Polyurethane thickeners

摘要

The present invention relates to a process for preparing polyurethanes, which comprise at least three hydrophilic sections, at least four hydrophobic sections, optionally allophanate segments and/or isocyanurate segments and which are prepared in the presence of alkali(ne earth) metal carboxylates. The process may comprise using at least one carboxylic acid salt of at least one metal selected from the group consisting of the alkali metals, the alkaline earth metals and mixtures thereof Furthermore, the present invention relates to the polyurethanes per se obtainable in this way, to the use thereof as thickeners for aqueous preparations, and to preparations comprising polyurethanes of this type.

主权项

1. A process for preparing polyurethanes comprising:
preparing a first mixture comprising: at least one polyetherdiol, at least one alkoxylated alcohol, and a catalyst comprising at least one potassium carboxylate; providing at least one diisocyanate to the first mixture to form a reaction mixture; and reacting the reaction mixture to form the polyurethanes; 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 wherein
a) 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, wherein preparation of the polyurethanes takes place in the presence of less than 10 ppm of tin, and less than 10 ppm zinc, and wherein the process is single-stage, and wherein at least some of the polyurethanes comprise allophanate segments that are formed in situ or isocyanurate segments that are formed in situ.