Preparation of modified carbon black and application of modified carbon black in polyester fiber color master batch

Abstract

The invention discloses preparation of modified carbon black and application of the modified carbon black in a polyester fiber color master batch, and belongs to the technical field of fine chemical engineering. According to the invention, a hyperdispersant aqueous solution is added in the cooling link of carbon black production, and the hyperdispersant is adopted to carry out surface modification on carbon black, so that the carbon black can be more uniformly dispersed in the polyester fiber; the hyperdispersant is wrapped on the surface of the carbon black, and the color master batch is prepared to be applied to polyester fiber stock solution coloring, so that the agglomeration phenomenon of carbon black particles in polyester fibers can be avoided, the problems of overhigh filter pressing value, poor spinnability, non-uniform color distribution and the like during polyester spinning are solved, and the polyester fiber stock solution coloring quality is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of fine chemical engineering, and particularly relates to the preparation of modified carbon black and its application in polyester fiber masterbatch. Background Art

[0002] Carbon black is formed by natural gas or other hydrocarbon substances under the conditions of pyrolysis or incomplete combustion. Different production methods of carbon black result in different properties and elemental compositions of the prepared carbon black. Commonly used methods for preparing carbon black pigments include: tank process, furnace process, and thermal cracking process. In the existing technology, oil furnace carbon black is the most main production method of carbon black at present because of its wide source of production raw materials, high product yield, convenient automation operation, and flexible process adjustment.

[0003] During the cooling process of the product, adding an aqueous dispersant solution can improve the dispersibility of carbon black particles, make the powdered carbon black form finer particles, effectively reduce the adsorption of powdered carbon black, reduce carbon black wall sticking, and prevent carbon black from blocking the pipeline. Commonly used dispersants are mostly lignin-based dispersants, which can improve the dispersion of carbon black in aqueous solution. However, traditional lignin contains more impurities, which will reduce the quality of carbon black.

[0004] The growing carbon black market benefits from the increasing consumption in rubber tires and plastic products. In plastic products, carbon black is often applied in the form of masterbatch, especially in the coloring of chemical fiber spinning solution. Pigments, carrier resins, processing aids and other raw materials are prepared into chemical fiber masterbatch through processes such as mixing, extrusion, cooling, pelletizing, and drying. Adding carbon black in plastic coloring mostly uses black masterbatch for coloring. However, due to the poor compatibility between carbon black and the resin system, it is easy to agglomerate in the resin system, resulting in problems such as color difference and decreased processing performance. The commonly used solution is to add a coupling agent during the processing of masterbatch, or to carry out coupling agent modification treatment on carbon black to improve the compatibility of carbon black in the resin system. However, this method will correspondingly increase the production cost, and it is easy to disperse unevenly, unable to form a good dispersion effect in the polyester carrier, and easy to appear phenomena such as carbon black particle agglomeration, which will lead to phenomena such as floating filaments and broken ends in subsequent spinning, seriously affecting the quality of the spinning solution colored fibers. Summary of the Invention

[0005] [Technical Problem]

[0006] The problems to be solved by the present invention are that the quality of carbon black prepared by using lignin-based dispersants is poor, and the means to improve the compatibility of carbon black in the resin system in the existing technology still have high costs, cannot form a good dispersion effect in the resin carrier, and are easy to appear phenomena such as carbon black particle agglomeration, which will lead to phenomena such as floating filaments and broken ends in subsequent spinning, seriously affecting the quality of the spinning solution colored fibers.

[0007] [Technical Solution]

[0008] To solve the above problems, the present invention provides a preparation of modified carbon black and its application in polyester fiber masterbatch. By adding an aqueous solution of a hyperdispersant to the cooling process of carbon black production, the physical and chemical properties of the carbon black surface can be changed, the compatibility between the modified carbon black and the polyester system can be enhanced, and thus the coloring effect of carbon black in polyester can be improved, solving the problems of poor dispersion performance, poor spinnability, and too high pressure filtration value of carbon black in the coloring of polyester fiber dope.

[0009] The present invention provides a method for preparing modified carbon black, which includes the following steps;

[0010] (1) First, preheat the air and coal tar. Heat the air to 650 - 850 °C through an air heater and send it into the reaction furnace; then preheat and raise the temperature of the coal tar to 150 - 350 °C, and then send it into the reaction furnace. The introduced air and coal tar serve as reaction raw materials;

[0011] (2) Feed natural gas and the heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream with a temperature of 1500 - 1800 °C. Then feed the coal tar into the reaction furnace, and under high-temperature conditions, it rapidly cracks to generate carbon black and flue gas;

[0012] (3) Feed cooling water into the reaction furnace to rapidly reduce its temperature and terminate the reaction;

[0013] (4) When the temperature of the reaction furnace drops to 200 - 300 °C, feed the aqueous solution of the hyperdispersant into the reaction furnace to rapidly reduce the temperature and make the hyperdispersant wrap on the surface of the carbon black;

[0014] (5) The cooled carbon black and flue gas are separated and collected through a bag filter to obtain carbon black.

[0015] In an embodiment of the present invention, in step (4), the type of the hyperdispersant is one or more of styrene - maleic anhydride copolymer, polyvinylpyrrolidone, and modified polyacrylic acid.

[0016] In an embodiment of the present invention, in step (4), in order to improve the dispersion effect of the styrene - maleic anhydride copolymer hyperdispersant in water, sodium hydroxide or potassium hydroxide is added to the aqueous solution of the hyperdispersant to react with some carboxyl groups on the maleic anhydride, making the pH value of the solution 8 - 10.

[0017] In an embodiment of the present invention, in step (4), the structural formula of the styrene - maleic anhydride copolymer hyperdispersant is:

[0018]

[0019] Among them, m:n is 1:0.03 to 1:0.15, 10 ≤ m ≤ 200, 0 ≤ n ≤ 40, and both m and n are integers; R1 is one of OH, alkyl hydroxyl, and polyester hydroxyl groups; R2 is one of OH, alkyl hydroxyl, and polyester hydroxyl groups.

[0020] In an embodiment of the present invention, in step (4), when the alkyl hydroxyl is of the isobutanol type, the structure is as shown in formula (Ⅰ):

[0021]

[0022] When the polyester hydroxyl is of the monohydroxy polycaprolactone type, the structure is as shown in formula (Ⅱ):

[0023]

[0024] In the said formula (Ⅱ), R3 is H or an alkyl group with less than 5 carbon atoms, and x is an integer less than 10.

[0025] In an embodiment of the present invention, in step (4), the Mn of the styrene - maleic anhydride copolymer type hyperdispersant is 10,000 to 40,000.

[0026] In an embodiment of the present invention, in step (4), the structural formula of the polyvinylpyrrolidone type hyperdispersant is:

[0027]

[0028] Furthermore, w is an integer from 40 to 3,500, and the Mn of the polyvinylpyrrolidone type hyperdispersant is 8,000 to 360,000.

