Can the edding 5200 permanent spray be used for natural rubber, possibly with the application of a primer?
No, this will not work so well. Rubber is more or less flexible, depending on its shape. Even if our coating undergoes certain movements, we cannot guarantee that it will not crack. A primer has little influence in this case. Therefore we cannot recommend this application in principle. However, if the object is very compact/rigid and is not subjected to excessive mechanical stress after painting, it may work. With the universal primer the adhesion between rubber and paint is improved.