A global leader in carbon fibre and composites innovation, Hexcel will be promoting its latest products and technologies at Composites Europe 2013.
The focus of the promotions will be “making things better” – and Hexcel will show how innovations in resin matrix development and weaving technologies are transforming composite structures in automotive, wind energy, marine, sports equipment and other industrial markets.
HexPly® M79 low temperature curing prepreg
Newly launched this year, HexPly® M79 is a low temperature curing prepreg for large structures, such as wind turbine blades and boat structures. The prepreg cures much more quickly than products currently on the market – saving energy and increasing output. A number of cure cycle options are possible, including a very low temperature cure of 8-10 hours at just 70°C or a more rapid cure cycle of 4-6 hours at 80°C. This is a significant time-saving on established industry prepregs where a typical cure cycle for an 80°C curing resin matrix is 10 hours.
There is also a 60% reduction in the risk of an exothermic reaction compared to conventional wind energy prepregs - yet the new system is based on the standard epoxy chemistry that has more than 20 years of proven performance for wind blades. Another benefit is the very long out life at room temperature of at least two months, which is unusual for such a low temperature curing product.
The low temperature cure of HexPly® M79 makes it compatible with liquid epoxy resins used for infusion processing. This means that prepreg and infusion can be combined in a single wind blade structure, optimizing the benefits of both technologies to obtain stronger laminates from cost-effective processing.
PrimeTex® Gap-Free Carbon Fibre Fabrics
PrimeTex® is Hexcel’s patented carbon fibre weaving technology in which the fibres are spread in both the warp and weft directions to produce a uniform weave and gap-free finish. The PrimeTex® spreading process increases the closure factor in the fabric by 5-8% compared to conventional weaving processes (depending on the carbon tow and FAW).
The PrimeTex® spreading process also produces thinner fabrics, resulting in greater weight savings – and the new Very Light Weight PrimeTex®, at 98g/m2, can lower the mass in a composite structure even further. Laminates made with PrimeTex® have reduced porosity, leading to better mechanical performance and when used in sandwich structures the thin PrimeTex® skins have particularly high resistance to water ingress.
On Hexcel’s stand at Composites Europe will be a ski and hockey stick both made by Fischer using PrimeTex® to benefit from the twin attributes of high performance and a highly attractive finish.
PrimeTex® is also used to great effect in the contoured roof of the new BMW M6 Gran Coupe - combining elegant design with luxurious appearance. BMW claims on their website that the contoured roof effectively lowers the weight and centre of gravity of the M6 Gran Coupe for even better driving characteristics.
HexTOOL® Machinable Composite Tooling Material
Hexcel’s HexTOOL® composite tooling material has been chosen by Lamiflex to manufacture a controlled temperature mould for the RTM processing of complex shaped frames and other structures.
HexTOOL® was selected because its machinability allowed Lamiflex to easily integrate electric resistors and sensors for heating and temperature regulation within the mould. Resin inlet and outlet areas, air extraction vents and holes for centering pins were also easily drilled or machined in the required position.
HexTOOL® moulds provide a number of benefits including improved thermal performance, the production of parts to tight tolerances, much lower weight than metal tools, and a modifiable mold surface that can be repaired or adapted to design changes.
After producing multiple parts by RTM in the mould Lamiflex remarked that HexTOOL® demonstrates very high levels of tool dimensional stability, excellent vacuum integrity and durability, while being easy to maintain.
HexPly® M81 high Tg prepreg
Another new development being promoted by Hexcel at Composites Europe is HexPly® M81 – a very tough prepreg with a high Tg [glass transition temperature – the temperature above which properties start to deteriorate]. HexPly® M81 was developed for structural parts requiring very high mechanical strength. Suitable for cure temperatures ranging from 135°C to 180°C, the resulting cured laminates provide very high mechanical properties at service temperatures above 200°C.
Available with woven or unidirectional reinforcements, the prepreg can be cured by autoclave or press processes. Typical applications for HexPly® M81 are high strength car structures and sports equipment including performance bike wheels.