Bayer Materialscience Ag

Bayer Materialscience, LLC

Bayer Intellectual Property Gmbh

James Rawlins

Hans-Josef Laas

Reinhard Halpaap

Christoph Gürtler

Peter Thometzek

Michael Grahl

Ramesh Subramanian

Eric J Vidra

Thomas Faecke

Hans Josef Laas

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&#xb0; C. and liquid above 130&#xb0; 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. %.

Polyisocyanate-modified polycarboxylic acids

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&#xb0; 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&#xb0; C. and a liquid above 160&#xb0; C.

Carboxy-functional crosslinkers for epoxy-functional powder-lacquer binding agents

A solid isocyanate-based composition having a glass transition temperature of at least 30&#xb0; C. is produced by at least partially blocking the isocyanate groups of a polyisocyanate with a compound corresponding to the specified Formula I. This blocked isocyanate composition is useful in the production of powder coatings which are capable of being cured at temperatures of from 80 to 220&#xb0; C.

Powder coatings produced with crosslinkers capable of curing at low temperatures and coated articles produced therefrom

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Leverkusen, Germany

James Rawlins