Process for the preparation of polyhydantoins which can be processed thermoplastically

摘要

Polyhydantoins of the type mentioned may be prepared by reacting initially in a first step, bis-glycine esters with between 1 and 2 moles of diisocyanate per mole of bis-glycine ester in a liquid reaction medium, and after forming the polyurea from this bis-glycine ester and the diisocyanate, by further reacting in a second step with an amount of a monoglycine ester equivalent to the residual amount of isocyanate end groups, and finally by carrying out the cyclocondensation to give the polyhydantoin by removing hydroxyl compounds.