Old nylon (pre 80s) was very badly affected, I think they added something which reduces this. However I've tested some gym draws, and Black Diamond tested lots of draws from caves that saw little UV but still broke at low loads.
Abrasion, cyclic fatigue, oxidation, crystalisation (nylon is amorphous and with time it may go into a more regular atomic pattern which can embrittle it) may all be part of the answer. |