Abstract: A polyurethane dispersion containing the reaction product of a polyurethane prepolymer and water are shear, shelf, temperature, pH and electrolyte stable. The amount of the reaction product in the dispersion may be as high as 60 weight percent. The prepolymer may be the reaction product of a polyisocyanate and a hydrophilic alkylene oxide polyol or polyamine having a molecular weight of between 800 and 1,500 and an active-hydrogen containing material, such as a polyol, and optionally, a surfactant. The hydrophilic alkylene oxide polyol or polyamine is present in an amount sufficient to reduce the interfacial tension of the prepolymer to less than or equal to 10 dynes/cm. The amount of ethylene oxide in the prepolymer is between from about 0.5 to about 5.5 weight percent. The water solubility of the high molecular weight active-hydrogen containing material is typically less than about 10.0 g per 100 g of water.

Abstract: A rigid thermoplastic polyurethane with improved melt strength can be prepared by deactivating the catalyst for the polymer subsequent to the onset of urethane bond formation. Catalyst deactivation is accomplished either with a latent deactivator for the catalyst, or an active deactivator. The further addition of a crosslinker to the reaction mixture can provide an even greater improvement of melt strength.