Preparation method of modified pyrolysis carbon black and method for reinforcing natural rubber by using modified pyrolysis carbon black
By pretreating and grafting modification of cracked carbon black, a double reinforcement structure was constructed, which solved the problem of insufficient reinforcement effect of cracked carbon black in rubber matrix, and achieved performance improvements comparable to commercial carbon black and applied to rubber material reinforcement.
Patent Information
- Application Number
- CN202510556963.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-29
- Publication Date
- 2025-07-25
AI Technical Summary
There is still a gap in the reinforcement effect of cracked carbon black in rubber matrix and commercial carbon black. The improvement of existing modification methods is limited, and there are problems of environmental pollution and equipment investment.
The silicon content is controlled through pretreatment, and the synergistic effect of graft modification and silica in the ash is used to build a dual reinforcement structure on the surface of the carbon black, including pickling, oxidation, acid chloride and cystamine coupling agent modification, to enhance the surface activity and hydrophilicity of the carbon black, increase the active site, and achieve close bonding with natural rubber.
Significantly improve the mechanical properties of cracked carbon black, so that its reinforcement performance in rubber materials reaches or is close to the level of commercial carbon black, and can partially or completely replace commercial carbon black and be used in tires and other rubber products.
Smart Images
Figure BDA0005383648680000151
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of resource recycling and utilization, and particularly to a preparation method of modified pyrolytic carbon black and a method for reinforcing natural rubber by using the same. Background Art
[0002] With the rapid development of the automotive industry, the quantity of waste tires has increased sharply, and their treatment has become a severe environmental and resource problem. Pyrolysis of waste tires is an effective way of recycling and utilization, and products such as pyrolytic carbon black can be obtained. In the rubber industry, as an important product of waste tire resource utilization, improving the performance of pyrolytic carbon black is crucial for realizing the recycling and utilization of carbon black. However, due to the defects of its own structure and performance, such as low surface activity and poor dispersibility, when pyrolytic carbon black partially replaces commercial carbon black as a rubber reinforcing agent, its reinforcing effect cannot be fully exerted. Specifically, the key mechanical properties such as tensile strength, tear strength and abrasion resistance of rubber products are much lower than those of traditional carbon black, which limits its wide application in the rubber industry.
[0003] In view of the common problems in the application of pyrolytic carbon black, although there are various existing modification methods to attempt to improve its reinforcing performance, such as reducing ash content, preparing ultrafine particle size, oxidation method, plasma modification and surface coating, etc., they all face disadvantages such as serious environmental pollution, large equipment investment, large amount of waste liquid and inconvenient operation, and the improvement amplitude of rubber reinforcing effect is limited. In addition, grafting modification is an effective means to endow carbon black with special functions. By grafting short-chain polymers with different structures onto the surface of carbon black in a targeted manner, the application performance of carbon black can be improved.
[0004] However, at present, there is still a gap between the reinforcing effect of pyrolytic carbon black treated by the above methods in the rubber matrix and commercial carbon black. There is an urgent need to develop a reinforcing agent and a grafting method that can effectively improve its performance. Summary of the Invention
[0005] The purpose of the present invention is to provide a preparation method of modified pyrolytic carbon black and a method for reinforcing natural rubber by using the same. By controlling the silicon content through pretreatment and utilizing the synergistic effect of grafting modification and silica in ash, a dual reinforcing structure is constructed on the surface of carbon black, thereby significantly improving the reinforcing performance of pyrolytic carbon black in rubber materials, reaching or approaching the level of commercial carbon black, and providing an efficient and feasible technical path for the high-value utilization of waste tire pyrolytic carbon black.
[0006] To achieve the above purpose, the present invention adopts the following specific technical solutions:
[0007] In the first aspect, the present invention provides a preparation method of modified pyrolytic carbon black, and the preparation method includes the following steps:
[0008] S1: Pretreat the pyrolytic carbon black in a liquid dispersion system comprising an acid cleaning agent, an oxidizing agent, and a surfactant, and then wash, filter, and dry to obtain silicon-containing activated carbon black.
[0009] Optionally, the acid cleaning agent includes inorganic acid and / or organic acid, which can be one or more of nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, perchloric acid, formic acid, acetic acid, oxalic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, or sulfamic acid, and a mixture with hydrofluoric acid; the concentration of the acid cleaning agent in the liquid dispersion system is 1-5M.
[0010] Optionally, the oxidizing agent includes one or more of hydrogen peroxide, potassium permanganate, ammonium persulfate, or potassium dichromate, and the concentration of the oxidizing agent in the liquid dispersion system is 2-8M.
[0011] Optionally, the surfactant includes one or more of sodium dodecylsulfonate (SDS), sodium dodecylbenzenesulfonate (SDBS), cetyltrimethylammonium bromide (CTAB), or sodium stearate, and the concentration of the surfactant in the liquid dispersion system is 0.1-2g·L -1 。
[0012] Furthermore, the mass fraction of hydrofluoric acid in the acid cleaning agent in the liquid dispersion system is 1.5-6wt%, which can effectively control the silica content of the silicon-containing activated carbon black. The more the amount of hydrofluoric acid used, the lower the silica content.
