WO2023097550A1

WO2023097550A1 - Hydrophobic highly-dispersible white carbon black, preparation method therefor, and application thereof

Info

Publication number: WO2023097550A1
Application number: PCT/CN2021/134749
Authority: WO
Inventors: 陈南飞; 卢爱平; 王明贺; 陈辰; 陈家树; 史彤
Original assignee: 无锡恒诚硅业有限公司
Priority date: 2021-12-01
Filing date: 2021-12-01
Publication date: 2023-06-08
Also published as: CN114286801A

Abstract

Hydrophobic highly-dispersible white carbon black, a preparation method therefor, and an application thereof. The preparation method comprises the following steps: (1) mixing a sodium silicate aqueous solution and a silane coupling agent organic solution, and adjusting the pH value to 7-9 during the mixing process to obtain a mixed solution; and (2) dropwise adding an acid solution into the mixed solution obtained in step (1), adjusting the pH value to 4-5, carrying out a precipitation reaction, and then carrying out solid-liquid separation to obtain hydrophobic highly-dispersible white carbon black. By directly mixing a sodium silicate aqueous solution and a silane coupling agent organic solution, sodium silicate reacts in the solution of a silane coupling agent, so that the dispersion effect of the silane coupling agent on white carbon black is improved, and the hydrophobic performance of the finally obtained white carbon black is improved.

Description

A kind of hydrophobic highly dispersed white carbon black and its preparation method and application

technical field

The application belongs to the technical field of inorganic materials, and relates to a preparation method of silicon dioxide, in particular to a hydrophobic high-dispersion white carbon black and its preparation method and application.

Background technique

Silica is hydrated silica, which has good dispersibility, reinforcement, matting, thickening, etc., so it is widely used in industries such as rubber, plastics, coatings, paper, ink, and daily chemicals. As an important reinforcing agent in the rubber industry, silica has a large specific surface area, small particle size, and more free hydroxyl groups on the surface. These free hydroxyl groups can form physical or chemical bonds with rubber molecules to achieve the reinforcing effect. The use of silica in tire treads can significantly reduce the rolling resistance of tires while maintaining good ice and wet skid resistance.

At present, the methods of industrial production of white carbon black include liquid phase precipitation method and gas phase method. The precipitation method uses water glass and inorganic acid as raw materials, and the white carbon black product is obtained through precipitation reaction, aging, washing, drying and granulation. The production process Simple, cheap and easy-to-obtain raw materials, less equipment investment, and low energy consumption. However, the silica prepared by the conventional precipitation method has insufficient dispersibility, and it is difficult to meet the use requirements of tire rubber or high-grade silicone rubber, and there are problems such as serious structure, poor reinforcing effect, and easy yellowing. The gas phase method uses silicon tetrachloride as a raw material and reacts at high temperature to form silicon dioxide. The resulting product has small particle size, high yield and superior performance. However, this method has high energy consumption, low production efficiency, and relatively expensive products.

CN105060304A discloses a method for preparing hydrophobic highly dispersed white carbon black. The method uses water glass and sulfuric acid as raw materials and modifies with silane coupling agent KH570. In the method, the modulus of the water glass is 3.2-3.5, and the concentration of _SiO2 in the water glass is 0.67-2.01mol/L. The concentration of dilute sulfuric acid is 1.5-3.5mol/L. The precipitation reaction temperature is 80-90°C, and the pH value is 3.5-9. The dosage of the modifying agent is 0.1-3% of the total volume of the reaction solution, the modification reaction time is 30-150 minutes, and the final product can be obtained by washing, filtering and drying. The above preparation method improves the problems of many silanol groups on the surface of the white carbon black, easy agglomeration, poor structure and poor compatibility with rubber by modifying the white carbon black. However, since the modifying agent is added after the reaction, the particle size control of the primary particles is limited, and the hydrophobicity of the white carbon black obtained by the preparation method needs to be further improved.

