Alkaline white carbon black modification method, modified alkaline white carbon black, rubber master batch and preparation method of rubber master batch

Abstract

The invention relates to a modification method of alkaline white carbon black, modified alkaline white carbon black, masterbatch and a preparation method thereof. The modification method comprises the following steps: adding a surfactant and a silane coupling agent into water, adjusting the pH value of the water, and fully reacting to obtain hydrolysate of the silane coupling agent; grinding the alkaline white carbon black slurry to prepare alkaline white carbon black slurry with a certain particle size range; and adding the silane coupling agent hydrolysate into the alkaline white carbon black slurry, and carrying out heating reaction to obtain the modified alkaline white carbon black. According to the method, the agglomeration degree of the alkaline white carbon black can be reduced, the dispersity of the alkaline white carbon black in a material matrix is finally improved, and the stability of a white carbon black wet-process composite latex process can be improved. The masterbatch prepared from the modified alkaline white carbon black disclosed by the invention has relatively strong comprehensive performance.

Description

Technical Field

[0001] The present invention relates to the technical field of white carbon black, and more particularly to a modification method of basic white carbon black and modified basic white carbon black prepared by the modification method. The present invention also relates to a masterbatch filled with modified basic white carbon black and a preparation method thereof. Background Art

[0002] White carbon black, with its high specific surface area and adsorption capacity, is often used as an additive and can be used as a thickener, whitening agent, filler, etc. in various products. Due to the different varieties and production methods of white carbon black, its acidity and alkalinity are also different. The acidity and alkalinity of white carbon black have a great influence on the vulcanization of the rubber compound. The surface of both acidic white carbon black and basic white carbon black contains more silanol groups, which makes them prone to agglomeration, resulting in poor dispersion in the material matrix. In addition, acidic white carbon black will delay the vulcanization of the rubber compound, while basic white carbon black will promote vulcanization. Although basic white carbon black will promote vulcanization, since it has not undergone acidification and polycondensation, it contains more silanol groups, so its agglomeration phenomenon is more serious and its dispersion in the material matrix is poor.

[0003] The wet mixing process is a process of mixing latex and filler in a liquid medium. The wet mixing process solves the shortcomings of the dry mixing process, such as dust pollution, high energy consumption and difficulty in dispersing fillers. However, the stability of the wet compounding latex process of silica is relatively poor, and it is easy to coagulate and precipitate.

[0004] In view of this, developing a modification method for alkaline silica that can reduce the degree of agglomeration of alkaline silica and ultimately improve its dispersibility in the material matrix and improve the stability of the silica wet composite latex process has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a modification method of alkaline silica. On the one hand, a silane coupling agent is hydrolyzed under acidic conditions, and then the alkaline silica within a preset particle size range is modified, and an activator is used in combination, thereby solving the technical problem that the alkaline silica as a filler has poor dispersibility in a material matrix. On the other hand, the modified alkaline silica is wet-compounded with latex to prepare a masterbatch, thereby solving the problems of poor stability and easy demulsification of the wet-compounded silica latex, and ultimately making the rubber have excellent mechanical properties and wear resistance.

[0006] One of the objects of the present invention is to provide a method for modifying basic white carbon black, the modification method comprising:

[0007] (1) adding a surfactant and a silane coupling agent to water, hydrolyzing, and adjusting the pH to 1 to 6 to obtain a silane coupling agent hydrolyzate;

[0008] (2) Pulverize and grind alkaline silica white, water and an activator to obtain an alkaline silica white slurry.

[0009] (3) Mix the hydrolyzate of the silane coupling agent and the alkaline silica white slurry, heat up and react to obtain modified alkaline silica white.

[0010] The present invention can specifically adopt the following technical solutions:

[0011] (1) Add a silane coupling agent and a surfactant to water, stir for a period of time, then add an acid to adjust the pH value, and control the pH value to be 1 - 6 to obtain a hydrolyzate of the silane coupling agent. The acid is selected from at least one of sulfuric acid, hydrochloric acid, acetic acid and nitric acid.