[0013] Preferably, the silica content of the silicon-containing activated carbon black is 4-10%, and controlling the silica content in the ash and its synergistic effect with the modified pyrolytic carbon black in the subsequent process is one of the keys of the present invention.
[0014] Preferably, the particle size of the silicon-containing activated carbon black is 20-100nm, and the content of oxygen-containing functional groups in the ash of the silicon-containing activated carbon black is 0.5-2mmol·g -1 。
[0015] Furthermore, the temperature of the pretreatment is 50-90°C, the time of the pretreatment is 2-8h, stirring is carried out at 100-600rpm during the pretreatment, and the pretreatment is carried out under light-shielded conditions.
[0016] Furthermore, the solid-liquid ratio of the pyrolytic carbon black and the liquid dispersion system is 1g:5-20mL.
[0017] Furthermore, the drying can be carried out at 80-120°C.
[0018] S2: Take a portion of the silicon-containing activated carbon black and disperse it in a solvent. Add an acyl chlorination reagent and a first catalyst and react. After the reaction is completed, distill under reduced pressure to obtain acyl chlorinated carbon black.
[0019] Optionally, the acyl chlorination reagent includes one or more of thionyl chloride, oxalyl chloride, or phosphorus trichloride.
[0020] Optionally, the first catalyst includes triethylamine and / or 4-dimethylaminopyridine.
[0021] Optionally, the solvent is one or more of toluene, xylene, chlorobenzene, dichloromethane, DMF, ethanol, or tetrahydrofuran.
[0022] Further, the dosage ratio of the silicon-containing activated carbon black, acyl chlorination reagent, first catalyst, and solvent is 50 - 100 g: 12.5 - 25 g: 0.5 - 1.0 mL: 250 - 500 mL.
[0023] Further, the temperature of the reaction is 0 - 160 °C. Preferably, the reaction is first carried out at 0 - 10 °C for 0.5 - 2 h, and then gradually heated to 100 - 160 °C and reacted for 30 - 60 min.
[0024] S3: Add a cysteamine coupling agent to modify the surface of the acyl chlorinated carbon black. After the reaction is completed, distill under reduced pressure to obtain the modified pyrolytic carbon black.
[0025] Optionally, the cysteamine coupling agent includes cysteamine dihydrochloride, etc.
[0026] Further, the mass ratio of the acyl chlorinated carbon black to the cysteamine coupling agent is 10 - 70: 1.48 - 10.36.
[0027] Further, the temperature of the surface modification is 0 - 120 °C. Preferably, the surface modification is first carried out at 0 - 10 °C for 0.5 - 2 h, and then gradually heated to 80 - 120 °C and reacted for 4 - 24 h; the surface modification is carried out in an inert gas atmosphere.
[0028] Further, in step S3, an alkali, a solvent, and a second catalyst are also added; the dosage ratio of the acyl chlorinated carbon black, cysteamine coupling agent, alkali, and solvent is 10 - 70 g: 1.48 - 10.36 g: 0.77 - 5.37 g: 50 - 365 mL.
[0029] Further, the mass of the second catalyst is 5 - 15% of the mass of the acyl chlorinated carbon black.
[0030] In a second aspect, the present invention also provides a method for reinforcing natural rubber based on the preparation method of the modified pyrolytic carbon black: after the natural rubber is kneaded in a mixer, the cysteamine grafted carbon black, antioxidant, zinc oxide, stearic acid, etc. are added for mixing; then sulfur, accelerator, etc. are added for open milling to obtain the product.
[0031] Further, the natural rubber, cysteamine grafted carbon black, antioxidant, zinc oxide, stearic acid, sulfur, and accelerator are respectively 150 parts, 10 - 70 parts, 3 - 6 parts, 3 - 7.5 parts, 4.5 - 9 parts, 2.55 - 5.1 parts, and 2.55 - 5.1 parts by mass.
[0032] Preferably, 5 - 65 parts of the silicon - containing activated carbon black is added simultaneously or after adding the cysteamine grafted carbon black.
[0033] Optionally, the accelerator includes one or more of dibenzothiazole disulfide (DM), 2 - mercaptobenzothiazole (MBT), N - cyclohexyl - 2 - benzothiazole sulfenamide (CZ), or diphenylguanidine (DPG).
[0034] Optionally, the antioxidant includes one or more of N - isopropyl - N'- phenyl - p - phenylenediamine (4020), N - phenyl - α - naphthylamine (PAN), or 2,6 - di - tert - butyl - 4 - methylphenol (BHT).
[0035] Compared with the prior art, the present invention has the following beneficial effects:
[0036] By subjecting the pyrolytic carbon black to surface treatments such as purification, oxidation, and acyl chlorination, the present invention removes surface impurities, activates the surface, and regulates the surface properties of the carbon black. By adjusting the surface energy and wettability, the hydrophilicity and dispersibility of the carbon black are improved, and by increasing the active groups to introduce more active sites, the reaction activity is enhanced, which is beneficial for introducing cysteamine graft that can be used as a reinforcing agent onto the carbon black surface through free - radical polymerization.