CN103191588A discloses a preparation method of hydrophobic white carbon black, comprising the following steps: (1) preparing a polymer modifier emulsion: adding an emulsifier, dispersing the high molecular weight modifier in deionized water, and preparing a polymer modifier (2) preparation of hydrophobic white carbon black: white carbon black is added to deionized water to obtain a white carbon black suspension, and the concentration of the white carbon black suspension is 5-45%. Mix the polymer modifier emulsion prepared in (1) with the white carbon black suspension, add alkali to adjust the pH value to 7-12, heat to 30-90°C, dry and grind to obtain hydrophobic white carbon black, The reaction time is controlled within 1-5h. It uses an emulsifier to modify the white carbon black, but there is a defect that the white carbon black and the emulsifier are not well mixed; the dispersibility of the white carbon black obtained by the preparation method needs to be further improved.

CN110746794A discloses a kind of preparation method of superhydrophobic white carbon black, comprises the following steps: (1) silane coupling agent, organic solvent and water are mixed by volume ratio 1:(1-8):(1-2) , to obtain a silane coupling agent modification solution; (2) add the silane coupling agent modification solution obtained in step (1) to the silica suspension, and stir at 50-90°C for 0.5-24h; then add non-ionic type surfactant and fluorine-containing polymer, stirred at 40-95°C for 0.5-20h to obtain a composite modified silica suspension; (3) filter the composite modified silica suspension in step (2) , drying, and crushing to obtain superhydrophobic white carbon black. It has low surface energy through the fluorine-containing high molecular polymer, and is firmly combined with the silane coupling agent in the form of covalent bonds. The hydrophobic performance of the modified silica is very good, but the preparation method still adopts The silane coupling agent and organic solvent directly process the silica suspension, and the degree of modification is limited.

Therefore, it is necessary to provide a hydrophobic high-dispersion silica which further improves the hydrophobicity and dispersibility of silica and its preparation method and application.

Contents of the invention

The application provides a hydrophobic high-dispersion white carbon black and its preparation method and application. The preparation method is simple to operate, and the dispersion effect of the white carbon black is improved through process regulation, and the hydrophobic performance of the final white carbon black is improved.

In the first aspect, the application provides a method for preparing hydrophobic highly dispersed silica, the preparation method comprising the following steps:

(1) mixing an aqueous solution of sodium silicate and an organic solution of a silane coupling agent, adjusting the pH value to 7-9 during the mixing process to obtain a mixed solution;

(2) Add acid solution dropwise to the mixed solution obtained in step (1), adjust the pH value to 4-5, carry out precipitation reaction, and then perform solid-liquid separation to obtain the hydrophobic highly dispersed white carbon black.

This application is obtained by directly mixing the sodium silicate aqueous solution and the organic solution of the silane coupling agent, and reacting the sodium silicate in the solvent of the silane coupling agent, which improves the dispersion effect of the silane coupling agent on the Hydrophobic properties of carbon black.

Preferably, the organic solution of the silane coupling agent in step (1) includes an ethanol solution of the silane coupling agent.

Preferably, the concentration of the silane coupling agent organic solution in step (1) is 3-5wt%, such as 3wt%, 3.5wt%, 4wt%, 4.5wt% or 5wt%, but not limited to the listed values , other unlisted values within the value range are also applicable.

Preferably, the silane coupling agent in the organic solution of the silane coupling agent in step (1) includes γ-(methacryloyloxy)propyltrimethoxysilane (KH-570) and/or γ-aminopropyl Triethoxysilane (KH-550).

Preferably, the concentration of the sodium silicate aqueous solution in step (1) is 0.5-2mol/L, such as 0.5mol/L, 0.8mol/L, 1mol/L, 1.2mol/L, 1.5mol/L, 1.8 mol/L or 2mol/L, but not limited to the listed values, other unlisted values within the range of values are also applicable.

Preferably, in the mixed solution described in step (1), the concentration of the silane coupling agent is 0.5-1wt%, such as 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt% or 1wt% , but not limited to the listed values, other unlisted values within the range of values are also applicable.

Preferably, the pH value adjusted in step (1) is adjusted by bubbling CO ₂ .

