No Yellowing upon Ageing

Polyurethane coatings made from aliphatic polyisocyanates are well known for their non yellowing properties upon ageing thanks to:

• The lack of phenyl group
  It makes polyurethane coatings prepared from aliphatic polyisocyanates less prone to oxidation rather than those prepared with an aromatic hardener
• The resistance of the urethane bond when exposed to UV light

The use of aliphatic polyisocyanates is particularly suitable when coatings have to play a durable decorative role. In the automotive market, the topcoat needs to stay as transparent as possible in order to maintain special effects and colors at their best level.

In these typical applications, polyurethane coatings made from aliphatic polyisocyanates are recommended for their no-yellowing property as for their exceptional physical resistance.

Figure 1: Impact of the type of polyisocyanates on color retention