethylformamide, 10.5 g of amino-modified β-cyclodextrin and 2.4 g of ascorbic acid were added and stirred. 0.11 g of N,N′-dicyclohexylcarbodiimide was then added and heated under reflux at 77°C for 6 h. The mixture was filtered and washed with deionized water to obtain modified β-cyclodextrin.

[0050] S3. 3.9 g of carbon black particles were added to an oxidation device containing zirconium beads, 68 g of deionized water was added and stirred, and ozone was introduced while stirring. The ozone flow rate was 1.7 L / min and the oxidation time was 1 h. The first ozone oxidation was performed, and then the pH value of the system was easily adjusted to 13 with saturated sodium hydroxide. The ozone flow rate was 2.6 L / min and the oxidation time was 6.5 h. The second ozone oxidation was performed, and the pH was adjusted to 3 with concentrated hydrochloric acid. The mixture was centrifuged, washed with deionized water, and separated to obtain ozonated carbon black.

[0051] S4. Add 3.4 g of ozonated carbon black to a round-bottom flask, then add 13 mL of dichloromethane to the flask, and add 5.7 mL of thionyl chloride under nitrogen protection. Heat the reaction at 42°C for 1 h, rotary evaporate, add 29 mL of N,N-dimethylformamide, and dropwise add 71 mL of modified β-cyclodextrin solution under nitrogen protection, wherein the ratio of modified β-cyclodextrin to N,N-dimethylformamide is 12 g:34 mL. Heat and reflux at 57°C for 4.5 h, cool to room temperature, filter, and wash with N,N-dimethylformamide, anhydrous ethanol, and deionized water in sequence until the filtrate is clear and transparent. Dry and weigh to obtain a modified carbon black composite.

[0052] S5. To 66 g of acetone, 30 g of a modified carbon black composite, 3.8 g of dimethyl phosphate, and 4.3 g of polyisobutyl acrylate were added, and the mixture was stirred at 150 rpm for 21 min. 8.4 g of carbon black particles and 13.5 g of epoxy resin were then added and stirred for 9 min to obtain modified carbon black.

[0053] Example 3: A method for preparing modified carbon black for coatings, comprising the following steps:

[0054] S1. Add 0.44 g of β-cyclodextrin to 34 mL of ethanol-water solution (volume ratio of ethanol to water is 15:3). Ultrasonic dispersion is performed at 17 kHz and 24°C. Then, 1 g of 3-aminopropyltriethoxysilane is added dropwise to the dispersion. The mixture is heated under reflux at 50°C for 12 h. The resulting product is allowed to stand, the supernatant removed, and the mixture is washed with ethanol 2-3 times. The mixture is then dried at 74°C for 21 h to obtain amino-β-cyclodextrin.

[0055] S2. To 44 mL of N,N-dimethylformamide, 10.8 g of amino-modified β-cyclodextrin and 2.5 g of ascorbic acid were added, stirred, and then 0.12 g of N,N'-dicyclohexylcarbodiimide was added. The mixture was heated under reflux at 79 ° C for 6 h, filtered, and washed with deionized water to obtain modified β-cyclodextrin.

[0056] S3. 4 g of carbon black particles were added to an oxidation device containing zirconium beads, 69 g of deionized water was added and stirred, and ozone was introduced while stirring. The ozone flow rate was 1.7 L / min and the oxidation time was 1 h. The first ozone oxidation was performed, and then the pH value of the system was easily adjusted to 14 with saturated sodium hydroxide. The ozone flow rate was 2.7 L / min and the oxidation time was 7 h. The second ozone oxidation was performed, and the pH was adjusted to 4 with concentrated hydrochloric acid. The mixture was centrifuged, washed with deionized water, and separated to obtain ozonated carbon black.

[0057] S4. Add 3.5 g of ozonated carbon black to a round-bottom flask, then add 13 mL of dichloromethane to the flask, and under nitrogen protection, add 6 mL of thionyl chloride. Heat the reaction at 44°C for 1 h, rotary evaporate, add 30 mL of N,N-dimethylformamide, and dropwise add 73 mL of modified β-cyclodextrin solution under nitrogen protection, wherein the ratio of modified β-cyclodextrin to N,N-dimethylformamide is 14 g:39 mL. Heat and reflux at 60°C for 5 h, cool to room temperature, filter, and then wash with N,N-dimethylformamide, anhydrous ethanol, and deionized water in sequence until the filtrate is clear and transparent. Dry and weigh to obtain a modified carbon black composite.

