Carbon black and manufacturing method and application thereof

Abstract

The invention provides carbon black which is prepared by performing heat treatment on recovered carbon black. As the carbon black is prepared from recycled carbon black, the carbon black also belongs to environment-friendly carbon black.

Description

[Technical Field]

[0001] The present invention relates to a carbon black and its applications, particularly a low-volatile carbon black prepared from recycled carbon black and its applications. [Background Art]

[0002] According to statistics, about 120,000 tons of waste tires are generated in Taiwan, China every year, and about 10,000 tons of waste tires need to be processed per month on average. The processed waste tires are mainly used as auxiliary fuels and recycled raw materials, and can be pyrolyzed into oil and carbon black for reuse.

[0003] However, the carbon black obtained by pyrolysis (recycled carbon black) contains a large amount of impurities at present, such as zinc oxide, silica, etc., which makes the recycled carbon black can only be used as a low-grade filler with low economic value, thus affecting the recycling rate of waste tires. [Summary of the Invention]

[0004] In view of this, the object of the present invention is to provide a carbon black with low impurity content prepared from recycled carbon black.

[0005] Based on the above object, the present invention provides the following carbon black, preparation method of carbon black, uses of carbon black, and coatings or inks.

[0006] Item 1. A carbon black, which is prepared from recycled carbon black and satisfies the following conditions: a volatile content of less than 3.4% by weight.

[0007] Item 2. The carbon black according to Item 1, wherein the volatile content is 3.2% by weight or less.

[0008] Item 3. The carbon black according to Item 1 or 2, wherein the volatile content is greater than about 0% by weight to about 2.9% by weight.

[0009] Item 4. The carbon black according to Item 1, which further satisfies the following conditions: an oil absorption value of about 150 mL / 100 g or less.

[0010] Item 5. The carbon black according to Item 4, wherein the oil absorption value is about 140 mL / 100 g or less.

[0011] Item 6. The carbon black according to Item 4 or 5, wherein the oil absorption value is about 100 mL / 100 g to about 135 mL / 100 g.

[0012] Item 7. The carbon black according to Item 1, which further satisfies the following conditions: a nitrogen adsorption specific surface area of about 40 m 2 / g or more.

[0013] Item 8. The carbon black according to Item 7, wherein the nitrogen adsorption specific surface area is about 60 m 2 / g or more.

[0014] Item 9. The carbon black as described in Item 7 or 8, wherein the nitrogen adsorption specific surface area is about 65 m 2 / g to about 150 m 2 / g.

[0015] Item 10. The carbon black as described in any one of Items 1, 2, 4, 5, 7, and 8, which further satisfies the following condition: polycyclic aromatic hydrocarbon group of about 2 ppm or less.

[0016] Item 11. A carbon black, which is prepared from recycled carbon black and satisfies the following conditions: volatile matter of more than about 0 wt% to about 2.9 wt%; and at least one selected from the group consisting of: (1) oil absorption value of about 100 mL / 100 g to about 135 mL / 100 g, (2) nitrogen adsorption specific surface area of about 65 m 2 / g to about 150 m 2 / g, and (3) polycyclic aromatic hydrocarbon group of about 2 ppm or less.

[0017] Item 12. A method for preparing the carbon black as described in any one of Items 1 to 11, which includes: (1) providing recycled carbon black; and (2) performing heat treatment on the recycled carbon black.

[0018] Item 13. The method as described in Item 12, wherein the recycled carbon black is obtained by pyrolyzing tires.

[0019] Item 14. The method as described in Item 12 or 13, wherein the heat treatment is carried out at about 800 °C or higher.

[0020] Item 15. The method as described in Item 14, wherein the heat treatment lasts for about 10 minutes or more.

[0021] Item 16. The method as described in Item 12, which further includes: (3) modifying the heat-treated recycled carbon black.

[0022] Item 17. The method as described in Item 16, which is modified with an oxidizing agent.

[0023] Item 18. The method as described in Item 16 or 17, which is modified with ozone.

[0024] Item 19. A use of the carbon black as described in any one of Items 1 to 11, which is used for coatings or inks.

