With rock stars like BOOST and VaporMax dominating performance footwear conversations, it can be easy to overlook the nuances of a runner’s upper. But when you break it down, the technology of topside materials has come just as far as soles have – if not further – over the past 100 years or so. Form, fit, flexibility, breathability and of course aesthetic charm are all characteristics of an appropriate material. So just how did we get from cowhide to Flyknit? It’s all due to one special little fibre. Strap yourself in, it’s time to talk about nylon.
Material Matters: How Nylon Changed the (Sneaker) World
Date: January 25 2018
By: Adam Jane
For most of sneaker-centric history there have been two choices for uppers: leather or canvas. Each offers obvious advantages and disadvantages. Leather is durable and can be formed to a last, but it’s heavy and doesn’t offer much in the way of ventilation. Canvas, on the other hand, breathes but doesn’t offer the same structural advantages as leather. The footwear industry was content with these options for a long time. They weren’t out there trying to break down the door on textile technology because leather and canvas worked fine – just look at how many shoes are still made from each.
Then in 1935, a group of scientists at DuPont discovered something that would change the way the world thought about fabric. Led by a man named Wallace Carothers, the team discovered a new plastic polymer by combining hexamethylenediamine and adipic acid. They named it ‘fibre 6-6.’ Their next step was to pull fibre 6-6 into strands using a process known as cold drawing and spin the strands into thread. Luckily for us they came up with a name that rolls a little easier off the tongue than 'hexamethylenediamine mixed with adipic acid' – they named their new product nylon. The world’s first synthetic fibre, however, still had some way to go before it was ready for the footwear world.
Initially, nylon was used as an alternative for silk in women’s stockings but by 1941, DuPont’s manufacturing efforts were entirely dedicated to the military as the US jumped into the Second World War. This new focus enabled the company to develop their fibre into all manner of new applications, including ripstop fabric for parachutes – another silk alternative. After the war their attention turned back to the civilian market, which had developed a taste for all things futuristic, and by the 60s nylon was well on trend.
Towards the end of the swinging 60s, a couple of blokes named Phil Knight and Bill Bowerman were importing Tiger running shoes from Japan. Although their company Blue Ribbon Sports would eventually become Nike, the pair focused their efforts for the time being on improving the product they had. Bowerman in particular was focused on redesigning shoes themselves, and as an athletic coach he was obsessed with reducing their weight. Nylon made its athletic debut on one of the coach’s earliest designs, the TG-24, now known as the Cortez. The material in question was a kind of woven nylon marketed as ‘Swoosh Fiber’. By the time Knight and Bowerman ceased suckling on the Tiger’s teat, the material had become an integral element in Nike’s formula. The fabric produced by weaving the synthetic yarns was strong, breathable, didn’t stretch, and above all, weighed a fraction of its predecessors.
At the same time as Nike’s woven nylon revolution, the European powers at adidas were investigating another method of turning nylon into sneakers: knitting. In a woven material, the yarns are kept straight in a tight-latticed structure, but in knitting, the yarns are formed into a series of interlocking loops. It’s this looped structure that makes the end product stretchy and able to be structured with large gaps – and that’s how we get the material that we generically refer to as mesh. One of the first sneakers to use the air-permeable textile was the adidas Americana in 1971, a cup soled sneaker available in both high- and low-cut versions. To reduce multidirectional stretch and instability, mesh generally needs to be backed by a woven material and works best with an overlying structure made from leather or suede. This meant that for the first few years, the knitted synthetic fabric was suitable mainly for use in bulkier shoes, such as basketball and tennis, and not for sleek runners.
In the decades following the spread of nylon, the world has been given a seemingly endless supply of synthetic fibres, from spandex to Kevlar, through to dyneema and more recently created formulas such as PLA. Thanks to the trail blazed by nylon we now have things like the ultra-strong Nike Flywire, which is made from a modified version of NASA’s Vectran and has a tensile strength five times higher than that of steel. Those early forays into knitted nylon mesh have slowly morphed to allow brands to produce single-piece uppers made with Flyknit, a Nike tech that now uses 100 per cent recycled polyester.
It’s easy to say that this or that moment changed the direction of things, but there are very few points along the evolution of sneakers that stirred a ripple effect quite like the debut of nylon. The lasting legacy of the world’s first synthetic fibre has been so profound that we now look at decent quality leather as a luxurious alternative – oh, how times have changed!
Material Matters is our weekly tech section where we peek behind the mesh curtain and examine the building blocks of the industry. Recently, we’ve looked at Hybrids, The Weird and Whacky Sneakers of Today and Why Shoe Sizes Don't Make Sense.