[0012] In this step, the silane coupling agent and the surfactant should be mixed evenly, and observe the dissolution degree of the silane coupling agent. Its good dissolution degree is beneficial to improving the hydrolysis degree of the silane coupling agent. The purpose of adding the surfactant is to make the water-insoluble silane coupling agent dissolve in water for hydrolysis reaction. The main purpose of adding acid treatment is that the acidic condition is beneficial to promoting the hydrolysis of the silane coupling agent, and the self-condensation reaction of the silane coupling agent under acidic conditions is weaker than that under alkaline conditions.

[0013] (2) Add the alkaline silica white filter cake prepared by the carbon dioxide method, water and an activator into a colloid mill for pulping, and first add it to a ball mill for the first grinding treatment. The power of the ball mill is controlled at 40 - 50 Hz. After grinding for a period of time, a first alkaline silica white slurry with a particle size of 2 - 10 μm is obtained; secondly, add the first alkaline silica white slurry with a particle size of 2 - 10 μm into a sand mill for fine grinding. The main shaft speed of the sand mill is controlled at 1000 - 2000 rpm and grind for a period of time; finally, use a classification wheel for classification to obtain the ground alkaline silica white slurry.

[0014] The alkaline silica white has not undergone acidification and condensation and contains more silanol groups. If a silane coupling agent is directly added for modification, the modification effect is poor. In this step, the originally larger-particle-size alkaline silica white is ground to obtain a smaller-particle-size alkaline silica white slurry, which can improve its dispersibility and relative surface area, thereby increasing its contact opportunity with the silane coupling agent and providing more reactive sites for modification, further improving the effect of modifying silica white with the silane coupling agent. In this step, by adding an activator, the viscosity of the alkaline silica white slurry is reduced, making the alkaline silica white slurry easier to flow and disperse. At the same time, the type of activator added is an alkaline activator, which does not affect the acidity and alkalinity of the alkaline silica white slurry.

[0015] (3) Add the hydrolyzate of the silane coupling agent to the ground alkaline silica white slurry, raise the temperature in the intensifying reaction device, and carry out the grafting reaction for a period of time to obtain the modified alkaline silica white slurry.

[0016] In this step, the grafting reaction rate of the silane coupling agent on the surface of the alkaline silica white is increased by raising the reaction temperature, thereby shortening the reaction time. This is because increasing the temperature will increase the kinetic energy of the reactant molecules, resulting in an increase in the collision frequency between molecules, thus increasing the reaction rate. In addition, raising the temperature can also improve the diffusion ability of the reactant molecules, prompting the reactant molecules to approach the reaction center faster, further increasing the reaction rate. Preferably, the intensifying reaction device is any one of a microchannel reactor and a pipe reactor.

[0017] In a preferred embodiment of the present invention,

[0018] the silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, bis-(γ-triethoxysilylpropyl)tetrasulfide, and bis-(γ-triethoxysilylpropyl)disulfide, preferably at least one of γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, and bis-(γ-triethoxysilylpropyl)tetrasulfide; and / or

[0019] the surfactant is at least one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyoxyethylene alkylamine, and polyoxyethylene alkylamide, preferably at least one of fatty alcohol polyoxyethylene ether and fatty acid polyoxyethylene ester; and / or

[0020] the activator is an alkaline activator, and the alkaline activator is preferably at least one of sodium aluminate, sodium hexametaphosphate, sodium hydroxide, and potassium hydroxide, more preferably at least one of sodium aluminate and sodium hexametaphosphate;

[0021] Those skilled in the art can select appropriate silane coupling agents, surfactants, and activators according to the actual situation.

[0022] In a preferred embodiment of the present invention, in step (1), the weight ratio of water, surfactant, and silane coupling agent is 2-6:0.1-2:1, preferably 2.2-4:0.5-1:1; in step (2), the weight ratio of water, activator, and dry weight of basic silica white is 0.83-7.5:0.0001-0.0005:1, preferably 1.5-5:0.0002-0.0004:1; in step (3), the weight ratio of the silane coupling agent in the silane coupling agent hydrolysis solution to the dry weight of the basic silica white in the basic silica white slurry is 0.1-8:100, preferably 0.5-3:100. Those skilled in the art can select a suitable weight ratio according to the actual situation.