[0025] Item 20. A coating or ink, which contains the carbon black as described in any one of Items 1 to 11.

[0026] The present invention can effectively reduce the impurities in the recycled carbon black with a simple process, thereby enhancing the applicability and economic value of the recycled carbon black. Brief Description of the Drawings

[0027] Figure 1 For the X-ray diffraction (XRD) pattern of the recovered carbon black, where (a) is the recovered carbon black after heat treatment; (b) is the recovered carbon black before heat treatment. Detailed Description of the Invention

[0028] In the present invention, "between X and Y" is equivalent to "X to Y", and includes the end values X and Y.

[0029] In the present invention, the term "about" can be regarded as modifying a term or a numerical value so that it is not an absolute value, but it cannot be found in the prior art. In some embodiments, the term "about" covers values within 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% (including these values) or any intermediate range (such as ±2% to 6%) of the measured value. It includes at least the degree of expected experimental error, technical error and instrument error of the method, analysis or measured value.

[0030] The carbon black provided by the present invention is prepared from recovered carbon black and satisfies the following conditions: less than 3.4% by weight of volatile matter. In some embodiments, the volatile matter of the carbon black is 3.2% by weight or less. In some embodiments, the volatile matter of the carbon black is greater than about 0% by weight to about 2.9% by weight. The volatile matter (% by weight) of the carbon black can also be any of the following values or can be between any range formed by any two of the following values: about 2.9, about 2.6, about 2.3, about 2.0, about 1.7, about 1.4, about 1.1, about 0.8, about 0.5, about 0.1, about 0.01. For example: in some embodiments, the volatile matter is between about 0.01 and about 0.8% by weight; in some other embodiments, the volatile matter is between about 1.4 and about 2.9% by weight.

[0031] The carbon black provided by the present invention can further satisfy the following conditions: an oil absorption value of about 150 mL / 100 g or less. In some embodiments, the oil absorption value is about 140 mL / 10 s g or less. In some embodiments, the oil absorption value is from about 100 mL / 100 g to about 135 mL / 100 g. In some embodiments, the oil absorption value can be any of the following values or can be between any range formed by any two of the following values: about 102, about 105, about 108, about 110, about 113, about 115, about 118, about 120, about 123, about 125, about 128, about 130, about 132 and about 134 mL / 100 g.

[0032] The carbon black provided by the present invention can further satisfy the following conditions: a nitrogen adsorption specific surface area of about 40 m 2 / g or more. In some embodiments, the nitrogen adsorption specific surface area is about 60 m 2 / g or more. In some embodiments, the nitrogen adsorption specific surface area is about 65 m 2 / g to about 150 m 2 / g. In some embodiments, the nitrogen adsorption specific surface area can be any value above the following, or can also be between the ranges formed by any two of the following values: about 67, about 69, about 70, about 75, about 80, about 85, about 90, about 95, about 100, about 105, about 110, about 115, about 120, about 125, about 130, about 135, about 140, about 145 and about 150 m 2 / g.

[0033] The carbon black provided by the present invention can further meet the following conditions: polycyclic aromatic hydrocarbons (PAHs) of about 2 ppm or less. In some embodiments, the content of polycyclic aromatic hydrocarbons can be any value below the following, or can also be between the ranges formed by any two of the following values: about 2, about 1.5, about 1.0, about 0.5 and about 0 ppm. In another embodiment, the content of 15PAHs in the carbon black provided by the present invention is between about 0 and about 2 ppm, for example: between about 0 and about 1.5; wherein, 15PAHs refers to the following 15 polycyclic aromatic hydrocarbons: Benzo[a]pyrene, Benzo[e]pyrene, Benzo[a]anthracene, Benzo[b]fluoranthene, Benzo[j]fluoranthene, Benzo[k]fluoranthene, (Chrysene), Dibenzo[a,h]anthracene, Benzo[g,h,i]perylene, Indeno[1,2,3-cd]pyrene, Anthracene, fluoranthene, phenanthrene, pyrene, Naphthalene.

