White carbon black in-situ modification method for reducing VOCs emission and rubber compound
The improved in-situ modification method of silica by pre-hydrolysis-de-alcoholization process solves the problems of poor mixing effect and high VOC emissions in traditional methods, and achieves uniform dispersion of silica in rubber and environmentally friendly VOC emission reduction.
Patent Information
- Application Number
- CN202511245789.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-02
- Publication Date
- 2025-11-14
AI Technical Summary
Traditional in-situ modification methods for silica suffer from poor mixing effects and high difficulty, resulting in high porosity of the finished products. Furthermore, they generate a large amount of volatile organic compounds (VOCs) during rubber processing, affecting the quality and environmental performance of "green tire" production.
A pre-hydrolysis-dealcoholization process using silane coupling agents is employed. By mixing the silane coupling agent with the hydrolysate under acidic conditions and performing dealcoholization treatment, a highly active silane coupling agent is prepared for in-situ modification of silica. Combined with shear force, this improves the dispersibility of silica in rubber and reduces VOC emissions.
It significantly improves the dispersibility and mixing efficiency of silica in rubber, reduces VOC emissions, enhances the performance and environmental value of rubber products, and is suitable for different types of silane coupling agents.
Smart Images
Figure CN120944206A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of rubber processing technology, specifically to a method for in-situ modification of silica to reduce VOC emissions and a compound. Background Technology
[0002] Silica, as an important reinforcing filler, plays a crucial role in rubber processing, especially in the production of "green tires." It can significantly improve the tire's anti-skid performance, reduce rolling resistance and noise, thereby achieving energy conservation and emission reduction goals. However, silica has a high hydroxyl content on its surface, exhibiting high surface polarity and hydrophilicity, which makes it prone to agglomeration and difficult to disperse uniformly during rubber compounding. To address this issue, sulfur-containing silane coupling agents, such as bis(3-triethoxysilylpropyl)tetrasulfide (TESPT), bis(3-triethoxysilylpropyl)disulfide (TESPD), and 3-octanoylthiopropyltriethoxysilane (NXT), are typically added to the rubber compound. In-situ modification processes graft these silane coupling agents onto the silica surface to improve its dispersibility.
[0003] Currently, traditional in-situ modification methods for silica have significant shortcomings in actual production. Firstly, the mixing effect is poor and difficult, resulting in high porosity in the finished product, severely impacting its quality and performance. Secondly, this process generates a large amount of volatile organic compounds (VOCs). According to the U.S. Environmental Protection Agency's "Air Pollutant Emission Factors Compilation," approximately 0.3 kg of non-alcohol VOCs are generated for every ton of rubber mixed in the tire industry. Based on the commonly used "green tire" formulation (rubber: silica: silane coupling agent = 100:80:8), the amount of alcohol VOCs generated from in-situ silica modification for every ton of raw rubber mixed is as high as 40 kg. Therefore, in-situ silica modification has become one of the main sources of VOCs in "green tire" production. Furthermore, the low efficiency and poor effect of rubber mixing, as well as the VOC emissions during the mixing process, have become critical problems that urgently need to be solved in my country's "green tire" industry. In view of this, the present invention proposes a novel in-situ modification method for silica and a compound for reducing VOC emissions, which aims to improve the dispersibility of silica in rubber while significantly reducing VOC emissions and promoting the green development of the rubber processing industry. Summary of the Invention
[0004] The purpose of this invention is to provide a method for in-situ modification of silica and a compound for reducing VOC emissions, so as to solve the obvious shortcomings of the traditional in-situ modification methods of silica mentioned in the background art.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for in-situ modification of silica to reduce VOC emissions, characterized by the following steps: (1) mixing a silane coupling agent with an aqueous dispersion solvent and performing a pre-hydrolysis reaction under acidic conditions to obtain a silane coupling agent hydrolysate; (2) subjecting the hydrolysate to alcohol removal to remove some or all of the alcohols produced by hydrolysis, and adding a polycondensation inhibitor to maintain the reactivity of the hydrolysis products to obtain a highly active silane coupling agent; (3) using the highly active silane coupling agent in the mixing process of rubber and silica to achieve in-situ modification of silica under shear force to obtain a compound.
[0006] Preferably, in the silane coupling agent pre-hydrolysis step, water and a dispersing solvent are prepared into an aqueous dispersion, and the mass concentration of water in the aqueous dispersion is controlled between 0.1% and 99%.
