Title: THERMOPLASTIC POLYURETHANE FROM LOW FREE MONOMER PREPOLYMER

 Number/Link: WO2014/186111

Applicant/Assignee: Chemtura

Publication date: 20-11-2014

“Gist”: TPUs with exceptional properties are produced from “full” prepolymers with a very low free monomeric isocyanate content.

Why it is interesting: According to this invention thermoplastic polyurethanes with improved processing characteristics and with exceptional mechanical-, fatigue- and ageing properties can be produced by reacting a ‘full’ prepolymer having a low ( less than 0.5% ) free monomeric isocyanate content with a low molecular weight chain extender. PPDI and MDI prepolymers with low free monomeric isocyanate can be prepared e.g. by distillation of the prepolymer in the presence of a inert solvent with a boiling point slightly lower than the monomeric diisocyanate present (see e.g. US2009/0076239). Products like this are commerically available. The reason for the exceptional properties is undoubtedly the result of a very regular microphase structure of these TPUs.

para-phenylenediisocyanate (PPDI)