This might seem like a silly question, there are shoes made by nike that have soles made of old rubber tires. Can that rubber be broken down again and recycled?
Does anyone know how Nike is doing it? Since rubber is a thermoset you can’t melt it and mold it again.
The only thing I can think of is that Nike shreds tires, grinds the shreds into granules and uses that in some virgin rubber. Almost like glass-bead filled plastic in injection molding.
If that’s the case, I would imagine that laterally recycling would have some serious limitations. I suppose you could shred up the virgin sole of the shoe. That, along with the granules that are already shredded, could then be used in another shoe. But by definition you would a shoes worth of granules, which would be enough granules for several new shoes (because they need virgin rubber as well). It sounds like it gets real exponential real fast… certainly better than using all virgin rubber, but maybe not as sustainable as “we make shoes from tires!” sounds.
Again, that’s all speculation. Anyone know any better?
I visited a rubber flooring factory last week that was using recycled rubber to compress into flooring of many varieties.
Shredded rubber, adhesive, heat pressure into huge cylinders that are skived into sheets. Not sure how the shoe soles are made, but the percentage of recycled rubber that makes up the final product in black flooring seemed like 95+ percent.
Mixed color versions were using more EPDM and less recycled materials.