"Resin" is just a marketing term for plastic. Plastics vary widely in composition, even within the same chemical family. That is, there are MANY 'flavors' of PVC, or polyethylene. Only your pool's maker knows the makeup of the "resin" in their top rails, especially since it might have changed from 2011 to 2012!

So, the only people who could actually answer your question are the people who mold the rails. But, even they would probably NOT consider getting
Flaky/Chalky after a few years.
a failure, so if that's a primary concern, you might want to look at other products.