It was a simple but radical idea. A single, thin layer of cloth to provide warmth, a single layer to resist the cold—a garment that could reduce bulk yet warm the body. The very idea sounds preposterous and defies the common sense of layering up for the cold that we all know so well. But 13 years ago, Uniqlo, in their ever-vigilant mission to create clothing that betters our lives, made the bold decision to challenge that common sense. To accomplish the impossible Uniqlo partnered with Toray, the leading Japanese chemical engineering firm whose products range from Ultrasuede to the carbon fiber composites used in the Boeing 787. Toray put their textile engineers to task developing fibers that could answer Uniqlo’s demands. The first viable solution was the combination of moisture-wicking polyester and hollow cotton fiber thread. And so Heattech was born.
I had the amazing opportunity last October to visit the Uniqlo headquarters in Tokyo wherein I learned about the global brand, how it started, the factors behind its success, their recycling initiatives, Uniqlo LifeWear, their overseas expansion and so much more. From the opening of their little store in Hiroshima in 1984 and look where Uniqlo is today! I also stopped by Toray’s factory in Kyoto for a crash course on how Heattech is made and tested. I got to witness the whole spinning process (where yarn becomes fabric), how they combine the four types of fibers that makes up Heattech. Just take a look at the photos below and see how technical everything looks! They even have special rooms wherein they test the Heattech with different detergents, stretch out the fabric to test how stretchable it is, etc! My favorite part of the factory was the environment control room (also known as Technorama) wherein they can recreate various environments. We watched this guy walk on a treadmill inside the freezing room, and with the help of infrared cameras that can detect body temperatures (see photo below), we saw that he was able to stay warm and dry just by wearing Heattech and a jacket. I felt like I was a kid on a fieldtrip. But this was serious business. The Japanese really takes their craft seriously.
Today’s Heattech is made up of four distinct fibers that are specifically engineered to work in tandem to provide the body with warmth and comfort.The first fabric in the warming process is rayon. It basically absorbs moisture from the body and through a process called heat retention; it retains the heat from the kinetic energy created by the movement of the H20 molecules (reading this hurts my brain). The second fiber is a micro-acrylic specifically developed by Toray for Heattech. These ultra-fine fibers, smooth and silk-like, are one-tenth the thickness of the human hair. Bundled together, they create air pockets that maintain the heat that’s been remitted from the rayon. The other two fibers that are part of Heattech help the fabric wear and feel better. Polyurethane is a stretchable and elastic fiber that allows Heattech to move with the body, to keep every inch of skin warm and to offer ease and comfort. The last component, polyester, allows the fabric to retain its shape and structure after multiple washings and wear.
Each year Uniqlo pushes Heattech forward, taking into account Toray’s engineering breakthroughs as well as demands from its legion of loyal customers. A team of over 30 people at Toray is constantly working to develop and redevelop Heattech’s technology to adapt to our changing lives. For Uniqlo and Toray, Heattech is always and only a beginning.