Preparation method of hydrophobic white carbon black with controllable particle size and core-shell structure

Abstract

The invention belongs to the field of white carbon black, and discloses a preparation method of hydrophobic white carbon black with controllable particle size and a core-shell structure. The preparation method disclosed by the invention comprises the following steps of: preparing a sodium silicate solution, adding an acid catalyst into the sodium silicate solution, adjusting the pH value of an obtained system to be 10 to 10.5, reacting for 20-35 minutes, continuously adding the acidic catalyst, regulating the pH value of the system to 3.5-4.6, reacting for 40-60 minutes, adding a hydrophobic modifier, adding a cosolvent, reacting for 1-12 hours at 50-80 DEG C, and carrying out filter pressing, washing and drying to obtain the hydrophobic white carbon black with the core-shell structure. According to the preparation method, the number of hydroxyl groups on the surface of the white carbon black is reduced through a co-condensation method of the white carbon black and the hydrophobic modifier, and aggregation of the white carbon black in the drying process is reduced, so that the preparation of the white carbon black with controllable particle size, good hydrophobicity, high specificsurface area and high oil absorption is realized.

Description

technical field [0001] The invention relates to the field of white carbon black, in particular to a method for preparing hydrophobic white carbon black with a controllable particle size and a core-shell structure. Background technique [0002] Because silica can play a reinforcing role similar to carbon black in rubber and its color is white, it is called white carbon black. At present, there are two main methods of preparing white carbon black: precipitation method and gas phase method. Due to the complex production process, high cost and low output of gas phase method, all domestic production methods of white carbon black are still dominated by precipitation method. [0003] Due to its stable chemical properties, green and non-toxic, high temperature resistance, and high specific surface area, silica is widely used in rubber industry, coatings, paints, defoamers, and engineering plastics as fillers and reinforcing agents. . Silica is generally used as an additive in poly...

AI Technical Summary

Problems solved by technology

Silica is generally used as an additive in polymer materials, but there are the following problems in the use of silica: (1) The compatibility between silica and polymer materials is poor, and it is easy to appear in the blending process. Separation; (2) The surface of silica contains a large number of silanol groups, resulting in high surface energy, and the silica is easy to aggregate to form larger silica particles, resulting in the formation of silica in polymer materials. Stress concentration, thereby reducing the performance and service life of the material itself; (3) The particle size of the silica prepared by the precipitation method is too large, generally reaching more than 10 μm; (4) A large number of hydroxyl groups on the surface of the silica will not only affect Its compatibility with rubber will also increase the vulcanization time of rubber and reduce production efficiency

However, these two methods have the disadvantages of relatively complicated preparation process, complicated post-processing, and easy to cause environmental pollution, and the particle size of the modified silica has not changed significantly, still reaching tens of microns to tens of microns

At present, the preparation method of small particle size white carbon black is mainly prepared by gas phase method, but the technical threshold of gas phase method is relatively high, and the domestic market is basically monopolized by foreign-funded enterprises

Most domestic enterprises prepare silica with small particle size through physical grinding. Physical grinding is generally divided into wet grinding and dry grinding. Wet grinding needs to add a dispersant to the white carbon black. During the drying process, the white Carbon black will still aggregate and introduce impurities; the main disadvantage of dry grinding modification is that it is difficult to uniformly treat the surface of silica, and it will consume a large amount of modifiers, and the equipment used is complicated and expensive, which will greatly reduce Increase the production cost of the enterprise

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