[0037] Since cysteamine contains two amino groups and sulfur bonds, it can make the hydroxyl groups attached to the surface of silica, and the acyl chloride groups, carboxyl groups, and hydroxyl groups attached to the surface of carbon black bond more tightly with natural rubber, greatly improving the cross - link density and the filler network structure such as bound rubber, thus efficiently improving the mechanical properties of the pyrolytic carbon black and having high application potential.
[0038] The modified pyrolytic carbon black of the present invention has good utility in reinforcement. It can meet the reinforcement agent standards in terms of 300% modulus at elongation, tensile strength, etc. The grafted carbon black for reinforcement can partially or completely replace commercial carbon black or commercial silane coupling agents in the preparation of rubber compositions, and can also be applied in the production process of tires and other non - tire rubber products. Specific embodiments
[0039] The embodiments of the present invention will be described in detail below in conjunction with specific embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. For those not specified in the embodiments, they are carried out under conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase. The pyrolytic carbon black was purchased from Hubei Zhongshuo Environmental Protection Co., Ltd., nitric acid, hydrogen peroxide, and hydrofluoric acid were purchased from Beijing Tongguang Fine Chemical Co., Ltd., SDS, cystamine dihydrochloride, thionyl chloride, and tetrahydrofuran were purchased from Shanghai Macklin Biochemical Co., Ltd., potassium hydroxide, triethylamine, dichloromethane, potassium carbonate, and potassium iodide were purchased from Aladdin Reagent (Shanghai) Co., Ltd., natural rubber was purchased from Hainan Natural Rubber Industry Group Co., Ltd., carbon black (grade N660) was purchased from Jiangxi Black Cat Carbon Black Co., Ltd., zinc oxide was purchased from Beijing Hengtianyi Chemical Co., Ltd., stearic acid was purchased from Beijing Hengtianyi Chemical Co., Ltd., accelerator DM and antioxidant 4020 were purchased from Kemai Chemical Co., Ltd., and sulfur (industrial grade) was purchased from Beijing Hengtianyi Chemical Co., Ltd.
[0040] If there are no special limitations on the addition amounts of various substances in the present invention, any ratio can be adopted.
[0041] Example 1
[0042] A preparation method of modified pyrolytic carbon black:
[0043] (1) The pyrolytic carbon black was placed in a liquid-phase dispersion system composed of 2M nitric acid, 3wt% hydrofluoric acid, 2M hydrogen peroxide, and 1 g·L -1 sodium dodecyl sulfate (SDS) for pretreatment. Among them, nitric acid: hydrofluoric acid: hydrogen peroxide: SDS = 1 mol: 0.75 mol: 1 mol: 1.73 mmol, the solid-liquid ratio was 1 g: 10 mL, and the reaction was carried out at a constant temperature of 80 °C in the dark for 4 h at a rotation speed of 400 rpm. After the pretreatment, it was washed, filtered, and dried to obtain silicon-containing activated carbon black (the silicon dioxide content was 8%);
[0044] (2) 50 g of the obtained silicon-containing activated carbon black was dispersed in 250 mL of toluene, then 12.5 g of thionyl chloride and 0.5 mL of triethylamine were added. The reaction was first carried out at 0 °C for 0.5 h, and then gradually heated to 120 °C for 30 min. After the reaction, it was distilled under reduced pressure at 80 °C to obtain acyl chloride carbon black;
[0045] (3) Disperse 10 g of the obtained carbon black acyl chloride in 50 mL of toluene, then add 1.48 g of cystamine dihydrochloride and 0.77 g of sodium carbonate, add 2.5 mL of tetrahydrofuran to assist dissolution, and the dosage of potassium carbonate - potassium iodide is 0.5 g. React at 0 °C for 0.5 h in a nitrogen atmosphere first, then gradually raise the temperature to 80 °C and react for 12 h. After the reaction, perform vacuum distillation at 80 °C to obtain cystamine-grafted carbon black.
[0046] Method for reinforcing natural rubber based on the preparation method of the modified pyrolytic carbon black:
[0047] Prepare 150 parts of natural rubber, 10 parts of cystamine-grafted carbon black, 65 parts of silica-activated carbon black, 2.55 parts of environmentally friendly sulfur, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020), and 7.5 parts of zinc oxide according to mass parts.
[0048] Set the rotor of the internal mixer to 70 rpm and the initial temperature to 80 °C. Put the natural rubber into the internal mixer chamber for mixing. Pull out the bolt after 30 s of tearing and shearing; add the cystamine-grafted carbon black and silica-activated carbon black into the chamber in two batches successively, and mix until the torque curve tends to be stable, about 3 min; add the antioxidant, then add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min; after the mixed rubber is cooled to room temperature, open mill it on an open mill, adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet, and when the rubber compound becomes uniformly black, pass the rubber compound through the roll gap without wrapping the roll six times, make three triangular wraps and three rolls, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll gap three times, adjust the roll gap to 2.2 mm and take off the sheet to obtain the product.
