Object of the invention is a process for the manufacturing of a polymer with urethane groups, wherein in a first alternative A) a five-membered cyclic monothiocarbonate B) a compound with at least two amino groups, selected from primary or secondary amino groups, and C) a compound which at least two functional groups that react with a group —SH or, in case of a carbon-carbon triple bond as functional group that react with a group —SH, a compound with at least one carbon-carbon triple bond are reacted or wherein in a second alternative A) a five-membered cyclic monothiocarbonate and D) a compound with at least one primary or secondary amino group and at least one functional group that reacts with a group —SH.