More Isocyanate-Free Polyurethanes

Title: FUNCTIONAL POLYURETHANE PREPOLYMER, METHOD OF PREPARING POLYURETHANE BY USING THE SAME, AND APPLICATION METHOD THEREOF

 Number/Link: US2013004677

Applicant/Assignee: AMKANG UNIVERSITY (TAIWAN)

Publication date: 3-01-2013

“Gist”: Bis(cyclic carbonate) compounds are produced by reacting  bisphenol-A diglycidylether with CO2.  These are then reacted with diamine oligomers (EO-PO and/or PDMS) to produce amine ended β-hydroxy-PU prepolymers which in turn are capped with acrylates to make a UV curable system useful for coating fabrics.

Why it is interesting: The materials are produced without “toxic” isocyanates and “harmful” phosgene (sic), but still need “harmful” amines and solvents. If made solvent-free, however, systems like this could make a lot of sense in e.g. synthetic leather production (IMHO).

isofreePU

Isocyanate-free PU from BPA-based cyclic carbonates and amines

Polyurethane Elastomers with Very Low Glass Transition Temperature

Title: Low temperature segmented copolymer compositions and methods

 Number/Link: US8334356

Applicant/Assignee: Boeing

Publication date: 18-12-2012

Gist”: Polyurethane/polyurea elastomer based on a softblock mixture comprising dihydroxyalkyl terminated polydimethylsiloxane and a hydroxy terminated perfluoroether (or other low Tg softblock like OH terminated polybutadiene, polyphosphazenes etc) together with a rigid diamine chain extender (DETDA type) and a diisocyanate (HMDI in the examples). The softblocks have a molecular weight of 5000 or more and a functionality of 2.

Why it is interesting:  The materials are claimed to have a Tg between -60 and -110°C with still very high elongation and tensile strength values at -100°C. The molecules are linear but will probably not melt because of the high urea content.  They will however be soluble in the correct solvents.

Tgs

Modulus-Temperature graphs of materials according to the invention.

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