Modified pyrolysis carbon black, and preparation method and application thereof

Abstract

The application discloses modified pyrolysis carbon black and a preparation method and application thereof, and belongs to the technical field of rubber additives.The modified pyrolysis carbon black comprises pyrolysis carbon black treated by ball milling, and phytic acid is connected to the surface of the pyrolysis carbon black, and at least part of the phytic acid is connected with a coupling agent; the preparation method of the modified pyrolysis carbon black comprises adding phytic acid and a coupling agent into the pyrolysis carbon black in sequence and ball milling; and the application of the modified pyrolysis carbon black comprises mixing the modified pyrolysis carbon black, non-polar rubber and zinc oxide, and the mass ratio of the zinc oxide to the non-polar rubber is (10-12):100.The modified pyrolysis carbon black provided by the application has the effect of improving the reinforcing effect of the pyrolysis carbon black.

Description

Technical Field

[0001] This invention belongs to the field of resource recycling technology, specifically, it relates to a modified pyrolysis carbon black, its preparation method, and its application. Background Technology

[0002] With social development, the amount of waste rubber tires generated continues to increase. Their difficulty in natural degradation easily causes serious environmental pollution, making waste tire recycling an urgent problem to be solved. Thermal pyrolysis, as a mainstream recycling technology, can convert waste tires into pyrolysis carbon black (PCB), pyrolysis oil, and pyrolysis gas, with pyrolysis carbon black being the core byproduct. However, pyrolysis carbon black has a complex composition, containing not only ash and pyrolysis residues, but also pyrolysis oil adsorbed on its surface. This results in high ash content, a lack of oxygen-containing functional groups on the surface, and low activity. At the same time, it is poorly dispersed in rubber matrices and has weak interfacial bonding. Its reinforcing performance is far inferior to that of industrial virgin carbon black, and it must be modified to achieve high-value utilization. Currently, the traditional modification methods used in industry mainly include dry modification, wet oxidation modification, and coupling agent modification. However, these methods all have insurmountable drawbacks and cannot meet the industry's comprehensive requirements for modification effect and application cost, as detailed below: ① Dry modification: This method, based on mechanical force or high-temperature treatment under solvent-free conditions, can pulverize carbon black agglomerates and activate their surfaces or introduce modifiers. Although this method is simple to operate and has mature industrial applications, its core drawbacks lie in two aspects: extremely uneven surface modification and severe dust pollution. The localized nature of mechanical force leads to significant differences in the degree of carbon black surface activation, and modifiers are difficult to uniformly adhere to the carbon black surface, resulting in large batch-to-batch performance fluctuations. Simultaneously, the dry operation involves no solvents throughout the process, making it easy for ultrafine carbon black dust to escape during processing. This not only pollutes the production environment but also requires additional high-efficiency dust removal equipment, increasing environmental protection investment and operational risks. ② Wet oxidation modification: This method treats carbon black in a liquid environment using an oxidant, introducing polar oxygen-containing functional groups onto the carbon black surface to improve compatibility and remove some impurities. However, the core drawback of this method is the massive amount of waste generated and the high overall cost. Regarding waste emissions, the reaction process produces large amounts of industrial wastewater containing residual oxidants and acidic substances. Some processes also involve the volatilization of acidic gases, and the resulting solid waste requires specialized treatment. The large volume of waste not only presents significant treatment challenges but also imposes severe environmental pressure. In terms of cost, in addition to the high investment required for waste treatment, subsequent cumbersome processes such as filtration, washing, and drying are not only time-consuming but also consume large amounts of water and energy. Combined with the consumption of chemical reagents such as oxidants, the overall modification cost remains high. Furthermore, excessive oxidation can damage the carbon black's structure, further limiting its large-scale application. ③ Coupling agent modification: This method involves grafting coupling agent molecules onto the carbon black surface to create an interfacial bridge, thereby improving the compatibility and bonding strength between carbon black and the polymer matrix. However, the core drawback of this method is the extremely low grafting rate of the coupling agent and the poor stability of the modification effect. The surface of pyrolysis carbon black is highly inert and lacks effective active sites, making it difficult for the coupling agent to adhere efficiently and undergo a grafting reaction. Furthermore, the coupling agent is prone to self-polymerization during the reaction, further reducing the effective grafting efficiency. Insufficient grafting rate directly leads to unsatisfactory modification results. Moreover, factors such as the matching requirements between the coupling agent and the functional groups on the carbon black surface, and the sensitivity of dosage control, cause significant fluctuations in the modification effect between different batches of products, resulting in extremely poor stability and making it difficult to meet the stringent requirements for interfacial bonding strength in high-performance materials. Traditional single modification methods all have shortcomings, so the industry has turned to comprehensive modification using multiple methods in synergy. Among them, dry method + coupling agent composite modification is the most representative technical solution: based on dry method modification, the carbon black agglomerates are first broken down and cracked through dry methods such as mechanical grinding and high temperature activation, the specific surface area of ​​carbon black is expanded and the surface is initially activated. Then, a coupling agent is added in situ to the dry method system. With the help of the shearing and dispersing effect of mechanical force, the coupling agent is made to contact the carbon black surface evenly and achieve grafting. While this composite approach improves the interfacial bonding between carbon black and the polymer matrix through the directional bridging effect of the coupling agent compared to single dry modification, and increases the number of active sites on the carbon black surface and reduces the self-aggregation of the coupling agent, thus improving grafting uniformity, it still has significant limitations. On the one hand, it still relies on mechanical force to achieve dispersion and grafting, making it difficult to fundamentally solve the problem of uneven surface modification; although batch performance fluctuations are alleviated, they are not completely eliminated. On the other hand, the reactivity of the coupling agent is limited in the dry system, resulting in a limited increase in grafting rate, and dust pollution still exists, requiring strict environmental protection measures. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a modified pyrolysis carbon black, its preparation method, and its application.

