I've been working with a manufacturer to have some parts made. I contacted them recently for advice about how to make the parts slightly less brittle/more flexible and after a bit of a discussion, they just sent me three material data sheets for possible alternative plastics. I'm supposed to choose. However, I am not a material expert so this is outside of my wheelhouse and the data sheets are just long lists of numbers to me. Hoping that I can get some help from people here with experience with various types of plastic.

My first couple of orders used PA-12 with no fillers or additives. They came out fine but as I mentioned, slightly brittle so my end-users sometimes break them. The part is a dog muzzle and they sometimes try to rub them off against a fence or the ground. I don't expect them to be indestructible, just a bit more resilient. And they should also be somewhat non-toxic because dogs do sometimes chew them up and swallow small bits. The alternative plastics they suggested were generic nylon 6, generic nylon 66 and generic pp copolymer.

Thoughts?