The alkaline substance includes any one or a combination of at least two of ammonia water, ethylenediamine or triethylamine, typical but non-limiting combinations include ammonia water and ethylenediamine, ethylenediamine and triethylamine A combination of ammonia water and triethylamine, or a combination of ammonia water, ethylenediamine and triethylamine.

Preferably, the temperature of the precipitation reaction in step (2) is 80-85°C, and the time is 30-60min.

The temperature of the precipitation reaction described in this application is 80-85°C, for example, it can be 80°C, 81°C, 82°C, 83°C, 84°C or 85°C, but it is not limited to the listed values, other unlisted values within the range Numerical values also apply.

The precipitation reaction time described in this application is 30-60min, for example, it can be 30min, 35min, 40min, 45min, 50min, 55min or 60min, but it is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

Preferably, the process of the precipitation reaction in step (2) is accompanied by stirring, and the stirring speed is 300-600r/min, such as 300r/min, 350r/min, 400r/min, 450r/min, 500r/min , 550r/min or 600r/min, but not limited to the listed values, other unlisted values within the range of values are also applicable.

Preferably, the solid-liquid separation method in step (2) includes spray drying.

Preferably, the acid solution in step (2) includes citric acid and/or sulfuric acid, preferably a mixed acid of citric acid and sulfuric acid.

Preferably, the mass ratio of citric acid to sulfuric acid is 1:(2-4), such as 1:2, 1:2.5, 1:3, 1:3.5 or 1:4, but not limited to the listed Numerical values, other unrecited numerical values within the numerical range also apply.

Preferably, the temperature of the dropwise acid solution in step (2) is 80-85° C., and the time is 50-60 minutes.

In the step (2) of the present application, the temperature of the acid solution added dropwise is 80-85°C, for example, it can be 80°C, 81°C, 82°C, 83°C, 84°C or 85°C, but it is not limited to the listed values, the range of values Other unlisted values also apply.

The time for adding the acid solution in step (2) of the present application is 50-60min, such as 50min, 51min, 52min, 53min, 54min, 55min, 56min, 57min, 58min, 59min or 60min, but not limited to the listed values , other unlisted values within the value range are also applicable.

Preferably, the process of adding the acid solution in step (2) is accompanied by stirring, and the stirring speed is 300-600r/min, such as 300r/min, 350r/min, 400r/min, 450r/min, 500r /min, 550r/min or 600r/min, but not limited to the listed values, other unlisted values within the range of values are also applicable.

Preferably, the mixed solution in step (1) further includes a modifier.

The modifier includes any one or a combination of at least two of alkylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ethers, or polyol fatty acid esters. Typical but non-limiting combinations include alkylphenol polyoxyethylene ethers. The combination of oxyethylene ether and fatty alcohol polyoxyethylene ether, the combination of fatty alcohol polyoxyethylene ether and polyol fatty acid ester, the combination of alkylphenol polyoxyethylene ether and polyol fatty acid ester, or the combination of alkylphenol polyoxyethylene ether Combination of vinyl ether, fatty alcohol polyoxyethylene ether and polyol fatty acid ester.

Preferably, the concentration of the modifier in the mixed solution in step (1) is 0.1-0.5wt%, such as 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt% or 0.5wt%, but not limited to For the numerical values listed, other unlisted numerical values within the numerical range are also applicable.

As a preferred technical solution of the preparation method described in the first aspect of the present application, the preparation method includes the following steps:

(1) Mix the ethanol solution of sodium silicate aqueous solution and silane coupling agent, blow into _CO in the mixing process Adjust the pH value to be 7-9, obtain mixed solution; The concentration of silane coupling agent in the mixed solution is 0.5-1wt% ;

(2) Under the condition of 80-85°C, add acid solution dropwise to the mixed solution obtained in step (1) for 50-60 minutes, adjust the pH value to 4-5, and the process of adding acid solution is accompanied by stirring, and the stirring speed 300-600r/min; 80-85°C precipitation reaction for 30-60min, the precipitation reaction process is accompanied by stirring, the stirring speed is 300-600r/min; then spray drying to obtain the hydrophobic highly dispersed silica ;

Optionally, the mixed solution in step (1) further includes a modifying agent at a concentration of 0.1-0.5 wt%.

