Patent ID: 8790763

Claim:
A method to reduce the tendency of a thermoplastic polyurethane polymer to bloom comprising making the thermoplastic polyurethane by the reaction of: (1) a hydroxyl terminated polyester intermediate, wherein the hydroxyl terminated intermediate is comprised of repeat units that are derived from 1,3-propylene glycol and adipic acid, and said hydroxyl terminated intermediate has a number average molecular weight which is within the range of 500 to 10,000 Daltons; (2) a diisocyanate of 4,4′-methylene bis-(phenyl isocyanate); and (3) a glycol chain extender, wherein 1,3-propylene glycol represents 70 to 95 weight percent of the glycol component used to synthesize the hydroxyl terminated polyester intermediate, and wherein the thermoplastic polyurethane polymer has a hardness ranging from Shore A 85 to Shore D 80.