High-dispersity modified soft carbon black for coating and preparation method of high-dispersity modified soft carbon black

Abstract

The invention relates to the technical field of nano carbon black modification, in particular to high-dispersity modified soft carbon black for a coating and a preparation method of the high-dispersity modified soft carbon black, and the high-dispersity modified soft carbon black comprises the following raw materials in parts by mass: 29-35 parts of a modified carbon black composition A; 7.3 to 10.6 parts of a modified carbon black composition B; wherein hyperbranched polyester contained in the modified carbon black composition A has high water solubility, has a large number of active groups at the tail end, has relatively large steric hindrance, and can prevent agglomeration among carbon black particles; the amphiphilic beta-cyclodextrin can further improve the dispersity of the carbon black, and cooperates with the hyperbranched polyester to play a role, so that the agglomeration of particles is prevented through a steric hindrance effect, and meanwhile, the compatibility between molecules is improved; in the modified carbon black composition B, the surface of the carbon black is coated with a silicon dioxide layer through a microemulsion method, the dispersity of the carbon black is effectively improved through isolation of the silicon dioxide layer, and after the modified carbon black composition B is mixed with the modified carbon black composition A, synergistic interaction is achieved, and wide application prospects are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nano carbon black modification, and particularly relates to a high-dispersibility modified soft carbon black for paint and a preparation method thereof. BACKGROUND

[0002] Carbon black, also known as carbon black, is a product obtained by incomplete combustion or thermal decomposition of carbon-containing substances (coal, natural gas, heavy oil, fuel oil, etc.) under insufficient air, and belongs to a kind of black amorphous carbon with light mass and small density, with a surface area of 10-3000 m 2 / g. Due to the wide source of carbon black raw materials, low cost, and excellent chemical stability, heat resistance, electrical conductivity and other characteristics, carbon black is widely used in the fields of electrical conductivity, reinforcement, and paint and ink.

[0003] Soft carbon black is a kind of carbon black with low hardness and small particle size, which is usually prepared by frying method or low-temperature pyrolysis method, and has a large specific surface area and high surface activity. Because of its excellent coloring property, weather resistance and chemical stability, and abundant source and low price, it is often used as an important colorant in paint, but due to the characteristics of small particle size, large specific surface area and easy agglomeration, it is difficult to be stably dispersed in the water-based paint system. These defects limit the full play of the performance of carbon black and affect its application in water-based paint. Therefore, it is of great significance to improve the dispersibility of soft carbon black.

[0004] Therefore, according to the related technology in the above, it is urgent to develop a high-dispersibility modified soft carbon black for paint and a preparation method thereof. SUMMARY

[0005] Therefore, according to the related technology in the above, it is urgent to develop a high-dispersibility modified soft carbon black for paint and a preparation method thereof.

[0006] Based on the above purpose, the present application provides a high-dispersibility modified soft carbon black for paint and a preparation method thereof.

[0007] A high-dispersibility modified soft carbon black for paint comprises the following raw materials in mass parts: 29-35 parts of modified carbon black composition A, 7.3-10.6 parts of modified carbon black composition B; The modified carbon black composition A is prepared from hyperbranched polyester modified carbon black and beta-cyclodextrin; The hyperbranched polyester modified carbon black is prepared from pentaerythritol, 2,2-bishydroxymethyl propionic acid, p-aminobenzoic acid and carbon black; The modified carbon black composition B is prepared from oxidized carbon black and tetraethyl orthosilicate.

[0008] Preferably, the preparation method of the hyperbranched polyester modified carbon black is as follows: Step A1. Under a nitrogen atmosphere, pentaerythritol, 2,2-bishydroxymethyl propionic acid and 0.5% p-toluenesulfonic acid by mass fraction are sequentially added to a four-necked flask, heated to reflux to obtain a mixed solution A; Step A2. 2,2-bishydroxymethyl propionic acid and 0.5% p-toluenesulfonic acid by mass fraction are further added to the mixed solution A, and heating reflux is continued. After washing and drying, a hyperbranched polyester is obtained; Step A3. The hyperbranched polyester, p-toluenesulfonic acid, toluene and N,N-dimethylformamide are added to a four-necked flask to obtain a mixed solution B. Then, p-aminobenzoic acid solution is added to the mixed solution B, heated to reflux, and cooled after pouring into cold water. After washing and drying at 55-65°C for 22-24h, an aminated hyperbranched polyester is obtained; Step A4. The carbon black is placed in a four-necked flask, and concentrated nitric acid is added dropwise through a constant pressure funnel. After refluxing for 3-4h, the upper acid liquid is poured off, and washed with deionized water until neutral. After filtration and drying at 100-110°C to constant weight, an oxidized carbon black is obtained; Step A5. The oxidized carbon black, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole are added to a three-necked flask, stirred uniformly, and then the aminated hyperbranched polyester dissolved in N,N-dimethylformamide is added dropwise to the flask. After reaction at room temperature for 5-6h, filtration and washing are performed, and then the hyperbranched polyester modified carbon black is obtained by Soxhlet extraction for 48-50h with acetone as the solvent and drying.