In the second aspect, the present application provides a hydrophobic high-dispersion silica, which is obtained by the preparation method described in the first aspect.

In a third aspect, the present application provides a rubber reinforcing agent, which includes the hydrophobic highly dispersed silica described in the second aspect.

The numerical ranges described in this application not only include the above-mentioned point values, but also include any point values between the above-mentioned numerical ranges that are not listed. Due to space limitations and for the sake of brevity, this application no longer exhaustively lists the described ranges. The specific pip value to include.

Compared with the prior art, the beneficial effects of the present application are:

Detailed ways

The technical solutions of the present application will be further described below through specific implementation methods.

Example 1

The present embodiment provides a kind of preparation method of hydrophobic highly dispersed white carbon black, and described preparation method comprises the following steps:

(1) mix 1.2mol/L sodium silicate aqueous solution and 4wt% silane coupling agent ethanol solution, blow into CO in the mixing process _Adjust pH value to be 8, obtain mixed solution; The concentration of silane coupling agent in the mixed solution is 0.8wt%, and the silane coupling agent is γ-aminopropyltriethoxysilane (KH-550);

(2) Under the condition of 82 DEG C, add acid solution dropwise to the mixed solution obtained in step (1) for 55 minutes, adjust the pH value to 4.5, and the process of adding acid solution is accompanied by stirring, and the stirring speed is 500r/min; 82 Precipitation reaction at ℃ for 45 minutes, the process of precipitation reaction is accompanied by stirring, the stirring speed is 500r/min; then spray drying is carried out to obtain the hydrophobic highly dispersed silica;

The acid solution in step (2) is a mixed acid of citric acid and sulfuric acid, and the mass ratio of citric acid and sulfuric acid is 1:3.

Example 2

(1) mix 0.5mol/L sodium silicate aqueous solution and 3wt% silane coupling agent ethanol solution, blow into _CO in the mixing process Adjust pH value to be 7, obtain mixed solution; The concentration of silane coupling agent in the mixed solution is 0.5wt%, and the silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane (KH-570);

(2) Under the condition of 80 DEG C, in step (1) gained dropwise acid solution 60min, adjust pH value to be 5, the process of dropping acid solution is accompanied by stirring, and the rotating speed of described stirring is 300r/min; 80 Precipitation reaction at ℃ for 60 minutes, the process of precipitation reaction is accompanied by stirring, the stirring speed is 300r/min; then spray drying is carried out to obtain the hydrophobic highly dispersed silica;

The acid solution in step (2) is a mixed acid of citric acid and sulfuric acid, and the mass ratio of citric acid and sulfuric acid is 1:4.

Example 3

(1) mix the sodium silicate aqueous solution of 2mol/L and the silane coupling agent ethanol solution of 5wt%, blow into _CO in the mixing process Adjust pH value to be 9, obtain mixed liquor; The concentration of silane coupling agent in the mixed liquor is 1 wt%, the silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane (KH-570);

(2) under the condition of 85 DEG C, in the mixed solution obtained in step (1), add acid solution dropwise for 30 minutes, adjust the pH value to 4, and the process of adding acid solution is accompanied by stirring, and the rotating speed of the stirring is 600r/min; 85 Precipitation reaction at ℃ for 50 minutes, the process of precipitation reaction is accompanied by stirring, and the rotation speed of the stirring is 600r/min; then spray drying is carried out to obtain the hydrophobic highly dispersed white carbon black;

The acid solution in step (2) is a mixed acid of citric acid and sulfuric acid, and the mass ratio of citric acid and sulfuric acid is 1:2.