[0034] In some embodiments, the carbon black provided by the present invention meets the following conditions: volatile matter greater than about 0 wt% to about 2.9 wt%; and oil absorption value of about 100 mL / 100 g to about 135 mL / 100 g. In other embodiments, the carbon black meets the following conditions: volatile matter greater than about 0 wt% to about 2.9 wt%; oil absorption value of about 100 mL / 100 g to about 135 mL / 100 g; and about 65 m2 from about 0 g to about 150 m 2 / g of nitrogen adsorption specific surface area.

[0035] In some embodiments, the carbon black provided by the present invention meets the following conditions: a volatile content greater than about 0 wt% to about 2.9 wt%; and about 65 m 2 / g to about 150 m 2 / g of nitrogen adsorption specific surface area. In other embodiments, the carbon black meets the following conditions: a volatile content greater than about 0 wt% to about 2.9 wt%; about 65 m 2 / g to about 150 m 2 / g of nitrogen adsorption specific surface area; and a polycyclic aromatic hydrocarbon group of about 2 ppm or less.

[0036] In some embodiments, the carbon black provided by the present invention meets the following conditions: a volatile content greater than about 0 wt% to about 2.9 wt%; and a polycyclic aromatic hydrocarbon group of about 2 ppm or less. In other embodiments, the carbon black meets the following conditions: a volatile content greater than about 0 wt% to about 2.9 wt%; an oil absorption value of about 100 mL / 100 g to about 135 mL / 100 g; and a polycyclic aromatic hydrocarbon group of about 2 ppm or less.

[0037] In some embodiments, the carbon black provided by the present invention meets the following conditions: a volatile content greater than about 0 wt% to about 2.9 wt%; an oil absorption value of about 100 mL / 100 g to about 135 mL / 100 g; about 65 m 2 / g to about 150 m 2 / g of nitrogen adsorption specific surface area; and a polycyclic aromatic hydrocarbon group of about 2 ppm or less.

[0038] In some embodiments, the carbon black provided by the present invention satisfies the following conditions: the X-ray diffraction (XRD) pattern has the following three characteristic peaks at the 2θ angular position: approximately 28° (e.g., 28.38 ± 0.2), approximately 47° (e.g., 47.26 ± 0.2), and approximately 56° (e.g., 56.08 ± 0.2). In some embodiments, the carbon black provided by the present invention satisfies the following conditions: the XRD pattern has the following four characteristic peaks at the 2θ angular position: approximately 28° (e.g., 28.38 ± 0.2), approximately 47° (e.g., 47.26 ± 0.2), approximately 56° (e.g., 56.08 ± 0.2), and approximately 69° (e.g., 69.08 ± 0.2). In some embodiments, the carbon black provided by the present invention satisfies the following conditions: the XRD pattern has the following five characteristic peaks at the 2θ angular position: approximately 28° (e.g., 28.38 ± 0.2), approximately 47° (e.g., 47.26 ± 0.2), approximately 56° (e.g., 56.08 ± 0.2), approximately 69° (e.g., 69.08 ± 0.2), and approximately 76° (e.g., 76.37 ± 0.2).

[0039] In some embodiments, the carbon black provided by the present invention has an XRD pattern substantially as Figure 1 (a) shown.

[0040] In some embodiments, the carbon black provided by the present invention satisfies the following conditions: the content of oxygen-containing functional groups measured by X-ray photoelectron spectroscopy (XPS) is about 70% or less. In some embodiments, the content of oxygen-containing functional groups can be any of the following values or can be within the range formed by any two of the following values: 68, 64, 59, 54, 49, 44, 39, 35, 30, 25, 20, 15, 10, 5, 0.

[0041] In some embodiments, the carbon black provided by the present invention satisfies the following conditions: the content of carbon-carbon bonds (C-C) measured by XPS is about 30% or more. In some embodiments, the content of carbon-carbon bonds can be any of the following values or can be within the range formed by any two of the following values: 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100.

