Patent Title: THERMALLY REVERSIBLE CROSSLINKED POLYURETHANE

 Number/Link: WO2016/018956

Applicant/Assignee: Lubrizol

Publication date: 4-02-2016

“Gist”: Diels-Alder adducts of furan and maleimide are used as reversible crosslinks

Why it is interesting: Polyurethanes with thermally reversible crosslinks can be useful: these materials can be processed and recycled as thermoplastics while showing increased mechanical properties and the reduced compression set of thermosets. They can also show self-healing properties in certain circumstances.
According to this invention PU with thermally reversible crosslinks can be prepared by reacting a diisocyanate with a diol containing a furan functional group and then incorporating a polymaleimide. For example: the diol can be prepared by reacting furfurylmethacrylate with thioglycerol and the polymaleimide can be 1,1′-(methylenedi-4,1-phenylene)bismaleimide.
Interesting idea but very similar to WO2015119688 discussed before.

1,1′-(methylenedi-4,1-phenylene)bismaleimide