Preparation and Properties of Aqueous Dispersible Polyurethane
Charoen Chinwanitcharoen, Toshiro Yamada, Shigeyoshi Kanoh, Shunichi Hayashi
Dept. of Chemistry & Chem. Eng., Kanazawa University
Japan

Keywords: polyurethane, waterborne, internal emulsifier

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Conventional organic solvent-based polyurethane (PU) should be regulated by an environmental requirement on reducing the discharge of toxic volatile organic solvents, such as N,N-dimethylformamide and N,N-dimethylacetamide into the atmosphere. To meet such environmental regulations, the realization of aqueous dispersible PU has been strongly awaited. Herein, we report the preparation and properties of an aqueous dispersible PU. An anionizable PU prepolymer was prepared by the polyaddition of an OH-terminated oligoester and dimethylol propionic acid with an excess of diisocyante in a minimized amount of N-methyl-2-pyrrolidinone. The NCO-terminated prepolymer was chain-extended with ethylene glycol. The pendant carboxyl groups incorporated into the PU postpolymer were neutralized with triethylamine. Phase inversion was carried out by addition of water into the anionized PU. The resulting aqueous PU dispersion has shelf life more than 6 months storage in room temperature. Effect of internal emulsifier content, molecular weight of oligoester and NCO/OH ratio also were investigated.