Example 4

(1) mix 1.2mol/L sodium silicate aqueous solution, 4wt% silane coupling agent ethanol solution and fatty alcohol polyoxyethylene ether (AEO-9), blow into _CO in the mixing process Adjust the pH value to 8, get Mixed solution; the concentration of silane coupling agent in the mixed solution is 0.8wt%, and the silane coupling agent is γ-aminopropyltriethoxysilane (KH-550); the concentration of AEO-9 in the mixed solution is 0.3 wt%;

Example 5

(1) Mix 1.2mol/L sodium silicate aqueous solution, 4wt% silane coupling agent ethanol solution and alkylphenol polyoxyethylene ether (OP-10), and blow _CO into during the mixing process to adjust the pH value to 8, Obtain mixed solution; The concentration of silane coupling agent is 0.8wt% in mixed solution, and described silane coupled agent is gamma-aminopropyltriethoxysilane (KH-550); The concentration of OP-10 in mixed solution is 0.5wt%;

Example 6

(1) Mix 1.2mol/L sodium silicate aqueous solution, 4wt% ethanol solution of silane coupling agent and polyol fatty acid ester (ZB-60), and blow _CO2 into the mixing process to adjust the pH value to 8 to obtain the mixed liquid; the concentration of silane coupling agent in the mixed solution is 0.8wt%, and the silane coupling agent is γ-aminopropyltriethoxysilane (KH-550); the concentration of ZB-60 in the mixed solution is 0.1wt% %;

Example 7

This example provides a method for preparing hydrophobic highly dispersed silica, except that the acid solution described in step (2) is replaced with citric acid whose pH value is the same as that of the mixed acid, the rest are the same as in Example 1.

Example 8

This example provides a method for preparing hydrophobic highly dispersed silica, except that the acid solution described in step (2) is replaced by sulfuric acid with the same pH as the mixed acid, the rest are the same as in Example 1.

Comparative example 1

This comparative example provides a preparation method of white carbon black, except that in step (1) bubbling CO ₂ to adjust the pH value to 9.5, the rest are the same as in Example 1.

Comparative example 2

This comparative example provides a preparation method of white carbon black, except that the acid solution is used to adjust the pH value to 3.5 in step (2), the rest are the same as in Example 1.

Comparative example 3

This comparative example provides a kind of preparation method of white carbon black, and described preparation method comprises the steps:

(1) bubbling into CO The pH value of the sodium silicate _aqueous solution of regulating 1.2mol/L is 8, obtains mixed solution;

(2) Under the condition of 82 DEG C, add acid solution dropwise to the mixed solution obtained in step (1) for 55 minutes, adjust the pH value to 4.5, and the process of adding acid solution is accompanied by stirring, and the stirring speed is 500r/min; 82 ℃ precipitation reaction for 45min, the process of precipitation reaction is accompanied by stirring, the stirring speed is 500r/min, and the white carbon black slurry is obtained;

(3) Step (2) gained white carbon black slurry and 4wt% silane coupling agent ethanol solution, the concentration of silane coupling agent after mixing is 0.8wt%, and described silane coupling agent is γ-aminopropyl three Ethoxysilane (KH-550); spray drying to obtain white carbon black.

Performance Testing

The BET specific surface area, CTAB specific surface area, oil absorption value and apparent particle diameter D50 of the hydrophobic highly dispersed silica provided in Examples 1-8 and the silica provided in Comparative Examples 1-3 were tested.

The test method of BET specific surface area is carried out according to GB/T 10722-2014 "Nitrogen Adsorption Method for Determination of Total Surface Area and External Area of Carbon Black"; The determination of silicon specific surface area is carried out by CTAB method; the test method of oil absorption value is carried out in accordance with GB/T 3072-2019 "Determination of oil absorption value of precipitated hydrated silica of rubber compounding agent";

The degree of activation is tested as follows: measure 50mL of distilled water and place it in a 100mL beaker, add 1.0g of white carbon black, stir for 30 minutes and let it stand for 24 hours, separate, dry and weigh the white carbon black that sinks to the bottom, and then calculate Activation degree:

Activation degree=[(total mass of white carbon black-mass of white carbon black sinking to the bottom)/total mass of white carbon black]×100%.

The greater the degree of activation, the better the hydrophobic effect, that is, the better the modification effect. The results are shown in Table 1.

Table 1

In summary, this application directly mixes the aqueous solution of sodium silicate and the organic solution of the silane coupling agent to react the sodium silicate in the solvent of the silane coupling agent, which improves the dispersion effect of the silane coupling agent on white carbon black, The hydrophobic performance of the final white carbon black is improved.