[0042] In some embodiments, the carbon black provided by the present invention satisfies the following condition: the content of carbon-oxygen single bond (C-O) measured by XPS is about 40% or less. In some embodiments, the content of the carbon-oxygen single bond can be any of the following values or less, or can also be within the range formed by any two of the following values: 38, 36, 34, 32, 30, 28, 26, 24, 22, 20, 15, 10, 5, 0.

[0043] In some embodiments, the carbon black provided by the present invention satisfies the following condition: the content of carbon-oxygen double bond (C=O) measured by XPS is about 20% or less. In some embodiments, the content of the carbon-oxygen double bond can be any of the following values or less, or can also be within the range formed by any two of the following values: 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 5, 0.

[0044] In some embodiments, the carbon black provided by the present invention satisfies the following condition: the content of carboxyl group (COOH) measured by XPS is about 1% or more. In some embodiments, the carboxyl group content can be any of the following values or more, or can also be within the range formed by any two of the following values: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20.

[0045] The present invention also provides a method for manufacturing the aforementioned carbon black, which includes: providing recycled carbon black and performing heat treatment on the recycled carbon black. The obtained carbon black can not only satisfy the aforementioned volatile matter properties, but can also satisfy the properties of having at least one of the aforementioned oil absorption value, nitrogen adsorption specific surface area, and polycyclic aromatic hydrocarbon group or any combination thereof.

[0046] In the present invention, the recycled carbon black includes but is not limited to: recycled carbon black purchased from the market, recycled carbon black obtained from tires using known processes. For example, the recycled carbon black can be prepared by the following method: crushing waste tires; and performing pyrolysis on the crushed waste tires to obtain recycled carbon black. In some embodiments, a catalyst can be added to the crushed waste tires first and then pyrolysis is performed. The pyrolysis can be carried out at a temperature of about 500°C or less, or can also be within the range formed by any two of the following values: about 350°C, about 375°C, about 400°C, about 425°C, about 450°C, about 475°C.

[0047] In the present invention, the heat treatment of the recycled carbon black can be carried out at a temperature of about 800 °C or higher, or can also be within the range formed by any two of the following values: about 825 °C, about 850 °C, about 875 °C, about 900 °C, about 925 °C, about 950 °C, about 975 °C, about 1000 °C and about 1025 °C. The time of the heat treatment depends on the temperature of the heat treatment. Generally speaking, it can last for about 10 minutes or more, or can also be within the range formed by any two of the following values: about 20 minutes, about 30 minutes, about 40 minutes, about 50 minutes. The heat treatment can be carried out in air or can also be carried out in an inert gas (such as nitrogen). The heat treatment can be carried out in a high-temperature furnace, a microwave device or other devices capable of performing high-temperature heat treatment.

[0048] The method for manufacturing carbon black provided by the present invention can further include: modifying the heat-treated recycled carbon black to further obtain modified recycled carbon black. In some embodiments, the modification is an oxidation reaction. For example: in some embodiments, the modification is carried out with an oxidizing agent; in other embodiments, the modification is carried out with ozone. The time of the modification depends on the user's needs. Generally speaking, it can last for about 20 minutes or more, or can also be within the range formed by any two of the following values: about 40 minutes, about 60 minutes, about 80 minutes, about 100 minutes, about 120 minutes. For example: in some embodiments, the modification time is between about 40 and about 60 minutes; in other embodiments, the modification time is between about 80 and about 120 minutes.

[0049] The carbon black provided by the present invention can be used in coatings, inks or other coating applications (such as films). The carbon black can form a coating on a substrate by known coating methods. In some embodiments, the carbon black is incorporated into the ink for electrostatic printing or inkjet printing. In other embodiments, the carbon black is incorporated into the coating for coating.

[0050] [Heat-treated recycled carbon black]

[0051] Manufacturing Example 1: Manufacture of Carbon Black 1

[0052] Place the quartz crucible in a high-temperature furnace and bake it at 950 °C for 10 minutes to remove impurities in the crucible. Then, add 20.0 g of recycled carbon black PB-365 (Enrestec, Huantuo Technology) to the crucible, put it into a high-temperature furnace (DENG YNG DFH-20) and heat it at 950-1000 °C for 30 minutes to 1 hour for heat treatment. After the heat treatment is completed, place the quartz crucible at room temperature to cool, and carbon black 1 can be obtained.

