Method for modifying waste tire pyrolysis carbon black and carbon black obtained thereby

Abstract

The application discloses a modification method of waste tire thermal cracking carbon black and the obtained carbon black. The method comprises the following steps: (1) high-temperature treatment of thermal cracking carbon black; (2) adding the thermal cracking carbon black after high-temperature treatment in step (1) into an acid solution, stirring to obtain an acid washing thermal cracking carbon black water suspension, and drying after water washing to obtain acid washing thermal cracking carbon black; and (3) mixing the acid washing thermal cracking carbon black obtained in step (2) with a silane coupling agent and performing heat treatment to obtain modified thermal cracking carbon black. The modification method reduces the ash content of the thermal cracking carbon black, enhances the surface activity of the thermal cracking carbon black, improves the reinforcing performance of the thermal cracking carbon black in rubber, increases the use amount of the thermal cracking carbon black, and makes the thermal cracking carbon black have a wider application.

Description

Technical Field

[0001] This invention relates to the field of modification technology of pyrolysis carbon black from waste tires, specifically to a method for modifying pyrolysis carbon black from waste tires and the resulting carbon black. Background Technology

[0002] With the development of my country's social economy, automobiles are increasingly integrated into production and daily life, and the usage of tires is becoming increasingly large. However, this has brought about a serious problem of waste tire disposal and reuse. Traditional methods such as direct landfill, tire retreading, and rubber powder production have problems such as environmental pollution, narrow applicability, and resource waste. The pyrolysis treatment of waste tires is considered an environmentally friendly and efficient method. While disposing of waste tires, it truly achieves "full utilization," obtaining high-value by-products, which is of great significance. Among them, pyrolysis carbon black, as an important by-product of the pyrolysis tire process, has long suffered from poor reinforcing properties, thus restricting the development of the entire pyrolysis industry.

[0003] Pyrolysis is the process of converting waste polymers (or biomass) into smaller molecule compounds and solid products at suitable temperatures in an oxygen-free or inert atmosphere. Research on pyrolysis began earlier abroad; in the 1970s, Kaminsky et al. at the University of Hamburg, Germany, began their research on the pyrolysis of waste polymers. Regarding pyrolysis carbon black, in the 1980s, Bouier J.M. of France discovered that pyrolysis carbon black contains high levels of ash and residual pyrolysis oil, resulting in poor reinforcing properties in rubber. Currently, pyrolysis carbon black directly obtained from the pyrolysis of waste tires generally requires modification treatment to restore its reinforcing properties before it can be used in tires, thereby increasing its added value and application range. However, whether it is ultrafine modification aimed at reducing particle size or simple modifier modification, although the reinforcing performance in rubber is improved, the improvement is limited and it is difficult to reach the level required by high-performance carbon black or national standards. In order to ensure product performance, a large amount of commercial carbon black can only be mixed in, which restricts the amount of pyrolysis carbon black used. In the past, acid washing modification was less efficient, and strong acid would greatly increase the surface activity of pyrolysis carbon black, making it easier for carbon black particles to agglomerate, reducing the dispersibility of carbon black in rubber, thus restricting the performance of carbon black rubber composites.

[0004] Therefore, there is an urgent need for a modification method that can simultaneously and effectively reduce the ash content of pyrolysis carbon black and avoid agglomeration problems. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method for modifying pyrolytic carbon black from waste tires and the resulting carbon black. The modification method of this invention includes: firstly, pretreating the sample at high temperature under a nitrogen atmosphere or vacuum; then, acid washing to reduce the ash content; and finally, grafting modification with a coupling agent. This modification method improves the reinforcing properties of pyrolytic carbon black in rubber, increases the amount of pyrolytic carbon black used, and enables pyrolytic carbon black to have wider applications.

[0006] One of the objectives of this invention is to provide a method for modifying pyrolytic carbon black from waste tires.

[0007] The method includes:

[0008] (1) High-temperature treatment of pyrolysis carbon black;

[0009] (2) Add the thermally pyrolyzed carbon black treated at high temperature in (1) to the acid solution and stir to obtain an aqueous suspension of acid-washed thermally pyrolyzed carbon black. After washing with water and drying, acid-washed thermally pyrolyzed carbon black is obtained.

[0010] (3) The acid-washed thermal pyrolysis carbon black obtained in (2) is mixed with a silane coupling agent and heat-treated to obtain the modified thermal pyrolysis carbon black.

[0011] In a preferred embodiment of the present invention,

[0012] In step (1),

[0013] High-temperature treatment is carried out under nitrogen atmosphere or vacuum conditions.

[0014] In a preferred embodiment of the present invention,

[0015] In step (1),

[0016] The high-temperature treatment temperature is 300-600℃, preferably 400-500℃, more preferably 450-500℃, and the high-temperature treatment time is 15min-1h, preferably 30min-40min.

