The Dow Chemical Company

Michael J Van Eyck

Kenneth A Burdett

Laurence I Peterson

The biuret polyisocyanates correspond to the formula ##STR1## wherein R is --CH.sub.2 CH.sub.2 --O--CH.sub.2 CH.sub.2 -- and X is hydrogen or --C(O)--NX--R--NCO, and they have not more than six isocyanato groups per molecule. These compounds are prepared by reacting bis(2-isocyanatoethyl)ether with water in a mole ratio of at least 3 moles of diisocyanate per mole of water. The biuret polyisocyanates are particularly useful in the preparation of polyurethanes.

Biuret polyisocyanates

Compounds of the formula ##STR1## wherein --R-- is di-, tri- or tetramethylene which may bear from 1 to 8 C.sub.1 -C.sub.3 alkyl substituents, and a process for their preparation wherein a reactant of the formula ##STR2## is contacted, at reaction temperature, with COCl.sub.2. For example, 2-imidazolidone is contacted with phosgene to form N,N'-bis(carbonyl chloride)-2-imidazolidone. The compounds may be condensed with polyols, polythiols or polyamines to form useful resins or pyrolyzed to give alkylene diisocyanates.

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Midland, MI, United States of America

Michael J Van Eyck