[0023] In a preferred embodiment of the present invention, in step (2)

[0024] The particle size of the basic silica white slurry is 2-10 μm, preferably 3-7 μm; and / or

[0025] The solid content of the basic silica white slurry is 10-30 wt%, preferably 14-25 wt%.

[0026] In a preferred embodiment of the present invention, in step (1), the hydrolysis time is 1-20 h, preferably 8-17 h. Those skilled in the art can select a suitable hydrolysis time according to the actual situation to further improve the hydrolysis degree of the silane coupling agent. In step (3), the reaction temperature is 40-95 °C, preferably 45-70 °C; the reaction time is 0.1-3 h, preferably 1-2.5 h. Those skilled in the art can select a suitable reaction temperature and reaction time according to the actual situation to further improve the effect of modifying silica white with the silane coupling agent.

[0027] The second object of the present invention is to provide a modified basic silica white obtained by the modification method of basic silica white of the first object of the present invention.

[0028] The third object of the present invention is to provide a masterbatch filled with the modified basic silica white described in the second object of the present invention. The masterbatch is prepared by uniformly mixing latex and a modified basic silica white slurry and then drying.

[0029] In a preferred embodiment of the present invention, the latex is at least one of natural latex, styrene-butadiene latex, and nitrile latex. Those skilled in the art can select a suitable latex according to the actual situation. The weight ratio of the dry weight of basic silica white in the modified basic silica white slurry to the dry rubber in the latex is 1:1-10, preferably 1:2-6. Those skilled in the art can select a suitable weight ratio of the modified basic silica white slurry to the latex according to the actual situation.

[0030] A fourth object of the present invention is to provide a method for preparing the masterbatch described in the third object of the present invention, and the method includes:

[0031] Mix the latex and the modified alkaline silica white slurry evenly and then perform a drying treatment to obtain the masterbatch.

[0032] The present invention can specifically adopt the following technical solutions:

[0033] Add the modified alkaline silica white slurry and the latex into a high-speed disperser for mixing to obtain a modified alkaline silica white-filled latex. The rotation speed of the high-speed disperser is controlled at 2000 - 5000 rpm to fully mix the alkaline silica white and the latex. Dry the alkaline silica white-filled latex to prepare the masterbatch.

[0034] In a preferred embodiment of the present invention, the drying treatment is performed using a spray dryer, specifically it can be a pressure spray dryer, a centrifugal spray dryer or other drying equipment, preferably a spray dryer. More preferably, the inlet temperature of the spray dryer is 190 - 220 °C, and the outlet temperature of the spray dryer is 60 - 100 °C. Those skilled in the art can select appropriate inlet and outlet temperatures according to actual needs.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. The present invention adopts a grinding treatment, making the alkaline silica white have a smaller particle size, thereby being able to provide more reactive sites and ultimately achieving a better modification effect.

[0037] 2. The present invention hydrolyzes the silane coupling agent under acidic conditions first, reducing the occurrence of self-condensation reaction of the silane coupling agent, improving the utilization rate of the silane coupling agent, and enabling the alkaline silica white to achieve a better modification effect. In addition, by hydrolyzing the silane coupling agent under acidic conditions, then modifying the alkaline silica white within a preset particle size range, and combining with the use of an activator, the technical problem of poor dispersibility of the alkaline silica white as a filler in the material matrix is jointly solved.

[0038] 3. The modified alkaline silica white of the present invention can improve the stability of the latex and is not prone to emulsion breaking during the compounding process.

[0039] 4. The modification method of the present invention has simple equipment requirements, a simple process, is easy to reproduce and can be put into industrial production. Specific embodiments

[0040] The present invention will be specifically described below in conjunction with specific embodiments. It is necessary to point out here that the following embodiments are only used for further illustration of the present invention and should not be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

[0041] Preparation of basic silica white cake:

[0042] First step, mix water glass solution and CO2 for precipitation reaction. Specifically, add the water glass solution into the carbonization reactor, heat it with steam to 80 °C, then introduce CO2 gas with a flow rate controlled at 100 ml / min. When the pH drops to 10, stir and mix for 30 min, and keep the pressure for aging for 60 min;

[0043] Second step, pump the aged slurry into a plate and frame filter press, and wash it with clear water until the conductivity is 300 S / m to obtain a basic silica white cake with a solid content of 40 wt%.

