Classic PU Patent of the Month: Non-Isocyanate Polyhydroxyurethanes by Dow (1957)

Title: Polyhydroxyurethanes

 Number/Link: US3084140

Applicant/Assignee: Dow

Publication date: 2-04-1963

Gist”: bis-cyclocarbonates are reacted with aliphatic polyamines

Why it is interesting: Non-isocyanate polyurethanes (NIPU) are still gaining in popularity – at least in the patent and science literature. The chemistries to make NIPU are far from new as discussed in a previous ‘classic patent of the month’ on this blog.  The most common route to NIPU is by reacting cyclocarbonates with amines resulting in hydroxyurethanes, as was first dicussed in this patent. The intent of the invention was, actually, not to avoid the use of isocyanates but to make hydroxy-group containing polyurethanes which were said to be ‘highly desirable’:  the OH groups can act as points for crosslinking, make the resin more hydrophilic and compatible with certain materials etc.

Preparation of polyhydroxyurethanes according to the invention

Preparation of polyhydroxyurethanes according to the invention


Polyols from Urethane Alcohols


 Number/Link: WO2015075057

Applicant/Assignee: Bayer

Publication date: 28-05-2015

Gist”: Urethane alcohols prepared from cyclocarbonates are used as starters for polyether polyols

Why it is interesting: Urethane diols are prepared by reacting cyclic carbonates like ethylene- or propylene carbonate with an alkanolamine like e.g. ethanolamine. The alcohols are then further reacted with propylene oxide and/or ethylene oxide to make polyether polyols, useful for the production of flexible foams a.o.  No comparison of the properties of these polyols (or of the resulting foams), with ‘conventional’ polyether polyols, is given. The only advantage (at least for Bayer) being that the polyols are partly based on cyclocarbonates which are by-products of the polycarbonate polyol production.

A Urethane Alcohol

A Urethane Alcohol

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