Preparation method of precipitated silica for new energy vehicle tires

Abstract

This invention discloses a method for preparing precipitated silica for new energy vehicle tires, comprising the following steps: 1. Adding tap water to the reaction vessel as the base liquid at a mass ratio of tap water: emulsified hydrogen-containing silicone oil = 1:(0.0005-0.0015), using sodium silicate solution as the alkaline solution and sulfuric acid solution as the acid solution; 2. 9-10m 3 Add alkali solution at a flow rate of 0.75–0.80 m³ / h. 3 Add acid solution at a flow rate of 6-7 m / h and react for 25-40 min, controlling the pH at 8.5-9.0, while stirring; 3. Add alkali solution at a flow rate of 6-7 m / h. 3 / h, acid flow rate 0.55-0.60m 3 React for 30-55 minutes per hour, controlling the pH at 8.5-9.0, stirring; 4. Stir at 9-10 ml / min. 3 Add alkali solution at a flow rate of 0.75–0.80 m³ / h. 3 Add acid at a flow rate of / h and react for 55-70 minutes, controlling the pH at 8.5-9.0, stirring. 5. After the reaction, add acid to adjust the pH of the suspension to 7.0-7.5, stirring. 6. Continue adding acid to adjust the pH of the suspension to 3.5-4.0, aging. 7. The suspension is washed, separated from solids, slurried, and spray-dried to obtain silica for new energy vehicle tires. This invention has good dispersibility, stable performance, low cost, and high production efficiency, meeting the requirements of new energy vehicle tires for low rolling resistance and high grip.

Description

Technical Field

[0001] This invention relates to the technical field of precipitated silica production methods, specifically to a method for preparing precipitated silica for new energy vehicle tires. Technical Background

[0002] With the rapid development of new energy vehicles, the performance requirements for their supporting tires are also increasing. New energy vehicle tires not only require lower rolling resistance to significantly improve driving range and meet people's needs for long-distance travel, but also need better grip to ensure driving safety, especially at high speeds and in complex road conditions. As a key filler in rubber tires, the performance of silica directly affects the quality of the tire. Currently, the most prominent quality problem with silica is insufficient dispersibility. Poor dispersibility of silica in rubber prevents it from fully exerting its reinforcing effect, thus affecting tire performance. Specifically: first, it is difficult to reduce the rolling resistance of the tire to an ideal level, which not only increases energy consumption and reduces driving range, but also contradicts the energy-saving and environmentally friendly concept of new energy vehicles; second, grip is also difficult to improve effectively, affecting driving safety; and third, it leads to a decline in tire wear resistance, aging resistance, and other properties, shortening the tire's service life.

[0003] Currently, precipitation is one of the commonly used methods for preparing silica, but existing methods for preparing precipitated silica for new energy vehicle tires have many limitations:

[0004] The manufacturing process of highly dispersible silica for green tires disclosed in CN103435051B has a large temperature difference between the first and second reaction steps, resulting in a wide range of product particle sizes. This leads to poor dispersion performance of the silica product, which cannot meet the requirements of green tires for highly dispersible silica.

[0005] CN115321548A discloses a method for preparing highly dispersed silica for new energy vehicle tires. The precipitated silica obtained still needs to be modified before it can be used as a tire reinforcement material. Its product quality and stability are not good, and the tire reinforcement cannot meet expectations.

[0006] CN113905985A discloses a precipitated silica for green tires and its preparation method. It adopts a staged solid-liquid separation process, which is complex and requires precise control of the pH value at each stage. It has high requirements for equipment and personnel, which increases the difficulty and cost of production, resulting in reduced production efficiency and is not conducive to large-scale production.

[0007] Therefore, it is necessary to develop a method for preparing precipitated silica suitable for new energy vehicle tires to overcome the shortcomings of existing technologies and prepare silica with good dispersibility, excellent performance, good stability, low cost and high production efficiency, so as to meet the requirements of new energy vehicle tires for low rolling resistance and high grip.

[0008] The quality requirements for silica used in new energy vehicle tires are as follows:

[0009] Dispersion: It has good dispersibility, with a dispersion grade of not less than 9.5, which makes it easier to combine with rubber molecules when mixed with rubber, ensuring good dispersion effect and improving the performance of the mixed rubber.

[0010] Rolling resistance: It can effectively reduce the rolling resistance of the tire. Compared with ordinary tires, the rolling resistance is required to be reduced by 10-20%, thereby achieving an energy saving effect of 2%-4%.

[0011] Grip: It has excellent grip, ensuring that the tire can provide reliable traction and handling stability in various road conditions.

