Nike shoe with foamed thermoplastic midsole
February 9, 2015 12:44
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
Posted by Gerhard Bleys
Categories: Elastomers, Thermoplastics
Tags: blowing agent, comfort, elastomers, EVA, footwear, nano, TPE, TPU
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[…] Why it is interesting: The invention relates to injection moulded “flexible foams”, especially useful for footwear applications. Thermoplastic polyurethanes with a Mw of 120,000 to 500,000 and a dispersity index of 1.85 to 2.51 are foamed using a gaseous blowing agent (CO2 or C1 to C6 hydrocarbons etc. ) together with a cellopener (silicone or EO/PO surfactant), such that at least 50% of cells are open. In the examples the blowing agent is added in supercritical state to the melt before injection moulding. The type of gas used, nor the densities of the foams are mentioned. Foaming TPU with gas in supercitical has also been file by Nike as discussed before in this blog. […]
By TPU Foams | Innovation in Polyurethanes on June 23, 2017 at 15:13