[0017] In a preferred embodiment of the present invention,

[0018] In step (2),

[0019] The acid solution is one of nitric acid solution, hydrochloric acid solution, and sulfuric acid solution;

[0020] The concentration of the acid solution is 2 mol / L to 7 mol / L, preferably 3 mol / L to 5 mol / L.

[0021] In a preferred embodiment of the present invention,

[0022] In step (2),

[0023] The mass ratio of the thermally decomposed carbon black after high-temperature treatment to the acid solution is 1:5 to 1:20, preferably 1:8 to 1:19.5.

[0024] In a preferred embodiment of the present invention,

[0025] In step (2),

[0026] The stirring temperature is 50℃~80℃, and the stirring time is 30min~2h;

[0027] Wash with water until the pH reaches 5-6, then dry.

[0028] In a preferred embodiment of the present invention,

[0029] In step (3),

[0030] The silane coupling agent is a silane polymer containing polyether segments (the silane polymer containing polyether segments described in patent application 202111383364.9 is incorporated herein by reference in its entirety).

[0031] Silane polymers containing polyether segments have the following general formula:

[0032] R x Si y O z (OR1) w O(R2) m Q n ...Formula (I)

[0033] In formula (I), x is 2 to 12, preferably 2 to 6;

[0034] y is 2 to 12, preferably 2 to 6;

[0035] z is 2 to 12, preferably 2 to 6;

[0036] w is 2 to 24, preferably 2 to 12;

[0037] m is 1 to 6;

[0038] n can be 1 to 24, preferably 1 to 12;

[0039] R is a straight-chain or branched alkane or olefinic group of C3 to C36, preferably a straight-chain or branched alkane group of C3 to C18.

[0040] R1 is methyl or ethyl;

[0041] R2 is an aliphatic chain containing a polyether structure, with the structural formula R3-(C2H4O). k- where R3 is a saturated fatty chain of C3 to C18, and k is an integer from 3 to 9;

[0042] Q can be either S or SH.

[0043] The above-mentioned silane polymer is obtained by reacting components including a silane compound and a fatty alcohol polyoxyethylene ether. Preferably, the silane compound is selected from sulfur-containing silanes containing methoxy and / or ethoxy groups, and the fatty alcohol polyoxyethylene ether is selected from fatty alcohol polyoxyethylene ethers with a hydroxyl value of 95 to 180.

[0044] A method for preparing a silane polymer containing polyether segments includes heating and reacting components including a silane compound and a fatty alcohol polyoxyethylene ether to obtain the silane polymer containing polyether segments. Preferably, the preparation method specifically includes the following steps:

[0045] Step 1) The silane compound is added to a solvent and hydrolyzed to obtain a silane hydrolysate;

[0046] Step 2) The silane hydrolysate undergoes a polycondensation reaction to obtain silane polymers;

[0047] Step 3) The fatty alcohol polyoxyethylene ether is added to the silane polymer and heated to react, thereby obtaining the silane polymer containing polyether segments.

[0048] The aforementioned silane polymer containing polyether segments is prepared by a silane coupling agent containing methoxy or ethoxy groups commonly used in industry through a polycondensation reaction between silanols, and then reacted with fatty alcohol polyoxyethylene ethers.

[0049] In the above preparation method, in step 1):

[0050] The silane compound is selected from sulfur-containing silanes containing methoxy and / or ethoxy groups, specifically from at least one of compounds such as Si69, Si75, KH580, and KH590;

[0051] The solvent is selected from at least one of water and alcohol, preferably a mixed solvent of ethanol and water; the ratio of ethanol to water in the solvent is 1:50 to 50:1, preferably 1:20 to 20:1.

[0052] The ratio of the silane compound to the solvent is (1-100):1, preferably (1-50):1, and more preferably (1-10):1;

[0053] The hydrolysis temperature is 25–35°C, and the hydrolysis time is 1–5 hours.

[0054] The hydrolysis process also involves the addition of a pH adjuster, which is selected from at least one of hydrochloric acid, formic acid, acetic acid, sodium bicarbonate, and sodium carbonate, preferably from at least one of hydrochloric acid, acetic acid, and sodium bicarbonate; the pH adjuster adjusts the pH of the solution to 3-6.

[0055] In the above preparation method, in step 2), the temperature of the polycondensation reaction is 0-100℃, preferably 25-60℃; the time of the polycondensation reaction is 1-10 hours, preferably 3-5 hours.