[0049] Example 2
[0050] A preparation method of modified pyrolytic carbon black:
[0051] (1) Place the pyrolytic carbon black in a liquid-phase dispersion system composed of 2 M nitric acid, 6 wt% hydrofluoric acid, 2 M hydrogen peroxide, and 1 g·L -1 Cetyltrimethylammonium bromide (CTAB) for pretreatment, where nitric acid: hydrofluoric acid: hydrogen peroxide: SDS = 1 mol: 1.5 mol: 1 mol: 1.73 mmol, the solid-liquid ratio is 1 g: 10 mL, react at 80 °C under constant temperature and in the dark for 4 h, the rotation speed is 400 rpm. After pretreatment, wash, filter, and dry to obtain silica-activated carbon black (the silica content is 4%);
[0052] (2) Disperse 50 g of the obtained silica-activated carbon black in 300 mL of toluene, then add 15 g of thionyl chloride and 1.0 mL of triethylamine, react at 0 °C for 0.5 h first, then gradually raise the temperature to 120 °C and react for 30 min. After the reaction, perform vacuum distillation at 80 °C to obtain carbon black acyl chloride;
[0053] (3) Disperse 30 g of the obtained carbon black acyl chloride in 150 mL of toluene, then add 4.44 g of cystamine dihydrochloride and 2.30 g of sodium carbonate, add 7.5 mL of tetrahydrofuran to assist dissolution, the dosage of potassium carbonate - potassium iodide is 2 g. First, react at 0 °C for 0.5 h in a nitrogen atmosphere, then gradually heat up to 80 °C and react for 12 h. After the reaction, perform vacuum distillation at 80 °C to obtain cystamine-grafted carbon black.
[0054] Method for reinforcing natural rubber based on the preparation method of the modified pyrolytic carbon black:
[0055] Prepare 150 parts of natural rubber, 30 parts of cystamine-grafted carbon black, 45 parts of silicon-containing activated carbon black, 2.55 parts of environmentally friendly sulfur, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020), and 7.5 parts of zinc oxide according to mass parts.
[0056] Set the rotor of the internal mixer to 70 rpm and the initial temperature to 80 °C. Put the natural rubber into the internal mixer chamber for mixing. After 30 s of tearing and shearing, lift the bolt; add the cystamine-grafted carbon black and the silicon-containing activated carbon black into the chamber in two batches successively, and mix until the torque curve tends to be stable, about 3 min; add the antioxidant, then add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min; after the mixed rubber is cooled to room temperature, open mill it on an open mill, adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet. After the rubber compound becomes uniformly black, pass the rubber compound through the rolls without wrapping the rolls six times, make three triangular wraps and three rolls, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll gap three times, and adjust the roll gap to 2.2 mm to take off the sheet, thus obtaining.
[0057] Example 3
[0058] A preparation method of modified pyrolytic carbon black:
[0059] (1) Place the pyrolytic carbon black in a liquid-phase dispersion system composed of 2 M nitric acid, 1.5 wt% hydrofluoric acid, 2 M hydrogen peroxide, and 1 g·L -1 sodium dodecyl sulfate (SDS) for pretreatment, where nitric acid:hydrofluoric acid:hydrogen peroxide:SDS = 1 mol:0.375 mol:1 mol:1.73 mmol, the solid-liquid ratio is 1 g:10 mL, react at 80 °C under constant temperature and in the dark for 4 h, the rotation speed is 400 rpm. After the pretreatment, wash, filter, and dry to obtain silicon-containing activated carbon black (the silicon dioxide content is 10%);
[0060] (2) Disperse 50 g of the obtained silicon-containing activated carbon black in 350 mL of toluene, then add 20 g of thionyl chloride and 0.8 mL of triethylamine. First, react at 0 °C for 0.5 h, then gradually raise the temperature to 120 °C and react for 30 min. After the reaction is completed, carry out reduced-pressure distillation at 80 °C to obtain acyl chloride carbon black;
[0061] (3) Disperse 50 g of the obtained acyl chloride carbon black in 320 mL of toluene, then add 7.40 g of cystamine dihydrochloride and 3.84 g of sodium carbonate. Add 12.5 mL of tetrahydrofuran to assist dissolution. The dosage of potassium carbonate-potassium iodide is 5 g of the dosage of acyl chloride carbon black. First, react at 0 °C for 0.5 h in a nitrogen atmosphere, then gradually raise the temperature to 80 °C and react for 12 h. After the reaction is completed, carry out reduced-pressure distillation at 80 °C to obtain cystamine-grafted carbon black.
[0062] Method for reinforcing natural rubber based on the preparation method of the modified pyrolytic carbon black:
[0063] Prepare 150 parts of natural rubber, 50 parts of cystamine-grafted carbon black, 25 parts of silicon-containing activated carbon black, 2.55 parts of environmental protection sulfur, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020), and 7.5 parts of zinc oxide according to mass parts.
[0064] Set the rotor of the internal mixer to 70 rpm and the initial temperature to 80 °C. Put the natural rubber into the chamber of the internal mixer, and pull out the bolt after 30 s of tearing and shearing; add the cystamine-grafted carbon black and the silicon-containing activated carbon black into the chamber successively in two times, and mix until the torque curve tends to be stable, about 3 min; add the antioxidant, then add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min; after the mixed rubber is cooled to room temperature, carry out open mixing on the two-roll mill, adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet, until the rubber compound becomes uniformly black, then pass the rubber compound through the rolls without wrapping the rolls thinly six times, make three triangular packages and three rolls, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll gap three times, adjust the roll gap to 2.2 mm and take off the sheet to obtain.
