Preparation method of special composite modified white carbon black for winter tires

Abstract

The invention discloses a preparation method of special composite modified white carbon black for tires in winter, and belongs to the field of white carbon black, and the preparation method comprises the following steps: S1, taking water and a CTAB (Cetyltrimethyl Ammonium Bromide) aqueous solution as a base solution according to a volume ratio, taking a sulfuric acid solution as an acid solution, and taking a sodium silicate solution as an alkali solution; s2, adding an acid-base solution into the base solution for reaction, and then adding ceric ammonium nitrate; s3 and S4, adjusting the acid-base flow rate, the pH value and the stirring frequency step by step; s5, continuously adding the acid solution to adjust the pH value; s6, the suspension liquid in the step S5 is subjected to washing, solid-liquid separation, pulping and spray drying, the dispersity of the white carbon black is improved through CTAB and cerium oxide added in the reaction stage, meanwhile, the pore structure of the white carbon black is adjusted, the binding capacity of the white carbon black and rubber is promoted, the tire has better road holding force and wet skid resistance in the low-temperature environment, and the service life of the tire is prolonged. And the composition can be used as an antioxidant to prolong the service life of rubber tires.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of white carbon black, and particularly relates to a preparation method of a composite modified white carbon black special for winter tires. BACKGROUND

[0002] White carbon black is a general term for white powder X-ray amorphous silicic acid and silicate products, mainly refers to precipitated silica, fumed silica and ultra-fine silica gel. Winter tires are special tires for coping with low temperature, ice and snow and other adverse road conditions, and their performance requirements are significantly different from those of regular driver tires. In a low temperature environment, the rubber matrix hardens and its elasticity decreases, which makes the tire poorly adhere to the road surface. In addition, the friction coefficient of the ice and snow road surface is low, which further aggravates the driving risk. As a key reinforcing filler in the rubber formula of winter tires, the performance of white carbon black will greatly affect the low temperature use effect of the tire, but the precipitated white carbon black for winter tires still has problems of insufficient dispersibility and low temperature compatibility and unreasonable pore structure.

[0003] The conventional precipitated white carbon black has a high content of surface hydroxyl groups and strong polarity, is easy to agglomerate in a non-polar rubber matrix, and has a decreased binding force with rubber molecules in a low temperature environment, which weakens the reinforcing effect and causes the decrease of the elasticity and wet skid resistance of the tire. In addition, the pore volume and pore size of the existing white carbon black products are not optimized for winter tires, and the produced white carbon black cannot effectively adsorb the low temperature plasticizer in the rubber, and the wet skid resistance of the tire is limited. SUMMARY

[0004] (I) Technical problems to be solved In order to overcome the deficiencies of the prior art, the present application provides a preparation method of a composite modified white carbon black special for winter tires, so as to solve the problems of the conventional precipitated white carbon black, such as high content of surface hydroxyl groups, strong polarity, easy agglomeration in a non-polar rubber matrix, decreased binding force with rubber molecules in a low temperature environment, weakened reinforcing effect, and decreased elasticity and wet skid resistance of the tire. In addition, the pore volume and pore size of the existing white carbon black products are not optimized for winter tires, and the produced white carbon black cannot effectively adsorb the low temperature plasticizer in the rubber, and the wet skid resistance of the tire is limited.

[0005] (II) Technical solutions In view of the core requirements of low rolling resistance and high grip of winter tires, the present application provides a composite modified precipitated white carbon black and a preparation method thereof. By depositing cerium oxide on the surface of the white carbon black, the loss factor of the rubber under low temperature conditions is improved, the combination efficiency of the white carbon black and the rubber molecules is promoted, and the wet skid resistance, wear resistance and the like of the tire in a low temperature environment are improved.