[0009] Preferably, the amount ratio of the pentaerythritol, 2,2-bishydroxymethyl propionic acid and p-toluenesulfonic acid in step A1 is 0.015-0.03mol:0.06-0.12mol:0.050-0.12g; The temperature during heating reflux is 135-145°C, and the time is 1.5-2.5h.

[0010] Preferably, the amount ratio of the 2,2-bishydroxymethyl propionic acid and p-toluenesulfonic acid in step A2 is 0.12-0.2mol:0.08-0.14g; The temperature during heating reflux is 138-143°C, and the time is 2-2.5h.

[0011] Preferably, the amount ratio of the hyperbranched polyester, p-toluenesulfonic acid, toluene, N,N-dimethylformamide and p-aminobenzoic acid solution in step A3 is 5-8g:0.06-0.1g:22-29.5mL:30-40mL:39.2-45mL; The use amount ratio of p-aminobenzoic acid to N,N-dimethylformamide in the p-aminobenzoic acid solution is 7.8-12.6 g:25-33 mL; The temperature of the heating reflux is 135-145 ℃, and the time is 4.5-5.5 h.

[0012] Preferably, the use amount ratio of the oxidized carbon black, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1-hydroxybenzotriazole, N,N-dimethylformamide and the aminated hyperbranched polyester in step A5 is 5.2-7.5 g:0.6-0.84 g:0.49-0.62 g:40-60 mL:8.6-13.5 g.

[0013] Preferably, the preparation method of the modified carbon black composition A is as follows: The hyperbranched polyester modified carbon black and N,N-dimethylformamide are added into a flask, stirred uniformly, then the β-cyclodextrin solution is added dropwise into the flask, ultrasonic dispersion is performed for 20-30 min, then heating reaction is performed to obtain the modified carbon black composition A; The use amount ratio of the hyperbranched polyester modified carbon black, N,N-dimethylformamide and the β-cyclodextrin solution is 4.8-6.2 g:32-45 mL:48-73 mL; The use amount ratio of β-cyclodextrin to N,N-dimethylformamide in the β-cyclodextrin solution is 3.3-6 g:33-40 mL; The temperature of the heating reaction is 48-58 ℃, and the time is 12-14 h.

[0014] Preferably, the preparation method of the modified carbon black composition B is as follows: Step B1. The oxidized carbon black is added into the polyvinylpyrrolidone aqueous solution with pH of 0.6, stirred uniformly, then ultrasonic dispersion is performed for 20-30 min to obtain a mixed solution C; Step B2. The cetyltrimethylammonium bromide is added into a beaker, then the n-octanol, tetraethyl orthosilicate and cyclohexane are added, stirred uniformly to obtain a mixed solution D; Step B3. The mixed solution C is added dropwise into the mixed solution D, continues to stir for 20-30 min, then the ammonia ethanol solution with mass fraction of 2.5% is added, stirred uniformly, then heating reaction is performed at 75-82 ℃ for 50-70 min, after the reaction is completed, washing and drying are performed to obtain the modified carbon black composition B.

[0015] Preferably, the use amount ratio of the oxidized carbon black to the polyvinylpyrrolidone aqueous solution in step B1 is 0.3-0.5 g:5-8 mL; The amount ratio of the hexadecyl trimethyl ammonium bromide, n-octanol, tetraethyl orthosilicate and cyclohexane in step B2 is 5-7.3g:5-7.3g:1-1.8mL:20-28.6mL; The volume ratio of the mixed solution D, mixed solution C and ammonia ethanol solution in step B3 is 6-9:28-35:12-15.5.

[0016] A preparation method of a high-dispersibility modified soft carbon black for paint, comprising the following steps: Mixing the modified carbon black composition A with the modified carbon black composition B uniformly to obtain the high-dispersibility modified soft carbon black.