[0065] Example 4
[0066] A preparation method of modified pyrolytic carbon black:
[0067] Disperse 70 g of the acyl chloride carbon black prepared according to the method of Example 1 in 350 mL of toluene, then add 10.36 g of cystamine dihydrochloride and 5.37 g of sodium carbonate. Add 17.5 mL of tetrahydrofuran to assist dissolution. The dosage of potassium carbonate-potassium iodide is 3.5 g. First, react at 0 °C for 0.5 h in a nitrogen atmosphere, then gradually raise the temperature to 80 °C and react for 12 h. After the reaction is completed, carry out reduced-pressure distillation at 80 °C to obtain cystamine-grafted carbon black.
[0068] Method for reinforcing natural rubber based on the preparation method of the modified pyrolytic carbon black:
[0069] Prepare 150 parts of natural rubber, 70 parts of cysteamine grafted carbon black, 5 parts of silicon-containing activated carbon black, 5.1 parts of environmentally friendly sulfur, 5.1 parts of dibenzothiazole disulfide (DM), 9 parts of stearic acid, 6 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020), and 5 parts of zinc oxide by mass.
[0070] Set the rotor of the internal mixer to 70 rpm and the initial temperature to 80 °C. Put the natural rubber into the chamber of the internal mixer and perform tearing and shearing for 30 s, then lift the ram. Add the cysteamine grafted carbon black and the silicon-containing activated carbon black into the chamber in two batches successively and mix until the torque curve tends to be stable, about 3 min. Add the antioxidant, then add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min. After the mixed rubber is cooled to room temperature, perform open milling on the two-roll mill. Adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet. After the rubber compound becomes uniformly black, pass the non-bundle rubber sheet through the mill six times, make three triangular bales and three coils, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll gap three times, and adjust the roll gap to 2.2 mm to take off the sheet, thus obtaining the product.
[0071] Comparative Example 1
[0072] A method for reinforcing natural rubber:
[0073] Prepare 150 parts of natural rubber, 75 parts of silicon-containing activated carbon black prepared according to the method of Example 1, 2.55 parts of environmentally friendly sulfur, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020), and 7.5 parts of zinc oxide by mass.
[0074] Set the rotor of the internal mixer to 70 rpm and the initial temperature to 80 °C. Put the natural rubber into the chamber of the internal mixer and perform tearing and shearing for 30 s, then lift the ram. Add the silicon-containing activated carbon black into the chamber and mix until the torque curve tends to be stable, about 3 min. Add the antioxidant, then add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min. After the mixed rubber is cooled to room temperature, perform open milling on the two-roll mill. Adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet. After the rubber compound becomes uniformly black, pass the non-bundle rubber sheet through the mill six times, make three triangular bales and three coils, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll gap three times, and adjust the roll gap to 2.2 mm to take off the sheet, thus obtaining the product.
[0075] Comparative Example 2
[0076] A method for reinforcing natural rubber:
[0077] Prepare 150 parts by mass of natural rubber, 75 parts of pyrolytic carbon black, 2.55 parts of environment-friendly sulfur, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020), and 7.5 parts of zinc oxide.
[0078] Set the rotor of the internal mixer to 70 rpm and the initial temperature to 80 °C. Put the natural rubber into the chamber of the internal mixer, lift the ram after 30 s of tearing and shearing; add the pyrolytic carbon black into the chamber and mix until the torque curve tends to be stable, about 3 min; add the antioxidant, then add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min; after the mixed rubber is cooled to room temperature, open mill it on an open mill, adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet, and when the rubber compound becomes uniformly black, pass the non-packing roll thinly through six times, make three triangular bales and three rolls, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll nip three times, and adjust the roll gap to 2.2 mm to take off the sheet, thus obtaining.
[0079] Comparative Example 3
[0080] A method for reinforcing natural rubber:
[0081] Prepare 150 parts by mass of natural rubber, 75 parts of commercial N660, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020), and 7.5 parts of zinc oxide.
[0082] Set the rotor of the internal mixer to 70 rpm and the initial temperature to 80 °C. Put the natural rubber into the chamber of the internal mixer, lift the ram after 30 s of tearing and shearing; add the commercial N660 into the chamber and mix until the torque curve tends to be stable, about 3 min; add the antioxidant, then add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min; after the mixed rubber is cooled to room temperature, open mill it on an open mill, adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet, and when the rubber compound becomes uniformly black, pass the non-packing roll thinly through six times, make three triangular bales and three rolls, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll nip three times, and adjust the roll gap to 2.2 mm to take off the sheet, thus obtaining.
[0083] Comparative Example 4
[0084] A method for reinforcing natural rubber:
[0085] Prepare 150 parts by mass of natural rubber, 70 parts of pyrolytic carbon black, 5 parts of cystamine dihydrochloride, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020), and 7.5 parts of zinc oxide.