[0056] In the above preparation method, in step 3):

[0057] The fatty alcohol polyoxyethylene ether is selected from fatty alcohol polyoxyethylene ethers with a hydroxyl value of 95 to 180;

[0058] The molar ratio of the fatty alcohol polyoxyethylene ether to the silane compound is (1-6):1, preferably (1-3):1;

[0059] The reaction temperature of the heating reaction is 100-150°C, preferably 110-130°C; the reaction time is 1-12 hours, preferably 1-6 hours.

[0060] A catalyst is also added to the heating reaction; wherein the catalyst is selected from titanate catalysts, preferably at least one of tetrabutyl titanate, tert-butyl titanate, and isopropyl titanate; the amount of catalyst used is 0.1-3% of the total amount of silane compound and fatty alcohol polyoxyethylene ether.

[0061] The heating reaction is carried out under inert gas protection; after the heating reaction, a vacuum treatment is required, wherein the vacuum temperature is 50-80℃, and the vacuum degree in the reaction vessel is maintained at -0.06 to -0.1 MPa.

[0062] In a preferred embodiment of the present invention,

[0063] In step (3),

[0064] The mass ratio of pickled pyrolysis carbon black to silane coupling agent is 8:1 to 15:1, preferably 10:1 to 13:1.

[0065] In a preferred embodiment of the present invention,

[0066] In step (3),

[0067] The heat treatment of pickled pyrolysis carbon black mixed with silane coupling agent involves mixing pickled pyrolysis carbon black with silane coupling agent and then heat-treating at 140℃~160℃ for 4~6 minutes.

[0068] Normally, for ease of operation, the mixing process in step (3) is preferably carried out in a high-speed mixer; the heat treatment process in step (3) is preferably carried out during the rubber compounding process, that is, in the internal mixer, the rubber compound is heat-treated at 140℃~160℃ for 4~6 minutes together.

[0069] A second objective of this invention is to provide a carbon black prepared by a method according to one objective of this invention.

[0070] The present invention can adopt the following specific technical solutions:

[0071] The method for modifying waste tire pyrolysis carbon black includes the following steps:

[0072] (1) The thermally decomposed carbon black is subjected to high-temperature treatment to prepare for subsequent steps.

[0073] (2) Acid washing and post-treatment of the pyrolysis carbon black obtained in step (1): Add the pyrolysis carbon black after high temperature treatment to the acid solution in proportion, stir at high speed at 50℃~80℃ for 30min~2h to obtain an aqueous suspension of acid-washed pyrolysis carbon black, wash repeatedly with water until the pH is 5~6, and dry to obtain acid-washed pyrolysis carbon black.

[0074] (3) The pickled pyrolysis carbon black obtained in step (2) is mixed with silane coupling agent in a high-speed mixer in a certain proportion, and the modified pyrolysis carbon black is obtained after heat treatment. The heat treatment of pickled pyrolysis carbon black and silane coupling agent is preferably carried out during the mixing process with rubber. The specific steps are as follows: 1) Add rubber, carbon black containing silane coupling agent, zinc oxide, and stearic acid in sequence in a mixer, and mix evenly at 50-60℃; 2) Heat treat the rubber compound at 140-160℃ for 4-6 minutes in a mixer and then discharge the rubber; 3) After the rubber compound cools to room temperature, place the rubber compound in a two-roll mill, add accelerator and sulfur, and mix evenly.

[0075] The main differences between waste tire pyrolysis carbon black and ordinary carbon black are as follows: 1. Morphological characteristics and particle size: Pyrolysis carbon black particles have blurred edges, irregular shapes, and larger and more uneven particle sizes; 2. Smaller BET specific surface area and poorer surface activity; 3. Excessively high impurity content, with ash content generally around 16-20%, mainly composed of metal oxides such as ZnO and non-metal oxides such as SiO2.

[0076] Compared with direct pickling, the method of high-temperature pretreatment followed by pickling can more efficiently reduce ash content and improve pickling efficiency; then, the coupling agent provided by this invention is used for modification, which can effectively improve the mechanical properties of the pyrolysis carbon black-rubber composite material.

[0077] The beneficial effects of this invention are as follows:

[0078] The method for modifying waste tire pyrolysis carbon black provided by this invention can improve pickling efficiency, significantly reduce ash content, and enhance the reinforcing properties of pyrolysis carbon black in rubber. Attached Figure Description

[0079] Figure 1 Electron micrograph of commercial carbon black N330;

[0080] Figure 2 Electron micrograph of unmodified pyrolysis carbon black;

[0081] Figure 3 Electron micrograph of thermally decomposed carbon black after being treated at 500℃ for 30 min in a nitrogen atmosphere;

[0082] Figure 4 This is an electron micrograph of acid-washed pyrolysis carbon black from Example 5;

[0083] Figure 5 Electron micrograph of thermally pyrolyzed carbon black directly washed with 5 mol / L hydrochloric acid. Detailed Implementation

[0084] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0085] All raw materials used in the examples are commercially available.

