Binders are macromolecular products with a molecular mass between 500 and ca. 30000. The higher molecular mass products are suitable for physical film formation. With The low molecular mass product, to produce acceptable films, these binders must be chemically hardened after application to the substrate to produce high molecular mass cross-linked macromolecules. Increasing relative molecular mass of the binder in the polymer film improves properties such as elasticity, hardness, and impact deformation, but also leads to higher solution viscosity of the binder. While the usefulness of a coating is enhanced by good mechanical film properties, low viscosity combined with low solvent content are also desirable for ease of application and for environmental reasons. Therefore, a compromise is necessary. The low molecular mass binders have low solution viscosity and allow low-emission paints with high solids contents or even solvent-free paints to be produced. Here, the binder consists of a mixture of several reactive components, and film formation takes place by chemical drying after application of the paint. If chemical hardening occurs even at room temperature, the binder components must be mixed together shortly before or even during application (two- and multi component systems).