[0029] In an embodiment of the present invention, in step (4), the structural formula of the modified polyacrylic acid type hyperdispersant is:

[0030]

[0031] Furthermore, z is an integer from 10 to 60, where R4 is one or several of sodium salt, ammonium salt, and potassium salt; the Mn of the modified polyacrylic acid type hyperdispersant is 1,000 to 5,000.

[0032] In an embodiment of the present invention, in step (4), the mass fraction of the hyperdispersant aqueous solution is 5% to 25%.

[0033] In an embodiment of the present invention, in step (4), the mass ratio of coal tar to the hyperdispersant aqueous solution is 1:0.1 to 1.

[0034] In an embodiment of the present invention, in step (4), the reaction furnace temperature is reduced to 200 - 270 °C, and the hyperdispersant aqueous solution is introduced.

[0035] The present invention provides carbon black prepared by the above-mentioned method.

[0036] The present invention provides the application of the above-mentioned carbon black in polyester fiber masterbatch.

[0037] The present invention provides the application of the above-mentioned carbon black in as-spun colored polyester fiber.

[0038] The present invention provides a method for preparing as-spun colored polyester fiber, comprising the following steps:

[0039] (1) Granulate the above-mentioned carbon black by dry granulation to obtain carbon black granules, place the carbon black granules in a vacuum oven at 100 °C for drying treatment for 4 - 6 h, and place the bottle-grade PET resin powder in a vacuum oven at 130 °C for drying treatment for 4 - 6 h;

[0040] (2) Then, uniformly blend the dried bottle-grade PET resin powder and carbon black granules in a certain proportion, and successively carry out processes such as melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch;

[0041] (3) Place the PET black masterbatch in a vacuum oven at 130 - 150 °C for drying for 8 - 12 h until the moisture content drops below 50 ppm, mix it uniformly with fiber-grade PET spinning chips in a mass ratio of 1:100 - 5:100, and melt-spin to obtain as-spun colored polyester fiber.

[0042] In an embodiment of the present invention, in step (1), the moisture content of the carbon black granules and the bottle-grade PET resin powder is controlled below 500 ppm.

[0043] In an embodiment of the present invention, in step (2), the mass ratio of the carbon black granules to the bottle-grade PET resin powder is 25 - 35:65 - 75.

[0044] [Beneficial effects]

[0045] The present invention uses a hyperdispersant to modify the surface of carbon black; adding a dispersant during the carbon black production stage helps the carbon black to disperse more uniformly in polyester fiber; wrapping the hyperdispersant on the surface of carbon black and preparing masterbatch for application in as-spun colored polyester fiber can avoid the agglomeration phenomenon of carbon black particles in polyester fiber, solve problems such as too high filter pressure value, poor spinnability, and uneven color distribution during polyester spinning, and improve the quality of as-spun colored polyester fiber. Description of the drawings

[0046] Figure 1SEM images of polyester fibers, where (a) is the polyester fiber without added carbon black; (b) is the black polyester fiber prepared in Example 2; (c) is the black polyester fiber prepared in Example 7; (d) is the black polyester fiber prepared in Example 11; (e) is the black polyester fiber prepared in Comparative Example 2; (f) is the black polyester fiber prepared by adding carbon black without a dispersant using the same process in Comparative Example 3; (g) is the black polyester fiber prepared using domestic carbon black in Comparative Example 4; (h) is the black polyester fiber prepared using imported carbon black in Comparative Example 5.

[0047] Figure 2 The production process of furnace black carbon black. Detailed implementation manners

[0048] The sources of the reagents used in the present invention:

[0049] Styrene-maleic anhydride copolymer superdispersants are purchased from Suzhou Shiming Science & Technology Co., Ltd., SMA series of styrene-maleic anhydride copolymer dispersants; polyvinylpyrrolidone dispersants are purchased from Sinopharm Reagents, and polyacrylate dispersants are purchased from BASF. series.

[0050] Domestic carbon black is purchased from Xinjiang Junxin Chemical Co., Ltd., with the model HPC 005WB, and imported carbon black is purchased from Cabot Corporation, Germany, with the model BP5560.

[0051] The carrier resin used in the following examples and comparative examples is polyethylene terephthalate (PET) resin, which is a common commercial resin widely used in the masterbatch industry.

[0052] The performance test methods of the present invention:

[0053] Thermal stability test of carbon black: The thermal decomposition properties of the samples are analyzed using a thermogravimetric analyzer (TG). Under a nitrogen atmosphere, the heating rate is 20 °C / min, and the temperature rises from 25 °C to 800 °C.

[0054] Filtration performance test: Add 500 g of PET chips to rinse the equipment to make the melt pressure curve run smoothly, and record the initial pressure P0; then add 1500 g of a mixture of masterbatch and PET chips, where the mass ratio of the masterbatch to PET chips is 1:5. After the material is exhausted, add 500 g of PET chips. After 120 s, record the maximum pressure Pmax. The pigment content in the masterbatch is m (g), and the filter press value FPV = (P max - P0) / m. The experiment uses a 10 μm filter mesh. The spinnability of the masterbatch is characterized by the filtration performance test.

[0055] Observation of fiber surface morphology: The prepared polyester fibers were respectively placed on aluminum foil, sputter-coated with gold under the condition of an accelerating voltage of 30 kV, and the cross-sectional morphology of the samples was observed using a scanning electron microscope (SU1510, USA). Compared with the polyester fiber filaments without carbon black under the same process, √ indicates that it is basically similar to the cross-sectional morphology of the polyester fiber filaments, Δ indicates that there are a few particles, and ╳ indicates that there are obvious particles.

[0056] According to the national standard GB / T 14344-2008 "Test Method for Tensile Properties of Chemical Fiber Filaments", the breaking strength of the polyester fiber filaments and the dope-colored polyester fibers was tested under the following conditions: clamping length 20 mm, tensile rate 20 mm / min.

[0057] Example 1

[0058] (1) First, preheat the air and coal tar. The air was heated to 800 °C by an air heater and then sent into the reaction furnace; then the coal tar was preheated to 300 °C and subsequently sent into the reaction furnace. The introduced air and coal tar served as reaction raw materials.

[0059] (2) Natural gas and the heated air were introduced into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then the coal tar was introduced into the reaction furnace, and under high-temperature conditions, it was rapidly cracked to produce carbon black and flue gas. Note: The ratio of the introduced air to coal tar was 0.5:1.

[0060] (3) Cooling water was introduced into the reaction furnace to rapidly reduce its temperature and terminate the reaction.

[0061] (4) When the temperature of the reaction furnace dropped to 250 °C, an aqueous solution of a styrene-maleic anhydride dispersant of monohydroxy polycaprolactone type (pH 8 - 10) was introduced into the reaction furnace at a mass ratio of 0.33:1 to the coal tar, causing the temperature to rapidly decrease and the superdispersant to coat the surface of the carbon black. The cooled carbon black and flue gas were separated and collected by a bag filter and granulated by dry granulation to obtain carbon black pellets. Among them, the styrene-maleic anhydride dispersant of monohydroxy polycaprolactone type had a Mn ≈ 10000, m:n = 1:0.07, and the concentration of the dispersant aqueous solution was 15 wt%. The structure of the dispersant is as follows:

[0062]

[0063] (5) The prepared carbon black pellets were dried in a vacuum oven at 100 °C for 6 h, and the bottle-grade PET resin powder was dried in a vacuum oven at 130 °C for 6 h; the moisture content reached below 500 ppm.