[0044] Preparation of acidic silica white cake:

[0045] First step, mix water glass solution and CO2 for precipitation reaction. Specifically, add the water glass solution into the carbonization reactor, heat it with steam to 80 °C, then introduce CO2 gas with a flow rate controlled at 100 ml / min. When the pH drops to 10, stir and mix for 30 min, and keep the pressure for aging for 60 min;

[0046] Second step, add sulfuric acid to the aged slurry to adjust the pH to 6, then pump it into a plate and frame filter press, and wash it with clear water until the conductivity is 300 S / m to obtain an acidic silica white cake with a solid content of 40 wt%.

[0047] In the present invention, the raw materials used in the examples and comparative examples are all conventional commercially available raw materials.

[0048] Example 1

[0049] S1. Add 5 g of γ-mercaptopropyltrimethoxysilane and 0.5 g of fatty alcohol polyoxyethylene ether to 16.5 g of water, mix evenly, add dilute sulfuric acid to control its pH value to 1 to obtain 22.5 g of acidic aqueous solution, and hydrolyze for 1 h to obtain a hydrolysis solution of γ-mercaptopropyltrimethoxysilane.

[0050] S2. Add 12.5 kg of basic silica white cake with a solid content of 40 wt%, 37.5 kg of water and 0.5 g of sodium aluminate into a colloid mill for pulping to obtain a basic silica white slurry with a solid content of 10 wt%.

[0051] S3. Add the alkaline silica white slurry to a ball mill and a sand mill for grinding, and classify it with a classifier wheel to control the particle size at 0.1 μm, obtaining the ground alkaline silica white slurry.

[0052] S4. Add the γ-mercaptopropyltrimethoxysilane hydrolysis solution to the slurry, heat it to 40 °C in a microchannel reactor for grafting reaction, and the reaction time is 0.1 h, obtaining the modified alkaline silica white slurry.

[0053] S5. Add the modified alkaline silica white slurry and 100 kg of emulsion polymerized styrene-butadiene latex (solid content 50 wt%) to a high-speed disperser for mixing for 0.5 h, obtaining a uniformly mixed and non-demulsified modified alkaline silica white latex slurry.

[0054] S6. Spray-dry the modified alkaline silica white latex slurry, with an inlet temperature of 190 °C and an outlet temperature of 60 °C, obtaining the modified alkaline silica white filled masterbatch.

[0055] Example 2

[0056] S1. Add 500 g of γ-mercaptopropyltriethoxysilane and 1 kg of alkylphenol polyoxyethylene ether to 3 kg of water, mix evenly, add nitric acid to control its pH value at 6, obtaining 4.6 kg of acidic aqueous solution, with a hydrolysis time of 20 h, obtaining the γ-mercaptopropyltriethoxysilane hydrolysis solution.

[0057] S2. Add 15.63 kg of alkaline silica white filter cake with a solid content of 40 wt%, 5.21 kg of water and 3.1 g of sodium hexametaphosphate to a colloid mill for pulping, obtaining an alkaline silica white slurry with a solid content of 30 wt%.

[0058] S3. Add the alkaline silica white slurry to a ball mill and a sand mill for grinding, and classify it with a classifier wheel to control the particle size at 2 μm, obtaining the ground alkaline silica white slurry.

[0059] S4. Add the γ-mercaptopropyltriethoxysilane hydrolysis solution to the slurry, heat it to 95 °C in a microchannel reactor for grafting reaction, and the reaction time is 3 h, obtaining the modified alkaline silica white slurry.

[0060] S5. Add the modified alkaline silica white slurry and 12.504 kg of nitrile rubber latex (solid content 50 wt%) to a high-speed disperser for mixing for 2 h, obtaining a uniformly mixed and non-demulsified modified alkaline silica white latex slurry.

[0061] S6. Spray-dry the modified alkaline silica white latex slurry, with an inlet temperature of 220 °C and an outlet temperature of 100 °C, obtaining the modified alkaline silica white filled masterbatch.