[0086] Set the rotor of the internal mixer to 70 rpm, set the initial temperature to 80 °C, put natural rubber into the chamber for internal mixing, pull out the plug after 30 s of tearing and shearing; add pyrolytic carbon black and cystamine dihydrochloride to the chamber, and mix until the torque curve tends to be stable, about 3 min; add antioxidant, add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min; after the mixed rubber is cooled to room temperature, open mill it on an open mill, adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet, until the rubber compound is uniformly black, pass the rubber compound through the rolls without wrapping six times, make three triangular bales and three rolls, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll gap three times, and adjust the roll gap to 2.2 mm to take off the sheet, thus obtaining.
[0087] Comparative Example 5
[0088] A method for reinforcing natural rubber:
[0089] Prepare 150 parts of natural rubber, 70 parts of pyrolytic carbon black, 5 parts of commercial Si69, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020) and 7.5 parts of zinc oxide according to mass parts.
[0090] Set the rotor of the internal mixer to 70 rpm, set the initial temperature to 80 °C, put natural rubber into the chamber for internal mixing, pull out the plug after 30 s of tearing and shearing; add pyrolytic carbon black and commercial Si69 to the chamber, and mix until the torque curve tends to be stable, about 3 min; add antioxidant, add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min; after the mixed rubber is cooled to room temperature, open mill it on an open mill, adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet, until the rubber compound is uniformly black, pass the rubber compound through the rolls without wrapping six times, make three triangular bales and three rolls, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll gap three times, and adjust the roll gap to 2.2 mm to take off the sheet, thus obtaining.
[0091] Comparative Example 6
[0092] A method for reinforcing natural rubber:
[0093] Prepare 150 parts of natural rubber, 70 parts of pyrolytic carbon black, 5 parts of commercial KH550, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020) and 7.5 parts of zinc oxide according to mass parts.
[0094] Preparation method of carbon black reinforced natural rubber, comprising the following steps: Set the rotor of the internal mixer to 70 rpm, set the initial experimental temperature to 80 °C, put natural rubber into the chamber of the internal mixer, lift the ram after 30 s of tearing and shearing; Add pyrolytic carbon black and commercial KH550 into the chamber, and mix until the torque curve tends to be stable, about 3 min; Add antioxidant, then add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min; After the mixed rubber is cooled to room temperature, open mill it on an open mill, adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet, until the rubber compound becomes uniformly black, then pass the rubber compound through the rolls without wrapping the rolls six times, make three triangular bales and three rolls, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll gap three times, adjust the roll gap to 2.2 mm and take off the sheet, thus obtaining the product.
[0095] Comparative Example 7
[0096] A preparation method of modified pyrolytic carbon black:
[0097] (1) Pretreat pyrolytic carbon black in a liquid-phase dispersion system composed of 2M nitric acid, 7.5 wt% hydrofluoric acid, 2M hydrogen peroxide and 1 g·L -1 sodium dodecyl sulfate (SDS), where nitric acid: hydrofluoric acid: hydrogen peroxide: SDS = 1 mol: 1.88 mol: 1 mol: 1.73 mmol, the solid-liquid ratio is 1 g: 10 mL, react at 80 °C under constant temperature and in the dark for 6 h, the rotation speed is 400 rpm, after the pretreatment is completed, wash, filter and dry to obtain silicon-containing activated carbon black (the silicon dioxide content is 2%);
[0098] (2) Disperse 50 g of the obtained silicon-containing activated carbon black in 250 mL of toluene, then add 12.5 g of thionyl chloride and 0.5 mL of triethylamine, react at 0 °C for 0.5 h first, then gradually heat up to 120 °C and react for 30 min, after the reaction is completed, distill under reduced pressure at 80 °C to obtain acyl chloride carbon black;
[0099] (3) Disperse 10 g of the obtained acyl chloride carbon black in 50 mL of toluene, then add 1.48 g of cystamine dihydrochloride and 0.77 g of sodium carbonate, add 2.5 mL of tetrahydrofuran to assist dissolution, the dosage of potassium carbonate-potassium iodide is 0.5 g, react at 0 °C for 0.5 h first in a nitrogen atmosphere, then gradually heat up to 80 °C and react for 12 h, after the reaction is completed, distill under reduced pressure at 80 °C to obtain cystamine-grafted carbon black.
[0100] Method for reinforcing natural rubber based on the preparation method of the modified pyrolytic carbon black:
[0101] Prepare 150 parts by mass of natural rubber, 10 parts of cysteamine-grafted carbon black, 65 parts of silica-activated carbon black (silica content is 2%), 2.55 parts of environmentally friendly sulfur, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020), and 7.5 parts of zinc oxide.
[0102] Set the rotor of the internal mixer to 70 rpm and the initial temperature to 80 °C. Put the natural rubber into the chamber of the internal mixer, lift the ram after 30 s of tearing and shearing; add the cysteamine-grafted carbon black and silica-activated carbon black into the chamber in two batches successively, and mix until the torque curve tends to be stable, about 3 min; add the antioxidant, add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min; after the mixed rubber is cooled to room temperature, open mill it on the open mill, adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet, and when the rubber compound becomes uniformly black, pass the rubber compound through the rolls without sticking to the rolls for six times, make three triangular bales and three rolls, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll gap three times, adjust the roll gap to 2.2 mm and take off the sheet, then it is obtained.
