When it comes to safety footwear, comfort is as critical as protection. Workers on their feet all day will tell you that a good safety boot, shoe or trainer needs more than just toecaps and midsoles; they also need to provide long-lasting support and fatigue-reducing properties. A relatively new material, ETPU is transforming comfort in safety footwear. Originally developed for athletic shoes, ETPU is now playing a prominent role in providing shock-absorbing comfort for wearers in safety-critical industries thanks to its unique cushioning and energy return capabilities.

In this blog, we’ll explore why ETPU is becoming the go-to material for modern footwear.

FIRST THINGS FIRST – WHAT IS TPU? 

TPU stands for Thermoplastic Polyurethane, which means it’s a plastic material that can be shaped when heated. Known for its elasticity and durability, TPU is used in many different products, including footwear, vehicle interiors and car tyres, due to its strength, flexibility and shock-absorbance, making it a high-performer in terms of comfort and durability. 

WHAT IS ETPU - AND HOW IS IT DIFFERENT? 

ETPU stands for ‘Expanded Thermoplastic Polyurethane,’ and is generally considered to be an advancement over traditional TPU.

ETPU basically takes the qualities of TPU a step further by taking the closed-cell TPU beads (pictured) and fusing them together with heat to make an ETPU particle foam.

Unlike traditional TPU, the resultant expanded thermoplastic polyurethane has much more responsive and dynamic properties. So why is this good news for feet?

HOW DOES ETPU MAKE FOOTWEAR MORE COMFORTABLE? 

ENERGY RETURN 

Footwear featuring ETPU gets its trademark ‘bounce’ or ‘spring’ because when compressed (when the foot takes a step) the air-filled cells in the expanded beads absorb this energy in a highly effectively way. 

When the pressure is released (when the foot lifts off the ground) they quickly expand back, releasing the stored energy. This ability to store and release energy is crucial for high energy return, which helps the wearer have ‘bounce’ and to propel them forward. 

This energy return is very important for safety boot wearers, because they take on average 12-15,000 steps per day. 

In the manufacturing process, because the ETPU beads are steam-heated, they expand and then fuse together. This very specific bead structure ensures a tightly bonded network is created - but due to the individual beads, the material still has excellent movement and flexibility.

This balance of both the cohesiveness and independent movement of the beads adds to the overall springiness and suppleness of the material.

ETPU in action. Pictured: V12 Footwear's forthcoming safety trainer Comet offers top-level energy return and cushioning with an ETPU midlayer.

SHOCK ABSORPTION 

Shock absorption in footwear is important because it helps prevent injuries and reduces stress on joints and muscles. When the foot strikes the ground, a shockwave travels up the leg - but a material such as ETPU absorbs a significant amount of that impact, which helps reduce the stress and force on joints and muscles as the wearer racks up their several thousand daily steps.

COMPRESSED REPLY 

The compressed reply or 'rebound value' of ETPU is more effective than TPU. Material with high compressed reply means it can return quickly to its original shape after being compressed, offering more reliable long-term comfort. 

CUSHIONING 

For outstanding comfort, ETPU is a perfect material, because the air-filled beads act as a network of tiny pillows, each working independently as well as collectively to support and cushion the foot. 

LONG-LASTING COMFORT 

When the TPU beads are heated, they expand, so the resulting ETPU material becomes both flexible and resilient, as it's able to deform under load, but can quickly spring back to its original shape. This elasticity allows it to provide consistent energy return over repeated compressions. 

ETPU maintains its energy return properties over time due to its high durability and strong resistance to deformation, and its microcellular structure means it retains its spring-like qualities, so the wearer can enjoy long-term energy return. 

In addition, it possesses excellent abrasion resistance that enables footwear to last longer under harsh environments and rigorous application.

Lightweight

Finally, ETPU is a low density material, and this couped with the expanded nature of ETPU makes it lighter than solid TPU, reducing the energy needed to compress it, and making the footwear lighter in general: and this goes a long way to enhance wearer comfort. 

WHERE CAN ETPU BE USED ON A PIECE OF FOOTWEAR? 

ETPU’s high level cushioning and energy return can be incorporated into several parts of a piece of footwear, including the outsole, insole and midlayer.

So, with high energy return which reduces fatigue, plus maximised comfort from reduced effort when walking, each step feels lighter and less strenuous, so it’s no wonder that more manufacturers are incorporating ETPU into more of their safety footwear.

So now you know a little more about safety boot materials, is it time for you to get the right pair for the job?

Why not use the V12 Footwear Boot Finder? Simply type in your safety footwear requirements including your comfort needs and work environment, and we’ll give you our expert recommendations from our range to meet the hazards of your role - and take  comfort to the maximum on every step.