[0058] S5. To 69 g of methyl pyruvate, 32 g of a modified carbon black composite, 4 g of octanolamine, and 4.4 g of polyethylene ester were added, stirred at 160 rpm for 23 min, and then 8.8 g of carbon black particles and 14 g of polyacrylic acid resin were added and stirred for 10 min to obtain modified carbon black.

[0059] Example 4: A method for preparing modified carbon black for coatings, comprising the following steps:

[0060] S1. Add 0.46 g of β-cyclodextrin to 36 mL of ethanol-water solution (volume ratio of ethanol to water is 15:3). Ultrasonic dispersion is performed at 17 kHz and 26°C. Then, 1.2 g of 3-aminopropyltriethoxysilane is added dropwise to the dispersion. The mixture is heated under reflux at 61°C for 12.5 h. The resulting product is allowed to stand, the supernatant removed, and the product is washed with ethanol 2-3 times. The product is then dried at 76°C for 21.5 h to obtain amino-β-cyclodextrin.

[0061] S2. To 46 mL of N,N-dimethylformamide, 11.5 g of amino-modified β-cyclodextrin and 2.5 g of ascorbic acid were added and stirred. 0.14 g of N,N′-dicyclohexylcarbodiimide was then added and heated under reflux at 80°C for 6.5 h. The mixture was filtered and washed with deionized water to obtain modified β-cyclodextrin.

[0062] S3. 4.2 g of carbon black particles were added to an oxidation device containing zirconium beads, 74 g of deionized water was added and stirred, and ozone was introduced while stirring. The ozone flow rate was 2.1 L / min and the oxidation time was 1.5 h. The first ozone oxidation was performed, and then the pH value of the system was easily adjusted to 14 with saturated sodium hydroxide. The ozone flow rate was 2.7 L / min and the oxidation time was 7 h. The second ozone oxidation was performed, and the pH was adjusted to 4 with concentrated hydrochloric acid. The mixture was centrifuged, washed with deionized water, and separated to obtain ozonated carbon black.

[0063] S4. 3.7 g of ozonated carbon black was added to a round-bottom flask, followed by 14 mL of dichloromethane and 6.4 mL of thionyl chloride under nitrogen protection. The mixture was heated at 46°C for 1.5 h, and then evaporation was performed. 32 mL of N,N-dimethylformamide was added, and 75 mL of a modified β-cyclodextrin solution was added dropwise under nitrogen protection. The modified β-cyclodextrin and N,N-dimethylformamide were used in a ratio of 14 g:43 mL. The mixture was heated under reflux at 60°C for 5 h, cooled to room temperature, filtered, and washed with N,N-dimethylformamide, anhydrous ethanol, and deionized water in sequence until the filtrate was clear and transparent. The filtrate was dried to a constant weight to obtain a modified carbon black composite.

[0064] S5. To 72 g of xylene, 34 g of a modified carbon black composite, 4.6 g of triethyl phosphate, and 4.8 g of polybutyl acrylate were added, and the mixture was stirred at 160 rpm for 24 min. Then, 9.4 g of carbon black particles and 15.4 g of phenolic resin were added and stirred for 10 min to obtain modified carbon black.

[0065] Example 5: A method for preparing modified carbon black for coatings, comprising the following steps:

[0066] S1. Add 0.48 g of β-cyclodextrin to 38 mL of ethanol-water solution (volume ratio of ethanol to water is 16:3). Ultrasonic dispersion is performed at 17 kHz and 28°C. Then, 1.4 g of 3-aminopropyltriethoxysilane is added dropwise to the dispersion. The mixture is heated under reflux at 63°C for 12.5 h. The resulting product is allowed to stand, the supernatant removed, and the product is washed with ethanol 2-3 times. The product is then dried at 78°C for 21.5 h to obtain amino-β-cyclodextrin.

[0067] S2. To 48 mL of N,N-dimethylformamide, 12 g of amino-modified β-cyclodextrin and 2.6 g of ascorbic acid were added and stirred. 0.15 g of N,N′-dicyclohexylcarbodiimide was then added and heated under reflux at 80°C for 6.5 h. The mixture was filtered and washed with deionized water to obtain modified β-cyclodextrin.

