The sun is about 150 million km away from the earth and is known to be a prerequisite for the evolution on earth as we know it. In the human body, the sun’s rays are responsible for vitamin D production. However, the sun can also cause negative consequences such as sunburn or skin cancer.

Plastics can also suffer from UV radiation. This often results in yellowing, loss of color strength, cracking, brittleness, loss of strength or aging of the materials.

UV light, especially in aromatic polyurethanes, can lead to the breaking of the urethane bond, a rearrangement reaction followed by colored by-products or oxidation of the isocyanate (yellow or brown discoloration). Aliphatic polyurethanes are generally very UV stable and can also exhibit high transparency.

Human skin can be protected with sun cream. Here, the UVA and UVB radiation is absorbed by UV absorbers or the radiation reflects on mineral particles.

Polyurethane is usually protected from UV radiation with a mixture of UV absorber and UV stabilizer. The absorber catches the light of a certain wavelength and the stabilizer removes the radicals created by radiation. Thus, polyurethane can also have good UV resistance and color strength.

We at asma respond individually to your application conditions and can offer polyurethane coatings, wheels and rollers, but also technical molded parts with good UV resistance.


A Report of DI Dr.techn Patrick Steinbauer – asma development department

UV-resistance - PUR - Polyurethane