[0012] Other properties: It can significantly improve the physical properties of rubber and enhance its tensile strength, etc. Summary of the Invention

[0013] The purpose of this invention is to provide a method for preparing precipitated silica for new energy vehicle tires that has good dispersibility, stable performance, low cost and high production efficiency, so as to meet the requirements of new energy vehicle tires for low rolling resistance and high grip.

[0014] To achieve the above objectives, the preparation method of precipitated silica for new energy vehicle tires of the present invention includes the following steps:

[0015] S1. Preparation of materials for acid-base co-flow reaction: Add tap water and emulsified hydrogen-containing silicone oil as the base liquid to the reactor, with a mass ratio of tap water: emulsified hydrogen-containing silicone oil = 1:(0.0005-0.0015). Control the reactor temperature at 70-75℃. Use a sodium silicate solution with a concentration of 1.20-1.30 mol / L and a modulus of 3.4-3.5 as the alkali solution and a sulfuric acid solution with a mass fraction of 98% as the acid solution.

[0016] S2, First step reaction: with 9-10m 3 Add alkali solution at a flow rate of / h, while simultaneously adding it at a rate of 0.75-0.80m. 3 Add acid solution at a flow rate of / h, react for 25-40min, control the reaction pH at 8.5-9.0, and stir at a frequency of 40-45Hz;

[0017] S3, Second step reaction: Adjust the alkali flow rate to 6-7 m 3 / h, the acid flow rate is adjusted to 0.55-0.60m 3 The reaction time is 30-55 min, the pH is controlled at 8.5-9.0, and the stirring frequency is 50-55 Hz.

[0018] S4, Third step reaction: with 9-10m 3 Add alkali solution at a flow rate of / h, while simultaneously adding it at a rate of 0.75-0.80m. 3 Add acid solution at a flow rate of / h, react for 55-70min, control the reaction pH at 8.5-9.0, and stir at a frequency of 40-45Hz;

[0019] S5. After the co-current reaction is completed, add acid to the reactor to adjust the pH of the suspension to 7.0-7.5, and stir for 0.5-1 hour.

[0020] S6. Continue to add acid to the reactor to adjust the pH of the suspension to 3.5-4.0, and age for 0.5-1 hour;

[0021] S7. The suspension processed in step S6 is washed, separated into solid and liquid, pulped, and spray-dried to obtain silica powder, thus producing a qualified product of precipitated silica for new energy vehicle tires.

[0022] The above-mentioned method for preparing precipitated silica for new energy vehicle tires has the following technical characteristics and beneficial effects:

[0023] 1. Stepwise Reaction Control of Particle Size and Structure: In the preparation of silica, the stepwise reaction in this invention plays a crucial role in the formation and growth of crystal nuclei. In the first step, specific flow rates of alkali and acid solutions and the reaction pH value facilitate the initial formation of silica crystal nuclei. The second step, by adjusting the flow rate and reaction time, controls the growth process of the crystal nuclei, making their particle size distribution more conducive to dispersion in rubber. The third step stabilizes and perfects the structure of the silica. This stepwise reaction can precisely regulate the formation rate and particle size distribution of silica, thereby effectively improving its dispersibility in rubber.

[0024] 2. The role of emulsified hydrogen-containing silicone oil: Hydrogen-containing silicone oil contains a hydrogen-silicon structure. The Si-H bond is easily broken under alkaline conditions. The hydrogen functional groups can interact with the surface of silica, reduce its surface energy, and thus improve the surface properties of silica. This helps to reduce the interaction force between silica particles, reduce the occurrence of agglomeration, significantly improve its dispersibility in rubber, and enable silica to play a more complete reinforcing role.

[0025] 3. Effects of specific acidification and aging steps: After the co-current reaction is completed, the pH of the suspension is first adjusted to 7.0-7.5 and stirred for 0.5-1 hour. Under weakly alkaline conditions, the surface of the silica particles carries a negative charge, which helps to reduce the electrostatic interaction between particles, thereby reducing the tendency to agglomerate. Subsequently, the pH is adjusted to 3.5-4.0 and aged for 0.5-1 hour to further optimize the structure of silica, allowing it to better combine and disperse with rubber molecules, thereby achieving the best dispersion effect and significantly improving tire performance.

[0026] 4. Reaction process setting: The operation steps of this invention are simple, the process parameters are clear, and it is easy to control and operate; the simplicity and controllability of the process are conducive to improving the stability and consistency of the product, reducing the uncertainty in the production process, reducing production costs, improving production efficiency, and making it suitable for large-scale production.

