How scientific research adds comfort to innovative safety footwear

Sally Ryder Taylorin Technical

Leading membrane and functional fabric manufacturer W.L. Gore and Associates has been supporting the safety footwear market since the 1990s, and the science behind the development and manufacture of Gore's laminates and technologies is a fascinating story. Here, Pitchcare looks at the history of the GORE-TEX® footwear brand and the development of the GORE-TEX® Extended Comfort Footwear range.

There is no doubt that the name GORE-TEX® branded products summons up the term 'protective outdoor clothing' for many people. The brand has become a by-word for top-quality protective clothing and footwear in the UK and abroad. The GORE-TEX® brand is well known for its durably waterproof, breathable and comfort characteristics, but how did the company develop the functional materials that ensure these qualities? And how do Gore maintain quality and stay ahead of technical and scientific innovations?

The History of Gore

The story begins in 1958 with the usage by founder Bill Gore of a polymer called polytetrafluoroethylene (PTFE) for new market opportunities, which was initially only put to use insulating cables. By 1969, his son Bob had discovered how to expand the material so that it became lighter and more porous, whilst retaining its great strength. This invention was named ePTFE (expanded polytetrafluoroethylene) and changed the future. Not only was the new material very lightweight, but it also had other very important properties. It paved the way for the waterproof, breathable GORE-TEX® Fabric.

1976 saw the first GORE-TEX® sports and leisure collection in the US and the next few years Gore products began to be used by different branches of the military and the fire service, both of which were able to utilise and appreciate the additional benefits of the anti-static and flame retardant qualities of the fabric. By the early 1980s, Great Britain and Europe were asking Gore to develop garments not only for their fire services, but also for construction workers, surgeons and a range of other work environments. At that time, safety footwear began to feature as an important component of the Gore portfolio, with requests for professional footwear designed for specific work conditions becoming ever more common.

Since then, a programme of continuous innovation and product development has resulted W.L. Gore and Associates becoming one of the leading global producers of textile laminates and a variety of other markets & industries, employing some 9000 associates with sales offices around the world.

The benefits of Gore® Functional Fabrics

Innovation and advanced technologies are built into Gore's DNA, as is the commitment to constant research & development and product testing. The company is always asking questions like 'How long can people who are exposed to harsh weather conditions in their daily work rely on their waterproof clothing?' or 'Will the boots of a soldier marching in the desert under high temperatures be able to be breathable enough and to keep feet comfortable by offering appropriate heat loss?'

Those who are active outdoors in muddy or wet or warm climate conditions all year round, are all too familiar with the challenges involved in keeping feet protected, dry and comfortable. Footwear and other PPE must reliably protect them whatever the time of year, time of day or circumstances. This is where GORE-TEX® membranes, laminates and technologies have a wide range of functionalities. They offer durable waterproofness and breathability, so the wearer stays protected in harsh conditions.

Using technology to adapt to the environment and to special work situations, Gore's functional fabrics for protective garments, shoes and gloves give wearers a second skin for doing their jobs. They durably combine protection from the outside with a healthy microclimate inside.

Manufacturing Brand Partners

Gore only works with partners around the world who have the expertise and resources to make the best possible use of its extensive portfolio of technical fabrics. In order to maintain the high Gore quality standards throughout the entire supply chain these partners are certified and licensed by Gore. The company offers them a comprehensive service which covers product testing, seam sealing equipment and full training, factory audits, as well as knowledge and support in production, design development, test equipment and marketing.

Laminates and membranes

Every GORE-TEX® end product features the GORE-TEX® membrane, which is incorporated into a specific laminate. Gore technicians are employed to thoroughly test those functional fabrics in special labs for functional performance. They must be durably waterproof, windproof, and highly breathable even when combined with other features such as flex resistance, thermal stability and resistance to certain chemicals and liquids.

Even the best functional laminate alone does not constitute a waterproof garment or footwear. For critical areas, Gore has engineered GORE-SEAM® sealing tapes and a special seam sealing process. Special solutions, like collars, waterproof pockets, front closures, bootlaces and hems with extra-wide wicking barriers, have been developed to ensure top quality end products. In this context GORE SEAM® tapes ensure that no water can enter at critical parts of the clothing or shoe.

Going the extra mile with Extended Comfort footwear

Recent technological developments in the footwear sector combined with Gore's commitment to constantly improving protection and comfort for the wearer, have led to a new class of climate comfort for professional footwear. Shoes engineered with GORE-TEX® Extended Comfort product technology have been specially designed for warm weather and combined outdoor/indoor activities.

Why this science is important to feet

The core element in this new footwear for the workplace is the GORE-TEX® Extended Comfort Laminate which is a thin 3-layer laminate that performs without insulation. The science behind extended comfort technology is important because it puts healthy feet and functionality first. Wet feet, either from external liquids or from perspiration, are susceptible to bacteria, bruising, blisters and injuries.

The laminate construction consists of a highly abrasion-resistant quick re-drying textile lining, the microporous GORE-TEX® membrane made of ePTFE and a protective knit. It's this laminate combined with a special shoe construction that gives the footwear their highly breathable and heat loss characteristics. GORE-TEX® Extended comfort footwear avoids unnecessary foam layers or other air gaps that can hinder heat conduction. Feet are protected from water and other undesirable liquids, while sweat can easily escape.

Product testing

At Gore, a shoe or boot is only cleared for mass production when its construction and performance meets the Gore's high quality and performance standards. The entire system of outer material, insulation, membrane and inner lining has to prove its excellence under the toughest conditions. The test criteria often exceeds the requirements defined in EN ISO 20345:2011 - for safety footwear or EN ISO 20347:2012 - for occupational footwear.

According to Gore's own standard GORE-TEX® Extended Comfort footwear has to withstand 300,000* flex movements (equivalent to 300 kilometres or 8 hours of walking) in ankle high water. No water entry is allowed. This is up to 60 times higher than required in EN ISO 20345/347. The boot is tested using simulated body weight and walking speeds of users with sensors in the boot reacting to the smallest amount of moisture entering the boot.

*Applies to mid/high cut shoe styles. Low cut shoe styles are tested for 100.000 flex movements.

Another test method is the Gore Centrifuge during which leakage is detected by filling the boots with water, mounting them on a centrifuge device and spun for half an hour at approximately 240 revolutions per minute. This is a patented test to identify 100% waterproof qualities much more quickly than previous methods. All Gore-certified manufacturing plants must have one of these centrifugal devices.

The GORE-TEX® Extended Comfort Laminate is also the most breathable footwear laminates in Gore's footwear laminate portfolio. Its breathability is up to six times higher than the values specified in the standard. The 3-layer GORE-TEX® Extended Comfort Laminates are "highly and extremely breathable" according to the Hohenstein comfort rating system. Its Ret values are all below 10[m2 Pa/W] acc. to ISO 11092.

In terms of durability, the GORE-TEX® Extended Comfort Laminates have to withstand 100,000 abrasion movements when dry, and 50,000 when wet, four times as many as required by the standard.

Commitment to ongoing research and quality

Gore continues its programme for continuous improvement, research and innovation, allowing it to find real solutions for real needs. The science and technology behind GORE-TEX® Extended Comfort Footwear helps explain why ground and turf workers are increasingly turning to this range of safety boots for comfort and protection.

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