[0004] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: In a first aspect, there is a modified pyrolysis carbon black (PK-PCB) used as a filler for a non-polar rubber, the non-polar rubber using zinc oxide as a vulcanizing crosslinking agent, comprising ball-milled pyrolysis carbon black, the surface of which is bonded with phytic acid, at least a portion of which is bonded with a coupling agent.

[0005] In this invention, ball milling provides high-energy mechanical force, which can both break up pyrolytic carbon black agglomerates and generate surface free radicals to activate pyrolytic carbon black and induce chemical grafting.

[0006] Generally, coupling agents rely on specific functional groups to react precisely with the active sites on the carbon black surface. However, the number of active sites on the carbon black surface is limited and their distribution is uneven. Coupling agent molecules are mostly single / double functional group structures, resulting in low matching degree with the functional groups on the carbon black surface, making it difficult to form effective chemical bonds. At the same time, grafting coupling agents often requires harsh conditions (such as high-temperature activation and highly polar solvent environments) to activate the reaction activity, and self-polymerization is prone to occur during the reaction, further reducing the effective binding efficiency with the carbon black surface, making grafting significantly more difficult than with phytic acid.

[0007] Refer to the following formula:

[0008] In this invention, the surface of the activated pyrolysis carbon black is mainly composed of carboxyl groups (-COOH), phenolic hydroxyl groups (-OH), and quinone groups, exhibiting overall weak acidity and low hydroxyl density. Phytic acid contains 6 phosphate groups (-PO4H2), each with 2-3 active -OH groups, exhibiting a high density of multifunctional groups that can bind to the activated pyrolysis carbon black at multiple points. Furthermore, the grafting of phytic acid onto the activated pyrolysis carbon black occurs under mild reaction conditions, requiring no high temperature, high pressure, or special solvents. The reaction can proceed rapidly at room temperature to medium temperature in a water / alcohol system. Moreover, the multifunctional structure significantly enhances the contact probability and binding stability with the carbon black surface, making the grafting process efficient and easy to implement.

[0009] In this invention, phytic acid serves to anchor the activated carbon black surface. The coupling agent can form hydrogen bonds with the phosphate group of phytic acid, and the coupling agent is indirectly grafted onto the surface of the pyrolytic carbon black with the help of phytic acid, forming a pyrolytic carbon black-phytic acid-coupling agent structure, which is beneficial to improving the grafting rate, uniformity and connection stability of the coupling agent.

[0010] In this invention, the coupling agent is selected from one of silane coupling agents, titanate coupling agents, aluminate coupling agents, and zirconate coupling agents.

[0011] Specifically, in this invention, the coupling agent is selected from one of the following: aminopropyltriethoxysilane (KH550), glycidyl etheroxypropyltrimethoxysilane (KH560), vinyltrimethoxysilane (KH570), isopropyltrioleoyloxytitanate (NDZ-101), isopropyltris(dioctylpyrophosphoyloxy)titanate (NDZ-201), monoalkoxyunsaturated fatty acid titanate (NDZ-311), distearate isopropoxyaluminate (DL-412), monostearyloxydiisopropoxyaluminate (DL-411), complex fatty acid aluminate (DL-414), tetraisopropylbis(dioctylphosphite)zirconia ester (KR-212), isooctylzirconia ester (KR-138), and zirconium stearate (KR-238).

[0012] More specifically, in this invention, the coupling agent is selected from one of aminopropyltriethoxysilane (KH550), glycidyl etheroxypropyltrimethoxysilane (KH560), isopropyltrioleoyloxytitanate (NDZ-101), and distearate isopropoxyaluminate (DL-412).

[0013] Preferably, the mass ratio of phytic acid to pyrolysis carbon black is (0.5-2.5):100.

[0014] Phytic acid readily forms a very stable zinc phytate complex with zinc oxide. In this invention, when modified pyrolysis carbon black (PK-PCB) is used as a filler to reinforce non-polar rubber, the modified pyrolysis carbon black will retain unreacted free phytic acid. Phytic acid will deprive zinc oxide in the rubber formulation to form a zinc phytate complex. The amount of phytic acid will greatly affect the amount of zinc oxide. When the mass ratio of phytic acid to pyrolysis carbon black is greater than 2.5:100, phytic acid will seriously affect the function of the vulcanization crosslinking agent.

[0015] Preferably, the coupling agent contains an amino group.

[0016] In this invention, the amino group plays the following role: ① The amino group (-NH2) can not only form physical interactions such as hydrogen bonds with the phosphate group of phytic acid, but also undergo chemical reactions to form more stable chemical bonds, such as amide bonds; ②Amino groups can also react efficiently with active sites such as double bonds in natural rubber; ③ The basicity of amino groups can catalyze the sulfidation reaction, which can offset some of the sulfidation delay effect caused by phytic acid consuming zinc oxide.

[0017] When the coupling agent contains amino groups, the resulting modified pyrolysis carbon black (PK-PCB) can further improve the properties of non-polar rubber.

[0018] Specifically, in this invention, the coupling agent is selected from aminopropyltriethoxysilane (KH550).

[0019] Preferably, the mass ratio of the coupling agent to the pyrolysis carbon black is (0.5-5):100.