[0006] To achieve the above object, the present application realizes the technical scheme as follows: the present application provides a preparation method of composite modified white carbon black special for winter tire, comprising the following steps: S1, acid-base parallel flow reaction preparation: a certain volume ratio of water and CTAB aqueous solution is added to the reaction container, a certain amount of sodium silicate solution is used as lye, a certain amount of sulfuric acid solution is used as acid, and a certain amount of cerium nitrate ammonium is prepared according to the theoretical white carbon black yield to generate cerium oxide; S2, first step reaction: start stirring, add sodium silicate solution to the reaction container at a flow rate of 6.0-7.5 m 3 / h, and add sulfuric acid solution at a flow rate of 4.0-5.5 m 3 / h, control the reaction pH at 5.0-6.0, and add a certain amount of cerium nitrate ammonium at a slower rate; S3, second step reaction: adjust the flow rate of sodium silicate solution to 8.5-9.5 m 3 / h, the flow rate of sulfuric acid solution is 5.0-6.0 m 3 / h, adjust the pH to 8.0-8.5, and increase the stirring frequency, and react for a certain time; S4, third step reaction: keep the reaction pH at 8.0-8.5, increase the stirring frequency again, and react for a certain time; S5, after the parallel flow reaction is completed, sulfuric acid solution is added to the reaction container, the pH is adjusted to 4.5-5.0, and stirring is performed for a certain time; S6, the suspension in step S5 is washed, solid-liquid separated, slurried, and spray dried.

[0007] Further, in S1, water and CTAB aqueous solution with a volume ratio of 1:1-1.5 are added to the reaction kettle, so that the content of CTAB in the reaction container is 7%-10%, the sodium silicate solution accounts for 27%-35% of the total volume of the reaction liquid, and the sulfuric acid solution accounts for 18%-30% of the total volume of the reaction liquid.

[0008] Further, the mass fraction of the sulfuric acid solution is 13%-20%.

[0009] Further, the reaction temperature of S1 to S5 is controlled at 65-85 ℃, and when the reaction is carried out, the normal reaction temperature is relatively high, but when the addition amount of cerium nitrate ammonium is large (such as 30%), it is better to adjust the reaction temperature to be lower.

[0010] Further, in S2, the addition amount of cerium nitrate ammonium is 10%-30% of the theoretical yield of silicon dioxide.

[0011] Further, in S2, the reaction time before adding cerium nitrate ammonium is 20-30 min, and the stirring frequency is 40-45 Hz.

[0012] Further, in the S3, the stirring frequency is 52-55 Hz, and the reaction time is 30-40 min.

[0013] Further, in the S4, the stirring frequency is 55-60 Hz, and the reaction time is 20-30 min, and in the S5, the stirring time is 50 min.

[0014] Further, in the S4, the vinyltriethoxysilane is added as a modifier at a flow rate of 3 m 3 / h, the vinyltriethoxysilane accounts for 4±0.5% of the theoretical yield of the silica, and after the modifier is added, the reaction is continued for 30 min.

[0015] (Three) beneficial effects One of the above technical solutions has the following advantages or beneficial effects: 1. In the preparation process of the white carbon black, the formation and growth of the crystal nucleus are controlled by the step-by-step reaction. In the first step of the reaction, a specific acid-base flow rate and pH are used for operation, which is helpful for the preliminary formation of the white carbon black crystal nucleus; in the second step of the reaction, the flow rate and the reaction time are adjusted to control the crystal nucleus growth process, and cerium nitrate is added to the reaction system, which can generate cerium oxide under acidic conditions and form particles with a size of about 10-20 nm under the action of the CTAB added in the first step, so as to adjust the pore structure and dispersibility of the white carbon black, and also to increase the tan δ of the rubber molecules at -20°C, thereby improving the traction of the tire under low temperature conditions; such step-by-step reaction can accurately understand the generation rate and pore structure of the white carbon black, and effectively improve the dispersibility and combination ability of the white carbon black in the rubber.

[0016] 2. The addition of the CTAB can not only improve the dispersibility of the cerium oxide and the white carbon black, but also can be used as a directing agent to control the particle size of the generated cerium oxide particles, and can also improve the compatibility of the white carbon black and the rubber. In addition, the introduction of the cerium oxide particles can also improve the dispersibility of the white carbon black while adjusting the pore structure of the white carbon black, and promoting the combination of the white carbon black and the rubber molecules.

