Title: AQUEOUS DISPERSIONS OF POLYURETHANE AND NANOPARTICLES

 Number/Link: WO2013/059106

Applicant/Assignee: Bayer

Publication date: 25-04-2013

“Gist”: Amino-functional inorganic nanoparticles are reacted with residual isocyanate groups of a PUD-forming polyurethane prepolymer and subsequently dispersed in water.

Why it is interesting: A water-dispersible polyurethane prepolymer is made from isocyanate, polyol and chain extender in which polyol and/or chain extender comprise ionic or potentially ionic groups.  The prepolymer is produced with a surplus of isocyanate which is subsequently reacted with amino-functional inorganic nanoparticles.  The nanoparticles consist of e.g. metal oxides which were reacted with a “bridging compound” comprising an isocyanate-reactive group (NH2 or OH) and a particle-reactive group e.g. a halogen or silane group. The polyurethane with covalently integrated nanoparticles can then be dispersed in water using a known process.  The resulting PUD has a high shelf-life and can be used in coatings, adhesives, films etc. with improved properties.

Polyurethane dispersion and film made from it. (Wikimedia)