Process for the manufacturing of a polymer with urethane groups, wherein in a first alternative a compound A) with at least two five-membered cyclic monothiocarbonate groups and a compound B) with at least two amino groups, selected from primary or secondary amino groups and optionally a compound C) with at least one functional group that reacts with a group —SH are reacted or wherein in a second alternative a compound A) with at least two five-membered cyclic monothiocarbonate groups or a mixture of a compound A) with a compound A1) with one five-membered cyclic monothiocarbonate group and a compound B) with at least two amino groups, selected from primary or secondary amino groups or a compound B1) with one amino group selected from primary or secondary amino groups or mixtures of compounds B) and B1) and a compound C) with 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 C) with at least one carbon-carbon triple bond. are reacted.