[0017] The present application has the following beneficial effects: The present application provides a high-dispersibility modified soft carbon black for paint and a preparation method thereof. The present application mixes a modified carbon black composition A with a modified carbon black composition B to obtain a soft carbon black with high dispersibility. The hyperbranched polyester contained in the modified carbon black composition A has high water solubility and a large number of active groups at the terminal, which facilitates grafting reaction of the carbon black. The hyperbranched polyester has large steric hindrance and cavity structure, which can prevent agglomeration between carbon black particles and effectively improve the dispersibility of the carbon black. The amphiphilic β-cyclodextrin can further improve the dispersibility of the carbon black and synergistically act with the hyperbranched polyester. The steric hindrance effect prevents agglomeration of particles. The rigid hydrophobic cavity structure of the β-cyclodextrin can better disperse the hyperbranched polyester in the paint matrix and improve the compatibility between molecules. In the modified carbon black composition B, a silica layer is coated on the surface of the carbon black by a microemulsion method. The silica layer effectively improves the dispersibility of the carbon black. After mixing with the modified carbon black composition A, the silica layer synergistically acts with the modified carbon black composition A, which has a wide application prospect compared with the prior art. DETAILED DESCRIPTION

[0018] To make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below with specific examples.

[0019] The sources and properties of some raw materials used in the present application are as follows: The tetraethyl orthosilicate is purchased from Guanghua Chemical Factory in Shantou; the hexadecyl trimethyl ammonium bromide is purchased from Fuchen Chemical Reagent Factory in Tianjin; the polyvinylpyrrolidone is purchased from Shanghai Baoao Biological Technology Co., Ltd.; the 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride is purchased from Shanghai McLean Reagent Co., Ltd.; the 1-hydroxybenzotriazole is purchased from Shanghai McLean Reagent Co., Ltd.; the pentaerythritol is purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.; the 2,2-bishydroxymethyl propionic acid is purchased from Shanghai McLean Reagent Co., Ltd.; and the p-aminobenzoic acid is purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0020] Embodiment 1: A method for preparing a high-dispersibility modified soft carbon black for coating, comprising the following ingredients by mass fraction: S1. Under a nitrogen atmosphere, sequentially add 0.015 mol of pentaerythritol, 0.06 mol of 2,2-bishydroxymethyl propionic acid, and 0.050 g of p-toluenesulfonic acid with a mass fraction of 0.5% into a four-necked flask, and heat to reflux at 135°C for 1.5 h to obtain a mixed solution A; S2. Add 0.12 mol of 2,2-bishydroxymethyl propionic acid and 0.08 g of p-toluenesulfonic acid with a mass fraction of 0.5% into the mixed solution A, and continue to heat to reflux at 138°C for 2 h, and then wash and dry to obtain a hyperbranched polyester; S3. Add 5 g of the hyperbranched polyester, 0.06 g of p-toluenesulfonic acid, 22 mL of toluene, and 30 mL of N,N-dimethylformamide into a four-necked flask to obtain a mixed solution B, and then add 39.2 mL of a p-aminobenzoic acid solution into the mixed solution B, wherein the amount ratio of p-aminobenzoic acid to N,N-dimethylformamide is 7.8 g:25 mL, heat to reflux at 135°C for 4.5 h, and then pour into cold water for cooling, and wash and dry at 55°C for 22 h to obtain an aminated hyperbranched polyester; S4. Place carbon black into a four-necked flask, and drop concentrated nitric acid into the flask through a constant-pressure funnel, reflux for 3 h, pour out the upper acid liquid, and wash with deionized water until neutral, filter, and dry at 100°C to a constant weight to obtain oxidized carbon black; S5. Add 5.2 g of the oxidized carbon black, 0.6 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 0.49 g of 1-hydroxybenzotriazole into a three-necked flask, stir uniformly, and then drop 8.6 g of the aminated hyperbranched polyester dissolved in 40 mL of N,N-dimethylformamide into the flask, react at room temperature for 5 h, filter and wash after the reaction is completed, and then extract in a Soxhlet extractor for 48 h with acetone as a solvent and dry to obtain a hyperbranched polyester modified carbon black; S6. Add 4.8 g of the hyperbranched polyester modified carbon black and 32 mL of N,N-dimethylformamide into a flask, stir uniformly, and then drop 48 mL of a β-cyclodextrin solution into the flask, wherein the amount ratio of β-cyclodextrin to N,N-dimethylformamide is 3.3 g:33 mL, ultrasonic disperse for 20 min, and then heat to react at 48°C for 12 h to obtain a modified carbon black composition A; S7. Add 0.3 g of oxidized carbon black into 5 mL of a polyvinyl alcohol aqueous solution with a pH of 0.6, stir uniformly, and then ultrasonic disperse for 20 min to obtain a mixed solution C; S8. Add 5 g of cetyltrimethylammonium bromide into a beaker, and then add 5 g of n-octanol, 1 mL of tetraethyl orthosilicate, and 20 mL of cyclohexane, and stir uniformly to obtain a mixed solution D; S9. Add 28 mL of mixture C to 6 mL of mixture D, continue stirring for 20 min, then add 12 mL of 2.5% ammonia-ethanol solution, stir evenly, and heat at 75 °C for 50 min. After the reaction is complete, wash and dry to obtain modified carbon black composition B. S10. Mix 29g of modified carbon black composition A and 7.3g of modified carbon black composition B evenly to obtain highly dispersible modified soft carbon black.

