Matting is a popular effect for wood flooring in many parts of the world, adding a softer, more natural feel with little to no sheen compared to gloss finishes. With their low reflectivity, matt finishes can better hide flooring scratches and surface imperfections.
To achieve a matt coating effect, formulators have a few matting agent options, mixing silica, micronized waxes or fillers with coatings to impart a matt finish on the wood substrate. Silica is the most widely used agent.
In deep matt UV coatings applications on substrates like wood, typically high amounts of silica need to be used in the formulations – amounts as high as 10% and more. A major drawback of using such high levels of additives is a significant increase in viscosity, which makes the coating application more difficult. High loads of this inorganic material can also have a negative influence on mechanical coating properties, including creating film that’s brittle.
Handling silica can create its own challenges because silica powder is very lightweight and tends to be dusty and can spread through the air when trying to incorporate it into liquid, especially when used in higher volumes. Solid silica agents are efficient at delivering the matt effect, which is done by the light coming onto the substrate surface being scattered by the silica particles distributed in the coating surface and coating matrix.
Liquid matting agents – like the specialty Lubrizol Carbocure™ 7000 – are an alternative to silica powder and are easier to handle and incorporate into a homogeneous mixture. In the case of Carbocure 7000, it uses a unique matting mechanism to create an irregular surface that scatters the light to create the matting effect. The challenge with liquid matting agents is that they are used much less frequently than powder matting agents in wood coatings. Most formulators are set up to use solid powder matting agents.
With that in mind, the question becomes: How to overcome the drawbacks and challenges that silica powder brings?
Wax-Treated Silica
Lubrizol developed a wax-treated silica in the form of a solid powder for UV matting. It combines the powdered particulate effect with the specialized wax effect of Carbocure 7000 in a new, unique matting agent to create the desired matting effect in wood coatings.
The new wax-treated silica delivers very efficient matting performance at lower dosage levels while having very low impact on viscosity. It enables higher dosage levels for deeper matting and provides final coatings that are easy to process.
The new Lubrizol additive is unique in that it combines the performance, ease of handling and free flowing nature of a liquid matting agent and the performance of a silica powder matting agent in one product that is easy to incorporate – without the dust or the need to use high amounts of silica.
While treating silica is not a new approach, the new additive overcomes issues of other modified or treated silica matting agents to provide matting in UV cured coatings without sacrificing applicability and coating performance.
Contact us to learn more about our new specialty wax-treated silica agent for UV matting.
