Extensibility

The elasticity of a coating film is an important parameter that describes the ability of a coating to adapt elastically to the deformation of the underlying substrate without cracking or flaking. This aspect is particularly relevant in areas of application in which coated materials are exposed to mechanical loads or changes in shape, such as sheet metal processing in the automotive industry or in the construction industry.

A high stretchability of the coating film ensures that the protective and aesthetic properties of the coating are maintained even under dynamic loads. Standardized tests, such as the Erichsen depth test or the mandrel bending test, are carried out to check the elasticity. In these tests, the coated material is mechanically deformed under defined conditions in order to determine the load limit of the coating.

The composition of the coating material, in particular the choice of binders, additives and pigments, has a major influence on elasticity. Flexible coatings must be both elastic and robust enough to withstand stresses without losing their adhesion to the substrate. The ability of a coating film to resist deformation without losing its functionality is critical to its longevity and the protection of the substrate, especially in demanding environments or under changing loads.