[0064] (6) Then, the dried PET powder and carbon black particles are blended evenly at a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled pelletizing to obtain PET black masterbatch;

[0065] (7) The masterbatch is placed in a vacuum oven at 150 °C and dried for 10 h. When the water content drops below 50 ppm, it is mixed evenly with fiber-grade PET spinning chips at a mass ratio of 1:40, and melt-spun to obtain solution-dyed polyester fiber.

[0066] Example 2

[0067] (1) First, preheat the air and coal tar. The air is heated to 800 °C by an air heater and sent into the reaction furnace; then the coal tar is preheated to 300 °C and subsequently sent into the reaction furnace. The introduced air and coal tar serve as reaction raw materials;

[0068] (2) Natural gas and the heated air are introduced into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then the coal tar is introduced into the reaction furnace. Under high-temperature conditions, it is rapidly cracked to generate carbon black and flue gas. Note: The ratio of the introduced air to coal tar is 0.5:1;

[0069] (3) Cooling water is introduced into the reaction furnace to rapidly reduce its temperature and terminate the reaction;

[0070] (4) When the temperature of the reaction furnace drops to 250 °C, an aqueous solution of a styrene-maleic anhydride dispersant of monohydroxy polycaprolactone type (pH 8 - 10) is introduced into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, so that the temperature rapidly decreases and the superdispersant wraps around the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulated by dry granulation to obtain carbon black particles; among them, the Mn of the styrene-maleic anhydride dispersant of monohydroxy polycaprolactone type is approximately 25000, m:n = 1:0.07, and the concentration of the dispersant aqueous solution is 15 wt%; the structure of the dispersant is as follows:

[0071]

[0072] (5) The prepared carbon black is dried in a vacuum oven at 100 °C for 6 h, and the bottle-grade PET resin powder is dried in a vacuum oven at 130 °C for 6 h; the moisture content reaches below 500 ppm;

[0073] (6) Then, the dried PET powder and carbon black are blended evenly at a ratio of 70:30 by mass, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled pelletizing to obtain PET black masterbatch;

[0074] (7) Put the masterbatch into a vacuum oven at 150 °C and dry it for 10 h. After the moisture content drops below 50 ppm, mix it evenly with fiber-grade PET spinning chips according to a mass ratio of 1:40, and melt-spin to obtain solution-dyed polyester fiber.

[0075] Example 3

[0076] (1) First, preheat the air and coal tar. Heat the air to 800 °C through an air heater and send it into the reaction furnace; then preheat the coal tar to 300 °C and then send it into the reaction furnace. The introduced air and coal tar serve as reaction raw materials.

[0077] (2) Pass natural gas and the heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then pass the coal tar into the reaction furnace. Under high-temperature conditions, it quickly cracks to form carbon black and flue gas. Note: The ratio of the introduced air to coal tar is 0.5:1.

[0078] (3) Pass cooling water into the reaction furnace to quickly reduce its temperature and terminate the reaction.

[0079] (4) When the temperature of the reaction furnace drops to 250 °C, pass the aqueous solution of styrene-maleic anhydride dispersant of monohydroxy polycaprolactone type (pH 8 - 10) into the reaction furnace according to a ratio of 0.33:1 to the mass of coal tar, so that the temperature quickly drops and the superdispersant wraps around the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulated by dry granulation to obtain carbon black particles. Among them, the styrene-maleic anhydride dispersant of monohydroxy polycaprolactone type has Mn≈40000, m:n = 1:0.07, and the concentration of the dispersant aqueous solution is 15 wt%; the structure of the dispersant is as follows:

[0080]

[0081] (5) Put the prepared carbon black into a vacuum oven at 100 °C for drying treatment for 6 h, and put the bottle-grade PET resin powder into a vacuum oven at 130 °C for drying treatment for 6 h; the moisture content reaches below 500 ppm.

[0082] (6) Then, evenly blend the dried PET powder and carbon black according to a mass ratio of 70:30, and successively pass through processes such as melt extrusion by a twin-screw extruder and water-cooling granulation to obtain PET masterbatch.

[0083] (7) Put the masterbatch into a vacuum oven at 150 °C and dry it for 10 h. After the moisture content drops below 50 ppm, mix it evenly with fiber-grade PET spinning chips according to a mass ratio of 1:40, and melt-spin to obtain solution-dyed polyester fiber.

[0084] Example 4

[0085] (1) First, preheat the air and coal tar. Heat the air to 800 °C through an air heater and send it into the reaction furnace. Then, preheat the coal tar to 300 °C and subsequently send it into the reaction furnace. The introduced air and coal tar serve as reaction raw materials.

[0086] (2) Introduce natural gas and the heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream with a temperature of 1700 °C. Then, introduce the coal tar into the reaction furnace. Under high-temperature conditions, it rapidly cracks to form carbon black and flue gas. Note: The ratio of the introduced air to coal tar is 0.5:1.

[0087] (3) Introduce cooling water into the reaction furnace to rapidly reduce its temperature and terminate the reaction.

[0088] (4) When the temperature of the reaction furnace drops to 250 °C, introduce an aqueous solution of a styrene-maleic anhydride dispersant of the monohydroxy polycaprolactone type (pH 8 - 10) into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, which rapidly reduces the temperature and causes the superdispersant to coat the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulation is carried out by dry granulation to obtain carbon black granules. Among them, the styrene-maleic anhydride dispersant of the monohydroxy polycaprolactone type has Mn≈25000, m:n = 1:0.03, the concentration of the dispersant aqueous solution is 15 wt%, and the structure of the dispersant is as follows:

[0089]

[0090] (5) Place the prepared carbon black in a vacuum oven at 100 °C for drying for 6 h, and place the bottle-grade PET resin powder in a vacuum oven at 130 °C for drying for 6 h.

[0091] (6) Then, blend the dried PET powder and carbon black evenly at a mass ratio of 70:30, and successively carry out processes such as melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch.

[0092] (7) Place the masterbatch in a vacuum oven at 150 °C for drying for 10 h until the moisture content drops below 50 ppm, and mix it evenly with fiber-grade PET spinning chips at a mass ratio of 1:40, and carry out melt spinning to obtain solution-dyed polyester fiber.

[0093] Example 5

[0094] (1) First, preheat the air and coal tar. Heat the air to 800 °C through an air heater and send it into the reaction furnace. Then, preheat the coal tar to 300 °C and subsequently send it into the reaction furnace. The introduced air and coal tar serve as reaction raw materials.

