A polymer obtainable by a process comprising the steps a) and b): a) condensation of at least one component a1), optionally at least one component a2) and/or optionally at least one component a3), which are defined as follows: a1) is at least one compound selected from N-(hydroxyalkyl)amines of formulae (I.a) and/or (I.b), wherein A are independently selected from C 1 -C 6 -alkylene, R 1, R 1*, R 2, R 2*, R 3, R 3*, R 4, R 4*, R 5, R 5* and R 6 are independently of one another selected from hydrogen, alkyl, cycloalkyl or aryl, wherein the last three mentioned radicals may be optionally substituted, and a2) is at least one compound selected from polyols of formula Y n, wherein n is an integer from 2 to 4 and Y denotes a bivalent, trivalent or tetravalent aliphatic, cyclo-aliphatic or aromatic radical having 2 to 10 carbon atoms, and a3) is at least one compound selected from polyamines of formula Y'(NHR y) m, wherein m is an integer from 2 to 4, Y denotes a bivalent, trivalent or tetravalent aliphatic, cyclo-aliphatic or aromatic radical having 2 to 10 carbon atoms, and R y has one of the meanings given for R 6 or two radicals R y together may form a C 1 -C 6 -alkylene group, wherein the sum of the amount of components a1), a2) and a3) is more than 70 wt.-% in relation to the sum of the amount of all monomers employed in the condensation according to step a) in order to obtain a polyether having remaining hydroxyl groups and optionally remaining secondary amino groups, b) reacting a part of the remaining hydroxy groups and optionally a part of the remaining secondary amino groups of the polyether obtained in step a) with at least one alkylene oxide, wherein the ratio of i) the alkylene oxide versus ii) the sum of the amount of the remaining hydroxyl groups and optionally the remaining secondary amino groups is > 0: 1 to < 1: 1 [mol/mol]. a) condensation of at least one component a1), optionally at least one component a2) and/or optionally at least one component a3), which are defined as follows: a1) is at least one compound selected from N-(hydroxyalkyl)amines of formulae (I.a) and/or (I.b), wherein A are independently selected from C 1 -C 6 -alkylene, R 1, R 1*, R 2, R 2*, R 3, R 3*, R 4, R 4*, R 5, R 5* and R 6 are independently of one another selected from hydrogen, alkyl, cycloalkyl or aryl, wherein the last three mentioned radicals may be optionally substituted, and a2) is at least one compound selected from polyols of formula Y n, wherein n is an integer from 2 to 4 and Y denotes a bivalent, trivalent or tetravalent aliphatic, cyclo-aliphatic or aromatic radical having 2 to 10 carbon atoms, and a3) is at least one compound selected from polyamines of formula Y'(NHR y) m, wherein m is an integer from 2 to 4, Y denotes a bivalent, trivalent or tetravalent aliphatic, cyclo-aliphatic or aromatic radical having 2 to 10 carbon atoms, and R y has one of the meanings given for R 6 or two radicals R y together may form a C 1 -C 6 -alkylene group, wherein the sum of the amount of components a1), a2) and a3) is more than 70 wt.-% in relation to the sum of the amount of all monomers employed in the condensation according to step a) in order to obtain a polyether having remaining hydroxyl groups and optionally remaining secondary amino groups, a1) is at least one compound selected from N-(hydroxyalkyl)amines of formulae (I.a) and/or (I.b), wherein A are independently selected from C 1 -C 6 -alkylene, R 1, R 1*, R 2, R 2*, R 3, R 3*, R 4, R 4*, R 5, R 5* and R 6 are independently of one another selected from hydrogen, alkyl, cycloalkyl or aryl, wherein the last three mentioned radicals may be optionally substituted, and A are independently selected from C 1 -C 6 -alkylene, R 1, R 1*, R 2, R 2*, R 3, R 3*, R 4, R 4*, R 5, R 5* and R 6 are independently of one another selected from hydrogen, alkyl, cycloalkyl or aryl, wherein the last three mentioned radicals may be optionally substituted, and a2) is at least one compound selected from polyols of formula Y n, wherein n is an integer from 2 to 4 and Y denotes a bivalent, trivalent or tetravalent aliphatic, cyclo-aliphatic or aromatic radical having 2 to 10 carbon atoms, and n is an integer from 2 to 4 and Y denotes a bivalent, trivalent or tetravalent aliphatic, cyclo-aliphatic or aromatic radical having 2 to 10 carbon atoms, and a3) is at least one compound selected from polyamines of formula Y'(NHR y) m, wherein m is an integer from 2 to 4, Y denotes a bivalent, trivalent or tetravalent aliphatic, cyclo-aliphatic or aromatic radical having 2 to 10 carbon atoms, and R y has one of the meanings given for R 6 or two radicals R y together may form a C 1 -C 6 -alkylene group, wherein the sum of the amount of components a1), a2) and a3) is more than 70 wt.-% in relation to the sum of the amount of all monomers employed in the condensation according to step a) in order to obtain a polyether having remaining hydroxyl groups and optionally remaining secondary amino groups, m is an integer from 2 to 4, Y denotes a bivalent, trivalent or tetravalent aliphatic, cyclo-aliphatic or aromatic radical having 2 to 10 carbon atoms, and R y has one of the meanings given for R 6 or two radicals R y together may form a C 1 -C 6 -alkylene group, b) reacting a part of the remaining hydroxy groups and optionally a part of the remaining secondary amino groups of the polyether obtained in step a) with at least one alkylene oxide, wherein the ratio of i) the alkylene oxide versus ii) the sum of the amount of the remaining hydroxyl groups and optionally the remaining secondary amino groups is > 0: 1 to < 1: 1 [mol/mol].