[0086] Table 1. Brand and source of some raw materials

[0087] name supplier Pyrolytic carbon black Commercially available Carbon Black N330 Degussa Carbon Black N660 Degussa sulfuric acid Commercially available hydrochloric acid Commercially available Nitric acid Commercially available

[0088] The testing instruments and conditions used in this embodiment are as follows:

[0089] Table 2. Test Standards / Conditions

[0090] Test Project Standards / Conditions Carbon black ash content test GB / T3780.10-2017 Vulcanization performance test GB / T9869 Mechanical testing GB / T528-2009 Hardness test of vulcanized rubber GB / T6031-1998

[0091] Preparation of silane coupling agents:

[0092] Silane coupling agent 1:

[0093] 10.86 g (0.02 mol) of silane coupling agent Si69 was added to a mixed solvent of ethanol and water in a ratio of 20:1, with the ratio of the mixed solvent to coupling agent Si69 being 1:5. Formic acid was added to adjust the pH to 3, and the mixture was hydrolyzed at 25°C for 1 hour to obtain a hydrolysate containing silanol groups. The hydrolyzed silane coupling agent containing hydroxyl groups was then polymerized at 25°C with stirring for 5 hours. Then, 11.64 g (0.02 mol) of fatty alcohol polyoxyethylene ether-9 (hydroxyl value 95–100) and 0.675 g of tetrabutyl titanate catalyst were added. The mixture was heated to 130°C and protected with nitrogen gas for 2.5 hours. Finally, the temperature was lowered to 80°C, and the system was purified for two hours under a vacuum of -0.08 MPa. The resulting silane coupling agent 1 is a compound containing the following general formula:

[0094] C 12 H 24 Si4O2(OC2H5)6O[(C2H4O)9C 12 H 25 ]2S8

[0095] Silane coupling agent 2

[0096] 10.86 g (0.02 mol) of silane coupling agent Si69 was added to a mixed solvent of ethanol and water in a ratio of 20:1, with the ratio of mixed solvent to coupling agent Si69 being 1:4. Acetic acid was added to adjust the pH to 3. Hydrolysis was carried out at 35°C for 1 hour to obtain a hydrolysate containing silanol groups. The hydroxyl-containing silane coupling agent obtained from the hydrolysis was then polymerized at 25°C with stirring for 5 hours. Then, 17.46 g (0.03 mol) of fatty alcohol polyoxyethylene ether-9 (hydroxyl value 95–100) and 0.85 g of tetrabutyl titanate catalyst were added. The mixture was heated to 130°C and protected with nitrogen gas for 2.5 hours. Finally, the temperature was lowered to 80°C, and the system was purified for two hours under a vacuum of -0.1 MPa. The resulting silane coupling agent 2 is a compound containing the following general formula: C 12 H 24 Si4O2(OC2H5)5O[(C2H4O)9C 12 H 25 3S8

[0097] Example 1

[0098] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. Under a nitrogen atmosphere, the muffle furnace was heated from room temperature at a rate of 10℃ / min to 400℃ and held at that temperature for 15 minutes, then cooled to room temperature. The pyrolysis carbon black treated at high temperature was added to a 3mol / L hydrochloric acid solution at a ratio of 1g carbon black to 10mL (10.5g) acid solution. The mixture was stirred at high speed at 60℃ for 1 hour. The mixture was repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 in a high-speed mixer.

[0099] The heat treatment process of pickled pyrolysis carbon black and silane coupling agent 1 is carried out during the mixing process with rubber. The specific operation steps are as follows: 1) Add rubber, pickled pyrolysis carbon black mixed with silane coupling agent 1, zinc oxide, and stearic acid to the internal mixer in sequence, and mix evenly at 55°C; 2) Heat treat the rubber compound at 150°C for 5 minutes in the internal mixer and then discharge the rubber; 3) After the rubber compound cools to room temperature, place the rubber compound in a two-roll mill, add accelerator and sulfur, and mix evenly; 4) Vulcanize the mixed rubber at 145°C to obtain vulcanized rubber; the formula is shown in Table 3, and the performance test results of the vulcanized rubber are shown in Table 5.

[0100] Table 3. Vulcanizate formulation

[0101]

[0102] Example 2

[0103] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. Under a nitrogen atmosphere, the muffle furnace was heated from room temperature at a rate of 10℃ / min to 500℃ and held at that temperature for 15 minutes, then cooled to room temperature. The pyrolysis carbon black treated at high temperature was mixed with 10 mL (10.5 g) of acid solution per 1 g of carbon black in a 3 mol / L hydrochloric acid solution and stirred at high speed at 60℃ for 1 hour. The mixture was repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and heat-treated.

