According to the coloring objects and environmental requirements, colorants are mainly divided into two types: lightfast and non-lightfast. Generally, when the system is not compatible for internal use, it is based on the principle of low cost to achieve color requirements, and does not require light fastness. For external use, the following factors must be considered:
a. Light and weather resistance; b. Chemical resistance (mainly acid and alkali resistance); c. Compatibility with the application system; d. Coloring strength, hiding power and color development; Inter-matching f. storage stability of color paste;
In general, the color retention of external coatings is quite strict, so when choosing color pastes, special attention should be paid to the light resistance and weather resistance and acid and alkali resistance of the color paste. Under the premise of good compatibility, tinting strength, hiding power, color development and storage stability, the mutual matching of colorants is also crucial. As far as possible, choose single-color colorants with superior performance such as light and weather resistance, but in fact, they are often composite colors, so follow the performance of inorganic and inorganic, organic and organic, or light and weather resistance. In this way, the outdoor color retention can be ensured, and the fading caused by the obvious difference in the weather resistance of the color paste can be avoided for a long time. or coating defects such as uneven color and blooming.