A highly dispersible modified carbon black and its preparation method

Abstract

This invention discloses a highly dispersible modified carbon black and its preparation method. The method first modifies the surface of carbon black through liquid-phase oxidation, introducing reactive carboxyl groups onto the carbon black surface. Then, a Steglich esterification reaction is used to graft terminal hydroxyl compounds onto the surface of the oxidized carbon black, thus preparing a highly dispersible modified carbon black. The carbon black prepared by this invention solves the problem of poor dispersion of carbon black in ethylene glycol solution, ensuring good dispersibility in ethylene glycol. The modified carbon black prepared by this method has a maximum particle size of only 142.3 nm and a PDI dispersion coefficient of only 0.032 in ethylene glycol solution. The modified carbon black prepared by this method also exhibits good heat resistance and storage stability; its stability reaches over 96% after heating at 120℃ for 2 hours and over 95% after storage for 10 days.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology, specifically relating to a highly dispersible modified carbon black and its preparation method. Background Technology

[0002] Polyester fiber is the largest category of chemical fibers, and black polyester fiber is the colored polyester fiber with the largest production and usage. It is widely used in clothing fabrics, home textiles, blackout curtains, and automotive interiors due to its high strength and modulus, good wrinkle resistance and shape retention, durability, low water absorption, good light-blocking properties, and low price. Black polyester is often obtained through pre-spinning solution dyeing and post-spinning fiber dyeing. Post-spinning fiber dyeing involves dyeing the polyester fiber filaments. Colored fibers obtained in this way have poor color fastness, and the dyeing process generates large amounts of dyeing and finishing wastewater and COD emissions, causing serious environmental pollution and high energy consumption. In the current era of "low-carbon economy and energy conservation and emission reduction," green and environmentally friendly dyeing methods have become a research hotspot. Pre-spinning solution dyeing involves adding pigments or dyes during fiber synthesis to directly obtain colored fibers. This method disperses the pigments or dyes within the fiber, resulting in high color fastness. Because it eliminates the need for post-dyeing and finishing processes for anhydrous dyeing, it saves energy consumption and reduces carbon dioxide emissions, making it an environmentally friendly dyeing method.

[0003] Carbon black is widely used as an excellent colorant and reinforcing agent. Compared with other inorganic black pigments and organic black colorants, carbon black has many advantages, such as its hiding power, color stability, solvent resistance, acid and alkali resistance, and thermal stability, which are unmatched by other black pigments. Carbon black is an important black pigment used in the solution coloring of polyester fibers. During the solution coloring process of polyester fibers, carbon black particles form strongly aggregated aggregates in ethylene glycol, and the repulsive force between these carbon black particles is very small. The surface of carbon black also has very low compatibility with ethylene glycol. Therefore, it is somewhat difficult to obtain a stable and good ethylene glycol-based carbon black suspension system.

[0004] Due to its tendency to agglomerate and disperse, carbon black can easily cause uneven dyeing and dull color when used for fiber dyeing or solution dyeing. Therefore, improving the dispersibility and dispersion stability of carbon black in a medium is essential. To improve the dispersion performance of carbon black in solution, physical or chemical modifications are performed, such as oxidation modification, grafting modification, dispersant dispersion, and grinding dispersion. Adding functional groups and functional polymers to the surface of carbon black improves its application performance. For example, patent CN110964349A discloses a method of adding heteropolyacids when oxidizing carbon black with hydrogen peroxide, which increases the hydrophilic groups on the carbon black surface and provides good dispersibility in water; patent CN108624090A discloses a method of grafting polyvinyl alcohol onto carbon black, which produces carbon black with good dispersibility in a polymer matrix; and patent CN113549347A discloses a method of grafting carbon black with an ethylene-propylene-vinyl alcohol copolymer, which improves the dispersibility of carbon black and significantly improves its blackness when applied to ink, coating, and paint systems. While these methods can improve the dispersibility of carbon black in water, the dispersibility of the modified carbon black prepared in ethylene glycol is not ideal, thus limiting the application of modified carbon black in fiber dyeing. Summary of the Invention

[0005] The purpose of this invention is to develop nano-carbon black with good dispersibility in ethylene glycol system, so as to meet the requirements of dope dyeing for carbon black such as viscose fiber, Lyocell fiber, polylactic acid fiber, polyamide fiber and polyester fiber, and solve the problem of poor dispersion of carbon black in ethylene glycol.