[0020] In this invention, when the mass ratio of coupling agent to pyrolysis carbon black is greater than 5:100, the coupling agent is difficult to fully react through ball milling alone, which will result in the presence of free unreacted coupling agent in non-polar rubber. This makes the reinforcing effect of modified pyrolysis carbon black (PK-PCB) unpredictable when used to reinforce non-polar rubber.

[0021] Secondly, a method for preparing modified pyrolysis carbon black includes the following steps: S1. Prepare phytic acid into an aqueous solution, and then ball mill it together with pyrolysis carbon black in a ventilated environment; S2. Dissolve the coupling agent in a 20% ethanol aqueous solution and add it to the solution. Continue ball milling, adjusting the pH to 4-5 during the ball milling process. S3. Take the mixture out of the ball mill and perform centrifugal separation, ethanol washing, drying and grinding in sequence to obtain modified pyrolysis carbon black.

[0022] In this invention, the raw materials for preparing modified pyrolysis carbon black are all ball-milled in a liquid environment. Compared with the traditional dry ball milling process, the technical solution adopted in this invention has no dust escape defect. Compared with the traditional wet oxidation modification, the technical solution adopted in this invention does not generate waste. At the same time, the technical solution adopted in this invention can make the coupling agent on the surface of pyrolysis carbon black uniformly distributed.

[0023] In this invention, phytic acid in step S1 has a fast chelation and dissolution rate of metal oxide ash such as Zn, Ca, Fe, and Al on the surface of carbon black and in the shallow mesoporous layer, and the dissolution of metal oxide ash can be achieved without adjusting the pH of the aqueous phase.

[0024] In this invention, phytic acid is used as a polyphosphate chelating agent, and the phosphate groups react with Zn in the ash. 2+ Ca 2+ Fe 3+ Al 3+ Chelating coordination occurs, stripping and coating inorganic ash particles that block mesopore channels, opening up the blocked mesopore openings, and transforming closed and ineffective mesopores into connected and effective mesopores. At the same time, phytic acid grafting introduces a large number of polar hydroxyl groups, widening the wettability of the mesopore channels, allowing rubber molecular chains to penetrate smoothly into the interior of the mesopores. The polar sites on the pore walls form hydrogen bonds and dipole interactions with the rubber, transforming the originally ineffective mesopores with no reinforcing value into effective interface regions that can generate bonded adhesives, thereby simultaneously increasing the effective specific surface area of ​​the filler and the interfacial bonding strength.

[0025] In this invention, phytic acid is used as a polyphosphate chelating agent to react with Zn in the ash. 2+ Ca 2+ Fe 3+ Al 3+ Chelation coordination can prevent phytic acid from filling large amounts of effective mesopores and thus avoid blocking them.

[0026] Preferably, the ball milling speed in step S2 is lower than the ball milling speed in step S1.

[0027] In this invention, the ball milling speed in step S1 is high. High-speed ball milling generates strong shearing, impact, and friction effects, effectively breaking down agglomerated carbon black particles, increasing the specific surface area of ​​the carbon black and exposing active sites. Simultaneously, the strong mechanical action allows phytic acid molecules to rapidly wet and spread on the carbon black surface, making it easier for them to complex and bond with oxygen-containing groups on the carbon black surface, thus improving the uniformity and amount of phytic acid grafting. Furthermore, the high speed activates the carbon black surface through mechanical force, opening up the surface inert structure and generating more active sites, creating conditions for subsequent strong bonding of phytic acid, allowing phytic acid to anchor at multiple points on the carbon black surface.

[0028] In this invention, the ball milling speed in step S2 is lower than that in step S1. Phytic acid has already formed a stable coating and grafting layer on the carbon black surface. If a high speed is used subsequently, the strong mechanical impact can easily peel off and detach the phytic acid molecules already bonded to the surface, destroying the modification effect. Reducing the ball milling speed in the second step can protect the integrity of the phytic acid modified layer from damage. At the same time, the subsequent addition of the coupling agent using a low-speed, low-shear condition will not cause a large amount of self-polymerization of the coupling agent, and can also allow the coupling agent to be evenly distributed on the surface of the carbon black after phytic acid modification, achieving a layered modification effect of phytic acid as a base and coupling agent interface reinforcement, thereby improving the compatibility between carbon black and the rubber matrix.

[0029] The first ball milling at high speed is only for dispersing, activation, and phytic acid grafting; the second ball milling at low speed is only for mixing and coating modification. This avoids excessive grinding that damages the original aggregate structure of carbon black, prevents a decrease in the reinforcing performance of carbon black, and results in a more uniform particle size distribution and better batch stability.

[0030] Preferably, the ball milling speed in step S1 is 350-400 rpm, and the ball milling speed in step S2 is 200-300 rpm.

[0031] Preferably, the phytic acid aqueous solution has a mass fraction of 2.5%.

[0032] Preferably, the drying temperature is ≤120℃.

[0033] In this invention, drying is carried out at ≤120℃. This temperature range avoids thermal decomposition or oxidative cracking of phytic acid and coupling agent molecules, effectively preserving the modified functional groups and interfacial bonding structures already formed on the carbon black surface. This prevents the modified layer from desorbing or falling off due to high temperatures, ensuring the stability of grafting and coating effects. At the same time, it avoids the surface carbonization and micropore collapse problems caused by heating residual light components and trace amounts of cracked oil in pyrolysis carbon black, maintaining the original pore structure and dispersion state of carbon black, inhibiting secondary agglomeration of fine particles due to rapid moisture evaporation, and ensuring the looseness of powder and uniformity of particle size distribution. Furthermore, the low-temperature drying process conditions are gentle and the parameters are easy to control, which can reduce production energy consumption, reduce high-temperature by-product flue gas and odor, improve the consistency of modification effects between batches, and ensure that the modified carbon black still has good dispersibility, interfacial bonding ability and reinforcing properties in the rubber matrix, adapting to the needs of large-scale continuous production.

