ALEXANDRIA, Va., Oct. 21 -- United States Patent no. 12,441,835, issued on Oct. 14, was assigned to NAN YA PLASTICS Corp. (Taipei, Taiwan).
"Method for producing polyester polyol" was invented by Te-Chao Liao (Taipei, Taiwan), Han-Ching Hsu (Taipei, Taiwan) and Chen-Wei Chang (Taipei, Taiwan).
According to the abstract* released by the U.S. Patent & Trademark Office: "A method for producing a polyester polyol is provided, which includes: feeding a first antioxidant and a raw material reactant that includes a polyacid and a polyol into a reactor; subjecting the polyacid and the polyol to an esterification reaction to form an oligomer; and performing a prepolymerization reaction on the oligomer to obtain a prepolymerization reactant. During...