[0006] To achieve the above objectives, the present invention provides a highly dispersible modified carbon black, wherein the modified carbon black is obtained by oxidizing carbon black with a liquid-phase oxidant to obtain oxidized carbon black, and then linking the oxidized carbon black with a terminal hydroxyl compound through a Steglich esterification reaction, thereby grafting polymer chains onto the surface of the carbon black.

[0007] In one embodiment of the present invention, the carbon black includes one of furnace black, channel black, and pyrolysis black.

[0008] In one embodiment of the present invention, the liquid-phase oxidant includes at least one of nitric acid, hydrogen peroxide, ammonium persulfate, and potassium permanganate solution.

[0009] In one embodiment of the present invention, the hydroxyl-terminated compound includes at least one of ethylene glycol, polyethylene glycol 200, polyethylene glycol 600, polyethylene glycol 800, and polyethylene glycol 1000.

[0010] In one embodiment of the present invention, the mass ratio of the terminal hydroxyl compound to carbon black is 0.1 to 3.

[0011] The present invention also provides a method for preparing the above-mentioned modified carbon black, comprising the following steps:

[0012] (1) Carbon black was oxidized and modified by liquid phase oxidant to obtain oxidized carbon black;

[0013] (2) Add carbon black oxide and hydroxyl-terminated compounds to an organic solvent, disperse them, add DMAP and DCC to obtain a mixture, react the mixture at 20-60℃ for 12-30h, centrifuge at 8000rpm for 20min, wash, dry at 100℃ for 2h, grind the dried powder to obtain modified carbon black.

[0014] In one embodiment of the present invention, in step (1), the ratio of the liquid phase oxidant to carbon black is in the range of 5:1 to 20:1, the carbon black includes one of furnace black, channel black, and pyrolysis black, and the liquid phase oxidant includes at least one of nitric acid, hydrogen peroxide, ammonium persulfate, and potassium permanganate solution.

[0015] In one embodiment of the present invention, in step (1), the temperature during oxidation modification is 50-100°C and the time is 2-8 hours.

[0016] In one embodiment of the present invention, in step (2), the organic solvent is one of N,N-dimethylformamide, dichloromethane, and trichloromethane.

[0017] In one embodiment of the present invention, in step (2), the dispersion method includes magnetic stirring dispersion or ultrasonic dispersion, wherein the magnetic stirring speed range is 20 rpm and the stirring time is 60 min; the ultrasonic dispersion power is 40 kHz and the ultrasonic treatment is 10 to 30 min.

[0018] In one embodiment of the present invention, in step (2), after dispersion, the mass fraction of the carbon black oxide in the organic solvent is 1-40%, preferably 20-40%.

[0019] In one embodiment of the present invention, the amount of DCC added is 0.1 to 10% of the mass of carbon black oxide, preferably 5 to 10%.

[0020] In one embodiment of the present invention, the amount of DMAP added is 1 to 10% of the mass of DCC, preferably 5 to 10%.

[0021] The present invention also provides an application of the above-mentioned modified carbon black in the textile field.

[0022] In one embodiment of the present invention, the application includes dyeing the fiber with modified carbon black as a colorant or performing fiber solution dyeing.

[0023] Beneficial effects of the present invention

[0024] (1) A reactive carboxyl group is introduced onto the surface of carbon black by liquid-phase oxidation, and then reacted with a hydroxyl compound by Steglich esterification to introduce functional molecular chains onto the carbon black surface. Modified carbon black is prepared by filtration, washing, and drying. This method has the advantages of simple production process, easy operation, and high grafting rate.