[0095] (2) Feed natural gas and heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then feed coal tar into the reaction furnace, where it rapidly cracks into carbon black and flue gas under high-temperature conditions. Note: The ratio of the air fed in to the coal tar is 0.5:1;

[0096] (3) Feed cooling water into the reaction furnace to rapidly reduce its temperature and terminate the reaction;

[0097] (4) When the temperature of the reaction furnace drops to 250 °C, feed an aqueous solution of a styrene-maleic anhydride dispersant of the monohydroxy polycaprolactone type (pH 8 - 10) into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, causing the temperature to rapidly decrease and the superdispersant to coat the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter. Granulation is carried out by dry granulation to obtain carbon black granules. Among them, the styrene-maleic anhydride dispersant of the monohydroxy polycaprolactone type has a Mn ≈ 25000, m:n = 1:0.12, and the concentration of the dispersant aqueous solution is 15 wt%; the structure of the dispersant is as follows:

[0098]

[0099] (5) Place the prepared carbon black in a vacuum oven at 100 °C for drying for 6 h, and place the bottle-grade PET resin powder in a vacuum oven at 130 °C for drying for 6 h; the moisture content reaches below 500 ppm;

[0100] (6) Then blend the dried PET powder and carbon black evenly at a mass ratio of 70:30, and successively pass through processes such as melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch;

[0101] (7) Place the masterbatch in a vacuum oven at 150 °C for drying for 10 h until the moisture content drops below 50 ppm, and mix it evenly with fiber-grade PET spinning chips at a mass ratio of 1:40, and carry out melt spinning to obtain the as-spun colored polyester fiber.

[0102] Example 6

[0103] (1) First, preheat the air and preheat the coal tar. Heat the air to 800 °C by an air heater and feed it into the reaction furnace; then preheat and raise the temperature of the coal tar to 300 °C, and then feed it into the reaction furnace. The air and coal tar fed in are used as reaction raw materials;

[0104] (2) Feed natural gas and heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then feed coal tar into the reaction furnace, where it rapidly cracks into carbon black and flue gas under high-temperature conditions. Note: The ratio of the air fed in to the coal tar is 0.5:1;

[0105] (3) Coolant water is introduced into the reaction furnace to rapidly reduce its temperature and terminate the reaction.

[0106] (4) When the temperature of the reaction furnace drops to 250 °C, an aqueous solution of styrene - maleic anhydride dispersant with monohydroxy polycaprolactone type (pH 8 - 10) is introduced into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, causing the temperature to rapidly decrease and enabling the hyperdispersant to coat the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulation is carried out by dry granulation to obtain carbon black pellets. Among them, the styrene - maleic anhydride dispersant of monohydroxy polycaprolactone type has Mn≈25000, m:n = 1:0.07, and the concentration of the dispersant aqueous solution is 5 wt%; the structure of the dispersant is as follows:

[0107]

[0108] (5) The prepared carbon black is dried in a vacuum oven at 100 °C for 6 h, and the bottle - grade PET resin powder is dried in a vacuum oven at 130 °C for 6 h; the moisture content reaches below 500 ppm.

[0109] (6) Then the dried PET powder and carbon black are blended evenly at a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin - screw extruder and water - cooled granulation to obtain PET black masterbatch.

[0110] (7) The masterbatch is placed in a vacuum oven at 150 °C and dried for 10 h. After the moisture content drops below 50 ppm, it is mixed evenly with fiber - grade PET spinning chips at a mass ratio of 1:40, and melt - spun to obtain solution - dyed polyester fiber.

[0111] Example 7

[0112] (1) First, air preheating and coal tar preheating are carried out. The air is heated to 800 °C by an air heater and sent into the reaction furnace; then the coal tar is preheated to 300 °C and subsequently sent into the reaction furnace. The introduced air and coal tar serve as reaction raw materials.

[0113] (2) Natural gas and the heated air are introduced into the reaction furnace for combustion to generate a high - temperature combustion gas stream at 1700 °C. Then the coal tar is introduced into the reaction furnace, and under high - temperature conditions, it rapidly cracks to form carbon black and flue gas. Note: The ratio of the introduced air to coal tar is 0.5:1.

[0114] (3) Coolant water is introduced into the reaction furnace to rapidly reduce its temperature and terminate the reaction.

[0115] (4) When the temperature of the reaction furnace drops to 250 °C, an aqueous solution of styrene-maleic anhydride dispersant mixed with monohydroxy polycaprolactone type (pH 8-10) is introduced into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, causing the temperature to drop rapidly and enabling the hyperdispersant to coat the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulation is carried out by dry granulation to obtain carbon black pellets. Among them, the styrene-maleic anhydride dispersant of monohydroxy polycaprolactone type has Mn≈25000, m:n = 1:0.07, and the concentration of the dispersant aqueous solution is 25 wt%; the structure of the dispersant is as follows:

[0116]

[0117] (5) The prepared carbon black is dried in a vacuum oven at 100 °C for 6 h, and the bottle-grade PET resin powder is dried in a vacuum oven at 130 °C for 6 h; the moisture content reaches below 500 ppm;

[0118] (6) Then the dried PET powder and carbon black are blended evenly at a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch;

[0119] (7) The masterbatch is placed in a vacuum oven at 150 °C and dried for 10 h. After the moisture content drops below 50 ppm, it is mixed evenly with fiber-grade PET spinning chips at a mass ratio of 1:40, and melt-spun to obtain solution-dyed polyester fiber.

[0120] Example 8

[0121] (1) First, preheat the air and coal tar. The air is heated to 800 °C by an air heater and sent into the reaction furnace; then the coal tar is preheated to 300 °C and subsequently sent into the reaction furnace. The introduced air and coal tar serve as reaction raw materials;

[0122] (2) Introduce natural gas and the heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then introduce the coal tar into the reaction furnace. Under high-temperature conditions, it is rapidly cracked to form carbon black and flue gas. Note: The ratio of the introduced air to coal tar is 0.5:1;

[0123] (3) Introduce cooling water into the reaction furnace to rapidly reduce its temperature and terminate the reaction;

[0124] (4) When the temperature of the reaction furnace drops to 250 °C, the aqueous solution of styrene-maleic anhydride dispersant mixed with isobutanol esterified (pH 8-10) is introduced into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, so that the temperature drops rapidly, and the hyperdispersant is wrapped on the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulation is carried out by dry granulation to obtain carbon black pellets. Among them, the Mn of the isobutanol-esterified styrene-maleic anhydride dispersant is approximately 25000, m:n = 1:0.09, and the concentration of the dispersant aqueous solution is 15 wt%; the structure of the dispersant is as follows:

[0125]

[0126] (5) The prepared carbon black is dried in a vacuum oven at 100 °C for 6 h, and the bottle-grade PET resin powder is dried in a vacuum oven at 130 °C for 6 h; the moisture content reaches below 500 ppm;

[0127] (6) Then the dried PET powder and carbon black are blended evenly at a ratio of 70:30 by mass, and are successively processed through processes such as melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch;

[0128] (7) The masterbatch is placed in a vacuum oven at 150 °C and dried for 10 h. The moisture content drops to below 50 ppm and is uniform with the fiber-grade PET spinning chips at a ratio of 1:40 by mass, and melt spinning is carried out to obtain the dope-colored polyester fiber.

