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

This invention relates to a new process for the preparation of storage stable aqueous dispersions or solutions of cross-linkable polyurethane polyureas containing heat activated cross-linking agents, in which mixtures of hydrophilically modified prepolymers containing isocyanate groups, hydrophobic polyisocyanates which contain blocked isocyanate groups and are neither soluble nor dispersible in water, and compounds containing at the most one free aminic or hydrazinic primary or secondary amino group and at least one blocked group which under the influence of water forms a free aminic or hydrazinic primary or secondary amino group and a total of at least two such amino groups are prepared in the absence of water and then mixed with water, and it also relates to the aqueous dispersions or solutions obtained by this process and to their use for the production of coatings on heat-resistant substrates.