Surface Modifiers, Processes and Equipment For Silicon micropowder
Silicon micro powder is a silica powder material made of natural quartz ore, fused silica, etc. as raw materials, which is processed by grinding, precision classification, and impurity removal. It has high insulation, high thermal conductivity, high thermal stability, Acid and alkali resistance, wear resistance, low thermal expansion coefficient, low dielectric constant and other characteristics, are widely used in the copper clad laminate industry, epoxy plastic packaging industry, electrical insulation material industry and adhesive industry.
In order to improve the interface between silicon micropowder and organic polymer materials and improve its application performance, it is generally necessary to modify the surface of silicon micropowder. The key to the surface modification of silica micropowder is how to make the modifier uniformly disperse on the particle surface, and at the same time ensure the chemical bonding conditions between the modifier and the particle surface. Ultra-fine silicon powder has a large specific surface area, and how to make the modifier evenly dispersed on the particle surface is a difficult problem that plagues silicon powder manufacturers.
- Surface modifier
Silane coupling agent is the most commonly used modifier for surface modification of silicon micropowder. It can convert the hydrophilicity of silicon micropowder into an organic hydrophilic surface, and can also improve the wettability of organic polymer materials to its powder. Make the silicon micropowder and the organic polymer material achieve a firm covalent bond interface.
However, the application effect of the silane coupling agent is related to the selected type, dosage, hydrolysis situation, substrate characteristics, application occasions, methods and conditions of organic polymer materials. Therefore, in order to use a silane coupling agent well, it is necessary to carefully study its structure, properties and the mechanism of its interaction with silicon micropowder, so as to correctly select and use a good silane coupling agent.
- Surface modification process
Because the dry process is relatively simple and the production cost is relatively low, at present, the surface modification of silicon micropowder in China basically adopts the dry process. However, the specific surface area of the ultra-fine silicon powder is relatively large, and the mechanical dispersion of the equipment alone cannot make the treatment agent evenly dispersed on the surface of the particles, so the effect of dry modification is relatively poor.
Wet modification is carried out under liquid phase conditions. The modifier can disperse the particle surface relatively uniformly. Generally speaking, the modification effect is good. However, the wet modification process is complicated, requires drying and depolymerization processes, and the production cost is relatively high. high, but the wet modification effect is better.
- Surface modification equipment
The selection of surface modification equipment is a crucial part of the surface modification of silicon micropowder. When selecting surface modification equipment, the following requirements should be considered:
At present, there are many surface modification equipments in China, but some surface modification equipments are not manufactured in accordance with the mechanism and process requirements of surface modification of silicon powder, resulting in poor surface modification effect. Therefore, it is necessary to modify the purchased modified equipment. Only after the equipment is transformed and matched can it achieve better results.
Finally, it is stated that in order to do a good job in the surface modification of silica micropowder, it is necessary to carefully understand the structure and properties of the surface modifier based on the mechanism of surface modification, and at the same time consider the substrate and main formula of downstream organic polymer products. And technical requirements, after comprehensive consideration, select a reasonable modifier, and on this basis, determine the surface modification process and equipment.
