What is the real difference between these two? It’s quite simple. UV stable polyurethanes, or aliphatic to scientists, retain their clear colour and are unaffected by UV radiation. Non-UV polyurethanes, on the other hand, turn a darker brown when exposed to UV light. UV is required if you want the resin-bound surface to retain its original colour. It is important to use UV when you are using light or coloured aggregates. Otherwise, the final product will not look the same.
Non-UV can be fine if the aggregate is yellow/brown. However there is a possibility of colour variations due to shading. ).