[0062] Example 3

[0063] S1. Add 50 g of γ-(methacryloyloxy)propyltrimethoxysilane and 25 g of fatty acid polyoxyethylene ester to 125 g of water, mix evenly, add hydrochloric acid to control the pH value to 2, obtain 205 g of acidic aqueous solution, and hydrolyze for 3 h to obtain the hydrolysis solution of γ-(methacryloyloxy)propyltrimethoxysilane.

[0064] S2. Add 12.5 kg of alkaline silica white filter cake with a solid content of 40 wt%, 20.833 kg of water and 1 g of sodium hydroxide to a colloid mill for pulping to obtain an alkaline silica white slurry with a solid content of 15 wt%.

[0065] S3. Add the alkaline silica white slurry to a ball mill and a sand mill for grinding treatment, and classify with a classifier wheel to control the particle size to 0.3 μm to obtain the ground alkaline silica white slurry.

[0066] S4. Add the hydrolysis solution of γ-(methacryloyloxy)propyltrimethoxysilane to the slurry, heat up to 50 °C in a microchannel reactor for grafting reaction, and the reaction time is 0.5 h to obtain the modified alkaline silica white slurry.

[0067] S5. Add the modified alkaline silica white slurry and 50 kg of natural rubber latex (solid content 50 wt%) to a high-speed disperser for mixing for 1 h to obtain a uniformly mixed and non-demulsified modified alkaline silica white latex slurry.

[0068] S6. Spray-dry the modified alkaline silica white latex slurry, with the inlet temperature of 195 °C and the outlet temperature of 65 °C to obtain the modified alkaline silica white filled masterbatch.

[0069] Example 4

[0070] S1. Add 100 g of γ-aminopropyltriethoxysilane and 70 g of polyoxyethylene alkylamine to 333 g of water, mix evenly, add hydrochloric acid to control the pH value to 3, obtain 510 g of acidic aqueous solution, and hydrolyze for 7 h to obtain the hydrolysis solution of γ-aminopropyltriethoxysilane.

[0071] S2. Add 12.5 kg of alkaline silica white filter cake with a solid content of 40 wt%, 16.911 kg of water and 1.5 g of sodium hydroxide to a colloid mill for pulping to obtain an alkaline silica white slurry with a solid content of 17 wt%.

[0072] S3. Add the alkaline silica white slurry to a ball mill and a sand mill for grinding treatment, and classify with a classifier wheel to control the particle size to 0.5 μm to obtain the ground alkaline silica white slurry.

[0073] S4. Add the hydrolyzate of γ-aminopropyltriethoxysilane to the slurry, heat it to 60 °C in a microchannel reactor for grafting reaction for 1 h to obtain a modified alkaline silica white slurry.

[0074] S5. Add the modified alkaline silica white slurry and 33.332 kg of emulsion-polymerized styrene-butadiene latex (solid content 50 wt%) to a high-speed disperser and mix for 0.5 h to obtain a uniformly mixed and non-demulsified modified alkaline silica white latex slurry.

[0075] S6. Spray-dry the modified alkaline silica white latex slurry, with an inlet temperature of 200 °C and an outlet temperature of 70 °C, to obtain a modified alkaline silica white filled masterbatch.

[0076] Example 5

[0077] S1. Add 150 g of bis-(γ-triethoxysilylpropyl)tetrasulfide and 150 g of polyoxyethylene alkylamide to 375 g of water, mix evenly, add nitric acid to control its pH value to 4 to obtain 700 g of an acidic aqueous solution, and hydrolyze for 10 h to obtain the hydrolyzate of bis-(γ-triethoxysilylpropyl)tetrasulfide.

[0078] S2. Add 12.5 kg of an alkaline silica white filter cake with a solid content of 40 wt%, 12.5 kg of water and 2 g of potassium hydroxide to a colloid mill for pulping to obtain an alkaline silica white slurry with a solid content of 20 wt%.

[0079] S3. Grind the alkaline silica white slurry in a ball mill and a sand mill, and classify it with a classifier wheel to control the particle size to 1 μm to obtain a ground alkaline silica white slurry.