[0021] Example 2: A method for preparing highly dispersible modified soft carbon black for coatings, comprising the following raw materials in parts by weight: S1. Under a nitrogen atmosphere, 0.02 mol pentaerythritol, 0.08 mol 2,2-dimethylolpropionic acid and 0.07 g p-toluenesulfonic acid (0.5% by mass) were added sequentially to a four-necked flask and heated under reflux at 138 °C for 1.5 h to obtain mixture A. S2. Add 0.14 mol of 2,2-dimethylolpropionic acid and 0.1 g of 0.5% p-toluenesulfonic acid to the mixture A again, and continue to heat and reflux at 140℃ for 2 h. After washing and drying, hyperbranched polyester is obtained. S3. Add 6g of hyperbranched polyester, 0.07g of p-toluenesulfonic acid, 24mL of toluene and 34mL of N,N-dimethylformamide to a four-necked flask to obtain mixture B. Then add 41mL of p-aminobenzoic acid solution to mixture B, wherein the ratio of p-aminobenzoic acid to N,N-dimethylformamide is 9.5g:28mL. Heat under reflux at 138℃ for 5h. After the reaction is completed, pour into cold water for cooling, wash, and dry at 58℃ for 23h to obtain aminated hyperbranched polyester. S4. Place carbon black in a four-necked flask and add concentrated nitric acid dropwise through a constant pressure funnel. After refluxing for 3.5 hours, discard the upper acid layer, wash with deionized water until neutral, filter, and dry at 104℃ to constant weight to obtain carbon black oxide. S5. Add 6g of carbon black oxide, 0.6g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.55g of 1-hydroxybenzotriazole to a three-necked flask and stir until homogeneous. Then add 10.3g of aminated hyperbranched polyester dissolved in 45mL of N,N-dimethylformamide dropwise to the flask and react at room temperature for 5.5h. After the reaction is complete, filter and wash the product, then extract it in a Soxhlet extractor for 49h using acetone as solvent and dry it to obtain hyperbranched polyester modified carbon black. S6. 5.3 g of the hyperbranched polyester modified carbon black and 36 mL of N,N-dimethylformamide were added into a flask, after stirring uniformly, 55 mL of the β-cyclodextrin solution was added dropwise into the flask, wherein the dosage ratio of the β-cyclodextrin to N,N-dimethylformamide was 4 g: 35 mL, after ultrasonic dispersion for 24 min, heating reaction was carried out at 53℃ for 13 h, to obtain the modified carbon black composition A; S7. 0.35 g of the oxidized carbon black was added into 6 mL of the polyvinyl alcohol aqueous solution with pH of 0.6, after stirring uniformly, ultrasonic dispersion was carried out for 25 min, to obtain the mixed solution C; S8. 5.7 g of cetyltrimethylammonium bromide was added into a beaker, then 5.7 g of n-octanol, 1.3 mL of tetraethyl orthosilicate and 23 mL of cyclohexane were added, after stirring uniformly, the mixed solution D was obtained; S9. 30 mL of the mixed solution C was added dropwise into 7 mL of the mixed solution D, after continuing stirring for 24 min, 13.5 mL of the ammonia ethanol solution with mass fraction of 2.5% was added, after stirring uniformly, heating reaction was carried out at 78℃ for 55 min, after the reaction was completed, washing and drying were carried out, to obtain the modified carbon black composition B; S10. 31 g of the modified carbon black composition A was mixed uniformly with 8.4 g of the modified carbon black composition B, to obtain the high-dispersibility modified soft carbon black.

