Polyurethane thickeners

摘要

The present invention relates to a single-stage process for preparing polyurethanes which comprise at least three hydrophilic sections, at least four hydrophobic sections, optionally allophanate segments and optionally isocyanurate segments, in the presence of alkali(ne earth) metal carboxylates or zinc carboxylates. Furthermore, the present invention relates to the polyurethanes themselves obtainable in this way, to the use thereof as thickeners for aqueous preparations, and to aqueous preparations comprising polyurethanes of this type.

主权项

1. A process for preparing polyurethanes comprising
preparing a mixture comprising: at least one polyetherdiol, at least one alkoxylated alcohol, and a catalyst comprising at least one carboxylic acid salt of at least one metal selected from the group consisting of alkali metals, alkaline earth metals, zinc and mixtures thereof, wherein the mixture comprises less than 10 ppm of tin; providing at least one diisocyanate to the mixture to form a reaction mixture; and reacting the reaction mixture to form the polyurethanes in a single stage process; wherein the polyurethanes comprise
I) at least two hydrophilic sections S,II) at least one hydrophilic section P different from S,III) at least two terminal hydrophobic sections T,IV) at least two hydrophobic sections D different from T,and whereina) to each section T is directly attached a section S,b) to each section S on at least one side is attached at least one section D,c) to each section P are attached at least two sections D.