A selective catalyst for two-component waterborne polyurethane coatings

A new way of creating cellular polyurethane materials: NIPU foams

“…However, polyol/isocyanate (gelling) and isocyanate/water (blowing) reactions are competing reactions [9] (Scheme 1). The reaction between polyol and isocyanate forms urethane linkages, while reaction between isocyanate and water yields amine and carbon dioxide allowing for foaming in the preparation of PU foams.…”

Room temperature flexible isocyanate-free polyurethane foams

“…Yet, the preparation of classic polyurethane foam is carried out at room temperature, adding water to the polyol/isocyanate mixture. The reaction between isocyanate and water yields amine and carbon dioxide that allows foaming [49]. As the gelling reaction (polyol/isocyanate), the foaming reaction takes place at room temperature.…”

Advances in Catalysis for Organic Coatings

“…Zirconium catalysts are also selective [10] in catalyzing the isocyanate-hydroxyl reaction over the water reaction and have found applications as catalysts for selected waterborne two component tions. Amino formaldehyde resins require acid catalysis for cure.…”