Title: METHOD FOR MAKING OVER-INDEXED THERMOPLASTIC POLYURETHANE ELASTOMER PRECURSOR AND THERMOPLASTIC POLYURETHANE ELASTOMER MADE FROM THE PRECURSOR

 Patent Number & Link: WO2013/103633

Applicant/Assignee: Nike

Publication date: 11-07-2013

“Gist”: A TPU is produced at an NCO index of about 110 comprising an unsaturated chain extender .  The material can be injection moulded and subsequently cured with moisture and free radical polymerization.

Why it is interesting: A thermoplastic PU ‘precursor’ is prepared by reactive extrusion of  a polyol (e.g. a 2000MW polytetramethylene ether glycol), an unsaturated chain extender (e.g. trimethylolpropane monoallyl ether – TMPME), optional additives and MDI at an NCO index of 110 to 115 (preferred). After drying, the resulting pellets can be injection- or compression moulded and then cured by moisture and by heat or UV radiation. The resulting PU-polyurea is claimed to have improved toughness, durability and ‘scuff resistance’ compared to conventional TPUs.  The material appears to have been developed for the golf ball industry.  Nike has filed at least two related ‘golf ball patents’: WO2013/103673 and WO2013/103669.

TMPME: unsaturated chain extender used in the invention