[0080] S4. Add the hydrolyzate of bis-(γ-triethoxysilylpropyl)tetrasulfide to the slurry, heat it to 70 °C in a microchannel reactor for grafting reaction for 1.5 h to obtain a modified alkaline silica white slurry.

[0081] S5. Add the modified alkaline silica white slurry and 25 kg of nitrile rubber latex (solid content 50 wt%) to a high-speed disperser and mix for 1.5 h to obtain a uniformly mixed and non-demulsified modified alkaline silica white latex slurry.

[0082] S6. Spray-dry the modified alkaline silica white latex slurry, with an inlet temperature of 205 °C and an outlet temperature of 75 °C, to obtain a modified alkaline silica white filled masterbatch.

[0083] Example 6

[0084] S1. Add 200 g of bis-(γ-triethoxysilylpropyl) disulfide and 300 g of fatty alcohol polyoxyethylene ether to 400 g of water, mix evenly, add sulfuric acid to control the pH value to 5, obtain 920 g of acidic aqueous solution, and carry out hydrolysis for 15 h to obtain the hydrolysis solution of bis-(γ-triethoxysilylpropyl) disulfide.

[0085] S2. Add 12.5 kg of alkaline silica white filter cake with a solid content of 40 wt%, 7.5 kg of water and 1 g of sodium aluminate into a colloid mill for pulping to obtain an alkaline silica white slurry with a solid content of 25 wt%.

[0086] S3. Add the alkaline silica white slurry into a ball mill and a sand mill for grinding treatment, and classify it with a classification wheel to control the particle size to 1.5 μm to obtain the ground alkaline silica white slurry.

[0087] S4. Add the hydrolysis solution of bis-(γ-triethoxysilylpropyl) disulfide to the slurry, heat it to 80 °C in a microchannel reactor for grafting reaction, and the reaction time is 2.5 h to obtain the modified alkaline silica white slurry.

[0088] S5. Add the modified alkaline silica white slurry and 20 kg of natural rubber latex (solid content 50 wt%) into a high-speed disperser for mixing for 1 h to obtain a uniformly mixed and non-demulsified modified alkaline silica white latex slurry.

[0089] S6. Carry out spray drying treatment on the above slurry, with the inlet temperature of 210 °C and the outlet temperature of 80 °C to obtain the modified alkaline silica white filled masterbatch.

[0090] Comparative Example 1

[0091] S1. Add 5 g of γ-mercaptopropyltrimethoxysilane and 0.5 g of fatty alcohol polyoxyethylene ether to 16.5 g of water, mix evenly, add dilute sulfuric acid to control the pH value to 1, obtain 22.5 g of acidic aqueous solution, and carry out hydrolysis for 1 h to obtain the hydrolysis solution of γ-mercaptopropyltrimethoxysilane.

[0092] S2. Add 12.5 kg of alkaline silica white filter cake with a solid content of 40 wt%, 37.5 kg of water and 0.5 g of sodium aluminate into a colloid mill for pulping to obtain an alkaline silica white slurry with a solid content of 10 wt%.

[0093] S3. Add the hydrolysis solution of γ-mercaptopropyltrimethoxysilane to the slurry, heat it to 40 °C in a microchannel reactor for grafting reaction, and the reaction time is 0.1 h to obtain the modified alkaline silica white slurry.

[0094] S4. Add the modified alkaline silica white slurry and 100 kg of emulsion polymerized styrene butadiene rubber latex (solid content 50 wt%) to a high-speed disperser and mix for 0.5 h to obtain a modified alkaline silica white rubber latex slurry.

[0095] S5. Spray-dry the modified alkaline silica white rubber latex slurry at an inlet temperature of 190 °C and an outlet temperature of 60 °C to obtain a modified alkaline silica white filled masterbatch.

[0096] Comparative Example 2

[0097] S1. Add 50 g of γ-(methacryloyloxy)propyltrimethoxysilane and 25 g of fatty acid polyoxyethylene ester to 125 g of water, mix evenly, add hydrochloric acid to control the pH value to 2, obtain 205 g of acidic aqueous solution, and hydrolyze for 3 h to obtain a hydrolyzate of γ-(methacryloyloxy)propyltrimethoxysilane.

