What are the main problems of paint anti-sinking？

The main issues related to sedimentation in coatings include the following:

1. Sedimentation of Pigments and Fillers

Issue: Coatings often contain pigments, fillers, and other solid particles, which can settle over time, reducing the uniformity and stability of the coating, affecting its application and performance.

Cause: Mismatch between the density of the particles and the viscosity of the base material, or a lack of effective dispersants and thickeners in the formulation.

Solution:

Use dispersants to reduce the aggregation force between particles and keep them evenly distributed.

Add suitable thickeners or rheological modifiers to increase the coating's viscosity and slow down particle sedimentation.

2. Uneven Coating Viscosity or "Hard Sedimentation"

Issue: Some particles in the coating settle faster, causing uneven viscosity and leading to issues like stratification or inconsistent coating thickness.

Cause: Certain particles, such as pigments and fillers, may not be properly dispersed, or the type or concentration of thickeners used may not be effective enough to prevent sedimentation.

Solution:

Use more efficient dispersants and rheological modifiers, particularly those that enhance the suspension stability of particles.

Choose appropriate polymeric thickeners, such as acrylics, polyurethanes, etc., that have good suspending capabilities.

3. Coating Rheology (Shear-Thinning/Shear-Thickening)

Issue: Improper rheological properties can lead to sedimentation in coatings during storage or application.

Cause: If the coating viscosity is too low, particles will settle quickly; if the viscosity is too high, it will affect the flowability and application.

Solution:

Use the right rheological modifiers to ensure that the coating has high viscosity at low shear rates and good flowability at high shear rates.

Choose non-silicone dispersants or thickeners to maintain balance between preventing sedimentation and ensuring good application properties.

4. Temperature Fluctuations Causing Sedimentation

Issue: Temperature changes can affect the viscosity of the coating, leading to sedimentation problems, especially in high-temperature environments where some thickeners may lose their effectiveness.

Cause: Some thickeners are sensitive to temperature changes and may lose their effectiveness at either high or low temperatures, resulting in sedimentation.

Solution:

Choose temperature-stable thickeners, such as polyurethane-based or high-temperature-resistant silica thickeners.

Conduct thermal stability tests to ensure that the coating maintains stability under different temperature conditions.

5. Uneven or Incomplete Dispersion

Issue: Pigments, fillers, and other solid particles are not fully dispersed, leading to particle aggregation and sedimentation.

Cause: Inadequate choice of dispersants or improper dispersion processes can cause solid particles to agglomerate, resulting in sedimentation.

Solution:

Use suitable dispersants (such as high-performance polymeric dispersants or hydrophilic dispersants) to optimize the dispersion process.

Optimize the dispersion process to ensure that pigments and fillers are evenly dispersed, preventing particle aggregation.

6. Incompatibility of Coating Components

Issue: Different components of the coating, such as resins, solvents, pigments, and fillers, may not be compatible, leading to phase separation or sedimentation.

Cause: Poor compatibility between components, especially when using different types of resins or solvents, can result in instability in the coating system.

Solution:

Choose compatible raw materials to ensure proper interaction between resins, solvents, and fillers.

Conduct formulation optimization to ensure that the coating system remains stable during both storage and application.

In conclusion, addressing sedimentation issues in coatings involves optimizing formulations, selecting suitable dispersants, thickeners, and rheological modifiers, and ensuring good balance between flow properties and suspension stability. Additionally, the formulation and process should be adjusted based on the specific storage and application conditions.