[0129] Example 9

[0130] (1) First, air preheating and coal tar preheating are carried out. The air is heated to 800 °C by an air heater and sent into the reaction furnace; then the coal tar is preheated to 300 °C and then sent into the reaction furnace. The introduced air and coal tar are used as reaction raw materials;

[0131] (2) Natural gas and the heated air are introduced into the reaction furnace for combustion to generate a high-temperature combustion gas stream with a temperature of 1700 °C. Then the coal tar is introduced into the reaction furnace. Under high-temperature conditions, it is rapidly cracked to generate carbon black and flue gas. Note: The ratio of the introduced air to the coal tar is 0.5:1;

[0132] (3) Cooling water is introduced into the reaction furnace to rapidly reduce its temperature and terminate the reaction;

[0133] (4) When the temperature of the reaction furnace drops to 250 °C, the aqueous solution of styrene-maleic anhydride dispersant mixed with isobutanol esterified (pH 8-10) is introduced into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, causing the temperature to drop rapidly and enabling the hyperdispersant to coat the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulation is carried out by dry granulation to obtain carbon black pellets. Among them, the Mn of the isobutanol-esterified styrene-maleic anhydride dispersant is approximately 10,000, m:n = 1:0.09, and the concentration of the dispersant aqueous solution is 15 wt%; the structure of the dispersant is as follows:

[0134]

[0135] (5) The prepared carbon black is dried in a vacuum oven at 100 °C for 6 h, and the bottle-grade PET resin powder is dried in a vacuum oven at 130 °C for 6 h; the moisture content reaches below 500 ppm;

[0136] (6) Then the dried PET powder and carbon black are blended evenly at a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch;

[0137] (7) The masterbatch is placed in a vacuum oven at 150 °C and dried for 10 h. After the moisture content drops below 50 ppm, it is mixed evenly with fiber-grade PET spinning chips at a mass ratio of 1:40, and melt spinning is carried out to obtain solution-dyed polyester fiber.

[0138] Example 10

[0139] (1) First, air preheating and coal tar preheating are carried out. The air is heated to 800 °C by an air heater and sent into the reaction furnace; then the coal tar is preheated to 300 °C and subsequently sent into the reaction furnace. The introduced air and coal tar serve as reaction raw materials;

[0140] (2) Natural gas and the heated air are introduced into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then the coal tar is introduced into the reaction furnace. Under high-temperature conditions, it is rapidly cracked to generate carbon black and flue gas. Note: The ratio of the introduced air to coal tar is 0.5:1;

[0141] (3) Cooling water is introduced into the reaction furnace to rapidly reduce its temperature and terminate the reaction;

[0142] (4) When the temperature of the reaction furnace drops to 250 °C, the aqueous solution of styrene-maleic anhydride dispersant mixed with isobutanol esterified styrene-maleic anhydride (pH 8-10) is introduced into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, causing the temperature to drop rapidly and enabling the hyperdispersant to coat the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulation is carried out by dry granulation to obtain carbon black granules. Among them, the isobutanol esterified styrene-maleic anhydride dispersant has a Mn ≈ 40,000, m:n = 1:0.09, and the concentration of the dispersant aqueous solution is 15 wt%; the structure of the dispersant is as follows:

[0143]

[0144] (5) The prepared carbon black is dried in a vacuum oven at 100 °C for 6 h, and the bottle-grade PET resin powder is dried in a vacuum oven at 130 °C for 6 h; the moisture content reaches below 500 ppm;

[0145] (6) Then the dried PET powder and carbon black are blended evenly at a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch;

[0146] (7) The masterbatch is placed in a vacuum oven at 150 °C and dried for 10 h until the moisture content drops below 50 ppm, and then mixed evenly with fiber-grade PET spinning chips at a mass ratio of 1:40 and melt-spun to obtain solution-dyed polyester fiber.

[0147] Example 11

[0148] (1) First, preheat the air and coal tar. The air is heated to 800 °C by an air heater and sent into the reaction furnace; then the coal tar is preheated to 300 °C and subsequently sent into the reaction furnace. The introduced air and coal tar serve as reaction raw materials;

[0149] (2) Introduce natural gas and the heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then introduce the coal tar into the reaction furnace. Under high-temperature conditions, it is rapidly cracked to generate carbon black and flue gas. Note: The ratio of the introduced air to coal tar is 0.5:1;

[0150] (3) Introduce cooling water into the reaction furnace to rapidly reduce its temperature and terminate the reaction;

[0151] (4) When the temperature of the reaction furnace drops to 250 °C, an aqueous solution mixed with polyvinylpyrrolidone is introduced into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, causing the temperature to drop rapidly and enabling the hyperdispersant to coat the surface of the carbon black. The carbon black and flue gas after cooling are separated and collected by a bag filter and granulated by dry granulation to obtain carbon black pellets. Among them, the Mn of polyvinylpyrrolidone is approximately 8000, and the concentration of the dispersant aqueous solution is 15 wt%; the structure of the dispersant is as follows:

[0152]

[0153] (5) The prepared carbon black is dried in a vacuum oven at 100 °C for 6 h, and the bottle-grade PET resin powder is dried in a vacuum oven at 130 °C for 6 h; the moisture content reaches below 500 ppm.

[0154] (6) Then, the dried PET powder and carbon black are blended evenly at a ratio of 70:30 by mass and successively processed through processes such as melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch.

[0155] (7) The masterbatch is placed in a vacuum oven at 150 °C and dried for 10 h. After the moisture content drops to below 50 ppm, it is mixed evenly with fiber-grade PET spinning chips at a ratio of 1:40 by mass, and melt-spun to obtain solution-dyed polyester fibers.

[0156] Example 12

[0157] (1) First, air preheating and coal tar preheating are carried out. The air is heated to 800 °C by an air heater and sent into the reaction furnace; then the coal tar is preheated to 300 °C and subsequently sent into the reaction furnace. The introduced air and coal tar serve as reaction raw materials.

[0158] (2) Natural gas and the heated air are introduced into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then the coal tar is introduced into the reaction furnace, and under high-temperature conditions, it is rapidly cracked to generate carbon black and flue gas. Note: The ratio of the introduced air to the coal tar is 0.5:1.

[0159] (3) Cooling water is introduced into the reaction furnace to rapidly reduce its temperature and terminate the reaction.

[0160] (4) When the temperature of the reaction furnace drops to 250 °C, an aqueous solution mixed with polyvinylpyrrolidone is introduced into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, causing the temperature to drop rapidly and enabling the hyperdispersant to coat the surface of the carbon black. The carbon black and flue gas after cooling are separated and collected by a bag filter and granulated by dry granulation to obtain carbon black pellets. Among them, the Mn of polyvinylpyrrolidone is approximately 45000, and the concentration is 15 wt%; the structure of the dispersant is as follows:

[0161]

[0162] (5) Place the prepared carbon black in a vacuum oven at 100 °C for 6 h of drying treatment, and place the bottle-grade PET resin powder in a vacuum oven at 130 °C for 6 h of drying treatment; the moisture content reaches below 500 ppm;

[0163] (6) Then blend the dried PET powder and carbon black evenly at a mass ratio of 70:30, and successively pass through processes such as melt extrusion by a twin-screw extruder and water-cooling pelletizing to obtain PET black masterbatch;

[0164] (7) Place the masterbatch in a vacuum oven at 150 °C and dry for 10 h. When the moisture content drops below 50 ppm, mix it evenly with fiber-grade PET spinning chips at a mass ratio of 1:40 and conduct melt spinning to obtain solution-dyed polyester fiber.