[0025] (2) The modified carbon black prepared by the method of the present invention not only has good dispersibility in aqueous solution, but also has high dispersibility in ethylene glycol solution. Its maximum particle size in ethylene glycol is only 142.3 nm and its PDI dispersion coefficient is only 0.032.

[0026] (3) The modified carbon black prepared by the method of the present invention also has good heat resistance and storage stability. PEG200-OCB and PEG600-OCB have the best heat resistance, and their stability is still above 96% after heating at 120℃ for 2 hours; PEG800-OCB has the best storage (storage) stability, and its stability is still above 95% after 10 days of storage. Attached Figure Description

[0027] Figure 1 The images show the XRD patterns of the original carbon black and carbon oxide black in Example 1.

[0028] Figure 2 XPS full spectrum images of 4hOCB prepared in Example 1 and raw carbon black;

[0029] Figure 3 This is a schematic diagram of the O element peaks of the 4hOCB prepared in Example 1 and the original carbon black.

[0030] Figure 4 FESEM images of the original carbon black and the modified carbon black prepared in Examples 2-4;

[0031] Figure 5 The thermal stability curves of the carbon black 4hOCB from Examples 1-4 and the prepared modified carbon black in ethylene glycol solution are shown.

[0032] Figure 6 The stability curves of carbon black 4hOCB from Examples 1-4 and the prepared modified carbon black in ethylene glycol solution are shown.

[0033] Figure 7 The thermogravimetric curves are those of the modified carbon black prepared in Examples 1-4. Detailed Implementation

[0034] In order to better understand the technical content of the present invention, the following embodiments are provided in detail. The purpose of these embodiments is only to better understand the content of the present invention and not to limit the scope of protection of the present invention.

[0035] Test method:

[0036] Heat resistance stability: 10 mL of carbon black dispersion was placed in a beaker and sealed. The mixture was kept at 60, 70, 80, 90, 100, and 120 °C for 2 hours each. The upper layer of the pigment was then collected and diluted 1000 times with ethylene glycol. The change in carbon black particle size in the ethylene glycol pigment was measured using a Nano-ZS90 potentiometric and particle size analyzer. The high-temperature stability S was calculated using the formula. T :

[0037]

[0038] Where d0 and d T The values ​​are the particle size of the dispersion before and after heating, in nm.

[0039] Storage stability: A certain amount of carbon black or carbon black oxide was prepared into a 1% ethylene glycol-based carbon black dispersion and allowed to stand for 14 days. At regular intervals, the upper layer of the solution was taken and diluted 1000 times with ethylene glycol. The particle size change was measured using a Nano-ZS90 potentiometer and particle size analyzer, and the storage stability Sc was calculated using the formula:

[0040]

[0041] Where d0 and dc are the particle sizes of the dispersion before and after standing, respectively, in nm.

[0042] Thermogravimetric curve test: 5 mg of carbon black was placed in a crucible and their thermogravimetric curves were measured using a TGA2 fully automatic thermogravimetric analyzer. The test conditions were under N2 conditions, with a temperature range of 40 to 800 °C and a heating rate of 10 °C / min.

[0043] Example 1

[0044] 1. Effect of oxidation treatment time on the dispersibility of carbon black oxide in water.

[0045] 4g of carbon black was treated with 20g of nitric acid solution (65% concentration) at 80℃, followed by multiple centrifugation and washing until pH 5, drying, and grinding to obtain carbon black oxide. The carbon black oxides prepared at treatment times of 0h, 2h, 4h, 6h, and 8h were named primary CB, 2hOCB, 4hOCB, 6hOCB, and 8hOCB, respectively. The zeta potential and zeta potential of these carbon black oxides in aqueous solution are shown in Table 1. Table 1 shows that 4hOCB exhibits the best dispersibility in aqueous solution. The XRD images of primary carbon black and carbon black oxide are shown below. Figure 1As shown, the original carbon black exhibited diffraction peaks at 24.37° and 42.47°, while the diffraction peaks of OCB were at the same positions as those of the original carbon black, indicating that the oxidation within the experimental time frame did not cause serious damage to the main structure of the carbon black.