[0034] Thirdly, an application of modified pyrolysis carbon black involves mixing the modified pyrolysis carbon black, non-polar rubber, and zinc oxide, wherein the mass ratio of zinc oxide to non-polar rubber is (10-12):100.

[0035] When zinc oxide is used, the mass ratio of zinc oxide to non-polar rubber is usually less than 5:100. However, in this invention, the amount of zinc oxide used is more than twice the conventional amount. This invention compensates for the effects of phytic acid by increasing the amount of zinc oxide used.

[0036] Preferably, the mass ratio of the modified pyrolysis carbon black to the non-polar rubber is (20-70):100.

[0037] The amount of pyrolysis carbon black added as a filler to reinforce non-polar rubber is generally <65:100, while in this invention, the mass ratio of modified pyrolysis carbon black to non-polar rubber can exceed 70:100.

[0038] Compared with the prior art, the advantages of the present invention include: the modified pyrolysis carbon black provided by the present invention has a coupling agent indirectly grafted onto the surface of the pyrolysis carbon black by means of phytic acid to form a pyrolysis carbon black-phytic acid-coupling agent structure, which is beneficial to improving the grafting rate, uniformity and connection stability of the coupling agent, and improving the reinforcing effect of the pyrolysis carbon black. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1This is a schematic diagram of the infrared structure characterization of the PCB in this invention and the PK-PCB obtained in Example 8; Figure 2 The X-ray photoelectron spectroscopy (XPS) full spectrum (survey) of the PCB in this invention and the PK-PCB sample obtained in Example 8; Figure 3 The XPS C1s spectra of the PCB in this invention and the PK-PCB sample obtained in Example 8 are shown below. Figure 4 The XPS O1s spectra of the PCB in this invention and the PK-PCB sample obtained in Example 8 are shown below. Figure 5 The XPS N1s spectra of the PCB in this invention and the PK-PCB sample obtained in Example 8 are shown below. Figure 6 The XPS Si1s spectrum of the PK-PCB sample obtained in Example 8 of this invention; Figure 7 This is the XPS P1s spectrum of the PK-PCB sample obtained in Example 8 of this invention. Detailed Implementation

[0041] To enable those skilled in the art to understand the features and effects of this application, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art in this application, and in case of conflict, the definitions in this specification shall prevail.

[0042] The theories or mechanisms described and disclosed herein, whether right or wrong, shall not in any way limit the scope of this application, that is, the content of this application may be implemented without being limited by any particular theory or mechanism.

[0043] In this document, "this application" means "this invention" or "this disclosure".

[0044] The terms “a,” “an,” “a,” or similar expressions are used herein to describe the components and technical features described in this application. Such descriptions are merely for convenience and to provide a general meaning for the scope of this application. Therefore, such descriptions should be understood to include one or at least one, and the singular includes the plural, unless clearly otherwise indicated.

[0045] In this article, "or a combination thereof" means "or any combination thereof", and "any one", "any kind", "any one" means "any one", "any kind", "any one".

[0046] In this document, the terms “comprising,” “including,” “having,” “containing,” or any similar terms are open-ended transitional phrases intended to encompass non-exclusive inclusions. For example, a composition or article thereof containing multiple elements is not limited to the elements listed herein, but may also include other elements not explicitly listed but typically inherent to the composition or article thereof. Furthermore, unless explicitly stated otherwise, the term “or” is an inclusive “or,” not an exclusive “or.” For example, the condition “A or B” is satisfied in any of the following cases: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); A and B are both true (or exist). Moreover, in this document, the terms “comprising,” “including,” “having,” and “containing” are interpreted as specifically disclosed and simultaneously encompassing closed conjunctions such as “composed of,” “consisting of,” “balance of,” and conjunctions such as “substantially composed of,” “mainly composed of,” “mainly composed of,” “essentially containing,” “basically composed of,” “essentially composed of,” “essentially composed of,” and “essentially containing.”

[0047] In this document, all features or conditions defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible subranges and individual numerical values ​​(including integers and fractions) within the ranges, especially integer values. For example, range descriptions such as "1.0 to 8.0," "between 1.0 and 8.0," or "between 1.0 and 8.0" should be considered as specifically disclosing all subranges such as 1.0 to 8.0, 1.0 to 7.0, 2.0 to 8.0, 2.0 to 6.0, 3.0 to 6.0, 4.0 to 8.0, 3.0 to 8.0, etc., and should be considered as covering endpoint values, especially subranges defined by integer values, and should be considered as specifically disclosing individual numerical values ​​within the ranges such as 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, etc. Unless otherwise specified, the foregoing interpretation applies to all contents of this application, whether extensive or not.

[0048] If a quantity, concentration, or other numerical value or parameter is expressed as a range, preferred range (or better range), or a series of upper and lower limits, it should be understood that this document has specifically disclosed all ranges consisting of any pair of upper or preferred values ​​(or better values) and lower or preferred values ​​(or better values) of that range, regardless of whether such ranges are disclosed separately. Furthermore, when a range of numerical values ​​is mentioned herein, unless otherwise stated, the range should include its endpoints and all integers and fractions within the range.