[0017] The CTAB and the cerium oxide added in the reaction stage can improve the dispersibility of the white carbon black, adjust the pore structure of the white carbon black, and promote the combination ability of the white carbon black and the rubber, so that the tire has better grip and wet skid resistance in a low temperature environment, and can also be used as an antioxidant to improve the service life of the rubber tire. DETAILED DESCRIPTION

[0018] The application will be further described in detail below in conjunction with the examples, but the embodiments of the application are not limited thereto.

[0019] In the scheme, tan delta refers to the loss tangent value of the white carbon black filled rubber composite measured in dynamic mechanical testing, and CTAB refers to cetyltrimethylammonium bromide. In the scheme, the theoretical yield is the mass of the reactant obtained after complete reaction or complete conversion.

[0020] Example One: The application provides a preparation method of a composite modified white carbon black special for winter tires, which comprises the following steps: S1, acid-base parallel flow reaction preparation: adding water and a CTAB solution with a volume ratio of 1:1.4 into a reaction container as a bottom liquid, and controlling the temperature of the reaction container at 65-85 DEG C; adding a sodium silicate solution accounting for 27%-35% of the total volume of the reaction liquid as an alkali solution, and adding a sulfuric acid solution accounting for 18%-30% of the total volume of the reaction liquid as an acid solution, the mass fraction of the sulfuric acid solution is 13%-20%, and preparing cerium ammonium nitrate accounting for 20% of the theoretical white carbon black yield to generate cerium oxide; S2, first step reaction: starting stirring, adjusting the alkali flow rate to 7.5 m 3 / h, adjusting the acid flow rate to 5.4 m 3 / h, controlling the reaction pH to 5.5, and controlling the stirring frequency at 40-45 Hz; after 20-30 min of reaction, cerium ammonium nitrate accounting for 20% of the theoretical yield of silicon dioxide is added within 30 min; S3, second step reaction: the reaction temperature is 85 DEG C, the alkali flow rate is adjusted to 8.6 m 3 / h, the acid flow rate is adjusted to 5.6 m 3 / h, the reaction pH is controlled at 8.0, and the stirring frequency is controlled at 52-55 Hz; after 30-40 min of reaction, S4, third step reaction: the reaction temperature is 85 DEG C, the reaction pH is controlled at 8.5, and the stirring frequency is controlled at 55-60 Hz; after 20-30 min of reaction, S5, after the three-step reaction, the acid solution is added into the reaction container to adjust the pH to 5.0, and stirring is performed for 50 min; S6, the reaction suspension is washed, solid-liquid separated, slurried and spray dried to obtain the cerium oxide-silicon dioxide product.

[0021] Example Two: Compared with Example One: in the embodiment, the volume ratio of the water and the CTAB solution added as the bottom liquid in S1 is adjusted to 1:1, and the remaining conditions and methods remain unchanged.

[0022] Example Three: Compared with Example One: in the embodiment, the cerium ammonium nitrate used to generate cerium oxide in S1 is adjusted to 10% of the theoretical white carbon black yield, and the remaining conditions and methods remain unchanged.

[0023] Example Four: Comparative Example 1: In this example, the volume ratio of water and CTAB solution added in S1 is adjusted to 1:1, and the cerium nitrate ammonium used to generate cerium oxide is adjusted to 10% of the theoretical output of white carbon black, and the flow rate of the base in S2 is adjusted to 6.0 m 3 / h, the flow rate of the acid is 4.0 m 3 / h, and the pH in S3 is 5.0. The flow rate of the base in S3 is 8.5 m 3 / h, and the flow rate of the acid is 5.0 m 3 / h, and the pH in S4 is 8.0. The remaining conditions and methods are unchanged.

[0024] Example Five Comparative Example 1: In this example, the volume ratio of water and CTAB solution added in S1 is adjusted to 1:1.5, and the cerium nitrate ammonium used to generate cerium oxide is adjusted to 30% of the theoretical output of white carbon black. The flow rate of the base in S2 is adjusted to 7.5 m 3 / h, and the flow rate of the acid is adjusted to 5.5 m 3 / h, and the pH is controlled to be 5.5. The stirring frequency is 40-45 Hz, and after the reaction for 20-30 min, 30% cerium nitrate ammonium is added within 30 min. The flow rate of the base in S3 is 9.5 m 3 / h, and the flow rate of the acid is 6.0 m 3 / h, and the pH is adjusted to 8.5. The pH in S4 is 8.5. The remaining conditions and methods are unchanged.

