Method for producing polyester polyol

Patent metadata

Field	Value
Publication number	US-12441835-B2
Application number	US-202218071807-A
Country	US
Kind code	B2
Filing date	Nov 30, 2022
Priority date	Oct 14, 2022
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

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 the prepolymerization reaction, the method includes sampling and monitoring an acid value of the prepolymerization reactant. When the acid value of the prepolymerization reactant reaches a first acid value, an esterification reaction catalyst is added to the prepolymerization reactant for carrying out a polycondensation reaction and generating a polycondensation reactant that contains the polyester polyol. During the polycondensation reaction, the method includes sampling and monitoring an acid value of the polycondensation reactant. When the acid value of the polycondensation reactant reaches a second acid value, the polycondensation reaction is terminated.

First claim

What is claimed is:

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.

2. The method according to claim 1 , further comprising:
adding, after the acid value of the polycondensation reactant reaches the second acid value, an anti-hydrolysis agent and a second antioxidant to the polycondensation reactant, wherein the anti-hydrolysis agent is a monomeric anti-hydrolysis agent or a polymeric anti-hydrolysis agent, and an added amount of the anti-hydrolysis agent is between 1 times and 8 times an acid value equivalent of the polycondensation reactant; wherein the second antioxidant is a typical antioxidant having a molecular weight of not greater than 1,000 g/mol, and an added amount of the second antioxidant is between 50 ppm and 5,000 ppm.

3. The method according to claim 1 , wherein, in the esterification reaction, the polyacid and the polyol carry out an oligomerization reaction at a first reaction temperature and at a first reaction pressure; wherein the first reaction temperature is between 140° C. and 230° C., and the first reaction pressure is between 740 torr and 780 torr.

4. The method according to claim 3 , wherein the prepolymerization reaction is carried out under conditions that gas pumping and pressure reduction are performed on the reactor by a vacuum pump, such that a gas pressure in the reactor is reduced from the first reaction pressure to a second reaction pressure; wherein the prepolymerization reaction is carried out by heating to a second reaction temperature; wherein the second reaction temperature is between 200° C. and 250° C., and the second reaction pressure is between 20 torr and 70 torr.

5. The method according to claim 1 , wherein a stirrer is disposed in the reactor to stir the polyacid and the polyol; wherein a top portion of the reactor is in spatial communication with a separation column, a condensing pipe that is in communication with an inside of the reactor is disposed at a tower top of the separation column, and a separation column top temperature of the tower top of the separation column is controlled to be within a temperature range between 95° C. and 105° C., such that a separated substance that is separated by the separation column and refluxed from the tower top is controlled to have a temperature within said temperature range.

6. The method according to claim 1 , wherein, when an esterification rate of the esterification reaction is between 80% and 90%, the esterification reaction is terminated to complete preparation of the oligomer, and the oligomer is prepared to enter the subsequent prepolymerization reaction.

7. The method according to claim 2 , wherein the polycondensation reaction further includes performing a dealcoholization operation on the polycondensation reactant at a dealcoholization pressure between 5 torr and 30 torr, so as to remove redundant polyol reaction monomers in the polycondensation reactant.

8. The method according to claim 2 , wherein the anti-hydrolysis agent and the second antioxidant are added under a condition that the polycondensation reactant is reduced to a cooling temperature that is between 90° C. and 120° C.

9. The method according to claim 2 , wherein the anti-hydrolysis agent is added to the polycondensation reactant before the second antioxidant is added to the polycondensation reactant.

10. The method according to claim 2 , wherein the anti-hydrolysis agent includes a monomeric anti-hydrolysis agent that is side-modified with a long carbon chain, and the long carbon chain has a carbon chain length between C8 and C18.

Assignees

• Nan Ya Plastics Corp

Inventors

• Liao Te-Chao
• Hsu Han-Ching
• Chang Chen-Wei

Classifications

• C08G63/80

  Solid-state polycondensation · CPC title

• C08G63/16 Primary

  Dicarboxylic acids and dihydroxy compounds · CPC title

• C08G63/78

  Preparation processes · CPC title

• C08G63/183

  Terephthalic acids · CPC title

• C08G63/85

  Germanium, tin, lead, arsenic, antimony, bismuth, titanium, zirconium, hafnium, vanadium, niobium, tantalum, or compounds thereof {(C08G63/823 takes precedence)} · CPC title