[0103] Comparative Example 8
[0104] A preparation method of modified pyrolytic carbon black:
[0105] (1) Place the pyrolytic carbon black in a liquid-phase dispersion system composed of 2 M nitric acid, 2 M hydrogen peroxide and 1 g·L -1 sodium dodecyl sulfonate (SDS) for pretreatment. The solid-liquid ratio is 1 g:10 mL, react at a constant temperature of 80 °C in the dark for 4 h, rotate at 400 rpm. After the pretreatment, wash, filter and dry to obtain silica-activated carbon black (silica content is 12%);
[0106] (2) Disperse 50 g of the obtained silica-activated carbon black in 250 mL of toluene, then add 12.5 g of thionyl chloride and 0.5 mL of triethylamine. React at 0 °C for 0.5 h first, then gradually heat up to 120 °C and react for 30 min. After the reaction is completed, distill under reduced pressure at 80 °C to obtain acyl chloride carbon black;
[0107] (3) Disperse 10 g of the obtained acyl chloride carbon black in 50 mL of toluene, then add 1.48 g of cysteamine dihydrochloride and 0.77 g of sodium carbonate, add 2.5 mL of tetrahydrofuran to assist dissolution, the dosage of potassium carbonate-potassium iodide is 0.5 g. React at 0 °C for 0.5 h first in a nitrogen atmosphere, then gradually heat up to 80 °C and react for 12 h. After the reaction is completed, distill under reduced pressure at 80 °C to obtain cysteamine-grafted carbon black.
[0108] A method for reinforcing natural rubber based on the preparation method of the modified pyrolytic carbon black:
[0109] Prepare 150 parts by mass of natural rubber, 10 parts of cysteamine-grafted carbon black, 65 parts of silica-activated carbon black (silica content is 12%), 2.55 parts of environment-friendly sulfur, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020), and 7.5 parts of zinc oxide.
[0110] Set the rotor of the internal mixer to 70 rpm and the initial temperature to 80 °C. Put the natural rubber into the chamber of the internal mixer and lift the ram after 30 s of tearing and shearing. Add the cysteamine-grafted carbon black and silica-activated carbon black into the chamber in two batches successively and mix until the torque curve tends to be stable, about 3 min. Add the antioxidant, then add zinc oxide and stearic acid after 3 min, and take it out of the internal mixer after 3 min. After the mixed rubber is cooled to room temperature, open mill it on the two-roll mill, adjust the roll gap to 0.8 mm, add sulfur and accelerator to the rubber sheet. After the rubber compound becomes uniformly black, pass the rubber compound through the mill without wrapping the roll six times, make three triangular bales and three rolls, then adjust the roll gap to more than 6 mm, pass the folded rubber sheet through the roll gap three times, adjust the roll gap to 2.2 mm and take off the sheet, thus obtaining.
[0111] Comparative Example 9
[0112] A method for reinforcing natural rubber:
[0113] The difference from Example 1 is that: prepare 150 parts by mass of natural rubber, 75 parts of cysteamine-grafted carbon black, 2.55 parts of environment-friendly sulfur, 2.55 parts of dibenzothiazole disulfide (DM), 4.5 parts of stearic acid, 3 parts of N-isopropyl-N'-phenyl-p-phenylenediamine (4020), and 7.5 parts of zinc oxide.
[0114] Perform the following performance tests on the reinforced natural rubber of the above examples and comparative examples. The specific test results are shown in Table 1:
[0115] (1) Hardness test: The Shore hardness is tested according to the standard GB / T 531.1-2008. The larger the index, the higher the hardness;
[0116] (2) Tensile strength test: The tensile strength is tested according to the standard GB / T 528-2009. The larger the index, the higher the tensile strength;
[0117] (3) 300% modulus test: The 300% modulus is tested according to the standard GB / T 528-2009. The larger the index, the higher the tensile modulus.
[0118] (4) Bound rubber test: Test the mixed rubber according to the swelling method. The larger the index, the higher the bound rubber.
[0119] (5) Compression heat build-up test: According to GB / T 1687.3-2016, the vulcanized rubber specimen was cut into a cylindrical shape with a diameter of 17.8 mm and a height of 25 mm. The smaller the index, the lower the compression heat build-up.
[0120] Table 1 Comparison of performance test results of the reinforced natural rubber obtained in the examples and comparative examples
[0121]
[0122] As can be seen from Table 1, for the modified pyrolytic carbon black reinforced natural rubber provided in Examples 1-4 of the present invention, indicators such as hardness, tensile strength, 300% modulus at elongation, bound rubber and compression heat build-up have been greatly improved compared with Comparative Example 2 which only uses unmodified pyrolytic carbon black. And with the increase of the addition ratio of cystamine grafted carbon black, the reinforcing effect first increases and then decreases, but all have good reinforcing properties.
[0123] Compared with Comparative Example 4, it can be seen that graft modification is more effective in reinforcing rubber than physical mixing.
[0124] Compared with Comparative Examples 3, 5 and 6, it can be seen that the modified carbon black can reach the level of some commercial carbon blacks (such as N660) and silane coupling agents Si69 and KH550.