[0049] In this document, numerical values ​​are to be understood as having a precision with significant digits, provided that the purpose of the invention can be achieved. For example, the number 40.0 should be understood to cover the range of 39.50 to 40.49.

[0050] Unless otherwise specified, in this application, a compound refers to a chemical substance formed by two or more elements linked by chemical bonds, including, but not limited to, small molecule compounds and macromolecules. The term "compound" in this document is not limited to a single chemical substance, but can also be interpreted as a class of chemical substances having the same composition or the same properties.

[0051] Unless otherwise specified, in this application, parts by weight represent the relative number of parts by weight in the composition, and can be any unit of weight, such as, but not limited to, kilograms, grams, pounds, etc. For example, 100 parts by weight of polyphenylene ether resin means that it can be 100 kilograms of polyphenylene ether resin or 100 pounds of polyphenylene ether resin.

[0052] It should be understood that the features disclosed in the various embodiments herein can be arbitrarily combined to form the technical solution of this application, as long as there is no contradiction in the combination of these features.

[0053] The present application will be described below with reference to specific embodiments and examples. It should be understood that these specific embodiments and examples are merely illustrative and are not intended to limit the scope or use of the present application.

[0054] Unless otherwise stated, the methods, reagents, and conditions used in the preparation examples, comparative examples, and embodiments described below are conventional methods, reagents, and conditions in the art.

[0055] The following are the details: The carbon content of the pyrolysis carbon black (PCB) is 83.52%, the loss on heating at 125℃ is ≤2.0%, the ash content (825℃) is ≤20.0%, and the residue on a 45μm sieve is ≤2000ppm; Natural rubber (NR) has a tensile strength of 17.4 MPa, a stress at 300% elongation of 8.55 MPa, and a tanδ of 0.1077 at 60℃. Natural rubber (RSS) has a tensile strength of 16.7 MPa, a stress at 300% elongation of 8.23 ​​MPa, and a tanδ of 0.1068 at 60℃. Chlorosulfonated polyethylene (CSM) has a tensile strength of 25.2 MPa, a 300% constant elongation stress of 3.2 MPa, and a tanδ of 0.081 at 60℃. Example 1

[0056] The raw materials used in this embodiment include, by weight, 100 parts of pyrolysis carbon black, 0.5 parts of phytic acid, and 0.5 parts of KH560.

[0057] The preparation method of this embodiment includes: S1. Add pyrolysis carbon black to a planetary ball mill, then prepare phytic acid into a 2.5% phytic acid aqueous solution and add it to the planetary ball mill. Then, ball mill for 2 hours at a speed of 350 rpm, keeping the area around the planetary ball mill unobstructed during the process. S2. Dissolve the coupling agent in a 20% ethanol aqueous solution and add it to a planetary ball mill. Then, ball mill for 2 hours at a speed of 200 rpm. During the process, test the pH of the mixture in the planetary ball mill using a puncture pH electrode at a frequency of 10 min / time, and adjust the pH to 4-5 using a sulfuric acid aqueous solution with pH=1. S3.1 After removing the mixture from the planetary ball mill, centrifuge it at a speed of 4000 rpm for 15 min. S3.2 After centrifugation, remove the solid and rinse it with 200 parts of ethanol. Repeat the operation 3 times. S3.3. The solid washed with ethanol is dried at 80°C for 6 hours and then ground to an average particle size of 5 micrometers to obtain modified pyrolysis carbon black (PK-PCB). Example 2

[0058] The difference between this embodiment and Embodiment 1 is that the raw materials used in this embodiment contain 1.5 parts of phytic acid. Example 3

[0059] The difference between this embodiment and Embodiment 1 is that the raw materials used in this embodiment contain 2.5 parts of phytic acid. Example 4

[0060] The difference between this embodiment and Embodiment 1 is that in this embodiment, 0.5 parts of KH560 are replaced with 0.5 parts of NDZ-101. Example 5

[0061] The difference between this embodiment and embodiment 4 is that the amount of NDZ-101 used in this embodiment is 2 parts. Example 6

[0062] The difference between this embodiment and embodiment 4 is that the amount of NDZ-101 used in this embodiment is 5 parts. Example 7

[0063] The difference between this embodiment and Embodiment 1 is that in this embodiment, 0.5 parts of KH560 are replaced with 0.5 parts of DL-412. Example 8

[0064] The difference between this embodiment and embodiment 3 is that in this embodiment, 0.5 parts of KH560 are replaced with 0.5 parts of KH550.

[0065] Table 1. Amounts of some raw materials used in Examples 1-8 Example 9

[0066] The raw materials used in this embodiment include, by weight, 100 parts of pyrolysis carbon black, 1.5 parts of phytic acid, and 0.5 parts of KH550.

[0067] The preparation method of this embodiment includes: S1. Add pyrolysis carbon black to a planetary ball mill, then prepare phytic acid into a 2.5% phytic acid aqueous solution and add it to the planetary ball mill. Then, ball mill for 2 hours at a speed of 400 rpm, keeping the area around the planetary ball mill unobstructed during the process. S2. Dissolve the coupling agent in a 20% ethanol aqueous solution and add it to a planetary ball mill. Then, ball mill for 2 hours at a speed of 300 rpm. During the process, test the pH of the mixture in the planetary ball mill using a puncture pH electrode at a frequency of 10 min / time. Adjust the pH to 4-5 using a sulfuric acid aqueous solution with pH=1. S3.1 After removing the mixture from the planetary ball mill, centrifuge it at a speed of 4000 rpm for 15 min. S3.2 After centrifugation, remove the solid and rinse it with 200 parts of ethanol. Repeat the operation 3 times. S3.3. The solid washed with ethanol is dried at 120°C for 2 hours and then ground to an average particle size of 5 micrometers to obtain modified pyrolysis carbon black.