[0104] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 1 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0105] Example 3

[0106] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. Under a nitrogen atmosphere, the muffle furnace was heated from room temperature at a rate of 10℃ / min to 500℃ and held at that temperature for 30 min, then cooled to room temperature. The high-temperature treated pyrolysis carbon black was mixed with 10 mL (10.5 g) of acid solution per 1 g of carbon black in a 3 mol / L hydrochloric acid solution and stirred at high speed at 60℃ for 1 h. The mixture was repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and heat-treated.

[0107] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 1 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0108] Example 4

[0109] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. The muffle furnace was heated from room temperature to 600℃ at a rate of 10℃ / min under a nitrogen atmosphere and held at that temperature for 1 hour. Then it was cooled to room temperature. The pyrolysis carbon black treated at high temperature was mixed with 10 mL (10.5 g) of acid solution per 1 g of carbon black in a 3 mol / L hydrochloric acid solution. The mixture was stirred at high speed at 60℃ for 1 hour. The mixture was washed repeatedly with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and heat-treated.

[0110] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 1 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0111] Example 5

[0112] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. Under a nitrogen atmosphere, the muffle furnace was heated from room temperature at a rate of 10℃ / min to 500℃ and held at that temperature for 30 minutes, then cooled to room temperature. The high-temperature treated pyrolysis carbon black was mixed with 10 mL (10.8 g) of acid solution per 1 g of carbon black in a 5 mol / L hydrochloric acid solution and stirred at high speed at 60℃ for 1 hour. The mixture was repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and heat-treated.

[0113] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 1 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0114] Example 6

[0115] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. The muffle furnace was heated from room temperature to 500℃ at a rate of 10℃ / min under a nitrogen atmosphere and held at that temperature for 30 min, and then cooled to room temperature. The pyrolysis carbon black treated at high temperature was added to a 5mol / L hydrochloric acid solution at a ratio of 8 mL (8.6 g) of acid solution per 1 g of carbon black. The solution was stirred at high speed at 60℃ for 1 h. The carbon black was repeatedly washed with water until the pH was 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and heat-treated.

[0116] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 1 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0117] Example 7

[0118] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. Under a nitrogen atmosphere, the muffle furnace was heated from room temperature at a rate of 10℃ / min to 500℃ and held at that temperature for 30 minutes, then cooled to room temperature. The high-temperature treated pyrolysis carbon black was mixed with 15 mL (16.2 g) of acid solution per 1 g of carbon black in a 5 mol / L hydrochloric acid solution and stirred at high speed at 60℃ for 1 hour. The mixture was repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and heat-treated.

[0119] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 1 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0120] Example 8

[0121] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. Under a nitrogen atmosphere, the muffle furnace was heated from room temperature at a rate of 10℃ / min to 500℃ and held at that temperature for 30 min, then cooled to room temperature. The pyrolysis carbon black treated at high temperature was mixed with 10 mL (10.8 g) of acid solution per 1 g of carbon black in a 5 mol / L hydrochloric acid solution. The mixture was stirred at high speed at 50℃ for 30 min. The mixture was repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and then heat-treated.

[0122] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 1 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0123] Example 9

[0124] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. The muffle furnace was heated from room temperature to 500℃ at a rate of 10℃ / min under a nitrogen atmosphere and held at that temperature for 30 minutes, and then cooled to room temperature. The high-temperature treated pyrolysis carbon black was mixed with 10 mL (10.8 g) of acid solution per 1 g of carbon black in a 5 mol / L hydrochloric acid solution and stirred at high speed at 80℃ for 2 hours. The mixture was repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and heat-treated.

[0125] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 1 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0126] Example 10

[0127] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. Under a nitrogen atmosphere, the muffle furnace was heated from room temperature at a rate of 10℃ / min to 500℃ and held at that temperature for 30 minutes, then cooled to room temperature. The high-temperature treated pyrolysis carbon black was mixed with 10 mL (10.8 g) of acid solution per 1 g of carbon black in a 5 mol / L hydrochloric acid solution and stirred at high speed at 60℃ for 1 hour. The mixture was repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 2 at a mass ratio of 10:1 and heat-treated.

[0128] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 2 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0129] Example 11

[0130] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. The muffle furnace was heated from room temperature to 500℃ at a rate of 10℃ / min under a nitrogen atmosphere and held at that temperature for 30 minutes. Then it was cooled to room temperature. The pyrolysis carbon black treated at high temperature was added to a 5mol / L sulfuric acid solution at a ratio of 10mL (13g) of acid solution per 1g of carbon black. The solution was stirred at high speed at 60℃ for 1 hour. The carbon black was repeatedly washed with water until the pH was 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and heat-treated.