The specific embodiments described above have further described the technical solutions and beneficial effects of the application in detail. It should be understood that the above descriptions are only specific embodiments of the application and are not intended to limit the application. Within the spirit and principles, any modifications, equivalent replacements, improvements, etc., shall be included within the scope of protection of this application.

Claims

A preparation method for hydrophobic highly dispersed white carbon black, comprising the steps of:

(1) mixing an aqueous solution of sodium silicate and an organic solution of a silane coupling agent, adjusting the pH value to 7-9 during the mixing process to obtain a mixed solution;

(2) Add acid solution dropwise to the mixed solution obtained in step (1), adjust the pH value to 4-5, carry out precipitation reaction, and then perform solid-liquid separation to obtain the hydrophobic highly dispersed white carbon black.
The preparation method according to claim 1, wherein the organic solution of the silane coupling agent in step (1) comprises an ethanol solution of the silane coupling agent.
The preparation method according to claim 1 or 2, wherein the concentration of the silane coupling agent organic solution in step (1) is 3-5 wt%.
The preparation method according to any one of claims 1-3, wherein the silane coupling agent in the organic solution of the silane coupling agent in step (1) comprises γ-(methacryloyloxy)propyltrimethoxy Silane and/or gamma-aminopropyltriethoxysilane.
The preparation method according to any one of claims 1-4, wherein the concentration of the sodium silicate aqueous solution in step (1) is 0.5-2mol/L;

Preferably, in the mixed liquid described in step (1), the concentration of the silane coupling agent is 0.5-1 wt%.
The preparation method according to any one of claims 1-5, wherein, the adjustment pH value in step (1) is adjusted by bubbling CO 2 .
The preparation method according to any one of claims 1-6, wherein the temperature of the precipitation reaction in step (2) is 80-85°C, and the time is 30-60min;

Preferably, the process of the precipitation reaction in step (2) is accompanied by stirring, and the stirring speed is 300-600r/min;

Preferably, the solid-liquid separation method in step (2) includes spray drying.
The preparation method according to any one of claims 1-7, wherein the acid solution in step (2) comprises citric acid and/or sulfuric acid, preferably a mixed acid of citric acid and sulfuric acid;

Preferably, the mass ratio of said citric acid to sulfuric acid is 1:(2-4);

Preferably, the temperature of the dropwise acid solution in step (2) is 80-85°C, and the time is 50-60min;

Preferably, the process of adding acid solution dropwise in step (2) is accompanied by stirring, and the stirring speed is 300-600r/min.
The preparation method according to any one of claims 1-8, wherein the mixed solution in step (1) also includes a modifying agent;

The modifier includes any one or a combination of at least two of alkylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ethers or polyol fatty acid esters;

Preferably, the concentration of the modifying agent in the mixed solution in step (1) is 0.1-0.5 wt%.
The preparation method according to any one of claims 1-9, wherein the preparation method comprises the steps of:

(1) Mix the ethanol solution of sodium silicate aqueous solution and silane coupling agent, blow into CO in the mixing process Adjust the pH value to be 7-9, obtain mixed solution; The concentration of silane coupling agent in the mixed solution is 0.5-1wt% ;

(2) Under the condition of 80-85°C, add acid solution dropwise to the mixed solution obtained in step (1) for 50-60 minutes, adjust the pH value to 4-5, and the process of adding acid solution is accompanied by stirring, and the stirring speed 300-600r/min; 80-85°C precipitation reaction for 30-60min, the precipitation reaction process is accompanied by stirring, the stirring speed is 300-600r/min; then spray drying to obtain the hydrophobic highly dispersed silica ;

Optionally, the mixed solution in step (1) further includes a modifying agent at a concentration of 0.1-0.5 wt%.
A hydrophobic high-dispersion white carbon black, which is obtained by the preparation method described in any one of claims 1-10.
A rubber reinforcing agent comprising the hydrophobic highly dispersed white carbon black as claimed in claim 11.