Patent ID: 7655733

Claim:
A process for postcrosslinking a water absorbing polymer comprising: (a) reacting respectively an aminoalcohol or a diamine with a cyclic carbonate to free an n,m diol from the cyclic carbonate and provide at least one crude postcrosslinker comprising i) a cyclic carbamate having a hydroxyalkyl group on a nitrogen atom and the n,m diol, wherein a molar ratio of the n,m diol to the carbamate is in a range of 1.1:1 to 1:2.5, or ii) a cyclic urea optionally having a hydroxyalkyl group on a nitrogen atom and the n,m diol, wherein for i) and ii), m>n and m−n>1; (b) treating the water absorbing polymer with the at least one crude postcrosslinker of step (a); and (c) optionally raising a temperature of the treated water absorbing polymer during or after step (b) to postcrosslink the water absorbing polymer.