[0125] Compared with Comparative Examples 7 and 8, it can be seen that the silica content has a quite large difference in the rubber reinforcing performance, and the effect is significant when the silica content is controlled at 4-10% by adding an appropriate amount of hydrofluoric acid.
[0126] Compared with Comparative Examples 1 and 9, it can be seen that when both the silicon-activated carbon black and cystamine grafted carbon black are present in the formulation, the effect of reinforcing rubber is better.
[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or equivalently replace some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. In addition, those skilled in the art can understand that although some embodiments herein include some features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of the present invention and forms different embodiments. For example, in the claims above, any one of the claimed embodiments can be used in any combination. The information disclosed in this background art section is only intended to deepen the understanding of the overall background art of the present invention, and should not be regarded as an admission or any form of suggestion that this information constitutes prior art known to those skilled in the art.
Claims
1. A preparation method of modified pyrolytic carbon black, characterized in that, The preparation method comprises the following steps: S1: Subject the pyrolytic carbon black to pretreatment in a liquid dispersion system comprising an acid cleaning agent, an oxidizing agent and a surfactant, then wash, filter and dry to obtain silicon-containing activated carbon black; S2: Disperse the silicon-containing activated carbon black in a solvent, add an acyl chlorination reagent and a catalyst 1 and react to obtain acyl chlorinated carbon black; S3: Add a cystamine coupling agent to modify the surface of the acyl chlorinated carbon black to obtain the modified pyrolytic carbon black.
2. The preparation method of the modified pyrolytic carbon black according to claim 1, wherein, In step S1, the silicon dioxide content of the silicon-containing activated carbon black is 4-10%.
3. The preparation method of the modified pyrolytic carbon black according to claim 1, characterized in that, In step S1, the acid cleaning agent comprises an inorganic acid and / or an organic acid, and the concentration of the acid cleaning agent in the liquid dispersion system is 1-5M; And / or, the oxidizing agent comprises one or more of hydrogen peroxide, potassium permanganate, ammonium persulfate or potassium dichromate, and the concentration of the oxidizing agent in the liquid dispersion system is 2-8M; And / or, the surfactant includes one or more of sodium dodecyl sulfonate, sodium dodecylbenzenesulfonate, cetyltrimethylammonium bromide or sodium stearate, and the concentration of the surfactant in the liquid phase dispersion system is 0.1-2 g·L -1 ; And / or, the temperature of the pretreatment is 50-90°C; And / or, the solid-liquid ratio of the pyrolytic carbon black to the liquid dispersion system is 1g:5-20mL.
4. The preparation method of the modified pyrolytic carbon black according to claim 1, characterized in that, In step S2, the acyl chlorination reagent comprises one or more of thionyl chloride, oxalyl chloride or phosphorus trichloride; And / or, the catalyst 1 comprises triethylamine and / or 4-dimethylaminopyridine; And / or, the solvent is one or more of toluene, xylene, chlorobenzene, dichloromethane, DMF, ethanol or tetrahydrofuran; And / or, the dosage ratio of the silicon-containing activated carbon black, the acyl chlorination reagent, the catalyst 1 and the solvent is 50-100g:12.5-25g:0.5-1.0mL:250-500mL; And / or, the temperature of the reaction is 0-160°C.
5. The preparation method of the modified pyrolytic carbon black according to claim 1, characterized in that, In step S3, the mass ratio of the acyl chlorinated carbon black to the cystamine coupling agent is 10-70:1.48-10.36; And / or, the temperature of the surface modification is 0-120°C.
6. The preparation method of the modified pyrolytic carbon black according to claim 5, characterized in that, In step S3, an alkali, a solvent and a catalyst 2 are further added; The dosage ratio of the acyl chlorinated carbon black, the cystamine coupling agent, the alkali and the solvent is 10-70g:1.48-10.36g:0.77-5.37g:50-365mL; The mass of the catalyst 2 is 5-15% of the mass of the acyl chlorinated carbon black.
7. A method for reinforcing natural rubber based on the preparation method according to any one of claims 1-6, characterized in that, After the natural rubber is kneaded in a Banbury mixer, add the cystamine grafted carbon black, antioxidant, zinc oxide and stearic acid and knead; then add sulfur and accelerator and open mill to obtain the product.
8. The method for reinforcing natural rubber according to claim 7, wherein The natural rubber, cystamine grafted carbon black, antioxidant, zinc oxide, stearic acid, sulfur and accelerator are 150 parts, 10-70 parts, 3-6 parts, 3-7.5 parts, 4.5-9 parts, 2.55-5.1 parts and 2.55-5.1 parts by mass respectively.
9. The method for reinforcing natural rubber according to claim 8, wherein, When or after adding the cystamine grafted carbon black, add 5-65 parts of the silicon-containing activated carbon black.
10. The method for reinforcing natural rubber according to claim 7, wherein The accelerator comprises one or more of dibenzothiazole disulfide, 2-mercaptobenzothiazole, N-cyclohexyl-2-benzothiazole sulfenamide or diphenyl guanidine; And / or, the antioxidant comprises one or more of N-isopropyl-N'-phenyl-p-phenylenediamine, N-phenyl-α-naphthylamine or 2,6-di-tert-butyl-4-methylphenol.