November 14th, 2021
Evonik's Coating Additives Business Line is expanding its ACEMATT product line with three matting agents based on precipitated silica: the fine-particle products ACEMATT OK 390 and ACEMATT HK 390, and the silica ACEMATT HK 520. The three new silicas are claimed to be characterized by a combination of efficient, ultra-deep matting, high transparency, and fine surface haptics.
"Due to their transparency properties, they provide a deep matte surface without a milky white haze, especially in clear coatings," says Maximilian Morin, head of the Industrial & Transportation Coatings market segment. The main applications are coatings for plastics, for example, on laptops or smartphones, and wood coatings, such as parquet flooring, tabletops or kitchen countertops.
In wood applications especially, it is visually appealing to see the grain showing through the transparent coating. The matting silica claims to provide a glare-free matte surface in automotive interior applications, such as dashboards and trim. For exterior coatings, matte formulations are also becoming popular.
With the surface-treated ACEMATT OK 390 and its untreated counterpart ACEMATT HK 390, Evonik developers have produced matting silicas with small particle sizes. "As a result, they produce a fine surface feel," says Thomas Klotzbach, head of ACEMATT application technology. The special feature: Despite the small size of the particles, the same deep degree of matting is achieved with almost the same amount of powder as with products with larger particles. "This means the same efficiency without sacrificing transparency."
"Now the whole ACEMATT family consisting of surface-treated and untreated silica is complete," Morin says. "We have fine-particle matting agents in the portfolio, plus our tried-and-true ACEMATT OK 520 has been joined by an unwaxed variant, ACEMATT HK 520, which performs equally well."
One advantage of untreated silicas such as ACEMATT HK 390 and ACEMATT HK 520 over waxed silica is their better orientation in water-based systems. This prevents uneven particle distribution in some plastic coatings, resulting in a smooth, deep matte surface. In turn, the post-treatment of precipitated silica, as in the new ACEMATT OK 390, means that the product does not settle during storage and is, therefore, more stable in the coating.
The three new silicas score not only in terms of appearance and feel but also in terms of application by the paint manufacturer because they show little influence on the viscosity of the formulation and have excellent dispersion behaviour.
With the three new members of the ACEMATT family, Evonik is responding to changing requirements in the paint and coatings industry, where it says demand is growing for ever deeper degrees of matting, and high-quality waterborne coating systems and customers are looking for a fine feel in surface coatings.
