Natural Oil Polyols for Waterborne Polyurethane Dispersions

By John Argyropoulos, Bedri Erdem, Debkumar Bhattacharjee, Paul Foley, Kumar Nanjundiah

In recent decades, aqueous polymeric dispersions have emerged to replace solvent-based products in many applications such as coatings, foams, sealants, and adhesives. Not only do these systems result in the preparation of products with mitigated environmental health and safety (EH&S) issues ( solvents, monomers, etc.), but the products have improved properties and performance.

Aqueous polyurethane dispersions (PUDs) are an important class of poly­meric dispersions and are often produced by the emulsification of an iso­cyanate-terminated polyurethane prepolymer in water via the use of vigor­ous shear and mixing. The type and amount of shear and surface active agents employed are very critical in obtaining PUDs with submicron particle size and colloidal stability. The batch process, which is the most commonly utilized process to produce PUDs, relies heavily on the incorporation of ionic molecules such as carboxylates, sulfonates, or tertiary ammonium salts into the polymer backbone. These groups impart water dispersibility to the resin upon neutralization and help minimize the requirement of shear in a batch process.