[0165] Example 13

[0166] (1) First, preheat the air and coal tar. Heat the air to 800 °C through an air heater and send it into the reaction furnace; then preheat and raise the temperature of the coal tar to 300 °C, and then send it into the reaction furnace. The introduced air and coal tar serve as reaction raw materials;

[0167] (2) Feed natural gas and the heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream with a temperature of 1700 °C. Then feed the coal tar into the reaction furnace. Under high-temperature conditions, it quickly cracks to generate carbon black and flue gas. Note: The ratio of the introduced air to coal tar is 0.5:1;

[0168] (3) Feed cooling water into the reaction furnace to quickly reduce its temperature and terminate the reaction;

[0169] (4) When the temperature of the reaction furnace drops to 250 °C, feed an aqueous solution mixed with polyvinylpyrrolidone into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, so that the temperature quickly drops and the hyperdispersant wraps around the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulation is carried out by a dry granulation method to obtain carbon black particles. Among them, the Mn of polyvinylpyrrolidone is approximately 360000 and the concentration is 15 wt%; the structure of the dispersant is as shown below:

[0170]

[0171] (5) Place the prepared carbon black in a vacuum oven at 100 °C for 6 h of drying treatment, and place the bottle-grade PET resin powder in a vacuum oven at 130 °C for 6 h of drying treatment; the moisture content reaches below 500 ppm;

[0172] (6) Then, the dried PET powder and carbon black are blended evenly in a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled pelletizing to obtain PET masterbatch.

[0173] (7) The masterbatch is placed in a vacuum oven at 150 °C and dried for 10 h. After the moisture content drops below 50 ppm, it is mixed evenly with fiber-grade PET spinning chips in a mass ratio of 1:40, and melt-spun to obtain solution-dyed polyester fiber.

[0174] Example 14

[0175] (1) First, preheat the air and coal tar. The air is heated to 800 °C by an air heater and sent into the reaction furnace; then the coal tar is preheated to 300 °C and subsequently sent into the reaction furnace. The introduced air and coal tar serve as reaction raw materials.

[0176] (2) Introduce natural gas and the heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then, introduce the coal tar into the reaction furnace. Under high-temperature conditions, it rapidly cracks to generate carbon black and flue gas. Note: The ratio of the introduced air to coal tar is 0.5:1.

[0177] (3) Introduce cooling water into the reaction furnace to rapidly reduce its temperature and terminate the reaction.

[0178] (4) When the temperature of the reaction furnace drops to 250 °C, an aqueous solution mixed with sodium polyacrylate is introduced into the reaction furnace in a ratio of 0.33:1 by mass to the coal tar, so that the temperature rapidly decreases and the super-dispersant coats the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulated by a dry granulation method to obtain carbon black pellets. Among them, the Mn of sodium polyacrylate is approximately 5000 and the concentration is 15 wt%; the structure of the dispersant is as follows:

[0179]

[0180] (5) The prepared carbon black is dried in a vacuum oven at 100 °C for 6 h, and the bottle-grade PET resin powder is dried in a vacuum oven at 130 °C for 6 h; the moisture content reaches below 500 ppm.

[0181] (6) Then, the dried PET powder and carbon black are blended evenly in a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled pelletizing to obtain PET masterbatch.

[0182] (7) Put the masterbatch into a vacuum oven at 150 °C and dry it for 10 h. After the moisture content drops below 50 ppm, mix it evenly with fiber-grade PET spinning chips at a mass ratio of 1:40, and melt-spin to obtain the solution-dyed polyester fiber.

[0183] Example 15

[0184] (1) First, preheat the air and coal tar. Heat the air to 800 °C through an air heater and send it into the reaction furnace; then preheat the coal tar to 300 °C and then send it into the reaction furnace. The introduced air and coal tar serve as reaction raw materials.

[0185] (2) Pass natural gas and the heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then pass the coal tar into the reaction furnace. Under high-temperature conditions, it quickly cracks to form carbon black and flue gas. Note: The ratio of the introduced air to coal tar is 0.5:1.

[0186] (3) Pass cooling water into the reaction furnace to quickly reduce its temperature and terminate the reaction.

[0187] (4) When the temperature of the reaction furnace drops to 250 °C, pass the aqueous solution mixed with sodium polyacrylate into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, so that the temperature quickly drops, and the superdispersant wraps around the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulation is carried out by dry granulation to obtain carbon black pellets. Among them, the Mn of sodium polyacrylate is approximately 1000 and the concentration is 15 wt%; the structure of the dispersant is as follows:

[0188]

[0189] (5) Put the prepared carbon black into a vacuum oven at 100 °C for drying treatment for 6 h, and put the bottle-grade PET resin powder into a vacuum oven at 130 °C for drying treatment for 6 h; the moisture content reaches below 500 ppm.

[0190] (6) Then blend the dried PET powder and carbon black evenly at a mass ratio of 70:30, and successively go through processes such as melt extrusion by a twin-screw extruder and water-cooling granulation to obtain the PET masterbatch.

[0191] (7) Put the masterbatch into a vacuum oven at 150 °C and dry it for 10 h. After the moisture content drops below 50 ppm, mix it evenly with fiber-grade PET spinning chips at a mass ratio of 1:40, and melt-spin to obtain the solution-dyed polyester fiber.

[0192] Example 16

[0193] (1) First, preheat the air and coal tar. Heat the air to 800 °C through an air heater and send it into the reaction furnace. Then, preheat the coal tar to 300 °C and subsequently send it into the reaction furnace. The introduced air and coal tar serve as reaction raw materials.

[0194] (2) Introduce natural gas and the heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then, introduce the coal tar into the reaction furnace. Under high-temperature conditions, it rapidly cracks to form carbon black and flue gas. Note: The ratio of the introduced air to coal tar is 0.5:1.

[0195] (3) Introduce cooling water into the reaction furnace to rapidly reduce its temperature and terminate the reaction.

[0196] (4) When the temperature of the reaction furnace drops to 250 °C, introduce an aqueous solution (concentration of 15 wt%) of ammonium polyacrylate (Mn≈5000) into the reaction furnace, which rapidly reduces the temperature and enables the hyperdispersant to coat the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter and granulated by dry granulation to obtain carbon black pellets. Among them, the Mn of ammonium polyacrylate is approximately 5000, and the concentration is 15 wt%. The structure of the dispersant is as follows:

[0197]

[0198] (5) Place the prepared carbon black in a vacuum oven at 100 °C for drying treatment for 6 h, and place the bottle-grade PET resin powder in a vacuum oven at 130 °C for drying treatment for 6 h. The moisture content reaches below 500 ppm.

