Basf Aktiengesellschaft

Stefan Wolff

Bernd Bruchmann

Hans Renz

Wolfgang Heider

Hermann Graf

Gerhard Laqua

Werner Langer

Franz Merger

Rainer Becker

Tom Witzel

Ludwig Schuster

Andreas Otterbach

Klaus Bittins

Konrad Stiefenhoefer

Ernst Deuker

Peter Brandt

Frank Wingerter

Guenter Mohrhardt

Joachim Jähme

Konrad Stiefenhofer

Richard Hardt

Serge Wack

A process for the preparation of polyisocyanates which contain one or more biuret groups, by reacting

Preparation of biuret-containing polyisocyanates

Process and device for preparing (cyclo)aliphatic biuret

Highly functionalized polyurethanes

A process for decoloring polyisocyanates containing isocyanurate and uretdione groups comprises treating the demonomerized polyisocyanates containing isocyanurate and uretdione groups with oxygen.

Decoloration of polyisocyanates containing isocyanurate and diretdione

Stable (cyclo)aliphatic polyisocyanate compositions obtainable by phosgene-free methods, preferably by thermal cleavage of (cyclo)aliphatic polycarbamates, are stabilized with carbon dioxide, advantageously in an amount of up to 0.3% by weight.

Stable polyisocyanate copositions obtainable by phosgene-free methods

The invention is to a process for the preparation of biuret-containing polyisocyanates by catalytic reaction of aliphatic and/or cycloaliphatic diisocyanates with a biuretizing agent, where the biuretizing agent employed is water in finely disperse form and the reaction is carried out in the presence of OH-acidic compounds.

Polyisocyanates containing isocyanurate groups are prepared by a partial trimerization of (cyclo)aliphatic diisocyanates in the presence of at least one trimerization catalyst selected from the group consisting of tetraalkylammonium alkyl carbonates of the formula (I) ##STR1## (quaternary ammonioalkyl) carbonates having a betaine structure of the formula (II) ##STR2## and the preferred use of the polyisocyanates containing isocyanurate groups which are obtainable in this way is aspolyisocyanate component in polyurethane finishes.

Preparation of polyisocyanates containing isocyanurate groups and use

Isocyanurate- and/or uretidone-containing polyisocyanates having a reduced color index and improved shelf life are prepared by conventional catalytic oligomerization of aliphatic and/or cycloaliphatic diisocyanates and treatment of the oligomerization products with peroxycarboxylic acids.

Preparation of isocyanurate- and/or uretidone-containing polysiocyanates

A process for the preparation of isocyanurate and urethane group-containing and, if desired, uretdiode and allophanate group-containing polyisocyanate mixtures by partially cyclizing organic, preferably (cyclo)aliphatic diisocyanates, in the presence of trimerization catalysts, deactivating these catalysts, reacting the partially trimerized, isocyanurate and, if desired, uretdiode group-containing polyisocyanate mixture with 0.5 to 10 mol % of at least one aliphatic or cycloaliphatic alcohol and/or polyoxyalkylene alcohol, and separating off the monomeric diisocyanates.

Preparation of low-viscosity, isocyanurate and urethane group-containing

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Limburgerhof, Germany

Stefan Wolff