Why does pp material harden when it is cold?

PVC materials themselves are divided into winter materials and summer materials. What you make is of course summer material and winter material. Not only that, there will be obvious white marks when folding by hand, which is easy to break.

If you order PVC products, you should first consider when to use them. When you order them, you must tell the factory what materials to use. I wonder if I can help you.