[0068] S3. 4.2 g of carbon black particles were added to an oxidation device containing zirconium beads, 77 g of deionized water was added and stirred, and ozone was introduced while stirring. The ozone flow rate was 2.5 L / min and the oxidation time was 1.5 h. The first ozone oxidation was performed, and then the pH value of the system was easily adjusted to 14 with saturated sodium hydroxide. The ozone flow rate was 2.9 L / min and the oxidation time was 7.5 h. The second ozone oxidation was performed, and the pH was adjusted to 4 with concentrated hydrochloric acid. The mixture was centrifuged, washed with deionized water, and separated to obtain ozonated carbon black.

[0069] S4. 3.9 g of ozonated carbon black was added to a round-bottom flask, followed by 14 mL of dichloromethane and 6.7 mL of thionyl chloride under nitrogen protection. The mixture was heated at 48°C for 1.5 h, and then evaporation was performed. 31 mL of N,N-dimethylformamide was added, and 75 mL of a modified β-cyclodextrin solution was added dropwise under nitrogen protection. The modified β-cyclodextrin and N,N-dimethylformamide were used in a ratio of 14 g:45 mL. The mixture was heated under reflux at 61°C for 5.5 h, cooled to room temperature, filtered, and washed with N,N-dimethylformamide, anhydrous ethanol, and deionized water in sequence until the filtrate was clear and transparent. The filtrate was dried to a constant weight to obtain a modified carbon black composite.

[0070] S5. To 75 g of naphtha, 35 g of modified carbon black composite, 4.7 g of triethyl phosphate and 5.3 g of polybutyl acrylate were added, stirred at a speed of 170 rpm for 24 min, and then 10 g of carbon black particles and 15.8 g of phenolic resin were added and stirred for 10 min to obtain modified carbon black.

[0071] Example 6: A method for preparing modified carbon black for coatings, comprising the following steps:

[0072] S1. Add 0.5 g of β-cyclodextrin to 40 mL of ethanol-water solution (volume ratio of ethanol to water is 16:4). Ultrasonic dispersion is performed at 18 kHz and 30°C. Then, 1.5 g of 3-aminopropyltriethoxysilane is added dropwise to the dispersion. The mixture is heated under reflux at 65°C for 13 h. The resulting product is allowed to stand, the supernatant removed, and the product is washed with ethanol 2-3 times. The product is then dried at 80°C for 22 h to obtain amino-β-cyclodextrin.

[0073] S2. To 50 mL of N,N-dimethylformamide, 12.5 g of amino-modified β-cyclodextrin and 2.7 g of ascorbic acid were added and stirred. 0.16 g of N,N′-dicyclohexylcarbodiimide was then added and heated under reflux at 82°C for 7 h. The mixture was filtered and washed with deionized water to obtain modified β-cyclodextrin.

[0074] S3. 4.4 g of carbon black particles were added to an oxidation device containing zirconium beads, 80 g of deionized water was added and stirred, and ozone was introduced while stirring. The ozone flow rate was 2.5 L / min and the oxidation time was 1.5 h. The first ozone oxidation was performed, and then the pH value of the system was easily adjusted to 14 with saturated sodium hydroxide. The ozone flow rate was 3 L / min and the oxidation time was 7.5 h. The second ozone oxidation was performed, and the pH was adjusted to 4 with concentrated hydrochloric acid. The mixture was centrifuged, washed with deionized water, and separated to obtain ozonated carbon black.

[0075] S4. 4 g of ozonated carbon black was added to a round-bottom flask, followed by 15 mL of dichloromethane and 7 mL of thionyl chloride under nitrogen protection. The mixture was heated at 50°C for 1.5 h, and then evaporation was performed. 33 mL of N,N-dimethylformamide was added, and 76 mL of a modified β-cyclodextrin solution (the ratio of modified β-cyclodextrin to N,N-dimethylformamide was 15 g:49 mL) was added dropwise under nitrogen protection. The mixture was heated under reflux at 62°C for 5.5 h, cooled to room temperature, filtered, and washed with N,N-dimethylformamide, anhydrous ethanol, and deionized water in sequence until the filtrate was clear and transparent. The filtrate was dried to a constant weight to obtain a modified carbon black composite.

[0076] S5. To 77 g of xylene, 36 g of a modified carbon black composite, 5 g of triethyl phosphate, and 5.6 g of polybutyl acrylate were added, and the mixture was stirred at 180 rpm for 25 min. Then, 10.4 g of carbon black particles and 16.2 g of a phenolic resin were added and stirred for 11 min to obtain modified carbon black.