[0053] Manufacturing Example 2: Manufacture of Carbon Black 2

[0054] Except that the heat treatment is carried out using a microwave device, carbon black 2 is obtained by the same method as in Manufacturing Example 1.

[0055] [Modified recycled carbon black]

[0056] Production Examples 3 and 4: Carbon black 3 and Carbon black 4

[0057] According to the conditions shown in Table 1, the aforementioned Carbon black 1 was modified using the carbon material post-modification treatment system disclosed in Taiwan Patent No. I796678B of China, and Carbon black 3 and Carbon black 4 can be obtained. The content of Taiwan Patent No. I796678B of China is incorporated herein by reference in its entirety.

[0058] Table 1

[0059] Table 2 shows the nitrogen adsorption specific surface area (nitrogen adsorption method, NSA), oil absorption number (OAN), and volatile content of the recycled carbon black and the carbon blacks of Production Examples 1 to 4. The measurement items listed in Table 2 were carried out in the following manner:

[0060] [NSA]

[0061] The specific surface area of the carbon black was measured according to ASTM D6556. The gas pressure of gas adsorption and desorption on the surface of the carbon black and the pore diameter at a constant temperature was measured, and the total surface area of the outer surface area and the inner surface area was measured using the nitrogen surface area according to the BET theoretical formula. The specific surface area was calculated using the cross-sectional area of gas molecules, the volume of gas molecules, and the sample weight. P is the pressure, P0 is the saturation pressure, V a Total absorption volume, C is the BET constant, V m Volume of gas required to form a monolayer.

[0062] [OAN]

[0063] The OAN of the carbon black was measured according to ASTM D2414. A certain amount of carbon black was weighed, and titrated with white mineral oil with a density of 1.042 - 1.047 g / cm 3 to the end point, and the absorption value was calculated based on the weight of the carbon black sample and the titration amount, and substituted into the following formula to obtain the OAN value. D: Absorption value of white mineral oil (petroleum) for carbon soot, V: Volume of white mineral oil (petroleum) consumed, M: Sample weight

[0064] [Volatile content]

[0065] Measure the organic compounds (including but not limited to residual oil, binder, surface functional groups, etc.) released by carbon black when baked at 950 °C for 7 minutes. Measure the weight of the crucible before and after carbon black burning, and calculate the loss percentage to know.

[0066] Table 2 PB-365 Production Example 1 Production Example 2 Production Example 3 Production Example 4 <![CDATA[NSA(m 2 / g)]]> 66.1 67.9 66.2 68.2 70.2 OAN (mL / 100g) 97.3 129.2 116.3 102.8 124.5 Volatile matter (wt%) 3.45 0.41 0.30 1.77 2.64

[0067] As shown in Table 2, the heat-treated recycled carbon black (Production Examples 1 and 2) has lower volatile matter than the recycled carbon black only pyrolyzed, indicating that the present invention can indeed significantly reduce the impurity content of organic compounds in the recycled carbon black through heat treatment to improve its purity. The experimental results of the modified recycled carbon black (Production Examples 3 and 4) show that the high-purity carbon black (Production Examples 1 and 2) after heat treatment can be further modified according to user needs to obtain desired properties, such as polarity, dispersibility, light absorption, colorability, etc. Among them, because the surface of the carbon black after modification has oxygen-containing functional groups, the modified recycled carbon black (Production Example 3) has higher volatile matter than the recycled carbon black only heat-treated (Production Examples 1 and 2), and the longer the modification time (Production Example 4), the more oxygen-containing functional groups accumulate on the surface of the carbon black, and the volatile matter will increase again.

[0068] Table 3 shows the content test of polycyclic aromatic hydrocarbons in the recycled carbon black (PB-365) before heat treatment, the recycled carbon black after heat treatment (Production Example 1), and the modified recycled carbon black (Production Example 3). It is detected by a gas chromatography-mass spectrometer (Agilent 5977B GC / MSD) according to the GS PAH standard 2019 version (AfPS GS 2019:01 PAK). It shows that the 15PAHs content of the recycled carbon black after heat treatment and the modified recycled carbon black is 0, indicating that the 15PAHs in the recycled carbon black can be reduced to less than 0.2 ppm after heat treatment.

