Method for preparing super fine hydrophobic silicon dioxide

Abstract

A process for preparing the superfine hydrophobic SiO2 includes such steps as proportionally mixing ethyl n-silicate, ammonium chloride, de-ionized water, absolute alcohol, hydrochloric acid, ammonia water, gamma-aminopropyltriethoxy silane and ethanediol, preparing sol, preparing gel, baking, grinding, sieving, calcining, cooling, hydrophobic modifying, reaction, filter, baking and examining.

Description

Technical field: [0001] The invention relates to a method for preparing ultrafine hydrophobic silicon dioxide, which belongs to the technical field of methods for preparing inorganic compounds of non-metallic composite materials. Background technique: [0002] Inorganic compound silica is an inorganic additive with excellent performance and wide application. It is commonly known as white carbon black. Thermal, wear-resistant and welding properties, are widely used in rubber, plastics, coatings, adhesives, sealants, optical fiber materials, polymer materials, modern medicine, bioengineering, optics and other fields. [0003] At present, there are many methods for preparing modified silica, such as gas phase method, precipitation method, gravity sedimentation method, etc., and the modified form is modified by adding thiol silane coupling agent, such as 3-thiol group Methoxypropyl silane method, adding titanate method, dry method, wet method, heat treatment method, chemical tr...

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Problems solved by technology

[0004] For example: the gas phase method uses silicon halide as the raw material to produce silicon tetrachloride by hydrolysis in an oxyhydrogen flame. It hydrolyzes silicon dioxide gas at a high temperature of 1200°C and then condenses it. The gas phase method has a small concentration of substances and produces The particle aggregation is less, the preparation and roasting temperature is high, the energy consumption in the production process is large, the cost is high, and the pollution is large

[0005] For example: the precipitation method uses basic silicate as the raw material and uses water or organic solvent as the reaction medium. The precipitation method also has various forms: preparing silica with high dispersion performance in organic solvent, acidifying agent and silicate Reaction, precipitation, separation, drying to prepare silica, alkali metal silicate and inorganic acid mixed preparation, water glass carbonation preparation, spray granulation preparation, due to the difference in reaction medium, reaction ratio and process conditions, the properties of the obtained product Very different, difficult to control

[0006] For example: the gravity sedimentation method is to make the particles in the suspension settle, diffuse, crystallize and obtain silica particles under the gravitational field, but it is difficult to control the orderly arrangement of the crystal particles of silica, and the preparation time is long

[0007] There are also many forms of silica modification, but in the modification process, there are also many shortcomings, some do not meet the needs of the product, some have a long modification period, and some have unstable chemical properties after modification.

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