Matt powder viscosity reducing dispersant: Master the usage skills to improve application efficiency

Matt powder viscosity reducing dispersant is an additive specially used to reduce the viscosity of matte powder (such as silica, wax powder, etc.) in coatings, inks, plastics and other systems. At the same time, it can effectively improve the dispersibility of matte powder and avoid agglomeration. The following are its usage methods and precautions, which are explained in points as follows:

1. Preparation before use

Understand the characteristics of the system

Confirm the type of matte powder (such as particle size, specific surface area), substrate type (water-based/solvent-based/UV system), and target viscosity range.

For example: in water-based coatings, matte powder is easy to absorb water and agglomerate, so a hydrophilic dispersant needs to be selected; solvent-based systems require dispersants with strong solvent resistance.

Dispersant selection

Select matching dispersants according to the characteristics of matte powder:

Small particle size matte powder (such as nanometer): a dispersant with high anchor group density (such as containing polycarboxylic acid groups) is required.

Large particle size matte powder (such as micrometer): a low molecular weight dispersant (such as polyurethane) can be selected.

Mat powder with high oil absorption (such as carbon black): a dispersant with high solvation chain length (such as long-chain polyester) is required.

Pre-dispersion test

Take a small amount of matt powder and dispersant and mix them in the recommended proportion, add a small amount of solvent or water, and observe the dispersion state after stirring (such as whether there is floating color, precipitation, and viscosity change).

2. Usage method

Adding time

Pre-dispersion stage: pre-mix the matt powder and dispersant first (the recommended proportion is 10%-30% of the mass of the matt powder, which needs to be adjusted by experiment), and then add them to the substrate.

Dynamic dispersion stage: add the premixed liquid in batches in a high-speed disperser (such as a sand mill, a three-roller mill), and continue to disperse to the target fineness (such as ≤15μm).

Dispersion process

Water-based system: recommended speed 500-1500rpm, dispersion time 20-60 minutes, temperature ≤50℃.

Solvent-based system: the speed can be appropriately increased (such as 1000-3000rpm), and the temperature can be adjusted according to the boiling point of the solvent (such as 60-80℃).

Dispersion end point judgment: use a scraper fineness meter or a laser particle size analyzer to ensure that the matt powder particle size distribution is uniform.

Dosage optimization

The initial addition amount is recommended to be 10%-50% of the matte powder mass, and it is adjusted according to the viscosity test results:

Viscosity is too high: increase the amount of dispersant appropriately (increase 5%-10% each time).

Viscosity is too low or floating color: reduce the amount of dispersant or change the type.

3. Common problems and solutions

Matte powder agglomeration

Reason: insufficient dispersant dosage, insufficient dispersion time, inappropriate pH value.

Solution: increase the amount of dispersant, extend the dispersion time, and adjust the system pH to near the isoelectric point of the matte powder (such as silica pH 4-6).

Viscosity rebound

Reason: poor compatibility between dispersant and substrate, matte powder is not completely wrapped.

Solution: Change the dispersant type (such as from anionic to non-ionic), or add a small amount of leveling agent for synergistic effect.

Poor storage stability

Reason: insufficient heat resistance of dispersant, too large particle size of matte powder.

Solution: Select a heat-resistant dispersant and optimize the particle size of matte powder (such as reducing it to less than 10μm by grinding).

4. Precautions

Safety

Avoid direct contact with strong acids and alkalis. Some dispersants may contain organic solvents, so protective equipment must be worn.

System compatibility

Water-based dispersants cannot be used in solvent-based systems, and vice versa.

Test the compatibility of dispersants with resins, curing agents, pigments and other components to avoid flocculation.

Long-term stability

Storage temperature is recommended to be ≤40℃, avoid direct sunlight.

Use as soon as possible after opening to prevent moisture absorption or oxidation.