Efficiency and the environment at JEC

At the JEC composites fair in March, many of the exhibitors focused on the rising importance of carbon and natural fibres in applications that are both efficient and environmentally friendly. European Plastics News attended the fair to take a look at the applications on show

In March, more than 1,100 brand names showed their wares at the JEC 2011 composites fair in Paris, which this year had a strong focus on efficiency and the environment. Visitors were confronted by these themes right from the get-go, approaching the exhibition hall past a 40m-long, materials-efficient, carbon fibre composite pipe.

This entrance exhibit was produced by CGB Carbon Grossbauteile of Wallerstein, Germany, using T-Igel machinery from Austria based Teufelberger.

CGB managing director Bernd Schottdorf told European Plastics News that the manufacturing process for the pipes is highly efficient, as are CGB's MakroComb honeycomb-backed parts, all "with low scrap". Schottdorf added: "About 90% of the RTM (resin transfer moulding) and SMC processes here at the JEC fair are just playing around with prototypes compared with our technology."

CGB manufactures carbon pipes up to a diameter of 1,000mm and a length of 42.5m for less than €30 per kilogram, he said.

Teufelberger said the cost of incorporating metal connections into CFRP parts with its T-Igel machinery is 60% lower than processes that use staked adhesive joints because the T-Igel method has four, not five, steps, which reduces manufacturing time by 40%.

CFRP technology was also shown at JEC by Paderborn University on the Kunststoff.NRW stand. Prof Thomas Tröster, head of the LiA chair of lightweight automotive construction, showed European Plastics News CFRP/steel technology, which reinforces metal structures and enhances crash performance in automotive applications.

Tröster said partial CFRP reinforcement is most efficient when applied by pressing a CFRP pre-preg with a heated stamping tool into the already formed metal structure, while it is held in a heated mould half. After around two minutes, the semi-cured CFRP polymer bonds the fabric to the metal. Full polymer cure is reached in a second stage, for example by stoving electro-deposition paints to the metal structure.

Paderborn University also displayed examples of CFRP/steel sandwich structures with CFRP placed between the inner and outer steel layers. CFRP's high strength means manufacturers can lower weight as they would have to increase the thickness of steel four or five times to achieve the same strength, says Tröster.

A similar CFRP/steel sandwich construction is used to make a car B-pillar, as outlined in a JEC carbon fibre market forum paper by Dr Uwe Kobs, business analysis and strategic planning director at SGL Carbon.

The B-pillar concept came about thanks to the Benteler-SGL joint venture between Benteler Automotive and Fischer Composite Technology. The JV is aiming to realise a cycle time of 96 seconds, enabling production of 150,000 parts per year, and has already built a test stand with various loads for sill and roof frames.

Similarly, the ZLP centre for lightweight production technology at the DLR German aerospace centre showed an NFS/NVS New Vehicle System part. DLR engineer Arne Stahl described the part as an omega-shaped steel stiffener enveloped by CFRP inner and outer shells to form a closed-ring passenger car mid-frame.

On the NRW stand, the IKV plastics processing institute showed technologies which are designed to improve composites production efficiency, such as flow impregnation, PUR spray impregnation, RTM pre-pregging and gap impregnation.

In another CFRP/metal hybrid, epoxide resin supplier Huntsman and the UK's Bristol University showed a CFRP rim which is applied to a cast magnesium-aluminium alloy wheel hub. This CFRP/metal hybrid wheel won the JEC 2011 sports and leisure category innovation award for NRG Wheels, based in the UK. The rim is fixed to the metal hub with coated titanium fasteners and bonded bushings.

The developers claim the wheel is 40% lighter than conventional wheels, so that a Porsche fitted with the wheels consumes 10% less fuel. The higher impact strength exceeds the necessary limit for conventional cars but the wheels can be used for higher value and performance vehicles, they add.

On the Huntsman stand, the NRG wheels were shown as part of the U-Box electric concept van.

Designed by the D3 consultancy, the van uses basalt and flax fibre composites and new epoxide resins, for fast cycle resin transfer moulding. In polyurethane, the new Vitrox series is also designed for fast cycle RTM of large volume automotive and transport parts.

Flexible organic light emitting diode (OLED) lighting is also integrated within the U-Box composite bodywork.

Huntsman also supplied the Araldite epoxide resin used to make composite structures for a boat which will take part in the 2011 Mini Transat 6.50 transatlantic solo sailing race and which was on display in the JEC product showcase area.

Half of the composites used to make the boat consist of flax versions, made with flax from Belgian producer Lineo. Lineo coated the flax fibres to prevent humidity absorption to increase interfacial bond strength. The manufacturers claim the boat is the first racing vessel to have flax reinforced composites in its construction.

In a JEC bio-based materials forum presentation about the boat, Huntsman Advanced Materials' marketing manager Laurent Pourcheron said: "The coefficient of thermal expansion and elongation at break for flax are close to values for carbon fibre, while flax based composites usually have higher stiffness than glass composites."

Due to high flax fibre composite stiffness, there is potential for weight reduction over glass fibre composites, he added. Flax fibre accounts for 75-80% of the hull and deck reinforcement.

Induction heating technology company RocTool demonstrated how it uses linen fibre fabric to produce iPhone and iPad covers made of fibre-reinforced polyamide 12.

The company uses its 3iTech system to reach a PA12 melt temperature of 200°C in less than a minute before rapidly cooling the material. The covers are then trimmed, varnished and buffed.

RocTool says the technology is the only one of its kind "capable of moulding linen fibre quickly without burning or ruining its mechanical properties".

The company simultaneously launched its new FiberShell trademark to market the EcoFiber covers, alongside Performance Collection carbon fibre versions. The FiberShell cases are sold on the FiberShell website for €45 and €75, depending on size.

RocTool CEO Alexandre Guichard added: "We are thinking of developing the material for use in car interiors, car seat shells, luggage, furniture and electronics industry accessories."