Specially selected polycarboxylic hydrazides can also be used to achieve one-component, moisture-curing polyurethane adhesives with excellent storage stability. Azelaic acid dihydrazide, a type of carboxylic hydrazide, can be used as a pharmaceutical synthesis intermediate and in the preparation of adhesives.
With the polycarboxyhydrazide HY it is particularly also possible to formulate one-component polyurethane adhesives which store extremely well at temperatures up to about 60 C. Carboxyhydrazide is in the present invention a constituent of cured polyurethane adhesives, wherein it is present in free form, i.e. with a chemically invariant hydrazide group, and is therefore not built into the polyurethane polymer of the adhesive, but dispersed therein as a solid. Upon heating said adhesive, surprisingly the carboxyhydrazide begins to react with the polyurethane polymer. Particularly suitable as polycarboxyhydrazide HY are oxalic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, octanedioic acid dihydrazide, nonanedioic acid dihydrazide, sebacic acid dihydrazide, dodecanedicarboxylic acid dihydrazide and isophthalic acid dihydrazide.