[0007] Preferably, in the silane coupling agent pre-hydrolysis step, the solution pH is adjusted to acidic (pH = 0.1-6), and the solution is continuously stirred at a temperature of 5-70°C to allow the silane coupling agent to reach a specific degree of hydrolysis.
[0008] Preferably, in the de-alcoholization step of the hydrolysate, de-alcoholization is performed by vacuum distillation or reverse osmosis, and a polycondensation inhibitor is added to prevent the silane coupling agent after hydrolysis from undergoing polycondensation and deactivation.
[0009] Preferably, in the in-situ modification step of silica, a highly active silane coupling agent is used to modify the silica, wherein the amount of the highly active silane coupling agent is 0.5% to 15% of the amount of silica.
[0010] Preferably, in the in-situ modification step of the silica, the mixing equipment includes an internal mixer, a two-roll mill, or a screw extruder, and the mixing is carried out at a temperature of 50–190°C for 1–90 minutes.
[0011] Preferably, in the in-situ modification step of the silica, the rubber type includes one or more of natural rubber, styrene-butadiene rubber, isoprene rubber, cis-butadiene rubber, butyl rubber, nitrile rubber, ethylene propylene rubber, or silicone rubber.
[0012] Preferably, in the in-situ modification step of silica, during the preparation of the compound, the silica is modified in-situ by shear force to obtain the compound.
[0013] Preferably, in the in-situ modification step of silica, during the preparation of the compound, the mixing conditions and parameters are controlled to ensure that silica and rubber are fully mixed and in-situ modification is achieved, thereby obtaining the compound.
[0014] Preferably, the silica in the compound is uniformly dispersed in the form of aggregates with an average particle size of less than 3.4 μm, and the number of silica aggregates with a particle size greater than 3.4 μm is less than 10 per 2 mm × 1.5 mm field of view.
[0015] Compared with existing technologies, the beneficial effects of this invention are as follows: The method described in this invention addresses the problems of low rubber mixing efficiency, poor effect, and VOC emissions during the in-situ modification of silica. By utilizing a "pre-hydrolysis-de-alcoholization" process for silane coupling agents to improve the in-situ modification process of silica, the reactivity of silane coupling agents can be effectively increased, thereby improving the in-situ modification effect of silica and the performance of rubber products. It can also reduce VOC emissions during in-situ modification, demonstrating good market prospects and profound environmental value. The method described in this invention explores a novel in-situ modification process for silica, targeting the characteristics of silane coupling agents and the mechanism of silica in-situ modification. It can significantly improve the activity of silane coupling agents while reducing alcohol VOC emissions during silica modification. This method has good technical versatility and is applicable to different types of silane coupling agents. Attached Figure Description
[0016] Figure 1 This is a schematic flowchart of a method for in-situ modification of silica to reduce VOC emissions according to the present invention.
[0017] Figure 2 The image shows the silicon NMR spectra of M1 before and after alcohol removal in the in-situ modification method of silica for reducing VOC emissions according to the present invention.
[0018] Figure 3 The image shows the silicon NMR spectra of M2 before and after alcohol removal in the in-situ modification method of silica for reducing VOC emissions according to the present invention.
[0019] Figure 4 The image shows the silicon NMR spectra of M3 before and after alcohol removal in the in-situ modification method of silica for reducing VOC emissions according to the present invention.
[0020] Figure 5 Payne effect diagram of different compound rubbers for a method of in-situ modification of silica to reduce VOC emissions according to the present invention;
[0021] Figure 6 The diagram shows the ΔG' of different compound rubbers for the in-situ modification method of silica to reduce VOC emissions according to the present invention.
[0022] Figure 7 This is a diagram showing the binder content in different compounded rubbers of a method for in-situ modification of silica to reduce VOC emissions according to the present invention.
[0023] Figure 8 Tg diagrams of different compound rubbers for a method of in-situ modification of silica to reduce VOC emissions according to the present invention.
[0024] Figure 9 The Payne effect diagram of the vulcanized rubber of the in-situ modification method of silica for reducing VOC emissions according to the present invention.
[0025] Figure 10 The diagram shows the ΔG' of different vulcanizates for a method of in-situ modification of silica to reduce VOC emissions according to the present invention.
