Solventborne paints have demonstrated over decades that they are easy to handle and are distinguished by a very wide processing window. The technology is reliable and established worldwide. However, since EC Directive 1999/13 came into force, many solventborne paints in European countries no longer meet the regulations for reducing organic volatiles.
Experience shows that, with conventional binder technology, it is not possible to formulate high-solids paints with fewer than 250 g/l VOC. Simply reducing the solvent content in existing medium-solids paints to meet legal requirements results in a highly viscous paint which cannot be applied. To simply reduce the non-volatile components (NVC) in paints requires major changes in the molecular structure of the binder.
Reduction in molecular weight, improved dilutability of the resin in common solvents, and lower intermolecular interaction are just some of the fundamental demands on innovative high-solids binders. The challenge is to increase the NVC at working viscosity to comply with the regulations, without impairing drying (both touch and complete), optical appearance, or mechanical and chemical resistance.