Methods for reducing aldehyde emissions in polyurethane foams

Patent metadata

Field	Value
Publication number	US-2021309789-A1
Application number	US-201817262818-A
Country	US
Kind code	A1
Filing date	Aug 2, 2018
Priority date	Aug 2, 2018
Publication date	Oct 7, 2021
Grant date	—

Abstract

Polyurethane foams are made by curing a reaction mixture that contains an aromatic polyisocyanate, at least one isocyanate-reactive material having an average functionality of at least 2 and an equivalent weight of at least 200 per isocyanate-reactive group, at least one blowing agent, at least one surfactant, at least one catalyst, and certain aldehyde-suppressing additives. Foams so produced emit low levels of formaldehyde, acetaldehyde and propionaldehyde.

First claim

1 . A process for producing a polyurethane foam comprising forming a reaction mixture that contains an aromatic polyisocyanate, at least one isocyanate-reactive material having an average functionality of at least 2 and an equivalent weight of at least 200 per isocyanate-reactive group, at least one blowing agent, at least one surfactant and at least one catalyst, and curing the reaction mixture in the presence of (i) at least one hindered amine represented by structure I:

wherein Y is hydrogen, alkyl, or →O, R 1 and R 3 each are independently alkyl, aryl-substituted alkyl, aryl or alkyl-substituted aryl; R 2 and R 4 each are independently hydrogen, alkyl, aryl-substituted alkyl, aryl or alkyl-substituted aryl; m is at least 1, preferably 1 or 2, A is H, —OH, —NH 2 , alkyl or a chemical bond when m is 1 and chemical bond or a linking group when m is 2 or more, and Z is —CH 2 — or a chemical bond, and ii) at least one compound represented by structure II:

wherein R 6 and R 7 are independently hydrogen, alkyl, aryl-substituted alkyl, aryl or alkyl-substituted aryl, and R 8 is:

wherein R 9 , R 10 and R 11 , are each independently hydrogen, alkyl, aryl-substituted alkyl, aryl or alkyl-substituted aryl with the proviso that R 9 and R 10 , and/or R 10 and R 11 may form rings.

2 . A method for reducing aldehyde emissions from a polyurethane foam, comprising: a) combining (i) at least one hindered amine represented by structure I:

wherein Y is hydrogen, alkyl, or →O, R 1 and R 3 each are independently alkyl, aryl-substituted alkyl, aryl or alkyl-substituted aryl; R 2 and R 4 each are independently hydrogen, alkyl, aryl-substituted alkyl, aryl or alkyl-substituted aryl; m is at least 1, preferably 1 or 2, A is H, —OH, —NH 2 , alkyl or a chemical bond when m is 1 and chemical bond or a linking group when m is 2 or more, and Z is —CH 2 — or a chemical bond, and ii) at least one compound represented by structure II:

wherein R 6 and R 7 are independently hydrogen, alkyl, aryl-substituted alkyl, aryl or alkyl-substituted aryl, and R 8 is:

wherein R 9 , R 10 and R 11 , are each independently hydrogen, alkyl, aryl-substituted alkyl, aryl or alkyl-substituted aryl with the proviso that R 9 and R 10 , and/or R 10 and R 11 may form rings,
with at least one isocyanate-reactive material having an average functionality of at least 2 and an equivalent weight of at least 200 per isocyanate-reactive group to form a mixture and then b) combining the mixture from step a) with at least one organic polyisocyanate and curing the resulting combination in the presence of at least one blowing agent, at least one surfactant and at least one catalyst to form a polyurethane foam.

3 . The process of claim 1 wherein R 1 , R 2 , R 3 and R 4 are each independently C1-C4 alkyl.

4 . The process of claim 3 wherein m is 1 and A is hydrogen, hydroxyl, —NH 2 or alkyl.

5 . The process of claim 3 wherein m is 2 or more and A is —O—, —NH—, alkylene, arylene, aryl-substituted alkylene, aryl-substituted alkylene, —NH—C(O)—(CH 2 ) o —C(O)—NH— where 0 is 1 to 20, or —O—C(O)—(CH 2 ) o —C(O)—O— where o is 1 to 20.

6 . The process of claim 1 wherein the structure I compound is selected from one or more compounds represented by any of structures III-XII:

7 . The process of claim 1 wherein R 6 is C1-C4 alkyl and R 7 is hydrogen or C1-C4 alkyl.

8 . The process of claim 1 wherein the structure II compound is a compound represented by any of structures XIII-XVIII:

9 . The method of claim 1 wherein the compound represented by structure I is present in an amount of from 0.02 to 0.25 parts by weight per 100 parts by weight of the at least one isocyanate reactive compound having at least two isocyanate-reactive groups per molecule and an equivalent weight of at least 200 per isocyanate-reactive group.

10 . The method of claim 1 wherein the compound represented by structure II is present in an amount of from 0.02 to 0.25 parts by weight per 100 parts by weight of the at least one isocyanate reactive compound having at least two isocyanate-reactive groups per molecule and an equivalent weight of at least 200 per isocyanate-reactive group.

11 . The method of claim 1 wherein the reaction mixture is cured in the presence of an antioxidant.

12 . The method of claim 11 wherein the antioxidant is a phenolic compound.

13 . The method of claim 12 wherein the antioxidant is present in an amount of 0.2 to 1.5 parts by weight per 100 parts by weight of the at least one isocyanate reactive compound having at least two isocyanate-reactive groups per molecule and an equivalent weight of at least 200 per isocyanate-reactive group.

14 . A polyurethane foam made in accordance with the process of claim 1 .

Assignees

• Dow Global Technologies Llc

Inventors

• Tang Zhengming
• Chen Hongliang
• Zou Jian
• Feng Shaoguang
• Zhang Degang
• Zhang Ping

Classifications

• C08J9/125

  Water, e.g. hydrated salts · CPC title

• C08G18/4072

  Mixtures of compounds of group C08G18/63 with other macromolecular compounds · CPC title

• C08K5/07

  Aldehydes; Ketones · CPC title

• C08G18/282

  Alkanols, cycloalkanols or arylalkanols including terpenealcohols · CPC title

• C08G18/76

  aromatic · CPC title