Do you have an old dark jacket? Will it protect from UV? It may get soaked, but I don't think you won't get sunburnt through it.
We have a main and working jib from North Sails Marathon 3DL is very resistant to UV degradation. We've had them since 2011. They are aramid (Kevlar) and carbon fiber. There may different 3DL laminates (or older ones), but we are very happy with our main and jib.