[0026] Figure 11 The images show micrographs and grayscale images of different vulcanized rubber sections of a method for in-situ modification of silica to reduce VOC emissions according to the present invention (the numbers in the images represent the number of silica aggregates larger than 3.4 μm, and the image size is 2 mm × 1.5 mm). Detailed Implementation
[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0028] Example 1
[0029] Please see Figure 1-11 This invention provides a technical solution: a method for in-situ modification of silica to reduce VOC emissions and a compound, comprising the following steps:
[0030] (1) Pre-hydrolysis of silane coupling agent: Using ethanol as the dispersion solvent, a 20% aqueous dispersion was prepared with distilled water. Then, according to a water-to-silane coupling agent KH580 (MPTS) molar ratio of 1:1, an appropriate amount of the aqueous dispersion was added dropwise to the silane coupling agent at a magnetic stirring speed of 400 rpm, and mixed thoroughly. Formic acid was used as the pH adjuster to adjust the pH of the hydrolysate to 3.5, and the mixture was continuously stirred at room temperature (25℃). The hydrolysis products of KH580 were tested using nuclear magnetic resonance spectroscopy (NMR spectra are shown below). Figure 2 (As shown), after hydrolysis is complete, freeze and store for later use.
[0031] (2) De-alcoholization of hydrolysate: The KH580 hydrolysate was distilled under reduced pressure for 45 minutes at a vacuum of 0.01 MPa and 30°C. The concentration of alcohols in the hydrolysate decreased from 32.7% to 5.3%, with a de-alcoholization rate of 84%. 0.2% acetic acid was added to the hydrolysate to prepare a highly active primary KH580 hydrolysate M1. Its reactivity was determined based on NMR spectroscopy (its NMR spectrum is shown in Figure 1). Figure 2(as shown), and store frozen at -10℃ for later use.
[0032] (3) In-situ modification of silica
[0033] In-situ modification of silica was achieved using a highly active silane coupling agent hydrolysate M1 during the compounding process of SSBR. The specific formulation and process are as follows:
[0034] Basic formula: 137.5 parts of oil-extended solvent-polymerized styrene-butadiene rubber; 60 parts of silica; 4.8 parts of M1; 3.0 parts of zinc oxide; 2.0 parts of stearic acid; 2.0 parts of antioxidant (4020); 3.0 parts of PEG (4000); 1.5 parts of microcrystalline wax; 1.5 parts of sulfur; 1.5 parts of accelerator D; 1.5 parts of accelerator TBBS.
[0035] Mixing Process: A two-stage mixing process is adopted, with a filling coefficient of 0.7 for the internal mixer. The first-stage mixing is set at a temperature of 80℃ and a rotor speed of 90 rpm. First, all the solution-polymerized styrene-butadiene rubber (SSBR) is added to the internal mixer and plasticized for 30 seconds. Then, 3 / 4 of the silica, silane coupling agent, and ZnO are added and mixed for 150 seconds. Finally, the remaining 1 / 4 of the silica, stearic acid (SA), antioxidant 4020, PEG4000, and microcrystalline wax are added. The material is discharged when the temperature of the compound reaches 170℃ or the total time reaches 10 minutes. After resting for 4 hours, the second-stage mixing is set at a temperature of 40℃ and a rotor speed of 60 rpm. The first-stage compound is added to the internal mixer and mixed for 30 seconds. Then, sulfur (S), accelerator (D), and accelerator (TBBS) are added and mixed for 240 seconds before being discharged. The second-stage compound is then sheeted three times longitudinally in an open mill with the mill rollers at room temperature to obtain compound H1.
[0036] Vulcanization process: The compound rubber, which has been left to stand at room temperature for 40 hours, is vulcanized at 165℃ and 24T pressure for a time of T90 to obtain vulcanized rubber S1.
[0037] Example 2
[0038] Please see Figure 1-11 This invention provides a technical solution: a method for in-situ modification of silica to reduce VOC emissions and a compound, comprising the following steps:
[0039] (1) Pre-hydrolysis of silane coupling agent: Using ethanol as the dispersion solvent, a 20% aqueous dispersion was prepared with distilled water. Then, according to a water-to-silane coupling agent KH580 (MPTS) molar ratio of 2:1, an appropriate amount of the aqueous dispersion was added dropwise to the silane coupling agent while magnetically stirring at 400 rpm. After mixing evenly, it was ready for use. Precise hydrolysis of silane coupling agent: Using acetic acid as the pH adjuster, the pH of the evenly stirred hydrolysate was adjusted to 3.5, and the mixture was continuously stirred at room temperature (25℃). The degree of hydrolysis of KH580 was tested using nuclear magnetic resonance spectroscopy (its nuclear magnetic resonance spectrum is shown in Figure 1). Figure 3 (As shown), after hydrolysis is complete, freeze and store for later use.