[0068] Comparative Example 1 The raw materials used in this comparative example include, by weight, 100 parts of pyrolysis carbon black and 0.5 parts of KH560.

[0069] The preparation method of this comparative example includes: D1. Add pyrolysis carbon black to a planetary ball mill, then add 20 parts of water to the planetary ball mill, and then ball mill for 2 hours at a speed of 350 rpm, keeping the area around the planetary ball mill unobstructed during the process. D2. Dissolve the coupling agent in a 20% ethanol aqueous solution and add it to a planetary ball mill. Then, ball mill for 2 hours at a speed of 200 rpm. During the process, test the pH of the mixture in the planetary ball mill using a puncture pH electrode at a frequency of 10 min / time. Adjust the pH to 4-5 using a sulfuric acid aqueous solution with pH=1. D3.1 After removing the mixture from the planetary ball mill, centrifuge it at a speed of 4000 rpm for 15 min. D3.2 After centrifugation, remove the solid and rinse it with 200 parts of ethanol. Repeat the operation 3 times. D3.3. The solid washed with ethanol was dried at 80°C for 6 hours and then ground to an average particle size of 5 micrometers to obtain modified pyrolysis carbon black.

[0070] Comparative Example 2 The difference between this comparative example and Example 1 is that the raw materials used in this comparative example contain 0.2 parts of phytic acid.

[0071] Comparative Example 3 The difference between this comparative example and Example 1 is that the raw materials used in this comparative example contain 3 parts of phytic acid.

[0072] Comparative Example 4 The difference between this comparative example and Example 6 is that the amount of NDZ-101 used in this comparative example is 6 parts. Example 10

[0073] The raw materials used in this embodiment include, by weight, 100 parts of NR, 10 parts of 800-mesh zinc oxide, and 20 parts of modified pyrolysis carbon black obtained in Example 1.

[0074] The preparation method of this embodiment includes: S1.1. Put NR and modified pyrolysis carbon black into a mixer, turn on the rotor to rotate at 70 rpm and heat to 70°C, then add zinc oxide in 4 batches, mixing for 4 minutes after each addition of zinc oxide. S1.2 After adding zinc oxide, continue mixing for 15 minutes, cool to room temperature, and let stand for 8 hours to obtain the compound. S2. Add the mixed rubber to the open mill and control the temperature at 52℃. Set the roller gap to 2mm and mix for 20 minutes. Then adjust the roller gap to 4mm and produce the rubber sheet. S3. The rubber sheet is vulcanized in a flat vulcanizing machine at a vulcanization temperature of 145℃, a pressure of 12MPa, and a time of 45min. Then it is naturally cooled to room temperature to obtain modified pyrolysis carbon black reinforced rubber. Example 11

[0075] The difference between this embodiment and Embodiment 10 is that the amount of modified pyrolysis carbon black used in this embodiment is 50 parts. Example 12

[0076] The difference between this embodiment and Embodiment 10 is that the amount of modified pyrolysis carbon black used in this embodiment is 70 parts. Example 13

[0077] The difference between this embodiment and Example 10 is that the modified pyrolysis carbon black in this embodiment is derived from Example 2. Example 14

[0078] The difference between this embodiment and Example 10 is that the modified pyrolysis carbon black in this embodiment is derived from Example 3. Example 15

[0079] The difference between this embodiment and embodiment 10 is that the modified pyrolysis carbon black in this embodiment is derived from embodiment 4. Example 16

[0080] The difference between this embodiment and embodiment 10 is that the modified pyrolysis carbon black in this embodiment is derived from embodiment 5. Example 17

[0081] The difference between this embodiment and Example 10 is that the modified pyrolysis carbon black in this embodiment is derived from Example 6. Example 18

[0082] The difference between this embodiment and Example 10 is that the modified pyrolysis carbon black in this embodiment is derived from Example 7. Example 19

[0083] The difference between this embodiment and Example 10 is that the modified pyrolysis carbon black in this embodiment is derived from Example 8.

[0084] Table 2. Information on some of the raw materials used in Examples 10-19 Example 20

[0085] The difference between this embodiment and Example 10 is that in this embodiment, 100 parts of NR are replaced with 100 parts of RSS, 11 parts of 800-mesh zinc oxide, and 50 parts of modified pyrolysis carbon black obtained in Example 9. Example 21

[0086] The difference between this embodiment and Example 10 is that in this embodiment, 100 parts of NR are replaced with 100 parts of RSS, 12 parts of 800-mesh zinc oxide, and 70 parts of modified pyrolysis carbon black obtained in Example 9.

[0087] Comparative Example 5 The difference between this comparative example and Example 10 is that the modified pyrolysis carbon black used in this comparative example is derived from Comparative Example 1.

[0088] Comparative Example 6 The difference between this comparative example and Example 10 is that the modified pyrolysis carbon black used in this comparative example is derived from Comparative Example 2.

[0089] Comparative Example 7 The difference between this comparative example and Example 10 is that the modified pyrolysis carbon black used in this comparative example is derived from Comparative Example 3.

[0090] Comparative Example 8 The difference between this comparative example and Example 10 is that the modified pyrolysis carbon black used in this comparative example is derived from Comparative Example 4.

