In contrast to their aromatic counterparts TDI and MDI (for more information - ISOPA) aliphatic diisocyanate monomers are key raw materials for light-stable, non-yellowingpolyurethanes. Aliphatic and aromatic diisocyanates are reactive chemical substances, reacting more or less quickly and exothermally with compounds being acidic, i.e. H+-donors like alcohols, amines and water. Polyurethanes are formed via polyadditon of polyols (polyester-, polyether-, polycarbonate-, poly(meth)acrylate-) to di- or polyisocyanates. Polyurethanes are typically of high molecular weight and often crosslinked. They are exhibiting outstanding mechanical properties (e.g. tear-, abrasion resistance) and chemical resistance. In addition to this, aliphatic polyurethanes are characterized by an excellent weathering resistance und colour stability. This is the reason why aliphatic polyurethanes are predominantely used in the field of coatings where light stability is essential. Polyurethane coatings show a superior performance compared to most other coating systems with regard to mechanical properties, chemical restistance and weathering durability. In a lot of applications aliphatic polyurethane coatings are the benchmark technology (link to “applications). Other important applications beside coatings are adhesives, sealants, elastomers and other applications.