[0046] from Figure 2 and Figure 3 It can be seen that the O element signal on the carbon black surface increases significantly after oxidation. The proportions of C=O and COO- on the carbon black surface increase significantly after oxidation, from 18.06% and 2.94% for CB to 34.44% and 21.64% for COO-.

[0047] Table 1. Particle size and Zeta potential of raw carbon black and carbon oxide at various treatment times in aqueous solution.

[0048] sample Particle size / nm Zeta potential / mV Original CB 6686 -19.8 2hOCB 167.2 -22.3 4hOCB 156.5 -30.4 6hOCB 162.1 -34.2 8hOCB 174.9 -35.9

[0049] 2. A method for preparing highly dispersible modified carbon black, comprising the following steps:

[0050] (1) Place 4g of carbon black in 20g of nitric acid solution (concentration of 65%), treat at 80℃ for 4h, centrifuge to separate the carbon black, wash until pH is 5, dry and grind to obtain carbon black oxide 4hOCB.

[0051] (2) Weigh 1g of 4hOCB and 2g of PEG600 and add them to 40mL of N,N-dimethylformamide. Disperse the mixture by sonication for 10min. Then add 1g of DCC and 0.1g of DMAP. Transfer the reaction system to a magnetic stirrer and react for 24h. After filtration, washing, and drying, grind the dried powder to obtain modified carbon black PEG600-OCB.

[0052] from Figure 4 As can be seen, the aggregation degree of modified carbon black PEG600-OCB in ethylene glycol is significantly reduced. Tests showed that the particle size of modified carbon black PEG600-OCB in water was 172.9 nm, with a PDI of 0.137. In ethylene glycol, the dispersed particle size was 132.1 nm, with a PDI of 0.091.

[0053] Example 2

[0054] The difference between Example 2 and Example 1 is that, in the preparation of modified carbon black, 2g of PEG600 is replaced with 0.67g of PEG200 in step (2).

[0055] from Figure 4As can be seen, the aggregation degree of modified carbon black PEG200-OCB in ethylene glycol is significantly reduced. Tests showed that the particle size of modified carbon black PEG200-OCB in ethylene glycol was 133.2 nm, with a PDI of 0.096; while in water, the particle size was 194.1 nm, with a PDI of 0.164.

[0056] Example 3

[0057] The difference between Example 3 and Example 1 is that, in the preparation of modified carbon black, 2g of PEG600 was replaced with 2.68g of PEG800 in step (2).

[0058] from Figure 4 As can be seen, the aggregation degree of modified carbon black PEG800-OCB in ethylene glycol is significantly reduced. Tests showed that the particle size of modified carbon black PEG800-OCB in ethylene glycol was 141.2 nm, with a PDI of 0.071; while in water, the particle size was 172.9 nm, with a PDI of 0.137.

[0059] Example 4

[0060] The difference between Example 4 and Example 1 is that, in the preparation of modified carbon black, 2g of PEG600 was replaced with 0.21g of ethylene glycol in step (2).

[0061] Tests showed that EG-OCB has a particle size of 142.3 nm and a PDI of 0.032 in ethylene glycol, and a particle size of 204.7 nm and a PDI of 0.201 in water.

[0062] Figures 5-7 The thermal stability curves, storage stability (placement stability) curves, and thermogravimetric curves of the carbon black 4hOCB and modified carbon black prepared in Examples 1-4 are given respectively. Figure 5 As can be seen, PEG200-OCB and PEG600-OCB exhibit the best heat resistance, maintaining a stability of over 96% even after heating at 120℃ for 2 hours. Figure 6 As can be seen, the stability of grafted carbon black is better than that of carbon black 4hOCB, with PEG800-OCB showing the best stability, maintaining above 95% stability even after 10 days. Figure 7 As can be seen, the polymer has been successfully grafted onto the carbon black surface, and the grafted polymer mainly decomposes at 300–400℃.