[0069] Table 3 <Note>: 1. MDL: Detection limit value. 2. ND: Not detected.

[0070] Table 3-1 shows the results of measuring recycled carbon black (PB-365), the carbon black of Production Example 1, and the carbon black of Production Example 3 using XPS (PHI Quanta II, ULVAC-PHI Inc). The C1s binding energy of the XPS spectrum was calibrated with a standard value of 285.6 eV, and then the contents of carbon-carbon bonds and each oxygen-containing functional group were obtained through curve fitting (the binding energies corresponding to each functional group during fitting were: C-C bond = 285.4 eV, C-O bond = 286 eV, C=O bond = 287 eV, COOH bond = 289.6 eV; the total area of all peaks after fitting was 100%).

[0071] Table 3-1 shows that the content of oxygen-containing functional groups in the carbon black of Production Example 1 and Production Example 3 is 70% or less, which is lower than that of the recycled carbon black (PB-365) without heat treatment, proving that the content of organic compound impurities in the recycled carbon black (Production Example 1) after heat treatment has been significantly reduced compared to the recycled carbon black (PB-365) without heat treatment; it also proves that oxygen-containing functional groups have accumulated on the surface of the modified recycled carbon black (Production Example 3) due to the oxidation reaction, and it has a higher content of oxygen-containing functional groups than the recycled carbon black (Production Example 1) only after heat treatment, but is still lower than the recycled carbon black (PB-365) without heat treatment.

[0072] Table 3-1

[0073] Figure 1 is the X-ray diffraction (XRD) pattern of recycled carbon black, where (a) is the recycled carbon black after heat treatment (Production Example 1); (b) is the recycled carbon black before heat treatment (PB-365). Figure 1 shows that the heat-treated recycled carbon black has characteristic peaks of crystalline silicon (Si) at 2θ positions of 28.38°, 47.26°, 56.08°, 69.08°, and 76.37° (the source is the ash in waste tires), and has characteristic peaks of amorphous silica (SiO2) at 2θ positions of 15-30°. Figure 1 shows that compared with the recycled carbon black without heat treatment, the content of pure silicon in the heat-treated recycled carbon black increases (the peak width of the characteristic peak is narrower and the intensity is higher).

[0074] Example: Manufacture of metallic paint

[0075] The components listed in Table 4 were mixed in the indicated proportions, where the carbon black used in Example 1 was the modified recycled carbon black (Production Example 3) respectively, and the commercially available virgin carbon black (Mitsubishi Chemical MA100; NSA was 110m 2 / g, OAN of 100 mL / 100 g and volatile matter of 1.5 wt%) was used as Comparative Example 1. After mixing, the mixture was made uniform by a high-speed mixer, and the resulting slurry was added to a paint mixer (RADIARed Devil 1400-0H) for grinding. The fineness was judged every hour in terms of fineness until the fineness was less than 10 microns. Then, a solvent was added to adjust the viscosities of Example 1 and Comparative Example 1 to the same range (i.e., the viscosity was FC#4 60 ± 10 seconds), thereby obtaining metallic paints.

[0076] Table 4 Metallic paint composition Parts by weight A136-70 (solid content 70%) (Dainippon Polymer) 114 Crosslinking agent Melamine MR-625 (solid content 76%) (Chang Chun Chemical) 20 Dispersant BYK-118 (solid content 80%) 1.5 Carbon black 15 Defoamer BYK-057 (solid content 40%) 0.5 Leveling agent POLYFLOW No.90 (Kyoeisha Chemical) 3 Diluent 45 <Note> Thinner: BCS / Xylene / #150 = 40 / 40 / 20, where #150 refers to Paint Solvent - 150 (High- Flash Aromatic Naphtha-150).

