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US 10,450,398 B2Granted
High functionality polyesters and coatings comprising the same
AssigneePPG Industries Ohio, Inc.
InventorsKam Lun Lock, Richard Woods, Nigel Francis Masters
Life of this patent
Estimating the term…
Abstract
A polyester prepared by free radical polymerization of an unsaturated polyester prepolymer, wherein the polymerization occurs primarily by reaction of the unsaturation of said prepolymer is disclosed. Coatings comprising the same are also disclosed, as are substrates coated at least in part with such coating.
Claims10
A process for preparing an ungelled crosslinkable polyester resin comprising:
- (a) reacting a polycarboxylic acid with a polyol to form an unsaturated polyester prepolymer in which the unsaturation is along the backbone of the unsaturated polyester prepolymer and wherein the unsaturated polyester prepolymer has terminal acid and/or hydroxyl functional groups, a hydroxyl value ranging from 2 to 500 mg KOH/gm and/or an acid value ranging from 1 to 400 mg KOH/gm;
- and
- (b) subjecting the unsaturated polyester prepolymer to thermally induced free radical polymerization via the points of unsaturation along the unsaturated polyester prepolymer backbone to form the ungelled crosslinkable polyester resin that has a higher weight average molecular weight than the unsaturated polyester prepolymer such that the weight average molecular weight ratio of the ungelled crosslinkable polyester resin to the unsaturated polyester prepolymer is at least 1.2 and the hydroxyl value and the acid value of the ungelled crosslinkable polyester resin is in the same range as those of the prepolymer.
Dependencies are inferred from the claim text.