[0091] Comparative Example 9 The difference between this comparative example and Example 10 is that the amount of modified pyrolysis carbon black used in this comparative example is 15 parts.

[0092] Comparative Example 10 The difference between this comparative example and Example 10 is that the amount of modified pyrolysis carbon black used in this comparative example is 75 parts.

[0093] Comparative Example 11 The difference between this comparative example and Example 10 is that the amount of zinc oxide used in this comparative example is 5 parts.

[0094] Comparative Example 12 The difference between this comparative example and Example 10 is that the amount of zinc oxide used in this comparative example is 9 parts.

[0095] Comparative Example 13 The difference between this comparative example and Example 10 is that the amount of zinc oxide used in this comparative example is 13 parts.

[0096] Table 3. Details of some raw materials used in Comparative Examples 5-13

[0097] Comparative Example 14 The difference between this comparative example and Example 10 is that NR100 copies are replaced with CSM100 copies in this comparative example.

[0098] 1. The modified pyrolysis carbon blacks prepared in Examples 1-9 and Comparative Examples 1-4 were tested according to the following test items: (1) Moisture content / %: According to the provisions of GB / T 3780.8-2019 (125℃, 1h); (2) Carbon content on carbon black surface / %: XPS test was performed using X-ray photoelectron spectroscopy.

[0099] 2. The modified pyrolysis carbon black reinforced rubbers obtained in Examples 10-21 and Comparative Examples 5-14 were tested according to the following test items: (1) Tensile strength: As specified in GB / T 528-2009, unit: MPa; (2) 300% constant elongation stress: in accordance with the provisions of GB / T 528-2009, unit: MPa; (3) 60℃ tanδ: Performed in accordance with GB / T 9870.1-2020 (10Hz, 0.25% strain).

[0100] 3. The pyrolysis carbon black and the modified pyrolysis carbon black obtained in Example 8 were characterized by infrared structure.

[0101] 4. The pyrolysis carbon black and the modified pyrolysis carbon black obtained in Example 8 were subjected to XPS testing.

[0102] Table 4. Moisture content and carbon content of the modified pyrolysis carbon black prepared in Examples 1-9 and Comparative Examples 1-4

[0103] Table 5 shows some properties of the modified pyrolysis carbon black reinforced rubbers prepared in Examples 10-21 and Comparative Examples 5-14.

[0104] Reference Figure 1 , Figure 1 The key data and their explanations are shown in Table 6 below.

[0105] Table 6. Infrared structural characterization data and descriptions of pyrolysis carbon black and modified pyrolysis carbon black obtained in Example 8.

[0106] Figure 1 Key data and explanations: ① Prove that “the two components were successfully grafted” rather than “physically mixed”.

[0107] The spectrum shows that PK-PCB exhibits both the characteristic peaks of KH550 (2925 / 2859) and the characteristic contribution of phytic acid (broad peak enhancement at 3436, POC at 1045 / 1149). The newly added chemical bond (Si-OC / POC) indicates that phytic acid and carbon black are mutually anchored by chemical bonds. If the adsorption of phytic acid and carbon black were merely physical, these characteristic peaks should disappear after washing with ethanol, indicating a strong chemical grafting.

[0108] ② Prove the successful construction of the "organic-inorganic hybrid interface layer".

[0109] The modified carbon black surface has both organosilicon / amino segments provided by KH550 (which helps with compatibility with natural rubber) and polyphosphate groups provided by phytic acid (which provide reactivity and anchoring effect), which helps to improve the fusion ability of carbon black and rubber.

[0110] ③ This provides evidence for the mechanism of "one-step mechanochemical synergistic modification".

[0111] Infrared spectroscopy provides the most direct evidence of the chemical structure of the reaction pathway that provides energy for mechanical force to activate the carbon black surface, anchor phytic acid, and form covalent bonds through KH550 hydrolysis and condensation.

[0112] The reason why modified pyrolysis carbon black improves rubber properties: Phytic acid synergistically modified KH550 pyrolysis carbon black can improve the structure and performance of rubber composites through two core approaches: regulating the surface polarity of carbon black and introducing functional active sites. These approaches optimize interfacial compatibility and regulate vulcanization crosslinking, respectively. The dual mechanisms work together to overcome the inherent defects of virgin pyrolysis carbon black, such as surface inertness and ash pollution, and systematically improve the overall performance of rubber.

[0113] Mechanism of increased polarity: Phytic acid can be stably grafted onto the surface of pyrolytic carbon black through polyhydroxyl and phosphate groups, significantly increasing the surface polarity of the carbon black. This structural change can be verified by infrared spectroscopy, with the sample polarity measured in the range of 3200–3600 cm⁻¹. -1 The significantly enhanced and broadened OH stretching vibration peaks in the region are essentially due to the enrichment of high-density hydroxyl groups on the carbon black surface and the formation of numerous intramolecular and intermolecular hydrogen bond networks. This significant increase in surface polarity brings two key modification effects: First, it effectively strengthens interfacial affinity and compatibility. The modified carbon black can form stable bonds with polar rubber matrices such as CSM, NBR, and CR, as well as polar processing aids such as stearic acid and zinc oxide, through hydrogen bonding and dipole interactions. This effectively inhibits carbon black particle agglomeration and aid migration and precipitation, constructing a uniform and stable filler-rubber interfacial layer, reducing interfacial micro-defects, thereby improving the mechanical load-bearing capacity of the rubber compound and reducing dynamic hysteresis loss and heat generation. Second, it achieves ash passivation and functionalization. For inert ash such as metal oxides and silicates contained in pyrolysis carbon black, the phosphate groups of phytic acid have a strong chelating and coordination ability, and can bind with Zn in the ash. 2+ Ca 2+ When metal ions undergo coordination reactions, they completely coat the ash particles, effectively blocking the physical isolation effect of inert ash on the carbon black skeleton and the rubber matrix, thus solving the interfacial delamination problem caused by ash. Simultaneously, the phytic acid coating on the ash surface carries a large number of polar hydroxyl groups, which can form hydrogen bonds with the rubber matrix, transforming the inert ash impurities that originally harmed the interfacial structure into functional bridging nodes in the filler reinforcement network, significantly improving the stress transfer efficiency of the system.