[0063] Comparative Example 1

[0064] The dispersibility of carbon black MA100 in water and ethylene glycol solvents was tested directly.

[0065] Tests showed that the particle size of carbon black MA100 in water was 6686 nm, with a PDI of 1; and the particle size in ethylene glycol was 1261 nm, with a PDI of 1.

[0066] Comparative Example 2

[0067] The difference between Comparative Example 2 and Example 1 is that step (1) is omitted when preparing modified carbon black.

[0068] Tests showed that unoxidized polyethylene glycol-modified carbon black has a particle size of 1832 nm in water and 862.3 nm in ethylene glycol.

[0069] Comparative Example 3

[0070] The difference between Comparative Example 3 and Example 1 is that step (2) is omitted when preparing modified carbon black.

[0071] Tests showed that carbon black oxide has a particle size of 156.5 nm in water and 225 nm in ethylene glycol.

[0072] Comparative Example 4

[0073] The difference between Comparative Example 4 and Example 1 is that, in the preparation of modified carbon black, PEG600 was replaced with 2-amino-4-hydroxy-6-methylpyridine in step (2).

[0074] Tests showed that the modified carbon black had a particle size of 284.8 nm in water and 182.3 nm in ethylene glycol.

Claims

1. A highly dispersible modified carbon black characterized in that, The modified carbon black is obtained by oxidizing carbon black with a liquid phase oxidant to obtain oxidized carbon black, and then connecting the oxidized carbon black with a hydroxyl-terminated compound through a Steglich esterification reaction to graft a polymer chain on the surface of the carbon black; the Steglich esterification reaction is to add the oxidized carbon black and the hydroxyl-terminated compound into an organic solvent, disperse, and then add DMAP and DCC and react at 20-60℃ for 12-30h; the hydroxyl-terminated compound is polyethylene glycol 200 or polyethylene glycol 600, and the mass ratio of the hydroxyl-terminated compound to the oxidized carbon black is 0.67-2; the ratio of the added amount of DCC to the mass of the oxidized carbon black is 1:1, and the added amount of DMAP is 10% of the mass of DCC.

2. The modified carbon black of claim 1, wherein The carbon black includes one of furnace black, channel black, and pyrolysis black, and the liquid phase oxidant includes at least one of nitric acid, hydrogen peroxide, ammonium persulfate, and potassium permanganate solution.

3. A method for producing a highly dispersible modified carbon black according to claim 1 or 2, characterized in that, The method comprises the following steps: (1) oxidizing carbon black with a liquid phase oxidant to obtain oxidized carbon black; (2) adding the oxidized carbon black and a hydroxyl-terminated compound into an organic solvent, dispersing, adding DMAP and DCC to obtain a mixed solution, reacting the mixed solution at 20-60℃ for 12-30h, centrifuging at 8000rpm for 20min, washing, drying at 100℃ for 2h, grinding the dried powder, and obtaining modified carbon black; the ratio of the added amount of DCC to the mass of the oxidized carbon black is 1:1, and the added amount of DMAP is 10% of the mass of DCC.

4. The method of claim 3, wherein, In step (1), the ratio of the use amount of the liquid phase oxidant to the carbon black ranges from 5:1 to 20:1, the carbon black includes one of furnace black, channel black, and pyrolysis black, the liquid phase oxidant includes at least one of nitric acid, hydrogen peroxide, ammonium persulfate, and potassium permanganate solution, the temperature during the oxidation modification is 50-100℃, and the time is 2-8h.

5. The method of claim 3, wherein, In step (2), the organic solvent is one of N,N-dimethylformamide, dichloromethane, and trichloromethane, and the dispersion mode includes magnetic stirring dispersion or ultrasonic dispersion.

6. The method of claim 3, wherein, In step (2), after dispersion, the mass fraction of the oxidized carbon black in the organic solvent is 1-40%.

7. Use of the modified carbon black of claim 1 or 2 in the field of textiles.

8. Use according to claim 7, characterized in that, The use includes dyeing fibers or performing fiber stock solution coloring with the modified carbon black as a colorant.

Images