Basic knowledge of organic pigments-the decisive role of particle size

Particle size has a significant impact on the performance of organic pigments. The specific relationship is as follows:

1. Transparency vs. hiding power

Small particle size → high transparency (less light scattering, more transmission)

Large particle size → strong hiding power (more light scattering, enhanced reflection)

2. Color strength (tinting strength)

Small particle size → high color strength (more particles per unit mass, larger color rendering area)

Large particle size → low color strength (few particles, low color rendering efficiency)

3. Viscosity (affected by the dispersion system)

Small particle size → high viscosity (large specific surface area, strong interaction between particles)

Large particle size → low viscosity (reduced friction between particles, good fluidity)

4. Specific surface area

Small particle size → high specific surface area (smaller particles, larger total surface area at the same mass)

Large particle size → low specific surface area (coarse particles, small total surface area)

5. Addition amount (to achieve the same coloring effect)

Small particle size → Low addition (high color strength, small amount can be used to develop color)

Large particle size → high addition (low coloring efficiency, more amount is needed)

6. Fastness (light resistance/weather resistance/migration resistance)

Small particle size → lower fastness (high specific surface area is susceptible to environmental erosion and easy to migrate)

Large particle size → higher fastness (stable structure, stronger weather resistance)

In practical applications, organic pigments with appropriate particle size need to be selected according to the needs (such as transparent ink vs. high hiding paint).