Ideally a PUR product would be crosslinked if any of the isocyanate or the polyol component (or the chain extender) exhibits higher functionality than 2. Life is not easy, however, as in polyurethane chemistry there are side reactions (allophanate, urea, carbamate etc. formation) that may lead to crosslinked structures even if the basic structure consits of bifunctional components only. Several other reasons for crosslinking may also exist, such as radiation crosslinking, unsaturations in the polylol component, copolymerization (uerathane-acrylates, urethane epox sxystesm). Anyway it is a challenge to produce strictly thermoplastic polyurethanes (TPU). If this is not, what you are looking for, please specify further your question.

Thank you very much.... it is just what i was looking for...