[0199] (6) Then, blend the dried PET powder and carbon black evenly at a mass ratio of 70:30, and successively pass through processes such as melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch.

[0200] (7) Place the masterbatch in a vacuum oven at 150 °C and dry for 10 h. When the moisture content drops below 50 ppm, mix it evenly with fiber-grade PET spinning chips at a mass ratio of 1:40 and melt-spin to obtain solution-dyed polyester fiber.

[0201] Comparative Example 1

[0202] (1) First, preheat the air and coal tar. Heat the air to 800 °C through an air heater and send it into the reaction furnace. Then, preheat the coal tar to 300 °C and subsequently send it into the reaction furnace. The introduced air and coal tar serve as reaction raw materials.

[0203] (2) Feed natural gas and heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then feed coal tar into the reaction furnace. Under high-temperature conditions, it rapidly cracks to form carbon black and flue gas. Note: The ratio of the air fed in to the coal tar is 0.5:1;

[0204] (3) Feed cooling water into the reaction furnace to rapidly reduce its temperature and terminate the reaction;

[0205] (4) When the temperature of the reaction furnace drops to 250 °C, feed an aqueous solution of styrene maleic anhydride dispersant (concentration 15 wt%) into the reaction furnace to rapidly reduce the temperature and enable the hyperdispersant to coat the surface of the carbon black. The cooled carbon black and flue gas are separated and collected by a bag filter, and granulation is carried out by the dry granulation method to obtain carbon black pellets. Among them, the Mn of pure styrene maleic anhydride dispersant is approximately 25000, and the concentration is 15 wt%; the structure of the dispersant is as follows:

[0206]

[0207] (5) Place the prepared carbon black in a vacuum oven at 100 °C for drying treatment for 6 h, and place the bottle-grade PET resin powder in a vacuum oven at 130 °C for drying treatment for 6 h; the moisture content reaches below 500 ppm;

[0208] (6) Then blend the dried PET powder and carbon black evenly at a mass ratio of 70:30, and successively pass through processes such as melting and extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch;

[0209] (7) Place the masterbatch in a vacuum oven at 150 °C for drying for 10 h. When the moisture content drops below 50 ppm, mix it evenly with fiber-grade PET spinning chips at a mass ratio of 1:40 and carry out melt spinning to obtain solution-dyed polyester fiber.

[0210] Comparative Example 2

[0211] (1) First, preheat the air and preheat the coal tar. Heat the air to 800 °C by an air heater and feed it into the reaction furnace; then preheat and raise the temperature of the coal tar to 300 °C, and then feed it into the reaction furnace. The air and coal tar fed in are used as reaction raw materials;

[0212] (2) Feed natural gas and heated air into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then feed coal tar into the reaction furnace. Under high-temperature conditions, it rapidly cracks to form carbon black and flue gas. Note: The ratio of the air fed in to the coal tar is 0.5:1;

[0213] (3) Feed cooling water into the reaction furnace to rapidly reduce its temperature and terminate the reaction;

[0214] (4) When the temperature of the reaction furnace drops to 250 °C, the aqueous solution mixed with sodium lignosulfonate is introduced into the reaction furnace at a ratio of 0.33:1 by mass to the coal tar, so that the temperature drops rapidly, and the hyperdispersant wraps around the surface of the carbon black. The carbon black and flue gas after cooling are separated and collected by a bag filter, and granulation is carried out by a dry granulation method to obtain carbon black particles. Among them, the concentration of the sodium lignosulfonate aqueous solution is 15 wt%.

[0215] (5) The prepared carbon black is dried in a vacuum oven at 100 °C for 6 h, and the bottle-grade PET resin powder is dried in a vacuum oven at 130 °C for 6 h; the moisture content reaches below 500 ppm.

[0216] (6) Then the dried PET powder and carbon black are blended evenly at a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch.

[0217] (7) The masterbatch is placed in a vacuum oven at 150 °C and dried for 10 h. The moisture content drops to below 50 ppm and is mixed evenly with fiber-grade PET spinning chips at a mass ratio of 1:40, and melt spinning is carried out to obtain the solution-dyed polyester fiber.

[0218] Comparative Example 3

[0219] (1) First, air preheating and coal tar preheating are carried out. The air is heated to 800 °C by an air heater and sent into the reaction furnace; then the coal tar is preheated to 300 °C and then sent into the reaction furnace. The introduced air and coal tar serve as reaction raw materials.

[0220] (2) Natural gas and the heated air are introduced into the reaction furnace for combustion to generate a high-temperature combustion gas stream at a temperature of 1700 °C. Then the coal tar is introduced into the reaction furnace, and under high-temperature conditions, it is rapidly cracked to form carbon black and flue gas. Note: The ratio of the introduced air to the coal tar is 0.5:1.

[0221] (3) Cooling water is introduced into the reaction furnace to rapidly reduce its temperature and terminate the reaction; the carbon black and flue gas after cooling are separated and collected by a bag filter, and granulation is carried out by a dry granulation method to obtain carbon black particles.

[0222] (4) The prepared carbon black is dried in a vacuum oven at 100 °C for 6 h, and the bottle-grade PET resin powder is dried in a vacuum oven at 130 °C for 6 h; the moisture content reaches below 500 ppm.

[0223] (5) Then the dried PET powder and carbon black are blended evenly at a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch.

[0224] (6) The masterbatch was placed in a vacuum oven at 150 °C and dried for 10 h. After the moisture content dropped below 50 ppm, it was mixed evenly with fiber-grade PET spinning chips at a mass ratio of 1:40, and melt-spun to obtain the solution-dyed polyester fiber.

[0225] Comparative Example 4

[0226] (1) Domestic carbon black Junxin Chemical HPC 005WB was taken and dried in a vacuum oven at 100 °C for 6 h. The bottle-grade PET resin powder was placed in a vacuum oven at 130 °C and dried for 6 h; the moisture content reached below 500 ppm.

[0227] (2) Then the dried PET powder and carbon black were blended evenly at a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled pelletizing to obtain the PET black masterbatch;

[0228] (3) The masterbatch was placed in a vacuum oven at 150 °C and dried for 10 h. After the moisture content dropped below 50 ppm, it was mixed evenly with fiber-grade PET spinning chips at a mass ratio of 1:40, and melt-spun to obtain the solution-dyed polyester fiber.

[0229] Comparative Example 5

[0230] (1) Imported carbon black Cabot BP5560 was taken and dried in a vacuum oven at 100 °C for 6 h. The bottle-grade PET resin powder was placed in a vacuum oven at 130 °C and dried for 6 h; the moisture content reached below 500 ppm.

[0231] (2) Then the dried PET powder and carbon black were blended evenly at a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled pelletizing to obtain the PET black masterbatch;

[0232] (3) The masterbatch was placed in a vacuum oven at 150 °C and dried for 10 h. After the moisture content dropped below 50 ppm, it was mixed evenly with fiber-grade PET spinning chips at a mass ratio of 1:40, and melt-spun to obtain the solution-dyed polyester fiber.

