which filament is most sun/heat/UV resistant

[jackstraw77]

I dove into FDM printing last year to make my own custom tool organizer box inserts for Milwaukee and Ridgid because I didn't see exactly what I wanted from others and wound up having a blast getting into it, designed a ton of permutations of depth, divider configurations I didn't see anywhere else for niche purposes and received enough interest from friends that I might actually make a go of making this a side hustle. But before doing that I field tested them for a while and noticed that the deep cups with long unsupported walls cups tended to warp after moderate sun exposure. The thickness of them was the same as some free templates I found online so I figured that was probably good enough. They were in a combination of PLA and PETG which I stupidly forgot to label, but I'm fairly certain based on the sheen of the cups that the PETG was less stable than the PLA, but the PLA cups might just have been more stable because of shape of the internal dividers.The first thought is to simply make the walls thicker but can't be sure if that will make much difference until we get to peak summer temps.In the meantime does anyone have either experience or direct materials knowledge to assert whether PLA or PETG is more stable with sun/heat/UV exposure? My intuition would have suggested to me that PETG might have an edge given the higher melting point, but that didn't seem to be the case (at least I'm pretty sure the ones that warped most were PETG). Black may not have been be the best choice either (chosen because i found it easiest to see stuff in when outdoors) but not sure if that will make a significant difference, eager to hear others' experiences.Again, my default plan at the moment is to simply make the walls a bit thicker but before going through the trouble tediously tweaking dozens of models without disturbing the outer dimensions I wanted to know if anyone had advice as far as which material was generally thought to be more reliable for such an application. The boxes don't need to be particularly strong, but do need to hold shape with exposure to ~90F temps for a few hours and moderate sun exposure. If it were just me I'd tell myself just don't leave them out in the sun, but I can't give these to others without at least attempting to bulletproof them. examples of the warpage attached. The shallower cups with more internal dividers bracing the perimeter seemed to hold up better but would have probably deformed with a bit more time in the sun.

[Bikeracer2020]

If you have an enclosed printer ASA would be a good choice, or possibly ASA-X. Also because of the nozzle temp around 250 you really need an all metal hot end with a heat break in it.