monolithic shoes


I couldn’t resist these Puma Injex shoes injection molded in one piece from non-PVC (presumably Polyurethane) foam rubber: they’re light and cushy and they appear to waste less material than typical shoes. In reality these are just attractive crocs, and they made me wonder whether they represent any benefit over traditional sneakers. They weigh about a quarter as much as a normal pair of shoes, which could save 30 grams of fuel in shipping them from China. But they certainly remain toxic to manufacture, non-renewable and non-biodegradable, which begs the question why soy-based polyurethanes haven’t yet been developed to make these innovative shoes a lot more sustainable.

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  1. Posted March 4, 2009 at 11:52 am | Permalink

    Hi Lenardo,

    This mail is regarding your posting abt PUMA Injex 100 at

    You have specified that this shoe is probably made with Polyurethane.
    I just want to confirm if this shoe is made with Polyurethane?

    I think it is made with Ethylene Vinyl Acetate / Polyolefin.
    If i am right then the production process is non-toxic and this product is 100 % recyclable.
    Puma can recycle these shoes just the way Crocs does.

    Anyways, can you confirm if this shoe is made with Polyurethane?


  2. Posted March 4, 2009 at 12:22 pm | Permalink

    Hi Nitin,
    You raise a very interesting question – how can I determine the exact material? If you have any ideas please let me know. In the meantime I will add your opinion to the post.
    Thank you

  3. Posted March 4, 2009 at 12:22 pm | Permalink

    Hi Leonardo,

    My idea is that it is made with Ethylene vinyl acetate.
    I might be wrong because ethylene vinyl acetate(EVA) is not so much elastomeric but if we add some other elastomer in EVA , we can get similar results.

    Also, looking at after wearing conditions, the wrinkles at the sole part suggest that this material is EVA and not PU.

    I wish i could find out a way to reach Puma and find out what exactly are they using. But here in India, PUMA people doesnt know anything about technical aspects.

    FYI, the production process of EVA or SEBS foam is totally non-toxic and these shoes /materials are 100 % recyclable. Although it is not biodegradable.

    Have you seen Yoga Mats at NIKE? They call it TPE yoga mat. I guess this TPE might be used to make this shoe.

    Why dont you find out a chemical technologist at MIT and ask him to analyse this shoe in the lab. :D

    And if you get this thing done, please do share the results with me. :-)


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  • By Machine Shoe :: hyperexperience on March 19, 2009 at 11:06 am

    […] hardens into a shell akin to the way rubber duckies are made. While seemingly no different from the Puma Injex, these shoes are formally unique and unrelated to traditional paradigms. Perhaps a more worthwhile […]