PU Flexible Foams with Reduced Acetaldehyde Emissions

Title: METHOD FOR THE REDUCTION OF ALDEHYDE EMISSION IN POLYURETHANE FOAM

Number/Link: WO2017/134296

Applicant/Assignee: Huntsman

Publication Date: 10 August 2017

“Gist”: Cyanoacetamide is used as aldehyde scavenger

Why it is interesting: Reduction of aldehyde emissions from (especially flexible) polyurethane foams remains an important issue and has already been discussed a number of times on this blog. According to this case the use of (pref) 0.05 to 0.5 pbw of cyanoacetamide in a flexible foam formulation will reduce the emission of formaldehyde, acetaldehyde, propionaldehyde, and possibly of higher aldehydes as well.
While an interesting compound, the use of cyanoacetamide in polyurethanes is not new and the effect is hardly surprising.

Cyanoacetamide

 

Polycarbonate PU Foams with Reduced VOC Emissions

Title: POLYURETHANE FOAMS BASED ON POLYETHER CARBONATE POLYOLS

Number/Link: WO2017/085201 (German)

Applicant/Assignee: Covestro

Publication Date: 26-may-2017

“Gist”: Use of urea reduces the formation of propylenecarbonate from polycarbonate polyols

Why it is interesting: Covestry is betting heavily on polyethercarbonate polyols for use in polyurethane foams, using the carbon-negative footprint as a selling point. The use of polyethercarbonate polyols in PU foams can, however, result in the formation of propylenecarbonate resulting from a retro reaction promoted by conventional amine catalysts. Propylenecarbonate will contribute to the total VOC emissions of foams and other materials. According to this invention, the retro reaction can -surprisingly- be prevented or reduced by using urea or urea-derivatives in the foam formulation. In the examples urea and dimethylaminopropylurea are used together with a tin catalyst,  polyethercarbonate polyols and TDI to produce flexible foams with reduced propylenecarbonate content.

Propylenecarbonate

 

 

Polyurethanes with Reduced Aldehyde Emissions

Title: POLYURETHANES HAVING REDUCED ALDEHYDE EMISSION

 Number/Link:WO2015/082316 (German)

Applicant/Assignee: BASF

Publication date: 11-06-2015

Gist”: Use of CH-acidic compounds as aldehyde scavengers

Why it is interesting: Reducing VOC emissions, and especially aldehyde emissions, from polyurethane systems remains an important research topic and has been discussed before on this blog (see e.g.  here and here). To reduce aldehyde emissions, scavenger molecules are used which are often amines or hydrazine compounds.  In this invention however the aldehyde scavenger is a CH-acidic compound of the form R-CH2-R’ in which R and R’ are electron-withdrawing groups. The R-groups can be iso-reactive and the molecule can (preferably) contain more than one acidic CH2 group, like e.g. trimethylolpropane triacetoacetate. Other examples are N,N-dimethylacetoacetamide and dimethyl 1,3-acetonedicarboxylate. The compounds are used in an amount of 0.5 to 1 pphp, are said to have advantages over the prior art like less or no catalytic activity and do not lead to extra emissions.

Trimethylolpropane triacetoacetate

Trimethylolpropane triacetoacetate

Reducing Aldehyde Emissions from Polyurethane Foams

Title: USE OF PENTAETHYLENE HEXAMINE IN THE PRODUCTION OF POLYURETHANE SYSTEMS

 Number/Link: WO2015/071065 (German)

Applicant/Assignee: Evonik

Publication date: 21-05-2015

Gist”: Use of pentaethylenehexamine to reduce aldehyde emissions

Why it is interesting: As mentioned in previous posts, the reduction of formaldehyde and acetaldehyde emissions from polyurethane foams remains a pressing environmental issue. According to this patent application the problem can be solved by adding some (1 pphp in the examples) of pentaethylene hexamine to the polyol formulation. The polyamine will act as a formaldehyde scavenger and has some advantages over the prior art.  In the related case WO2015/071063, the pentaethylene hexamine is first reacted with guanidine chloride before being added to the formulation.

Pentaethylene hexamine

Pentaethylene hexamine