[0025] Example Six Comparative Example 1: In this example, 4±0.5% of vinyltriethoxysilane is added as a modifier after the completion of the reaction in S4. The flow rate is controlled to be 3 m 3 / h. After the addition of the modifier is completed, the reaction continues for a period of time, generally 25-35 min. The remaining conditions and methods are unchanged. After the co-current reaction in S5 is completed, sulfuric acid solution is continuously added to adjust the pH of the reaction system to 4.5-5.0, and stirring is continued for 50 min. The acid conditions can further optimize the structure of the white carbon black and enable the modifier to fully react with the white carbon black, thereby improving the dispersibility and the ability to combine with rubber molecules. The increase of vinyltriethoxysilane can cause a condensation reaction with the hydroxyl groups on the surface of the white carbon black under weak alkaline conditions, forming a covalent bond, which can ensure the close combination of the white carbon black molecules. The vinyltriethoxysilane can also copolymerize with the rubber molecular chains during the vulcanization process of the rubber, forming a three-dimensional crosslinking network of “white carbon black-modifier-rubber”, thereby improving the dispersibility of the white carbon black in the rubber and helping to reduce the rolling resistance of the tire. The vinyltriethoxysilane can improve the elasticity of the tire under low temperature conditions, meet the needs of different winter tires, significantly improve the performance of the tire, and ensure the safety of automobile driving.

[0026] Comparative Example 1: Comparative Example 1, the rest of the conditions and methods remain unchanged.

[0027] Comparative Example 2: Comparative Example 1, the rest of the conditions and methods remain unchanged.

[0028] Table 1: The cerium oxide content of the white carbon black products prepared in the above examples and comparative examples

[0029] Table 2: Comparison of the detection technical indicators of the white carbon black products and vulcanized rubber prepared in the above examples and comparative examples

[0030] It can be seen from Tables 1 and 2 that, in the comparison between Comparative Example 2 and Example 1, when no cerium nitrate ammonium is added, tan δ, dispersity, ice surface friction coefficient at -5℃, 300% modulus and tensile strength are all lower than those after the addition of cerium nitrate ammonium, indicating that cerium nitrate ammonium plays a great role in improving the performance. It can be seen from the comparison between Comparative Example 1 and Example 1 that, when cerium nitrate ammonium is added but no CTAB is added, although tan δ, dispersity, ice surface friction coefficient at -5℃, 300% modulus and tensile strength are improved, the improvement is small. Compared with the scheme of adding CTAB and cerium nitrate ammonium in Example 1, tan δ, dispersity, ice surface friction coefficient at -5℃, 300% modulus and tensile strength are all lower, indicating that CTAB can improve the dispersity of cerium oxide and white carbon black, control the particle size of the generated cerium oxide particles, and improve the compatibility of white carbon black and rubber; It can be seen from Table 2 that the silicon dioxide prepared in Example 1 of the present application has good performance, i.e. using 1:1.4 water and CTAB solution as the base solution and adding 20% of the theoretical white carbon black yield of cerium nitrate ammonium to generate cerium oxide. Compared with the addition amount of other examples, the specific surface area is relatively lower, tan δ at -20℃ is close to 1, the grip of the tire on the icy and snowy road surface can be significantly improved, the ice surface friction coefficient at -5℃ is greatly improved compared with the white carbon black without doping cerium oxide, the friction of the tire on the icy and snowy wet road surface can be enhanced, the 300% modulus and tensile strength are also improved to some extent, the tire can be more fully contacted with the road surface under low-temperature wet conditions, and the anti-wet-skid and high-grip ability of the winter tire is improved in many aspects. After the addition of vinyltriethoxysilane in Example 6, the specific surface area, tan δ and dispersity can be maintained, the elasticity of the tire under low-temperature conditions can be improved, the needs of different winter tires can be met, the performance of the tire can be significantly improved, and the safety of automobile driving can be ensured.

