If you have unpigmented pure polymer without delustering agents the UV rays pass through the material and bust apart the chains of atoms that make up the polymer.
It doesn’t happen overnight but it happens eventually. We’ve all seen plastic bags rot in the sun, get brittle, haze up and then rupture.
If you prevent or inhibit the UV rays from passing through the material by dyeing the material (or impregnating with carbon) you can further improve the UV resistance and slow the degradation.
Black is the best colour to prevent UV entering the fibre...
SJBCH-P1 coated in black PVC
Black PVC coated heavy wire — SJBCH–P1
White PVC coated heavy wire — SJBCH–P2
Internal dimensions: 50mm front to back and 340mm side to side
Hook diameter 60mm internal diameter
Black PVC coated heavy wire — SJBCH–P5
White PVC coated heavy wire — SJBCH–P6
Internal dimensions: 120mm front to back and 340mm side to side