The effect of gas-phase matting powder depends to a large extent on the dispersion strength, which at least requires the use of a high-speed disperser. To achieve the best dispersion effect, rotor stator dispersion or ball mill, three-roller dispersion, etc. can be used. The best choice of dispersion method and dispersion equipment depends on the consistency of the system. It is recommended to first disperse all fumed silica with part of the liquid or part of the formula raw materials, and then add the remaining liquid and other formula raw materials to adjust the content of fumed silica to Recipe requires proportions.
Selection of silica:
1. Consider the physical and chemical properties of silica, such as particle size distribution and average particle size.
2. Choose appropriate products according to different resin properties, solvent types, and system viscosity.
3. Reasonably select precipitated silica and fumed silica. The gas phase method is characterized by good transparency, both haze and blackness, and good color development. It is mostly used in mid-to-high-end products. The precipitation method is characterized by high extinction efficiency, limited transparency, insufficient color development, and comprehensive blackness and haze efficiency of about 70% of the gas phase method. It is mostly used for mid- to low-end products.
Evaluation methods for silica products:
1. Evaluate the blackness of the coating and its transparency;
2. It is better to observe the non-reflection with the naked eye (or use a gloss meter), and evaluate the haze or matting properties
3. Repeatedly observe whether the coating turns white and evaluate the scratch resistance;
4 . Let the prepared coating agent stand still for a period of time. If there is no hard sediment, evaluate the suspension property.
