Having watched their wives fret over finding the perfect “out for the day” footwear, the men decided — and why not? — to pursue shoe design. More innovative, technological entrepreneurs than fashion designers, they spent four years trying to create a shoe that would be comfortable and stylish, but also environmentally friendly.
“No one takes four years to develop a shoe,” Mr. Martin said, laughing. “We didn’t know what we were doing, but it was also completely unchartered territory.”
It was four years of trial and error in design and manufacturing — they tried, but failed, to find a way to manufacture the shoes in the United States — but by last summer, the start-up was in business, with the shoes being made in China.
Rothy’s process is novel. Plastic water bottles are sourced from recycling centers, hot-washed and sterilized, then chipped into flakes and extruded into little pellets. The pellets are heated, then drawn into soft filaments of plastic. The shoes are then knitted by a computer program that has different settings for pattern, color, design and size.
Nike uses a somewhat similar method to make its Flyknit line, which was introduced in 2012. But unlike Flyknit, and other recycled-material athletic shoes, which are made in two dimensions, Rothy’s are knit in three dimensions and come out of the 3-D knitting machine seamless — the whole process takes six minutes — using almost the precise amount of material required. There is no cutting, which is the most wasteful part of normal footwear manufacture.
“We have virtually no waste,” Mr. Martin said. “And as adhesives get greener or as waterless dyeing comes to fruition and is commercially viable, we can add it to our program.”
For now the shoes, which feel like fabric, not plastic, come in just two designs: pointy-toe, called the Point ($145), and round-toe, called the Flat ($125). Because they’re knitted, they breathe like mesh. They are also machine washable and take about 40 minutes to air dry.
The shoes have amassed a loyal global clientele, many of whom can’t stop talking about them online and off.
Alexandra Legrain, who lives in Barcelona, Spain, heard about Rothy’s from her sister in California. Eager to support brands that are environmentally responsible, she bought two pairs of Rothy’s in the past three months.
“They are just so comfortable,” she said. “They are the shoes you could wear at home, but you can wear them out to dinner and they complement an outfit.”
It was through word of mouth that Jeremy Liew, a partner at Lightspeed Venture Partners, a venture capital firm in Silicon Valley, heard about Rothy’s.
“Women are the arbiters of popular culture, so we pay a lot of attention to the kind of the opportunities we see in which women are talking about how great a product is,” Mr. Liew said. In May, Rothy’s secured a $7 million Series A round of financing from Lightspeed. Other investors including Finn Capital Partners, M13 and Grace Beauty Capital invested about $2 million combined through a convertible note before the Series A funding.
Mr. Liew, who is best known as Snapchat’s first investor, thinks Rothy’s has the potential to be as successful as iconic labels like Vans, Toms and Uggs.
“They really go beyond being a shoe,” he said. “They get into the mainstream of recognition rather than just being something people know about as a shoe.”
Mr. Liew’s biggest concern is that with a wait list for styles like the black pointed-toe flat as high as 20,000, keeping up with demand may be difficult.
“It’s a high-quality problem to have, but it’s still a problem,” he said, adding that he is confident Rothy’s will find a solution. “They spent years creating these shoes and have already demonstrated that they’ll work through any problems.”
Rothy’s too are recyclable. The “fabric” portions are turned into carpet tiles, the rubber soles into yoga and gym mats.