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

US4543144A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Wilhelm Thoma · Leverkusen, DE
• Klaus Nachtkamp · Cologne, DE
• Walter Schroer · Leverkusen, DE
• Rolf Langel · Leverkusen, DE

Key dates

• Filing date: Apr 11, 1984
• Grant date: Sep 24, 1985
• Expiry date: Apr 11, 2004

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S428/904
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

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.