[0077] Comparative Example 1:

[0078] Compared with Example 1, this comparative example did not add the modified carbon black composite during the preparation of carbon black. The remaining steps and parameters were the same and will not be repeated in this comparative example. Finally, carbon black was obtained.

[0079] Comparative Example 2:

[0080] Compared with Example 1, this comparative example only replaces "modified β-cyclodextrin" with "amino-β-cyclodextrin", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally carbon black is obtained.

[0081] Comparative Example 3:

[0082] Compared with Example 1, this comparative example only replaces "modified β-cyclodextrin" with "β-cyclodextrin", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally carbon black is obtained.

[0083] Comparative Example 4:

[0084] Compared with Example 1, this comparative example only replaces "29g modified carbon black composite, 8g carbon black particles" with "8g modified carbon black composite, 29g carbon black particles", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally carbon black is obtained.

[0085] Comparative Example 5:

[0086] Compared with Example 1, this comparative example only replaces "29g modified carbon black composite, 8g carbon black particles" with "29g modified carbon black composite, 29g carbon black particles", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and carbon black is finally obtained.

[0087] Performance testing:

[0088] Mildew resistance:

[0089] A water-based varnish was prepared using Koning 709Y water-based thermosetting acrylic resin, and 5% by mass of the modified carbon black prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were added respectively. A film was formed using a 20 μm film-making device. After curing, Staphylococcus aureus was used as the test object according to the test method of GB / T31402-2015 "Test method for antibacterial properties of plastic surfaces". The surface of the coating was inoculated with Staphylococcus aureus, sprayed with water three times a day, and illuminated with a xenon lamp for 12 hours a day. After 30 days, the number of viable bacteria (CFU / cm2) on the surface of the coating was detected.

[0090] UV resistance:

[0091] The modified carbon blacks prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were placed in an ultraviolet absorption spectrometer, and their anti-ultraviolet performance was evaluated by analyzing their ultraviolet absorption spectra. Generally, the higher the absorbance, the stronger the color paste's ability to absorb ultraviolet rays, and thus has better anti-ultraviolet performance.

[0092] Table 1

[0093]

[0094]

[0095] Data Analysis:

[0096] As can be seen from Table 1, the carbon black prepared by the present invention has better mildew resistance and UV resistance. This may be because the modified carbon black in the present invention is obtained by mixing carbon black particles with modified carbon black composites, resins, wetting agents, dispersants and solvents. Carbon black is a nanoparticle with UV shielding properties, but due to its high specific surface area and strong adsorption, it is very easy for molecules to agglomerate, resulting in poor dispersibility in the coating and large differences in UV resistance in different areas. The present invention improves the UV resistance of carbon black by mixing carbon black with modified carbon black composites and other additives. Linear performance; the modified carbon black composite is prepared from modified β-cyclodextrin and carbon black particles. After the ascorbic acid with antioxidant and light-proof properties is combined with amino-β-cyclodextrin, the modified β-cyclodextrin carrier obtained provides a relatively stable environment for the carbon black particles and improves their dispersibility in the coating. At the same time, the two synergistically exert anti-ultraviolet properties and have certain anti-corrosion and antibacterial properties; the small amount of carbon black contained in the modified carbon black can immediately play a UV shielding role in the coating, and the modified carbon black composite can effectively prolong the action time of the carbon black particles, playing a synergistic role in preventing the aging of the coating.

[0097] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0098] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A modified carbon black for coatings, characterized in that: Including the following raw materials by weight: 8-10.4 parts of carbon black particles; 29-36 parts of modified carbon black compound; 13-16.2 parts of resin; 63-77 parts of organic solvent; 3.4-5 parts of wetting agent; 3.8-5.6 parts of dispersant; The modified carbon black composite is prepared from modified β-cyclodextrin and carbon black particles; The modified β-cyclodextrin is prepared from β-cyclodextrin, 3-aminopropyltriethoxysilane and ascorbic acid; The carbon black particles are produced by thermal cracking of natural gas and oil products, have a carbon content of ≥98.5%, and a particle size of 100-180 nm.