[0233] Comparative Example 6

[0234] Preparation method of polyester fiber raw filament without adding carbon black:

[0235] The fiber-grade PET spinning chips were dried until the moisture content dropped below 50 ppm, and melt-spun to obtain the polyester fiber raw filament without adding carbon black.

[0236] Comparative Example 7

[0237] (1) The preparation method is the same as that of Example 1, except that during the cooling process of carbon black, only water is used for cooling. Then the prepared carbon black is added to a sodium hydroxide solution for activation to obtain activated carbon black. The activated carbon black and a titanate coupling agent (isopropyltris(dioctylpyrophosphato)titanate (NDZ-201)) are stirred in isopropanol to form a homogeneous liquid. The mass ratio of carbon black, titanate coupling agent and isopropanol is 10:10:100. After stirring at 3000 r / min for 3 hours at 30 °C, a mixed solution is obtained. The mixed solution is transferred to a rotary evaporator and rotary evaporated at 45 °C until the solvent isopropanol is completely evaporated. Finally, the solid product is taken out and dried in a vacuum oven at 80 °C for 8 hours to obtain the self-dispersing carbon black modified with a titanate coupling agent, with the water content controlled below 500 ppm;

[0238] (2) Then the dried PET powder and carbon black are blended evenly in a mass ratio of 70:30, and successively passed through processes such as melt extrusion by a twin-screw extruder and water-cooled pelletizing to obtain a PET black masterbatch;

[0239] (3) The masterbatch is placed in a vacuum oven at 150 °C and dried for 10 h. After the water content drops below 50 ppm, it is mixed evenly with fiber-grade PET spinning chips in a mass ratio of 1:40, and melt-spun to obtain a dope-colored polyester fiber.

[0240] Table 1 Properties of the dope-colored polyester fibers prepared in the examples and comparative examples

[0241]

[0242]

[0243] From the test results of Examples 1-3, it can be seen that by modifying carbon black with a dispersant obtained by graft copolymerization of monohydroxy polyester and styrene maleic anhydride, the copolymers with higher molecular weights have better heat resistance and dispersibility, meeting the requirements of polyester spinning. Those with lower molecular weights are prone to decomposition at high temperatures, but the molecular weight should not be too high, otherwise crosslinking will occur in the system, leading to agglomeration. From the test results of Examples 4-5, it can be seen that when the grafting rate of monohydroxy polyester is relatively low, the dispersion performance is relatively poor. From the test results of Examples 6-7, it can be seen that when the concentration of the dispersant added is low, the filtration performance is slightly poor. This is because the dispersant is difficult to completely coat the carbon black, resulting in poor dispersion performance of the carbon black in polyester. However, when the dosage of the dispersant is too high, bridging agglomeration is easily induced in the polyester system. From the test results of Examples 8-10, it can be seen that the dispersion performance of the copolymer grafted with isobutanol-modified styrene maleic anhydride is poor in the polyester system. This is because the carbon chain of isobutanol is short and its lipophilicity is low, resulting in poor compatibility with polyester. From the test results of Examples 11-16, it can be seen that compared with the case where no dispersant is added for modification, the dispersion effect is improved to a certain extent when using polyvinylpyrrolidone or polyacrylic acid to modify carbon black in the polyester fiber system. Compared with Comparative Examples 1-5, by using the method in Examples 1-3, after the masterbatch prepared by modifying carbon black with a dispersant of monohydroxy polyester grafted styrene-maleic anhydride copolymer is mixed with polyester chips, the pressure filtration value is low, the spinnability is good, and the as-spun colored polyester fiber obtained has a high breaking strength.

[0244] The examples provided above are not intended to limit the scope covered by the present invention, nor are the described steps intended to limit the order of their execution. Obvious improvements made by those skilled in the art in combination with the existing well-known common knowledge also fall within the protection scope defined by the claims of the present invention.

Claims

1. A preparation method of modified carbon black, characterized in that, It includes the following steps: (1) Preheat air and coal tar as reaction raw materials; (2) Feed natural gas and preheated air into a reaction furnace for combustion, then feed the preheated coal tar into the reaction furnace to pyrolyze and generate carbon black and flue gas; Feed water into the reaction furnace to lower its temperature and terminate the reaction; (3) Feed an aqueous solution of a hyperdispersant into the reaction furnace, and finally separate the carbon black and the flue gas.

2. The method according to claim 1, wherein In step (3), the hyperdispersant is one or more of styrene-maleic anhydride copolymer type, polyvinylpyrrolidone type, and modified polyacrylic acid type.

3. The method according to claim 2, wherein The structural formula of the styrene-maleic anhydride copolymer type hyperdispersant is: Among them, R1 is one of OH, alkane hydroxyl, and polyester hydroxyl groups; R2 is one of OH, alkane hydroxyl, and polyester hydroxyl groups; m:n is 1:0.03 to 1:0.15; the Mn of the styrene-maleic anhydride copolymer type hyperdispersant is 10,000 to 40,000.

4. The method according to claim 3, characterized in that, When the alkane hydroxyl is of isobutanol type, the structure is as shown in formula (Ⅰ): When the polyester hydroxyl is of monohydroxy polycaprolactone type, the structure is as shown in formula (Ⅱ): Among them, R3 is H or an alkyl group with less than 5 carbon atoms, and x is an integer less than 10.

5. The method according to claim 2, characterized in that, The structural formula of the polyvinylpyrrolidone type hyperdispersant is: Among them, the Mn of the polyvinylpyrrolidone type hyperdispersant is 8,000 to 360,000.

6. The method according to claim 2, characterized in that, The structural formula of the modified polyacrylic acid type hyperdispersant is: Among them, R4 is one or more of sodium salt, ammonium salt, and potassium salt; the Mn of the modified polyacrylic acid type hyperdispersant is 1,000 to 5,000.

7. The method according to claim 1, characterized in that In step (3), the mass fraction of the aqueous solution of the hyperdispersant is 5% to 25%.

8. The carbon black prepared by the method according to any one of claims 1 to 7.

9. The application of the carbon black according to claim 8 in polyester fiber masterbatch and in polyester fiber for dope dyeing.

10. A dope-dyed polyester fiber, characterized in that, The preparation method includes the following steps: (1) Granulate the carbon black according to claim 8 by dry granulation to obtain carbon black granules, and dry the carbon black granules and bottle-grade PET resin powder; (2) Then blend the dried bottle-grade PET resin powder and carbon black granules evenly according to a mass ratio of 65 to 75:25 to 35, and successively carry out melt extrusion by a twin-screw extruder and water-cooled granulation to obtain PET black masterbatch; (3) Dry the PET black masterbatch until the water content is reduced to less than 50 ppm, and mix it evenly with fiber-grade PET spinning chips according to a mass ratio of 1:100 to 5:100, and carry out melt spinning to obtain polyester fiber for dope dyeing.

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