Wolfgang Diener

Emulsifiers with high chemical resistance : a key to high performance waterborne coatings

A powerful way to coatings with low volatile content are waterborne systems. They are an important alternative to high solid- and powder coatings. It is essential, that waterborne coatings should not have a lower property level compared with conventional systems. A novel type of emulsifier allows the preparation of non-ionic stabilized aqueous emulsions. The main advantage of this new type of emulsifier consists in improving the chemical resistance of the resulting crosslinked films, especially against acids. There upon they show no discoloring even at high staving temperatures and a very good emulsifying behavior. The base type can be easily functionalized with a multitude of chemical functionalities like -OH, -COOH or vinyl groups. That means the emulsifier can be incorporated in the film during the crosslinking reaction. A migration to the coating surface can be avoided under these conditions. The different synthesis routes will be described in detail. A comparison of three non-ionic stabilized waterborne automotive coating systems with different crosslinking reactions (polyurethane, transetherifying and nucleophilic addition) with the corresponding ionic stabilized systems shows the extraordinary quality of the new tones of emulsifiers.