You may not have heard of Covered elastomeric yarn. But you’ve seen it. And you’ve most probably worn it, quite a few times. At Stretchline, we produce over 350,000kg of covered yarns each and every month (to put that into context, it’s the same weight as roughly eight and a half aeroplanes!). And there’s good reason as to why. The secret ingredient has been a driving force behind some of the biggest apparel trends over the last few years, and an important part of our sustainability efforts.

But what actually is it? And what is it used for? We break down the facts behind elastomeric yarns – one of the best kept secrets behind some of the world’s biggest trends.

What is Covered Elastomeric Yarn?

Covered Elastomeric yarns have controlled stretchability. Polyester or nylon coverings are most commonly applied to elastane yarns, giving them the ability to stretch to up to 400% of their initial length, while rapidly recovering back to their initial state afterwards.

We produce four main types of covered yarns: double covered yarn, single covered yarn, air covered yarn and air intermingled yarns. Each has its own unique purpose and properties and is found in different types of fabric products. From the single covered yarn used for waistbands in ladies’ hosiery, to double covered yarn’s ability to bring complex smocking effects to life on fashion items.

How are Covered Elastomeric Yarns made?

At the heart of Covered Elastomeric yarns are elastomer polymers. A complicated-sounding term, but the critical element that gives elastomeric yarn its stretch and recover properties.

We use a selection of different technologies – from Air Covering, a process which uses a jet of cold air to create intermittent tacks with controlled feeding of elastomer, where fibres are mingled to produce a stretchable yarn.

The technologies can vary massively, but the end result always has one goal – a superior product that turns a piece of fabric into a dynamic and comfortable garment.

What are covered Yarns used for?

The question should probably be what elastomeric yarns aren’t used for. From jackets and hoodies, to socks and hosiery. Covered yarn is quite literally the foundation of hundreds of everyday items and a common feature of almost everything that has strong stretch and recover properties.

It can be found in medical bandages and stockings, as well as gloves and a huge range of sportswear. Covered yarn’s ability to stretch without impacting the product’s initial shape has helped escalate spandex into thousands of homes since the 80s.

A secret trend-starter in more ways than one

The huge explosion of spandex and the Lycra brand isn’t the only way this intelligent fibre has made its mark, however. Covered yarns are the building block behind hundreds of the biggest trends of today. Debuted at the 2012 Olympics, FlyKnit trainers were originally developed to give superior performance on the running track – offering a lighter, more breathable second skin to those competing.

The style has since become one of the most popular and – arguably most photographed – fashions of the last few years. Pretty big fame for a very secret ingredient.

Decreasing our footprint

But sneaker/trainer footprints are arguably less important than our own (carbon) footprint. And the clever technology has helped us make a big impact there too.

Our investment in the division has allowed us to create a huge suite of sustainable solutions including 100% bio-degradable yarns for disposable items– which decompose in less than three years; reduced water use in dope-dyed and space-dyed yarns; and 100% dry operations – which mean we discharge absolutely no nasty chemicals into the environment.

Some of our most exciting innovations take place in our covered yarns processes – helping us improve the planet, as well as the end result.

Big plans for the future

It’s unlikely Covered Elastomeric yarns will ever become well-known to end consumers. But they’ll continue to be the secret foundation of hundreds of items they buy and wear – and we’ll continue to innovate with our partners to find better ways of utilising the technology in new products and new offerings.

It may be a secret ingredient, but it’s an absolutely critical one. For us, for our customers, and for the planet.