[0131] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 1 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0132] Example 12

[0133] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. The muffle furnace was heated from room temperature to 500℃ at a rate of 10℃ / min under a nitrogen atmosphere and held at that temperature for 30 min, and then cooled to room temperature. The high-temperature treated pyrolysis carbon black was mixed with 10 mL (13.5 g) of acid solution per 1 g of carbon black and stirred at high speed at 60℃ for 1 h. The mixture was repeatedly washed with water until the pH was 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and heat-treated.

[0134] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 1 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0135] Example 13

[0136] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. Under a nitrogen atmosphere, the muffle furnace was heated from room temperature at a rate of 10℃ / min to 500℃ and held at that temperature for 30 min, then cooled to room temperature. The high-temperature treated pyrolysis carbon black was mixed with 10 mL (10.8 g) of acid solution per 1 g of carbon black in a 5 mol / L hydrochloric acid solution and stirred at high speed at 60℃ for 1 h. The mixture was repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 13:1 and then heat-treated.

[0137] The formulation and specific operation of the mixture of pickled pyrolysis carbon black and silane coupling agent 1 for heat treatment and the performance of modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0138] Comparative Example 1

[0139] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. The muffle furnace was heated from room temperature to 500℃ at a rate of 10℃ / min under a nitrogen atmosphere and held at that temperature for 30 minutes. Then it was cooled to room temperature. The pyrolysis carbon black treated at high temperature was added to a 5mol / L hydrochloric acid solution at a ratio of 10mL (10.8g) of acid solution per 1g of carbon black. The solution was stirred at high speed at 60℃ for 1 hour. The carbon black was repeatedly washed with water until the pH reached 6. The carbon black was then dried to obtain the acid-washed pyrolysis carbon black.

[0140] The pickled pyrolysis carbon black was added to the rubber according to the formulation in Table 3. The specific operation was as follows: 1) Rubber, carbon black, zinc oxide, and stearic acid were added sequentially to a mixer and mixed evenly at 55°C before being discharged. 2) The rubber compound was placed in a two-roll mill, and accelerator and sulfur were added. After mixing evenly, the compound was sheeted out to obtain the mixed rubber. 3) The mixed rubber was vulcanized at 145°C to obtain the vulcanized rubber. The performance test results of the vulcanized rubber of Comparative Example 1 are shown in Table 5.

[0141] Comparative Example 2

[0142] Unmodified pyrolysis carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and then heat-treated.

[0143] The heat treatment process of mixing unmodified pyrolysis carbon black with silane coupling agent 1 and the performance of modified pyrolysis carbon black in rubber, the formulation and specific operation are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0144] Comparative Example 3

[0145] After weighing the carbon black from the pyrolysis of waste tires, the furnace was placed in a muffle furnace. The furnace was heated from room temperature to 500°C at a rate of 10°C / min in a nitrogen atmosphere and held at that temperature for 30 minutes. Then it was cooled to room temperature.

[0146] The high-temperature treated pyrolysis carbon black was added to the rubber according to the formulation in Table 3 and the specific operation of Comparative Example 1. The properties of the resulting rubber are shown in Table 5.

[0147] Comparative Example 4

[0148] After weighing the pyrolysis carbon black from waste tires, it was placed in a muffle furnace. The muffle furnace was heated from room temperature at a rate of 10℃ / min in a nitrogen atmosphere until it reached 500℃, which was then held for 30 minutes. After that, it was cooled to room temperature. The pyrolysis carbon black treated at high temperature was mixed with silane coupling agent 1 at a mass ratio of 10:1 and then heat-treated.

[0149] The high-temperature treated pyrolysis carbon black was added to the rubber according to the formulation in Table 3 and the specific operation in Example 1. The properties of the resulting rubber are shown in Table 5.

[0150] Comparative Example 5

[0151] The thermal pyrolysis carbon black was mixed with 10 mL (10.8 g) of acid solution per 1 g of carbon black in 5 mol / L hydrochloric acid solution. The mixture was stirred at high speed for 1 h at 60 °C. The mixture was washed repeatedly with water until the pH was 6. The carbon black was dried to obtain acid-washed thermal pyrolysis carbon black. The ash content after acid washing is shown in Table 4.

[0152] The acid-washed pyrolysis carbon black was added to the rubber according to the formulation in Table 3 and the specific operation of Comparative Example 1. The properties of the resulting rubber are shown in Table 5.

[0153] Comparative Example 6

[0154] Pyrolytic carbon black was mixed with 10 mL (10.8 g) of acid solution per 1 g of carbon black in 5 mol / L hydrochloric acid solution and stirred at high speed at 60 °C for 1 h. The mixture was then repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolytic carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolytic carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and then heat-treated.

