Reducing aldehyde emissions from flexible foams

Title: POLYURETHANE FOAMS WITH DECREASED ALDEHYDE EMISSIONS, A PROCESS FOR PREPARING THESE FOAMS AND A METHOD FOR DECREASING ALDEHYDE EMISSIONS IN POLYURETHANE FOAMS

 Number/Link: WO2013116092

Applicant/Assignee: Bayer

Publication date: 8-08-2013

Gist”: Use of small amounts of hexamethylenediisocyanate trimer or small amounts of “PHD” polyols result in reduced aldehyde emissions from flex foams.

Why it is interesting: Reduction of VOC emissions and especially emissions of formaldehyde and acetaldehyde are an important issue for the polyurethane flexible foam industry, especially for bedding and automotive applications. This invention teaches two “tricks” to help solve the problem.  To a (preferably) TDI-based flex foam formulation which comprises at least one SAN or PIPA filled polyol, 0.5-3 pbw of trimerized hexamethylene diisocyanate is added on 100 pbw of the isocyanate.  Alternatively 2-3 pbw of PHD polyol is added on 100 pbw of the iso-reactive component. In the art “PHD polyol” usually stands for a polyurea ‘filled’ polyol (polyharnstoff dispersion), but in this case it stands for polyhydrazodicarnbonamide filled polyols. These PHD polyols are prepared by reacting a hydrazine with an isocyanate (pref TDI80) in a base polyol, so they are actually a subset of ‘conventional’ PHD dispersions.  The patent application is a bit confusing in this respect.

Hydroazodicarbonamide

Hydrazodicarbonamide

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2 Comments

  1. PAUL MENGNJOH

     /  August 14, 2013

    You are right to say this is an interesting development.Is it possible to add vannila in the mix to combat the smell. I am not sure if vannila can prevent the foaming reaction leading to foam collapse.

    Reply
  2. Hi Paul, I am not familiar with vanilla, but it is an extract that contains many different compounds, some of which are oily and (probably) some which act as strong surfactants, so it might well be that you end up with collapse or closed and shrinking foam. You could consider using a synthetic fragrant instead. However my experience is, that it is better to try to reduce that smell rather than cover it up with another one – this can really backfire. Have you seen this post of mine: https://purpatents.com/2012/11/13/smell-free-flexible-polyurethane-foams-at-last/ This would be a real solution but you could run into freedom-to act problems. I could find that out for you if you want.

    Reply

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