[0031] In the description of the present application, it should be noted that the terms "upper", "lower", "left", "right", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0032] The control mode of the present application is controlled by manually starting and closing the switch, and the wiring diagram of the power element and the provision of the power supply belong to the common knowledge in the art, and the present application is mainly used to protect the mechanical device, so the control mode and the wiring arrangement of the present application will not be explained in detail.

[0033] The above shows and describes the basic principles and main features of the present application and the advantages of the present application, and it is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any mark in the claims should not be regarded as limiting the claims involved. In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A method for preparing a composite modified silica for winter tires, characterized in that: Includes the following steps: S1. Preparation for acid-base co-current reaction: Add a certain volume ratio of water and CTAB aqueous solution to the reaction vessel, use a certain amount of sodium silicate solution as the alkali solution and a certain amount of sulfuric acid solution as the acid solution, and prepare a certain amount of cerium ammonium nitrate to generate cerium oxide based on the theoretical production of silica. S2, First step of the reaction: Start stirring, add sodium silicate solution to the reaction vessel at a flow rate of 6.0-7.5 m³ / h, and simultaneously add it at a flow rate of 4.0-5.5 m³ / h. 3 Add sulfuric acid solution at a flow rate of / h, control the reaction pH at 5.0-6.0, and after a certain reaction time, add a measured amount of cerium ammonium nitrate. S3, Second step reaction: Adjust the flow rate of the sodium silicate solution to 8.5-9.5 m. 3 The flow rate of the sulfuric acid solution is 5.0-6.0 m / h. 3 / h, adjust pH to 8.0-8.5, increase stirring frequency, and react for a certain time; S4. Third step reaction: Keep the reaction pH at 8.0-8.5, increase the stirring frequency again, and react for a certain period of time; S5. After the co-current reaction is completed, add sulfuric acid solution to the reaction vessel, adjust the pH to 4.5-5.0, and stir for a certain period of time. S6. The suspension from step S5 is then washed, separated into solid and liquid, pulped, and spray-dried.

2. The preparation method of a composite modified silica for winter tires according to claim 1, characterized in that: In step S1, water and CTAB aqueous solution with a volume ratio of 1:1-1.5 are added to the reaction vessel, so that the CTAB content in the reaction vessel is 7%-10%, the sodium silicate solution accounts for 27%-35% of the total volume of the reaction liquid, and the sulfuric acid solution accounts for 18%-30% of the total volume of the reaction liquid.

3. The method for preparing a composite modified silica for winter tires according to claim 1 or 2, characterized in that: The sulfuric acid solution has a mass fraction of 13%-20%.

4. The method for preparing a winter tire-specific composite modified silica according to claim 1, characterized in that: The reaction temperatures of S1 to S5 are controlled at 65-85 ℃.

5. The method for preparing a composite modified silica for winter tires according to claim 1, characterized in that: In S2, the amount of cerium ammonium nitrate added is 10%-30% of the theoretical yield of silicon dioxide.

6. A method for preparing a winter tire-specific composite modified silica according to claim 1 or 5, characterized in that: In step S2, the reaction time before adding cerium ammonium nitrate is 20-30 min, and the stirring frequency is 40-45 Hz.

7. A method for preparing a winter tire-specific composite modified silica according to claim 7, characterized in that: In step S3, the stirring frequency is 52-55 Hz and the reaction time is 30-40 min.

8. A method for preparing a winter tire-specific composite modified silica according to claim 7, characterized in that: In step S4, the stirring frequency is 55-60 Hz and the reaction time is 20-30 min. In step S5, the stirring time is 50 min.

9. A method for preparing a winter tire-specific composite modified silica according to any one of claims 2-5 and 8, characterized in that: In S4, with 3 m 3 Vinyltriethoxysilane was added as a modifier at a flow rate of / h, and the reaction continued for 30 min after the modifier was added.

10. The method for preparing a composite modified silica for winter tires according to claim 9, characterized in that: The vinyltriethoxysilane accounts for 4 ± 0.5% of the theoretical yield of silicon dioxide.

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