US 12,441,835 B2
Method for producing polyester polyol
Te-Chao Liao, Taipei (TW); Han-Ching Hsu, Taipei (TW); and Chen-Wei Chang, Taipei (TW)
Assigned to NAN YA PLASTICS CORPORATION, Taipei (TW)
Filed by NAN YA PLASTICS CORPORATION, Taipei (TW)
Filed on Nov. 30, 2022, as Appl. No. 18/071,807.
Claims priority of application No. 111138927 (TW), filed on Oct. 14, 2022.
Prior Publication US 2024/0124643 A1, Apr. 18, 2024
Int. Cl. C08G 63/40 (2006.01); C08G 63/16 (2006.01); C08G 63/183 (2006.01); C08G 63/78 (2006.01); C08G 63/80 (2006.01); C08G 63/85 (2006.01)
CPC C08G 63/40 (2013.01) [C08G 63/183 (2013.01); C08G 63/85 (2013.01); C08G 63/16 (2013.01); C08G 63/78 (2013.01); C08G 63/80 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for producing a polyester polyol, comprising:
feeding a first antioxidant and a raw material reactant that includes a polyacid and a polyol into a reactor, and subjecting the polyacid and the polyol to an esterification reaction in the reactor, so as to form an oligomer; wherein the first antioxidant is a polymeric antioxidant having a molecular weight of not less than 1,000 g/mol; and
performing a prepolymerization reaction on the oligomer in the reactor, so as to obtain a prepolymerization reactant;
wherein, during the prepolymerization reaction, the method includes sampling and monitoring an acid value of the prepolymerization reactant; wherein, when the acid value of the prepolymerization reactant reaches a first acid value, the method includes adding an esterification reaction catalyst to the prepolymerization reactant, so as to start a polycondensation reaction and generate a polycondensation reactant that contains the polyester polyol; wherein the first acid value is between 15 mg KOH/g and 35 mg KOH/g;
wherein, during the polycondensation reaction, the method includes sampling and monitoring an acid value of the polycondensation reactant; wherein, when the acid value of the polycondensation reactant reaches a second acid value, the polycondensation reaction is terminated; wherein the second acid value is not greater than 0.3 mg KOH/g.