| abstract |
A hyperbranched polyester polyol macromolecule, having a plurality of both embedded and exterior hydroxyl groups thereon, may be synthesized in a 5 polymerization reaction having several steps. The hyperbranched polyol includes a central nucleus, a first chain extension, an inten-nediate substituent and a second chain extension. The central nucleus is a hydrocarbon structure with a plurality of oxygen atoms. The first chain extender is attached to the central nucleus and includes a carboxylic ester group and a plurality of hydroxyl groups. The intermediate substituent is attached to the first chain extender, and is a polyfunctional carboxylic acid or anhydride thereof. The preferred intermediate substituent is a cyclic compound. The second chain extension is attached to the inten-nediate substituent. The preferred second chain extension includes a glycidyl ester or epoxy. Methods of making a hyperbranched polyester polyol are also disclosed. Coating compositions in which the hyperbranched polyol is reacted with an aminoplast or with an isocyanate are also encompassed by the invention. |