[0022] Example 3: A preparation method of the high-dispersibility modified soft carbon black for paint, comprising the following raw materials by mass fraction: S1. Under the nitrogen atmosphere, 0.025 mol of pentaerythritol, 0.1 mol of 2,2-bishydroxymethyl propionic acid and 0.09 g of p-toluenesulfonic acid with mass fraction of 0.5% were sequentially added into a four-necked flask, heating reflux was carried out at 142℃ for 2 h, to obtain the mixed solution A; S2. 0.18 mol of 2,2-bishydroxymethyl propionic acid and 0.08-0.14 g of p-toluenesulfonic acid with mass fraction of 0.5% were further added into the mixed solution A, heating reflux was continued at 140℃ for 2 h, after washing and drying, the hyperbranched polyester was obtained; S3. 7 g of the hyperbranched polyester, 0.085 g of p-toluenesulfonic acid, 26.5 mL of toluene and 37 mL of N,N-dimethylformamide were added into a four-necked flask, to obtain the mixed solution B, then 43 mL of the p-aminobenzoic acid solution was added into the mixed solution B, wherein the dosage ratio of the p-aminobenzoic acid to N,N-dimethylformamide was 11.3 g: 30 mL, heating reflux was carried out at 142℃ for 5 h, after the reaction was completed, cooling was carried out by pouring into cold water, after washing and drying at 62℃ for 23 h, the aminated hyperbranched polyester was obtained; S4. Put the carbon black into a four-necked flask, and drop concentrated nitric acid into it through a constant pressure funnel, after refluxing for 3.5 hours, pour off the upper acid liquid, and wash with deionized water until neutral, filter, and dry at 107℃ until constant weight to obtain the oxidized carbon black; S5. Put 6.8g of the oxidized carbon black, 0.78g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 0.58g of 1-hydroxybenzotriazole into a three-necked flask, stir until uniform, then drop 11.7g of the aminated hyperbranched polyester dissolved in 54mL of N,N-dimethylformamide into the flask, react at room temperature for 5.5 hours, after the reaction is completed, filter, wash, and then extract in a Soxhlet extractor for 49 hours using acetone as the solvent, and dry to obtain the hyperbranched polyester modified carbon black; S6. Put 5.7g of the hyperbranched polyester modified carbon black and 40mL of N,N-dimethylformamide into a flask, stir until uniform, then drop 65mL of a β-cyclodextrin solution into the flask, wherein the ratio of the amount of β-cyclodextrin to N,N-dimethylformamide is 5g:37mL, ultrasonic disperse for 27 minutes, and then heat at 55℃ for 13 hours to obtain the modified carbon black composition A; S7. Put 0.44g of the oxidized carbon black into 7mL of a polyvinyl alcohol aqueous solution with a pH of 0.6, stir until uniform, then ultrasonic disperse for 27 minutes to obtain the mixed liquid C; S8. Put 6.8g of cetyltrimethylammonium bromide into a beaker, then add 6.8g of n-octanol, 1.5mL of tetraethyl orthosilicate, and 25.5mL of cyclohexane, stir until uniform to obtain the mixed liquid D; S9. Drop 33mL of the mixed liquid C into 8mL of the mixed liquid D, continue to stir for 27 minutes, then add 14.5mL of a 2.5% ammonia ethanol solution, stir until uniform, then heat at 80℃ for 65 minutes, after the reaction is completed, wash, and dry to obtain the modified carbon black composition B; S10. Mix 33g of the modified carbon black composition A with 8.7g of the modified carbon black composition B until uniform, and the high dispersibility modified soft carbon black is obtained.

