Title: LOW DENSITY FOAM, MIDSOLE, FOOTWEAR, AND METHODS FOR MAKING LOW DENSITY FOAM
Number/Link: WO2015/017088
Applicant/Assignee: Nike
Publication date: 5-02-2015
“Gist”: TPU blown with supercritical CO2 and/or N2
Why it is interesting: This case relates to foamed TPU (or EVA) with densities down to 150 kg/m³. The low density is accomplished by the combination of a conventional physical blowing agent and a supercritical fluid, specifically supercritical CO2 or N2 or a combination of these. The conventional blowing agent is incorporated into the polymer pellets before these are added to the extruder while the supercritical fluid is added to the molten polymer through a port in the extruder barrel. The material is then extruded or injection moulded. Nike have filed two more patents on this technology: WO2015/017089 and WO2015/017090.
Nike shoe with foamed thermoplastic midsole
Innovation in Polyurethanes 