[0155] The acid-washed pyrolysis carbon black was added to the rubber according to the formulation in Table 3 and the specific operation in Example 1. The properties of the resulting rubber are shown in Table 5.

[0156] Comparative Example 7

[0157] The experiment is conducted by reversing the order of steps (1) and (2), as follows:

[0158] The pyrolysis carbon black was mixed with 10 mL (10.8 g) of acid solution per 1 g of carbon black in a 5 mol / L hydrochloric acid solution. The mixture was stirred at high speed at 60 °C for 1 h. The carbon black was repeatedly washed with water until the pH reached 6. The carbon black was then dried to obtain the acid-washed pyrolysis carbon black. The acid-washed pyrolysis carbon black was placed in a muffle furnace and heated from room temperature to 500 °C at a rate of 10 °C / min in a nitrogen atmosphere. The temperature was then held for 30 min and cooled to room temperature. The ash content after modification treatment is shown in Table 4.

[0159] The modified pyrolysis carbon black was added to the rubber according to the formulation in Table 3 and the specific operation of Comparative Example 1. The properties of the resulting rubber are shown in Table 5.

[0160] Comparative Example 8

[0161] The experiment is conducted by reversing the order of steps (1) and (2), as follows:

[0162] Pyrolytic carbon black was mixed with 10 mL (10.8 g) of acid solution per 1 g of carbon black in 5 mol / L hydrochloric acid solution and stirred at high speed at 60 °C for 1 h. The mixture was then repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolytic carbon black. The acid-washed pyrolytic carbon black was placed in a muffle furnace and heated from room temperature to 500 °C at a rate of 10 °C / min under a nitrogen atmosphere. The temperature was then held for 30 min and cooled to room temperature. The ash content after modification treatment is shown in Table 4. The treated pyrolytic carbon black was mixed with silane coupling agent 1 at a mass ratio of 10:1 and heat-treated.

[0163] The heat treatment process of mixing modified pyrolysis carbon black with silane coupling agent 1 and the performance of modified pyrolysis carbon black in rubber, the formulation and specific operation are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0164] Comparative Example 9

[0165] The waste tire pyrolysis carbon black was weighed and placed in a muffle furnace. The muffle furnace was heated from room temperature to 500℃ at a rate of 10℃ / min under a nitrogen atmosphere and held at that temperature for 30 minutes, and then cooled to room temperature. The high-temperature treated pyrolysis carbon black was mixed with 10 mL (10.8 g) of acid solution per 1 g of carbon black in a 5 mol / L hydrochloric acid solution and stirred at high speed at 60℃ for 1 hour. The mixture was repeatedly washed with water until the pH reached 6. The carbon black was dried to obtain acid-washed pyrolysis carbon black. The ash content after acid washing is shown in Table 4. The acid-washed pyrolysis carbon black was mixed with Si69 at a mass ratio of 10:1.

[0166] The heat treatment process of mixing modified pyrolysis carbon black with silane coupling agent Si69 and the formulation and specific operation of the modified pyrolysis carbon black in rubber are the same as in Example 1; the test results of vulcanized rubber performance are shown in Table 5.

[0167] Comparative Example 10

[0168] The ash content of the unmodified pyrolysis carbon black was measured and is shown in Table 4. The unmodified pyrolysis carbon black was added to the rubber according to the formulation in Table 3 and the specific operation of Comparative Example 1. The properties of the resulting rubber are shown in Table 5.

[0169] Comparative Example 11

[0170] Carbon black N330 was added to the rubber according to the formulation in Table 3 and the specific operation of Comparative Example 1. The properties of the resulting rubber are shown in Table 5.

[0171] Comparative Example 12

[0172] Carbon black N660 was added to the rubber according to the formulation in Table 3 and the specific operation of Comparative Example 1. The properties of the resulting rubber are shown in Table 5.

[0173] Table 4 Carbon Black Ash Content

[0174]

[0175]

[0176] Table 5 Rubber Properties

[0177]

[0178]

[0179] Comparative Examples 3 and 4 show that while high-temperature treatment alone, or the addition of a coupling agent after high-temperature treatment, improves the tensile strength of the rubber composite material, it also significantly reduces the tensile strength. Comparative Examples 5 and 6 show that directly modifying pyrolytic carbon black by acid washing or adding a coupling agent after acid washing results in a smaller reduction in ash content, lower acid washing efficiency, and less improvement in the mechanical properties of the rubber composite material. Examples 1, 2, and 3, under different high-temperature treatment conditions and the same acid washing conditions, show significant differences in ash reduction effects, indicating that sufficient high-temperature treatment can improve acid washing efficiency. Results: Table 4 shows that sufficient acid solution treatment after high-temperature treatment can effectively reduce the ash content of pyrolysis carbon black. In Comparative Examples 7 and 8, reversing the order of acid washing and high temperature treatment resulted in less ash reduction and lower acid washing efficiency, demonstrating the importance of the experimental order in this invention. Table 5 shows that the treatment method for pyrolysis carbon black from waste tires provided by this invention can effectively improve the tensile strength and hardness of pyrolysis carbon black-rubber composites while maintaining high tensile strength, reaching a higher level than the reference sample (meaning exceeding N660 level and approaching N330 level), thus improving the reinforcing performance of pyrolysis carbon black in rubber materials. Although the high-temperature heat treatment and acid treatment steps in Comparative Example 9 are the same as in this application, the silane coupling agent used in the final mixed heat treatment is not the silane coupling agent of this invention, resulting in a decrease in the mechanical properties of the carbon black-rubber composite material.

