Huels Aktiengesellschaft

Degussa Aktiengesellschaft

Degussa-huels Aktiengesellschaft

Klaus Janischewski

Hartwig Lange

Dirk Reichel

Martina Ortelt

Lutz Mindach

Klaus-Peter Jonderko

A blocked polyisocyanate adduct including 5 to 95% by weight of at least one isocyanate component having at least one NCO group, the isocyanate component selected from the group consisting of aliphatic, cycloaliphatic and aromatic isocyanates, wherein the isocyanate has an average molecular weight of up to 1000 g/mol and an average NCO functionality of 2&#x2013;4; 5 to 70% by weight of at least one hydrophilicizing component containing at least one group which is reactive toward the at least one NCO group; at least one blocking agent for blocking from 95 to 100% of the NCO groups which do not react with the hydrophilicizing component; and up to 15% by weight of at least one neutralizing agent.

Pulverulent, water-dispersible, blocked polyisocyanate adducts, a process for the preparation and their use

A stable and high-solids aqueous dispersion of blocked isocyanates, containing auxiliary solvent, is prepared by (1) preparing a solution of a polyisocyanate mixture of from 20-70% by weight of a blocked, hydrophilically modified polyisocyanate (A) and from 30-80% by weight of a blocked, hydrophobic polyisocyanate (B) in an auxiliary solvent (G) and (2) adding water to this solution, with intensive mixing, in an amount which is such as to give a two-phase system comprising a disperse polyisocyanate phase and a continuous, aqueous phase containing auxiliary solvent. In a preferred embodiment of the invention dispersions are prepared which are virtually free from auxiliary solvent, by first adding a portion of water to the solution (1), substantially removing the auxiliary solvent with intensive mixing and then adding a second portion of water with intensive mixing to the mixture comprising the polyisocyanates (A) and (B) and the first portion of water.

Stable and high solids aqueous dispersions of blocked polyisocyanates

A composition containing an unblocked monomeric diisocyanate finely dispersed an aqueous dispersion of at least one organic polyhydroxy compound. The composition may be used to prepare aqueously disperse two component polyurethane coatings where the diisocyanate functions as a curing agent and the polyhydroxy compound serves as a binder agent. In the composition, the ratio of hydroxyl groups in the polyhydroxy compound to the isocyanate groups in the diisocyanate is 0 5:1 to 5:1. The composition may be used to apply polyurethane coatings to substrates.

Aqueous two component polyurethane coatings, preparation thereof and use

Aqueous resin dispersions obtainable by reaction, or partial reaction, of

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Dorsten, Germany

Klaus Janischewski