[0077] The metallic paints were coated on masking filter paper (Table 5) and tinplate (Table 6) with a wire bar and baked at 130 °C for 30 minutes. Then, the gloss was measured with a gloss meter (Dr Lange REFO 3), and the blackness and hue were measured with a color difference meter (X-rite Ci7600). When measuring the blackness and hue, the SCE* (specular component excluded) mode was used for measurement to exclude specular reflected light and thus truly present the color seen by the human eye. The test results are shown in Tables 5 and 6 respectively, where △E * ab =

[0078] Table 5

[0079] Table 6

[0080] From the results in Tables 5 and 6, it can be seen that the metallic paints of Example 1 and Comparative Example 1 have the same blackness (My) and similar chromaticities (△E * ab ) on different substrates, which shows that although the modified carbon black (Production Example 3) of the present invention is prepared from recycled carbon black, it has properties close to those of commercially available virgin carbon black (Comparative Example 1). Thus, the modified carbon black prepared from recycled carbon black can be directly used to replace the commercially available virgin carbon black in the original formulation with minimal modification to the original formulation of the paint or ink.

[0081] In summary, the present invention can effectively purify recycled carbon black by subjecting it to heat treatment, and obtain modified carbon black that can replace commercially available virgin carbon black through modification, thereby enhancing the application value and economic value of recycled carbon black. Since the carbon black of the present invention is made from recycled carbon black, the carbon black of the present invention also belongs to an environmentally friendly carbon black and has great application value.

[0082] However, the above are only preferred embodiments of the present invention, and should not be used to limit the scope of implementation of the present invention. That is, as long as simple equivalent changes and modifications are made according to the scope of the patent application of the present invention and the content of the invention description, they still fall within the scope covered by the patent of the present invention.

Claims

1. A carbon black which is prepared by heat-treating recycled carbon black and satisfies the following conditions: a volatile content of less than 3.4% by weight and polycyclic aromatic hydrocarbons of about 2 ppm or less.

2. The carbon black according to claim 1, wherein the volatile content is 3.2% by weight or less.

3. The carbon black according to claim 1 or 2, wherein the volatile content is greater than about 0% by weight to about 2.9% by weight.

4. The carbon black according to claim 1, which further satisfies the following condition: an oil absorption value of about 150 mL / 100 g or less.

5. The carbon black according to claim 4, wherein the oil absorption value is about 140 mL / 100 g or less.

6. The carbon black according to claim 4 or 5, wherein the oil absorption value is about 100 mL / 100 g to about 135 mL / 100 g.

7. The carbon black as described in claim 1 further satisfies the following condition: a nitrogen adsorption specific surface area of more than about 40 m 2 / g.

8. The carbon black according to claim 7, wherein the nitrogen adsorption specific surface area is about 60 m 2 / g or more.

9. The carbon black according to claim 7 or 8, wherein the nitrogen adsorption specific surface area is about 65 m 2 / g to about 150 m 2 / g.

10. A carbon black is prepared by heat-treating recycled carbon black and satisfies the following conditions: a volatile content greater than about 0 wt% to about 2.9 wt%; polycyclic aromatic hydrocarbons of about 2 ppm or less; and at least one selected from the group consisting of: (1) an oil absorption value of about 100 mL / 100 g to about 135 mL / 100 g, and (2) a nitrogen adsorption specific surface area of about 65 m 2 / g to about 150 m 2 / g.

11. A method for preparing carbon black, which comprises: (1) providing recycled carbon black; and (2) heat-treating the recycled carbon black.

12. The method according to claim 11, wherein the recycled carbon black is obtained by pyrolyzing tires.

13. The method according to claim 11 or 12, wherein the heat treatment is carried out at about 800 °C or higher.

14. The method according to claim 13, wherein the heat treatment lasts for about 10 minutes or longer.

15. The method according to claim 11, which further comprises: (3) modifying the heat-treated recycled carbon black.

16. The method according to claim 15, wherein the modification is carried out with an oxidizing agent.

17. The method according to claim 15 or 16, wherein the modification is carried out with ozone.

18. Use of a carbon black according to any one of claims 1 to 10 for coatings or inks.

19. A coating or ink which comprises a carbon black according to any one of claims 1 to 10.

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