[0114] Mechanism of Action for Increased Active Sites: The phosphate groups of phytic acid and the amino groups introduced by KH550 can construct a large number of novel active reaction sites on the carbon black surface, playing a dual role in crosslinking and catalytic activation in the rubber sulfur vulcanization system, directly determining the vulcanization characteristics and crosslinking network structure of the rubber compound. Specifically, the -NH2 nucleophilic group carried by KH550 can act as a crosslinking precursor active site, directly participating in the bridging and crosslinking reaction of rubber molecular chains, promoting the rapid growth and formation of the three-dimensional crosslinking network of rubber. The phosphate groups of phytic acid can act as coordination active centers, forming complexes with zinc oxide in the system, effectively activating sulfur components, accelerating the decomposition of sulfur into active sulfur species, and significantly improving the vulcanization reaction activity and rate. These microscopic mechanisms correspond to macroscopic vulcanization test results, effectively shortening the TC90 vulcanization time of the rubber compound and increasing the vulcanization torque difference ΔM, thus accelerating the vulcanization processing efficiency and significantly increasing the crosslinking density of the rubber compound, making the internal crosslinking network of the rubber more uniform and dense. In addition, the amino and phosphate active sites enriched on the surface of carbon black can directly serve as stable chemical and physical cross-linking nodes, further strengthening the overall structural strength and stress transmission capacity of the cross-linking network, and ultimately significantly improving the tear toughness, fatigue resistance and heat aging stability of rubber composites.

[0115] Table 7 XPS test data of PCB and PK-PCB obtained in Example 8

[0116] Reference Figure 2 Table 7 and the meaning of the XPS test data of the PCB and the PK-PCB obtained in Example 8: ①The significant decrease in C content indicates that the carbon black surface is covered with organic matter.

[0117] ②The O content increased significantly, which came from oxygen atoms introduced during the ball milling process, phosphate groups (-PO4) of phytic acid, and silanol groups (Si-OH) of KH550.

[0118] ③The Si content increased, and the Si in the PCB came entirely from the inorganic ash residue of waste tire pyrolysis; the increase in Si content in PK-PCB indicates that KH550 silane coupling agent was introduced into the carbon black surface.

[0119] ④ The phosphorus (P) content increased significantly, whereas P was completely absent in the unmodified PCB. The presence of P in the modified PK-PCB indicates that phytic acid is embedded in the carbon black surface.

[0120] Reference Figure 3-7 The meanings of XPS tests on the PCB and the PK-PCB obtained in Example 8 are shown in Table 8.

[0121] Table 8. Meaning of XPS test results for PCB and PK-PCB obtained in Example 8

[0122] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It should not be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A modified pyrolysis carbon black for use as a filler in non-polar rubber, wherein the non-polar rubber uses zinc oxide as a vulcanizing crosslinking agent, characterized in that, The invention includes ball-milled pyrolysis carbon black, the surface of which is bonded with phytic acid, and at least a portion of which is bonded with a coupling agent.

2. The modified pyrolysis carbon black according to claim 1, characterized in that: The mass ratio of phytic acid to pyrolysis carbon black is (0.5-2.5):

100.

3. The modified pyrolysis carbon black according to claim 1, characterized in that: The coupling agent contains an amino group.

4. The modified pyrolysis carbon black according to claim 1, characterized in that: The mass ratio of the coupling agent to the pyrolysis carbon black is (0.5-5):

100.

5. A method for preparing modified pyrolysis carbon black as described in claim 1, characterized in that, Includes the following steps: S1. Prepare phytic acid into an aqueous solution, and then ball mill it together with pyrolysis carbon black in a ventilated environment; S2. Dissolve the coupling agent in a 20% ethanol aqueous solution and add it to the solution. Continue ball milling, adjusting the pH to 4-5 during the ball milling process. S3. Take the mixture out of the ball mill and perform centrifugal separation, ethanol washing, drying and grinding in sequence to obtain modified pyrolysis carbon black.

6. The method for preparing modified pyrolysis carbon black according to claim 5, characterized in that: The ball milling speed in step S2 is lower than the ball milling speed in step S1.

7. The method for preparing modified pyrolysis carbon black according to claim 6, characterized in that: In step S1, the ball milling speed is 350-400 rpm, and in step S2, the ball milling speed is 200-300 rpm.

8. The method for preparing modified pyrolysis carbon black according to claim 5, characterized in that: The phytic acid aqueous solution has a mass fraction of 2.5%; And / or, the drying temperature is ≤120°C.

9. An application of the modified pyrolysis carbon black as described in claim 1, characterized in that: The modified pyrolysis carbon black, non-polar rubber, and zinc oxide are mixed together, with the mass ratio of zinc oxide to non-polar rubber being (10-12):

100.

10. The application of the modified pyrolysis carbon black according to claim 9, characterized in that: The mass ratio of the modified pyrolysis carbon black to the non-polar rubber is (20-70):100.

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