Anti-Graffiti
The aim of the project is to develop a hydrophilic selective-permanent coating with dirt- and graffiti-repellent properties. The basis for this is formed by hydrophilic and biobased polymer building blocks, which are reacted with various diisocyanates via a chain extension reaction in water to form an aqueous polyurethane dispersion. By applying the dispersion to different surfaces, a transparent water-resistant/hydrolyzable and thus renewable film with dirt- and graffiti-repellent properties is to be developed. The solution pursued here differs from the products currently on the market in that the anti-graffiti coating is hydrophilic. It thus follows the principle of soil release products, in which the removal of dirt is supported by the absorption of water in the release layer. The hydrophilic coating is able to absorb moisture from the environment and thus impede the primary wetting and adhesion of the graffiti coatings and paints. Furthermore, the hydrophilic structure of the coating eliminates the problem of water vapor diffusion limitation, which is common in the state of the art. The benefit for SMEs lies in the provision of the chemical basis for the development of a new type of protective concept from which new products can be formulated. The chosen approach will eliminate the usual disadvantages of existing products (water vapor limitation, poorly adjustable service life, use of expensive and unsustainable raw materials) and thus generate a significant competitive advantage for the SMEs. Furthermore, the planned manufacturing processes for the new coating have been selected in such a way that they can be easily implemented in existing manufacturing infrastructure, thus eliminating the need for major investments in production conversion.