Okay,
I found this about a different Kayak "38 mil Polykrylar" Sounds tough enough-ish...
Enjoy!
"This kayak looks fantastic in white and engineered design for tough in any water conditions. Built with 38 mil PolyKrylar (K80 PVC) a super rugged material that can withstand up to class 3 white-waters when paddling on river, this includes sharp stones, dog paws and claws if wish to bring along your pet."
Article Source: http://EzineArticles.com/7158391