[0023] Example 4: A preparation method of a high dispersibility modified soft carbon black for paint, comprising the following ingredients by mass fraction: S1. Under a nitrogen atmosphere, sequentially put 0.03mol of pentaerythritol, 0.12mol of 2,2-bishydroxymethylpropionic acid, and 0.12g of a 0.5% mass fraction p-toluenesulfonic acid into a four-necked flask, heat at 145℃ to reflux for 2.5 hours to obtain the mixed liquid A; S2. Add 0.2mol of 2,2-bishydroxymethylpropionic acid and 0.14g of a 0.5% mass fraction p-toluenesulfonic acid into the mixed liquid A, continue to heat at 143℃ to reflux for 2.5 hours, wash, and dry to obtain the hyperbranched polyester. S3. 8 g of hyperbranched polyester, 0.1 g of p-toluenesulfonic acid, 29.5 mL of toluene and 40 mL of N,N-dimethylformamide were added into a four-necked flask to obtain a mixed solution B, and then 45 mL of a p-aminobenzoic acid solution was added into the mixed solution B, wherein the amount ratio of p-aminobenzoic acid to N,N-dimethylformamide was 12.6 g:33 mL, and the reaction was heated to reflux at 145°C for 5.5 h. After the reaction was completed, the reaction solution was cooled by pouring into cold water, washed, and dried at 65°C for 24 h to obtain an aminated hyperbranched polyester; S4. Carbon black was placed into a four-necked flask, and concentrated nitric acid was added dropwise into the flask through a constant pressure funnel. After the reaction was carried out at reflux for 4 h, the upper acid liquid was poured out, and the carbon black was washed with deionized water until neutral. After filtration and drying at 110°C to a constant weight, oxidized carbon black was obtained; S5. 7.5 g of the oxidized carbon black, 0.84 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.62 g of 1-hydroxybenzotriazole were added into a three-necked flask, stirred uniformly, and then 13.5 g of the aminated hyperbranched polyester dissolved in 60 mL of N,N-dimethylformamide was added dropwise into the flask. The reaction was carried out at room temperature for 6 h. After the reaction was completed, the reaction solution was filtered, washed, and then extracted in a Soxhlet extractor for 50 h using acetone as a solvent, and dried to obtain a hyperbranched polyester modified carbon black; S6. 6.2 g of the hyperbranched polyester modified carbon black and 45 mL of N,N-dimethylformamide were added into a flask, stirred uniformly, and then 73 mL of a β-cyclodextrin solution was added dropwise into the flask, wherein the amount ratio of β-cyclodextrin to N,N-dimethylformamide was 6 g:40 mL. After ultrasonic dispersion for 30 min, the reaction was carried out at 58°C for 14 h to obtain a modified carbon black composition A; S7. 0.5 g of the oxidized carbon black was added into 8 mL of a polyvinyl alcohol aqueous solution with a pH of 0.6, stirred uniformly, and then ultrasonic dispersed for 30 min to obtain a mixed solution C; S8. 7.3 g of cetyltrimethylammonium bromide was added into a beaker, and then 7.3 g of n-octanol, 1.8 mL of tetraethyl orthosilicate and 28.6 mL of cyclohexane were added into the beaker, stirred uniformly to obtain a mixed solution D; S9. 35 mL of the mixed solution C was added dropwise into 9 mL of the mixed solution D, and then stirred for 30 min. After 15.5 mL of an ammonia water ethanol solution with a mass fraction of 2.5% was added, stirred uniformly, and then the reaction was carried out at 82°C for 70 min. After the reaction was completed, the reaction solution was washed and dried to obtain a modified carbon black composition B; S10. 35 g of the modified carbon black composition A was mixed uniformly with 10.6 g of the modified carbon black composition B to obtain a high dispersibility modified soft carbon black.

[0024] Comparative Example 1: The comparative example is the same as example 1 except that no modified carbon black composition A is added during the preparation of the carbon black. The remaining steps and parameters are the same and will not be repeated. The final carbon black is obtained.

[0025] Comparative example 2: The comparative example is the same as example 1 except that no modified carbon black composition B is added during the preparation of the carbon black. The remaining steps and parameters are the same and will not be repeated. The final carbon black is obtained.

[0026] Comparative example 3: The comparative example is the same as example 1 except that the "modified carbon black composition A" is replaced by "hyperbranched polyester modified carbon black". The remaining steps and parameters are the same and will not be repeated. The final carbon black is obtained.

[0027] Comparative example 4: The comparative example is the same as example 1 except that "29g modified carbon black composition A and 7.3g modified carbon black composition B" is replaced by "29g modified carbon black composition A and 29g modified carbon black composition B". The remaining steps and parameters are the same and will not be repeated. The final carbon black is obtained.

[0028] Comparative example 5: The comparative example is the same as example 1 except that "29g modified carbon black composition A and 7.3g modified carbon black composition B" is replaced by "7.3g modified carbon black composition A and 29g modified carbon black composition B". The remaining steps and parameters are the same and will not be repeated. The final carbon black is obtained.

