Abstract: A process for preparing polyisocyanate-modified polycarboxylic acids by conversion of anhydride-group-free polycarboxylic acids with isocyanate-functional compounds. The process includes reacting A) an anhydride-group-free polycarboxylic-acid component with B) an isocyanate-functional component having an (average) isocyanate functionality of at least 1.8, at an equivalent ratio of carboxylic acid groups to isocyanate groups of from 1.2:1 to 120:1. The polyisocyanate-modified polycarboxylic acids are solid below 40° C. and liquid above 130° C., and have an average carboxylic acid functionality of at least 1.8, a content of free carboxylic acid groups of from 4.0 wt. % to 80.0 wt. % and a content of amide groups of from 0.4 wt. % to 32.5 wt. %.

Abstract: The invention relates to the use of special mixtures of at least two polycarboxylic acids as crosslinker components for thermally curing powder-lacquer binding agents having groups that are capable of reacting with carboxyl groups. The mixtures include at least two polycarboxylic acids each melting above 95° C. and having up to 20 carbon atoms and consist of at least 5 wt. %, of the polycarboxylic acid with the lowest melting point and at least 10 wt. %, of the polycarboxylic acid with the highest melting point of all polycarboxylic acids present in the mixture to at least 5 wt. %. Additionally, the polycarboxylic acid mixture is a solid below 40° C. and a liquid above 160° C.

Abstract: The present invention relates to novel blocked, elimination-free polyurethane (PUR) crosslinking agents, to a process for their preparation and to their use as starting components for the production of polyurethane plastics, especially as crosslinking agents for thermally crosslinkable powder coatings.

Abstract: The invention relates to novel polyaddition compounds containing uretdione groups, to a process for preparing them and to their use as a starting component in the preparation of polyurethane plastics.

Abstract: The invention relates to new high-functional polyaddition compounds which contain free isocyanate groups with an average isocyanate functionality of 2.1 to 8.0, a concentration of uretdione of 10 to 18 wt. %, a concentration of urethane of 10 to 20 wt. % and a concentration of ester groups —CO—O and/or carbonate groups —O—CO—O of 1 to 17 wt. %, a process for the preparation thereof and their use as starting components for the preparation of polyurethane plastics, in particular as cross-linking agents for heat-curable powder coatings.

Abstract: The present invention relates to polyaddition compounds, which are solid below 40° C. and liquid above 125° C., are prepared by the reaction of an isocyanate component containing uretdione groups with a polyol containing ester and/or carbonate groups, other than hydroxypivalic acid neopentylglycol ester, and have a) an average isocyanate functionality of 2.0 to 8.0 and a content of free isocyanate groups (calculated as NCO; molecular weight=42) of 2.1 to 6.0 wt. %, b) a content of uretdione groups (calculated as C2N2O2; molecular weight=84) of 10 to 19 wt. %, c) a content of urethane groups (calculated as —NH—CO—O; molecular weight=59) of 10 to 17 wt. % and d) a content of ester groups —CO—O (calculated as —CO—O; molecular weight=44) and/or carbonate groups —O—CO—O (calculated as —CO—O; molecular weight=44) of 1 to 17 wt. %.