Aqueous polyurethane compositions containing crosslinking agents and their use for heat-active one-coat reverse coating

Abstract

This invention relates to compositions of aqueous polyurethane dispersions containing polyurethanes having lateral OH-groups, optionally in admixture with PU-dispersions without any lateral OH-groups, which contain a combination of formaldehyde resins and blocked polyisocyanates as crosslinking agent and, optionally handle-improving agents, silicones and standard additives. The present invention also relates to the use of these compositions for the production of light coatings by the heat-activated, one-coat reverse coating process, in which the PU-composition is applied to a temporary support and dried, after which the (textile) substrate is laminated onto the dry polyurethane film at elevated temperature and pressure and the polyurethane laminate formed is subsequently crosslinked at a relatively high temperature. Mixed crosslinking with formaldehyde resins plus blocked polyisocyanates makes it possible to obtain coatings characterized by outstanding substrate adhesion and wet strength values.

Dependencies are inferred from the claim text.