[0029] Performance test: Dispersion: 0.3g of the high dispersion modified soft carbon black prepared in examples 1-4 and comparative examples 1-5 was added to the water-based paint respectively. After standing for 14d, whether obvious precipitation appeared was observed. Table 1 Item dispersibility Example 1 no significant precipitation Example 2 no significant precipitation Example 3 no significant precipitation Example 4 no significant precipitation Comparative Example 1 a large amount of precipitation Comparative Example 2 a small amount of precipitation Comparative Example 3 a small amount of precipitation Comparative Example 4 a small amount of precipitation Comparative Example 5 a small amount of precipitation Data analysis: As can be seen from Table 1, the soft carbon black prepared by the present application has higher dispersibility, which may be due to that the hyperbranched polyester is prepared by esterification reaction from pentaerythritol and 2,2-bishydroxymethyl propionic acid under the catalysis of p-toluenesulfonic acid, then the amino group is introduced into the hyperbranched polyester molecule, and then grafted with the oxidized carbon black, to obtain the hyperbranched polyester modified carbon black with good water solubility, and then the hydrophobic cavity on the β-cyclodextrin is used to modify the aromatic ring in the hyperbranched polyester, to obtain the modified carbon black composition A with good dispersibility; wherein, the hyperbranched polyester has high water solubility, a large number of active groups at the end, is easy to graft with carbon black, and has large steric hindrance and cavity structure, which can prevent the agglomeration between carbon black particles, and effectively improve the dispersibility of carbon black; and the amphiphilic β-cyclodextrin can further improve the dispersibility of carbon black, and cooperates with the hyperbranched polyester to play a role, prevents the agglomeration of particles through steric hindrance effect, and also disperses the hyperbranched polyester in the coating matrix through the space anchoring effect of the rigid hydrophobic cavity structure, to improve the intermolecular compatibility; and in the modified carbon black composition B, the silica layer is wrapped on the surface of the carbon black through the microemulsion method, and through the isolation effect of the silica layer, the dispersibility of the carbon black is effectively improved after being mixed with the modified carbon black composition A.

[0030] It should be understood by those of ordinary skill in the art that the above discussion of any embodiment is merely exemplary and is not intended to suggest that the scope of the present application is limited to these examples; under the idea of the present application, the above embodiments or technical features in different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above, which are not provided in details for the sake of brevity.

[0031] The present application is intended to cover all such alternatives, modifications and variations as fall within the broad scope of the appended claims. Accordingly, any and all such modifications, variations, omissions, and equivalents are intended to be encompassed by the present application.

Claims

1. A highly dispersible modified soft carbon black for coatings, characterized in that, Includes the following quantities of raw materials: Modified carbon black composition A: 29-35 parts; Modified carbon black composition B: 7.3-10.6 parts; The modified carbon black composition A was prepared from hyperbranched polyester modified carbon black and β-cyclodextrin; The hyperbranched polyester-modified carbon black was prepared from pentaerythritol, 2,2-dimethylolpropionic acid, p-aminobenzoic acid and carbon black. The modified carbon black composition B is prepared from carbon black oxide and tetraethyl orthosilicate.

2. The highly dispersible modified soft carbon black for coatings according to claim 1, characterized in that, The preparation method of the hyperbranched polyester modified carbon black is as follows: Step A1. Under a nitrogen atmosphere, pentaerythritol, 2,2-dimethylolpropionic acid and 0.5% p-toluenesulfonic acid were added sequentially to a four-necked flask and heated to reflux to obtain mixture A; Step A2. Add 2,2-dimethylolpropionic acid and 0.5% p-toluenesulfonic acid to mixture A again, continue heating and reflux, wash and dry to obtain hyperbranched polyester; Step A3. Add hyperbranched polyester, p-toluenesulfonic acid, toluene and N,N-dimethylformamide to a four-necked flask to obtain mixture B. Then add p-aminobenzoic acid solution to mixture B, heat to reflux, and after the reaction is complete, pour into cold water for cooling, wash, and dry at 55-65℃ for 22-24h to obtain aminated hyperbranched polyester. Step A4. Place carbon black in a four-necked flask and add concentrated nitric acid dropwise through a constant pressure funnel. After refluxing for 3-4 hours, discard the upper acid layer and wash with deionized water until neutral. Filter and dry at 100-110℃ to constant weight to obtain carbon black oxide. Step A5. Add carbon black oxide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole to a three-necked flask and stir until homogeneous. Then, add the aminated hyperbranched polyester dissolved in N,N-dimethylformamide dropwise to the flask and react at room temperature for 5-6 hours. After the reaction is complete, filter and wash the mixture, then extract it in a Soxhlet extractor for 48-50 hours using acetone as a solvent and dry it to obtain hyperbranched polyester modified carbon black.