[0040] (2) De-alcoholization of hydrolysate: Using a reverse osmosis device, KH580 hydrolysate was de-alcoholized for 1 hour at a pressure of 1.2 MPa and a temperature of 25°C. The concentration of alcohols in the hydrolysate decreased from 51.7% to 6.3%, with a de-alcoholization rate of 88%. 0.2% oxalic acid was added to the hydrolysate to prepare a highly active secondary hydrolysate M2 of KH580. Its reactivity was determined based on NMR spectroscopy (its NMR spectrum is shown in Figure 1). Figure 3 (as shown), and store frozen at -10℃ for later use.
[0041] (3) In-situ modification of silica
[0042] In-situ modification of silica was achieved using a highly active silane coupling agent hydrolysate M2 during the compounding process of SSBR. The specific formulation and process are as follows:
[0043] Basic formula: 137.5 parts of oil-extended solvent-polymerized styrene-butadiene rubber; 60 parts of silica; 4.8 parts of M1; 3.0 parts of zinc oxide; 2.0 parts of stearic acid; 2.0 parts of antioxidant (4020); 3.0 parts of PEG (4000); 1.5 parts of microcrystalline wax; 1.5 parts of sulfur; 1.5 parts of accelerator D; 1.5 parts of accelerator TBBS.
[0044] Mixing Process: A two-stage mixing process is adopted, with a filling coefficient of 0.7 for the internal mixer. The first-stage mixing is set at a temperature of 80℃ and a rotor speed of 90 rpm. First, all the solution-polymerized styrene-butadiene rubber (SSBR) is added to the internal mixer and plasticized for 30 seconds. Then, 3 / 4 of the silica, silane coupling agent, and ZnO are added and mixed for 150 seconds. Finally, the remaining 1 / 4 of the silica, stearic acid (SA), antioxidant 4020, PEG4000, and microcrystalline wax are added. The material is discharged when the temperature of the compound reaches 170℃ or the total time reaches 10 minutes. After resting for 4 hours, the second-stage mixing is set at a temperature of 40℃ and a rotor speed of 60 rpm. The first-stage compound is added to the internal mixer and mixed for 30 seconds. Then, sulfur (S), accelerator (D), and accelerator (TBBS) are added and mixed for 240 seconds before being discharged. The second-stage compound is then sheeted three times longitudinally in an open mill with the mill rollers at room temperature to obtain compound H2.
[0045] Vulcanization process: The compound rubber that has been left to stand at room temperature for 40 hours is vulcanized at 165℃ and 24T pressure for a time of T90 to obtain vulcanized rubber S2.
[0046] Example 3
[0047] Please see Figure 1-11 This invention provides a technical solution: a method for in-situ modification of silica to reduce VOC emissions and a compound, comprising the following steps:
[0048] (1) Pre-hydrolysis of silane coupling agent: Using ethanol as the dispersion solvent, a 40% aqueous dispersion was prepared with distilled water. Then, according to a water-to-silane coupling agent KH580 (MPTS) molar ratio of 10:1, an appropriate amount of the aqueous dispersion was added dropwise to the silane coupling agent while magnetically stirring at 400 rpm. After mixing evenly, the solution was set aside. Using acetic acid as the pH adjuster, the pH of the hydrolysate was adjusted to 3.5, and the solution was continuously stirred at room temperature (25℃). The degree of hydrolysis of KH580 was tested using nuclear magnetic resonance spectroscopy (its NMR spectrum is shown in Figure 1). Figure 4 (As shown), after hydrolysis is complete, freeze and store for later use.
[0049] (2) De-alcoholization of hydrolysate: Using a reverse osmosis device, KH580 hydrolysate was de-alcoholized for 1 hour at a pressure of 1.2 MPa and a temperature of 25°C. The concentration of alcohols in the hydrolysate decreased from 71.7% to 7.9%, with a de-alcoholization rate of 89%. 0.3% oxalic acid was added to the hydrolysate to prepare a highly active KH580 tertiary hydrolysate M3. Its reactivity was determined based on NMR spectroscopy (its NMR spectrum is shown in Figure 1). Figure 4 (as shown), and store frozen at -10℃ for later use.