[0180] Depend on Figure 1 and Figure 2 It can be seen that, compared to commercial carbon black, pyrolysis carbon black has a larger and more uneven surface morphology, with blurred particle edges, inconsistent shapes, and particles that adhere to each other. Figure 3 It can be seen that after high-temperature heat treatment, the edges of the pyrolysis carbon black particles become clearer, exhibiting a spherical shape. Figure 4 and Figure 5 It can be seen that high-temperature heat treatment under a nitrogen atmosphere before pickling can effectively improve the pickling effect. The microstructure of the pyrolysis carbon black after pickling is closer to that of commercial carbon black, the impurity coverage is significantly reduced, the pores between aggregates are more numerous, and the characteristics of nanoparticles are more obvious.

Claims

1. A method for modifying waste tire pyrolysis carbon black, characterized by The method comprises: (1) high-temperature treatment of the pyrolysis carbon black; (2) adding the high-temperature treated pyrolysis carbon black in (1) into an acid solution, stirring to obtain an aqueous suspension of the pickled pyrolysis carbon black, and drying after water washing to obtain the pickled pyrolysis carbon black; (3) mixing and heat-treating the pickled pyrolysis carbon black obtained in (2) with a silane coupling agent to obtain the modified pyrolysis carbon black; In step (1), the high-temperature treatment is performed under a nitrogen atmosphere or vacuum conditions; the high-temperature treatment temperature is 300-600℃; In step (2), the acid solution is one of nitric acid solution, hydrochloric acid solution, and sulfuric acid solution; the concentration of the acid solution is 2-7 mol / L; In step (3), the silane coupling agent is a silane polymer containing a polyether chain segment, and has the following general formula: RxSiyOz(OR1)wO(R2)mQn... Formula (I) In Formula (I), x is 2-12; y is 2-12; z is 2-12; w is 2-24; m is 1-6; n is 1-24; R is a straight-chain or branched-chain or cycloalkyl or aromatic hydrocarbon alkyl or alkenyl group with C3-C36; R1 is methyl or ethyl; R2 is a fatty chain containing a polyether structure, and has the structural formula R3-(C2H4O)k-, wherein R3 is a saturated fatty chain with C3-C18, and k is an integer of 3-9; Q is S or SH.

2. The modification method according to claim 1, wherein: In step (1), the high-temperature treatment temperature is 400-500℃, and the high-temperature treatment time is 15 min-1 h.

3. The modification method of claim 2, wherein: the high-temperature treatment time is 30 min-40 min.

4. The modification method according to claim 3, wherein: In step (2), the mass ratio of the high-temperature treated pyrolysis carbon black to the acid solution is 1:5-1:

20.

5. The modification method according to claim 1, wherein: In step (2), the stirring temperature is 50℃-80℃, and the stirring time is 30 min-2 h; the water washing is performed until the pH is 5-6, and then drying is performed.

6. The modification method according to claim 1, wherein: In Formula (I), x is 2-6; y is 2-6; z is 2-6; w is 2-12; n is 1-12; R is a straight-chain or branched-chain alkyl group with C3-C18.

7. The modification method according to claim 6, wherein: In step (3), the preparation method of the silane polymer containing a polyether chain segment comprises heating and reacting components containing a silane compound and a fatty alcohol polyoxyethylene ether to obtain the silane polymer containing a polyether chain segment.

8. The modification method according to claim 1, wherein: In step (3), the mass ratio of the pickled pyrolysis carbon black to the silane coupling agent is 8:1-15:1; the mixing and heat-treatment of the pickled pyrolysis carbon black and the silane coupling agent is mixing the pickled pyrolysis carbon black and the silane coupling agent, and then heat-treating at 140℃-160℃ for 4-6 min; 9. The modification method of claim 8, wherein: the mass ratio of the pickled pyrolysis carbon black to the silane coupling agent is 10:1-13:

1.

10. Carbon black produced according to the process of any one of claims 1 to 9.

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