3. The highly dispersible modified soft carbon black for coatings according to claim 2, characterized in that, The ratio of pentaerythritol, 2,2-dimethylolpropionic acid and p-toluenesulfonic acid used in step A1 is 0.015-0.03 mol: 0.06-0.12 mol: 0.050-0.12 g; The temperature during the heating and reflux process is 135-145℃, and the time is 1.5-2.5h.

4. The highly dispersible modified soft carbon black for coatings according to claim 2, characterized in that, The ratio of 2,2-dimethylolpropionic acid to p-toluenesulfonic acid in step A2 is 0.12-0.2 mol: 0.08-0.14 g; The temperature during the heating and reflux process is 138-143℃, and the time is 2-2.5h.

5. The highly dispersible modified soft carbon black for coatings according to claim 2, characterized in that, The ratio of the hyperbranched polyester, p-toluenesulfonic acid, toluene, N,N-dimethylformamide and p-aminobenzoic acid solution used in step A3 is 5-8g:0.06-0.1g:22-29.5mL:30-40mL:39.2-45mL; The ratio of p-aminobenzoic acid to N,N-dimethylformamide in the p-aminobenzoic acid solution is 7.8-12.6 g: 25-33 mL. The temperature during the heating and reflux process is 135-145℃, and the time is 4.5-5.5h.

6. The highly dispersible modified soft carbon black for coatings according to claim 2, characterized in that, The ratio of carbon black oxide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1-hydroxybenzotriazole, N,N-dimethylformamide and aminated hyperbranched polyester in step A5 is 5.2-7.5g:0.6-0.84g:0.49-0.62g:40-60mL:8.6-13.5g.

7. The highly dispersible modified soft carbon black for coatings according to claim 1, characterized in that, The modified carbon black composition A is prepared as follows: Hyperbranched polyester modified carbon black and N,N-dimethylformamide were added to a flask and stirred until homogeneous. Then, β-cyclodextrin solution was added dropwise to the flask. After ultrasonic dispersion for 20-30 minutes, the mixture was heated to obtain modified carbon black composition A. The ratio of the hyperbranched polyester modified carbon black, N,N-dimethylformamide and β-cyclodextrin solution is 4.8-6.2 g: 32-45 mL: 48-73 mL; The ratio of β-cyclodextrin to N,N-dimethylformamide in the β-cyclodextrin solution is 3.3-6 g: 33-40 mL; The heating reaction is carried out at a temperature of 48-58℃ for 12-14 hours.

8. The highly dispersible modified soft carbon black for coatings according to claim 1, characterized in that, The modified carbon black composition B is prepared as follows: Step B1. Add carbon black oxide to a polyvinylpyrrolidone aqueous solution with a pH of 0.6, stir evenly, and then ultrasonically disperse for 20-30 minutes to obtain mixture C; Step B2. Add hexadecyltrimethylammonium bromide to a beaker, then add n-octanol, tetraethyl orthosilicate and cyclohexane, stir until homogeneous to obtain mixture D; Step B3. Add mixture C dropwise to mixture D, continue stirring for 20-30 minutes, then add a 2.5% (w / w) ammonia-ethanol solution, stir evenly, and heat at 75-82℃ for 50-70 minutes. After the reaction is complete, wash and dry to obtain modified carbon black composition B.

9. The highly dispersible modified soft carbon black for coatings according to claim 8, characterized in that, The ratio of carbon black oxide to polyvinylpyrrolidone aqueous solution in step B1 is 0.3-0.5g:5-8mL; The ratio of hexadecyltrimethylammonium bromide, n-octanol, tetraethyl orthosilicate, and cyclohexane used in step B2 is 5-7.3g:5-7.3g:1-1.8mL:20-28.6mL; The volume ratio of the mixture D, mixture C and ammonia-ethanol solution in step B3 is 6-9:28-35:12-15.

5.

10. The method for preparing highly dispersible modified soft carbon black for coatings according to any one of claims 1-9, characterized in that, Includes the following steps: The modified carbon black composition A and the modified carbon black composition B are mixed evenly to obtain highly dispersible modified soft carbon black.