[0027] This invention incorporates emulsified hydrogen-containing silicone oil during the reaction stage and employs a step-by-step, precise reaction control method to make the reaction process more stable and controllable. After the acid-base co-flow reaction is completed, a specific over-acidification and aging treatment process is used. The synergistic effect of each step makes this invention not only simple and easy to implement with high yield, but also produces silica that significantly improves the dispersibility of precipitated silica in rubber. This highly dispersible silica can meet the stringent requirements of new energy vehicle tires for low rolling resistance and high grip, thereby effectively improving tire performance and ensuring the safe and efficient operation of new energy vehicles. Detailed Implementation

[0028] The preparation method of precipitated silica for new energy vehicle tires according to the present invention will be further described in detail below with reference to specific embodiments. The specific steps are as follows:

[0029] Example 1

[0030] S1. Add 60m to the reaction vessel 3 Tap water and 50 kg of emulsified hydrogen-containing silicone oil were used as the base liquid, and the temperature of the reactor was controlled at 72℃. Sodium silicate solution with a concentration of 1.20-1.30 mol / L and a modulus of 3.4-3.5 was used as the alkaline solution, and sulfuric acid solution with a mass fraction of 98% was used as the acid solution.

[0031] S2, at 9.5m 3 Alkali solution was added at a flow rate of / h, while simultaneously at 0.78m 3 Acid solution was added at a flow rate of / h, and the reaction was carried out for 30 minutes, with the reaction pH controlled at 8.8 and the stirring frequency at 45Hz.

[0032] S3. Adjust the alkali solution flow rate to 6.5 m. 3 / h, acid flow rate adjusted to 0.58m 3 / h, react for 40min, control the reaction pH at 8.8, and stir at 55Hz;

[0033] S4. Adjust the alkali solution flow rate to 9.5 m. 3 / h, acid flow rate adjusted to 0.78m 3 / h, react for 60min, control the reaction pH at 8.8, and stir at 45Hz;

[0034] S5. After the three-step acid-base co-flow reaction is completed, add acid to the reactor to adjust the pH of the suspension to 7.2 and stir for 0.8 hours.

[0035] S6. Continue to add acid to the reactor to adjust the pH of the suspension to 3.8 and age for 0.8 hours;

[0036] S7. The treated suspension is washed, separated into solid and liquid, pulped, and spray-dried to obtain silica powder, thus producing a qualified product of precipitated silica for new energy vehicle tires.

[0037] Example 2

[0038] S1. Add 60m to the reaction vessel 3 Tap water and 30 kg of emulsified hydrogen-containing silicone oil were used as the base liquid, and the temperature of the reactor was controlled at 70.5℃. Sodium silicate solution with a concentration of 1.20-1.30 mol / L and a modulus of 3.4-3.5 was used as the alkaline solution, and sulfuric acid solution with a mass fraction of 98% was used as the acid solution.

[0039] S2, with 9m 3 The alkali solution was added at a flow rate of / h, while simultaneously at 0.75m 3 Add acid solution at a flow rate of / h, react for 30min, control the reaction pH at 8.5, and stir at a frequency of 45Hz;

[0040] S3. Adjust the alkali flow rate to 6m. 3 / h, acid flow rate adjusted to 0.55m 3 / h, react for 40min, control the reaction pH at 8.5, and stir at 55Hz;

[0041] S4. Adjust the alkali flow rate to 9m. 3 / h, acid flow rate adjusted to 0.75m 3 / h, react for 60min, control the reaction pH at 8.5, and stir at 45Hz;

[0042] S5. After the three-step acid-base co-flow reaction is completed, add acid to the reactor to adjust the pH of the suspension to 7.0 and stir for 0.5 hours.

[0043] S6. Continue to add acid to the reactor to adjust the pH of the suspension to 3.5 and age for 0.5 hours;

[0044] S7. The treated suspension is washed, separated into solid and liquid, pulped, and spray-dried to obtain silica powder, thus producing a qualified product of precipitated silica for new energy vehicle tires.

[0045] Example 3

[0046] S1. Add 60m to the reaction vessel 3 Tap water and 100 kg of emulsified hydrogen-containing silicone oil were used as the base liquid, and the temperature of the reactor was controlled at 74℃. Sodium silicate solution with a concentration of 1.20-1.30 mol / L and a modulus of 3.4-3.5 was used as the alkaline solution, and sulfuric acid solution with a mass fraction of 98% was used as the acid solution.

[0047] S2, at 10m 3 Alkali solution was added at a flow rate of / h, while simultaneously adding 0.8m 3 Acid solution was added at a flow rate of / h, and the reaction was carried out for 30 minutes, with the pH controlled at 8.5 and the stirring frequency at 43Hz.

