Über die Einwirkung von Wasser auf Anstrichfilme

The effect of water on paint coatings The water absorption of varnishes and organic coatings is normally known as “swelling”. In many cases, however, a homogeneous water absorption through swelling of the polymer substance is of lesser importance than a heterogeneous water absorption. The latter may occur at the inner interfaces of a lacquers or plastic coating, e.g. at the interface between coating base, at the interface between polymer substance (binder) and filler (pigment), or at the interfaces within the polymer substance itself. One important cause of heterogeneous water absorption is the occurence of osmotic processes which are caused by water soluble substances present or originating at the boundaries. With such absorption, the freezing temperature of the polymer substance plays an important part. It is possible to ascertain experimentally how polymer films are absorbing the water. In this way, the influence of water on the film properties can be better evaluated than by simply ascribing all the water intake to a swelling process.