Isocyanate-Free Polyaminal-Polyurethane Foams


 Number/Link: WO2018/005142

Applicant/Assignee:  Dow

Publication date: 4 January 2018

Gist”: Polyaldehydes are reacted with polycarbamates in the presence of an acid catalyst, a metal oxide powder and a blowing agent.

Why it is interesting: According to this invention hydrolytically-stable foams can be prepared from a low molecular weight difunctional aldehyde and a polycarbamate with a functionality of about 3.5 to 4 and an equivalent weight of about 200 to 300, in the presence of a blowing agent and a protic acid as catalyst. Surprisingly the foams are rendered hydrolytically stable by the incorporation of a metal oxide powder with a specific particle size. In the examples polycarbamates are prepared by capping high functionality polyols with methylcarbamate and are then reacted with 1,4-cyclohexanedicarboxaldehyde together with p-toluensulfonic acid as catalyst, HFC245fa as blowing agent and MgO powder. The foams show densities of 130-170 kg/m³ and are said to be useful as sealants.



Sequence-Defined Polyurethanes for Information Storage


 Number/Link: WO2017/194694

Applicant/Assignee:  Centre National de la Recherche

Publication date: 16 November 2017

Gist”: Stepwise immobilized polymer synthesis is used to make polyurethane having a predefined sequence of monomers

Why it is interesting: The invention is about monodisperse polyurethanes consisting of a well-defined sequence of monomers having various chain lengths and side groups – not unlike proteins or nucleic acids. In a first step a solid support (e.g. polystyrene beads) which bears a cleavable tether molecule is reacted with N,N’-disuccinimidylcarbonate and in a second step with an aminoalcohol like 5-amino-1-pentanol. Steps 1 and 2 are then repeated using the same or a different aminoalcohol. Finally the tether is cleaved from the support.  If 2 different aminoalcohols are used, a binary code can be encoded in the molecule which can later be read using a sequencing technique. The polyurethanes are said to be useful in anti-counterfeiting technologies.


Reaction sequence according to the invention

Non-Isocyanate Polyurethane Flexible Foams



Applicant/Assignee: Faurecia

Publication Date: 3 august 2017

“Gist”: Flex foams from a blend of two polyfunctional cyclocarbonates, a polyamine and HFC blowing agent.

Why it is interesting: While non-isocyanate polyurethanes are well known by now, examples of NIPU foams, especially flexible foams are rare. According to this case NIPU foams ‘having good resilience and low density’ can be prepared by reacting two polyfunctional carbonates A and B with a polyamine in the presence of a blowing agent and a catalyst. Cyclocarbonate A is (pref) trimethylolpropaneglycidylether carbonate and B is a polyetherpolyol with the OH groups replaced by glycidylcarbonate groups, for example an alkoxyalated trimethylolpropaneglycidylether carbonate. The polyamine is e.g. 1,6 diaminohexane.  The ratio A:B is preferably about 60:40.  In the examples no value for the resilience is given (but my guess based on the Tg is that it is probably not very high) and the lowest moulded density achieved is 140 kg/m³. So still a long way to go..

Glycidylether carbonate of alkoxylkated trimethylolpropane

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

PU Rigid Foams from Biomass Proteins



Applicant/Assignee:  Inventors

Publication date: 16-07-2015

Gist”: Soy bean proteins are hydrolysed and reacted with diamines and cylocarbonates to produce “rigid” polyols.

Why it is interesting: During recent years a lot of research has been done on the use of renewable raw materials in polyurethanes.  Most of this research was on the use of natural oils despite the fact that the availability of biomass proteins is much higher. Soybeans for example contain about twice as much protein (about 38% w/w) than oil (18%) and the price is about half that of the oil. According to this invention soybean proteins are hydrolysed into amino acids which are then reacted with ethylene diamine to make amine-ended monomers.  These monomers are reacted with a cyclocarbonate (ethylene carbonate or glycerol carbonate) resulting in a mixture of hydroxyurethane oligomers. The mixture is a low viscous liquid with high hydroxyl value useful for the production of rigid foams.

Reaction sequence according to the invention

Reaction sequence according to the invention