2. The modified carbon black for coating according to claim 1, characterized in that The preparation method of the modified carbon black composite is as follows: Step A1. β-cyclodextrin was added to an ethanol-water solution and ultrasonically dispersed. 3-aminopropyltriethoxysilane was then added dropwise to the dispersion. The mixture was heated to reflux. The resulting product was allowed to stand, the supernatant removed, and the mixture was washed with ethanol 2-3 times. The mixture was then dried at 70-80°C for 20-22 hours to obtain amino-β-cyclodextrin. Step A2. Adding amino β-cyclodextrin and ascorbic acid to N,N-dimethylformamide, stirring evenly, then adding N,N′-dicyclohexylcarbodiimide, heating to reflux, filtering, and washing with deionized water to obtain modified β-cyclodextrin; Step A3. Add carbon black particles to an oxidation device containing zirconium beads, add deionized water and stir evenly, introduce ozone while stirring to perform a first ozone oxidation, then adjust the pH of the system to 13-14 with saturated sodium hydroxide, perform a second ozone oxidation, and then adjust the pH to 3-4 with concentrated hydrochloric acid. Centrifuge, wash with deionized water, and separate to obtain ozonated carbon black. Step A4. Add ozonated carbon black to a round-bottom flask, then add dichloromethane to the flask, and add thionyl chloride thereto under nitrogen protection, heat to react, rotary evaporation, then add N,N-dimethylformamide, and dropwise add modified β-cyclodextrin solution under nitrogen protection, heat to reflux, cool to room temperature and filter, then use N,N-dimethylformamide, anhydrous ethanol, and deionized water to wash in sequence until the filtrate is clear and transparent, dry to constant weight, and obtain a modified carbon black composite.

3. The modified carbon black for coating according to claim 2, characterized in that The amount ratio of β-cyclodextrin, ethanol aqueous solution and 3-aminopropyltriethoxysilane in step A1 is 0.4-0.5 g:30-40 mL:0.8-1.5 g, and the volume ratio of ethanol to water in the ethanol aqueous solution is 13-16:2-4; The frequency of the ultrasonic dispersion is 16-18 kHz and the temperature is 20-30° C., the temperature during the heating reflux is 45-65° C. and the heating time is 11-13 h.

4. The modified carbon black for coating according to claim 2, characterized in that The ratio of N,N-dimethylformamide, amino-β-cyclodextrin, ascorbic acid and N,N′-dicyclohexylcarbodiimide used in step A2 is 40-50 mL: 10.2-12.5 g: 2.3-2.7 g: 0.1-0.16 g; The temperature during the heating reflux is 75-82° C. and the time is 5.5-7 h.

5. The modified carbon black for coating according to claim 2, characterized in that In step A3, the mass ratio of carbon black particles to deionized water is 3.8-4.4:65-80; The ozone flow rate during the first ozone oxidation is 1.5-2.5 L / min and the oxidation time is 1-1.5 h; During the second ozone oxidation, the flow rate of ozone is 2.5-3 L / min, and the oxidation time is 6.5-7.5 h.

6. The modified carbon black for coatings according to claim 2, characterized in that In step A4, the ratio of ozonated carbon black to dichloromethane, thionyl chloride, N,N-dimethylformamide and modified β-cyclodextrin solution is 3.2-4 g: 12-15 mL: 5.5-7 mL: 28-33 mL: 70-76 mL.

7. The modified carbon black for coatings according to claim 2, characterized in that The modified β-cyclodextrin solution in step A4 is prepared by mixing modified β-cyclodextrin and N,N-dimethylformamide in a ratio of 10-15 g: 34-49 mL; The temperature during the heating reaction is 40-50°C and the reaction time is 1-1.5h: The temperature during the heating reflux is 55-62° C., and the reaction time is 4.5-5.5 h.

8. The modified carbon black for coatings according to claim 1, characterized in that The solvent is any one of xylene, acetone, methyl pyruvate, propanol, and naphtha; The resin is at least one of phenolic resin, epoxy resin and polyacrylic resin.

9. The modified carbon black for coatings according to claim 1, characterized in that The wetting agent is at least one of triethyl phosphate, dimethyl phosphate, and octanolamine; The dispersant is any one of polybutyl acrylate, polyisobutyl acrylate, polyvinyl ester and polyvinyl ester.

10. The method for preparing modified carbon black for coatings according to any one of claims 1 to 9, characterized in that: The following steps are involved: Add the modified carbon black compound, wetting agent and dispersant to the solvent, stir at a speed of 140-180 rpm for 20-25 minutes, then add carbon black particles and resin and stir for 8-11 minutes to obtain modified carbon black.

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