[0098] S2. Add 12.5 kg of acidic silica white filter cake with a solid content of 40 wt%, 20.833 kg of water and 1 g of sodium hydroxide to a colloid mill for pulping to obtain an acidic silica white slurry with a solid content of 15 wt%.

[0099] S3. Grind the acidic silica white slurry by adding it to a ball mill and a sand mill, and classify it with a classifier wheel to control the particle size to 0.3 μm to obtain a ground acidic silica white slurry.

[0100] S4. Add the hydrolyzate of γ-(methacryloyloxy)propyltrimethoxysilane to the above slurry, heat it to 50 °C in a microchannel reactor for grafting reaction, and the reaction time is 0.5 h to obtain a modified acidic silica white slurry.

[0101] S5. Add the modified acidic silica white slurry and 50 kg of natural rubber latex (solid content 50 wt%) to a high-speed disperser and mix for 1 h to obtain a modified acidic silica white rubber latex slurry with a little flocculant.

[0102] S6. Spray-dry the modified acidic silica white rubber latex slurry at an inlet temperature of 195 °C and an outlet temperature of 65 °C to obtain a modified acidic silica white filled masterbatch.

[0103] Comparative Example 3

[0104] S1. Add 500 g of γ-mercaptopropyltriethoxysilane and 1 kg of alkylphenol polyoxyethylene ether to 3 kg of water, mix evenly, add nitric acid to control the pH value to 6, obtain 4.6 kg of acidic aqueous solution, and hydrolyze for 20 h to obtain a hydrolyzate of γ-mercaptopropyltriethoxysilane.

[0105] S2. After adding 15.63 kg of alkaline silica white cake with a solid content of 40 wt% and 5.21 kg of water into a colloid mill for pulping, an alkaline silica white slurry with a solid content of 30 wt% is obtained;

[0106] S3. Add the alkaline silica white slurry into a ball mill and a sand mill for grinding, and classify it with a classifier wheel to control the particle size to be 2 μm, obtaining the ground alkaline silica white slurry.

[0107] S4. Add the hydrolysis solution of γ-mercaptopropyltriethoxysilane to the slurry, heat it to 95 °C in a microchannel reactor for grafting reaction, and the reaction time is 3 h, obtaining the modified alkaline silica white slurry.

[0108] S5. Add the modified alkaline silica white slurry and 12.504 kg of nitrile latex (solid content 50 wt%) into a high-speed disperser for mixing for 2 h, obtaining a uniformly mixed and non-demulsified modified alkaline silica white latex slurry.

[0109] S6. Perform spray drying treatment on the modified alkaline silica white latex slurry, with the inlet temperature being 220 °C and the outlet temperature being 100 °C, obtaining the modified alkaline silica white filled masterbatch.

[0110] The mechanical properties, grinding properties, and dispersion properties of the masterbatches of Examples 1 to 6 and Comparative Examples 1 to 3 are tested. Among them, Mooney viscosity is an important index to measure the processing performance of rubber, and the dispersion of fillers has a significant impact on the processing performance of rubber. The better the dispersion of fillers in rubber, the lower the Mooney viscosity of rubber, and the better the processing performance. The test methods for mechanical properties, grinding properties, and dispersion properties are shown in Table 1;

[0111] Table 1 Test methods for Examples 1 to 6 and Comparative Examples 1 to 3

[0112] Physical tests Standards / Conditions Mechanical tests GB / T528-2009 DIN abrasion test DIN 53516 Mooney viscosity test GB / T1232

[0113] The test results of Examples 1 to 6 and Comparative Examples 1 to 3 are shown in Table 2.

[0114] Table 2 Test results of mechanical properties, grinding properties, and dispersion properties of Examples 1 to 6 and Comparative Examples 1 to 3

[0115]

[0116] It can be seen from Table 2 that the mechanical properties, wear resistance, and dispersion of fillers of the rubber composites in Examples 1 to 6 are well reflected.

[0117] Compared with Example 1, the alkaline silica used in Comparative Example 1 is unground and used as a filler. From its mechanical properties, wear resistance and Mooney viscosity, it can be seen that the dispersion, reinforcement performance and wear resistance of the unground alkaline silica in the rubber matrix are all worse than those of Example 1, which proves the advantage of grinding the alkaline silica.

