ACEMATT® matting powder is used for the matting of water-based coatings (Part 1)

The extinction mechanism of ACEMATT® matting powder in water-based coatings is the same as that of solvent-based coatings.

Whether it is solvent-based coatings or water-based coatings, there are many factors that affect matting

This topic will be divided into two parts, the selection and application of ACEMATT® matting powder for water-based paint matting will be expanded in detail

Index of this content

• Comparison of properties and processes of ACEMATT® matting powders of different grades

• How to choose the right matting powder 

01

ACEMATT® different grades

Performance and process comparison of matting powder 

Evonik ACEMATT® matting powder is a white, fluffy, and amorphous silica powder

According to the production process, it can be divided into precipitated silica matting powder and fumed silica matting powder; one part is surface-treated, and the other part is not surface-treated

The surface-treated silica matting powder will improve its anti-settling properties and feel

All ACEMATT® matting powders of Evonik have the advantages of narrow particle size distribution and easy dispersion.

For water-based coatings with usual film thickness and no special performance requirements, the particle size of ACEMATT® grades should be referred to when selecting matting powder

02

How to choose the right matting powder 

For water-based varnishes, if there is a requirement for transparency, ACEMATT® matting powder with gas phase process is more suitable
.
For example, Evonik’s classic brands ACEMATT® TS 100 and ACEMATT® 3300
.

For special handle requirements, such as elastic handle, ACEMATT® OK 520, ACEMATT® TS 100, ACEMATT® 3300 are recommended
.

Unlike solvent-based coatings, water-based coatings have a very important parameter: pH
.
When silica is in weakly alkaline conditions, the zeta potential is larger, and the fully dispersed silica particles have a larger charge.
The silica particles repel each other and have good stability, so as to prevent the silica particles from flocculating and returning.
Problems such as roughness and settlement
.

Evonik's ACEMATT® matting powder has a suitable pH range between 8.
0 and 9.
5
.
Please try to avoid the use of pH regulators such as ammonia that can easily cause pH fluctuations, otherwise it may cause the Zeta potential to fluctuate and cause problems such as flocculation, coarsening, and even sedimentation
.

Thickeners are often used in water-based coatings, including associative thickeners
.
When ACEMATT® matting powder is added to high-gloss water-based coatings, the viscosity may decrease, but after a period of storage, the post-thickening is obvious
.
The reason is that at the beginning of the production of matt water-based paint, the associative thickener in the adsorption part of the added silica matting powder destroyed the three-dimensional network structure, resulting in a decrease in viscosity
.

To achieve the viscosity of the original high-gloss water-based paint, you need to increase the amount of associative thickener; after the matte water-based paint is stored, the silica matting powder will release part of the adsorbed associative thickener, resulting in obvious After thickening
.

▲Associative thickener

▲Silica adsorption thickener

ACEMATT® 3300 is a matting powder treated with a special surface process.
It has less adsorption of associative thickeners and has good viscosity stability during the production and storage of water-based coatings
.

As can be seen from the figure below, in water-based two-component polyurethane coatings, to achieve the same initial viscosity, ACEMATT® 3300 requires the least amount of associative thickener added; it is stored at 40°C for 5 weeks Afterwards, ACEMATT® 3300 has little change in viscosity and no post-thickening phenomenon
.