PROCESS FOR THE PREPARATION OF AQUEOUS DISPERSIONS OR SOLUTIONS OF POLYURETHANE POLYUREAS CONTAINING HEAT ACTIVATED CROSS-LINKING AGENTS, THE DISPERSIONS OR SOLUTIONS OBTAINABLE BY THIS PROCESS, AND THEIR USE FOR THE PRODUCTION OF COATINGS

摘要

ABSTRACT OF THE DISCLOSUREThis invention relates to a new process forthe preparation of storage stable aqueous dispersionsor solutions of cross-linkable polyurethane polyureascontaining heat activated cross-linking agents, inwhich mixtures of hydrophilically modified prepolymerscontaining isocyanate groups, hydrophobic polyisocya-nates which contain blocked isocyanate groups and areneither soluble nor dispersible in water, and compoundscontaining at the most one free aminic or hydrazinicprimary or secondary amino group and at least oneblocked group which under the influence of water formsa free aminic or hydrazinic primary or secondary aminogroup and a total of at least two such amino groups areprepared in the absence of water and then mixed withwater, and it also relates to the aqueous dispersionsor solutions obtained by this process and to their usefor the production of coatings on heat-resistantsubstrates.