E-shots Web-exclusive: Patent check: What’s in a Croc?

Plastics are all around us, and sometimes on our feet. Ever wonder what goes into the making of the popular waterproof Croc, a rubbery molded clog with breathing holes that has swept the country by storm? So did we. Here’s what we discovered:

• The footwear is manufactured by Crocs Inc. of Niwot, CO.
• A patent on the shoe was filed on March 9, 2006.
• The material used to mold Crocs is a foamable ethylene vinyl acetate (EVA) along with polyolefin elastomer (Engage from Dow) and pigment.
• Shoes are molded, then expand up to 2.5 times upon demolding before contracting by a factor of .6.
• Mold sizes are adjusted for color because various pigments affect the expansion process differently. Without adjustment, a green shoe would be noticeably smaller than a khaki one of the same shoe size.
• The EVA material is tradenamed Levirex and is marketed by an Italian company called Finproject.
• While the shoes have been embraced by children, gardeners, and active families, the original intent of the design was to provide comfortable working shoes for people who are on their feet all day, such as doctors and nurses, while also protecting their feet from liquids and other spills.
• While the inevitable knockoffs are starting to show up, the original company (Crocs Inc.) is now branching out into new shoe designs, such as the sporty flip-flop.