[0048] S3. Adjust the alkali flow rate to 7m. 3 / h, acid flow rate adjusted to 0.6m 3 / h, react for 40min, control the reaction pH at 8.5, and stir at 53Hz;

[0049] S4. Adjust the alkaline solution flow rate to 10 m. 3 / h, acid flow rate adjusted to 0.8m 3 / h, react for 60min, control the reaction pH at 8.5, and stir at 43Hz;

[0050] S5. After the three-step acid-base co-flow reaction is completed, add acid to the reactor to adjust the pH of the suspension to 7.5 and stir for 1 hour.

[0051] S6. Continue to add acid to the reactor to adjust the pH of the suspension to 4.0 and age for 1 hour;

[0052] S7. The treated suspension is washed, separated into solid and liquid, pulped, and spray-dried to obtain silica powder, thus producing a qualified product of precipitated silica for new energy vehicle tires.

[0053] Comparative Example 1

[0054] Unlike Example 1, no emulsified hydrogen-containing silicone oil was added in this step, while other conditions were the same as in Example 1.

[0055] Comparative Example 2

[0056] Unlike Example 1, after the three-step acid-base co-current reaction was completed, the step of first acidifying to pH 7.2 and stirring for 0.8 hours was not performed. Instead, the solution was directly acidified to pH 3.8 and aged for 0.8 hours, with other conditions the same as in Example 1.

[0057] Comparative Example 3

[0058] Unlike Example 1, after the three-step acid-base co-current reaction was completed, the solution was first acidified to pH 7.2 and stirred for 0.2 hours, then acidified to pH 3.8 and aged for 0.2 hours. Other conditions were the same as in Example 1.

[0059] Comparative Example 4

[0060] Unlike Example 1, after the three-step acid-base co-current reaction was completed, the solution was first acidified to pH 6.5, stirred for 0.8 hours, then acidified to pH 3.8, and aged for 0.8 hours. Other conditions were the same as in Example 1.

[0061] The test technical indicators of the silica products prepared in the above embodiments and comparative examples are shown in Table 1:

[0062] Table 1 Comparison of testing technical indicators of precipitated silica products prepared in the three examples and four comparative examples.

[0063]

[0064] As can be seen from Table 1, the silica prepared in Examples 1-3 of the present invention has good performance. Compared with the comparative examples, it has significant advantages in terms of specific surface area, oil absorption value, dispersion, grip index, rolling resistance coefficient and tensile strength, which can meet the requirements of new energy vehicle tires for low rolling resistance and high grip.

[0065] This invention improves the dispersibility of silica in rubber through synergistic effects from multiple aspects, thereby significantly improving the performance of new energy tires, reducing rolling resistance, and increasing grip, which can ensure the safe and efficient operation of new energy vehicles.

[0066] It should be noted that the above embodiments are not intended to limit the present invention. Those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing precipitated silica for new energy vehicle tires, characterized in that: It includes the following steps: S1. Preparation of materials for acid-base co-flow reaction: Add tap water and emulsified hydrogen-containing silicone oil as the base liquid to the reactor, with a mass ratio of tap water: emulsified hydrogen-containing silicone oil = 1:(0.0005-0.0015). Control the reactor temperature at 70-75℃. Use a sodium silicate solution with a concentration of 1.20-1.30 mol / L and a modulus of 3.4-3.5 as the alkali solution and a sulfuric acid solution with a mass fraction of 98% as the acid solution. S2, First step reaction: with 9-10m 3 Add alkali solution at a flow rate of / h, while simultaneously adding it at a rate of 0.75-0.80m. 3 Add acid solution at a flow rate of / h, react for 25-40min, control the reaction pH at 8.5-9.0, and stir at a frequency of 40-45Hz; S3, Second step reaction: Adjust the alkali flow rate to 6-7 m 3 / h, the acid flow rate is adjusted to 0.55-0.60m 3 The reaction time is 30-55 min, the pH is controlled at 8.5-9.0, and the stirring frequency is 50-55 Hz. S4, Third step reaction: with 9-10m 3 Add alkali solution at a flow rate of / h, while simultaneously adding it at a rate of 0.75-0.80m. 3 Add acid solution at a flow rate of / h, react for 55-70min, control the reaction pH at 8.5-9.0, and stir at a frequency of 40-45Hz; S5. After the co-current reaction is completed, add acid to the reactor to adjust the pH of the suspension to 7.0-7.5, and stir for 0.5-1 hour. S6. Continue to add acid to the reactor to adjust the pH of the suspension to 3.5-4.0, and age for 0.5-1 hour; S7. The suspension processed in step S6 is washed, separated into solid and liquid, pulped, and spray-dried to obtain silica powder, thus producing a qualified product of precipitated silica for new energy vehicle tires.

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