Simply mixing in a wonder-additive is very unlikely to create a functional coating
Sometimes the description “functional coating” is barely more than a buzzword that is describing standard properties of more or less every paint and varnish, that is sold nowadays. However, that is not enough. For Volkmar Stenzel from the Fraunhofer Institute for Manufacturing and Advanced Materials IFAM the definition is more distinct. “We consider functional coatings to be coatings having novel surface functions beyond classical decoration, corrosion protection, and surface protection”, says Stenzel.
Self-healing coatings will spread
Dr Volkmar Stenzel, Head of Department Coatings, Fraunhofer IFAM
Other examples are of recently developed and commercially ready functionalities are self-healing coatings for wood protection that use microcapsules. “It is very likely that other applications based on microcapsules will follow in the near future, such as coatings for heavy-duty corrosion protection and for damage indication”, says Stenzel and adds: “Other new surface functions that are on the threshold of commercialisation are coatings for icing protection, coatings for drag reduction for aircraft and wind turbines as well as elastomeric erosion resistant coatings having dirt-repelling or easy-to-clean properties.”
An even more visionary trend is seen by Riemer: “Blending paints with functional biogenic materials such as enzymes could be used is for formulating coatings with antimicrobial properties.” He also sees easy-to-clean properties on the rise and intumescent coatings for fire protection.
Market ready functionalities need time
Dr Christoph Riemer, Vice President Consumer & Industrial Polymers, Wacker Polymers
However, getting these coatings market-ready is rarely easy. “It is, for instance, not very difficult to create a surface that is extremely hydrophobic with a water contact angle of 150°. The major challenge is to make these approaches feasible for industrial use”, says Stenzel. “Given how complex chemical interactions are in formulation and manufacturing processes, this represents a significant challenge”, adds Christoph Riemer.
Volkmar Stenzel does not believe in wonder additives and explains that “the development of a coating system with new functions normally requires substantial modification of the formulation which means that such coatings typically have to be developed from scratch.”
Hybrid systems for functional coatings
At Wacker the use of hybrid systems is seen as a good possibility to create new functionalities in coatings. “Combining particle technologies with silanes, siloxanes and polymers results in hybrid materials with completely new properties – properties that enable innovative solutions in both new and existing fields”, explains Riemer.
The quotes in this article are taken from our monthly expert voices series in the European Coatings Journal 7+8/2018. Subscribers of the digital library European Coatings 360° can read the complete interview online.
To get more knowledge on this topic, visiting the European Coatings Seminar Functional Coatings on 14 November, 2018 in Amsterdam is a good opportunity.