| abstract |
A polyurethane polyanhydride oligomer is disclosed as well as a process for its preparation. The process involves the following steps: (a) reacting a hydroxyl functional 2,4-dienoate ester with a polyisocyanate under conditions sufficient to react essentially all of the isocyanate groups to form a polyurethane polyene; and (b) reacting by Diels Alder addition the unsaturated double bonds of the polyurethane polyene with an unsaturated polycarboxylic acid anhydride containing material. Also disclosed is a curable composition containing hydroxyl functional material and the aforedescribed polyurethane polyanhydride oligomer. |