[0050] (3) In-situ modification of silica
[0051] In-situ modification of silica was achieved using a highly active silane coupling agent hydrolysate M3 during the compounding process of SSBR. The specific formulation and process are as follows:
[0052] Basic formula: 137.5 parts of oil-extended solvent-polymerized styrene-butadiene rubber; 60 parts of silica; 4.8 parts of M1; 3.0 parts of zinc oxide; 2.0 parts of stearic acid; 2.0 parts of antioxidant (4020); 3.0 parts of PEG (4000); 1.5 parts of microcrystalline wax; 1.5 parts of sulfur; 1.5 parts of accelerator D; 1.5 parts of accelerator TBBS.
[0053] Mixing Process: A two-stage mixing process is adopted, with a filling coefficient of 0.7 for the internal mixer. The first-stage mixing is set at a temperature of 80℃ and a rotor speed of 90 rpm. First, all the solution-polymerized styrene-butadiene rubber (SSBR) is added to the internal mixer and plasticized for 30 seconds. Then, 3 / 4 of the silica, silane coupling agent, and ZnO are added and mixed for 150 seconds. Finally, the remaining 1 / 4 of the silica, stearic acid (SA), antioxidant 4020, PEG4000, and microcrystalline wax are added. The material is discharged when the temperature of the compound reaches 170℃ or the total time reaches 10 minutes. After resting for 4 hours, the second-stage mixing is set at a temperature of 40℃ and a rotor speed of 60 rpm. The first-stage compound is added to the internal mixer and mixed for 30 seconds. Then, sulfur (S), accelerator (D), and accelerator (TBBS) are added and mixed for 240 seconds before being discharged. The second-stage compound is then sheeted three times longitudinally in an open mill with the mill rollers at room temperature to obtain compound H3.
[0054] Vulcanization process: The compound rubber, which has been left to stand at room temperature for 40 hours, is vulcanized at 165℃ and 24T pressure for a time of T90 to obtain vulcanized rubber S3.
[0055] Example 4 (Comparative Case)
[0056] Using silane coupling agent KH580 as a modifier, in-situ modification of silica was carried out during the compounding process of SSBR. The specific formula and process are as follows:
[0057] Basic formulation: 137.5 parts of oil-extended solvent-polymerized styrene-butadiene rubber; 60 parts of silica; 4.8 parts of silane coupling agent KH580; 3.0 parts of zinc oxide; 2.0 parts of stearic acid; 2.0 parts of antioxidant (4020); 3.0 parts of PEG (4000); 1.5 parts of microcrystalline wax; 1.5 parts of sulfur; 1.5 parts of accelerator D; 1.5 parts of accelerator TBBS.
[0058] Mixing Process: A two-stage mixing process is adopted, with a filling coefficient of 0.7 for the internal mixer. The first-stage mixing is set at a temperature of 80℃ and a rotor speed of 90 rpm. First, all the solution-polymerized styrene-butadiene rubber (SSBR) is added to the internal mixer and plasticized for 30 seconds. Then, 3 / 4 of the silica, silane coupling agent, and ZnO are added and mixed for 150 seconds. Finally, the remaining 1 / 4 of the silica, stearic acid (SA), antioxidant 4020, PEG4000, and microcrystalline wax are added. The material is discharged when the temperature of the compound reaches 170℃ or the total time reaches 10 minutes. After resting for 4 hours, the second-stage mixing is set at a temperature of 40℃ and a rotor speed of 60 rpm. The first-stage compound is added to the internal mixer and mixed for 30 seconds. Then, sulfur (S), accelerator (D), and accelerator (TBBS) are added and mixed for 240 seconds before being discharged. The second-stage compound is then sheeted three times longitudinally in an open mill with the mill rollers at room temperature to obtain compound H0.
[0059] Vulcanization process: The compound rubber, which has been left to stand at room temperature for 40 hours, is vulcanized at 165℃ and 24T pressure for a time of T90 to obtain vulcanized rubber S0.
[0060] Table 1. Vulcanization characteristics of different rubber compounds
[0061]
[0062] Table 2 Mechanical properties of the compound after vulcanization
[0063]
[0064] Analysis of the silane coupling agent hydrolysate in Examples 1-3 above ( Figure 2-4It is evident that the "pre-hydrolysis-de-alcoholization" process can effectively remove over 84% of alcohols from the silane coupling agent hydrolysate. Furthermore, NMR spectroscopy indicates that the de-alcoholized silane coupling agent hydrolysate did not undergo significant polycondensation, maintaining high activity. By controlling factors such as reaction time and water molar ratio, the degree of hydrolysis of the silane coupling agent can be precisely controlled.
