Good Sports

A new generation of sports gear protects players from knocks and blows with an impact-absorbing elastomeric material. Stuart Nathan reports.

When Jerzy Dudek, Poland’s goalkeeper, runs out on to the pitch for next year’s World Cup campaign, his gloves will have a distinctive orange strip running across the knuckles.

But this isn’t just another styling point for the image-driven sportswear industry. Known as d3o, the orange material has properties that could change the way protective materials are constructed.

Based on a complex elastomeric compound discovered and developed at the University of Hertfordshire, d3o is a shear-thickening material. It is soft and flexible when moved slowly, but when it is moved fast — for example, when compressed by an impact — its molecules lock together. The material stiffens, absorbing the impact.

d3o Labs has incorporated it into a soft foam matrix, and Richard Palmer, d3o Labs’ chief executive, has devised a striking party piece to demonstrate its properties: donning a long-sleeved T-shirt with d3o panels sewn into the sleeves, he slams his elbow into the tabletop as hard as he can. Cups rattle, liquids slosh and winces are guaranteed.

The material has vast potential in the protective clothing market, said Palmer. ‘We don’t like to call it armour, because that implies rigidity. This is a soft, flexible material, like padding, until you hit it. It provides the same level of protection performance as a rigid, sacrificial form, like a bicycle helmet, but it also provides comfort. It’s the first material that combines freedom of movement with impact protection, and it represents a step change in the design philosophy behind these products.’

As a new company trying to launch a new material into an established industry, d3o is discovering the value of product design. ‘Strictly speaking, we shouldn’t be designing shoes or clothing, but we’re finding there’s a distinct advantage in making an example product,’ Palmer explained.

‘But we definitely couldn’t survive as a company without product design embedded in our business.’

The problem, according to Palmer, is that the firms d3o Labs deals with — generally in the sportswear industry — tend to think in terms of materials they know are available, and whose properties they understand. The properties of d3o are so different from those of polyurethane foam, for example, that they are unlikely even to consider it.

‘We originally thought that companies would just look at the data sheet and realise the opportunities,’ Palmer said. ‘But that seems not to happen.’

Although Palmer estimates that around 90 per cent of d3o Labs’  business comes from companies approaching them, his staff still have to demonstrate the properties of the material.

‘And to do that, we have to validate the properties through design.’

To handle this, d3o Labs employs a full-time product designer, John Sudul, whose task is both to design the components d3o Labs supplies to its clients, and to prove how they will benefit the finished products.

‘For example, when I’m designing elbow protectors for motorcycling, I have to work on the best patterns for the foam, so that it flows into the mould easily and provides the properties we need, and I also have to work on the best shape for the piece to wrap around the elbow.’

To do this, Sudul has to consider questions of shape and manufacturability, and to understand the flow properties of uncured d3o as it enters a mould.

‘I combine the processing properties and the performance of the material,’ he said.

The shape of the patterning of the piece — for example, studded for footwear, cut into triangles and hexagons for elbow panels — depends on the properties needed and where it is to be worn on the body. The channels in the elbow protectors both allow the piece to flex and give airflow for comfort and temperature control.

‘Mouldability is an important issue,’ Sudul said. ‘We have to be careful that air bubbles don’t form as the liquid flows into the mould.’

There are no plans for d3o Labs to become a manufacturing operation; currently the company subcontracts its manufacturing to a specialist in the Midlands. However, the Hove offices incorporate a small pilot facility for prototyping.

Sudul designs the pieces using CAD/CAM software, then moulds are milled on a CNC machine and filled using a dispenser adapted from polyurethane processing.

‘The properties of the foam do make processing tricky,’ said Palmer, ‘because as soon as you start to move the material, it stiffens. We’ve had to make some modifications to the dispensing equipment to cope with that.’

Despite this, Sudul said he can turn a design around, from concept to finished prototype, within 24 hours. The approach is now beginning to pay off, with products incorporating d3o appearing on the shelves. American skateboarding shoe specialist Globe approached d3o for a sole that would protect the heels of skateboarders as they land from jumps and tricks.

‘We sent them some prototypes, and they “cut and shut” them into shoes and carried out some riding trials,’ Palmer said. ‘And 74 out of the 75 riders who tested them said they were the best shoes they’d ever worn.’ The fruit of this, the striking black Icon shoe, is now on sale in the US.

The advantages of d3o in this market stem directly from its properties. Traditionally, shoes incorporating shock protection have a wedge of ethyl vinyl acetate (EVA) foam in the sole. EVA’s lack of flexibility and the thickness of the wedge entail compromises in the design.

As d3o stiffens when it absorbs impact, a slice transmits half the force of impact of the same thickness of EVA, and spreads it over double the area. This means that a much thinner slice of the material can be used, resulting in a lower-profile, lighter shoe. Plus, its flexibility gives the rider more control of the skateboard, and makes the shoe more comfortable.

Footballing technology is also picking up on d3o, with Sells incorporating the material into its Contour goalkeeping gloves and Pro Pad shinpads. In the gloves it forms a punching zone: as the ball hits the glove, the d3o layer stiffens. This serves a dual purpose, as it both protects the goalkeeper’s knuckles and provides a solid platform for him to launch the ball away.

‘Most gloves offer very little protection across the knuckles,’ said Sudul. ‘Goalkeeping gloves use a soft, high-frictional foam in the palm which is good for helping to catch the ball, but it can’t absorb the shock of a punch.

‘Sells was looking for a solution that provided shock absorption, but didn’t compromise the flexibility of the glove.’ The project involved close collaboration between d3o Labs and Sells. In this case, Sudul concentrated on designing the geometry of the insert. The design process took around six weeks from initial concept to factory production.

‘The biggest challenge was keeping the weight down and the shock absorption up, as well as maintaining breathability. That was a tooling issue more than anything else, because the holes in the material are made by small pegs in the tool which need to seal on a clamp.’

The prototype section was then tested for impact absorption, tensile strength, elongation, tear strength and breathability. And the final design, like all d3o projects, incorporated the clear window so the orange foam is visible.

‘The colour’s our trademark,’ said Sudul. ‘In this market visibility is everything.’