[0118] Compared with Example 3, the acidic silica used in Comparative Example 2 is used as a filler. From its mechanical properties, wear resistance and Mooney viscosity, it can be seen that the mechanical properties, wear resistance and dispersion of the silica in Comparative Example 2 are all worse than those of Example 3. This is because the addition of the acidic silica slurry to the latex easily causes demulsification and flocculation, resulting in poor dispersion, which in turn affects its mechanical properties and wear resistance.

[0119] Compared with Example 2, Comparative Example 3 did not add an activator to treat the silica slurry, resulting in slightly worse mechanical properties, wear resistance and filler dispersion performance than Example 2. This is because the silica slurry is relatively viscous, resulting in poor dispersion during mixing with the latex, which in turn affects its mechanical properties and wear resistance.

Claims

1. A method for modifying alkaline precipitated silica, characterized in that: The method comprises (1) adding a surfactant and a silane coupling agent into water, hydrolyzing, and adjusting the pH to 1-6 to obtain a hydrolyzed solution of the silane coupling agent; (2) pulping and grinding the basic silica white, water and an activator to obtain a basic silica white slurry; (3) mixing the hydrolyzed solution of the silane coupling agent and the basic silica white slurry, heating up for reaction to obtain modified basic silica white.

2. The method according to claim 1, wherein: the silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, bis-(γ-triethoxysilylpropyl)tetrasulfide, bis-(γ-triethoxysilylpropyl)disulfide, preferably at least one of γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, bis-(γ-triethoxysilylpropyl)tetrasulfide; and / or the surfactant is at least one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, preferably at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester; and / or the activator is a basic activator, and the basic activator is preferably at least one of sodium aluminate, sodium hexametaphosphate, sodium hydroxide, potassium hydroxide, more preferably at least one of sodium aluminate, sodium hexametaphosphate.

3. The method according to claim 1, wherein: in step (1), the weight ratio of the water, the surfactant, and the silane coupling agent is 2-6: 0.1-2:1, preferably 2.2-4:0.5-1:1; and / or in step (2), the weight ratio of the water, the activator, and the dry weight of the basic silica white is 0.83-7.5:0.0001-0.0005:1, preferably 1.5-5:0.0002-0.0004:1; and / or in step (3), the weight ratio of the silane coupling agent in the hydrolyzed solution of the silane coupling agent and the dry weight of the basic silica white in the basic silica white slurry is 0.1-8:100, preferably 0.5-3:

100.

4. The method according to claim 1, characterized in that: In step (2) the particle size of the basic silica white slurry is 0.1-2 μm, preferably 0.5-1 μm; and / or the solid content of the basic silica white slurry is 10-30 wt%, preferably 14-25 wt%.

5. The method according to claim 1, wherein: in step (1), the hydrolysis time is 1-20 h, preferably 8-17 h; and / or in step (3), the reaction temperature is 40-95 °C, preferably 45-70 °C; and / or in step (3), the reaction time is 0.1-3 h, preferably 1-2.5 h.

6. A modified basic silica white prepared by the method according to any one of claims 1-5.

7. A masterbatch comprising the modified basic silica white according to claim 6, wherein: the masterbatch is prepared by uniformly mixing latex and a modified basic silica white slurry and then performing a drying treatment.

8. The masterbatch according to claim 7, wherein: The latex is at least one of natural latex, styrene-butadiene latex, and nitrile latex.

9. The masterbatch according to claim 7, wherein: In the modified alkaline silica slurry, the weight ratio of the dry weight of the alkaline silica to the dry rubber in the latex is 1:1 to 10, preferably 1:2 to 6.

10. A method for preparing the masterbatch according to any one of claims 7 to 9, characterized in that The method includes: Mixing the latex and the modified alkaline silica slurry evenly and then performing a drying treatment to obtain the masterbatch; Preferably, the drying treatment is carried out using a spray dryer; More preferably, the inlet temperature of the spray dryer is 190 to 220 °C, and the outlet temperature of the spray dryer is 60 to 100 °C.

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