[0065] The properties of the compound rubbers and vulcanized rubbers prepared in Examples 1-4 show that, compared with unhydrolyzed silane coupling agents, the compound rubbers prepared with "pre-hydrolyzed-dealcoholized" silane coupling agents exhibit a weaker Payne effect, increased binder content, higher glass transition temperature, shorter vulcanization time, and a weaker Payne effect in the vulcanized rubber, resulting in improved mechanical properties and increased dispersion of silica. Experimental results indicate that in-situ modification of silica using "pre-hydrolyzed-dealcoholized" silane coupling agents can enhance the in-situ modification effect of silica, improve the overall performance of the compound rubbers and vulcanized rubbers, and achieve the highest performance from the secondary hydrolysis products of the silane coupling agent.
[0066] The above four examples clearly demonstrate that improving the in-situ modification process of silica through the "pre-hydrolysis-de-alcoholization" process can not only effectively enhance the reactivity of silane coupling agents, thereby improving the in-situ modification effect of silica and the performance of rubber products, but also reduce VOC emissions during in-situ modification, thus having good market prospects and far-reaching environmental value.
[0067] While some embodiments of the present general inventive concept have been shown and described, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.
Claims
1. A method for in-situ modification of silica to reduce VOC emissions, characterized in that: The process includes the following steps: (1) mixing the silane coupling agent with an aqueous dispersion solvent and performing a pre-hydrolysis reaction under acidic conditions to obtain a silane coupling agent hydrolysate; (2) subjecting the hydrolysate to alcohol removal to remove some or all of the alcohols produced by hydrolysis, and adding a polycondensation inhibitor to maintain the reactivity of the hydrolysis products to obtain a highly active silane coupling agent; (3) using the highly active silane coupling agent in the mixing process of rubber and silica to achieve in-situ modification of silica under shear force to obtain a compound.
2. The method for in-situ modification of silica to reduce VOC emissions according to claim 1, characterized in that: In the silane coupling agent pre-hydrolysis step, water and a dispersing solvent are mixed to form an aqueous dispersion, and the mass concentration of water in the aqueous dispersion is controlled between 0.1% and 99%.
3. The method for in-situ modification of silica to reduce VOC emissions according to claim 1, characterized in that: In the pre-hydrolysis step of the silane coupling agent, the pH of the solution is adjusted to acidic (pH = 0.1-6), and the solution is continuously stirred at a temperature of 5-70°C to allow the silane coupling agent to reach a specific degree of hydrolysis.
4. The method for in-situ modification of silica to reduce VOC emissions according to claim 1, characterized in that: In the de-alcoholization step of the hydrolysate, de-alcoholization is performed by vacuum distillation or reverse osmosis, and a polycondensation inhibitor is added to prevent the silane coupling agent after hydrolysis from undergoing polycondensation and deactivation.
5. The method for in-situ modification of silica to reduce VOC emissions according to claim 1, characterized in that: In the in-situ modification step of the silica, a highly active silane coupling agent is used to modify the silica, wherein the amount of the highly active silane coupling agent is 0.5% to 15% of the amount of silica.
6. The method for in-situ modification of silica to reduce VOC emissions according to claim 1, characterized in that: In the in-situ modification step of the silica, the mixing equipment includes an internal mixer, a two-roll mill or a screw extruder, and the mixing is carried out at a temperature of 50 to 190°C for 1 to 90 minutes.
7. The method for in-situ modification of silica to reduce VOC emissions according to claim 1, characterized in that: In the in-situ modification step of the silica, the rubber type includes one or more of the following: natural rubber, styrene-butadiene rubber, isoprene rubber, cis-butadiene rubber, butyl rubber, nitrile rubber, ethylene propylene rubber, or silicone rubber.
8. The method for in-situ modification of silica to reduce VOC emissions according to claim 1, characterized in that: In the in-situ modification step of the silica, the silica is modified in-situ through shear force during the preparation of the compound to obtain the compound.
9. The method for in-situ modification of silica to reduce VOC emissions according to claim 1, characterized in that: In the in-situ modification step of silica, during the preparation of the compound, the mixing conditions and parameters are controlled to ensure that silica and rubber are fully mixed and in-situ modification is achieved, thus obtaining the compound.
10. The compound prepared by the in-situ modification method of silica for reducing VOC emissions according to claim 1, characterized in that: In the compound, silica is uniformly dispersed in the form of aggregates with an average particle size of less than 3.4 μm, and the number of silica aggregates with a particle size greater than 3.4 μm is less than 10 per 2 mm × 1.5 mm field of view.