The amount of precipitated silica added to coatings needs to be determined based on specific application requirements and coating systems. Here are some common ranges and methods for determining the amount of additives:

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1. As a matting agent
Precipitation method silica is commonly used as a matting agent in coatings, with an addition amount generally between 0.5% and 3%. The specific amount of addition depends on the required extinction effect and the type of coating. For example:
For coatings that require high extinction effects, the addition amount may be close to 3%.
For coatings that only require a slight extinction effect, the addition amount may be around 0.5%.

2. As a rheological control agent or anti settling agent
Precipitation method silica can also be used to improve the rheological properties of coatings and prevent pigment precipitation. In this case, the addition amount is usually between * * 0.4% and 2% * *. For example:
In ordinary coatings, the addition amount may be between 0.4% and 0.8%.
In special coatings such as zinc rich paint, the addition amount may need to be increased to 2%.

3. As a filler
When using precipitated silica as a filler, the addition amount usually does not exceed 2%. The specific amount of addition depends on the formula and performance requirements of the coating.

4. Method for determining the amount of addition
Experimental verification: Determining the optimal addition amount through experiments is a common method. Coating samples with different addition amounts can be prepared to test their extinction effect, rheological properties, and stability, in order to select the most suitable addition amount.
Adjust according to the type of coating: Different coating systems (such as solvent based coatings, water-based coatings, powder coatings) have different requirements for the amount of precipitated silica added. For example, water-based coatings may require lower addition amounts, while powder coatings may require higher addition amounts.
Considering dispersibility: The dispersibility of precipitated silica has a significant impact on its properties. If the dispersion is uneven, it may be necessary to adjust the addition amount or optimize the dispersion process.

5. Precautions
Excessive addition may lead to strong thixotropy of the coating, affecting dispersion efficiency.
If the addition amount is too low, it may not achieve the expected extinction or rheological control effect.
In summary, the amount of precipitated silica added to coatings needs to be adjusted according to specific application requirements, coating types, and performance requirements, usually between 0.4% and 3%.