When I have used Kevlar it comes from the manufacturer wrapped in black polythene to keep the light out. It is a very light straw colour when unwrapped. If you leave it out in daylight it takes about three weeks to turn to a beige colour. This indicates that it has lost
up to half its original tensile strength. After this it is reasonably stable.
As for laminates they have never really overcome the problem faced by a double column of soldiers marching round a corner. The inner column marks time while the outer has to take giant strides. When you apply this to fabric
you stretch the outer fold or delaminate and cause a bubble on the inner. Plastic has a memory and thus every fold becomes a weak point.This is probably more of a problem than UV
Great for racers but its hard to go past dacron for long term cruising
My two bobs worth.